NZ795793A - Vent adaptor for a respiratory therapy system - Google Patents
Vent adaptor for a respiratory therapy systemInfo
- Publication number
- NZ795793A NZ795793A NZ795793A NZ79579317A NZ795793A NZ 795793 A NZ795793 A NZ 795793A NZ 795793 A NZ795793 A NZ 795793A NZ 79579317 A NZ79579317 A NZ 79579317A NZ 795793 A NZ795793 A NZ 795793A
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- vent
- housing
- flow
- hme
- membrane
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Abstract
vent assembly for a respiratory pressure therapy (RPT) system. The vent assembly may include a vent housing having a first orifice configured to receive the flow of pressurized gas from the RPT device and the vent housing having a plurality of holes to discharge pressurized gas to atmosphere; a vent housing connector having a second orifice configured to direct the flow of pressurized gas to the patient interface; and a heat and moisture exchanger (HME) comprising an HME housing and an HME material within the HME housing, wherein the vent housing and the vent housing connector are configured to be connected to, at least in part, form a cavity, and wherein the HME is positioned in the cavity when the vent assembly is assembled. nt housing connector having a second orifice configured to direct the flow of pressurized gas to the patient interface; and a heat and moisture exchanger (HME) comprising an HME housing and an HME material within the HME housing, wherein the vent housing and the vent housing connector are configured to be connected to, at least in part, form a cavity, and wherein the HME is positioned in the cavity when the vent assembly is assembled.
Description
A vent assembly for a respiratory re therapy (RPT) system. The vent assembly may e
a vent housing having a first orifice configured to receive the flow of pressurized gas from the
RPT device and the vent housing having a plurality of holes to discharge pressurized gas to
atmosphere; a vent housing connector having a second orifice configured to direct the flow of
pressurized gas to the patient interface; and a heat and moisture ger (HME) comprising
an HME housing and an HME material within the HME housing, wherein the vent housing and
the vent housing connector are configured to be connected to, at least in part, form a cavity, and
n the HME is positioned in the cavity when the vent assembly is assembled.
NZ 795793
VENT ADAPTOR FOR A RESPIRATORY Y SYSTEM
1 CROSS-REFERENCE TO RELATED APPLICATIONS
The t ation claims the benefit of U.S. Provisional Application
No. 62/443,305, filed January 6, 2017, the entire contents of which is incorporated
herein by reference.
2 BACKGROUND OF THE TECHNOLOGY
2.1 FIELD OF THE TECHNOLOGY
The present technology relates to one or more of the detection, diagnosis,
treatment, prevention and amelioration of respiratory-related disorders. The present
technology also relates to medical devices or apparatus, and their use.
2.2 DESCRIPTION OF THE RELATED ART
2.2.1 Human Respiratory System and its Disorders
The respiratory system of the body facilitates gas exchange. The nose and
mouth form the ce to the s of a patient.
The airways include a series of branching tubes, which become narrower,
shorter and more numerous as they penetrate deeper into the lung. The prime function
of the lung is gas exchange, allowing oxygen to move from the air into the venous
blood and carbon dioxide to move out. The trachea divides into right and left main
bronchi, which further divide eventually into terminal bronchioles. The bronchi make
up the conducting airways, and do not take part in gas exchange. Further divisions of
the airways lead to the respiratory bronchioles, and eventually to the alveoli. The
ated region of the lung is where the gas ge takes place, and is referred to
as the respiratory zone. See ratory Physiology”, by John B. West, Lippincott
Williams & Wilkins, 9th edition published 2012.
A range of respiratory disorders exist. Certain disorders may be
characterised by particular events, e.g. apneas, hypopneas, and hyperpneas.
Obstructive Sleep Apnea (OSA), a form of Sleep Disordered ing
(SDB), is characterized by events ing occlusion or obstruction of the upper air
passage during sleep. It results from a combination of an abnormally small upper
airway and the normal loss of muscle tone in the region of the tongue, soft palate and
ior oropharyngeal wall during sleep. The condition causes the affected patient to
stop breathing for periods typically of 30 to 120 seconds in on, sometimes 200
to 300 times per night. It often causes excessive daytime somnolence, and it may
cause cardiovascular e and brain damage. The syndrome is a common disorder,
particularly in middle aged overweight males, although a person affected may have no
awareness of the problem. See US Patent No. 4,944,310 (Sullivan).
Cheyne-Stokes Respiration (CSR) is another form of sleep disordered
breathing. CSR is a er of a patient's respiratory controller in which there are
ic alternating periods of waxing and waning ventilation known as CSR cycles.
CSR is characterised by repetitive de-oxygenation and re-oxygenation of the arterial
blood. It is possible that CSR is harmful because of the repetitive hypoxia. In some
patients CSR is associated with tive l from sleep, which causes severe
sleep disruption, increased sympathetic ty, and increased afterload. See US
Patent No. 6,532,959 (Berthon-Jones).
Respiratory Insufficiency is an umbrella term for atory disorders in
which ts are unable to ventilate enough to balance the CO2 in their blood if their
metabolic activity rises much above rest. Respiratory insufficiency may encompass
some or all of the following disorders.
Obesity Hyperventilation Syndrome (OHS) is defined as the combination
of severe obesity and awake chronic hypercapnia, in the e of other known
causes for hypoventilation. ms include dyspnea, morning headache and
excessive daytime sleepiness.
Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a
group of lower airway diseases that have certain characteristics in common. These
include increased resistance to air movement, extended expiratory phase of
respiration, and loss of the normal elasticity of the lung. Examples of COPD are
emphysema and chronic bronchitis. COPD is caused by chronic tobacco smoking
(primary risk factor), occupational exposures, air pollution and genetic factors.
Symptoms include: dyspnea on exertion, chronic cough and sputum production.
uscular Disease (NMD) is a broad term that encompasses many
diseases and ailments that impair the functioning of the muscles either directly via
intrinsic muscle pathology, or indirectly via nerve pathology. Some NMD patients are
characterised by progressive muscular impairment leading to loss of ambulation,
being wheelchair-bound, swallowing ulties, respiratory muscle weakness and,
ally, death from respiratory failure. uscular disorders can be divided
into rapidly progressive and slowly progressive: (i) Rapidly progressive disorders:
Characterised by muscle impairment that worsens over months and results in death
within a few years (e.g. Amyotrophic lateral sclerosis (ALS) and Duchenne muscular
dystrophy (DMD) in teenagers); (ii) Variable or slowly progressive disorders:
Characterised by muscle impairment that worsens over years and only mildly s
life expectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic muscular
dystrophy). Symptoms of respiratory failure in NMD include: increasing generalised
ss, dysphagia, dyspnea on exertion and at rest, fatigue, sleepiness, morning
headache, and difficulties with concentration and mood changes.
Chest wall disorders are a group of thoracic deformities that result in
inefficient ng between the respiratory muscles and the thoracic cage. The
disorders are usually characterised by a restrictive defect and share the potential of
long term hypercapnic respiratory failure. Scoliosis and/or kyphoscoliosis may cause
severe respiratory failure. Symptoms of respiratory failure include: a on
exertion, peripheral oedema, orthopnea, repeated chest ions, morning headaches,
fatigue, poor sleep quality and loss of appetite.
A range of therapies have been used to treat or ameliorate such conditions.
Furthermore, otherwise healthy individuals may take advantage of such therapies to
prevent atory disorders from g. However, these have a number of
shortcomings.
2.2.2 Therapy
Continuous Positive Airway re (CPAP) y has been used to
treat Obstructive Sleep Apnea (OSA). The mechanism of action is that continuous
positive airway pressure acts as a pneumatic splint and may t upper airway
occlusion, such as by pushing the soft palate and tongue forward and away from the
posterior oropharyngeal wall. Treatment of OSA by CPAP therapy may be voluntary,
and hence patients may elect not to comply with therapy if they find devices used to
provide such therapy one or more of: ortable, difficult to use, expensive and
aesthetically unappealing.
vasive ventilation (NIV) provides atory support to a patient
through the upper airways to assist the patient breathing and/or maintain adequate
oxygen levels in the body by doing some or all of the work of breathing. The
ventilatory support is provided via a non-invasive patient interface. NIV has been
used to treat CSR and respiratory insufficiency, in forms such as OHS, COPD, MD
and Chest Wall disorders. In some forms, the comfort and effectiveness of these
therapies may be improved.
Invasive ventilation (IV) provides ventilatory support to patients that are
no longer able to effectively breathe lves and may be ed using a
tracheostomy tube. In some forms, the comfort and effectiveness of these therapies
may be improved.
2.2.3 Treatment Systems
These therapies may be provided by a treatment system or device. Such
systems and devices may also be used to diagnose a condition t treating it.
A treatment system may comprise a Respiratory Pressure Therapy Device
(RPT device), an air circuit, a humidifier, a patient interface, and data management.
Another form of treatment system is a ular tioning device.
2.2.3.1 Patient Interface
A t interface may be used to interface respiratory equipment to its
wearer, for example by providing a flow of air to an entrance to the airways. The flow
of air may be provided via a mask to the nose and/or mouth, a tube to the mouth or a
tracheostomy tube to the trachea of a patient. Depending upon the therapy to be
applied, the patient interface may form a seal, e.g., with a region of the patient's face,
to facilitate the delivery of gas at a pressure at sufficient variance with ambient
pressure to effect therapy, e.g., at a positive pressure of about 10 cmH2O relative to
ambient pressure. For other forms of y, such as the ry of oxygen, the
patient interface may not include a seal sufficient to facilitate delivery to the airways
of a supply of gas at a positive pressure of about 10 cmH2O.
Certain other mask systems may be functionally unsuitable for the present
field. For example, purely ornamental masks may be unable to maintain a suitable
pressure. Mask systems used underwater swimming or diving may be configured to
guard against ingress of water from an external higher pressure, but not to maintain
air internally at a higher re than ambient.
Certain masks may be clinically unfavourable for the present technology
e.g. if they block airflow via the nose and only allow it via the mouth.
Certain masks may be uncomfortable or impractical for the present
technology if they require a patient to insert a portion of a mask structure in their
mouth create and maintain a seal via their lips.
Certain masks may be impractical for use while sleeping, e.g. for sleeping
while lying on one’s side in bed with a head on a pillow.
The design of a t interface presents a number of challenges. The
face has a complex three-dimensional shape. The size and shape of noses varies
considerably between individuals. Since the head es bone, cartilage and soft
tissue, different regions of the face respond differently to mechanical forces. The jaw
or mandible may move relative to other bones of the skull. The whole head may move
during the course of a period of respiratory therapy.
As a uence of these challenges, some masks suffer from being one
or more of obtrusive, aesthetically rable, costly, poorly fitting, difficult to use,
and uncomfortable especially when worn for long periods of time or when a patient is
liar with a system. For example, masks designed solely for aviators, masks
designed as part of al protection equipment (e.g. filter masks), SCUBA masks,
or for the administration of anaesthetics may be tolerable for their original
application, but nevertheless such masks may be undesirably ortable to be
worn for ed periods of time, e.g., several hours. This discomfort may lead to a
reduction in patient compliance with therapy. This is even more so if the mask is to
be worn during sleep.
CPAP therapy is highly effective to treat certain respiratory ers,
provided patients comply with y. If a mask is uncomfortable, or difficult to use
a patient may not comply with therapy. Since it is often recommended that a patient
regularly wash their mask, if a mask is difficult to clean (e.g., difficult to assemble or
emble), patients may not clean their mask and this may impact on patient
compliance.
While a mask for other applications (e.g. aviators) may not be le for
use in treating sleep disordered breathing, a mask designed for use in treating sleep
disordered breathing may be suitable for other applications.
For these reasons, patient aces for delivery of CPAP during sleep
form a distinct field.
2.2.3.1.1 Seal-forming portion
Patient interfaces may include a seal-forming portion. Since it is in direct
contact with the patient’s face, the shape and uration of the seal-forming
portion can have a direct impact the effectiveness and comfort of the patient interface.
A patient interface may be partly characterised according to the design
intent of where the seal-forming portion is to engage with the face in use. In one form
of patient interface, a seal-forming portion may comprise two sub-portions to engage
with respective left and right nares. In one form of patient interface, a seal-forming
portion may comprise a single element that surrounds both nares in use. Such single
element may be designed to for example overlay an upper lip region and a nasal
bridge region of a face. In one form of t interface a seal-forming portion may
comprise an t that surrounds a mouth region in use, e.g. by forming a seal on a
lower lip region of a face. In one form of patient interface, a seal-forming portion may
comprise a single t that surrounds both nares and a mouth region in use. These
different types of patient interfaces may be known by a variety of names by their
manufacturer including nasal masks, ace masks, nasal pillows, nasal puffs and
oro-nasal masks.
A seal-forming portion that may be effective in one region of a patient’s
face may be inappropriate in another region, e.g. e of the different shape,
structure, variability and sensitivity regions of the patient’s face. For example, a seal
on swimming goggles that overlays a patient’s forehead may not be appropriate to use
on a patient’s nose.
Certain seal-forming portions may be ed for mass manufacture such
that one design fit and be comfortable and effective for a wide range of different face
shapes and sizes. To the extent to which there is a mismatch between the shape of the
patient’s face, and the seal-forming portion of the mass-manufactured patient
ace, one or both must adapt in order for a seal to form.
One type of seal-forming n extends around the periphery of the
patient interface, and is intended to seal against the patient's face when force is
applied to the t interface with the seal-forming portion in confronting
engagement with the patient's face. The seal-forming portion may include an air or
fluid filled cushion, or a d or formed surface of a resilient seal element made
of an elastomer such as a rubber. With this type of seal-forming portion, if the fit is
not te, there will be gaps between the orming portion and the face, and
additional force will be required to force the patient interface against the face in order
to achieve a seal.
Another type of seal-forming portion incorporates a flap seal of thin
material positioned about the periphery of the mask so as to provide a self-sealing
action against the face of the patient when positive pressure is applied within the
mask. Like the previous style of seal forming portion, if the match between the face
and the mask is not good, additional force may be required to achieve a seal, or the
mask may leak. Furthermore, if the shape of the orming portion does not match
that of the patient, it may crease or buckle in use, giving rise to leaks.
Another type of seal-forming portion may comprise a friction-fit element,
e.g. for insertion into a naris, however some patients find these uncomfortable.
r form of seal-forming portion may use adhesive to achieve a seal.
Some patients may find it inconvenient to constantly apply and remove an adhesive to
their face.
A range of patient interface seal-forming portion technologies are
disclosed in the following patent applications, assigned to ResMed Limited: WO
1998/004,310;
One form of nasal pillow is found in the Adam Circuit manufactured by
Puritan Bennett. Another nasal pillow, or nasal puff is the subject of US Patent
4,782,832 (Trimble et al.), assigned to Puritan-Bennett Corporation.
ResMed Limited has manufactured the following products that
incorporate nasal pillows: SWIFTTM nasal pillows mask, SWIFTTM II nasal pillows
mask, SWIFTTM LT nasal pillows mask, SWIFTTM FX nasal pillows mask and
MIRAGE LIBERTYTM full-face mask. The following patent applications, assigned to
ResMed d, describe examples of nasal pillows masks: International Patent
ation WO2004/073,778 (describing t other things aspects of the
ResMed Limited SWIFTTM nasal s), US Patent Application 2009/0044808
(describing amongst other things aspects of the ResMed Limited SWIFTTM LT nasal
pillows); International Patent Applications
(describing amongst other things s of the ResMed Limited MIRAGE
LIBERTYTM full-face mask); International Patent Application
ibing amongst other things aspects of the ResMed Limited SWIFTTM FX nasal
pillows).
2.2.3.1.2 oning and ising
A seal-forming portion of a patient interface used for positive air re
therapy is subject to the corresponding force of the air pressure to t a seal. Thus
a variety of techniques have been used to position the seal-forming portion, and to
maintain it in sealing relation with the appropriate portion of the face.
One technique is the use of adhesives. See for example US Patent
Application ation No. US 2010/0000534. However, the use of adhesives may
be uncomfortable for some.
Another technique is the use of one or more straps and/or stabilising
harnesses. Many such harnesses suffer from being one or more of ill-fitting, bulky,
uncomfortable and awkward to use.
2.2.3.1.3 Vent technologies
Some forms of patient ace s may include a vent to allow the
washout of exhaled carbon dioxide. The vent may allow a flow of gas from an interior
space of the patient interface, e.g., the plenum chamber, to an exterior of the patient
interface, e.g., to ambient. The vent may comprise an orifice and gas may flow
through the orifice in use of the mask. Many such vents are noisy. Others may
become blocked in use and thus provide icient washout. Some vents may be
disruptive of the sleep of a bed partner 1100 of the patient 1000, e.g. through noise or
focussed airflow.
ResMed Limited has developed a number of improved mask vent
technologies. See International Patent Application ation No.
International Patent Application Publication No.
6,581,594; US Patent Application Publication No. US 2009/0050156; US Patent
Application Publication No. 2009/0044808.
Table of noise of prior masks (ISO 17510-2:2007, 10 cmH2O pressure at
Mask name Mask type hted A-weighted Year (approx.)
sound power sound pressure
level dB(A) dB(A)
(uncertainty) (uncertainty)
Glue-on (*) nasal 50.9 42.9 1981
ResCare nasal 31.5 23.5 1993
standard (*)
ResMed nasal 29.5 21.5 1998
MirageTM (*)
ResMed nasal 36 (3) 28 (3) 2000
UltraMirageTM
ResMed nasal 32 (3) 24 (3) 2002
Mirage
ActivaTM
ResMed nasal 30 (3) 22 (3) 2008
Mirage
MicroTM
ResMed nasal 29 (3) 22 (3) 2008
MirageTM
SoftGel
ResMed nasal 26 (3) 18 (3) 2010
TM FX
ResMed nasal pillows 37 29 2004
Mirage SwiftTM
ResMed nasal pillows 28 (3) 20 (3) 2005
Mirage SwiftTM
ResMed nasal pillows 25 (3) 17 (3) 2008
Mirage SwiftTM
ResMed AirFit nasal pillows 21 (3) 13 (3) 2014
(* one specimen only, measured using test method specified in ISO 3744
in CPAP mode at 10 cmH2O)Sound pressure values of a y of objects are listed
below
Object A-weighted sound pressure dB(A) Notes
Vacuum cleaner: k 68 ISO 3744 at 1m
Walter Broadly Litter Hog: B+ distance
Grade
Conversational speech 60 1m distance
e home 50
Quiet library 40
Quiet bedroom at night 30
Background in TV studio 20
2 Respiratory Pressure Therapy (RPT) Device
Air pressure generators are known in a range of applications, e.g.
industrial-scale ventilation systems. However, air pressure generators for medical
applications have particular requirements not fulfilled by more generalised air
pressure generators, such as the reliability, size and weight requirements of medical
devices. In addition, even devices designed for medical treatment may suffer from
shortcomings, pertaining to one or more of: comfort, noise, ease of use, efficacy, size,
weight, manufacturability, cost, and reliability.
An example of the special ements of certain RPT devices is acoustic
noise.
Table of noise output levels of prior RPT devices (one specimen only,
measured using test method specified in ISO 3744 in CPAP mode at 10 cmH2O).
RPT Device name A-weighted sound power Year (approx.)
level dB(A)
C-Series TangoTM 31.9 2007
C-Series TangoTM with Humidifier 33.1 2007
S8 EscapeTM II 30.5 2005
S8 EscapeTM II with H4iTM Humidifier 31.1 2005
S9 AutoSetTM 26.5 2010
S9 tTM with H5i Humidifier 28.6 2010
One known RPT device used for treating sleep disordered breathing is the
S9 Sleep Therapy System, manufactured by ResMed Limited. r example of an
RPT device is a ventilator. Ventilators such as the ResMed Stellar™ Series of Adult
and Paediatric Ventilators may provide support for invasive and non-invasive nondependent
ventilation for a range of patients for treating a number of conditions such
as but not limited to NMD, OHS and COPD.
The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator may
provide support for invasive and non-invasive dependent ventilation suitable for adult
or paediatric patients for ng a number of conditions. These ventilators provide
volumetric and tric ventilation modes with a single or double limb t.
RPT devices typically comprise a pressure generator, such as a motor-driven blower
or a compressed gas oir, and are configured to supply a flow of air to the airway
of a patient. In some cases, the flow of air may be supplied to the airway of the patient
at positive pressure. The outlet of the RPT device is connected via an air circuit to a
patient interface such as those bed above.
The designer of a device may be ted with an te number of
choices to make. Design criteria often conflict, meaning that certain design choices
are far from routine or inevitable. Furthermore, the comfort and efficacy of certain
aspects may be highly sensitive to small, subtle changes in one or more parameters.
2.2.3.3 Humidifier
Delivery of a flow of air without humidification may cause drying of
airways. The use of a humidifier with an RPT device and the patient interface
produces humidified gas that minimizes drying of the nasal mucosa and increases
patient airway comfort. In addition in cooler climates, warm air applied generally to
the face area in and about the patient interface is more comfortable than cold air. A
range of artificial humidification devices and systems are known, however they may
not fulfil the specialised ements of a medical fier.
l humidifiers are used to increase humidity and/or temperature of
the flow of air in relation to t air when required, typically where the patient
may be asleep or resting (e.g. at a hospital). A medical humidifier for bedside
placement may be small. A medical humidifier may be configured to only humidify
and/or heat the flow of air delivered to the patient without humidifying and/or g
the patient’s surroundings. Room-based s (e.g. a sauna, an air conditioner, or
an ative cooler), for example, may also humidify air that is breathed in by the
patient, r those systems would also humidify and/or heat the entire room,
which may cause discomfort to the occupants. Furthermore medical fiers may
have more stringent safety constraints than industrial humidifiers
While a number of medical fiers are known, they can suffer from
one or more shortcomings. Some medical humidifiers may provide inadequate
humidification, some are difficult or inconvenient to use by patients.
2.2.3.4 Data Management
There may be clinical reasons to obtain data to determine whether the
t prescribed with respiratory therapy has been “compliant”, e.g. that the patient
has used their RPT device according to certain a “compliance rule”. One example of a
compliance rule for CPAP therapy is that a patient, in order to be deemed compliant,
is required to use the RPT device for at least four hours a night for at least 21 of 30
consecutive days. In order to determine a patient's compliance, a er of the RPT
device, such as a health care provider, may manually obtain data describing the
patient's therapy using the RPT device, calculate the usage over a ermined time
period, and compare with the ance rule. Once the health care provider has
determined that the patient has used their RPT device according to the compliance
rule, the health care provider may notify a third party that the patient is compliant.
There may be other s of a patient’s therapy that would benefit from
communication of therapy data to a third party or external system.
Existing processes to communicate and manage such data can be one or
more of costly, time-consuming, and error-prone.
2.2.3.5 Mandibular repositioning
A mandibular repositioning device (MRD) or mandibular advancement
device (MAD) is one of the ent options for sleep apnea and snoring. It is an
adjustable oral appliance available from a dentist or other er that holds the
lower jaw (mandible) in a forward position during sleep. The MRD is a removable
device that a patient inserts into their mouth prior to going to sleep and removes
following sleep. Thus, the MRD is not designed to be worn all of the time. The
MRD may be custom made or produced in a standard form and includes a bite
impression portion designed to allow fitting to a patient’s teeth. This mechanical
protrusion of the lower jaw expands the space behind the tongue, puts tension on the
geal walls to reduce collapse of the airway and shes palate vibration.
In certain examples a mandibular advancement device may comprise an
upper splint that is intended to engage with or fit over teeth on the upper jaw or
maxilla and a lower splint that is intended to engage with or fit over teeth on the upper
jaw or mandible. The upper and lower splints are connected together lly via a
pair of connecting rods. The pair of connecting rods are fixed symmetrically on the
upper splint and on the lower splint.
In such a design the length of the connecting rods is selected such that
when the MRD is placed in a patient’s mouth the le is held in an advanced
position. The length of the connecting rods may be adjusted to change the level of
protrusion of the mandible. A dentist may determine a level of protrusion for the
mandible that will determine the length of the connecting rods.
Some MRDs are structured to push the mandible forward relative to the
maxilla while other MADs, such as the ResMed Narval CC™ MRD are designed to
retain the mandible in a forward position. This device also reduces or minimises
dental and temporo-mandibular joint (TMJ) side s. Thus, it is configured to
minimises or prevent any movement of one or more of the teeth.
2.2.4 sis and Monitoring Systems
Clinical experts may be able to diagnose or monitor patients adequately
based on person observation. However, there are stances where a al
expert may not be available, or a clinical expert may not be affordable. In some
circumstances different clinical experts may disagree on a patient’s condition. A given
clinical expert may apply a different rd at different times. With a busy clinical
practice, a clinician may have difficulty keeping up with evolving patient
management guidelines.
Polysomnography (PSG) is a conventional system for diagnosis and
sis of cardio-pulmonary ers, and typically involves expert clinical staff
to both apply and/or interpret. PSG lly involves the placement of 15 to 20
contact sensors on a person in order to record various bodily signals such as
electroencephalography (EEG), electrocardiography (ECG), electrooculograpy
(EOG), electromyography (EMG), etc. r, while they may be suitable for their
usual application in a clinical setting, such systems are complicated and potentially
expensive, and / or may be uncomfortable or impractical for a patient at home trying
to sleep.
3 BRIEF SUMMARY OF THE TECHNOLOGY
The present technology is directed towards providing medical devices
used in the diagnosis, amelioration, treatment, or prevention of atory disorders
having one or more of improved comfort, cost, cy, ease of use and
manufacturability.
A first aspect of the present technology relates to apparatus used in the
diagnosis, amelioration, treatment or prevention of a respiratory disorder.
Another aspect of the present technology relates to methods used in the
diagnosis, amelioration, ent or prevention of a respiratory disorder.
An aspect of certain forms of the present technology is to provide methods
and/or apparatus that improve the ance of patients with respiratory therapy.
A first form of the t technology includes a connector set with a
compliant face seal between a first end and a second end of the tor set and with
a retention mechanism that couples the first end and the second end together.
A second form of the present technology comprises a fluid tor for
delivery of breathing gas to a patient from a respiratory pressure therapy device, the
fluid connector comprising a first end with a first opening for a fluid flow, a seal
n extending around a periphery of the first opening, and a latching portion, a
second end with a second opening for the fluid flow, a sealing surface extending
around a periphery of the second opening and ured to engage the seal portion to
form a face seal, and a complementary ng portion configured to engage with the
latching portion, wherein the face seal allows the breathing gas to travel between the
first opening and the second opening, and the engagement between the latching
portion and the complementary latching portion secures the first end with the second
A third form of the present logy comprises a system for providing
respiratory y to a patient, the system comprising a respiratory pressure y
device; an air circuit; a patient interface connected to the air circuit and a means for
preventing the respiratory pressure therapy device from being connected to the air
circuit with an industry standard connection.
A fourth form of the present technology comprises a method of providing
a fluid connection to deliver breathing gas to a patient from a respiratory pressure
therapy device, the method comprising engaging a latch between a first end and a
second end of the fluid connection; and engaging a face seal around a first opening in
the first end and around a second opening in the second end, n one of the first
end and the second end corresponds to the respiratory pressure therapy device.
A fifth form of the present technology comprises a first half of a fluid
connector system for delivery of breathing gas to a patient from a respiratory pressure
therapy device, the first half sing connector portion with a first opening for a
fluid flow, a seal portion extending around a periphery of the first opening, and a
latching n, n the seal portion is configured to seal against a sealing
surface extending around a periphery of a second opening to form a face seal with a
second half of the fluid connector system, and the latching portion is configured to
latch with another latching portion of the second half of the fluid connector system.
A sixth form of the present technology comprises a first half of a fluid
connector system for delivery of breathing gas to a t from a respiratory pressure
therapy , the first half comprising a tor portion with a first g for a
fluid flow, a sealing surface around a periphery of the first g, and a latching
portion, wherein the sealing surface is configured to receive a seal portion extending
around a periphery of a second opening to form a face seal with a second half of the
fluid connector system, and the ng portion is configured to latch with another
latching portion of the second half of the fluid connector system.
A seventh form of the t technology comprises a fluid connector for
delivery of breathing gas to a patient from a respiratory pressure therapy device, the
fluid connector comprising a first end with a first interior portion for a fluid flow and
a first retaining portion, and a second end with a second interior portion for the fluid
flow and a complementary ing portion configured to engage with the retaining
portion, wherein the first interior portion and the second interior portion have a first
shape perpendicular to a flow direction, the retaining portion and the complementary
retaining portion have a second shape dicular to the flow direction, and the first
shape and the second shape are different.
An eighth form of the present logy comprises a system for
providing atory therapy to a patient, the system comprising a respiratory
pressure therapy device; an air circuit; a patient interface connected to the air circuit,
the patient interface being specially adapted to operate with the atory pressure
therapy device; and a means for ensuring that the patient interface that is specially
adapted to operate with the respiratory pressure therapy device is connected to the
respiratory pressure y device.
In examples of at least one of the first through eighth forms of the present
technology, (a) the first end is connected to a respiratory pressure y device
including a blower and the second end is connected to a fluid conduit; (b) the
respiratory pressure therapy device is configured to provide treatment pressure for the
sleep related breathing disorder; (c) the sealing surface is flat; (d) the sealing surface
is ntially perpendicular to a direction of the fluid flow from the first end to the
second end; (e) the sealing surface is beveled; (d) the sealing surface extends
circumferentially around the second g; (e) the sealing surface is formed on a
flange that extends ly from a tube defining the second opening; (f) the flange
extends substantially perpendicularly from the tube; (g) the tube extends beyond the
flange in a direction towards the seal portion; (h) the tube extends at least partially
though the seal portion when the complementary latching portion is engaged with the
latching portion; (i) the seal portion is compliant in a direction of engagement
n the first end and the second end; (j) the seal portion includes a frustoconical
portion; (k) the frustoconical portion contacts the sealing surface to form the face seal;
(l) the seal portion es a partial spherical surface; (m) the partial spherical
surface contacts the sealing surface to form the face seal; (n) the seal portion includes
a bellows-shaped or partial s-shaped portion; (o) the bellows-shaped or partial
bellows-shaped portion contacts the g surface to form the face seal; (p) when the
first end and the second end are connected the seal portion is configured to engage the
sealing surface before the latching portion and the complementary latching portion
engage; (q) the seal portion is compliant in a direction radial to an axis defined by a
direction of engagement between the first end and the second end; (r) the seal portion
is configured to expand and engage the g surface due to al rization
of the first end when a gap exists between the seal portion and the sealing surface in
an unpressurized state; (s) t between the seal portion and the sealing surface
causes the seal portion to compress against the g and against an airflow
direction that is from the first opening to the second opening; (t) compression of the
seal portion does not cause significant compressive forces; (u) a force required to
compress the seal portion is less than a force required to engage the latching n
with the complementary latching portion; (v) the force required to compress the seal
portion is less than half of the force required to engage the latching portion with the
complementary ng portion; (w) the force ed to compress the seal portion is
less than one tenth of the force required to engage the latching portion with the
mentary latching portion; (x) at least one of the seal portion and the sealing
surface includes ient contact area between the seal portion and the sealing
surface to form a seal when respective centers of the seal portion and the sealing
surface are not aligned with one another; (y) the second end comprises an inner
portion and an outer portion and the inner portion is rotatably coupled to the outer
portion; (z) the inner portion ses the sealing surface; (aa) the inner portion is
rigidly connected to a fluid t; (bb) the outer portion comprises the
complementary latching portion; (cc) the complementary latching n comprises a
cantilevered portion with a protrusion that is configured to engage the latching
portion; (dd) the cantilevered portion is configured to be depressed to engage or
disengage the complementary latching portion from the latching portion and allow
engagement or disengagement between the first end and the second end; (ee) the first
end comprises a travel limit to constrain the second end from moving in a ion of
engagement between the first end and the second end; (ff) the travel limit is a flange
around the first opening and the second end comprises a stop surface configured to
contact the flange; (gg) the ng portion constrains the second end from moving in
a direction opposite to the direction of engagement, and the travel limit and latching
portion together define a movement distance of the second end when the first end and
the second end are d; (hh) the seal portion is configured to seal against the
sealing surface throughout the movement distance, the movement ce being a
ro distance; (ii) the seal portion is configured to form a seal with the sealing
surface with a worst case manufacturing tolerance and after a predetermined amount
of wear and/or creep in the fluid connector; (jj) the fluid connector is configured to
provide negligible re drop when air is flowing through the fluid connector
throughout a patient’s breathing cycle and at res between 4 cm H2O to 40 cm
H2O; (kk) the first end is a female connection and the second end is a male
connection; (ll) the female connection and the male connection have profiles that are
non-circular; (mm) the first end es a port in fluid communication with an
interior of the seal portion and separated from the first opening and the second
opening; (nn) the first opening and the second opening are interior portions of tubes;
(oo) the first end is ted to a respiratory re therapy device including a
blower and the second end is connected to an adapter for a fluid conduit connector;
(pp) the fluid connector further comprises an industry standard fluid connection,
wherein the industry standard fluid connection is in fluid communication with the first
opening and on an end opposite the seal portion; (qq) the fluid connector further
comprises an industry standard fluid connection, wherein the industry standard fluid
connection is in fluid communication with the first opening and on an end opposite
the sealing surface; (rr) the first shape is a circle and the second shape includes
properties of a circle and a square; and/or (ss) one of the first interior portion and the
second interior portion includes a first male portion and the other of the first interior
portion and the second interior portion includes a first female portion, the first male
portion and the first female portion including the first shape, and one of the retaining
portion and the complementary retaining portion includes a second male portion and
the other of the retaining n and the complementary retaining portion es a
second female portion, the second male portion and the second female n
including the second shape.
An aspect of one form of the present technology is a portable RPT device,
including a fluid connector, that may be d by a , e.g., around the home of
the person.
