EP4701701A1 - Patient interface - Google Patents

Abstract

The invention relates to a patient interface providing for flow of pressurised air from a connection port to a seal-forming structure around the patient's airways. The patient interface includes a plenum chamber and a seal-forming structure, wherein the seal-forming structure is mounted to a flange provided to the plenum chamber and is at least partially formed by a textile layer. The plenum chamber includes a cutout, which in use corresponds to at least the nose bridge region of the patient's face, wherein the textile layer of the seal-forming structure covers the cutout.

Description

PATIENT INTERFACE

1 CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Australian Patent Application No. 2023901252, filed 28 April 2023 and Australian Patent Application No. 2023903314, filed 18 October 2023, each of which is hereby incorporated by reference herein in its entirety.

2 BACKGROUND OF THE TECHNOLOGY

2.1 FIELD OF THE TECHNOLOGY

[0002] The present technology relates to one or more of the screening, diagnosis, monitoring, 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

[0003] The respiratory system of the body facilitates gas exchange. The nose and mouth form the entrance to the airways of a patient.

[0004] 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 inhaled air into the venous blood and carbon dioxide to move in the opposite direction. 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 alveolated region of the lung is where the gas exchange takes place, and is referred to as the respiratory zone. See “Respiratory Physiology", by John B. West, Lippincott Williams & Wilkins, 9th edition published 2012.

[0005] A range of respiratory disorders exist. Certain disorders may be characterised by particular events, e.g. apneas, hypopneas, and hyperpneas.

[0006] Examples of respiratory disorders include Obstructive Sleep Apnea (OSA), Cheyne-Stokes Respiration (CSR), respiratory insufficiency, Obesity Hypoventilation Syndrome (OHS), Chronic Obstructive Pulmonary Disease (COPD), Neuromuscular Disease (NMD) and Chest wall disorders.

[0007] Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing (SDB), is characterised by events including 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 posterior oropharyngeal wall during sleep. The condition causes the affected patient to stop breathing for periods typically of 30 to 120 seconds in duration, sometimes 200 to 300 times per night. It often causes excessive daytime somnolence, and it may cause cardiovascular disease 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, e.g. see US Patent No. 4,944,310 (Sullivan).

[0008] Cheyne-Stokes Respiration (CSR) is another form of sleep disordered breathing. CSR is a disorder of a patient's respiratory controller in which there are rhythmic 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 repetitive arousal from sleep, which causes severe sleep disruption, increased sympathetic activity, and increased afterload, e.g. see US Patent No. 6,532,959 (Berthon-Jones).

[0009] Respiratory failure is an umbrella term for respiratory disorders in which the lungs are unable to inspire sufficient oxygen or exhale sufficient CO2 to meet the patient’s needs. Respiratory failure may encompass some or all of the following disorders.

[0010] A patient with respiratory insufficiency (a form of respiratory failure) may experience abnormal shortness of breath on exercise.

[0011] Obesity Hypoventilation Syndrome (OHS) is defined as the combination of severe obesity and awake chronic hypercapnia, in the absence of other known causes for hypoventilation. Symptoms include dyspnea, morning headache and excessive daytime sleepiness.

[0012] 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.

[0013] Neuromuscular 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 difficulties, respiratory muscle weakness and, eventually, death from respiratory failure. Neuromuscular 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 reduces life expectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic muscular dystrophy). Symptoms of respiratory failure in NMD include: increasing generalised weakness, dysphagia, dyspnea on exertion and at rest, fatigue, sleepiness, morning headache, and difficulties with concentration and mood changes.

[0014] Chest wall disorders are a group of thoracic deformities that result in inefficient coupling 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: dyspnea on exertion, peripheral oedema, orthopnea, repeated chest infections, morning headaches, fatigue, poor sleep quality and loss of appetite. [0015] 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 respiratory disorders from arising. However, these have a number of shortcomings.

2.2.2 Therapies

[0016] Various respiratory therapies, such as Continuous Positive Airway Pressure (CPAP) therapy, Non-invasive ventilation (NIV), Invasive ventilation (IV), and High Flow Therapy (HFT) have been used to treat one or more of the above respiratory disorders.

2.2.2.1 Respiratory pressure therapies

[0017] Respiratory pressure therapy is the application of a supply of air to an entrance to the airways at a controlled target pressure that is nominally positive with respect to atmosphere throughout the patient’s breathing cycle (in contrast to negative pressure therapies such as the tank ventilator or cuirass).

[0018] Continuous Positive Airway Pressure (CPAP) therapy 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 prevent 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: uncomfortable, difficult to use, expensive and aesthetically unappealing.