Another aspect of the present technology is directed to a vent assembly for
a respiratory pressure y (RPT) system. The vent assembly comprising: a vent
housing defining a central orifice for the flow of pressurized gas to pass h the
vent assembly from the delivery conduit to the patient interface, the vent housing
having an annular surface around the central orifice, and the annular surface having a
ity of holes to discharge pressurized gas to atmosphere; and a membrane
oned adjacent to the annular surface, wherein the membrane is movable such
that the membrane is urged against the annular surface of the vent housing as the
pressure of the pressurized gas within the vent ly increases.
Another aspect of the present technology is directed to an RPT system,
comprising: the vent assembly described in the preceding paragraph; an RPT device
configured to generate a flow of pressurized gas in the range of 4-20 cm H20; a
t interface configured to deliver the flow of pressurized gas to the patient’s
airways, the patient ace being non-vented; and a delivery conduit configured to
deliver the flow of rized gas from the RPT device to the patient interface.
In examples of the vent assembly and the RPT system described in the
two preceding paragraphs, (a) the plurality of holes may comprise a first group of
holes and a second group of holes, the first group of holes being proximal to the
central e ve to the second group of holes, (b) the membrane may be shaped
and dimensioned such that the membrane does not cover the first group of holes, (c)
the membrane may be structured to cover more of the second group of holes as the
pressure of the pressurized gas within the vent assembly increases, (d) the first group
of holes may be positioned upstream of the second group of holes relative to the flow
of rized gas, (e) the vent assembly may further comprise a retaining ure to
retain the membrane in a position nt to the annular surface of the vent housing,
(f) the membrane may further comprise an elastic material, (g) the ne may be
ring-shaped, (h) the membrane may not be joined to the vent housing, (i) the
membrane may be shaped and ioned such that an outer edge of the membrane
is adjacent to an inner periphery of the vent housing, and/or (j) each of the plurality of
holes may have a shape that converges from an internal surface of the vent housing to
an external surface of the vent housing.
Another aspect of the present technology is directed to a vent adaptor for a
for a respiratory pressure therapy (RPT) system. The vent adaptor comprises: a vent
assembly comprising: a vent housing defining a central orifice for the flow of
pressurized gas to pass through the vent assembly from the delivery conduit to the
patient interface, the vent housing having an annular e around the central
orifice, and the annular surface having a plurality of holes to discharge pressurized
gas to here; and a membrane positioned adjacent to the annular surface; and a
diffusing member.
Another aspect of the present technology is directed to an RPT system.
The RPT system comprising: the vent adaptor described in the preceding paragraph;
an RPT device configured to generate a flow of pressurized gas in the range of 4-20
cm H20; a patient interface configured to deliver the flow of pressurized gas to the
patient’s s, the patient interface being nted; and a ry conduit
ured to deliver the flow of pressurized gas from the RPT device to the patient
interface.
In examples of the vent adaptor and the RPT system described in the two
preceding paragraphs, (a) the membrane may be movable such that the membrane is
urged against the annular surface of the vent housing as the pressure of the
pressurized gas within the vent ly ses, (b) the plurality of holes may
comprise a first group of holes and a second group of holes, the first group of holes
being proximal to the central orifice relative to the second group of holes, (c) the
membrane may be shaped and dimensioned such that the ne does not cover
the first group of holes, (d) the membrane may be structured to cover more of the
second group of holes as the pressure of the pressurized gas within the vent assembly
ses, (e) the first group of holes may be positioned upstream of the second group
of holes relative to the flow of pressurized gas, (f) the vent adaptor may further
comprise a retaining structure to retain the membrane in a on nt to the
annular surface of the vent housing, (g) the membrane may further comprise an elastic
material, (h) the membrane may be ring-shaped, (i) the membrane may not be joined
to the vent housing, (j) the membrane may be shaped and ioned such that an
outer edge of the membrane is adjacent to an inner periphery of the vent housing, (k)
each of the plurality of holes may have a shape that converges from an internal
e of the vent housing to an external surface of the vent housing, (l) the vent
adaptor may comprise a heat and re exchanger (HME) that may be positioned
downstream of the plurality of holes relative to the flow of pressurized gas, (m) the
diffusing member may be positioned on the exterior of the vent housing to at least
partly cover the plurality of holes, (n) the vent adaptor may r comprise a
blocking member having an air-impermeable material, the blocking member
preventing gas exiting from the plurality of holes from flowing through the diffusing
member to atmosphere in a linear path, (o) the ing member and the blocking
member may be configured to direct the gas exiting from the plurality of holes
outward from the diffusing member in an orientation different than the plurality of
holes, (p) the diffusing member may provide a flow path parallel to a surface of the
ng member that is in contact with the diffusing member, (q) the diffusing
member may be a porous material, (r) the diffusing member may be an open cell
foam, and/or (s) the diffusing member may be a fibrous material.
An aspect of the t technology is directed to a vent system for use
with a patient interface during respiratory therapy of a patient with a therapy flow of
gas pressurized above ambient pressure, the vent system providing a vent flow of gas
to discharge gas d by the patient from a pressurized volume, the vent flow
being continuous during the respiratory therapy. The vent system comprises a vent
housing comprising a base having an inlet for the therapy flow of gas extending
through the base and at least one first orifice extending through the base to allow gas
to be discharged to atmosphere from the pressurized ; at least one second
orifice to allow gas to be rged to atmosphere from the pressurized volume; and
a membrane positioned adjacent to the base.
An aspect of the present technology is directed to a vent system for use
with a patient interface during respiratory therapy of a patient with a therapy flow of
gas pressurized above ambient pressure, the vent system providing a vent flow of gas
to discharge gas d by the patient from a pressurized volume, the vent flow
being continuous during the respiratory therapy. The vent system comprises a vent
housing sing a base having at least one first orifice extending through the base
to allow gas to be discharged to atmosphere from the pressurized volume; at least one
second e to allow gas to be discharged to atmosphere from the pressurized
volume; and a membrane positioned adjacent to the base, wherein the pressurized
volume is in fluid communication with atmosphere through the at least one first
orifice and the at least one second orifice throughout a eutic pressure range, and
wherein the ne is elastically able due to pressure within the rized
volume to apportion the vent flow between the at least one first orifice and the at least
one second orifice throughout the therapeutic pressure.
In examples, (a) the vent housing may comprise an outer wall and an inner
wall, the inner wall defining an inlet for the therapy flow of gas, and the base may be
positioned between the outer wall and the inner wall, (b) the base the base may
se an inner base and an outer base, (c) the outer base may be adjacent to the
outer wall, the inner base may be adjacent to the outer base, and the inner base may be
adjacent to the inner wall, (d) the at least one first orifice may comprise a plurality of
inner orifices and the at least one second orifice may comprise a plurality of outer
orifices, (e) the plurality of outer es may pass through the outer base and the
plurality of inner orifices may pass between the outer base and the inner base, (f) the
vent system may comprise a plurality of base connectors to join the inner base and the
outer base and to divide the ity of inner orifices, (g) the vent system may
comprise a plurality of membrane spacers extending from the inner base, (h) the
membrane may be supported over the plurality of inner orifices on the outer base and
the membrane spacers, (i) the vent housing may comprise a base divider between the
inner base and the outer base and the membrane may be supported over the plurality
of inner orifices on the base divider and the membrane spacers, (j) the plurality of
membrane spacers may define a ity of membrane spacer gaps between adjacent
ones of the plurality of membrane spacers, (k) the membrane may include an
atmosphere-side surface adjacent to the inner base and the outer base of the vent
housing and an inner e defining a membrane opening and an inner base
membrane passage for the washout flow may be defined between the atmosphere-side
surface of the membrane and the inner base of the vent housing, (l) an inner wall
membrane passage for the washout flow may be defined between the inner surface of
the membrane and the inner wall of the vent housing, (m) the inner base may
comprise a plurality of inner base slots between adjacent ones of the plurality of
membrane spacers, (n) the outer base may comprise a plurality of lateral membrane
ts that are configured to prevent the membrane from covering the plurality of
outer orifices, (o) the vent g may comprise a plurality of es opposite the
outer base and at least one of the plurality of outer orifices may open into a
ponding one of the plurality of recesses, (p) the inner wall may extend above
the inner base and the outer base, (q) the inner wall may extend below the inner base
and the outer base, (r) the membrane may ses an elastically able
material, (s) the elastically deformable material may comprise ne, (t) the vent
housing may be formed from a single, neous piece of a relatively rigid
material, (u) the relatively rigid material may be polycarbonate, (v) the outer wall, the
inner wall, the inner base, the outer base, and the membrane may be circular, (w) the
outer wall, the inner wall, the inner base, the outer base, and the membrane may be
concentric, and/or (x) the membrane may not be attached to the vent housing such that
the membrane is freely movable towards and away from the base.
Another aspect of the present technology is ed to a patient interface
comprising: a seal-forming structure; a plenum chamber joined to the seal-forming
structure; a positioning and stabilising structure to secure the patient interface on the
t in use; and the vent system according to any of the aspects and/or examples
disclosed in the two immediately ing paragraphs. The patient interface may
comprise a vent connector tube or a ling structure to fluidly connect the vent
system to the plenum chamber.
Another aspect of the present technology is directed to a vent system for
use with a patient interface during respiratory therapy of a patient with a y flow
of gas pressurized above ambient pressure, the vent system providing a vent flow of
gas to discharge gas exhaled by the patient from a pressurized , the vent flow
being continuous during the respiratory therapy. The vent system comprises a vent
housing a base having at least one first orifice ing h the base to allow gas
to be discharged to atmosphere from the pressurized volume; at least one second
orifice to allow gas to be discharged to atmosphere from the pressurized volume; and
a membrane oned adjacent to the base, wherein the pressurized volume is in
fluid communication with atmosphere through the at least one first orifice and the at
least one second orifice throughout a therapeutic pressure range, wherein the
membrane is configured such that an se in pressure within the pressurized
volume causes the membrane to ct a first vent flow through the at least one first
orifice throughout the therapeutic pressure range, and wherein restriction of the first
vent flow through the at least one first orifice causes an increase in a second vent flow
through the at least one second orifice such that the vent flow through the at least one
first orifice and the at least one second orifice is approximately constant throughout
the therapeutic pressure range.
In examples, (a) the vent housing may comprise an outer wall and an inner
wall, the inner wall defining an inlet for the therapy flow of gas, and the base may be
positioned between the outer wall and the inner wall, (b) the t flow may be
greater than or equal to the sum of the first vent flow and the second vent flow, (c) the
membrane may be elastically deformable toward the base in use such that the first
vent flow is restricted as the membrane is deflected towards the base, (d) the
membrane may be configured to deflect closer to the base as the therapy pressure
increases above a threshold therapy pressure value, (e) the membrane may be
configured to decrease the first vent flow such that the second vent flow increases as
the membrane is deflected closer to the base due to sing the therapy re
above the threshold therapy pressure value, (f) the at least one first orifice may
comprise a plurality of inner orifices and the at least one second orifice may comprise
a plurality of outer orifices, (g) the base may comprise an inner base and an outer
base, (h) the vent system may comprise a plurality of membrane spacers extending
from the inner base, (i) the membrane may be supported over the plurality of inner
es on the outer base and the membrane spacers such that increasing the therapy
pressure above a threshold therapy pressure value causes the membrane to deflect
towards the inner base, (j) the membrane may be ured such that a membraneinner
base gap defined between the membrane and the inner base decreases as the
therapy pressure is increased above the threshold therapy pressure value, (k) the
membrane may be ured such that as the membrane-inner base gap decreases the
first vent flow decreases and the second vent flow increases, (l) the membrane may
comprise an elastically deformable material, (m) the elastically deformable al
may comprise silicone, (n) the vent housing may be formed from a single,
homogeneous piece of a relatively rigid material, (o) the relatively rigid material may
be rbonate, (p) the outer wall, the inner wall, the inner base, the outer base, and
the ne may be circular, (q) the outer wall, the inner wall, the inner base, the
outer base, and the membrane may be concentric, and/or (r) the membrane may not be
attached to the vent housing such that the membrane is freely movable towards and
away from the base.
Another aspect of the t technology is directed to a patient interface
comprising: a seal-forming structure; a plenum chamber joined to the seal-forming
ure; a positioning and ising ure to secure the patient interface on the
patient in use; and the vent system according to any of the aspects and/or examples
disclosed in the two immediately preceding paragraphs. The t interface may
comprise a vent connector tube or a ling structure to fluidly t the vent
system to the plenum chamber.
Another aspect of the present technology is directed to a patient interface
that may comprise: a plenum chamber pressurisable to a therapeutic pressure of at
least 6 cmH2O above ambient air pressure, said plenum chamber including a plenum
chamber inlet port sized and structured to receive a flow of air at the therapeutic
pressure for breathing by a patient; a seal-forming structure constructed and arranged
to form a seal with a region of the patient’s face surrounding an entrance to the
patient’s airways such that the flow of air at said therapeutic pressure is red to at
least an entrance to the patient’s nares, the orming structure constructed and
arranged to maintain said therapeutic re in the plenum chamber throughout the
patient’s respiratory cycle in use; a positioning and ising structure to e an
elastic force to hold the seal-forming structure in a therapeutically effective position
on the patient’s head, the positioning and ising structure comprising a tie, the tie
being constructed and arranged so that at least a portion overlies a region of the
patient’s head superior to an otobasion superior of the patient’s head in use, and a
portion of the tie being dimensioned and structured to engage in use a portion of the
patient’s head in a region of a al bone, wherein the oning and stabilising
structure has a non-rigid decoupling portion; and a vent system for use with a patient
interface during respiratory therapy of a t with a therapy flow of gas pressurized
above ambient pressure, the vent system ing a vent flow of gas to discharge gas
exhaled by the patient from a pressurized volume, the vent flow being continuous
during the respiratory y, the vent system comprising: a vent housing a base
having at least one first orifice extending through the base to allow gas to be
discharged to atmosphere from the pressurized volume; at least one second orifice to
allow gas to be discharged to atmosphere from the pressurized volume; and a
membrane positioned adjacent to the base, wherein the pressurized volume is in fluid
communication with atmosphere through the at least one first orifice and the at least
one second orifice throughout a therapeutic pressure range, wherein the membrane is
configured such that an increase in pressure within the pressurized volume causes the
membrane to ct a first vent flow through the at least one first orifice throughout
the therapeutic pressure range, and wherein restriction of the first vent flow through
the at least one first orifice causes an increase in a second vent flow through the at
least one second e such that the vent flow through the at least one first orifice
and the at least one second orifice is approximately constant throughout the
therapeutic re range, and wherein the patient interface is configured to allow the
patient to breath from ambient through their mouth in the absence of a flow of
pressurised air through the plenum chamber inlet port, or the patient interface is
configured to leave the patient’s mouth uncovered.
In examples, (a) the vent housing may comprise an outer wall and an inner
wall, the inner wall defining an inlet for the therapy flow of gas, and the base may be
positioned between the outer wall and the inner wall, (b) the t flow may be
greater than or equal to the sum of the first vent flow and the second vent flow, (c) the
membrane may be cally deformable toward the base in use such that the first
vent flow is restricted as the membrane is deflected s the base, (d) the
membrane may be configured to deflect closer to the base as the therapeutic pressure
increases above a threshold therapeutic pressure value, (e) the membrane may be
configured to decrease the first vent flow such that the second vent flow increases as
the membrane is deflected closer to the base due to increasing the therapeutic pressure
above the threshold therapeutic pressure value, (f) the base may comprise an inner
base and an outer base, (g) the at least one first orifice may se a plurality of
inner orifices and the at least one second orifice may comprise a plurality of outer
orifices, (h) the vent system may comprise a plurality of membrane spacers extending
from the inner base, (i) the membrane may be supported over the plurality of inner
orifices on the outer base and the membrane spacers, (j) the vent housing may
comprise a base divider between the inner base and the outer base and the membrane
may be ted over the plurality of inner orifices on the base divider and the
membrane spacers, (k) the outer base may comprise a ity of lateral membrane
supports that are configured to prevent the membrane from covering the plurality of
outer orifices, (l) the membrane may comprise an elastically deformable material, (m)
the elastically able material may se silicone, (n) the vent housing may
be formed from a single, homogeneous piece of a relatively rigid material, (o) the
relatively rigid material may be polycarbonate, (p) the outer wall, the inner wall, the
inner base, the outer base, and the membrane may be circular, (q) the outer wall, the
inner wall, the inner base, the outer base, and the membrane may be concentric, (r) the
membrane may not be attached to the vent housing such that the membrane is freely
movable towards and away from the base, and/or (s) the patient interface may
comprise a vent connector tube or a decoupling structure to fluidly connect the vent
system to the plenum chamber.
Another aspect of the present technology is directed to a patient interface
that may se: a plenum chamber pressurisable to a therapeutic pressure of at
least 6 cmH2O above t air pressure, said plenum chamber including a plenum
chamber inlet port sized and structured to receive a flow of air at the eutic
pressure for breathing by a patient; a seal-forming structure constructed and arranged
to form a seal with a region of the patient’s face surrounding an entrance to the
patient’s airways such that the flow of air at said therapeutic re is delivered to at
least an entrance to the patient’s nares, the seal-forming structure constructed and
arranged to maintain said therapeutic pressure in the plenum chamber throughout the
patient’s respiratory cycle in use; a positioning and stabilising structure to provide an
elastic force to hold the seal-forming structure in a eutically effective position
on the patient’s head, the positioning and stabilising structure comprising a tie, the tie
being constructed and arranged so that at least a portion overlies a region of the
patient’s head superior to an otobasion superior of the patient’s head in use, and a
portion of the tie being dimensioned and structured to engage in use a n of the
patient’s head in a region of a parietal bone, n the positioning and stabilising
structure has a non-rigid decoupling portion; and a vent system to provide a vent flow
of gas to discharge gas exhaled by the patient from a pressurized volume, the vent
flow being continuous during the respiratory therapy, the vent flow comprising a first
vent flow and a second vent flow, the vent system comprising: a vent housing
comprising a base having at least one first orifice extending through the base for the
first vent flow; at least one second orifice for the second vent flow; and a membrane
positioned adjacent to the base, wherein the pressurized volume is in fluid
ication with atmosphere through the at least one first orifice and the at least
one second orifice throughout a therapeutic pressure range, wherein the membrane is
configured to be elastically deformed by pressure within the pressurized volume such
that increased ation due to sed pressure decreases the first vent flow
through the at least one first e and increases the second vent flow through the at
least one second orifice to in a substantially constant vent flow throughout the
therapeutic pressure range, and wherein the patient interface is configured to allow the
patient to breath from ambient through their mouth in the absence of a flow of
pressurised air through the plenum chamber inlet port, or the patient interface is
configured to leave the patient’s mouth uncovered.
In es, (a) the vent housing may comprise an outer wall and an inner
wall, the inner wall defining an inlet for the therapy flow of gas, and the base may be
positioned between the outer wall and the inner wall, (b) the washout flow may be
greater than or equal to the sum of the first vent flow and the second vent flow, (c) the
membrane may be cally deformable toward the base in use such that the first
vent flow is restricted as the membrane is deflected towards the base, (d) the
membrane may be configured to deflect closer to the base as the therapeutic pressure
increases above a threshold therapeutic re value, (e) the membrane may be
configured to decrease the first vent flow such that the second vent flow increases as
the membrane is ted closer to the base due to sing the therapeutic pressure
above the threshold therapeutic pressure value, (f) the base may comprise an inner
base and an outer base, (g) the at least one first orifice may comprise a plurality of
inner orifices and the at least one second orifice may comprise a plurality of outer
orifices, (h) the vent system may comprise a plurality of membrane spacers extending
from the inner base, (i) the membrane may be supported over the plurality of inner
es on the outer base and the membrane spacers, (j) the vent housing may
comprise a base divider between the inner base and the outer base and the membrane
may be supported over the plurality of inner es on the base divider and the
membrane spacers, (k) the outer base may comprise a plurality of l membrane
supports that are configured to prevent the membrane from covering the plurality of
outer orifices, (l) the membrane may comprise an elastically deformable material, (m)
the elastically deformable material may comprise silicone, (n) the vent housing may
be formed from a single, homogeneous piece of a relatively rigid material, (o) the
relatively rigid material may be polycarbonate, (p) the outer wall, the inner wall, the
inner base, the outer base, and the membrane may be circular, (q) the outer wall, the
inner wall, the inner base, the outer base, and the membrane may be tric, (r) the
membrane may not be attached to the vent housing such that the membrane is freely
movable s and away from the base, and/or (s) the t interface may
comprise a vent connector tube or a decoupling structure to fluidly connect the vent
system to the plenum chamber.
Another aspect of the present technology is ed to a vent ly for
a respiratory pressure therapy (RPT) system to provide a flow of pressurized gas at a
therapeutic pressure of at least 6 cmH2O above ambient air pressure from a
respiratory pressure therapy (RPT) device to a patient interface to treat a respiratory
disorder. The vent assembly comprises: a vent housing having a first orifice
configured to receive the flow of pressurized gas from the RPT device and the vent
g having a plurality of holes to discharge pressurized gas to atmosphere; a vent
g connector having a second orifice; a tube connected to the vent housing
tor at the second orifice, the tube being configured to be connected to the
patient ace to direct the flow of pressurized gas to the patient interface; and a
heat and moisture exchanger (HME) comprising an HME housing and an HME
material within the HME housing, wherein the vent housing and the vent g
connector are configured to be connected to, at least in part, form a cavity, and
wherein the HME is positioned in the cavity when the vent assembly is assembled.
Another aspect of the present technology is directed to an RPT system.
The RPT system comprising: a vent assembly; an RPT device configured to generate
the flow of rized gas; a patient interface configured to deliver the flow of
pressurized gas to the patient’s s, the patient interface being non-vented; and a
ry conduit ured to deliver the flow of pressurized gas from the RPT
device to the vent assembly.
In examples of the vent assembly and the RPT system described in the
two preceding paragraphs, (a) the vent assembly may further comprise an annular lip
extending from around an inner periphery of the vent housing and at least one
retaining protrusion extending from the annular lip, (b) the vent ly may further
comprise an annular recess extending around an outer periphery of the HME housing,
and the at least one retaining protrusion and the annular recess may be configured to
removably connect the HME housing to the vent housing, (c) the HME g may
be removably connected to the vent housing with a snap-fit, (d) the HME housing
may comprise a patient-side HME housing portion and an atmosphere-side HME
housing portion, and the vent assembly may be configured such that the patient-side
HME housing portion is positioned closer to the patient than the atmosphere-side
HME housing portion in use, (e) the annular recess may be provided to the
atmosphere-side HME housing portion, (f) the vent g may further comprise an
annular surface around the first orifice and the plurality of holes pass through the
annular surface, and the vent assembly may comprise a membrane positioned adjacent
to the r surface, and the membrane may be movable such that the membrane is
urged t the annular surface of the vent housing as the pressure of the
rized gas within the vent assembly increases, (g) the plurality of holes may
comprise a first group of holes and a second group of holes, the first group of holes
being proximal to the first orifice relative to the second group of holes, (h) the
membrane may be shaped and dimensioned such that the membrane does not cover
the first group of holes, (i) the membrane may be structured to cover more of the
second group of holes as the pressure of the pressurized gas within the vent assembly
increases, (j) the first group of holes may be positioned upstream of the second group
of holes relative to the flow of pressurized gas, (k) the vent assembly may further
comprise a retaining structure to retain the membrane in a position adjacent to the
annular surface of the vent g, (l) the membrane may r comprise an elastic
material, (m) each of the plurality of holes may have a shape that converges from an
internal surface of the vent housing to an external surface of the vent housing, (n) the
HME, including the HME housing and the HME material, may be removable from the
cavity, and/or (o) the respiratory therapy system may not include a humidifier.
Another aspect of the present technology is ed to a vent system for
use with a patient interface during respiratory therapy of a patient with a y flow
of gas pressurized above ambient pressure, the vent system providing a vent flow of
gas to discharge gas exhaled by the patient from a pressurized volume, the vent flow
of gas being continuous during the respiratory therapy. The vent system comprises: a
vent g comprising a base having at least one first orifice extending through the
base to allow gas to be discharged to atmosphere from the pressurized volume; at least
one second e to allow gas to be discharged to atmosphere from the pressurized
volume; a vent housing tor having a second orifice configured to direct the
therapy flow of gas to the patient interface; a heat and moisture exchanger (HME)
comprising an HME housing and an HME material within the HME g; and a
membrane oned adjacent to the base, wherein the vent housing and the vent
housing tor are ured to be connected to, at least in part, form a cavity,
and wherein the HME is positioned in the cavity when the vent system is assembled,
wherein the pressurized volume is in fluid communication with atmosphere through
the at least one first orifice and the at least one second orifice throughout a therapeutic
pressure range, and wherein the membrane is elastically deformable due to re
within the pressurized volume to apportion the vent flow of gas between the at least
one first orifice and the at least one second orifice throughout the therapeutic pressure
range.
Another aspect of the t technology is ed to patient interface.
The patient interface comprises: a seal-forming structure; a plenum chamber joined to
the seal-forming structure; a positioning and ising structure to secure the patient
interface on the patient in use; and a vent system.
In examples of the vent system and the patient interface described in the
two preceding paragraphs, (a) the vent system may further comprise an annular lip
ing from around an inner periphery of the vent housing and at least one
ing protrusion extending from the annular lip, (b) the vent system may further
comprise an annular recess extending around an outer ery of the HME housing,
and the at least one retaining protrusion and the annular recess may be configured to
removably connect the HME housing to the vent housing, (c) the HME housing may
be removably connected to the vent housing with a snap-fit, (d) the HME g
may comprise a patient-side HME housing portion and an atmosphere-side HME
housing portion, and vent assembly may be configured such that the patient-side
HME housing portion is positioned closer to the patient than the atmosphere-side
HME housing portion in use, (e) the annular recess may be provided to the
here-side HME housing portion, (f) the vent housing may comprise an outer
wall and an inner wall, the inner wall defining an inlet for the y flow of gas, and
the base may be positioned n the outer wall, the inner wall, and the base, (g)
the base may further comprise an inner base and an outer base, (h) the outer base may
be adjacent to the outer wall, the inner base is adjacent to the outer base, and the inner
base is adjacent to the inner wall, (i) the at least one first orifice may further comprise
a plurality of inner orifices and the at least one second orifice may further comprise a
ity of outer orifices, (j) the plurality of outer orifices may pass through the outer
base and the plurality of inner orifices may pass between the outer base and the inner
base, (k) the membrane may comprise an elastically deformable material, (l) the
elastically deformable material may comprise silicone, (m) the vent housing may be
formed from a single, homogeneous piece of a relatively rigid material, (n) the
relatively rigid material may be polycarbonate, (o) the outer wall, the inner wall, the
inner base, the outer base, and the membrane may be circular, (p) the outer wall, the
inner wall, the inner base, the outer base, and the membrane may be concentric, (q)
the membrane may not be attached to the vent housing such that the membrane is
freely movable towards and away from the base, (r) the vent system may further
comprise a vent connector tube or a decoupling structure to fluidly connect the vent
system to the plenum chamber, and/or (s) the HME, including the HME housing and
the HME material, may be removable from the cavity.
Of course, portions of the aspects may form sub-aspects of the present
technology. Also, various ones of the sub-aspects and/or aspects may be combined in
various manners and also constitute additional aspects or sub-aspects of the present
technology.
Other features of the technology will be apparent from consideration of
the information contained in the following detailed description, abstract, drawings and
claims.
4 BRIEF PTION OF THE DRAWINGS
The present technology is illustrated by way of example, and not by way
of limitation, in the figures of the accompanying drawings, in which like reference
numerals refer to similar ts including:
4.1 TREATMENT S
Fig. 1A shows a system including a patient 1000 wearing a patient
interface 3000, in the form of a nasal pillows, receiving a supply of air at ve
pressure from an RPT device 4000. Air from the RPT device is humidified in a
humidifier 5000, and passes along an air circuit 4170 to the t 1000. A bed
partner 1100 is also shown.
Fig. 1B shows a system ing a patient 1000 wearing a patient
interface 3000, in the form of a nasal mask, receiving a supply of air at positive
pressure from an RPT device 4000. Air from the RPT device is humidified in a
humidifier 5000, and passes along an air circuit 4170 to the t 1000.
Fig. 1C shows a system including a patient 1000 wearing a patient
interface 3000, in the form of a full-face mask, receiving a supply of air at positive
pressure from an RPT device 4000. Air from the RPT device is fied in a
humidifier 5000, and passes along an air t 4170 to the patient 1000.
4.2 RESPIRATORY SYSTEM AND FACIAL Y
Fig. 2A shows an overview of a human respiratory system including the
nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, us, lung,
alveolar sacs, heart and diaphragm.
Fig. 2B shows a view of a human upper airway including the nasal cavity,
nasal bone, lateral nasal cartilage, greater alar age, nostril, lip superior, lip
or, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds,
oesophagus and trachea.
Fig. 2C is a front view of a face with several features of surface y
identified including the lip superior, upper vermilion, lower vermilion, lip inferior,
mouth width, endocanthion, a nasal ala, bial sulcus and cheilion. Also indicated
are the directions superior, inferior, radially inward and radially outward.
Fig. 2D is a side view of a head with several features of surface y
identified ing glabella, sellion, pronasale, subnasale, lip superior, lip inferior,
supramenton, nasal ridge, alar crest point, otobasion superior and otobasion inferior.
Also indicated are the directions superior & inferior, and anterior & posterior.
Fig. 2E is a further side view of a head. The approximate locations of the
Frankfort horizontal and bial angle are indicated. The coronal plane is also
indicated.
Fig. 2F shows a base view of a nose with several features identified
ing naso-labial sulcus, lip inferior, upper Vermilion, naris, subnasale,
columella, pronasale, the major axis of a naris and the sagittal plane.
Fig. 2G shows a side view of the superficial features of a nose.
Fig. 2H shows subcutaneal structures of the nose, including lateral
age, septum cartilage, greater alar cartilage, lesser alar cartilage, sesamoid
cartilage, nasal bone, epidermis, adipose tissue, frontal process of the maxilla and
fibrofatty tissue.
Fig. 2I shows a medial dissection of a nose, approximately several
millimeters from a sagittal plane, amongst other things showing the septum cartilage
and medial crus of greater alar cartilage.
Fig. 2J shows a front view of the bones of a skull including the frontal,
nasal and zygomatic bones. Nasal concha are indicated, as are the maxilla, and
mandible.
Fig. 2K shows a lateral view of a skull with the outline of the surface of a
head, as well as several muscles. The ing bones are shown: frontal, sphenoid,
nasal, zygomatic, maxilla, le, parietal, temporal and occipital. The mental
protuberance is indicated. The ing muscles are shown: digastricus, masseter,
cleidomastoid and trapezius.
Fig. 2L shows an anterolateral view of a nose.
4.3 PATIENT INTERFACE
Fig. 3A shows a patient interface in the form of a nasal mask in
accordance with one form of the present technology.
Fig. 3B shows a schematic of a cross-section through a structure at a
point. An outward normal at the point is indicated. The curvature at the point has a
positive sign, and a relatively large magnitude when compared to the magnitude of the
curvature shown in Fig. 3C.
Fig. 3C shows a tic of a cross-section through a structure at a
point. An outward normal at the point is indicated. The curvature at the point has a
positive sign, and a relatively small magnitude when compared to the magnitude of
the ure shown in Fig. 3B.
Fig. 3D shows a tic of a section through a structure at a
point. An outward normal at the point is indicated. The curvature at the point has a
value of zero.
Fig. 3E shows a schematic of a cross-section through a structure at a
point. An outward normal at the point is indicated. The curvature at the point has a
negative sign, and a vely small magnitude when compared to the magnitude of
the curvature shown in Fig. 3F.
Fig. 3F shows a schematic of a cross-section through a structure at a point.
An outward normal at the point is indicated. The curvature at the point has a negative
sign, and a relatively large magnitude when compared to the magnitude of the
curvature shown in Fig. 3E.
Fig. 3G shows a cushion for a mask that includes two pillows. An exterior
surface of the cushion is indicated. An edge of the surface is indicated. Dome and
saddle regions are indicated.
Fig. 3H shows a cushion for a mask. An exterior surface of the n is
indicated. An edge of the surface is ted. A path on the surface between points A
and B is indicated. A straight line ce between A and B is indicated. Two saddle
regions and a dome region are ted.
4.4 RPT DEVICE
Fig. 4A shows an RPT device in accordance with one form of the present
technology.
Fig. 4B is a schematic diagram of the pneumatic path of an RPT device in
accordance with one form of the present technology. The directions of upstream and
downstream are indicated.
Fig. 4C is a schematic diagram of the electrical components of an RPT
device in ance with one form of the present technology.
Fig. 4D is a schematic diagram of the thms implemented in an RPT
device in accordance with one form of the present technology.
Fig. 4E is a flow chart illustrating a method carried out by the therapy
engine module of Fig. 4D in accordance with one form of the present technology.
4.5 HUMIDIFIER
Fig. 5A shows an isometric view of a humidifier in accordance with one
form of the present technology.
Fig. 5B shows an isometric view of a humidifier in accordance with one
form of the present technology, showing a humidifier reservoir 5110 removed from
the humidifier reservoir dock 5130.
Fig. 5C shows a schematic of a humidifier in accordance with one form of
the present technology.
4.6 VENT ADAPTOR
Fig. 6A shows a side view of a fluid connector with a first end and a
second end mated with one another.
Fig. 6B shows a side, cross-sectional view of a fluid connector with a first
end and a second end disengaged from one another.
Fig. 6C shows a side, cross-sectional view of a fluid connector with a first
end and a second end mated with one r.
Fig. 6D shows a ctive view of a fluid connector with a first end and
a second end separated from one another with an interior of the first end being visible.
Fig. 6E shows a cross-sectional view of a fluid connector with an
additional fluid port.
Fig. 6F shows a fluid connector with a first end and a second end
connected together and the first end integrated into an RTP .
Fig. 6G shows a fluid connector with a first end and a second end
disconnected and the first end integrated into an RTP device
Fig. 6H shows a ctive view of a fluid connector with a first end and
a second end ted from one another with the sealing surface of the second end
being visible.
Fig. 7A shows a perspective view of a vent adaptor according to an
example of the present technology.
Fig. 7B shows a side view of a vent adaptor according to an e of
the present technology.
Fig. 7C shows a top view of a vent adaptor according to an example of the
present technology.
Fig. 7D shows a cross-section view of a vent adaptor according to an
example of the present technology taken through line 7D-7D of Fig. 7C.
Fig. 7E shows an exploded view of a vent adaptor according to an
example of the present technology.
Fig. 7F shows another ed view of a vent adaptor according to an
example of the present technology.
Fig. 8A shows a perspective view of a vent housing according to an
example of the present technology.
Fig. 8B shows another perspective view of a vent housing according to an
example of the present technology.
Fig. 8C shows a side view of a vent housing according to an example of
the present technology.
Fig. 8D shows another side view of a vent housing according to an
example of the present technology.
Fig. 8E shows a top view of a vent housing ing to an e of the
present technology.
Fig. 8F shows a cross-section view of a vent housing ing to an
example of the present technology taken through line 8F-8F of Fig. 8E.
Fig. 9A shows a perspective view of a vent housing tor according
to an example of the present technology.
Fig. 9B shows another perspective view of a vent housing connector
ing to an e of the present logy.
Fig. 9C shows a side view of a vent housing connector according to an
example of the present technology.
Fig. 9D shows another side view of a vent housing connector ing to
an example of the present technology.
Fig. 9E shows a top view of a vent housing connector according to an
example of the present technology.
Fig. 10A shows a perspective view of a bellows seal according to an
example of the present technology.
Fig. 10B shows another perspective view of a bellows seal according to an
example of the present technology.
Fig. 10C shows a side view of a bellows seal according to an example of
the present technology.
Fig. 10D shows another side view of a bellows seal according to an
example of the present technology.
Fig. 10E shows a bottom view of a bellows seal according to an example
of the present logy.
Fig. 11A shows a perspective view of a vent adaptor connector according
to an example of the t technology.
Fig. 11B shows another perspective view of a vent adaptor connector
according to an example of the t technology.
Fig. 11C shows a side view of a vent adaptor connector according to an
example of the present technology.
Fig. 11D shows r side view of a vent adaptor connector ing
to an example of the present logy.
Fig. 11E shows a bottom view of a vent adaptor connector according to an
example of the present technology.
Fig. 12A shows a perspective view of a heat and moisture exchanger
(HME) clip according to an example of the present technology.
Fig. 12B shows a side view of a heat and moisture exchanger (HME) clip
according to an example of the t technology.
Fig. 12C shows another side view of a heat and moisture exchanger
(HME) clip according to an example of the present technology.
Fig. 12D shows another side view of a heat and moisture exchanger
(HME) clip according to an example of the present technology.
Fig. 13A shows a perspective view of a heat and moisture ger
(HME) housing according to an e of the present technology.
Fig. 13B shows a side view of a heat and moisture exchanger (HME)
housing according to an example of the present technology.
Fig. 13C shows another side view of a heat and moisture exchanger
(HME) housing according to an example of the present technology.
Fig. 13D shows a top view of a heat and moisture exchanger (HME)
housing according to an example of the present technology.
Fig. 14A shows a perspective view of a conduit connector ing to an
example of the present technology.
Fig. 14B shows a top view of a t connector according to an
example of the present technology.
Fig. 14C shows a side view of a conduit connector according to an
example of the t logy.
Fig. 14D shows a front view of a conduit connector according to an
example of the present technology.
Fig. 15A shows a perspective view of a vent adaptor according to an
example of the present technology.
Fig. 15B shows another perspective view of a vent adaptor according to
an example of the t technology.
Fig. 15C shows an exploded view of a vent adaptor according to an
example of the present technology.
Fig. 15D shows an exploded view of a vent adaptor according to an
example of the present technology.
Fig. 15E shows a side view of a vent adaptor according to an example of
the present technology.
Fig. 15F shows a cross-section view of a vent adaptor ing to an
example of the present technology taken through line 15F-15F of Fig. 15B.
Fig. 16 shows a graph of vent flow from a full face mask compared to
vent flow from a constant flow vent (CFV) according to the present technology over a
range of therapeutic pressures.
Fig. 17 shows a diagram of a t receiving y according to an
example of the present logy.
Fig. 18 shows a graph of vent flow from a full face mask compared to
vent flow from a constant flow vent (CFV) according to the present technology over a
range of therapeutic pressures.
Fig. 19 shows a graph of vent flow from a constant flow vent (CFV) only,
from a passive vent only, and a combination of both according to the present
technology over a range of therapeutic pressures.
Fig. 20 shows an example of a nt flow vent (CFV) membrane
ing to an example of the present technology.
Fig. 21A shows a cross-section view of a vent adaptor according to an
example of the t technology.
Fig. 21B shows an exploded view of a constant flow vent (CFV) of a vent
adaptor according to an e of the present technology.
Fig. 21C shows a rear view of a constant flow vent (CFV) of a vent
adaptor according to an example of the present technology.
Fig. 21D shows a perspective view of a constant flow vent (CFV) of a
vent adaptor according to an example of the present logy.
Fig. 21E shows another perspective view of a constant flow vent (CFV) of
a vent r according to an example of the present technology.
Fig. 21F shows a cross-section view of a constant flow vent (CFV) of a
vent r according to an example of the present technology.
Fig. 22 shows an exploded view of a vent adaptor according to an
example of the present technology.
Fig. 23 shows a chart of exemplary patient interfaces according to the
present technology.
Fig. 24A shows a cross-section view of a vent adaptor according to an
example of the present technology.
Fig. 24B shows a perspective view of a vent adaptor according to an
e of the present technology.
Fig. 25A shows a cross sectional view of a HME 7000 comprising a
single layer 7001 in accordance with one aspect of the present technology.
Fig. 25B shows examples of a single corrugation 7030 of a HME 7000 in
accordance with one aspect of the present technology.
Fig 25C is a tic diagram showing a HME 7000 comprising a
plurality of layers 7001 stacked along both a al and horizontal axis.
Fig 25D is a diagram that illustrates a HME under preload to compress the
corrugations in a fixed volume such that the number of layers 7001 is increased within
the fixed volume.
Fig. 25E displays a corrugated structure 7002 comprising a plurality of
corrugations 7030, n the ated structure is rolled to form a HME 7000.
Fig. 26 depicts orifices, a diffusing member and a blocking member that
form part of a gas washout vent.
Fig. 27 depicts orifices, a diffusing member and a blocking member that
form part of a gas washout vent where holes are provided in the blocking member.
Fig. 28 depicts an exploded view of orifices, a diffusing member and a
blocking member that form part of a gas washout vent formed circularly about a
central hole.
Fig. 29 depicts a simplified view of orifices, a diffusing member and a
ng member that form part of a gas washout vent formed circularly about a
central hole.
Fig. 30 s a cross-sectional view taken through line 30-30 of Fig. 29.
Fig. 31A depicts a partial view of an elbow with a gas washout vent with
one annular outlet.
Fig. 31B s an axial view of orifices in the gas washout vent of Fig.
Fig. 31C depicts a cross-sectional view taken h the plane of the
drawing of Fig. 31, which is equivalent to the plane labelled 31C-31C in Fig. 31B.
Fig. 32A depicts an elbow with a ball and socket joint and gas washout
vent.
Fig. 32B depicts an exploded view of the elbow of Fig. 32A.
Fig. 32C depicts a side view of the elbow.
Fig. 32D depicts a cross-sectional view taking through line D of
Fig. 32C.
Fig. 33A depicts a perspective view of a vent r according to an
example of the present technology.
Fig. 33B depicts another perspective view of a vent adaptor according to
an example of the present technology.
Fig. 33C depicts a superior view of a vent adaptor according to an
example of the present technology.
Fig. 33D depicts an or view of a vent adaptor according to an
example of the present technology.
Fig. 33E depicts a lateral view of a vent adaptor according to an example
of the present technology.
Fig. 33F depicts a cross-sectional view of a vent adaptor taken through
line 33F-33F of Fig. 33C according to an example of the present technology.
Fig. 33G depicts a cross-sectional view of a vent adaptor with a heat and
moisture exchanger (HME) housing taken through line 33F-33F of Fig. 33C
according to an example of the present technology.
Fig. 33H s a cross-sectional view of a vent r with a heat and
moisture exchanger (HME) g taken through line F of Fig. 33C
according to an example of the present technology.
Fig. 33I depicts an exploded view of a vent adaptor according to an
example of the present technology.
Fig. 34A depicts a perspective view of a vent assembly for a vent r
according to an example of the present technology.
Fig. 34B depicts another perspective view of a vent assembly for a vent
adaptor according to an example of the present technology.
Fig. 34C depicts a posterior view of a vent assembly for a vent r
according to an example of the present technology.
Fig. 34D depicts an anterior view of a vent ly for a vent adaptor
according to an example of the present technology.
Fig. 34E depicts a lateral view of a vent assembly for a vent r
ing to an example of the present technology.
Fig. 34F s a cross-sectional view of a vent assembly for a vent
adaptor taken through line 34F-34F of Fig. 34C according to an example of the
present technology.
Fig. 34G s an exploded view of a vent assembly for a vent adaptor
according to an example of the present technology.
Fig. 35 depicts a perspective view of a vent adaptor with a patient
interface according to an e of the present technology.
Fig. 36A depicts a perspective view of an air circuit according to an
example of the present technology.
Fig. 36B depicts another perspective view of an air circuit ing to an
e of the present technology.
Fig. 36C depicts an exploded view of an air circuit according to an
example of the present technology.
Fig. 37A depicts a ctive view of a vent adaptor according to an
example of the present technology.
Fig. 37B depicts another perspective view of a vent adaptor according to
an example of the present technology.
Fig. 37C depicts a lateral view of a vent r according to an example
of the present technology.
Fig. 37D depicts a cross-sectional view of a vent adaptor taken through
line 37D-37D of Fig. 37B according to an example of the t technology.
Fig. 37E depicts an exploded view of a vent r according to an
example of the present technology.
Fig. 38A depicts a perspective view of a heat and moisture exchanger
(HME) housing according to an example of the present technology.
Fig. 38B depicts another perspective view of a HME housing according to
an example of the present technology.
Fig. 38C depicts an exploded view of a HME housing according to an
e of the present technology.
Fig. 39A depicts a perspective view of a heat and moisture exchanger
(HME) housing according to an example of the present technology.
Fig. 39B s another perspective view of a HME housing according to
an example of the t technology.
Fig. 39C depicts an exploded view of a HME housing according to an
example of the present logy.
Fig. 40 depicts a perspective view of a vent adaptor with a patient
interface according to an example of the present technology.
Fig. 41 depicts a perspective view of a vent adaptor with a patient
interface according to an e of the present technology.
A shows a top perspective view of a vent housing according to
another example of the present technology.
B shows a top view of a vent housing according to another
example of the present technology.
C shows a bottom view of a vent housing ing to another
example of the present technology.
D shows a bottom perspective view of a vent housing according to
another example of the present technology.
E shows a side view of a vent housing according to another
example of the t technology.
F shows a cross-sectional view of a vent g according to
r example of the present technology taken through line 42F-42F of B.
G shows a cross-sectional view of a vent housing according to
another example of the present technology taken through line 42G-42G of B.
A shows a top perspective view of a vent system according to
another example of the present technology.
B shows a top view of a vent system according to another example
of the present technology.
C shows a bottom view of a vent system according to another
example of the present technology.
D shows a bottom perspective view of a vent system according to
another example of the present logy.
E shows a side view of a vent system according to another
example of the present technology.
F shows a cross-sectional view of a vent system according to
another example of the present technology taken through line 43F-43F of B.
G shows a cross-sectional view of a vent system according to an
example of the t technology taken through line 43G-43G of B.
DETAILED PTION OF EXAMPLES OF THE
TECHNOLOGY
Before the present technology is described in further detail, it is to be
understood that the logy is not limited to the particular examples described
, which may vary. It is also to be tood that the terminology used in this
disclosure is for the e of describing only the particular examples discussed
herein, and is not intended to be limiting.
The following ption is provided in relation to various examples
which may share one or more common characteristics and/or features. It is to be
understood that one or more features of any one example may be combinable with one
or more features of another example or other examples. In addition, any single
feature or combination of features in any of the es may constitute a further
example.
.1 THERAPY
In one form, the present technology comprises a method for treating a
respiratory disorder comprising the step of applying positive pressure to the entrance
of the airways of a patient 1000.
In certain examples of the present technology, a supply of air at positive
pressure is provided to the nasal passages of the patient via one or both nares.
In certain examples of the present technology, mouth breathing is limited,
restricted or prevented.
.2 TREATMENT SYSTEMS
In one form, the present technology comprises an apparatus or device for
treating a respiratory disorder. The tus or device may comprise an RPT device
4000 for supplying pressurised air to the patient 1000 via an air circuit 4170 to a
patient interface 3000.
.3 PATIENT INTERFACE
A non-invasive patient interface 3000 in accordance with one aspect of
the present technology ses the following functional aspects: a seal-forming
structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300, a
vent 3400, one form of connection port 3600 for tion to air t 4170, and a
ad support 3700. In some forms a functional aspect may be provided by one or
more al components. In some forms, one physical component may provide one
or more functional aspects. In use the orming structure 3100 is arranged to
surround an entrance to the airways of the t so as to facilitate the supply of air at
positive pressure to the airways.
.3.1 Seal-forming structure
In one form of the present technology, a seal-forming structure 3100
provides a seal-forming e, and may additionally provide a cushioning function.
A seal-forming structure 3100 in accordance with the present logy
may be constructed from a soft, flexible, resilient material such as silicone.
In one form, the orming structure 3100 comprises a sealing flange
and a support flange. The sealing flange comprises a relatively thin member with a
thickness of less than about 1mm, for example about 0.25mm to about 0.45mm, that
extends around the perimeter of the plenum chamber 3200. Support flange may be
relatively thicker than the sealing flange. The support flange is disposed between the
sealing flange and the marginal edge of the plenum chamber 3200, and extends at
least part of the way around the perimeter. The support flange is or includes a like
element and functions to support the sealing flange from buckling in use. In use
the sealing flange can readily respond to system pressure in the plenum chamber 3200
acting on its underside to urge it into tight sealing engagement with the face.
In one form the seal-forming portion of the non-invasive patient interface
3000 comprises a pair of nasal puffs, or nasal pillows, each nasal puff or nasal pillow
being constructed and arranged to form a seal with a respective naris of the nose of a
patient.
Nasal pillows in accordance with an aspect of the present technology
include: a frusto-cone, at least a n of which forms a seal on an underside of the
patient's nose, a stalk, a le region on the underside of the frusto-cone and
connecting the frusto-cone to the stalk. In addition, the structure to which the nasal
pillow of the present logy is ted includes a flexible region adjacent the
base of the stalk. The flexible regions can act in concert to facilitate a universal joint
structure that is accommodating of relative movement both displacement and angular
of the frusto-cone and the structure to which the nasal pillow is connected. For
example, the frusto-cone may be y ced towards the structure to which the
stalk is connected.
In one form, the non-invasive patient ace 3000 comprises a sealforming
portion that forms a seal in use on an upper lip region (that is, the lip
superior) of the patient's face.
In one form the non-invasive patient interface 3000 comprises a rming
portion that forms a seal in use on a chin-region of the patient's face.
.3.2 Plenum r
The plenum chamber 3200 has a perimeter that is shaped to be
complementary to the e contour of the face of an average person in the region
where a seal will form in use. In use, a marginal edge of the plenum chamber 3200 is
positioned in close proximity to an adjacent surface of the face. Actual contact with
the face is provided by the seal-forming structure 3100. The orming structure
3100 may extend in use about the entire perimeter of the plenum chamber 3200.
.3.3 oning and stabilising structure
The seal-forming structure 3100 of the patient interface 3000 of the
present technology may be held in sealing position in use by the positioning and
stabilising structure 3300.
In one form of the present technology, a positioning and stabilising
ure 3300 is provided that is configured in a manner consistent with being worn
by a patient while sleeping. In one example the positioning and stabilising structure
3300 has a low profile, or cross-sectional thickness, to reduce the ved or actual
bulk of the apparatus. In one example, the positioning and stabilising structure 3300
comprises at least one strap having a rectangular cross-section. In one example the
positioning and stabilising structure 3300 comprises at least one flat strap.
In one form of the present technology, a positioning and stabilising
structure 3300 comprises a strap constructed from a laminate of a fabric patientcontacting
layer, a foam inner layer and a fabric outer layer. In one form, the foam is
porous to allow moisture, (e.g., sweat), to pass through the strap. In one form, the
fabric outer layer comprises loop material to engage with a hook material portion.
In certain forms of the present technology, a positioning and stabilising
structure 3300 comprises a strap that is extensible, e.g. resiliently extensible. For
example the strap may be configured in use to be in tension, and to direct a force to
draw a cushion into sealing contact with a n of a patient’s face. In an example
the strap may be configured as a tie.
In certain forms of the t technology, a positioning and stabilising
structure 3300 comprises a strap that is le and e.g. gid. An advantage of
this aspect is that the strap is more comfortable for a patient to lie upon while the
patient is sleeping.
.3.4 Vent
In one form, the patient interface 3000 includes a vent 3400 constructed
and arranged to allow for the washout of exhaled gases, e.g. carbon dioxide.
One form of vent 3400 in ance with the present technology
comprises a plurality of holes, for example, about 20 to about 80 holes, or about 40 to
about 60 holes, or about 45 to about 55 holes.
The vent 3400 may be located in the plenum r 3200. Alternatively,
the vent 3400 is located in a decoupling structure, e.g., a swivel.
.3.5 ling structure(s)
In one form the patient ace 3000 includes at least one decoupling
structure, for example, a swivel or a ball and .
.3.6 Connection port
Connection port 3600 allows for connection to the air circuit 4170.
.3.7 Forehead support
In one form, the patient interface 3000 includes a forehead support 3700.
.3.8 Anti-asphyxia valve
In one form, the patient interface 3000 includes an anti-asphyxia valve.
.3.9 Ports
In one form of the present technology, a patient interface 3000 es
one or more ports that allow access to the volume within the plenum chamber 3200.
In one form this allows a clinician to supply supplemental oxygen. In one form, this
allows for the direct measurement of a property of gases within the plenum chamber
3200, such as the pressure.
.4 VENT ADAPTOR
.4.1 Constant Flow Vent
Figure 16 shows a comparison of vent flow rate between a regular vent
(FFM Nom Flow) versus the constant flow vent (CFV). The regular vent is a standard
moulded vent, e.g., a vent 3400 formed on the patient interface 3000 in Fig. 3A. As
can be seen in the graph, the vent flow rate is compared in a range of mask pressures
n 4-20 cm of H2O, which is a rd pressure range for Respiratory Pressure
y for SDB and OSA. As can be seen, the vent flow rate increases
logarithmically as the pressure ses. In comparison, the CFV shows a flatter
curve, where the vent flow rate appears more constant and lower over the same
pressure range.
Vent flow should be at least 16L/min to washout enough CO2 within the
system such that CO2 rebreathing is minimized by the patient. It has been shown that
a vent flow rate of between 20-27L/min is provides breathing comfort nt not
awakened due to increased CO2 rebreathing) and safety (avoid suffocation due to too
much CO2 rebreathing). One aspect of the present technology includes providing a
minimum (or minimum range) vent flow to ensure that sufficient CO2 is washed out.
Any vent flow above that minimum may be considered wastage. For example, when
viewing the graph shown in Fig. 16, the area between the CFV vent flow and FFM
Nom flow may be considered wasted flow. The CFV achieves the minimum vent flow
rate of 16L/min required within eutic pressure range and keeps this vent flow
rate n 16-27L/min within the pressure range of 4-20 cm of H20. In
comparison, the FFM Nom flow ranges from 22-55L/min. Thus, there may be greater
unnecessary flow loss using the FFM nom flow vent.
To compensate for unnecessary flow loss, the flow generator or RPT
device may be required to increase its flow to achieve the same pressure as compared
to the CFV. Thus, more power is required and a more complex flow generator is
required to allow for greater flow swings (e.g. n 16-55 L/min of vent flow) to
compensate for this vent. The CFV, however, may regulate the vent flow under
pressure changes to reduce the vent flow rate as re increases. Thus, the CFV
may allow for greater power savings by the flow generator and added simplicity due
to avoiding the need for x pressure/flow control.
A constant flow vent (CFV), according to the present technology, may be
a vent flow regulating valve (moveable membrane) 9140 that reacts to mask re
to regulate vent flow. An exemplary CFV is ed in Figs. F. The valve
9140 may be tuned such that the flow remains relatively constant within a
predetermined range of pressure. That is, when pressure increases in the mask/system,
the flap 9140 covers more internal vent holes 9126 to reduce the vent flow rate (vent
flow rate increases at higher pressures); when the re is low in the mask/system,
the flap 9140 covers fewer of the vent holes and allows more vent flow (compensates
for low vent flow rates at lower pressures). This tuning may allow for a substantially
constant vent flow within a range of pressures. The graph in Fig. 18 illustrates
changes in flow under changes in pressure with and without the CFV. The
performance of the exemplary CFV graphed in Fig. 18 has a flow rate of up to 24
L/min as pressure increases from 0-40 cm H2O.
According to an example of the present technology, the CFV may
comprise a moveable flap or a CFV membrane 9140 and may be made of elastic
material such as silicone or other TPE (thermoplastic elastomers). The flap 9140 may
be configured such that an increase in pressure in the mask urges the flap to cover
more of the internal vent holes 9126 and reduces the flow rate progressively. The flap
9140 may be oned perpendicular to the flow of pressurized gas flowing to the
patient. The vent passage of the al vent holes 9126 may also run perpendicularly
to the flow and away from the patient to exit to the atmosphere. The flap 9140 is
positioned such that pressure build up in the mask may urge the flap towards the
internal vent holes 9126.
Figure 21F shows the configuration of an exemplary CFV in cross
section. The CFV unit may be placed in line (that is within the air delivery conduit
circuit). As shown in Fig. 21F, if re builds up in the mask then the position of
the flap 9140 is such that the flap 9140 may move towards the internal vent holes
9126. The pressurized gas that s the internal vent holes 9126 that are not
blocked by the flap 9140 can then be vented to atmosphere via the external vent holes
9125.
The CFV is a feature that may allow for simplification of the RPT system.
Having a substantially constant vent flow rate within a range of pressures means that
the complexity of the flow generator or RPT device may be reduced as substantial
pressure control is no longer required to compensate for changing pressure loss due to
g. Moreover, the CFV may allow for reduced power consumption as power is
no longer required to sate for flow variations at different pressures. That is,
the CFV is passively (pressure driven) and is capable of regulating pressure due to
vent flow changes that would otherwise be actively compensated by changes in
pressure/flow ry from the RPT device. This simplification allows for a simpler
RPT device to deliver therapy, e.g., the device may have fewer parts, it may be
smaller, it may not require powered humidification, and/or it may require less power
overall to deliver therapy (due to the fact that it does not need to compensate for vent
flow changes). The CFV may also allow for e humidification via a heat and
moisture exchanger (HME), as described below.
A m with known CFV concepts is that there may be vent noise
associated when regulating the vent flow. It is le that there is some interaction
with the flap 9140 and the internal vent holes 9126 that disturbs vent flow and causes
noise. For example, it is hypothesized that the moveable flap 9140 does not fully
cover some of the internal vent holes 9126 when moving under pressure. This
interaction may cause turbulence and associated noise as gas flows between the flap
9140 and the internal vent hole 9126.
One way to reduce turbulence and, therefore, noise may be to reduce the
number of holes 9126 that interact with the flap 9140. However, a m vent flow
is required to t CO2 rebreathing in the mask and reducing the number of vent
holes 9126 that interact with the flap 9140 may not allow sufficient venting. Thus, a
solution according to the present technology may e having some of the vent
holes 9126 being ted by radial disc flap 9140 and other vent holes 9126 not
engaging with the flap 9140 and remaining open at all times. Having some vent holes
9126 open, i.e., the static vents, at all times means that the vent flow rate will increase
as pressure increases in the system, according to Bernoulli’s principle.
To compensate for this increase in vent flow rate such that the overall vent
flow is substantially constant over the eutic range of pressures, the vent flow of
the remaining vent holes, i.e., the regulated vents, may be reduced as pressure
increases. These vent holes 9126 may be regulated by the moveable flap 9140,
wherein the vent holes 9126 are covered progressively as the pressure increases,
thereby reducing the vent flow rate. The overall flow rate of the static vents can then
be averaged with the flow rate of the regulated vents to achieve an overall
substantially constant flow rate over a range of therapeutic pressures. The lower noise
levels of the vents can also be attributed to moulded vent technology that produces
low levels of noise as pressure and vent flow increases (e.g., by moulding small vent
holes with a converging profile). This technology in combination with the regulated
vent flow may allow for a low overall noise alternative for a constant flow vent.
A vent adaptor 9100 or fluid connector may comprise a constant flow vent
(CFV) unit. The CFV unit may comprise: a CFV ring 9150; a flat, annular valve
9140; and a vent housing 9120. The CFV ring 9150 may hold the valve 9140 in place
against the vent holes 9126. The vent housing 9120 may se an annular surface
comprising a plurality of vent holes 9126. The annular surface may comprise a central
orifice for ng the flow of pressurised gas into the mask chamber (inlet flow).
The r surface may comprise the plurality of vent holes 9126 to allow vent flow.
The valve 9140 may be adjacent to the vent holes 9126 and may be held freely
between i.e., ched between, the CFV ring 9150 and the annular surface of the
vent housing 9120, i.e., the flap 9140 is not fixed to CFV ring 9150 or the vent
g 9120. As mask re increases, this increases pressure towards the vent,
wherein the valve 9140 is pushed towards and covers more of the vent holes 9126. In
contrast, as mask pressure decreases, less re is d to the valve 9140, thus
the valve 9140 moves away from and covers less of the vent holes 9126.
Reducing the vent noise for the nt flow vent design may be
accomplished by altering the vent flow characteristics by the use of a flow regulating
valve or membrane 9140. However, the membrane 9140 may increase vent noise over
traditional moulded or static vents, i.e., the vent holes do not change form or shape
during changes in pressure. This noise may be uted to a number of factors,
including: 1) the change of the velocity of flow through the regulated vents as the vent
holes 9126 are opened or closed by the membrane 9140 and/or 2) flow disturbances
caused by the membrane 9140 that generate noise, i.e., turbulence. For example,
changing the direction of vent flow can cause turbulence, which may then result in
noise from a number of factors. This can be caused by gases colliding into the
es of the vent (vent walls or CFV membrane) 9140, or air passing over the
surface of the vent (vent walls and/or membrane) 9140. Thus, partially closing vent
holes 9126 can generate more noise due to factors 1) and/or 2) above.
As mentioned above, an aspect of the present technology includes a vent
with a substantially constant flow within a therapeutic pressure range (i.e., 4-20 cm
H2O, or 2-40 cm H2O). To meet the desired vent flow curve under pressure changes,
the vent holes’ 9126 flow curve may be varied dynamically over the therapeutic
pressure range. This may be accomplished by ng the size, number, and/or shape
of the vent holes. Varying such characteristics may lead to changes in flow
characteristics of gases passing through the vent holes, which can lead to an increase
in vent noise. Using moulded vent technology that includes a converging vent hole
shape as gases exit the vent into the atmosphere, i.e., converging from the al
vent holes 9126 to the external vent holes 9125, noise of the vent flow may be tuned
to a m. r, it should be understood that moulded vent holes do not
change size, shape, or number under pressure changes. Accordingly, deformable
membranes or flaps 9140 that move under pressure to close off or open vents may be
used to vary the flow through the vent holes 9126. Deformable membranes or flaps
9140, however, may generate undesirable noise levels due to the change of the
velocity of flow through the regulated vents as the vent holes 9126 are opened or
closed by the membrane 9140 and/or by having lly closed vent holes 9126.
It may be le to reduce such noise by including membrane flaps 9140
that progressively close off vent holes 9126 as pressure increases, wherein the flap(s)
9140 is fixed on one end such that the flap 9140 deflects under pressure changes. A
m with this technology is that the membrane 9140 may only partially close off a
given vent hole 9126, which can lead to flow passing between the vent hole 9126 and
membrane 9140 at high velocities. This, in turn, generates noise as air passes along
the surface of the vent holes 9126 and membrane 9140 or collides into these surfaces.
It is possible to me this issue by reducing the number of regulated
vent holes, while maintaining an l substantially constant vent flow within the
therapeutic pressure range to reduce vent noise. A desired noise levels can be
maintained using moulded vent holes (i.e., static vents). These vent holes, however,
may not be able achieve the desired flow curve (i.e., a substantially constant flow rate
over a therapeutic pressure range between 4-20cm H20). This may be achieved by
combining some regulated vent holes with static vent holes, such that the overall vent
flow is substantially constant over a therapeutic pressure range. Increasing the number
of static vents, which are not regulated by a membrane, may result in a reduction in
overall vent noise.
This introduction of moulded vent holes, however, may introduce a new
problem, whereby it may be difficult to ensure a substantially constant vent flow
within the therapeutic pressure range using a combination of static vents and regulated
vents. It is known, as shown in Fig. 16, that the vent flow characteristics of moulded
static vent holes is a logarithmic curve where vent flow ses as pressure
increases. To compensate for the flow of the static vents, the regulated vents should
provide an inverse flow curve where vent flow decreases as pressure increases. Thus,
the membrane 9140 regulating the vent holes 9126 may be tuned to provide such a
vent flow.
There are a number of ways to tune the membrane 9140 to e a vent
flow that is inverse to the logarithmic flow curve of the static, moulded vents. For
example, the shape/structure of the membrane 9140 may be changed to tune the flow
curve of the regulated vents and the al of the ne 9140 may be changed
to tune the flow curve of the regulated vents.
An annular disc membrane 9140 structure of the CFV membrane, as
shown in Fig. 20, may allow the membrane 9140 to be tuned in a number of ways
such that it changes the regulated vent flow. The regulated vent flow may be altered
by how much of the vent holes 9126 are d/opened under a fixed pressure. A
membrane 9140 that covers more of the vents under a fixed pressure would have a
lower vent flow than one that covers less. The annular disc structure 9140 may allow
for the membrane 9140 to be readily tuned to cover varying amounts of the vents
under a fixed re. One way this may be done is by changing the er of the
central orifice or by changing the width of the vent engaging surface.
The overall size of the ne 9140 is restricted by the size of the CFV
unit housing 9120, however, it is desirable to reduce the size of the CFV as much as
le. Thus, the width of the vent hole engaging surface may be adjusted by
ing the size of the central orifice. An increase in the size of the central orifice
results in the width of the vent hole engaging surface to also be d. This
reduction in width, in turn, results in a reduction in surface area of the membrane
9140. The reduction in surface area means there is less resistance to deformation
under a fixed pressure, whereby more of the vent holes are covered at the fixed
pressure compared to a wider ne 9140 (i.e., more surface area). This principle
holds true within a predetermined range of surface area. That is, if the surface area is
too low such that there is not enough surface (i.e., width of the vent hole engaging
surface is too low), then more force is required to deform the membrane 9140 (i.e., it
bottoms out).
The membrane 9140 thickness may also be varied such that it deforms
more readily under a fixed pressure. For example, a thinner ne 9140 would
more readily deform under a mask pressure of 15 cm H2O when compared to a
r membrane 9140 of the same shape at the same pressure.
The membrane 9140 may also be structured such that it freely moves to
cover the vent holes 9126 under a fixed pressure. For example, in related
technologies, the membrane 9140 may be fixed at a point, e.g., on the vent housing
9120 such that it is hinged relative to the fixed point and the membrane 9140 would
be deflected about the fixed point due to pressure changes.
The design of the CFV membrane 9140 according to an example of the
present technology allows it to freely move between a retaining structure and a vent
hole surface. This configuration may allow the membrane 9140 to be more easily
tuned to adjust the vent flow when compared to a flap design, i.e., where the
membrane is fixed on one end and moves ve to the fixed end.
A membrane 9140 that is more flexible/compliant may deform more
readily under a fixed pressure/load, thereby covering more of the vent holes 9126 in
comparison to a stiffer membrane. Thus, changing the material of a membrane 9140,
while otherwise having the same size and structure, to a more flexible material will
allow the ne 9140 to deform more readily under the same pressure to cover
more of the vent holes 9126 and reduce vent flow. Thus, this may allow tuning the
membrane 9140 to e the desired vent flow curve within the therapeutic pressure
range.
A number of ways, as mentioned above, can be used to provide a
membrane 9140 that responds to re within the targeted eutic range to
provide a predetermined vent flow curve, i.e., an l substantially constant vent
flow rate between the pressures of 4-30 cm of H2O. It also may be desired to provide
such a constant vent flow while minimizing vent noise, one on may be to
maximize the number of static non-membrane regulated vents and have the minimum
number of membrane regulated vents that provide an average total vent flow that is
substantially constant. This flow curve is shown by the thicker, solid line entitled
“Passive vent only” in Fig. 19. In this example, the dashed line represents the static,
non-membrane regulated vents, while the thinner, solid line entitled “Combination of
the CFV & passive vents” represents the combined vent flow. It is e that the
vent flow of the static vents progressively increases as pressure increases, while the
CFV membrane regulated vents progressively decreases to a threshold.