[0019] Non-invasive ventilation (NIV) provides ventilatory 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 failure, in forms such as OHS, COPD, NMD and Chest Wall disorders. In some forms, the comfort and effectiveness of these therapies may be improved.

[0020] Invasive ventilation (IV) provides ventilatory support to patients that are no longer able to effectively breathe themselves and may be provided using a tracheostomy tube or endotracheal tube. In some forms, the comfort and effectiveness of these therapies may be improved.

2.2.3 Respiratory Therapy Systems

[0021] These respiratory therapies may be provided by a respiratory therapy system or device. Such systems and devices may also be used to screen, diagnose, or monitor a condition without treating it.

[0022] A respiratory therapy system may comprise a Respiratory Pressure Therapy Device (RPT device), an air circuit, a humidifier, a patient interface, an oxygen source, and data management.

[0023] Another form of therapy system is a mandibular repositioning device.

2.2.3.1 Patient Interface

[0024] A patient 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 cmlTO relative to ambient pressure. For other forms of therapy, such as the delivery 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 cm ICO. For flow therapies such as nasal HFT, the patient interface is configured to insufflate the nares but specifically to avoid a complete seal. One example of such a patient interface is a nasal cannula.

[0025] Certain 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 for 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 pressure than ambient.

[0026] 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.

[0027] 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 to create and maintain a seal via their lips.

[0028] 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.

[0029] Certain masks may cause some patients a feeling of claustrophobia, unease and/or may feel overly obtrusive. [0030] The design of a patient interface presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of noses and heads varies considerably between individuals. Since the head includes 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.

[0031] Consequently, some masks suffer from being obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and/or uncomfortable especially when worn for long or when a patient is unfamiliar with a system.

[0032] One cause of some masks being relatively bulky around the patient’s nose is the need to ensure that the nose does not come into contact with the hard surfaces of the plenum chamber walls, particularly the anterior wall. This requirement means that a generous space must be provided between posterior and anterior walls of the plenum chamber, to ensure that even patients with relatively large noses can wear the mask comfortably.

[0033] Wrongly sized masks can give rise to reduced compliance, reduced comfort and poorer patient outcomes. Masks designed solely for aviators, masks designed as part of personal 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 uncomfortable to be worn for extended periods of time, e.g., several hours. This discomfort may lead to a reduction in patient compliance with therapy, especially if the mask is to be worn during sleep.

[0034] CPAP therapy is highly effective to treat certain respiratory disorders, provided patients comply with therapy. 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 disassemble), patients may not clean their mask and this may impact on patient compliance.

[0035] While a mask for other applications (e.g. aviators) may not be suitable for use in treating sleep disordered breathing, a mask designed for use in treating sleep disordered breathing may be suitable for other applications.

[0036] For these reasons, patient interfaces for delivery of CPAP during sleep form a distinct field.

2.2.3.1.1 Seal-forming structure

[0037] Patient interfaces may include a seal-forming structure. Since it is in direct contact with the patient’s face, the shape and configuration of the seal-forming structure can have a direct impact the effectiveness and comfort of the patient interface.

[0038] A patient interface may be partly characterised according to the design intent of where the seal-forming structure is to engage with the face in use. In one form of patient interface, a seal-forming structure may comprise a first sub-portion to form a seal around the left naris and a second sub-portion to form a seal around the right naris. In one form of patient interface, a seal-forming structure 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 patient interface a seal-forming structure may comprise an element 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 structure may comprise a single element 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, full-face masks, nasal pillows, nasal puffs and oro-nasal masks.

[0039] A seal-forming structure that may be effective in one region of a patient’s face may be inappropriate in another region, e.g. because 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. [0040] Certain parts of the patient's anatomy may react differently to having a seal forming structure pressing against them. For example, the area around the bridge of the nose may have relatively thin skin and a lack of underlying soft tissue, and so may be at greater risk of comfort issues and skin breakdown issues relative to some other parts of the face.

[0041] Certain seal-forming structures may be designed for mass manufacture such that one design is able to 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 structure of the mass-manufactured patient interface, one or both must adapt in order for a seal to form.

[0042] One type of seal-forming structure extends around the periphery of the patient interface, and is intended to seal against the patient's face when force is applied to the patient interface with the seal-forming structure in confronting engagement with the patient's face. The seal-forming structure may include an air or fluid filled cushion, or a moulded or formed surface of a resilient seal element made of an elastomer such as a rubber. With this type of seal-forming structure, if the fit is not adequate, there will be gaps between the seal-forming structure and the face, and additional force will be required to force the patient interface against the face in order to achieve a seal.