Another cause of noise may be attributed to vent flow disturbances caused
by the CFV ne 9140 that may also impact the flow of air flowing through the
static vents. In a related technology, the static vents were positioned proximal to the
CFV membrane regulated vents, i.e., the vent holes were positioned on the same
surface of the CFV housing 9120. This led to noise being generated even for the nonregulated
static vents as the ne had impact on the flow characteristics of the
static vent flow. Thus, it may be desirable to position the static vents away from the
CFV membrane regulated vents such that the membrane 9140 does not impact the
static vent flow therethrough. In an example of the t technology, the static vent
holes are positioned on a distal surface from the CFV ted vent holes. For
example, the static vent holes may be positioned on a different component than the
CFV housing 9120. The oning of the static vents may be restricted in that they
may not be able to wash out CO2 as well. The ability to washout CO2 increases as the
static vent holes are positioned closer to the patient. However, the static vent holes
may also be positioned on an opposing side of the HMX relative to the patient to
prevent loss of moisture during exhalation, as explained below.
.4.1.1 Vent g
FIGS. 42A to 42G depict examples of a vent system 13400 according to
an example of the present technology. The vent system 13400 includes a vent
housing 13401 that may include an outer wall 13402 and the outer wall 13402 may
define the outer ery of the vent housing 13401. The vent housing 13401 may
also include an inner wall 13410 that may define an inlet for the flow of gas generated
by the RPT device 4000 and directed into the plenum chamber 3200 and toward the
patient for therapy. As can be seen, the outer wall 13402 and the inner wall 13410 are
formed as tric circles in this example.
Positioned between the outer wall 13402 and the inner wall 13410 is a
base. The base may further comprise an outer base 13403 and an inner base 13406.
The outer base 13403 may extend from the inner periphery of the outer wall 13402
and the inner base 13406 may extend from the outer periphery of the inner wall
13410. As can be seen, the outer base 13403 and the inner base 13406 are also formed
as concentric circles in this example.
The outer base 13403 may include one or more outer orifices 13404
distributed ly around the outer base 13403. These outer orifices 13404 may
extend entirely h the outer base 13403 to provide a flow path from the interior
of the vent system 13400 to atmosphere. The outer orifices 13404 may be straight,
i.e., dicular to the outer base 13403, or the outer orifices 13404 may pass
through the outer base 13403 with a curved path or a slanted path. The diameter of the
outer orifices 13404 may be constant along their length or the diameter may be varied.
The outer orifices 13404 may all be identical or some may be different from others.
The edges of the outer orifices 13404 may have a chamfer or a fillet. The outer base
13403 may at least partially support the membrane 13430 to prevent the membrane
13430 from completely occluding the inner orifices 13407. ingly, the outer
base 13403 may extend higher up than the inner base 13406, as can be seen in FIGS.
42A to 42G.
The vent housing 13401 may also include lateral membrane supports
13405 distributed about the outer base 13403 and the inner periphery of the outer wall
13402. The lateral membrane supports 13405 may abut and prevent the membrane
13430 from moving laterally during use, thereby covering the outer orifices 13404. As
will be explained below, it may be desirable not to obstruct the outer orifices 13404 so
that the vent system 13400 will be able to maintain a substantially constant vent flow
rate over a large proportion of the range of l therapeutic pressures. Therefore,
the lateral membrane support 13405 may protrude radially inward beyond the edges
of the outer orifices 13404. The lateral membrane supports 13405 may be semicircular
, as in FIGS. 42A to 42G. In the es depicted in FIGS. 42A to 42G, the
outer orifices 13404 are distributed evenly in groups of three between adjacent lateral
membrane supports 13405 about the circumference of the outer base 13403.
The vent housing 13401 may also have a circular shape. However, the
vent housing 13401 may also be shaped ically or the vent housing 13401 may
have a nal shape, such as a triangle, a square, a rectangle, a pentagon, a
hexagon, etc. In any of these configurations, the membrane 13430 may be shaped to
pond with the shape of the vent g 13401.
The inner base 13406 may be positioned radially inward of the outer base
13403 and the inner base 13406 and the outer base 13403 may be joined by base
connectors 13408 distributed ly therebetween. Between nt base
connectors 13408 and between the inner base 13406 and the outer base 13403 there
are one or more inner orifices 13407. The inner orifices 13407 in these examples are
shaped as slots with an arc-shaped cross-section. However, it is envisioned that the
inner orifices 13407 may be circular holes, similar to the outer orifices 13404. The
inner orifices 13407 extend completely through the vent housing 13401 between the
inner base 13406 and the outer base 13403. As will be explained below, it may be
desirable to allow the inner orifices 3407 to be at least lly obstructed by the
membrane 13430 to allow the vent system 13400 to in a substantially constant
vent flow rate over a large proportion of the range of typical therapeutic pressures.
The edges of the inner orifices 13407 may have a chamfer or a fillet.
The inner base 13406 of the vent housing 13401 may also include several
ne spacers 13409. The membrane spacers 13409 may be evenly distributed
radially about the inner base 13406. As shown in FIGS. 42A to 42G, the membrane
spacers 13409 may be located on the edge of the inner base 13406 so as to fade into
the inner wall 13410. The membrane spacers 13409 are provided to at least partially
support the membrane 13430, as will be described in greater detail below. The
membrane s 13409 may extend from the inner base 13406 in a semi-cylindrical
shape or in a gular shape, as in FIGS. 42A to 42G. The edges of the membrane
spacers 13409 may have a chamfer or a fillet.
The vent housing 13401 may also include one or more recesses 13415
spaced around the opposite side of the outer base, as can be seen in FIGS. 42A to
42G. The recesses 13415 may be separated by recess dividers 13414. The outer
orifices 13404 may extend through the outer base 13403 and open into the
ponding recesses 13415 and multiple outer orifices 13404 may open into a
single recess 13415.
In an alternative example, the vent housing 13401 may only include one
group of orifices that are analogous to the inner orifices 13407 described above in that
the vent flow passing therethrough can be restricted by the membrane’s 13430
position. Accordingly, there may also be another group of orifices provided elsewhere
on the patient interface 3000 that are analogous to the outer orifices 13404 described
above in that the vent flow passing therethrough is not restricted by the membrane
13430, regardless of the membrane’s 13430 position. The latter group of orifices that
are not restricted by the membrane 13430 may be placed on any of the plenum
chamber 3200, the seal-forming structure 3100, the decoupling structure 3500, the
vent connector tube 4180, or other component that is closer to the patient than the
vent housing 13401. It is envisioned that the principles of operation of the vent
systems 13400 described above will apply to such an alternative arrangement, but the
ability to locate the orifices that are not restricted by the ne 13430 closer to
the patient may improve the discharge of exhaled CO2.
The vent housing 13401 may be made from a single, homogeneous piece
of al. The material of the vent housing 13401 may be relatively rigid. The
material of the vent housing 13401 may be polycarbonate.
.4.1.2 Membrane
FIGS. 43A to 43G also depict views of an exemplary membrane 13430
with the vent system 13400 and positioned nt to the vent housing 13401. The
ary ne 13430 may be used with any of the various vent housing 13401
urations sed above. The membrane 13430 may be in the shape of a flat,
circular disk. In other words, the thickness of the membrane 13430 (see FIGS. 43F
and 43G) may be small relative to its outer er. The thickness of the membrane
13430 may be uniform throughout, as shown in FIGS. 43F and 43G. Alternatively,
the thickness of the membrane 13430 may be variable in a radial direction.
The membrane 13430 includes a ne opening 13431 such that
when assembled onto the vent housing 13401, the flow of air through the inlet 13411
also passes through the membrane opening 13431 and along to the patient. The
membrane 13430 also includes a patient-side surface 13432 that faces towards the
patient in use and an atmosphere-side e 13433 opposite the patient-side surface
13432 that faces s the atmosphere in use. Additionally, the atmosphere-side
surface 13433 faces towards the vent g 13401 when assembled. The ne
13430 also includes an inner surface 13434 that defines the membrane g 13431
and an outer surface 13435 that is opposite the inner surface 13434.
The inner radius, i.e., the radius of the inner surface 13434, and the outer
radius, i.e., the radius of the outer surface 13435, may be selected such that the
membrane 13430 can be located over the inner orifices 13407 in use without covering
the outer orifices 13404. Also, the inner radius and the outer radius may be selected
such that the membrane 13430 covers a ntial portion of the inner base 13406
while being supported on the membrane spacers 13409 proximal to the inner surface
13434 and on the outer base 13403.
The membrane 13430 may be made from a single piece of homogeneous
material. The material maybe elastically deformable such that the membrane 13430
can be deflected in use by the pressure from the flow of air. The material may be
silicone. The ne 13430 may be “tuned” to deform in a desired manner by
ng one or more of its thickness, length, material, shape, inner radius, and/or outer
radius.
.4.1.3 Constant Flow Rate Vent system
FIGS. 43A to 43G depict several views of exemplary vent systems 13400
with the membrane 13430 assembled with the vent housing 13401. In FIGS. 43A to
43G, the inner wall 13410 does not extend above the inner base 13406. In the
examples where the inner wall 13410 extends upward from the inner base 13406, the
inner wall 13410 may provide a baffle function that separates the flow of gas traveling
into the vent system 13400 via the inlet 13411 from the vent flow exiting the vent
system 13400, which in turn may reduce the amount of flow traveling in from the
inlet 13411 and then directly out of the vent system 13400.
In the examples of FIGS. 43A to 43G, a portion of the membrane 13430
proximal to the outer e 13435 can be seen supported on an inner portion of the
outer base 13403. Also, a portion of the membrane 13430 proximal to the inner
surface 3434 can be seen supported just above the membrane spacers 13409.
However, the membrane 13430 may deform towards the ne spacers 13409 by
virtue of its own weight such that the membrane 13430 is also supported on the
membrane spacers 13409 even though there may not be any air pressure g the
deformation.
FIGS. 43A to 43G also show the membrane’s 13430 location constrained
by the lateral membrane ts 13405. As explained above, the membrane 13430
may be shaped and dimensioned to cover only the inner orifices 13407 and not the
outer es 13404. However, the membrane 13430 may not be directly attached to
the vent housing 13401 and, as such, may be free to move. Therefore, a ient
number of lateral membrane supports 13405 can prevent lateral movement of the
membrane 13430 so that the membrane 13430 cannot cover one or more of outer
es 13404 in use.
The inverse of these examples is also envisioned in which the outer
orifices 13404 may be covered by the membrane 13430 and the inner orifices 13407
are not blocked by the membrane 13430. Accordingly, lateral membrane supports
13405 may be provided to prevent the membrane 13430 from covering the inner
orifices 13407.
As explained above, the exemplary vent s 13400 may include a
membrane 13430 oned over the inner orifices 13407 to at least partially restrict
the flow of gas through the inner orifices 13407, while the vent flow through the outer
orifices 13404 is not restricted by the membrane 13430.
It should also be understood that the features of the vent system 13400
bed in sections 5.4.1.1 to 5.4.1.3 may be incorporated into any of the vent
adaptors 9100 disclosed in section 5.4.5.
.4.2 Vent Diffuser
The vent adaptor 9100 may also comprise a portion for housing a diffuser
9146. The diffuser 9146 may be removable for replacement. The diffuser 9146 may
have an annular disc shape that ments the shape of the annular surface of the
vent housing 9120 on the side facing the atmosphere, i.e., external to the inlet flow.
The diffuser 9146 may cover the vent holes 9125 and may diffuse the vent flow after
it exits the plurality of vent holes 9125. That is, the vent flow flowing through
moulded vent holes 9125 may flow through the diffuser 9146 prior to reaching the
atmosphere.
The diffuser 9146 may also act as a sound absorbent al to reduce
some of the noise ted by the CFV membrane 9140 regulated and static vents.
Fig. 26 illustrates a cross-section through some of the es 3402. The
orifices 3402 are illustrated as holes through a wall 3404 of the plenum chamber
3200. However, the orifices 3402 may be located in locations other than the wall
3404. For example, the orifices 3402 may be located between the decoupling
structure 3500 and the connection port 3600 or in a portion of the air circuit 4170,
preferably near the connection port 3600 or in the vent adaptor 9100. The holes are
illustrated with a diameter that is r than an axial length of the hole. The length
and/or diameter may be chosen so that an appropriate flow rate is generated when the
plenum r 3200 is pressurized to the y pressure. The flow through the
orifices 3402 may be choked (e.g. a Mach number of 1) at the therapy pressure (e.g. at
4 cmH2O or greater pressure) or the flow may generate less than sufficient pressure
drop to be choked. A choked flow may result in substantially all of the re drop
in the vent 3400 being caused by the orifices 3402. The arrows conceptually illustrate
direction of flow when the plenum chamber 3200 is pressurized above ambient
pressure.
The orifices 3402 are formed through a thickness of material of the wall
3404. Each of the orifices 3402 defines an axis, e.g., along a center of the orifice.
The axis forms an acute angle with a normal to a e of the wall 3404. The angle
may be between 15 and 75 degrees or between 30 and 60 degrees, including any
integer within the stated ranges. For example, the angle may be about 45 degrees.
The orifices 3402 are covered by a ing member 3406 so that flow
exiting the orifices 3402 impinges on and flows at least partially into the diffusing
member 3406. The diffusing member 3406 may be formed from a material, such as a
porous material, that allows gas to flow through the material but diffuses any jet or
other flow formation exiting the es 3402. Some suitable examples of diffusing
material include a non-woven fibrous material; a woven fibrous material; or an open
cell foam material. The diffusing material may be similar to or the same as a filter
media. The diffusing member 3406 may reduce perceptible noise generated by the
vent 3400 in use (e.g., when therapy pressure is applied).
The diffusing member 3406 is rated as covered by a blocking
member 3408 that prevents gas from flowing out of the orifices 3402 and directly
through the diffusing member 3406. The blocking member 3408 may be constructed,
at least in part, from an air-impermeable material. The air-impermeable material may
be any suitable flexible or rigid al. For example, the air-impermeable material
may be a rigid plastic (e.g., molded polycarbonate) or a flexible plastic (e.g., a plastic
commercially available in sheet form). The blocking member 3408 may be formed
integrally with the ing member 3406, formed separately but permanently affixed
to the diffusing member 3406, formed separately and in removable t with the
diffusing member 3406, or combinations thereof. The blocking member 3408 is
illustrated as te the outlet orifices 3402 with respect to a thickness of the
diffusing member 3406.
The blocking member may cause the flow to change ion (with
respect to the direction through the es 3402) before exiting the diffusing member
3406. The blocking member 3408 and/or diffusing member 3406 may be configured
so that flow out of the orifices 3402 must flow at least a predetermined ce
through the diffusing member 3406 prior to exiting to ambient atmosphere. The
blocking member 3408 may also be configured to provide a particular direction and/or
orientation for flow exiting the vent 3400 to minimize any disturbance to the wearer
and/or bed partner caused by the flow. For example, the blocking member 3408 may
cause gas to flow through the diffusing member 3406 and generally parallel to a
surface of blocking member 3408 t to the diffusing member 3406.
In Fig. 26, the orifices 3402 and the diffusing member 3406 are oriented
relative to one another such that a central axis of each of the es is not
perpendicular to a nearest surface of the diffusing member 3406, although a
perpendicular arrangement could also be provided as illustrated in Fig. 8.
Channels 3410 may also be provided on an outer surface of the wall 3404.
The channels 3410 are illustrated with a V-shaped cross-section but could be formed
with any suitable cross-section such as a U-shape. The channels 3410 may be
configured to allow liquid to drain away from one or more outlets of the orifices 3402.
The orifices 3402 may be formed in a leg of the V-shape or U-shape.
Fig. 27 illustrates an alternate configuration of the ng member 3408.
In Fig. 27, the blocking member 3408 includes holes 3412. The holes 3412 may
direct the flow out of the diffusing member 3406 on the opposite side from the
orifices 3402 but in a different direction. Thus the flow path is not straight h
the orifices 3402 and the diffusing member 3406. Although the arrows associated
with the holes 3412 are illustrated parallel, this is for ease of illustration only. The
holes 3412 may be configured to redirect the flow in multiple directions.
The holes 3412 each define an axis that is neither aligned with nor parallel
to an axis defined by each of the es 3402. When viewed in the cross-section of
Fig. 27, any one axis defined by a hole 3412 and any one axis defined by an orifice
3402 forms an angle. The angle may be between 15 and 75 degrees or between 30
and 60 degrees, ing any integer within the stated ranges. For e, the
angle may be about 45 degrees.
Figs. 28-30 illustrates an alternate configuration of the vent 3400. Fig. 28
illustrates a partially exploded view, Fig. 29 illustrates a fied assembled view
and Fig. 30 illustrates a sectional view taken along line 30-30 of Fig. 29. In
these figures, the orifices 3402 are illustrated in a circular array around a central hole
3414. The ar array is illustrated to include three circular rows of holes where
the two inner-most circular rows are closer together than the outer-most ar row,
but any number of circular rows may be provided an spacing between the rows may
be equal. The central hole 3414 allows for fluid communication between the plenum
chamber 3200 and the connection port 3600 and thus the air circuit 4170. The
ing member 3406 and the blocking member 3408 are also illustrated as being
disposed around the central hole 3414. With this configuration, the blocking member
3408 may be removably attached (e.g., a removable snap fit or ed engagement)
or y attached (e.g., permanent adhesive or a snap fit that must be broken to
disassemble) and the diffusing member 3406 may be fixed to the blocking member
3408 or not fixed to but retained by the blocking member 3408. As best viewed in
Fig. 29, radial openings 3416 are provided for gas to escape the ing member
3406 radially outward from the central hole 3414.
Figs. 31A to 31C illustrate another alternate configuration of the vent
3400. Fig. 31A illustrates a l view of a flow passage in the form of an elbow
3418, which may be disposed between a decoupling structure 3500 and connection
port 3600, and includes a vent 3400. This configuration largely conceals the features
of the vent 3400 and thus the remaining description is with respect to Figs. 31B and
Fig. 31B illustrates an axial view with the cap 3422 and diffusing member
3406 omitted. This provides a clear view of the outlet orifices 3402. Two annular
rows, each ing forty of the outlet orifices 3402 are illustrated. The orifices are
offset so that the outlet orifices 3402 in the inner row and the outer row are not
radially aligned. This configuration may allow for annular rows to have closer radial
spacing. Although two rows are illustrated, any number of rows may be provided, for
example one row or three or more rows. Although forty outlet orifices 3402 are
illustrated in each annular row, more or less may be provided as required to maintain
riate levels of gas washout. For example, one, five, ten, fifteen, , twenty
five, thirty, thirty five, forty, forty five, fifty or more outlet orifices 3402, or any
number in between, may be provided per annular row.
In Fig. 31C, the annular array of es 3402 are visible in the crosssection
h a wall 3420. The wall 3420 is similar to wall 3404 except that the
wall 3420 is illustrated remote from the plenum chamber 3200; however, the wall
3420 may be part of the plenum chamber 3200.
The diffusing member 3406 is illustrated as a ring-shape with a
rectangular cross-section. The blocking member 3408 is illustrated as a relatively
thin, like ring on a side of the diffusing member 3406 opposite the orifices
3402. The blocking member 3408 may be affixed to the diffusing member 3406 by
any le means, for example by adhesive.
A cap 3422 is illustrated covering the diffusing member 3406 and the
blocking member 3408. The cap 3422 may be in contact with the blocking member
3408 such that the diffusing member 3406 is compressed against the wall 3420.
Alternatively, the diffusing member 3406 may not be compressed against the wall
3420. The cap 3422 may serve as the blocking member 3408, in which case the ring -
shaped ng member 3408 illustrated in Fig. 31C may be omitted.
The cap 3422 may include an angled, annular flange 3424 that may be
spaced away from the wall 3420 to form an annular gap 3426. The annular flange
3424 may also be considered skirt-like or frusto-connical. The annular gap 3426 may
e a flow path to ambient atmosphere such that the flow of gas washout is not
overly cted. Alternatively, one or more openings (such as radial opening 3416)
may be provided in the annular flange 3424 to provide a flow path to ambient
atmosphere, which may also allow for elimination, in whole or in part, of the annular
gap 3426.
The cap 3422 is illustrated with an r groove 3428 mated with an
annular protrusion 3430 to hold the cap 3422 in place. The r protrusion may be
continuous to form a snap fit or may be multiple, annularly spaced annular protrusions
to e a configuration that allows for minimal or no interference upon axial
ion followed by a twist to provide axial interference and hold the cap 3422 in
place. In Fig. 31C, the annular protrusion 3430 is illustrated as three annularly spaced
annular protrusions. A lip 3432 of the annular groove 3428 may be omitted in three
corresponding locations and sizes to provide for d or no interference of the cap
3422 during the axial insertion. Other forms of attachment are le. For
example, a threaded fastening arrangement may be provided, the cap 3422 may be
held in place with adhesive or welding. Releasable fastening such as the illustrated
configuration or a threaded connection may allow for the diffusing member 3406 to
be replaced if, for example, the diffusing member becomes damaged, clogged or dirty.
Although the vent 3400 is illustrated on one side of the bend (e.g.,
upstream with respect to an exhalation direction) in the elbow 3418, the vent 3400
may be am or downstream of the bend.
Figs. 32A to 32C rate another alternate configuration of the vent
3400. Like reference numbers are r to those described above and thus further
description is omitted except as noted below. The vent 3400 in these figures is
formed around an example of the decoupling structure 3500 that includes a ball 3434
and socket 3436 that are part of an elbow 3418. In the form illustrated here, the ball
3434 and socket 3436 allow three degrees of rotational freedom. However, fewer
degrees of rotational freedom are possible, e.g., one or two degrees of rotational
freedom.
As best viewed in Fig. 32D, the cap 3422 is connected by way of a snap
fit connection 3438 with a first half 3440 located on the cap 3422 and a second half
3442 on the mating component. Six each of the first half 3440 and second half 3442
are provided between six of the radial openings 3416, three of which are visible in
Fig. 32A. However, more or less may be ed as necessary to provide adequate
retention and/or flow rate.
As best seen in Fig. 32C, forty-four orifices 3402 are illustrated equally
spaced in a single annular row. However, the number and spacing of the orifices
3402 may take other configurations. For example, fewer orifices 3402 may be
provided if, for example, lower flow rate is required or more orifices 3402 may be
provided if, for example, greater flow rate is required. And as explained above, more
rows may be provided. Also, the es need not be in an annular array. If, for
example, the orifices are located other than in the illustrated location, the orifices may
be arranged in a grid based on Cartesian coordinates. atively, the orifices 3402
need not be in any type of row and may be d in random or pseudo random
locations.
.4.3 Heat and Moisture Exchanger (HME)
Heat and moisture exchangers (HMEs) may comprise materials that have
water retaining properties. atory pressure therapy (RPT) can result in drying of
the s causing breathing fort in patients. To prevent this, a humidifier
may be used in conjunction with a respiratory pressure device to deliver humidified
air to the patient. This added humidifier may increases the size and power
requirements of RPT s.
It is known that patient’s generate a level of humidified air upon
exhalation, which comes from the mucosa of the airways. HMEs can be used to
recycle this exhaled moisture by capturing humidity from humidified air upon
exhalation then redelivering this to the patient. One nge in the use of HMEs is
their efficacy (i.e., being able to capture enough heat and moisture) and their impact
on therapy (i.e., the HME may be placed in the flow circuit and therefore cause flow
impedance).
To improve efficacy, an aspect is to reduce any losses of heat and
moisture that is captured by the HME. A problem with the use of HMEs in RPT may
be that heat and moisture expired by the patient is lost through venting prior to
reaching the HME. In order to minimize such losses, the HME may be placed
proximal to the patient’s s (i.e., the source of humidity) and place the vent on
an opposing side of the HME, i.e., away from the patient. This uration may
ensure that expired humidified gases flow through the HME such that moisture is
captured by the HME prior to exiting through the vent. The vent adaptor may be
configured such that the HME is positioned between the patient’s airways and the
constant flow vent.
In es, where an HME is ed in the vent adaptor, the RPT
system may not include a humidifier. The humidification of ng pressurized,
breathable gas may be sufficiently accomplished by the HME such that a humidifier
(e.g., powered humidification using an arrangement such as that depicted in Figs. 5A
and 5B) may be unnecessary and can be excluded. Alternatively, if a humidifier is
included in the RPT system when an HME is provided, the fier may be
deactivated or simply not powered on. In yet another alternative, the HME and the
RPT humidifier may act in concert with one another to provide the desired total
humidity, e.g., with the HME providing a portion of the desired humidity and the RPT
humidifier ing a second portion of the desired humidity.
The vent adaptor may also comprises an HME unit that is removable.
That is, the vent adaptor can be used with or without the HME. The HME unit may
comprises a housing that holds the HME is place. The g can be opened (the
housing may comprises a front and rear component) to remove the HME.
The HME may be ed to maximize surface area per unit volume for
heat and moisture ge. In addition, the HME may also be designed to decrease
its impact on flow impedance. The design may ses a plurality of corrugations
to allow flow to pass through said corrugations. The HME may be formed as a coiled
layer of HME material comprising the corrugations.
As described above, the CFV may reduce flow wastage by regulating vent
flow to a level that is above but close to the minimum required vent flow rate. As flow
e is reduced, the level of humidity loss in the therapy system may also be
reduced. It is known in the art that ts expire humidified air, which may in turn
cause drying of the mucosa. Applying RPT treatment for SDB may exacerbate this
drying. Thus, reducing the amount of flow required to achieve therapeutic pressure
and concurrently reducing the level of humidified air loss from the system may result
in a reduction of mucosal drying.
One way to increase the level of humidified air delivered to the patient is
by the use of a powered humidification. Another way to humidify the air red to
the patient is by the use of heat and moisture exchangers (HME), which capture the
water vapours in air such that they may be delivered back to the patient. An HME can
be utilized to capture the humidity from patient expiration, which in turn can redeliver
this humidity back to the patient. The HME should be positioned that it captures
enough humidity from d gas flow, as shown in Fig. 17, but allows this humidity
to be redelivered through therapy flow. To ensure that captured humidity from
expired gas flow is maximized, the HME should be placed between the patient and
the vent. If the vent were to be placed between the patient and the HME, it would lead
to the humidity in the expired gas flow being vented prior to reaching the HME for
capture and redelivery. r, the uration shown in Fig. 17 can also result in
humidity being lost through venting via therapy flow going through the HME then
directly out the vent (prior to patient delivery). This flow has been labelled “HME
vent flow” in Fig. 17. The HME vent flow becomes more of an issue when the flow
rate of the therapy increases. As shown in the graph in Fig. 18, the flow rate may
se as mask pressure increases. This flow may be increased to compensate for
vent flow losses. When the flow rate increases, the velocity of the therapy flow
increases, which may cause the therapy flow to penetrate the HME deeper. Some of
this ating flow is delivered to the patient, however, a portion of this flow may
also be directed to the vent prior to patient delivery (as shown by the HME vent flow).
Therefore, the HME vent flow may also result in humidity losses by drying the HME.
As shown in the graph in Fig. 18, the CFV may reduce the vent flow rate
over the same pressure range as compared to the standard FFM nom flow vent. This
reduction in flow may reduce the HME vent flow, thereby reducing humidity losses.
In other words, less flow occurs at the same pressures in the CFV system when
compared to the standard vent system, uently reducing the HME vent flow.
This reduction in HME vent flow enhances the capability of the HME to capture and
redeliver humidity from the expired gas flow thereby synergistically enhancing the
HME effect to reduce mucosal drying.
Another way of reducing the HME vent flow may be to redirect the flow
direction such that less flow passes through the vent and is redirected back into the
. The redirection can be achieved by structures, e.g., baffles, positioned in the
flow path n the HME and the vent such that less flow is directed out the vent
into the atmosphere.
The t technology is capable of achieving near powered
humidification levels without the use of d humidification. Since powered
humidification is no longer required, the flow generator may be simplified further,
e it no longer requires a water reservoir and heating mechanism to deliver
powered humidification to therapy flow. ore, both the CFV and the HME may
allow a flow generator associated with the present technology to be effective in
providing RPT treatment for OSA and other SDB, without the need to complex
pressure/flow control and powered humidification, which may tely benefit the
patient by providing a substantially smaller flow tor with less controls.
Figs. 25A to 25D show examples of a HME according to the present
technology. Fig. 25A shows a cross section of a HME 7000 comprising a corrugated
structure 7002 comprising a plurality of corrugations 7030 between a substantially
planar substrate top structure 7010 and a substantially planar substrate base structure
7020 to form a concertina layer 7001. The layer 7001 comprises a plurality of
or channels 7012 formed between a superior surface of the corrugated structure
7002 and the top structure 7010. In addition, the layer 7001 comprises a plurality of
inferior ls 7022 between an inferior surface of the ated structure 7002
and the base structure 7020. The HME 7000 allows for a flow of breathable gas and
expiratory gas to flow through the plurality of superior 7012 and inferior 7022
channels along a surface of the corrugated structure to exchange heat and moisture.
Moisture is ed from the expiratory gas exhaled from a patient and retained in
the material of the corrugated structure 7002. The material of the corrugations 7030,
the top structure 7010, and/or the base structure 7020 may comprise paper or a paper
based material that is able to absorb water and/or heat. The material of the
corrugations 7030, the top structure 7010, and/or the base structure 7020 may be
porous, water-permeable, and/or air-permeable. The retained moisture may
subsequently be redelivered to the patient by humidifying a flow of breathable gas
delivered to the patient’s airways. In other words, the flow of able gas delivered
to the patient’s airways may absorb moisture from the HME 7000. Fig. 25B depicts
the various dimensions of a HME according to these es.
The plurality of corrugations 7030 increase the surface area of the
corrugated structure 7002 that allows for an increase in active surface area for the
exchange of heat and re occurring n the corrugated structure 7002 and
the surrounding volume provided by the plurality of superior 7012 and or 7022
channels. The top ure 7010 and the base structure 7020 may also be formed
from the same heat and moisture exchanging material as the ated structure
7022. Alternatively, the top structure 7010 and/or the base structure 7020 may be
formed of a rigid or semi-rigid al that does not absorb moisture to support the
corrugated structure 7002.
The humidification performance of the HME 7000 is dependent on the
effective surface area of the HME 7000 provided in a fixed volume of space. The
effective surface area is the e area of the HME 7000 that is exposed to the flow
of breathable gas flowing along the surface of the HME where heat and moisture
ge occurs. The surface area per unit volume of the HME 7000 can be adjusted
by providing corrugations 7030 within the heat and moisture exchange portion of the
HME 7000. Furthermore, the surface area per unit volume may also be adjusted by
modifying at least one of the fin thickness, pitch or height of the corrugations or
flutes, which have an impact on the surface area per unit volume of the HME 7000.
The HME 7000 may comprise a plurality of layers 7001 stacked along a
vertical axis of the HME 7000, as shown in Fig. 25C. The layers 7001 may be
vertically stacked such that the base ure 7020 is stacked on top of the corrugated
structure 7002 of an ying adjacent layer 7001. There may be also l layers
7001 of HME stacked in the horizontal direction. Having a number of layers 7001
comprising corrugated structures 7002 that are stacked along a vertical axis of the
HME 7000 further increases the surface area per unit volume of the HME. This
increased surface area within a ined volume allows for increased efficiency in
heat and moisture exchange of the HME 7000. Furthermore, the layers 7001 may be
compressed under a preload, as depicted in Fig. 25D, to increase the number of layers
within a fixed volume to increase the e area per unit volume. The preload is
h
P = 1− final
calculated by the formula: hstart where P is the Preload and hstart is the
corrugation or flute height prior to compression and wherein hfinal is the height of the
corrugation post-compression.
Alternatively, the final three-dimensional shape of the HME 7000 may be
formed by combining layers 7001 of different sizes and shapes to produce a HME
7000 of irregular shape adapted to fit within a plenum chamber 3200 of the patient
interface 3000. The layers 7001 may be laser cut to form the desired shape and size.
As shown in Fig. 25E, displaying an ative example, the HME 7000
may be rolled from a single strip layer 7001 comprising a corrugated structure 7002
extending from the surface of the base structure 7020 to form a plurality of
corrugations 7030. The single strip layer 7001 may be rolled such that the upper
folded portion 7031 of the corrugations 7030 engages the or surface of the base
structure 7020. This uration ensures that the plurality of channels 7012 is
maintained between each roll of the single strip layer 7001.
As mentioned above, the CFV may reduce the vent flow rate over the
same pressure range as compared to the standard FFM nom flow vent. This ion
in flow may reduce the HME vent flow, y reducing humidity losses. In other
words, less flow occurs at the same pressures in the CFV system when compared to
the standard vent system, consequently ng the HME vent flow. This reduction
in HME vent flow may enhance the lity of the HME to capture and redeliver
humidity from the d gas flow, thereby synergistically ing the HME effect
to reduce l drying.
The CFV ne may allow the vent flow to be maintained at or above
the minimum required level within the therapeutic pressure range and may also
regulate the vent flow to below that which would occur with a standard static vent.
Thus, CO2 washout would always remain at sufficient levels. The vent flow may be
tuned such that it allows the minimum level required of CO2 washout. This would
result in the vent flow being minimized, which would in turn minimize the loss of
moisture from the HME.
Another way of reducing the HME vent flow is to redirect the flow
direction such that less flow passes through the vent and is redirected back into the air
delivery circuit. That is, the flow may be redirected such that it zes HME vent
flow, wherein flow penetrates the HME and then flows directly out of the vent. The
redirection of flow can be achieved by structures, e.g., baffles, positioned in the flow
path between the HMX and the vent such that less flow is directed out the vent into
the atmosphere.
Figs. 38A to 38C depict an example of an HME housing 9400 according
to an example of the present technology. The HME housing 9400 may have a twopart
construction that includes a patient-side HME housing portion 9402 and an
atmosphere-side HME housing portion 9404. The patient-side HME housing portion
9402 and the atmosphere-side HME housing portion 9404 may be assembled together
to retain HME al therein. The patient-side HME housing portion 9402 may
include a patient-side HME housing portion cross-bar 9406 to retain the HME
material in an axial direction towards the patient in use and the atmosphere-side HME
housing portion 9404 may include an atmosphere-side HME housing portion ar
9408 to retain the HME material in an axial direction towards the atmosphere in
use. The atmosphere-side HME g portion 9404 may also include one or more
openings 9410 that connect to corresponding tabs 9412 of the patient-side HME
housing portion 9402 to join both ns together. The connection between the
openings 9410 and the tabs 9412 may comprise a snap-fit and may be releasable to
allow the HME housing 9400 to be disassembled so the HME material can be
removed for cleaning or ement.
Figs. 39A to 39C depict another example of an HME housing 9400
according to an example of the present technology. The HME housing 9400 may have
a two-part construction that includes a patient-side HME housing n 9402 and an
atmosphere-side HME housing portion 9404. The t-side HME housing portion
9402 and the atmosphere-side HME housing portion 9404 may be led together
to retain HME material therein. The patient-side HME housing portion 9402 may
include a patient-side HME housing portion cross-bar 9406 to retain the HME
material in an axial direction towards the patient in use and the atmosphere-side HME
housing portion 9404 may e an atmosphere-side HME housing portion crossbar
9408 to retain the HME material in an axial direction towards the atmosphere in
use. The atmosphere-side HME housing portion 9404 may also include one or more
openings 9410 that connect to corresponding tabs 9412 of the patient-side HME
housing portion 9402 to join both ns together. The connection between the
gs 9410 and the tabs 9412 may se a snap-fit and may be releasable to
allow the HME housing 9400 to be embled so the HME material can be
removed for cleaning or replacement. The atmosphere-side HME housing portion
9404 may also include an atmosphere-side HME housing portion ring 9414 and
extending from the atmosphere-side HME housing portion ring 9414 is an HME inner
housing 9416 which may contain the HME material. The HME inner housing 9416
along with the patient-side HME housing n 9402 and the atmosphere-side HME
housing portion 9404 may form an HME bypass passage 9418 to allow a portion of
the flow traveling through the HME housing 9400 to bypass the HME material.
.4.4 Custom Connection
Fig. 6a illustrates a side view of a fluid connector 9000 with a first end
9002 and a second end 9004 mated with one another. A portion of a fluid conduit
9006, which may be part of the air circuit 4170, is connected to the second end 9004.
Instead of the fluid conduit 9006, an adaptor or connector to a fluid conduit may be
provided. An outlet of an RPT device 4000 may comprise a second end 9004 in some
forms of the present technology.
The fluid connector 9000 may be ured to removable form a sealed
connection to allow a flow of air to travel therethrough, such as from the RPT device
4000 to the t interface 3000. The fluid connector 9000 may comprise a plurality
of components, such as a first end 9002 and a second end 9004, which may be
releasably connected to each other to make and/or break the sealed connection.
The first end 9002 and the second end 9004 may form a pneumatic path
therebetween via complementary sealing portions, and be retained to each other by
complementary retaining portions that may be separate portions to the complementary
g portions. Accordingly, each of the first end 9002 and the second end 9004
may comprise a separate sealing portion and a retaining portion, as is described in
further detail elsewhere in the present nt.
Where the sealing function and the retaining function are performed by
te complementary portions, each of the sealing and/or the retaining functions
may be more readily optimised, to s one or more of competing design
requirements. For example, where one pair of complementary portions function to
seal and retain two components, formation of a tight seal may lead to a high frictional
force, decreasing ease of tion and/or disconnection of the components.
Furthermore, where the usability of connection/disconnection is
improved, the seal may not be as robust, such as in cases where the two components
may be subject to forces and/or torques in varying directions and magnitudes. In the
cases of a fluid connector such as those described in the present document, a patient
wearing a patient interface 3000 may move about while asleep, or preparing to go to
sleep, causing the fluid connector to be pulled and/or twisted in various directions.
Thus, one aspect of the t logy relates to a fluid tor
9000, wherein the first end 9002 and the second end 9004 are connected to each other
by complementary sealing portions and complementary ing portions.
In one form, the first end 9002 and the second end 9004 may comprise
complementary sealing ns to form an air seal when connected. The air seal may
be configured to form and maintain a g engagement to allow a flow of air to
travel therethrough. The sealing engagement may be sufficient to allow a pressurised
flow of air to travel therethrough, such as at pressures between 4 cm H2O to 40 cm
H2O to e respiratory therapies.
In some forms, the first end 9002 and the second end 9004 may comprise
complementary portions to retain the first end 9002 and the second end 9004. The
retaining portions may maintain the first end 9002 and the second end 9004 in sealing
engagement with each other, such as by ting accidental disengagement. The
retaining portions may comprise latching mechanisms as will be detailed further in the
present document.
Fig. 6b illustrates a sectional view of the fluid connector 9000 where the
first end 9002 and the second end 9004 are not connected to one another. In this
view, a seal portion 9008 is visible. The seal portion 9008 may be formed from any
material that is suitable for forming a seal in an air path of a device that provides
breathing gas to a patient, for example, silicone. The seal portion 9008 extends
around a first g 9010, which is illustrated as the interior of a first tube 9022. A
latching portion 9012, which may be in in the form of a , is ed in the first
end 9002. The latching portion 9012 may be provided on opposed sides as illustrated
in Fig. 6b, on a single side or all around a periphery of the first end 9002. As
illustrated, the latching portion 9012 is an undercut that is substantially perpendicular
to a central axis of the first end 9002. Other angles are possible depending on the
retention force desired.
The second end 9004 includes a sealing e 9016. The sealing surface
9016 may be formed circumferentially around a second opening 9018 that is
illustrated as the interior of a second tube 9020. The sealing surface 9016 is
illustrated as a substantially annular surface that extends radially and perpendicularly
(i.e., at 90°) away from the second tube 9020. This may result in the sealing surface
9016 being substantially perpendicular to a direction of the fluid flow from the first
end 9002 to the second end 9004. However, the sealing surface 9016 could also
extend outward at an angle such that the sealing e 9016 is beveled. For
example, the sealing surface could be at 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50° or 45°
angle, positive or negative, or any value in n. As can be seen in Fig. 6b, the
second tube 9020 may comprise an overhang portion 9034 that extends beyond the
sealing surface 9016 towards the seal portion 9008. This may result in the overhang
portion 9034 of the second tube 9020 extending through the seal portion 9008 as
illustrated in Fig. 6c. It will be understood that the second tube 9020 need not
comprise an overhang portion in some examples of the present technology.
The overhang n may be configured to align the first end 9002 with
the second end 9004 in one or more ions. The overhang portion 9034 may be
configured to be inserted into a guide portion 9038 on the first end 9002 to act as a
lead-in and align the second end 9004 with the first end 9002 in a radial (or
transverse) direction. Thus the first end 9002 and second end 9004 may have a
male/female relationship. Additionally, a stop 9030 may be provided to limit travel of
the second tube 9020, for example by abutting the overhang portion 9034 at the limit
of travel. Although the overhang portion 9034 is shown as a tube, the ng
portion may not extend continuously around a circumference of the second end 9004,
as it would be internal to the seal created by the complementary sealing portions (seal
portion 9008 and sealing surface 9016). The overhang portion may extend only
partially through the seal portion 9008, such as in castellated extensions, tabs, ribs and
the like.
With the configuration illustrated in Fig. 6c, the interior flow path of the
fluid connector 9000 defined by the first tube 9022, second tube 9020 and stop 9030
may have very little flow restriction because the interior flow path is substantially the
same as the interior of the fluid conduit 9006, for e as evaluated in cross
section shape and size. Thus the fluid connector 9000 may have ible pressure
drop when air is flowing h the fluid connector 9000 throughout a patient’s
breathing cycle and therapy pressure (e.g., at pressures n 4 cm H2O to 40 cm
H2O).
The seal n 9008 may include a portion that ts the g
surface 9016 in any form that is suitable for forming a face seal, such as by tangential
contact therebetween. As illustrated, the seal portion 9008 contacts the sealing
surface 9016 with a substantially frustoconical shape, which is similar to a bellows-
shape or partial s-shape. Alternatively, a partial spherical, or partial toroidal
surface may be provided on the seal n 9008. With any of these shapes, the seal
portion 9008 may t the sealing surface 9016 before the latching portion 9012
and complementary latching portion 9014 are fully or even partially engaged.
atively, the seal portion 9008 and sealing surface 9016 may be separated by a
gap even after the latching portion 9012 and complementary latching portion 9014 are
fully engaged. In this scenario, internal pressurization may cause the seal portion
9008 to move into contact with the sealing surface 9016 and form a seal.
The seal portion 9008 may comprise a resilient and compliant material
such that it may deform under load, while maintaining its original configuration when
the load is removed therefrom. The seal portion 9008 may be configured to be readily
deformed under load to form and/or maintain a seal with the sealing surface 9016. In
some forms, the seal portion 9008 may se a membrane composed of silicone.
The silicone membrane seal portion 9008 may be sufficiently compliant that it would
deform to move into contact with the sealing surface 9016 due to the pressure caused
by the air flow. The ne membrane seal portion 9008 may additionally or
alternatively be sufficiently compliant such that it would maintain a sealing
engagement with the sealing surface 9016 even when compressed from its
undeformed configuration.
The proposed configurations of the seal portion 9008 may provide a seal
that is compliant with respect to a mating ion between the first end 9002 and the
second end 9004 (e.g., rds in Fig. 6b) and/or compliant in a direction radial to
an axis defined by a direction of engagement between the first end 9002 and the
second end 9004 (e.g., up and down in Fig. 6b).
The force necessary to compress the seal portion 9008 (e.g. when
compression is required to form and/or in a seal) may be sufficiently low so as
to not be a significant compressive force. For example, the force ed to
compress the seal n 9008 may be less than a force required to engage the
latching portion 9012 with the complementary latching portion 9014, such as to
overcome any friction in ting the second end 9004 and the first end 9002.
Alternatively, the force required to ss the seal portion 9008 may be less than
half of the force required to engage the latching portion 9012 with the complementary
ng portion 9014. Alternatively, the force required to compress the seal portion
9008 may be less than one tenth of the force required to engage the latching portion
9012 with the complementary latching portion 9014. Thus in a configuration where
the seal n 9008 contacts the sealing surface 9016 before the latching portion
9012 and complementary latching portion 9014 are fully engaged, a user may not
encounter significant force that would be en for full engagement. In some
forms, any force caused by a compression of the seal portion 9008 for connection of
the second end 9004 and the first end 9002 may be sufficiently small that it is
substantially imperceptible to a user. That is, the force perceived by a user in a
configuration n the seal portion 9008 is removed from the first end 9002 may
be substantially cal to a configuration where the seal portion 9008 must be
compressed for connection.
The shapes of the seal portion 9008 according to the present technology
may provide a seal that is compliant opposite to a mating direction between the first
end 9002 and the second end 9004 (e.g., rightwards in Fig. 6b). This may allow for a
seal portion 9008 that can seal with the sealing surface 9016 even if a gap exists
between seal portion 9008 and sealing e 9016 when the fluid connector 9000 is
unpressurized. When pressure is provided to an interior of the fluid connector 9000
(e.g., to the first tube 9022), the seal portion 9008 may expand towards and contact
the sealing e 9016 to form a seal. With this configuration, a user should not
encounter any additional force when connecting the first end 9002 to the second end
9004 beyond the force necessary to engage the latching portion 9012 and
complementary latching portion 9014.
gh specific configurations of the seal portion 9008 are discussed
above, other configurations are possible. For example, some forms of the seal portion
9008 may include an o-ring or a gasket material.
Either the seal portion 9008 or the sealing surface 9016 or both may be
configured such that misalignment between the seal portion 9008 and sealing surface
9016 still results in a seal between the seal portion 9008 and the sealing surface 9016.
For example, the seal portion 9008 and/or the sealing surface 9016 may be configured
to form a seal therebetween while allowing for a range of misalignments in radial (or
erse) and/or axial directions.
For example, the sealing surface 9016 may comprise an annular shape (as
shown in Fig. 6H) configured to form a face seal with a surface of the seal n
9008 in a plurality of radial positions. That is, the seal portion 9008 and the sealing
surface 9016 may form a seal therebetween although an axis of the first tube 9022 and
an axis of the second tube 9020 may be misaligned, for example by 0.5 mm, 1 mm,
1.5 mm, 2 mm, 3 mm or 4 mm. In one form, the sealing surface 9016 may comprise a
sufficiently wide annular portion such that the seal portion 9008 may be able to form
a seal thereto.
The second end 9004 also includes a complementary latching portion
9014. The complementary latching portion 9014 is rated as a cantilevered hook
ing a protrusion that mates or engages with the latching portion 9012. As with
the latching portion 9012, the complementary latching portion 9014 may be provided
on a plurality of (e.g. d) sides as illustrated in Fig. 6b or on a single side. The
complementary latching portion 9014 may be in the form of U-shaped or C-shaped
cut-through as illustrated in Fig. 6d. The complementary ng portion 9014 may
be depressed to engage or disengage the complementary ng portion 9014 from
the latching portion 9012 and allow engagement or disengagement between the first
end 9002 and the second end 9004. Although providing more than two of the
complementary latching portion 9014 is possible, doing so may make it unnecessarily
difficult to disengage the second end 9004 from the first end 9002.
In combination, the stop 9030 and latching portion 9012 may define a
predetermined distance (travel) that the second end 9004 can move with respect to the
first end 9002 while the two ends are ted. For e, if a first axial distance
between the stop 9030 and latching portion 9012 is greater than a second axial
distance between an end of the second tube 9020 and the protrusion on the
complementary latching portion 9014, then the difference n the first axial
distance and the second axial distance will define a predetermined amount of travel
that is non-zero. If the first axial distance and the second axial distance are equal,
then no travel will be possible. However, there may be benefits associated with a
non-zero travel at least with respect to ease of cture because a non-zero travel
will allow for manufacturing tolerance that may reduce cost. Thus it may also be
beneficial for the seal portion 9008 to be configured to form a seal with the sealing
surface 9016 with a worst case manufacturing tolerance and after a predetermined
amount of wear and/or creep in the fluid connector 9000. The shapes for the seal
portion 9008 discussed above may allow for the seal portion 9008 to account for such
a worst case scenario.
As best seen in Fig. 6b, the second end 9004 may include an inner portion
9024 and an outer portion 9026 that are bly coupled to one another at an
interface 9028. The inner portion 9024 may include the seal portion 9008 and the
outer portion 9026 may include the complementary latching portion 9014. As
illustrated, the inner portion 9024 is rigidly or fixedly connected to the fluid conduit
9006 such that the inner portion 9024 and the fluid t 9006 may rotate together
with respect to the outer portion 9026. At least a part of the fluid conduit 9006 may be
overmolded onto the inner portion 9024 to form the rigid connection therebetween. In
other forms, the fluid conduit 9006 may be friction fit, or interference fit into the inner
portion 9024 so as to form a rigid connection.
As best viewed in Fig. 6d, the outer portion 9026 may have an outer
profile that has four sides but also have some features of a circle, which may be
uniquely fiable in comparison to a typical circular profile. The first end 9002
may include a mentarily shaped recess. Thus the first end 9002 includes a
female portion and the second end 9004 includes a male n. Including male and
female portions in the above form, or any other non-standard shape or uration,
may provide ts. First, the fluid connector 9000 sing andard shapes
and/or configurations may not conform to industry standards (e.g., ISO 5356-1),
which include use of a circular spigot including a lead-in taper, onto which a cuff (e.g.
rubber) is inserted over. Although not confirming to an industry standard may seem
counter ive, there may be benefits. For example, the fluid connector 9000 may
be used to connect an RPT device and patient interface that are designed to operate
optimally together. For example, if the RPT device provides a lower flow rate that
can only be taken advantage of by a patient interface that is designed to operate with
that lower flow rate, having a fluid connector 9000 that does not mate with an
industry standard will ensure that only the correct RPT device and patient interface
are used together. Second, particularly with the illustrated profile, the first end and
the second end 9004 may be mated with one another only in a predetermined number
of relative ations (e.g., four). The present four-sided shape also may provide
well-defined sides that are easy to identify and grip for actuation of the
complementary latching portion 9014. Thirdly, a non-standard shape such as that
described herein, or others, may allow a user to readily identify which end of a patient
conduit 4170 may be a complementary connector to another connector, such as an
outlet of the RPT device.
Fig. 6e illustrates another example of a present logy, wherein a port
9032 is included in the first end 9002. The port 9032 may be used to sense pressure
downstream of a blower and outside of a housing of the blower, such as by sensing a
pressure downstream of the RPT device. The port 9032 may be in fluid connection to
the second end 9004 to determine a pressure of the air in the second opening 9018.
In one form, the port 9032 may be in fluid communication with an interior
of the second opening 9018, such as by forming a fluid connection to an opening in
the interior of the seal portion 9008. The g in the interior of the seal portion
9008 may be in turn in fluid communication with a pressure tap 9036 to the second
opening 9018. Thus the first end 9002 and the second end 9004 may form two fluid
connections therebetween when ted to each other. The port 9032 may provide
an advantage of being able to measure pressure closer to a patient than if pressure is
measured in the RPT device. Due to pressure losses inherent in internal fluid flow as
well as possible leaks throughout the air path from the blower to the patient,
measuring the pressure closer to the patient may e a more accurate
measurement than a pressure measure carried out further from the patient.
Also, the present arrangement allows for the second end 9004 to be
d with respect to the first end 9002 while still maintaining two fluid connections
(i.e. one to deliver the flow of air, another to measure re). This may be
ageous for allowing the fluid conduit 9006 to rotate with respect to the outer
portion 9026, thus reducing torque d on the fluid conduit and/or the outer
portion 9026. Furthermore, such a configuration may also allow a user to t the
first end 9002 and the second end 9004 in one of a plurality of rotational orientations
to each other while maintaining the two fluid connections.
Fig. 6f illustrates the first end 9002 integrated into an RPT device with the
second end 9004 disconnected. Fig. 6g rates the first end 9002 integrated into
the RPT device with the second end 9004 connected.
Although the preceding description generally describes both halves of a
connector system together, e.g., a first end 9002 and a second end 9004, it is to be
understood that the description of either half may be considered in isolation.
It may also be advantageous to ensure that the appropriate masks are used
with the CFV membrane regulated vents. Masks according to examples of the present
technology may be nted masks designed specifically to be compatible with the
CFV membrane regulated venting described above. The system may be designed such
that the flow generator is also compatible with the vent adaptor, meaning that the flow
tor will be programmed to work with a mask system having a constant vent
flow. That is, each mask type (nasal, pillows and full face), may connect to the same
vent adaptor and, therefore, the vent adaptor should allow for enough CO2 t
for each of the mask types. The lowest CO2 washout is generally seen in the full face
mask as there is an increase in the volume of mask dead space. Hence, the vent
adaptor must allow for ient CO2 washout for the full face mask (i.e., the worst
case scenario). Since the system of the t technology, including the flow
generator, vent adaptor, and each mask type, may be designed specifically to work
together, it may be advantageous to prevent non-compatible masks from connecting to
the CFV connector.
As such, a connection mechanism may be provided such that the seal
formed between two ably connecting components is achieved by the connection
mechanism. As previously described, the nasal and pillows mask may connect to a
short tube connector, which will then connect to the vent adaptor. In contrast, the full
face mask may connect ly to the vent adaptor 9100. In another example, the
HME may comprise a separate detachable housing, which could be detached from the
vent adaptor. However, to reduce overall size, the HME may be orated into the
vent adaptor with the CFV unit, wherein the HME slides into the same housing as the
CFV. Such a design means that when the HME is removed there may be an ,
empty space in the CFV housing of the vent adaptor 9100.
In the full face version of a mask ing to the present technology the
short tube connector end may be formed as the inlet of the full face mask. That is, the
same bellows engaging surface is ed as part of the mask shell, which may form
part of the mask plenum chamber.
The bellows sealing membrane may be structured to move under re
such that the membrane moves towards the sealing surface on the opposing connector.
The pressure ted seal may mean that the seal between the CFV unit and the
connector s robust under high res.
The bellows seal may allow for a seal to be formed between the CFV unit
and the connector with minimal friction between the two components, which allows a
swivel connection. For example, sealing using interference fit, a lip seal, a gasket
configuration, or other forms of compression seals between the components may not
allow for easy enough movement between the components such that the components
can swivel, while maintaining a robust seal.
.4.5 Exemplary Vent Adaptors
An example of a vent adaptor 9100 and its components are shown in Figs.
7A-14D. The vent adaptor 9100 according to this example of the present technology
may include a conduit connector 9110, a vent housing 9120, a vent er cover
9130, a membrane 9140, a CFV ring 9150, a vent housing connector 9160, a heat and
moisture exchanger (HME) clip 9170, a HME housing 9180, a bellows seal 9190, and
a vent adaptor connector 9200.
The vent housing 9120 may include an end 9121 with protrusions 9122 to
connect the vent housing 9120 to the conduit connector 9110 at a vent adaptor end
9112. The end 9121 may define the central orifice of the vent g 9120 through
which the flow of pressurized gas is provided to the patient. The vent g 9120
may include external vent holes 9125 and internal vent holes 9126 that define
passageways for venting pressurized gas from the RPT , i.e., gas may be
discharged from the al vent holes 9126, through said passageways, to the
external vent holes 9125, and out to atmosphere. The vent housing 9120 may also
include a tab 9123 joined to a lip 9124 via a support 9128 to releasably attach the vent
housing 9120 to the vent housing connector 9160 and the vent adaptor connector
9200. The patient may actuate the tab 9123 to depress the support 9128 such that the
lip 9124 is disengaged from the vent housing connector 9160 and the vent adaptor
connector 9200. When attached, the lip 9124 allows the vent g 9120 to rotate
relative to the vent adaptor connector 9200 while remaining connected. The vent
housing 9120 may also a shoulder 9127 to fit into a corresponding notch 9164 of the
vent housing connector 9160. The vent g 9120 may also include notches 9129
to receive corresponding s seal connectors 9191 that attach the s seal
9190 to the vent housing 9120 to seal the or of the vent adaptor 9100 against the
vent adaptor connector 9200 when assembled.
The vent housing connector 9160 may include a first bar 9161 and a
second bar 9162 that form a receptacle 9163 that receives a corresponding lip 9124 of
the vent housing 9120 to attach the vent housing connector 9160 to the vent housing
9120. The notch 9164 also receives the shoulder 9127 of the vent housing 9120, as
described above. The vent g connector 9160 may also include a curved outer
surface 9165.
The s seal 9190 may be a bellows seal similar to the features
described above in relation to Figs. 6A-6H. The bellows seal 9190 may have a
shoulder surface 9194 with bellows seal tors 9191 to attach the bellows seal
9190 to the notches 9129 of the vent housing 9120. The bellows seal 9190 may also
have an inner surface 9193 that is contacted by the pressurized gas and urged outward
such that an outer surface 9192 forms a seal against the vent adaptor connector 9200
when assembled.
The vent adaptor connector 9200 may have an orifice 9201 through which
pressurized gas passes from the vent adaptor 9100 and on to the patient during
therapy. Also, the exhaled gas may be discharged into the vent adaptor 9100 via the
orifice 9201. The vent adaptor connector 9200 may be connected at the orifice 9201
to the patient interface via another tube (not shown). The vent adaptor connector 9200
may also have a rim 9202 to connect to the lip(s) 9124 of the vent g 9120 to
allow the vent housing 9120 to t to and rotate relative to the vent adaptor
connector 9200. It should be understood that in another form of the present
technology, the vent adaptor connector 9200 may be connected directly to the t
interface or it may be formed integrally with the patient interface, e.g., the mask shell.
The vent adaptor 9100 may also include an HME clip 9170 and an HME
housing 9180 to retain HME material within the vent adaptor 9100 in a position that is
between the internal vent holes 9126 and the patient, as bed above. The HME
material (not shown) may be a coiled or cylindrical ure that is inserted into the
HME housing 9180 and retained n by the HME clip 9170. The HME clip 9170
may have a pair of arms 9171 extending from a central shaft 9172. The central shaft
9172 may extend through the center of the HME material to secure a shaft end 9173
into a receiver 9183 suspended on a cross-member 9182 of the HME housing 9180 to
secure the HME material inside of the HME housing 9180. The HME housing 9180
may also include a pair of slots 9181 in an outer wall 9184 that correspond to the arms
9171 and receive arm ends 9174 such that when assembled the HME clip 9170 does
not rotate relative to the HME housing 9180. Thus, the HME material would be
secured between the arms 9171 and the cross-member 9182. The outer wall 9184 may
include a plurality of cut-outs 9185.
The conduit tor 9110 may include the vent adaptor end 9112 and a
t end 9111. As explained above, the vent adaptor end 9112 may connect to the
vent g 9120 and the conduit end may be connected to a conduit (not shown)
that is connected at the other end to an RPT device to receive a flow of pressurized
gas. The t connector 9110 may also include anti-asphyxia valve (AAV)
openings 9113.
Another example of a vent r 9100 and its components are shown in
Figs. 15A-15F. This example includes may features similar to the examples shown in
Figs. 7A-14D above. In this example, the vent adaptor tor 9200 includes a rim
9203 that connects to the tab 9123 of the vent housing 9120 to connect the vent
adaptor connector 9200 to the vent housing 9120. Also, this example shows an antiasphyxia
valve (AAV) 9135 that may installed in the conduit connector 9110. The
conduit connector 9110 may also have a ring 9115 to connect to a conduit (not
shown). Also, in this example the bellows seal 9190 can be seen attached to the vent
housing connector 9160. The vent g connector 9160 also has a ridge to allow
for attachment to the vent housing 9120 by the tab 9123. Furthermore, examples of
HME material 9145 and the diffuser 9146 are shown.
Another example of a vent adaptor 9100 and its components are shown in
Figs. 21A-21F. This example includes may features similar to the examples shown in
Figs. 7A-14D and Figs. 15A-15F above. In this example, the HME housing 9180 is
not completely contained inside of the vent adaptor 9100. , it is exposed
partially such that it forms part of the structure that connects the vent housing 9120 to
the vent adaptor connector 9200.
Another example of a vent r 9100 and its components are shown in
Fig. 22. This example includes may features similar to the examples shown in Figs.
7A-14D and Figs. 15A-15F above. Fig. 22 also includes a flap retaining structure
9141 that may be attached to the HME clip 9170 on one side and abut the flap 9140
on the other side to hold the flap 9140 in an operational position relative to the vent
housing 9120.
Another e of a vent adaptor 9100 and its components are shown in
Figs. 24A-24B. This example es may es similar to the examples shown in
Figs. 7A-14D and Figs. 15A-15F above.
Fig. 23 depicts a diagram of the ways the vent adaptor 9100 may be
attached to different patient interfaces. In the case of the nasal cushion patient
interface 3000A or the nasal pillows patient interface 3000B, the vent adaptor 9100
may be joined to either patient ace via a short tube 9210. One end of the short
tube 9210 may be joined to the patient interface 3000A, 3000B and the other end may
be joined to the vent adaptor connector 9200 described above. atively, in the
case of the full face patient interface 3000C, the vent adaptor 9100 does not e
the vent adaptor connector 9200 and the vent adaptor 9100 is connected directly to the
full face patient interface 3000C such that no short tube 9210 is provided.
Figs. 33A to 33I depict another example of a vent adaptor 9100 according
to an e of the present technology. This vent adaptor 9100 may be connected to
a patient interface 3000, as shown in Fig. 35 for example, to provide the functions of
its components.
The vent adaptor includes an elbow assembly 9220 to e a fluid
connection with the patient interface 3000, e.g., via a tion port 3600 on the
plenum chamber 3200. This example of the elbow assembly 9220 includes an elbow
frame 9222 and an elbow overmould 9224. The elbow assembly 9220 may provide a
releasable connection with the plenum chamber 3200 at the connection port. The
elbow frame 9222 may include tabs that are cally deformable for the releasable
connection and the elbow uld 9224 may provide a fluid-tight seal around
openings in the elbow frame 9222, as well as added resiliency for the elbow frame
9222. The elbow assembly 9220 may also be rotatable relative to the plenum chamber
3200 to reduce the effects of tube drag from the other ents of the vent adaptor
9100 and the air circuit 4170. The elbow ly 9220 may also be removably
connected to a patient interface 3000 and may be able to swivel relative to the patient
interface 3000.
The vent adaptor 9100 may also include a short tube assembly 9210. The
short tube assembly 9210 may decouple the other components of the vent adaptor
9110, e.g., the vent housing 9320 and the vent core structure 9300, from the elbow
assembly’s 9220 connection with the plenum chamber 3200. By decoupling the other
components of the vent adaptor 9110 in this manner, the mass that must be carried
directly on the patient’s head via the patient interface 3000 can be reduced, which in
turn provides a lighter and more comfortable experience for the patient. The short
tube assembly 9210 may include a tube 9212, which may be comprised of one or
more helical coils. The short tube assembly 9210 may include a tube-elbow connector
9216 to provide a connection with the elbow assembly 9220. The connection between
the tube-elbow connector 9216 and the elbow assembly 9220 may comprise a snapfit.
The connection between the tube-elbow connector 9216 and the elbow assembly
9220 may be permanent – in other words, the connection may not be separated
without damaging the ents. The short tube assembly 9210 may include a tubehousing
tor 9214 to provide a connection with the vent g connector
9160. The connection n the tube-housing connector 9214 and the vent housing
connector 9160 may se a snap-fit. The connection between the tube-housing
connector 9214 and the vent housing connector 9160 may be permanent – in other
words, the tion may not be separated without damaging the components.
The vent adaptor 9100 may e a vent g connector 9160 to join
the short tube assembly 9210 with the vent housing 9320. As described above, the
vent housing connector 9160 may be joined to the short tube assembly 9210 with the
tube-housing connector 9214 that may be a snap-fit and that may be permanent. The
vent g connector 9160 may also include a bayonet connector 9166 to facilitate
a releasable bayonet-style connection with the vent housing 9320 or a heat and
moisture exchanger (HME) housing 9400 such as those shown in Figs. 38A to 39C.
Thus the HME associated with the HME housing 9400 may be optional and, as such,
is not shown in Figs. 33A to 33F. The bayonet connectors 9166 may be male or
female. Also, making the vent housing 9320 removably connectable to the vent
housing connector 9160 allows the vent components to be removed and disassembled
for cleaning.
The HME housing 9400 may also be at least partially enclosed within the
vent adaptor 9100. Figs. 33G to 33I depict examples of the vent adaptor 9100 of Figs.
33A to 33F with the HME housing 9400 ed therein. The example depicted in
the cross-sectional view of Fig. 33G and in the exploded view of Fig. 33I include the
HME housing 9400 of Figs. 38A to 38C. The example depicted in the sectional
view of Fig. 33H includes the HME housing 9400 of Figs. 39A to 39C. The examples
shown in Figs. 33G to 33I omit the HME material 9145 so that features of the vent
r 9100 and the HME housing 9400 are not obstructed in the drawings.
r, it should be understood that the HME material 9145 may be ed
therein when the vent adaptor 9100 is used for therapy. Fig. 33F shows the vent
adaptor 9100 without the HME housing 9400 and Figs. 33G and 33H show the vent
adaptor 9100 with the HME housing 9400 – it should be understood that the vent
housing tor 9160 and the vent housing 9320 connect the same way, as
described above, regardless of whether the HME housing 9400 is present.
The HME housing 9400 is shown in these examples led within a
cavity 9167 that is defined at least in part by the vent housing connector 9160 and/or
the vent housing 9320. When the vent housing tor 9160 and the vent housing
9320 are joined together, the cavity 9167 is formed. Alternatively, the vent housing
connector 9160 or the vent housing 9320 may comprise ntially all of the cavity
9167. If the HME housing 9400 is not provided, the cavity 9167 may be empty, as
shown in Fig. 33F. The vent housing 9320 and the vent housing connector 9160 may
be shaped and dimensioned such that exterior es of the HME housing 9400 are
in direct contact with or adjacent to interior surfaces of the vent housing 9320 and the
vent housing connector 9160. The HME housing 9400 may occupy ntially all of
the cavity 9167 when installed therein.
The vent housing 9320 or the vent housing connector 9160 may also
include a structure to facilitate a removable connection with a corresponding structure
of the HME housing 9400. For example, the interior of the vent housing 9320 may
also include an annular lip 9326 around all or part of the inner periphery of the vent
housing 9320. The annular lip 9326 may include at least one ing protrusion 9328
to removably t the HME g 9400 to the vent g 9320. Fig. 34C
shows an example of the vent housing 9320 with four retaining protrusions 9328. The
retaining protrusions 9328 are also spaced approximately evenly around the annular
lip 9326 in Fig. 34C. The HME housing 9400 may also include an annular recess
9405 around the outer periphery of the atmosphere-side HME housing portion 9404
that removably es the retaining protrusions 9328. The annular recess 9405 may
be continuous about the outer periphery of the atmosphere-side HME housing portion
9404, which allows the HME housing 9400 to be attached to the vent g 9320
without regard to the relative orientation of the components.
The removable connection between the annular recess 9405 and the
ing protrusions 9328 may be a snap-fit or a friction fit. The removable
connection between the annular recess 9405 and the ing protrusions 9328 may
be sufficiently secure (e.g., due to friction) to prevent relative rotation between the
HME housing 9400 and the vent housing 9320, while allowing the patient or a
clinician to manually separate the components for replacement and/or cleaning.
An alternative arrangement is also envisioned in the outer periphery of the
HME housing 9400 includes protrusions that may be removably received by a recess
around the inner ery of the vent housing 9320. It is also envisioned that the
removable connection interface between the HME housing 9400 and the vent adaptor
9100 may occur n the patient-side HME housing portion 9402 and the vent
housing connector 9160, instead of between the atmosphere-side HME housing
n 9404 and the vent housing 9320. Instead of the annular recess 9405 and the
retaining protrusions 9328, it is also envisioned that the HME g 9400 and the
vent adaptor 9100 may each have threads to provide a threaded connection that is
removable. In another alternative, the HME housing 9400 may be connected to the
vent housing connector 9160 or the vent housing 9320 with a t connection.