[0043] Another type of seal-forming structure 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 seal-forming structure does not match that of the patient, it may crease or buckle in use, giving rise to leaks.

[0044] Another type of seal-forming structure may comprise a friction-fit element, e.g. for insertion into a naris, however some patients find these uncomfortable.

[0045] Another form of seal-forming structure may use adhesive to achieve a seal. Some patients may find it inconvenient to constantly apply and remove an adhesive to their face. [0046] A range of patient interface seal-forming structure technologies are disclosed in the following patent applications: WO 1998/004310; WO 2006/074513; WO 2010/135785. [0047] 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.

[0048] ResMed Inc. has manufactured the following products that incorporate nasal pillows: SWIFT™ nasal pillows mask, SWIFT™ II nasal pillows mask, SWIFT™ LT nasal pillows mask, SWIFT™ FX nasal pillows mask and MIRAGE LIBERTY™ full-face mask. The following patent applications describe examples of nasal pillows masks: International Patent Application WO 2004/073778 (describing amongst other things aspects of the SWIFT™ nasal pillows mask), US Patent Application 2009/0044808 (describing amongst other things aspects of the SWIFT™ LT nasal pillows mask); International Patent Applications WO 2005/063328 and WO 2006/130903 (describing amongst other things aspects of the MIRAGE LIBERTY™ full-face mask); International Patent Application WO 2009/052560 (describing amongst other things aspects of the SWIFT™ FX nasal pillows mask).

2.2.3.1.2 Positioning and Stabilising Structure

[0049] A seal-forming structure of a patient interface used for positive air pressure therapy is subject to the corresponding force of the air pressure to disrupt a seal. Thus a variety of techniques have been used to position the seal-forming structure, and to maintain it in sealing relation with the appropriate portion of the face. Several factors may be considered when comparing different positioning and stabilising techniques. These include: how effective the technique is at maintaining the seal-forming structure in the desired position and in sealed engagement with the face during use of the patient interface; how comfortable the interface is for the patient; whether the patient feels intrusiveness and/or claustrophobia when wearing the patient interface; and aesthetic appeal.

[0050] One technique is the use of adhesives, e.g. see US Patent Application Publication No. US 2010/0000534. However, the use of adhesives may be uncomfortable for some.

[0051] 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 Pressurised Air Conduit

[0052] In one type of treatment system, a flow of pressurised air is provided to a patient interface through a conduit in an air circuit that fluidly connects to the patient interface at a location that is in front of the patient’s face when the patient interface is positioned on the patient’s face during use. The conduit may extend from the patient interface forwards away from the patient’s face.

2.2.3.1.4 Pressurised Air Conduit used for Positioning I Stabilising the Seal-Forming Structure

[0053] Another type of treatment system comprises a patient interface in which a tube that delivers pressurised air to the patient’s airways also functions as part of the headgear to position and stabilise the seal-forming portion of the patient interface at the appropriate part of the patient’s face. This type of patient interface may be referred to as having “conduit headgear” or “headgear tubing”. Such patient interfaces allow the conduit in the air circuit providing the flow of pressurised air from a respiratory pressure therapy (RPT) device to connect to the patient interface in a position other than in front of the patient’s face. One example of such a treatment system is disclosed in US Patent Publication No. US 2007/0246043, the contents of which are incorporated herein by reference, in which the conduit connects to a tube in the patient interface through a port positioned in use on top of the patient’s head.

[0054] It is desirable for patient interfaces incorporating headgear tubing to be comfortable for a patient to wear over a prolonged duration when the patient is asleep, form an air-tight and stable seal with the patient’s face, while also able to fit a range of patient head shapes and sizes.

2.2.3.2 Respiratory Pressure Therapy (RPT) Device

[0055] A respiratory pressure therapy (RPT) device may be used individually or as part of a system to deliver one or more of a number of therapies described above, such as by operating the device to generate a flow of air for delivery to an interface to the airways. The flow of air may be pressure-controlled (for respiratory pressure therapies) or flow-controlled (for flow therapies such as HFT). Thus RPT devices may also act as flow therapy devices. Examples of RPT devices include a CPAP device and a ventilator.

[0056] The designer of a device may be presented with an infinite 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 Air circuit

[0057] An air circuit is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components of a respiratory therapy system such as the RPT device and the patient interface. In some cases, there may be separate limbs of the air circuit for inhalation and exhalation. In other cases, a single limb air circuit is used for both inhalation and exhalation.

2.2.3.4 Humidifier

[0058] 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.

2.2.3.5 Data Management

[0059] There may be clinical reasons to obtain data to determine whether the patient prescribed with respiratory therapy has been “compliant”, e.g. that the patient has used their RPT device according to one or more “compliance rules”. 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 provider 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 predetermined time period, and compare with the compliance 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.