Alternatively, the HME housing 9400 may be retained by the vent adaptor
9100 by being sandwiched between the vent housing connector 9160 and the vent
housing 9320. There may be no positive connection between the HME housing 9400
and the vent adaptor 9100, and the HME housing 9400 may only be retained by being
ed by the vent housing connector 9160 and the vent housing 9320.
Figs. 34A to 34G show examples of the vent housing 9320, the flap or
membrane 9140, the vent core structure 9300, the diffusing member 9146, the diffuser
retaining ring 9148, and the vent diffuser cover 9330. These ents may be
assembled into a sub-assembly, as shown in Figs. 34A to 34G, and joined to the vent
housing connector 9160 for use. The components of the sub-assembly depicted in
Figs. 34A to 34G may be inseparable via a permanent snap-fit or the ents may
be separable by the user. In the case of inseparability, the snap-fit may be ent
such that the ents cannot be separated without damaging them.
The vent g 9320 may also include bayonet connectors 9322 to
pondingly connect with the bayonet connectors 9166 of the vent g
connector 9160 to removably connect the vent housing 9320 to the vent housing
connector 9160. The vent housing 9320 may also include a ne retainer 9324
to hold the membrane 9140 against the vent core structure 9300 when assembled. The
membrane retainer 9324 may comprise an open, radial, and cage-like structure to
allow the vent flow to travel through the membrane retainer 9324 for rge by the
vent core structure 9300. The membrane retainer 9324 may also be open in its center
to allow the therapy flow to pass along to the patient from the RPT device 4000.
The flap or membrane 9140 may be positioned between the ne
retainer 9324 and the vent core structure 9300. The membrane 9140 may be held in
position between these two structures, but may be otherwise be free to be deformed
by pressure within the vent adaptor 9100. The membrane 9140 may function similarly
to other examples of the membrane 9140 disclosed above.
The vent core structure 9300 may include an inlet 9301 to allow the flow
of gas generated by the RPT device 4000 to pass through the vent adaptor 9100 and
along to the patient for therapy. The vent core structure 9306 may include a vent core
extension 9306 h which the inlet 9301 may be defined. The vent core extension
9306 may extend y and may include air circuit tors 9302 to connect the
vent core 9300 to the air t 4170. As can be seen, the vent core extension 9306 is
shaped and ioned to extend through the diffuser retaining ring 9148, the
diffuser 9146, and the vent diffuser cover 9330 to align these components when the
vent r 9100 is assembled. The vent core structure 9300 may also include clips
9304 on an alignment structure 9312 that connect to the tion surface 9334 of
the vent er cover 9330. The clips 9304 may be connected to the connection
surface 9334 with a snap-fit to allow the vent diffuser cover 9330 to be removed for
disassembly to allow cleaning and/or replacement of vent adaptor components 9100
such as the diffuser 9146. The alignment structure 9312 may also facilitate axial
alignment of the vent core ure 9300 with the diffuser 9146 and the vent diffuser
cover 9330 by virtue of corresponding shapes.
The vent core structure 9300 may also include a plurality of outer orifices
9308 and a plurality of inner orifices 9310. The plurality of inner orifices 9310 may
be configured such that vent flow to atmosphere through the inner orifices 9310 may
be cted or restricted by the membrane 9140 in use. The plurality of outer
orifices 9308 may be ured such that vent flow to atmosphere through the outer
orifices 9308 may not be obstructed or restricted at any point by the membrane 9140
in use. However, the membrane 9140 may also be configured such that it does not
completely occlude the inner orifices 9310 at any pressure at least within a typical
range of therapeutic pressure (e.g., between about 6 cmH2O and about 20 cmH2O). In
other words, vent flow may be discharged through both the inner orifices 9310 and
the outer orifices 9308 at any pressure within a typical range of therapeutic pressure,
while the pressure within the vent adaptor 9110 deforms the membrane 9140 to vary
the proportion of vent flow traveling through the outer orifices 9308 and the inner
orifices 9310 so as to maintain a nt vent flow rate, as described above.
The diffuser 9146 may include a diffuser opening 9147 through which the
vent core extension 9306 may pass. The diffuser 9146 may include similar features to
the diffusers described above.
The diffuser 9146 may be held in position downstream of the inner
orifices 9310 and the outer orifices 9308 relative to the vent flow by the er
retaining ring 9148 and the vent diffuser cover 9330. The diffuser ing ring 9148
may be secured to the vent diffuser cover 9330, e.g., with a it, to retain the
diffuser 9146. The diffuser retaining ring 9148 may include radial diffuser retainers
9149 to hold the diffuser 9146 against the vent diffuser cover 9330. The diffuser
retaining ring 9148 and the radial diffuser retainers 9149 may define posterior vent
outlets 9342 around the vent housing 9320. Vent flow exiting the vent core structure
9300 may pass h the diffuser 9148 and out through the ior vent outlets
9340. The vent diffuser cover 9332 may include a series of cover spacers 9332 spaced
radially about the vent diffuser cover 9330 to define the anterior vent outlets 9342.
Vent flow g the vent core structure 9300 may pass through the er 9148 and
out through the anterior vent outlets 9342.
The exemplary vent adaptor 9100 disclosed above and in Figs. 33A to
34G is shown connected to a patient interface 3000 in Fig. 35. The elbow assembly
9220 is excluded in this example, because the plenum chamber 3200 includes a
connection port 3600 that is angled so as to point in an inferior direction relative to
the patient’s head in use, thereby directing the vent adaptor 9100 away from the
patient’s head. Also, the short tube assembly 9210 may be permanently connected to
the plenum chamber 3200 at the connection port 3600.
Figs. 37A to 37E depict another example of a vent adaptor 9100 according
to the present technology. The vent adaptor 9100 may include a plenum chamber
tor 9700 to connect the vent adaptor 9100 directly to the connection port 3600
of the plenum chamber 3200 and/or to a shroud 3305 thereof (see Fig. 41) to provide
a fluid connection for the flow of pressurized gas from the vent adaptor 9100 to the
plenum chamber 3200.
The vent adaptor 9100 may also e a baffle 9600. The baffle 9600
may separate the incoming flow of pressurized gas from the RPT device 4000 from
the outgoing vent flow exiting via the outer orifices 9308 and the inner orifices 9310
of the vent housing 9120. The baffle 9600 may be positioned internally of the plenum
r connector 9700. The baffle 9600 and the plenum chamber connector 9700
may be aligned when connected to form concentric circles.
The vent adaptor 9100 may also include a lip seal 9500 that fits around the
exterior periphery of the plenum chamber connector 9700. The lip seal 9500 may
form a seal with the interior periphery of the connection port 3600 of the plenum
r 3200 and/or the shroud 3305 thereof to provide a pneumatic seal while allow
rotation of the vent adaptor 9100 relative to the patient interface 3000.
The vent adaptor 9140 may also include the flap or membrane 9140 to
regulate the vent flow through the inner orifices 9310 and the outer orifices 9308 of
the vent housing 9120 in accordance with the examples described above, e.g., the
examples pictured in Figs. 33A to 34G.
The vent housing 9120 may include inner orifices 9310 and outer orifices
9308 and these orifices may permit vent flow to exit the vent r 9100 to
atmosphere, as described in the examples above such as the examples of Figs. 33A to
The vent housing 9120 may also include tabs 9123 and lips 9124 to
provide a releasable and rotatable connection with the connection port 3600 of the
plenum chamber 3200 and/or the shroud 3305 thereof. The tabs 9123 may be
manually depressed to release the lips 9123 from a ponding r protrusion
(not shown) of the connection port 3600 of the plenum chamber 3200 and/or the
shroud 3305 thereof. When connected, the lips 9124 allow the vent adaptor 9100 to
maintain a connection with the connection port 3600 of the plenum chamber 3200
and/or the shroud 3305 thereof while being ble to reduce the effects of tube
drag.
The vent housing 9120 may be connected to a conduit connector 9110 that
in turn may t the vent adaptor 9100 to an air circuit. The t connector
9110 may be in the form of an elbow. The conduit connector 9110 may have a
t end 9111 that connects to the air circuit 4170 and a vent adaptor end 9112 that
connects to the vent g 9120. The tion between the vent adaptor end 9112
of the conduit connector 9110 and the vent housing 9120 may comprise a snap-fit,
may be permanent such that the connection cannot be separated without damaging at
least one of the components, and/or may be non-rotatable to prevent the conduit
connector 9110 from contacting the tabs 9123. The conduit tor 9110 may also
include one or more anti - asphyxia valve (AAV) openings 9113 for the AAV 9135.
The vent adaptor 9100 may also include an air circuit connector 9116 that
may be attached to the conduit end 9111 of the conduit connector 9110. The air circuit
connector 9116 may include bayonet connectors 9117 to correspondingly connect to
the connectors 4175 of the exemplary air circuit 4170 of Figs. 36A to 36C. The
connection between the air circuit connector 9116 and the air circuit 4170 may be
releasable.
The vent adaptor depicted in Figs. 37A to 37E may not e heat and
moisture ger (HME) al 9145. The absence of a heat and moisture
exchanger material 9145 positioned within the vent flow path may minimise vent flow
impedance, thereby minimising CO2 build up within the plenum chamber 3200. The
depicted vent adaptor 9100 may be, for example, suitable for use with a full face
patient interface as depicted in Fig. 41.
The vent adaptor 9100 depicted in Figs. 37A to 37E may form an elbow
assembly that may be removably connected to a patient interface 3000, e.g., as shown
in Fig. 41, and may be able to swivel relative to the patient interface.
Figs. 40 and 41 show further examples of vent adaptors 9100 joined to
patient interfaces 3000.
Fig. 40 depicts a patient interface 3000 with a seal-forming structure 3100
that forms a seal around only the patient’s nose in use (i.e., a nasal mask). The vent
adaptor 9100 is shown joined to a shroud 3305 that covers a portion of the plenum
chamber 3200. In this example, the vent adaptor 9100 features are combined in an
elbow that is attached ly and rotatably to the shroud 3305 to e a fluid
tion with the plenum chamber 3200. However, it should be understood that the
vent adaptor of Figs. 33A to 33I could be attached to the shroud 3305 to form a fluid
connection with the plenum chamber 3200 via the elbow assembly 9220. The shroud
3305 has rigidiser arms 3301 joined to the shroud 3305 at hinges 3307. The lateral
arms 3301 may include superior attachment points 3302 and or ment
points 3304 to attach straps of a positioning and stabilising structure 3300. The
superior attachment points 3302 may form loops through which superior straps can be
passed and the inferior attachment points 3304 may receive clips 3306, which in turn
receive or straps.
Fig. 40 depicts an exemplary patient interface 3000 that may include a
seal-forming structure 3100 to form a seal over the patient’s nose and mouth in use.
The vent adaptor 9100, such as the example depicted in Figs. 37A to 37E, may be
connected to the shroud 3305 to provide a fluid connection with the plenum chamber
3200. The shroud 3305 may be joined to ser arms 3301 that may have superior
attachment points 3302 to attach straps of a positioning and stabilising structure 3300.
The shroud 3305 may be ted to inferior strap connectors 3303 separate from
the rigidiser arms 3301 to attach straps of a positioning and stabilising structure 3300
at inferior attachment points 3304. The superior attachment points 3302 may form
loops through which superior straps can be passed and the inferior attachment points
3304 may receive clips 3306, which in turn receive inferior straps.
.5 RPT DEVICE
An RPT device 4000 in accordance with one aspect of the present
technology comprises mechanical and pneumatic ents 4100, electrical
components 4200 and is configured to execute one or more algorithms 4300. The RPT
device may have an al housing 4010, formed in two parts, an upper portion
4012 and a lower portion 4014. Furthermore, the external housing 4010 may include
one or more panel(s) 4015. The RPT device 4000 comprises a chassis 4016 that
supports one or more internal components of the RPT device 4000. The RPT device
4000 may include a handle 4018.
The pneumatic path of the RPT device 4000 may comprise one or more
air path items and mufflers 4120, e.g., an inlet air filter 4112, an inlet muffler 4122, a
re generator 4140 capable of supplying air at positive re (e.g., a blower
4142), an outlet muffler 4124 and one or more transducers 4270, such as pressure
sensors and flow rate sensors.
One or more of the air path items may be located within a removable
unitary structure which will be ed to as a tic block 4020. The pneumatic
block 4020 may be located within the external housing 4010. In one form a pneumatic
block 4020 is supported by, or formed as part of the chassis 4016.
The RPT device 4000 may have an electrical power supply 4210, one or
more input devices 4220, a l controller 4230, a therapy device controller 4240, a
re generator 4140, one or more protection circuits 4250, memory 4260,
transducers 4270, data communication interface 4280 and one or more output devices
4290. ical components 4200 may be mounted on a single Printed t Board
Assembly (PCBA) 4202. In an ative form, the RPT device 4000 may e
more than one PCBA 4202.
.5.1 RPT device mechanical & pneumatic components
An RPT device may comprise one or more of the following components
in an integral unit. In an alternative form, one or more of the following components
may be located as respective separate units.
.5.1.1 Air (s)
An RPT device in accordance with one form of the present technology
may include an air filter 4110, or a plurality of air filters 4110.
In one form, an inlet air filter 4112 is located at the beginning of the
pneumatic path upstream of a pressure generator 4140. See Fig. 4B.
In one form, an outlet air filter 4114, for example an antibacterial filter, is
located between an outlet of the pneumatic block 4020 and a patient interface 3000.
See Fig. 4B.
.5.1.2 Muffler(s)
In one form of the present technology, an inlet muffler 4122 is located in
the pneumatic path upstream of a re generator 4140. See Fig. 4B.
In one form of the present technology, an outlet muffler 4124 is located in
the pneumatic path between the pressure generator 4140 and a patient interface 3000.
See Fig. 4B.
.5.1.3 Pressure generator
In one form of the present technology, a pressure generator 4140 for
producing a flow, or a supply, of air at positive re is a controllable blower 4142.
For example the blower 4142 may include a brushless DC motor 4144 with one or
more ers housed in a volute. The blower may be capable of delivering a supply
of air, for e at a rate of up to about 120 litres/minute, at a positive pressure in a
range from about 4 cmH2O to about 20 cmH2O, or in other forms up to about 30
cmH2O. The blower may be as described in any one of the following patents or patent
applications the contents of which are incorporated herein by reference in their
entirety: U.S. Patent No. 7,866,944; U.S. Patent No. 8,638,014; U.S. Patent No.
8,636,479; and PCT Patent Application Publication No.
The pressure generator 4140 is under the control of the therapy device
controller 4240.
In other forms, a pressure generator 4140 may be a piston-driven pump, a
pressure regulator connected to a high pressure source (e.g. compressed air reservoir),
or a bellows.
.5.1.4 Transducer(s)
Transducers may be al of the RPT device, or external of the RPT
device. External transducers may be located for example on or form part of the air
circuit, e.g., the patient ace. External ucers may be in the form of noncontact
sensors such as a Doppler radar movement sensor that transmit or transfer
data to the RPT device.
In one form of the present technology, one or more transducers 4270 are
located upstream and/or downstream of the pressure tor 4140. The one or more
transducers 4270 may be constructed and arranged to measure properties such as a
flow rate, a pressure or a temperature at that point in the pneumatic path.
In one form of the t technology, one or more transducers 4270 may
be located ate to the patient interface 3000.
In one form, a signal from a transducer 4270 may be filtered, such as by
low-pass, high-pass or band-pass filtering.
.5.1.4.1 Flow rate sensor
A flow rate sensor in accordance with the present technology may be
based on a differential pressure transducer, for example, an SDP600 Series
differential pressure ucer from SENSIRION.
In one form, a signal representing a flow rate such as a total flow rate Qt
from the flow rate sensor is received by the central controller 4230.
.5.1.4.2 Pressure sensor
A pressure sensor in accordance with the t technology is located in
fluid communication with the pneumatic path. An e of a suitable pressure
transducer is a sensor from the ELL ASDX series. An alternative suitable
pressure transducer is a sensor from the NPA Series from GENERAL ELECTRIC.
In one form, a signal from the pressure sensor is received by the central
controller 4230.
.5.1.4.3 Motor speed transducer
In one form of the present technology a motor speed transducer is used to
determine a rotational velocity of the motor 4144 and/or the blower 4142. A motor
speed signal from the motor speed transducer may be provided to the therapy device
controller 4240. The motor speed transducer may, for example, be a speed sensor,
such as a Hall effect sensor.
.5.1.5 Anti-spill back valve
In one form of the present logy, an anti-spill back valve 4160 is
located between the humidifier 5000 and the pneumatic block 4020. The anti-spill
back valve 4160 is constructed and ed to reduce the risk that water will flow
upstream from the humidifier 5000, for example to the motor 4144.
.5.1.6 Air t
An air circuit 4170 in accordance with an aspect of the present technology
is a conduit or a tube constructed and arranged in use to allow a flow of air to travel
between two components such as the pneumatic block 4020 and the patient interface
3000.
In particular, the air circuit 4170 may be in fluid connection with the
outlet of the pneumatic block and the patient interface. The air circuit may be referred
to as an air delivery tube. In some cases there may be separate limbs of the circuit for
tion and exhalation. In other cases a single limb is used.
In some forms, the air circuit 4170 may comprise one or more heating
elements ured to heat air in the air circuit, for example to maintain or raise the
temperature of the air. In other words, the air t 4170 may be a heated air circuit
4171. The heating element may be in a form of a heated wire circuit, and may
comprise one or more ucers, such as temperature sensors. In one form, the
heated wire circuit may be helically wound around the axis of the air circuit 4170. The
heating element may be in communication with a controller such as a central
controller 4230. One example of an air circuit 4170 comprising a heated wire circuit
is described in United States Patent Application No. US/2011/0023874, which is
incorporated herewithin in its entirety by reference.
Figs. 36A to 36C depict examples of an air circuit 4170 according to an
example of the t technology. The air circuit 4170 may include a tube 4172 that
is comprised of one or more helical coils. The air circuit 4173 may include an RPT
device connector 4173 at one end that is configured to connect to an RPT device 4000
to receive the flow of pressurized gas. At the other end, the air circuit 4170 may
include a vent adaptor connector 4174 that may be ted to a vent adaptor 9100,
such as in the examples disclosed in Figs. 33A to 34G. The vent adaptor connector
4174 may include connectors 4175 to join with corresponding air circuit connectors
9302 of the vent adaptor 9300. The connectors 4175 may be in the form of female
bayonet connectors that correspond to the air circuit tors 9302. The vent
adaptor tor 4174 may also include grip recesses 4176 to allow the patient to
grip the vent adaptor connector 4174 to rotate the air circuit 4170 to connect to or
nect from the vent adaptor 9100. The vent adaptor connector 4174 may also
include a seal 4177 to form a pneumatic seal between the vent adaptor tor 4174
and a tube tor 4178 that connects the vent adaptor connector 4174 to the tube
4172.
.5.1.7 Oxygen delivery
In one form of the present technology, supplemental oxygen 4180 is
delivered to one or more points in the pneumatic path, such as upstream of the
pneumatic block 4020, to the air circuit 4170 and/or to the t ace 3000.
.5.2 RPT device electrical components
.5.2.1 Power supply
A power supply 4210 may be located al or external of the external
g 4010 of the RPT device 4000.
In one form of the present technology, power supply 4210 provides
electrical power to the RPT device 4000 only. In another form of the present
technology, power supply 4210 provides electrical power to both RPT device 4000
and humidifier 5000.
.5.2.2 Input devices
In one form of the present technology, an RPT device 4000 includes one
or more input devices 4220 in the form of buttons, switches or dials to allow a person
to interact with the device. The buttons, switches or dials may be physical devices, or
software devices accessible via a touch screen. The s, switches or dials may, in
one form, be physically connected to the external housing 4010, or may, in r
form, be in wireless communication with a receiver that is in electrical connection to
the central controller 4230.
In one form, the input device 4220 may be constructed and arranged to
allow a person to select a value and/or a menu option.
.5.2.3 Central controller
In one form of the present technology, the central controller 4230 is one or
a plurality of processors suitable to l an RPT device 4000.
Suitable processors may include an x86 INTEL sor, a processor
based on ARM® Cortex®-M processor from ARM Holdings such as an STM32
series microcontroller from ST MICROELECTRONIC. In certain ative forms of
the present technology, a 32-bit RISC CPU, such as an STR9 series microcontroller
from ST MICROELECTRONICS or a 16-bit RISC CPU such as a processor from the
MSP430 family of microcontrollers, manufactured by TEXAS INSTRUMENTS may
also be suitable.
In one form of the t technology, the central controller 4230 is a
ted electronic circuit.
In one form, the central controller 4230 is an application-specific
integrated circuit. In r form, the central controller 4230 comprises discrete
onic components.
The central controller 4230 may be configured to receive input signal(s)
from one or more transducers 4270, one or more input s 4220, and the
fier 5000.
The central controller 4230 may be configured to provide output signal(s)
to one or more of an output device 4290, a therapy device controller 4240, a data
communication interface 4280, and the humidifier 5000.
In some forms of the present technology, the central controller 4230 is
configured to implement the one or more methodologies described herein, such as the
one or more algorithms 4300 sed as computer programs stored in a nontransitory
computer readable storage medium, such as memory 4260. In some forms
of the present technology, the central controller 4230 may be ated with an RPT
device 4000. However, in some forms of the present technology, some
methodologies may be performed by a ly located device. For example, the
remotely located device may determine control settings for a ventilator or detect
respiratory related events by analysis of stored data such as from any of the sensors
described herein.
.5.2.4 Clock
The RPT device 4000 may include a clock that is connected to the central
controller 4230.
.5.2.5 Therapy device controller
In one form of the present technology, a therapy device 4350 may include
a therapy device controller 4240 is a therapy control module 4330 that forms part of
the algorithms 4300 executed by the central controller 4230.
In one form of the present technology, therapy device controller 4240 is a
dedicated motor control integrated circuit. For example, in one form a MC33035
brushless DC motor controller, manufactured by ONSEMI is used.
.5.2.6 Protection circuits
The one or more protection circuits 4250 in ance with the present
logy may comprise an electrical protection circuit, a ature and/or
pressure safety circuit.
.5.2.7 Memory
In accordance with one form of the present logy the RPT device
4000 includes memory 4260, e.g., non-volatile memory. In some forms, memory
4260 may include battery powered static RAM. In some forms, memory 4260 may
include volatile RAM.
Memory 4260 may be located on the PCBA 4202. Memory 4260 may be
in the form of EEPROM, or NAND flash.
Additionally or alternatively, RPT device 4000 includes a removable form
of memory 4260, for e a memory card made in accordance with the Secure
Digital (SD) standard.
In one form of the t logy, the memory 4260 acts as a nontransitory
computer readable storage medium on which is stored computer program
ctions expressing the one or more methodologies described herein, such as the
one or more algorithms 4300.
.5.2.8 Data communication systems
In one form of the present technology, a data communication interface
4280 is provided, and is connected to the central ller 4230. Data communication
interface 4280 may be connectable to a remote external communication network
and/or a local external communication network. The remote external communication
network may be connectable to a remote external device. The local external
ication network may be connectable to a local external device.
In one form, data communication interface 4280 is part of the central
ller 4230. In another form, data communication interface 4280 is separate from
the central controller 4230, and may comprise an integrated circuit or a processor.
In one form, remote external ication network is the Internet. The
data communication interface 4280 may use wired communication (e.g. via Ethernet,
or optical fibre) or a wireless protocol (e.g. CDMA, GSM, LTE) to connect to the
Internet.
In one form, local external communication k utilises one or more
communication standards, such as Bluetooth, or a consumer infrared protocol.
In one form, remote external device is one or more computers, for
example a cluster of networked computers. In one form, remote external device may
be virtual computers, rather than physical computers. In either case, such a remote
external device may be ible to an appropriately authorised person such as a
clinician.
The local al device may be a personal computer, mobile phone,
tablet or remote control.
.5.2.9 Output devices including optional display, alarms
An output device 4290 in ance with the present technology may
take the form of one or more of a visual, audio and haptic unit. A visual display may
be a Liquid Crystal Display (LCD) or Light ng Diode (LED) display.
9.1 Display driver
A display driver receives as an input the characters, symbols, or images
intended for display on the display, and converts them to commands that cause the
display to display those characters, symbols, or images.
9.2 Display
A display is configured to visually y characters, symbols, or images
in response to commands received from the display driver. For example, the display
may be an eight-segment display, in which case the display driver converts each
character or symbol, such as the figure “0”, to eight logical signals indicating whether
the eight respective segments are to be activated to display a particular ter or
symbol.
.5.3 RPT device thms
.5.3.1 Pre-processing module
A pre-processing module 4310 in accordance with one form of the present
logy receives as an input a signal from a transducer 4270, for e a flow
rate sensor or pressure sensor, and performs one or more process steps to calculate
one or more output values that will be used as an input to another module, for
example a therapy engine module 4320.
In one form of the present technology, the output values include the
ace or mask re Pm, the respiratory flow rate Qr, and the leak flow rate Ql.
In various forms of the present technology, the pre-processing module
4310 comprises one or more of the following algorithms: pressure compensation
4312, vent flow rate estimation 4314, leak flow rate estimation 4316, and respiratory
flow rate estimation 4318.
.5.3.1.1 Pressure compensation
In one form of the present technology, a pressure compensation algorithm
4312 receives as an input a signal indicative of the pressure in the pneumatic path
proximal to an outlet of the tic block. The pressure compensation algorithm
4312 estimates the pressure drop through the air circuit 4170 and provides as an
output an estimated pressure, Pm, in the patient interface 3000.
.5.3.1.2 Vent flow rate estimation
In one form of the present technology, a vent flow rate estimation
algorithm 4314 es as an input an estimated pressure, Pm, in the patient interface
3000 and estimates a vent flow rate of air, Qv, from a vent 3400 in a patient ace
3000.
.5.3.1.3 Leak flow rate tion
In one form of the present technology, a leak flow rate estimation
algorithm 4316 receives as an input a total flow rate, Qt, and a vent flow rate Qv, and
provides as an output an estimate of the leak flow rate, Ql, . In one form, the leak
flow rate estimation algorithm estimates the leak flow rate Ql by calculating an
average of the difference n total flow rate Qt and vent flow rate Qv over a
period iently long to include l breathing cycles, e.g. about 10 seconds.
In one form, the leak flow rate estimation algorithm 4316 receives as an
input a total flow rate Qt, a vent flow rate Qv, and an estimated pressure, Pm, in the
patient interface 3000, and provides as an output a leak flow rate Ql, by calculating a
leak conductance, and determining a leak flow rate Ql to be a function of leak
conductance and pressure, Pm. Leak conductance is calculated as the quotient of low
pass filtered non-vent flow rate equal to the difference between total flow rate Qt and
vent flow rate Qv, and low pass filtered square root of pressure Pm, where the low
pass filter time constant has a value sufficiently long to include several breathing
cycles, e.g. about 10 seconds. The leak flow rate Ql may be estimated as the product
of leak conductance and a function of pressure, Pm.
.5.3.1.4 atory flow rate tion
In one form of the present technology, a respiratory flow rate estimation
algorithm 4318 receives as an input a total flow rate, Qt, a vent flow rate, Qv, and a
leak flow rate, Ql, and estimates a respiratory flow rate of air, Qr, to the patient, by
subtracting the vent flow rate Qv and the leak flow rate Ql from the total flow rate Qt.
.5.3.2 Therapy Engine Module
In one form of the present technology, a therapy engine module 4320
receives as inputs one or more of a pressure, Pm, in a patient interface 3000, and a
respiratory flow rate of air to a patient, Qr, and provides as an output one or more
therapy parameters.
In one form of the present technology, a therapy parameter is a treatment
pressure Pt.
In one form of the present technology, therapy ters are one or more
of a level of pressure support, a base pressure, and a target ventilation.
In various forms, the therapy engine module 4320 comprises one or more
of the ing algorithms: phase determination 4321, waveform determination
4322, ventilation determination 4323, atory flow tion determination 4324,
apnea / hypopnea determination 4325, snore determination 4326, airway patency
ination 4327, target ventilation determination 4328, and therapy parameter
determination 4329.
.5.3.2.1 Phase determination
In one form of the present technology, the RPT device 4000 does not
determine phase.
In one form of the present technology, a phase determination algorithm
4321 receives as an input a signal indicative of atory flow rate, Qr, and provides
as an output a phase of a current breathing cycle of a patient 1000.
In some forms, known as discrete phase determination, the phase output
is a discrete variable. One implementation of te phase determination provides a
bi-valued phase output with values of either inhalation or exhalation, for example
represented as values of 0 and 0.5 revolutions respectively, upon detecting the start of
spontaneous inhalation and exhalation respectively. RPT devices 4000 that er”
and “cycle” effectively m discrete phase determination, since the r and
cycle points are the instants at which the phase changes from exhalation to inhalation
and from inhalation to exhalation, respectively. In one implementation of bi-valued
phase determination, the phase output is determined to have a discrete value of 0
(thereby “triggering” the RPT device 4000) when the respiratory flow rate Qr has a
value that exceeds a positive threshold, and a discrete value of 0.5 revolutions
(thereby “cycling” the RPT device 4000) when a respiratory flow rate Qr has a value
that is more negative than a negative threshold.
Another implementation of discrete phase determination provides a ued
phase output with a value of one of inhalation, mid-inspiratory pause, and
exhalation.
In other forms, known as continuous phase determination, the phase
output is a continuous variable, for example varying from 0 to 1 revolutions, or 0 to
2 radians. RPT devices 4000 that perform uous phase determination may
trigger and cycle when the continuous phase reaches 0 and 0.5 revolutions,
tively. In one implementation of continuous phase determination, a continuous
value of phase is determined using a fuzzy logic analysis of the respiratory flow
rate Qr. A continuous value of phase deter mined in this entation is often
referred to as “fuzzy phase”. In one implementation of a fuzzy phase determination
algorithm 4321, the following rules are applied to the respiratory flow rate Qr:
1. If the respiratory flow rate is zero and increasing fast then the phase is 0
revolutions.
2. If the respiratory flow rate is large ve and steady then the phase is 0.25
revolutions.
3. If the atory flow rate is zero and falling fast, then the phase is 0.5
revolutions.
4. If the respiratory flow rate is large negative and steady then the phase is
0.75 revolutions.
. If the respiratory flow rate is zero and steady and the 5-second low-pass
filtered absolute value of the respiratory flow rate is large then the phase is 0.9
revolutions.
6. If the respiratory flow rate is positive and the phase is expiratory, then the
phase is 0 revolutions.
7. If the respiratory flow rate is negative and the phase is atory, then the
phase is 0.5 revolutions.
8. If the 5-second low-pass filtered absolute value of the atory flow rate
is large, the phase is sing at a steady rate equal to the patient’s breathing
rate, low-pass filtered with a time constant of 20 seconds.
The output of each rule may be represented as a vector whose phase is the
result of the rule and whose magnitude is the fuzzy extent to which the rule is true.
The fuzzy extent to which the respiratory flow rate is “large”, “steady”, etc. is
determined with le membership functions. The results of the rules, represented
as vectors, are then combined by some function such as taking the centroid. In such a
combination, the rules may be equally weighted, or differently weighted.
In another implementation of continuous phase determination, the
tion time Ti and the exhalation time Te are first estimated from the respiratory
flow rate Qr. The phase is then ined as the half the proportion of the
inhalation time Ti that has elapsed since the previous trigger instant, or 0.5 revolutions
plus half the proportion of the exhalation time Te that has elapsed since the previous
cycle instant ever was more recent).
.5.3.2.2 Waveform determination
In one form of the present technology, the therapy parameter
determination thm 4329 provides an approximately constant treatment pressure
throughout a respiratory cycle of a t.
In other forms of the present technology, the therapy parameter
determination algorithm 4329 controls the pressure generator 4140 to provide a
treatment pressure Pt that varies throughout a respiratory cycle of a patient according
to a waveform template.
In one form of the present technology, a waveform determination
algorithm 4322 es a waveform template () with values in the range [0, 1] on
the domain of phase values provided by the phase determination algorithm 4321 to
be used by the therapy parameter determination algorithm 4329.
In one form, suitable for either discrete or continuously-valued phase, the
waveform te () is a square-wave template, having a value of 1 for values of
phase up to and including 0.5 revolutions, and a value of 0 for values of phase above
0.5 revolutions. In one form, suitable for uously-valued phase, the waveform
te () comprises two smoothly curved portions, namely a ly curved
(e.g. raised cosine) rise from 0 to 1 for values of phase up to 0.5 tions, and a
smoothly curved (e.g. exponential) decay from 1 to 0 for values of phase above 0.5
revolutions. In one form, suitable for continuously-valued phase, the waveform
template () is based on a square wave, but with a smooth rise from 0 to 1 for
values of phase up to a “rise time” that is ntially less than 0.5 revolutions, and a
smooth fall from 1 to 0 for values of phase within a “fall time” after 0.5 revolutions.
In some forms of the present technology, the waveform ination
algorithm 4322 selects a waveform template () from a library of waveform
templates, dependent on a setting of the RPT device. Each rm template ()
in the library may be provided as a lookup table of values against phase values .
In other forms, the waveform determination algorithm 4322 computes a waveform
template () “on the fly” using a predetermined functional form, possibly
parametrised by one or more parameters (e,g. time constant of an exponentially
curved portion). The parameters of the functional form may be predetermined or
dependent on a current state of the patient 1000.
In some forms of the present technology, suitable for discrete ued
phase of either inhalation ( = 0 tions) or exhalation ( = 0.5 revolutions), the
waveform determination algorithm 4322 computes a waveform template “on the
fly” as a function of both discrete phase and time t measured since the most recent
trigger instant. In one such form, the waveform determination algorithm 4322
computes the waveform te (, t) in two portions (inspiratory and expiratory)
as follows:
( )t , = 0
( , t ) = i
e (t −Ti ), = 0.5
where i(t) and e(t) are inspiratory and expiratory portions of the
waveform template (, t). In one such form, the inspiratory portion i(t) of the
waveform template is a smooth rise from 0 to 1 parametrised by a rise time, and the
expiratory n e(t) of the waveform template is a smooth fall from 1 to 0
parametrised by a fall time.
.5.3.2.3 ation determination
In one form of the present technology, a ventilation determination
algorithm 4323 receives an input a respiratory flow rate Qr, and determines a measure
indicative of current patient ventilation, Vent.
In some implementations, the ventilation determination algorithm 4323
determines a measure of ventilation Vent that is an te of actual patient
ventilation. One such entation is to take half the absolute value of respiratory
flow rate, Qr, optionally filtered by low-pass filter such as a second order Bessel lowpass
filter with a corner ncy of 0.11 Hz.
In other entations, the ventilation determination algorithm 4323
determines a measure of ation Vent that is broadly proportional to actual patient
ventilation. One such implementation estimates peak respiratory flow rate Qpeak
over the inspiratory portion of the cycle. This and many other procedures involving
sampling the respiratory flow rate Qr produce measures which are broadly
proportional to ventilation, provided the flow rate waveform shape does not vary very
much (here, the shape of two breaths is taken to be similar when the flow rate
waveforms of the s normalised in time and amplitude are similar). Some simple
examples include the median positive respiratory flow rate, the median of the absolute
value of respiratory flow rate, and the standard deviation of flow rate. Arbitrary linear
combinations of arbitrary order statistics of the absolute value of respiratory flow rate
using positive coefficients, and even some using both positive and ve
coefficients, are approximately proportional to ventilation. Another example is the
mean of the respiratory flow rate in the middle K proportion (by time) of the
inspiratory portion, where 0 < K < 1. There is an arily large number of measures
that are exactly proportional to ventilation if the flow rate shape is constant.
.5.3.2.4 Determination of Inspiratory Flow limitation
In one form of the t technology, the central controller 4230 executes
an inspiratory flow limitation determination algorithm 4324 for the determination of
the extent of inspiratory flow limitation.
In one form, the inspiratory flow limitation determination algorithm 4324
receives as an input a atory flow rate signal Qr and provides as an output a
metric of the extent to which the inspiratory portion of the breath exhibits inspiratory
flow tion.
In one form of the present logy, the inspiratory portion of each
breath is identified by a zero-crossing detector. A number of evenly spaced points (for
example, sixty-five), representing points in time, are interpolated by an olator
along the inspiratory flow rate-time curve for each breath. The curve described by the
points is then scaled by a scaler to have unity length (duration/period) and unity area
to remove the effects of changing breathing rate and depth. The scaled breaths are
then ed in a comparator with a pre-stored template representing a normal
unobstructed breath, similar to the inspiratory portion of the breath shown in Fig. 6A.
Breaths deviating by more than a specified threshold (typically 1 scaled unit) at any
time during the ation from this template, such as those due to coughs, sighs,
swallows and hiccups, as determined by a test element, are rejected. For non-rejected
data, a moving e of the first such scaled point is calculated by the central
controller 4230 for the preceding several atory events. This is repeated over the
same inspiratory events for the second such point, and so on. Thus, for example, sixty
five scaled data points are generated by the central controller 4230, and represent a
moving average of the preceding several inspiratory events, e.g., three events. The
moving average of continuously updated values of the (e.g., sixty five) points are
hereinafter called the d flow rate ", ated as Qs(t). Alternatively, a single
inspiratory event can be utilised rather than a moving average.
From the scaled flow rate, two shape factors relating to the determination
of partial obstruction may be calculated.
Shape factor 1 is the ratio of the mean of the middle (e.g. thirty-two)
scaled flow rate points to the mean overall (e.g. sixty-five) scaled flow rate points.
Where this ratio is in excess of unity, the breath will be taken to be normal. Where the
ratio is unity or less, the breath will be taken to be obstructed. A ratio of about 1.17 is
taken as a threshold between partially obstructed and unobstructed breathing, and
equates to a degree of obstruction that would permit maintenance of adequate
oxygenation in a typical patient.
Shape factor 2 is calculated as the RMS deviation from unit scaled flow
rate, taken over the middle (e.g. thirty two) points. An RMS deviation of about 0.2
units is taken to be normal. An RMS deviation of zero is taken to be a totally flow–
limited breath. The closer the RMS deviation to zero, the breath will be taken to be
more flow limited.
Shape factors 1 and 2 may be used as alternatives, or in combination. In
other forms of the t technology, the number of d points, breaths and
middle points may differ from those described above. Furthermore, the threshold
values can other than those described.
.5.3.2.5 Determination of apneas and hypopneas
In one form of the present technology, the central controller 4230 executes
an apnea / hypopnea ination algorithm 4325 for the determination of the
presence of apneas and/or hypopneas.
The apnea / hypopnea determination thm 4325 receives as an input a
respiratory flow rate signal Qr and provide as an output a flag that indicates that an
apnea or a hypopnea has been detected.
In one form, an apnea will be said to have been detected when a function
of respiratory flow rate Qr falls below a flow rate threshold for a predetermined
period of time. The function may determine a peak flow rate, a relatively short-term
mean flow rate, or a flow rate ediate of vely short-term mean and peak
flow rate, for example an RMS flow rate. The flow rate threshold may be a relatively
long-term measure of flow rate.
In one form, a hypopnea will be said to have been detected when a
on of atory flow rate Qr falls below a second flow rate threshold for a
predetermined period of time. The function may determine a peak flow, a relatively
short-term mean flow rate, or a flow rate intermediate of relatively short-term mean
and peak flow rate, for example an RMS flow rate. The second flow rate threshold
may be a relatively long-term measure of flow rate. The second flow rate threshold is
greater than the flow rate threshold used to detect apneas.
.5.3.2.6 Determination of snore
In one form of the present logy, the central controller 4230 executes
one or more snore determination algorithms 4326 for the ination of the extent
of snore.
In one form, the snore determination algorithm 4326 es as an input a
respiratory flow rate signal Qr and provides as an output a metric of the extent to
which snoring is present.
The snore determination thm 4326 may comprise the step of
determining the intensity of the flow rate signal in the range of 30-300 Hz. Further the
snore determination algorithm 4326 may comprise a step of filtering the respiratory
flow rate signal Qr to reduce background noise, e.g., the sound of airflow in the
system from the blower.
.5.3.2.7 Determination of airway patency
In one form of the present technology, the l controller 4230 executes
one or more airway patency determination algorithms 4327 for the determination of
the extent of airway patency.
In one form, the airway patency determination algorithm 4327 receives as
an input a respiratory flow rate signal Qr, and determines the power of the signal in
the frequency range of about 0.75 Hz and about 3 Hz. The presence of a peak in this
ncy range is taken to indicate an open airway. The absence of a peak is taken to
be an indication of a closed airway.
In one form, the frequency range within which the peak is sought is the
frequency of a small forced oscillation in the treatment pressure Pt. In one
implementation, the forced oscillation is of frequency 2 Hz with amplitude about 1
cmH2O.
In one form, airway y determination algorithm 4327 receives as an
input a respiratory flow rate signal Qr, and determines the presence or absence of a
cardiogenic signal. The absence of a cardiogenic signal is taken to be an tion of
a closed airway.
.5.3.2.8 Determination of target ventilation
In one form of the present logy, the central ller 4230 takes as
input the measure of current ventilation, Vent, and executes one or more a target
ventilation determination algorithms 4328 for the determination of a target value Vtgt
for the measure of ation.
In some forms of the present technology, there is no target ventilation
determination thm 4328, and the target value Vtgt is predetermined, for example
by hard-coding during configuration of the RPT device 4000 or by manual entry
through the input device 4220.
In other forms of the present technology, such as adaptive servoventilation
(ASV), the target ation determination algorithm 4328 computes a
target value Vtgt from a value Vtyp indicative of the typical recent ventilation of the
patient.
In some forms of adaptive servo-ventilation, the target ventilation Vtgt is
computed as a high proportion of, but less than, the typical recent ventilation Vtyp.
The high proportion in such forms may be in the range (80%, 100%), or (85%, 95%),
or (87%, 92%).
In other forms of adaptive servo-ventilation, the target ventilation Vtgt is
computed as a slightly greater than unity multiple of the typical recent ventilation
Vtyp.
The typical recent ventilation Vtyp is the value around which the
distribution of the measure of current ventilation Vent over multiple time instants over
some predetermined timescale tends to r, that is, a measure of the central
tendency of the measure of current ventilation over recent history. In one
implementation of the target ation determination algorithm 4328, the recent
history is of the order of several minutes, but in any case should be longer than the
timescale of Cheyne-Stokes waxing and waning cycles. The target ation
determination algorithm 4328 may use any of the y of well-known measures of
central tendency to determine the typical recent ventilation Vtyp from the measure of
current ventilation, Vent. One such measure is the output of a low -pass filter on the
measure of current ventilation Vent, with time constant equal to one hundred seconds.
.5.3.2.9 Determination of therapy parameters
In some forms of the present technology, the l controller 4230
executes one or more therapy parameter determination algorithms 4329 for the
determination of one or more therapy parameters using the values returned by one or
more of the other algorithms in the therapy engine module 4320.
In one form of the present technology, the therapy parameter is an
instantaneous treatment pressure Pt. In one implementation of this form, the therapy
ter determination algorithm 4329 determines the treatment re Pt using
the equation
Pt = A ( ,t ) + P0 (1)
where:
• A is the amplitude,
• ( t) is the rm te value (in the range 0 to 1) at the current
value of phase and t of time, and
• P0 is a base pressure.
If the waveform determination algorithm 4322 provides the waveform
template ( t) as a lookup table of values indexed by phase , the therapy
ter determination thm 4329 applies equation (1) by locating the nearest
lookup table entry to the current value of phase ed by the phase determination
thm 4321, or by interpolation between the two entries straddling the current
value of phase.
The values of the amplitude A and the base pressure P0 may be set by the
therapy parameter determination algorithm 4329 depending on the chosen respiratory
pressure therapy mode in the manner described below.
.5.3.3 Therapy Control module
Therapy control module 4330 in accordance with one aspect of the present
technology receives as inputs the therapy parameters from the therapy parameter
determination algorithm 4329 of the therapy engine module 4320, and controls the
pressure generator 4140 to deliver a flow of air in accordance with the therapy
parameters.
In one form of the present technology, the therapy parameter is a
treatment pressure Pt, and the therapy control module 4330 controls the pressure
generator 4140 to deliver a flow of air whose mask pressure Pm at the patient
interface 3000 is equal to the treatment re Pt.
.5.3.4 Detection of fault conditions
In one form of the present technology, the l ller 4230 executes
one or more methods for the detection of fault conditions 4340. The fault ions
detected by the one or more methods may include at least one of the following:
• Power failure (no power, or insufficient power)
• Transducer fault detection
• Failure to detect the presence of a component
• Operating parameters outside recommended ranges (e.g. pressure, flow rate,
temperature, PaO2)
• Failure of a test alarm to generate a detectable alarm signal.
Upon detection of the fault ion, the corresponding algorithm signals
the presence of the fault by one or more of the following:
• tion of an audible, visual &/or kinetic (e.g. vibrating) alarm
• Sending a message to an external device
• g of the incident
.6 HUMIDIFIER
.6.1 Humidifier overview
In one form of the present technology there is provided a humidifier 5000
(e.g. as shown in Fig. 5A) to change the absolute ty of air or gas for delivery to
a patient relative to t air. Typically, the humidifier 5000 is used to increase the
absolute humidity and increase the temperature of the flow of air (relative to ambient
air) before delivery to the patient’s airways.
The humidifier 5000 may comprise a humidifier reservoir 5110, a
humidifier inlet 5002 to receive a flow of air, and a humidifier outlet 5004 to deliver a
humidified flow of air. In some forms, as shown in Fig. 5A and Fig. 5B, an inlet and
an outlet of the humidifier reservoir 5110 may be the humidifier inlet 5002 and the
humidifier outlet 5004 respectively. The fier 5000 may further comprise a
humidifier base 5006, which may be adapted to receive the humidifier reservoir 5110
and comprise a heating element 5240.
.6.2 Humidifier mechanical ents
.6.2.1 Water reservoir
According to one arrangement, the humidifier 5000 may comprise a water
reservoir 5110 configured to hold, or retain, a volume of liquid (e.g. water) to be
ated for humidification of the flow of air. The water reservoir 5110 may be
configured to hold a predetermined maximum volume of water in order to provide
adequate fication for at least the duration of a respiratory therapy session, such
as one evening of sleep. Typically, the reservoir 5110 is configured to hold several
hundred millilitres of water, e.g. 300 itres (ml), 325 ml, 350 ml or 400 ml. In
other forms, the humidifier 5000 may be configured to receive a supply of water from
an external water source such as a building’s water supply system.
According to one aspect, the water reservoir 5110 is configured to add
ty to a flow of air from the RPT device 4000 as the flow of air travels
hrough. In one form, the water reservoir 5110 may be configured to encourage
the flow of air to travel in a tortuous path h the reservoir 5110 while in contact
with the volume of water therein.
According to one form, the reservoir 5110 may be removable from the
humidifier 5000, for example in a lateral direction as shown in Fig. 5A and Fig. 5B.
The reservoir 5110 may also be configured to discourage egress of liquid
therefrom, such as when the reservoir 5110 is displaced and/or d from its
normal, working orientation, such as through any apertures and/or in between its subcomponents.
As the flow of air to be humidified by the humidifier 5000 is typically
pressurised, the reservoir 5110 may also be configured to prevent losses in pneumatic
pressure through leak and/or flow impedance.
2 Conductive portion
According to one ement, the reservoir 5110 comprises a tive
portion 5120 ured to allow efficient transfer of heat from the g element
5240 to the volume of liquid in the reservoir 5110. In one form, the conductive
portion 5120 may be ed as a plate, although other shapes may also be suitable.
All or a part of the conductive portion 5120 may be made of a thermally conductive
material such as aluminium (e.g. approximately 2 mm thick, such as 1 mm, 1.5 mm,
2.5 mm or 3 mm), another heat conducting metal or some plastics. In some cases,
suitable heat conductivity may be achieved with less conductive materials of suitable
geometry.
.6.2.3 Humidifier reservoir dock
In one form, the humidifier 5000 may comprise a humidifier reservoir
dock 5130 (as shown in Fig. 5B) configured to receive the humidifier reservoir 5110.
In some arrangements, the humidifier reservoir dock 5130 may comprise a locking
feature such as a locking lever 5135 configured to retain the reservoir 5110 in the
humidifier reservoir dock 5130.
.6.2.4 Water level indicator
The humidifier reservoir 5110 may comprise a water level indicator 5150
as shown in Fig. 5A-5B. In some forms, the water level indicator 5150 may e
one or more indications to a user such as the patient 1000 or a care giver regarding a
quantity of the volume of water in the humidifier reservoir 5110. The one or more
indications ed by the water level indicator 5150 may include an tion of a
maximum, predetermined volume of water, any portions thereof, such as 25%, 50% or
75% or volumes such as 200 ml, 300 ml or 400ml.
.6.3 Humidifier Electrical & thermal ents
The humidifier 5000 may comprise a number of electrical and/or thermal
components such as those listed below.
.6.3.1 Humidifier transducer(s)
The humidifier 5000 may comprise one or more humidifier transducers
(sensors) 5210 instead of, or in addition to, transducers 4270 described above.
Humidifier transducers 5210 may include one or more of an air pressure sensor 5212,
an air flow rate transducer 5214, a temperature sensor 5216, or a humidity sensor
5218 as shown in Fig. 5C. A humidifier transducer 5210 may produce one or more
output signals which may be communicated to a controller such as the central
controller 4230 and/or the humidifier ller 5250. In some forms, a humidifier
ucer may be d externally to the humidifier 5000 (such as in the air circuit
4170) while communicating the output signal to the controller.
.6.3.1.1 Pressure transducer
One or more pressure transducers 5212 may be provided to the humidifier
5000 in addition to, or instead of, a pressure sensor provided in the RPT device 4000.
1.2 Flow rate transducer
One or more flow rate transducers 5214 may be provided to the fier
5000 in addition to, or d of, a flow rate sensor provided in the RPT device 4000.
.6.3.1.3 Temperature transducer
The humidifier 5000 may comprise one or more ature transducers
5216. The one or more temperature transducers 5216 may be configured to measure
one or more temperatures such as of the heating element 5240 and/or of the flow of
air downstream of the humidifier outlet 5004. In some forms, the humidifier 5000
may further se a temperature sensor 5216 to detect the temperature of the
ambient air.
1.4 Humidity transducer
In one form, the humidifier 5000 may comprise one or more humidity
sensors 5218 to detect a humidity of a gas, such as the ambient air. The humidity
sensor 5218 may be placed towards the humidifier outlet 5004 in some forms to
measure a humidity of the gas delivered from the humidifier 5000. The humidity
sensor may be an absolute humidity sensor or a relative humidity sensor.
.6.3.2 Heating element
A heating element 5240 may be provided to the humidifier 5000 in some
cases to provide a heat input to one or more of the volume of water in the humidifier
reservoir 5110 and/or to the flow of air. The heating element 5240 may comprise a
heat generating component such as an electrically resistive heating track. One suitable
example of a heating element 5240 is a layered heating element such as one described
in the PCT Patent Application Publication No.
incorporated herewith by nce in its entirety.
In some forms, the heating element 5240 may be provided in the
humidifier base 5006 where heat may be provided to the fier reservoir 5110
primarily by conduction as shown in Fig. 5B.
.6.3.3 Humidifier controller
According to one ement of the present technology, a humidifier
5000 may comprise a humidifier controller 5250 as shown in Fig. 5C. In one form, the
humidifier controller 5250 may be a part of the central controller 4230. In r
form, the humidifier ller 5250 may be a separate controller, which may be in
ication with the central controller 4230.
In one form, the humidifier ller 5250 may receive as inputs
measures of characteristics (such as temperature, humidity, pressure and/or flow rate),
for example of the flow of air, the water in the reservoir 5110 and/or the humidifier
5000. The humidifier controller 5250 may also be configured to execute or implement
humidifier algorithms and/or deliver one or more output signals.
As shown in Fig. 5C, the humidifier controller 5250 may comprise one or
more controllers, such as a central humidifier controller 5251, a heated air circuit
controller 5254 configured to control the ature of a heated air circuit 4170
and/or a heating element controller 5252 configured to control the temperature of a
heating element 5240.
.7 RESPIRATORY PRESSURE THERAPY MODES
s respiratory pressure therapy modes may be implemented by the
RPT device 4000 depending on the values of the ters A and P0 in the treatment
pressure equation (1) used by the therapy parameter determination algorithm 4329 in
one form of the present technology.
.7.1 CPAP therapy
In some implementations of this form of the present technology, the
amplitude A is identically zero, so the treatment pressure Pt is identically equal to the
base pressure P0 throughout the respiratory cycle. Such entations are
generally grouped under the heading of CPAP therapy. In such implementations,
there is no need for the therapy engine module 4320 to determine phase or the
waveform template ().
In CPAP therapy modes, the base pressure P0 may be a constant value that
is hard-coded or manually entered to the RPT device 4000. This ative is
mes referred to as constant CPAP therapy. The constant value for the base
pressure P0 may be selected for a given patient via a process known as titration.
During titration, a clinician typically adjusts the treatment pressure Pt in response to
observations of flow limitation, apnea, hypopnea, patency, and snore during a titration
session. The titrated base pressure P0 may be then computed as a tical summary
of the ent re Pt during the titration session.
Alternatively, the therapy parameter determination algorithm 4329 may
continuously compute the base pressure P0 during CPAP therapy. In this ative,
the therapy parameter determination algorithm 4329 continuously computes the base
pressure P0 as a function of s or measures of sleep disordered breathing returned
by the respective thms in the therapy engine module 4320, such as one or more
of flow limitation, apnea, ea, patency, and snore. This alternative is
mes referred to as APAP therapy. Because the continuous computation of the
base pressure P0 resembles the manual adjustment of the treatment pressure Pt by a
clinician during titration, APAP therapy is also sometimes referred to as itrating
CPAP.
.7.2 Bi-level therapy
In other implementations of this form of the present technology, the value
of amplitude A in equation (1) may be positive. Such implementations are known as
bi-level therapy, because in determining the treatment pressure Pt using equation (1)
with positive amplitude A, the y parameter determination algorithm 4329
oscillates the treatment pressure Pt between two values or levels in synchrony with
the spontaneous atory effort of the patient 1000. That is, based on the typical
waveform templates ( t) described above, the therapy parameter determination
algorithm 4329 increases the treatment pressure Pt to P0 + A (known as the IPAP) at
the start of, or , or inspiration and decreases the treatment pressure Pt to the
base pressure P0 (known as the EPAP) at the start of, or during, expiration.
In some forms of bi-level therapy, the IPAP is a prescribed treatment
pressure that has the same purpose as the treatment pressure in CPAP therapy modes,
and the EPAP is the IPAP minus the amplitude A, which has a ” value (a few
cmH2O) sometimes referred to as the Expiratory Pressure Relief (EPR). Such forms
are sometimes referred to as CPAP therapy with EPR, which is generally thought to
be more table than straight CPAP therapy. In CPAP therapy with EPR, either
or both of the IPAP and the EPAP may be constant values that are hard-coded or
manually entered to the RPT device 4000. Alternatively, the therapy parameter
determination algorithm 4329 may continuously compute the IPAP and / or the EPAP
during CPAP with EPR. In this alt ernative, the therapy parameter determination
algorithm 4329 continuously es the EPAP and / or the IPAP as a function of
indices or measures of sleep disordered breathing returned by the respective
algorithms in the therapy engine module 4320 is analogous fashion to the computation
of the base re P0 in APAP y bed above.
In other forms of bi-level therapy, the amplitude A is large enough that the
RPT device 4000 does some or all of the work of breathing of the patient 1000. In
such forms, known as pressure support ventilation therapy, the amplitude A is referred
to as the pressure support, or swing. In pressure support ventilation therapy, the IPAP
is the base pressure P0 plus the pressure support A, and the EPAP is the base re
In some forms of pressure support ventilation therapy, known as fixed
pressure support ventilation y, the pressure support A is fixed at a
predetermined value, e.g. 10 cmH2O. The predetermined pressure support value is a
setting of the RPT device 4000, and may be set for example by hard-coding during
configuration of the RPT device 4000 or by manual entry through the input device
4220.
In some forms of pressure support ventilation y, known as servoventilation
, the therapy parameter determination algorithm 4329 takes as input the
t measure Vent of ventilation and the target value Vtgt of ventilation provided
by the target ventilation determination algorithm 4328 and continuously s the
parameters of on (1) to bring the current measure Vent of ventilation towards
the target value Vtgt of ventilation. In a form of servo-ventilation known as adaptive
ventilation (ASV), which has been used to treat CSR, the target ventilation Vtgt
is computed by the target ventilation determination algorithm 4328 from the typical
recent ventilation Vtyp, as described above.
In some forms of servo-ventilation, the therapy parameter determination
algorithm 4329 applies a control methodology to continuously compute the pressure
support A so as to bring the current measure Vent of ventilation towards the target
ventilation Vtgt. One such control methodology is Proportional -Integral (PI) control.
In one implementation of PI control, suitable for ASV modes in which a target
ventilation Vtgt is set to slightly less than the typical recent ventilation Vtyp, the
pressure support is computed as:
A = G(Vent −Vtgt)dt
where G is the gain of the PI control. Larger values of gain G can result
in positive feedback in the y engine module 4320. Smaller values of gain G
may permit some residual untreated CSR or central sleep apnea. In some
implementations, the gain G is fixed at a predetermined value, such
as -0.4 cmH2O/(L/min)/sec. Alternatively, the gain G may be varied between therapy
sessions, starting small and increasing from session to session until a value that all but
eliminates CSR is reached. Conventional means for pectively analysing the
parameters of a y n to assess the ty of CSR during the therapy
n may be employed in such implementations. In yet other implementations, the
gain G may vary depending on the difference between the current measure Vent of
ventilation and the target ventilation Vtgt.
Other servo-ventilation control methodologies that may be applied by the
therapy parameter determination algorithm 4329 include proportional (P),
tional-differential (PD), and proportional-integral-differential (PID).
The value of the pressure support A computed via equation (2) may be
clipped to a range d as [Amin, Amax]. In this implementation, the pressure
support A sits by default at the minimum pressure support Amin until the measure of
current ventilation Vent falls below the target ventilation Vtgt, at which point A starts
sing, only falling back to Amin when Vent exceeds Vtgt once again.
The pressure support limits Amin and Amax are settings of the RPT device
4000, set for example by hard-coding during configuration of the RPT device 4000 or
by manual entry through the input device 4220. A m pressure support Amin
of 3 cmH2O is of the order of 50% of the pressure support required to perform all the
work of breathing of a l patient in the steady state. A maximum pressure
support Amax of 12 cmH2O is approximately double the pressure support required to
perform all the work of breathing of a l patient, and therefore sufficient to
support the patient’s breathing if they cease making any s, but less than a value
that would be uncomfortable or dangerous.
In pressure support ventilation therapy modes, the EPAP is the base
pressure P0. As with the base pressure P0 in CPAP therapy, the EPAP may be a
constant value that is ibed or determined during titration. Such a constant EPAP
may be set for example by hard-coding during configuration of the RPT device 4000
or by manual entry through the input device 4220. This alternative is sometimes
referred to as fixed-EPAP pressure support ventilation therapy. Titration of the EPAP
for a given patient may be med by a clinician during a titration session with the
aid of PSG, with the aim of preventing obstructive apneas, thereby maintaining an
open airway for the re support ventilation therapy, in similar fashion to titration
of the base pressure P0 in constant CPAP y.
Alternatively, the therapy parameter ination algorithm 4329 may
continuously e the base pressure P0 during pressure support ventilation
therapy. In such implementations, the therapy parameter determination algorithm
4329 continuously computes the EPAP as a function of indices or measures of sleep
disordered ing ed by the respective algorithms in the therapy engine
module 4320, such as one or more of flow limitation, apnea, hypopnea, patency, and
snore. Because the continuous computation of the EPAP resembles the manual
adjustment of the EPAP by a clinician during ion of the EPAP, this process is
also sometimes referred to as auto-titration of the EPAP, and the overall therapy is
known as auto-titrating EPAP pressure support ventilation therapy, or auto-EPAP
pressure support ventilation therapy.
.8 GLOSSARY
For the purposes of the present technology disclosure, in certain forms of
the present technology, one or more of the ing definitions may apply. In other
forms of the present technology, alternative definitions may apply.
.8.1 General
Air: In certain forms of the present technology, air may be taken to mean
atmospheric air, and in other forms of the present technology air may be taken to
mean some other ation of breathable gases, e.g. atmospheric air enriched with
oxygen.
Ambient: In certain forms of the present logy, the term ambient will
be taken to mean (i) external of the treatment system or patient, and (ii) immediately
surrounding the treatment system or patient.
For example, t humidity with respect to a humidifier may be the
humidity of air immediately surrounding the humidifier, e.g. the humidity in the room
where a patient is sleeping. Such ambient humidity may be different to the ty
outside the room where a patient is sleeping.
In r example, t pressure may be the pressure immediately
surrounding or external to the body.
In certain forms, ambient (e.g., acoustic) noise may be considered to be
the background noise level in the room where a patient is located, other than for
example, noise generated by an RPT device or emanating from a mask or patient
interface. Ambient noise may be generated by s outside the room.
Respiratory Pressure Therapy (RPT): The application of a supply of air to
an entrance to the airways at a treatment pressure that is typically positive with
respect to atmosphere.
Continuous Positive Airway Pressure (CPAP) therapy: Respiratory
pressure therapy in which the treatment pressure is approximately constant through a
respiratory cycle of a t. In some forms, the pressure at the entrance to the
s will be slightly higher during exhalation, and slightly lower during inhalation.
In some forms, the pressure will vary between ent respiratory cycles of the
t, for e, being increased in response to detection of indications of partial
upper airway obstruction, and decreased in the absence of indications of partial upper
airway obstruction.
Patient: A person, whether or not they are suffering from a respiratory
disease.
Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in
which the treatment pressure is automatically adjustable, e.g. from breath to breath,
between minimum and maximum limits, depending on the ce or absence of
indications of SDB events.
.8.2 Aspects of the respiratory cycle
Apnea: According to some tions, an apnea is said to have occurred
when flow falls below a predetermined threshold for a duration, e.g. 10 seconds. An
obstructive apnea will be said to have ed when, despite t effort, some
obstruction of the airway does not allow air to flow. A l apnea will be said to
have occurred when an apnea is detected that is due to a reduction in breathing effort,
or the absence of breathing effort, despite the airway being patent. A mixed apnea
occurs when a reduction or e of breathing effort coincides with an obstructed
airway.
Breathing rate: The rate of spontaneous respiration of a patient, usually
measured in breaths per minute.
Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.
Effort (breathing): Breathing effort will be said to be the work done by a
spontaneously breathing person attempting to e.
Expiratory portion of a breathing cycle: The period from the start of
expiratory flow to the start of inspiratory flow.
Flow tion: Flow limitation will be taken to be the state of affairs in a
patient's respiration where an increase in effort by the patient does not give rise to a
corresponding increase in flow. Where flow limitation occurs during an inspiratory
portion of the breathing cycle it may be described as inspiratory flow tion.
Where flow tion occurs during an expiratory portion of the breathing cycle it
may be described as expiratory flow tion.
Types of flow limited inspiratory waveforms:
(i) Flattened: Having a rise followed by a vely flat portion, followed
by a fall.
(ii) M-shaped: Having two local peaks, one at the leading edge, and one at
the trailing edge, and a relatively flat portion between the two peaks.
(iii) Chair-shaped: Having a single local peak, the peak being at the
leading edge, followed by a relatively flat portion.
(iv) Reverse-chair shaped: Having a relatively flat n followed by
single local peak, the peak being at the trailing edge.
Hypopnea: ably, a hypopnea will be taken to be a reduction in flow,
but not a cessation of flow. In one form, a hypopnea may be said to have occurred
when there is a reduction in flow below a threshold rate for a duration. A central
hypopnea will be said to have occurred when a hypopnea is detected that is due to a
reduction in breathing effort. In one form in adults, either of the following may be
regarded as being hypopneas:
(i) a 30% reduction in patient breathing for at least 10 seconds plus an
associated 4% desaturation; or
(ii) a ion in patient breathing (but less than 50%) for at least 10 seconds,
with an associated desaturation of at least 3% or an l.
Hyperpnea: An increase in flow to a level higher than normal flow rate.
Inspiratory portion of a breathing cycle: The period from the start of
inspiratory flow to the start of tory flow will be taken to be the inspiratory
portion of a breathing cycle.
Patency (airway): The degree of the airway being open, or the extent to
which the airway is open. A patent airway is open. Airway patency may be
quantified, for example with a value of one (1) being patent, and a value of zero (0),
being closed (obstructed).
Positive End-Expiratory Pressure (PEEP): The pressure above
atmosphere in the lungs that exists at the end of expiration.
Peak flow rate (Qpeak): The maximum value of flow rate during the
atory portion of the respiratory flow waveform.
Respiratory flow rate, w rate, patient airflow rate, respiratory
airflow rate (Qr): These synonymous terms may be understood to refer to the RPT
device’s estimate of respiratory airflow rate, as d to “true respiratory flow” or
“true respiratory airflow”, which is the actual respiratory flow rate experienced by the
patient, usually expressed in litres per minute.
Tidal volume (Vt): The volume of air inhaled or exhaled during normal
breathing, when extra effort is not applied.
(inhalation) Time (Ti): The duration of the inspiratory portion of the
respiratory flow rate waveform.
(exhalation) Time (Te): The duration of the expiratory portion of the
respiratory flow rate waveform.
) Time (Ttot): The total on between the start of the inspiratory
portion of one respiratory flow rate waveform and the start of the inspiratory portion
of the following respiratory flow rate waveform.
Typical recent ventilation: The value of ventilation around which recent
values over some predetermined ale tend to cluster, that is, a measure of the
central tendency of the recent values of ventilation.
Upper airway obstruction (UAO): includes both partial and total upper
airway obstruction. This may be associated with a state of flow limitation, in which
the level of flow increases only slightly or may even decrease as the pressure
difference across the upper airway increases (Starling resistor behaviour).
Ventilation : A measure of the total amount of gas being exchanged
by the patient’s respiratory system. Measures of ventilation may include one or both
of inspiratory and expiratory flow, per unit time. When expressed as a volume per
minute, this quantity is often referred to as “minute ventilation”. Minute ventilation is
sometimes given simply as a , understood to be the volume per minute.
.8.3 RPT device ters
Flow rate: The instantaneous volume (or mass) of air delivered per unit
time. While flow rate and ventilation have the same ions of volume or mass
per unit time, flow rate is measured over a much r period of time. In some
cases, a reference to flow rate will be a reference to a scalar quantity, namely a
quantity having magnitude only. In other cases, a nce to flow rate will be a
reference to a vector quantity, namely a quantity having both magnitude and direction.
Where it is referred to as a signed quantity, a flow rate may be nominally positive for
the inspiratory portion of a breathing cycle of a t, and hence negative for the
expiratory portion of the breathing cycle of a patient. Flow rate will be given the
symbol Q. ‘Flow rate’ is mes shortened to simply ‘flow’. Total flow rate, Qt, is
the flow rate of air g the RPT device. Vent flow rate, Qv, is the flow rate of air
leaving a vent to allow washout of exhaled gases. Leak flow rate, Ql, is the flow rate
of leak from a patient interface system. Respiratory flow rate, Qr, is the flow rate of
air that is received into the patient's respiratory system.
Leak: The word leak will be taken to be an unintended flow of air. In one
example, leak may occur as the result of an incomplete seal between a mask and a
patient's face. In another example leak may occur in a swivel elbow to the ambient.
Noise, conducted (acoustic): Conducted noise in the present document
refers to noise which is carried to the patient by the pneumatic path, such as the air
circuit and the patient interface as well as the air therein. In one form, conducted noise
may be quantified by measuring sound re levels at the end of an air circuit.
Noise, radiated (acoustic): Radiated noise in the present document refers
to noise which is carried to the patient by the ambient air. In one form, radiated noise
may be fied by measuring sound power/pressure levels of the object in question
according to ISO 3744.
Noise, vent (acoustic): Vent noise in the present document refers to noise
which is generated by the flow of air through any vents such as vent holes in the
patient interface.
Pressure: Force per unit area. re may be measured in a range of
units, including cmH2O, g-f/cm2, hectopascal. 1 cmH2O is equal to 1 2 and is
approximately 0.98 hectopascal. In this specification, unless otherwise stated,
pressure is given in units of cmH2O. The pressure in the patient interface is given the
symbol Pm, while the treatment pressure, which represents a target value to be
achieved by the mask pressure Pm at the current instant of time, is given the symbol
Sound Power: The energy per unit time carried by a sound wave. The
sound power is proportional to the square of sound pressure multiplied by the area of
the wavefront. Sound power is usually given in decibels SWL, that is, decibels
relative to a reference power, ly taken as 10-12 watt.
Sound Pressure: The local ion from ambient pressure at a given
time t as a result of a sound wave travelling through a medium. Sound pressure
is usually given in decibels SPL, that is, decibels relative to a reference pressure,
normally taken as 20 × 10-6 Pascal (Pa), considered the threshold of human hearing.
.8.4 Terms for ventilators
Adaptive Servo-Ventilator (ASV): A servo-ventilator that has a
able, rather than fixed target ventilation. The changeable target ventilation may
be d from some characteristic of the patient, for example, a respiratory
characteristic of the patient.
Backup rate: A parameter of a ventilator that establishes the minimum
breathing rate (typically in number of breaths per minute) that the ventilator will
deliver to the t, if not triggered by spontaneous atory effort.
Cycled: The termination of a ventilator's inspiratory phase. When a
ventilator delivers a breath to a spontaneously breathing patient, at the end of the
inspiratory n of the breathing cycle, the ventilator is said to be cycled to stop
delivering the breath.
Expiratory positive airway re (EPAP): a base pressure, to which a
pressure g within the breath is added to produce the desired mask pressure
which the ventilator will attempt to achieve at a given time.
End expiratory pressure (EEP): Desired mask pressure which the
ventilator will attempt to achieve at the end of the expiratory portion of the breath. If
the pressure waveform template () is zero-valued at the end of expiration, i.e.
() = 0 when = 1, the EEP is equal to the EPAP.
Inspiratory positive airway pressure (IPAP): Maximum desired mask
pressure which the ventilator will attempt to e during the inspiratory portion of
the breath.
Pressure support: A number that is indicative of the increase in re
during ventilator inspiration over that during ator expiration, and generally
means the difference in pressure between the maximum value during inspiration and
the base pressure (e.g., PS = IPAP – EPAP). In some contexts pressure support
means the difference which the ventilator aims to achieve, rather than what it ly
achieves.
Servo-ventilator: A ventilator that measures patient ventilation, has a
target ventilation, and which adjusts the level of pressure support to bring the patient
ventilation s the target ventilation.
Spontaneous/Timed (S/T): A mode of a ventilator or other device that
attempts to detect the initiation of a breath of a neously breathing patient. If
however, the device is unable to detect a breath within a predetermined period of
time, the device will automatically initiate delivery of the .
Swing: Equivalent term to pressure support.
Triggered: When a ventilator delivers a breath of air to a spontaneously
breathing patient, it is said to be triggered to do so at the initiation of the respiratory
portion of the breathing cycle by the patient's efforts.
Typical recent ventilation: The typical recent ventilation Vtyp is the value
around which recent es of ventilation over some predetermined timescale tend
to cluster. For example, a measure of the central tendency of the measures of
ventilation over recent history may be a suitable value of a typical recent ventilation.
Ventilator: A mechanical device that provides re support to a
patient to perform some or all of the work of breathing.
.8.5 Anatomy of the face
Ala: the external outer wall or "wing" of each nostril (plural: alar)
Alare: The most lateral point on the nasal ala.
Alar curvature (or alar crest) point: The most posterior point in the
curved base line of each ala, found in the crease formed by the union of the ala with
the cheek.
Auricle: The whole external visible part of the ear.
(nose) Bony framework: The bony ork of the nose ses the
nasal bones, the frontal process of the maxillae and the nasal part of the frontal bone.
(nose) Cartilaginous framework: The cartilaginous framework of the nose
comprises the septal, l, major and minor cartilages.
Columella: the strip of skin that separates the nares and which runs from
the pronasale to the upper lip.
Columella angle: The angle between the line drawn through the midpoint
of the l aperture and a line drawn perpendicular to the Frankfurt horizontal while
intersecting subnasale.
ort horizontal plane: A line extending from the most inferior point
of the orbital margin to the left tragion. The tragion is the deepest point in the notch
superior to the tragus of the auricle.
Glabella: Located on the soft tissue, the most prominent point in the
midsagittal plane of the forehead.
Lateral nasal cartilage: A generally triangular plate of cartilage. Its
or margin is attached to the nasal bone and l s of the maxilla, and
its inferior margin is connected to the greater alar cartilage.
Greater alar cartilage: A plate of cartilage lying below the l nasal
cartilage. It is curved around the anterior part of the naris. Its posterior end is
connected to the frontal process of the maxilla by a tough fibrous ne
containing three or four minor cartilages of the ala.
Nares (Nostrils): Approximately ellipsoidal apertures forming the
ce to the nasal cavity. The singular form of nares is naris (nostril). The nares are
separated by the nasal septum.
Naso-labial sulcus or Naso-labial fold: The skin fold or groove that runs
from each side of the nose to the corners of the mouth, separating the cheeks from the
upper lip.
Naso-labial angle: The angle between the columella and the upper lip,
while intersecting subnasale.
Otobasion inferior: The lowest point of attachment of the auricle to the
skin of the face.
Otobasion superior: The highest point of attachment of the auricle to the
skin of the face.
Pronasale: the most protruded point or tip of the nose, which can be
identified in lateral view of the rest of the portion of the head.
Philtrum: the midline groove that runs from lower border of the nasal
septum to the top of the lip in the upper lip region.
on: Located on the soft tissue, the most anterior midpoint of the
chin.
Ridge (nasal): The nasal ridge is the e ence of the nose,
extending from the Sellion to the Pronasale.
Sagittal plane: A vertical plane that passes from anterior (front) to
posterior (rear) dividing the body into right and left halves.
Sellion: Located on the soft tissue, the most concave point overlying the
area of the frontonasal .
Septal cartilage (nasal): The nasal septal age forms part of the
septum and divides the front part of the nasal cavity.
Subalare: The point at the lower margin of the alar base, where the alar
base joins with the skin of the superior (upper) lip.
Subnasal point: Located on the soft tissue, the point at which the
columella merges with the upper lip in the midsagittal plane.
Supramentale: The point of greatest concavity in the midline of the lower
lip between labrale us and soft tissue pogonion
.8.6 Anatomy of the skull
Frontal bone: The frontal bone includes a large vertical portion, the
squama frontalis, corresponding to the region known as the forehead.
Mandible: The mandible forms the lower jaw. The mental protuberance is
the bony protuberance of the jaw that forms the chin.
Maxilla: The maxilla forms the upper jaw and is located above the
mandible and below the orbits. The l process of the maxilla projects upwards by
the side of the nose, and forms part of its lateral boundary.
Nasal bones: The nasal bones are two small oblong bones, varying in size
and form in different individuals; they are placed side by side at the middle and upper
part of the face, and form, by their on, the "bridge" of the nose.
: The intersection of the frontal bone and the two nasal bones, a
depressed area directly between the eyes and superior to the bridge of the nose.
Occipital bone: The occipital bone is situated at the back and lower part of
the m. It includes an oval aperture, the foramen , through which the
cranial cavity communicates with the vertebral canal. The curved plate behind the
foramen magnum is the squama occipitalis.
Orbit: The bony cavity in the skull to contain the eyeball.
Parietal bones: The parietal bones are the bones that, when joined
together, form the roof and sides of the cranium.
Temporal bones: The temporal bones are situated on the bases and sides
of the skull, and support that part of the face known as the temple.
Zygomatic bones: The face includes two zygomatic bones, located in the
upper and lateral parts of the face and forming the prominence of the cheek.
.8.7 Anatomy of the respiratory system
Diaphragm: A sheet of muscle that extends across the bottom of the rib
cage. The agm separates the thoracic cavity, containing the heart, lungs and
ribs, from the abdominal cavity. As the agm contracts the volume of the
thoracic cavity increases and air is drawn into the lungs.
Larynx: The larynx, or voice box houses the vocal folds and connects the
inferior part of the pharynx (hypopharynx) with the trachea.
Lungs: The organs of respiration in humans. The conducting zone of the
lungs contains the trachea, the bronchi, the bronchioles, and the terminal bronchioles.
The respiratory zone contains the respiratory bronchioles, the ar ducts, and the
Nasal cavity: The nasal cavity (or nasal fossa) is a large air filled space
above and behind the nose in the middle of the face. The nasal cavity is divided in two
by a vertical fin called the nasal septum. On the sides of the nasal cavity are three
horizontal outgrowths called nasal e (singular "concha") or turbinates. To the
front of the nasal cavity is the nose, while the back blends, via the choanae, into the
arynx.
Pharynx: The part of the throat ed immediately inferior to (below)
the nasal cavity, and superior to the oesophagus and larynx. The pharynx is
conventionally divided into three sections: the nasopharynx arynx) (the nasal
part of the pharynx), the oropharynx (mesopharynx) (the oral part of the pharynx),
and the laryngopharynx (hypopharynx).
.8.8 Materials
Silicone or Silicone Elastomer: A tic rubber. In this specification, a
reference to silicone is a reference to liquid ne rubber (LSR) or a compression
moulded silicone rubber (CMSR). One form of commercially available LSR is
SILASTIC (included in the range of products sold under this trademark),
manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless
otherwise specified to the contrary, an ary form of LSR has a Shore A (or
Type A) indentation hardness in the range of about 35 to about 45 as measured using
ASTM D2240.
Polycarbonate: a typically transparent thermoplastic polymer of
Bisphenol-A Carbonate.
.8.9 Aspects of a patient interface
Anti-asphyxia valve (AAV): The component or sub-assembly of a mask
system that, by opening to atmosphere in a failsafe manner, reduces the risk of
excessive CO2 thing by a patient.
Elbow: A conduit that directs an axis of flow of air to change direction
through an angle. In one form, the angle may be approximately 90 degrees. In another
form, the angle may be less than 90 degrees. The conduit may have an approximately
circular cross-section. In another form the conduit may have an oval or a rectangular
cross-section.
Frame: Frame will be taken to mean a mask structure that bears the load
of tension between two or more points of connection with a headgear. A mask frame
may be a non-airtight load bearing ure in the mask. r, some forms of
mask frame may also be ght.
Headgear: ar will be taken to mean a form of positioning and
stabilizing structure designed for use on a head. Preferably the headgear ses a
collection of one or more struts, ties and ners configured to locate and retain a
patient ace in position on a patient’s face for delivery of respiratory therapy.
Some ties are formed of a soft, flexible, elastic material such as a laminated composite
of foam and fabric.
Membrane: Membrane will be taken to mean a typically thin element that
has, preferably, substantially no resistance to bending, but has resistance to being
stretched.
Plenum chamber: a mask plenum chamber will be taken to mean a portion
of a patient interface having walls at least partially enclosing a volume of space, the
volume having air therein pressurised above atmospheric re in use. A shell may
form part of the walls of a mask plenum chamber.
Seal: The noun form ("a seal") will be taken to mean a structure or barrier
that intentionally resists the flow of air through the interface of two surfaces. The verb
form ("to seal") will be taken to mean to resist a flow of air.
Shell: A shell will be taken to mean a curved, relatively thin structure
having bending, tensile and compressive stiffness. For example, a curved structural
wall of a mask may be a shell. In some forms, a shell may be faceted. In some forms a
shell may be airtight. In some forms a shell may not be airtight.
Stiffener: A stiffener will be taken to mean a ural component
ed to increase the bending resistance of another ent in at least one
direction.
Strut: A strut will be taken to be a structural component designed to
increase the compression resistance of another component in at least one direction.
Swivel: (noun) A subassembly of components configured to rotate about a
common axis, preferably independently, preferably under low torque. In one form, the
swivel may be constructed to rotate h an angle of at least 360 degrees. In
another form, the swivel may be constructed to rotate through an angle less than 360
degrees. When used in the context of an air ry conduit, the sub-assembly of
components preferably comprises a matched pair of cylindrical conduits. There may
be little or no leak flow of air from the swivel in use.
Tie: A tie will be taken to be a structural component designed to resist
tension.
Vent: (noun) the structure that allows a flow of air from an interior of the
mask, or conduit, to ambient air to allow clinically effective washout of d
gases. For example, a clinically effective washout may involve a flow rate of about 10
litres per minute to about 100 litres per minute, ing on the mask design and
treatment re.
.8.10 Terms used in relation to patient interface
Curvature (of a surface): A region of a surface having a saddle shape,
which curves up in one direction and curves down in a different direction, will be said
to have a negative curvature. A region of a surface having a dome shape, which
curves the same way in two principal directions, will be said to have a positive
ure. A flat surface will be taken to have zero curvature.
Floppy: A quality of a material, structure or composite that is one or
more of:
• Readily conforming to finger pressure.
• Unable to retain its shape when caused to support its own weight.
• Not rigid.
• Able to be hed or bent cally with little .
The quality of being floppy may have an associated direction, hence a
particular material, structure or composite may be floppy in a first direction, but stiff
or rigid in a second direction, for e a second direction that is orthogonal to the
first direction.
Resilient: Able to deform substantially cally, and to release
substantially all of the energy upon unloading, within a relatively short period of time
such as 1 second.
Rigid: Not readily deforming to finger pressure, and/or the tensions or
loads typically encountered when setting up and maintaining a patient interface in
sealing relationship with an entrance to a patient's airways.
Semi-rigid: means being sufficiently rigid to not substantially distort
under the effects of mechanical forces typically applied during respiratory pressure
therapy.
.8.11 Curvature
Products in accordance with the present technology may se one or
more real three-dimensional ures, for example a mask cushion or an impeller.
The three-dimensional structures may be bounded by two-dimensional surfaces.
These es may be distinguished using a label to describe an associated surface
orientation, location, function, or some other teristic. For example a structure
may comprise one or more of an anterior surface, a posterior surface, an interior
surface and an exterior surface. In r example, a cushion ure may comprise
a face-contacting (e.g. outer) surface, and a separate non-face-contacting (e.g.
underside or inner) surface. In another example, a structure may comprise a first
surface and a second surface.
To facilitate describing the shape of the three-dimensional structures and
the surfaces, we first consider a cross-section through a surface of the structure at a
point, p. See Fig. 3B to Fig. 3F, which illustrate examples of cross-sections at point p
on a surface, and the resulting plane curves. Figs. 3B to 3F also illustrate an outward
normal vector at p. The outward normal vector at p points away from the surface. In
some examples we describe the surface from the point of view of an imaginary small
person standing upright on the surface.
.8.11.1 Curvature in one dimension
The curvature of a plane curve at p may be described as having a sign
(e.g. positive, negative) and a magnitude (e.g. 1/radius of a circle that just touches the
curve at p).
Positive curvature: If the curve at p turns towards the outward normal, the
curvature at that point will be taken to be positive (if the imaginary small person
leaves the point p they must walk uphill). See Fig. 3B (relatively large positive
curvature compared to Fig. 3C) and Fig. 3C (relatively small positive curvature
compared to Fig. 3B). Such curves are often referred to as concave.
Zero curvature: If the curve at p is a straight line, the curvature will be
taken to be zero (if the imaginary small person leaves the point p, they can walk on a
level, neither up nor down). See Fig. 3D.
Negative ure: If the curve at p turns away from the outward normal,
the curvature in that direction at that point will be taken to be negative (if the
imaginary small person leaves the point p they must walk downhill). See Fig. 3E
(relatively small negative curvature compared to Fig. 3F) and Fig. 3F (relatively large
negative curvature compared to Fig. 3E). Such curves are often referred to as convex.
.2 Curvature of two dimensional es
A description of the shape at a given point on a two-dimensional surface
in ance with the present technology may include multiple normal crosssections.
The multiple cross-sections may cut the e in a plane that includes the
d normal (a l plane”), and each cross-section may be taken in a different
direction. Each cross-section results in a plane curve with a corresponding curvature.
The different curvatures at that point may have the same sign, or a different sign.
Each of the curvatures at that point has a ude, e.g. relatively small. The plane
curves in Figs. 3B to 3F could be examples of such multiple cross-sections at a
particular point.
Principal curvatures and directions: The directions of the normal planes
where the curvature of the curve takes its m and minimum values are called
the pal directions. In the examples of Fig. 3B to Fig. 3F, the m curvature
occurs in Fig. 3B, and the minimum occurs in Fig. 3F, hence Fig. 3B and Fig. 3F are
cross sections in the principal directions. The principal curvatures at p are the
curvatures in the principal directions.
Region of a surface: A set of points on a surface. The set of points in a
region may have similar characteristics, e.g. curvatures or signs.
Saddle : A region where at each point, the principal curvatures have
opposite signs, that is, one is positive, and the other is negative (depending on the
direction to which the imaginary person turns, they may walk uphill or downhill).
Dome region: A region where at each point the principal curvatures have
the same sign, e.g. both positive (a “concave dome”) or both negative (a x
dome”).
Cylindrical region: A region where one principal curvature is zero (or, for
example, zero within manufacturing tolerances) and the other principal curvature is
non-zero.
Planar region: A region of a surface where both of the principal
curvatures are zero (or, for example, zero within manufacturing tolerances).
Edge of a e: A boundary or limit of a surface.
Path: In certain forms of the present technology, ‘path’ will be taken to
mean a path in the mathematical – topological sense, e.g. a continuous space curve
from f(0) to f(1) on a surface. In certain forms of the present technology, a ‘path’ may
be described as a route or course, ing e.g. a set of points on a surface. (The path
for the imaginary person is where they walk on the e, and is ous to a
garden path).
Path length: In certain forms of the present technology, ‘path length’ will
be taken to the distance along the surface from f(0) to f(1), that is, the distance along
the path on the surface. There may be more than one path between two points on a
surface and such paths may have different path lengths. (The path length for the
imaginary person would be the distance they have to walk on the surface along the
path).
Straight-line distance: The straight-line distance is the distance between
two points on a surface, but without regard to the surface. On planar regions, there
would be a path on the surface having the same path length as the straight-line
ce between two points on the surface. On non-planar surfaces, there may be no
paths having the same path length as the straight-line distance between two points.
(For the imaginary person, the straight-line distance would correspond to the distance
‘as the crow flies’.)
.9 OTHER S
A portion of the disclosure of this patent document contains material
which is subject to copyright protection. The copyright owner has no objection to the
facsimile reproduction by anyone of the patent document or the patent disclosure, as it
appears in Patent Office patent files or records, but otherwise es all copyright
rights ever.
Unless the t clearly dictates otherwise and where a range of values
is provided, it is understood that each intervening value, to the tenth of the unit of the
lower limit, between the upper and lower limit of that range, and any other stated or
ening value in that stated range is encompassed within the technology. The
upper and lower limits of these intervening ranges, which may be independently
included in the ening , are also encompassed within the technology,
subject to any specifically excluded limit in the stated range. Where the stated range
includes one or both of the limits, ranges excluding either or both of those included
limits are also included in the technology.
Furthermore, where a value or values are stated herein as being
implemented as part of the technology, it is understood that such values may be
approximated, unless otherwise stated, and such values may be utilized to any suitable
icant digit to the extent that a practical technical implementation may permit or
require it.
Unless defined otherwise, all technical and scientific terms used herein
have the same meaning as commonly understood by one of ordinary skill in the art to
which this technology belongs. Although any methods and materials similar or
equivalent to those described herein can also be used in the practice or testing of the
present technology, a limited number of the exemplary methods and materials are
described herein.
When a particular material is fied as being used to construct a
ent, s alternative materials with similar properties may be used as a
substitute. Furthermore, unless ied to the contrary, any and all components
herein described are understood to be capable of being manufactured and, as such,
may be manufactured together or separately.
It must be noted that as used herein and in the appended claims, the
ar forms "a", "an", and "the" include their plural equivalents, unless the context
clearly dictates otherwise.
All ations mentioned herein are incorporated herein by reference in
their entirety to disclose and describe the methods and/or als which are the
subject of those publications. The publications discussed herein are provided solely
for their disclosure prior to the filing date of the present application. Nothing herein is
to be construed as an admission that the present technology is not entitled to antedate
such publication by virtue of prior invention. Further, the dates of publication
provided may be ent from the actual publication dates, which may need to be
independently confirmed.
The terms "comprises" and ising" should be interpreted as
referring to elements, components, or steps in a non-exclusive manner, indicating that
the referenced elements, components, or steps may be present, or utilized, or
combined with other elements, components, or steps that are not expressly referenced.
The subject gs used in the detailed description are included only for
the ease of reference of the reader and should not be used to limit the t matter
found throughout the disclosure or the claims. The subject headings should not be
used in construing the scope of the claims or the claim limitations.
Although the technology herein has been described with reference to
particular examples, it is to be understood that these examples are merely illustrative
of the principles and applications of the technology. In some instances, the
terminology and symbols may imply specific details that are not required to practice
the technology. For example, although the terms "first" and "second" may be used,
unless otherwise specified, they are not intended to indicate any order but may be
ed to distinguish between ct elements. Furthermore, although process steps
in the methodologies may be described or illustrated in an order, such an ordering is
not required. Those skilled in the art will recognize that such ordering may be
modified and/or aspects thereof may be conducted concurrently or even
synchronously.
It is therefore to be understood that numerous modifications may be made
to the illustrative examples and that other arrangements may be devised t
departing from the spirit and scope of the technology.
Also, it should be appreciated that one or more aspects of the present
technology may be combinable with one or more aspects of: PCT Application No.
, filed September 23, 2016 and ed “Patient Interface”,
which claims the benefit of U.S. ional Application No. ,593, filed
September 23, 2015 and U.S. Provisional Application No. 62/376,961, filed August
19, 2016; U.S. Provisional ation No. 62/377,217, filed August 19, 2016 and
ed “Patient Interface with a Seal-Forming Structure having Varying ess”;
U.S. Provisional Application No. 62/377,158, filed August 19, 2016 and entitled
“Patient Interface with a Seal-Forming Structure having Varying Thickness”; PCT
Application No. , filed September 23, 2016 and entitled “Elbow
Assembly”, which claims the benefit of U.S. Provisional Application No. 62/222,435,
filed September 23, 2015 and U.S. Provisional Application No. 62/376,718, filed
August 18, 2016; U.S. Provisional ation No. 62/377,217, filed August 19, 2016
and entitled “Patient ace with a Seal-Forming Structure having Varying
Thickness”; U.S. Provisional Application No. ,158, filed August 19, 2016 and
entitled “Patient Interface with a Seal-Forming Structure having Varying Thickness”;
and/or PCT ation No. filed March 24, 2016 and entitled
“Patient Interface with Blowout Prevention for Seal-Forming Portion”, which claims
the benefit of U.S. Provisional Application No. 62/138,009, filed March 25, 2015 and
U.S. Provisional Application No. 62/222,503, filed September 23, 2015; each of the
above-noted applications of which is incorporated herein by reference in its ty.
.10 REFERENCE CHARACTERS LIST
patient 1000
bed partner 1100
t interface 3000
seal - forming structure 3100
plenum chamber 3200
positioning and stabilising structure 3300
rigidiser arm 3301
superior attachment point 3302
or strap connector 3303
inferior attachment point 3304
shroud 3305
clip 3306
hinge 3307
vent 3400
orifice 3402
wall 3404
diffusing member 3406
blocking member 3408
channels 3410
hole 3412
central hole 3414
radial opening 3416
elbow 3418
wall 3420
cap 3422
annular flange 3424
annular gap 3426
annular groove 3428
annular protrusion 3430
lip 3432
ball 3434
socket 3436
snap fit tion 3438
first half 3440
second half 3442
decoupling structure 3500
connection port 3600
forehead support 3700
RPT device 4000
external housing 4010
upper n 4012
lower portion 4014
panel 4015
chassis 4016
handle 4018
pneumatic block 4020
mechanical and pneumatic components 4100
air filter 4110
inlet air filter 4112
outlet air filter 4114
muffler 4120
inlet muffler 4122
outlet muffler 4124
pressure generator 4140
blower 4142
motor 4144
anti-spill back valve 4160
air circuit 4170
heated air circuit 4171
tube 4172
RPT device connector 4173
vent adaptor connector 4174
t connector 4175
grip recess 4176
seal 4177
tube connector 4178
supplemental oxygen 4180
electrical components 4200
printed t board assembly (PCBA) 4202
power supply 4210
input device 4220
central controller 4230
therapy device controller 4240
protection circuits 4250
memory 4260
transducer 4270
data communication interface 4280
output device 4290
algorithms 4300
pre - processing module 4310
pressure compensation algorithm 4312
vent flow rate tion algorithm 4314
leak flow rate estimation algorithm 4316
respiratory flow rate estimation algorithm 4318
therapy engine module 4320
fuzzy phase determination algorithm 4321
waveform determination algorithm 4322
ventilation determination algorithm 4323
inspiratory flow limitation determination thm 4324
apnea / hypopnea ination algorithm 4325
snore determination algorithm 4326
airway patency determination algorithm 4327
target ventilation determination algorithm 4328
therapy parameter determination algorithm 4329
therapy control module 4330
fault condition ion 4340
therapy device 4350
humidifier 5000
humidifier inlet 5002
humidifier outlet 5004
humidifier base 5006
humidifier reservoir 5110
conductive portion 5120
humidifier reservoir dock 5130
locking lever 5135
water level indicator 5150
humidifier transducer 5210
pressure transducer 5212
air flow rate transducer 5214
ature transducer 5216
humidity sensor 5218
heating element 5240
fier controller 5250
central humidifier controller 5251
heating element ller 5252
air circuit controller 5254
HME 7000
layer 7001
corrugated structure 7002
top structure 7010
superior channel 7012
base structure 7020
inferior channel 7022
corrugation 7030
upper folded portion 7031
fluid connector 9000
first end 9002
second end 9004
fluid conduit 9006
seal portion 9008
first opening 9010
latching n 9012
complementary latching portion 9014
sealing surface 9016
second opening 9018
second tube 9020
first tube 9022
inner n 9024
outer portion 9026
interface 9028
stop 9030
port 9032
overhang portion 9034
pressure tap 9036
guide portion 9038
vent adaptor 9100
conduit connector 9110
conduit end 9111
vent adaptor end 9112
anti - asphyxia valve (AAV) gs 9113
ring 9115
air circuit connector 9116
bayonet connector 9117
vent housing 9120
end 9121
protrusions 9122
tab 9123
lip 9124
al vent hole 9125
internal vent hole 9126
shoulder 9127
support 9128
notches 9129
vent diffuser cover 9130
anti - asphyxia valve (AAV) 9135
flap 9140
flap retaining structure 9141
HME material 9145
diffuser 9146
diffuser opening 9147
diffuser retaining ring 9148
radial diffuser retainer 9149
CFV ring 9150
vent housing connector 9160
first bar 9161
second bar 9162
receptacle 9163
notch 9164
curved outer e 9165
bayonet connector 9166
cavity 9167
HME clip 9170
arm 9171
central shaft 9172
shaft end 9173
arm ends 9174
HME housing 9180
slots 9181
cross - member 9182
receiver 9183
outer wall 9184
cut - outs 9185
s seal 9190
bellows seal connector 9191
outer surface 9192
inner surface 9193
shoulder surface 9194
vent adaptor connector 9200
orifice 9201
rim 9202
rim 9203
short tube assembly 9210
tube 9212
tube-housing connector 9214
tube-elbow connector 9216
elbow assembly 9220
elbow frame 9222
elbow overmould 9224
vent core structure 9300
inlet 9301
air t connector 9302
clip 9304
vent core extension 9306
outer orifices 9308
inner orifices 9310
alignment structure 9312
vent housing 9320
bayonet connector 9322
membrane retainer 9324
annular lip 9326
ing protrusion 9328
vent diffuser cover 9330
cover spacers 9332
connection surface 9334
posterior vent outlet 9340
anterior vent outlet 9342
HME housing 9400
patient-side HME housing portion 9402
atmosphere-side HME housing n 9404
annular recess 9405
patient-side HME housing portion cross-bar 9406
atmosphere-side HME housing portion cross-bar 9408
opening 9410
tab 9412
atmosphere-side HME housing portion ring 9414
HME inner housing 9416
HME bypass e 9418
lip seal 9500
baffle 9600
plenum chamber connector 9700
nasal cushion patient interface 3000A
nasal pillows patient interface 3000B
full face patient interface 3000C
vent system 13400
vent g 13401
outer wall 13402
outer base 13403
outer orifice 13404
lateral membrane support 13405
inner base 13406
inner orifice 13407
base connector 13408
membrane spacer 13409
inner wall 13410
inlet 13411
membrane spacer gap 13412
inner base slot 13413
recess divider 13414
recess 13415
membrane 13430
membrane opening 13431
patient-side surface 13432
atmosphere-side e 13433
inner surface 13434
outer surface 13435
Claims (20)
1. A vent assembly for a respiratory pressure therapy (RPT) system to provide a flow of pressurized gas at a therapeutic re of at least 6 cmH2O above ambient air pressure from a respiratory re therapy (RPT) device to a patient interface to treat a respiratory disorder, the vent assembly comprising: a vent housing having a first orifice configured to receive the flow of pressurized gas from the RPT device and the vent housing having a ity of holes to discharge pressurized gas to atmosphere; a vent housing connector having a second orifice configured to direct the flow of pressurized gas to the patient ace; a tube connected to the vent g connector at the second e, the tube being ured to be connected to the patient interface to direct the flow of pressurized gas to the patient interface; and a heat and moisture exchanger (HME) comprising an HME housing and an HME material within the HME housing, wherein the vent housing and the vent g connector are configured to be connected to, at least in part, form a cavity, wherein the HME is positioned in the cavity when the vent assembly is assembled, and wherein the HME housing is removably connected to the vent housing or the vent housing connector with a snap-fit.
2. The vent assembly of claim 1, further comprising an r lip extending from around an inner periphery of the vent housing and at least one retaining protrusion extending from the annular lip.
3. The vent assembly of claim 2, further comprising an annular recess extending around an outer periphery of the HME housing, wherein the at least one retaining protrusion and the annular recess are configured to removably connect the HME housing to the vent housing.
4. The vent assembly of claim 3, wherein the HME housing comprises a patientside HME housing n and an atmosphere-side HME housing portion, and wherein vent assembly is configured such that the patient-side HME housing portion is positioned closer to the patient than the here-side HME housing portion in use.
5. The vent assembly of claim 4, wherein the annular recess is ed to the atmosphere-side HME housing portion.
6. The vent assembly of claim 4, wherein the annular recess is ed to the patient-side HME housing portion.
7. The vent assembly of any one of claims 2 to 6, further comprising two retaining sions positioned opposite one r.
8. The vent assembly of claim 1, wherein an outer periphery of the HME housing includes retaining protrusions that may be removably received by a recess formed around an inner periphery of the vent housing or the vent housing connector.
9. The vent assembly of claim 1, wherein the HME g and the vent adaptor are removably connected with corresponding s.
10. The vent assembly of claim 1, wherein the HME housing is removably connected to the vent housing connector or the vent g 9320 with a bayonet connection.
11. The vent assembly of any one of claims 1 to 10, wherein the vent housing further comprises an annular surface around the first orifice and the plurality of holes pass through the annular surface, wherein the vent ly comprises a membrane positioned nt to the annular surface, and wherein the membrane is movable such that the membrane is urged against the annular surface of the vent housing as the pressure of the pressurized gas within the vent assembly increases.
12. The vent assembly of claim 11, wherein the plurality of holes comprises a first group of holes and a second group of holes, the first group of holes being proximal to the first orifice ve to the second group of holes.
13. The vent assembly of claim 12, wherein the membrane is shaped and ioned such that the membrane does not cover the second group of holes.
14. The vent assembly of claim 12 or 13, wherein the membrane is structured to cover more of the second group of holes as the pressure of the rized gas within the vent assembly increases.
15. The vent assembly of any of claims 12 to 14, wherein the first group of holes is positioned upstream of the second group of holes relative to the flow of pressurized
16. The vent ly of any of claims 11 to 15, further comprising a retaining structure to retain the membrane in a position adjacent to the annular surface of the vent housing.
17. The vent assembly of any of claims 11 to 16, wherein the membrane further comprises an elastic material.
18. The vent assembly of any of claims 1 to 17, wherein each of the plurality of holes has a shape that converges from an internal surface of the vent housing to an external surface of the vent housing.
19. An RPT system, comprising: the vent assembly of any of claims 1 to 18; an RPT device configured to generate the flow of pressurized gas; a patient interface configured to deliver the flow of pressurized gas to the patient’s airways, the patient interface being nted; and a delivery conduit ured to deliver the flow of pressurized gas from the RPT device to the vent assembly.
20. The RPT system of claim 19, wherein the RPT system does not include a humidifier. WO 26295
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US62/443,305 | 2017-01-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
NZ795793A true NZ795793A (en) | 2022-12-23 |
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