[0060] There may be other aspects of a patient’s therapy that would benefit from communication of therapy data to a third party or external system.

[0061] Existing processes to communicate and manage such data can be one or more of costly, time-consuming, and error-prone.

2.2.3.6 Vent technologies

[0062] Some forms of treatment systems 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 a patient interface, e.g., the plenum chamber, to an exterior of the patient interface, e.g., to ambient. [0063] 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 insufficient 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.

2.2.4 Screening, Diagnosis, and Monitoring Systems

[0064] Polysomnography (PSG) is a conventional system for diagnosis and monitoring of cardio-pulmonary disorders, and typically involves expert clinical staff to apply the system. PSG typically involves the placement of 15 to 20 contact sensors on a patient in order to record various bodily signals such as electroencephalography (EEG), electrocardiography (ECG), electrooculograpy (EOG), electromyography (EMG), etc. PSG for sleep disordered breathing has involved two nights of observation of a patient in a clinic, one night of pure diagnosis and a second night of titration of treatment parameters by a clinician. PSG is therefore expensive and inconvenient. In particular, it is unsuitable for home screening / diagnosis / monitoring of sleep disordered breathing.

[0065] Screening and diagnosis generally describe the identification of a condition from its signs and symptoms. Screening typically gives a true / false result indicating whether or not a patient’s SDB is severe enough to warrant further investigation, while diagnosis may result in clinically actionable information. Screening and diagnosis tend to be one-off processes, whereas monitoring the progress of a condition can continue indefinitely. Some screening / diagnosis systems are suitable only for screening / diagnosis, whereas some may also be used for monitoring.

[0066] Clinical experts may be able to screen, diagnose, or monitor patients adequately based on visual observation of PSG signals. However, there are circumstances where a clinical expert may not be available, or a clinical expert may not be affordable. Different clinical experts may disagree on a patient’s condition. In addition, a given clinical expert may apply a different standard at different times.

3 BRIEF SUMMARY OF THE TECHNOLOGY

[0067] The present technology is directed towards providing medical devices used in the screening, diagnosis, monitoring, amelioration, treatment, or prevention of respiratory disorders having one or more of improved comfort, cost, efficacy, ease of use and manufacturability.

[0068] A first aspect of the present technology relates to apparatus used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of a respiratory disorder.

[0069] Another aspect of the present technology relates to methods used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of a respiratory disorder.

[0070] An aspect of certain forms of the present technology is to provide methods and/or apparatus that improve the compliance of patients with respiratory therapy.

[0071] One form of the present technology comprises a positioning and stabilising structure configured to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient’s head. The positioning and stabilising structure includes at least one strap.

[0072] One form of the present technology comprises a patient interface comprising a plenum chamber, a seal-forming structure, and a positioning and stabilising structure. [0073] One form of the present technology comprises a patient interface comprising a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure. The plenum chamber includes at least one plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient. The patient interface also comprises a seal-forming structure that is constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways. The seal-forming structure has a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares. The sealforming structure is constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use. The patient interface also comprises a positioning and stabilising structure to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient’s head.

[0074] Another aspect of one form of the present technology is a series of modular elements that may be interconnected in order to form different styles of patient interfaces. [0075] In one form, there are at least two versions or styles of each modular element. The versions or styles may be interchangeably used with one another in order to form different modular assemblies.

[0076] One form of the present technology comprises a patient interface constructed and arranged to form a seal with a region of the patient’s face, including a nose bridge region, and surrounding an entrance to the patient’s airways, the patient interface including: a plenum chamber defined, at least in part, by a chassis or chassis portion, wherein at least a portion of a perimeter of the chassis portion comprises a flange; a seal-forming structure, wherein the seal forming structure includes a foam layer, wherein the foam layer has an anterior side and a posterior side, and wherein the anterior side is bonded or otherwise secured to a patient-facing side of the flange, the seal-forming structure also including a textile layer, wherein the textile layer has a patient-contacting side and non-patient contacting side, and wherein the non-patient contacting side of the textile layer is bonded or otherwise secured to the patient-facing side of the foam layer such that, in use, the patient-contacting side of the textile layer contacts the patient’s face; and wherein the perimeter of the chassis includes a cutout, which in use, corresponds to the nose bridge region of the patient’s face, wherein the textile layer covers the cutout. [0077] Another aspect of one form of the present technology comprises a patient interface as defined above and a positioning and stabilising structure configured and arranged to maintain the seal-forming structure in a substantially sealing relation with the appropriate portion of the face of a patient. [0078] In examples: a. The chassis may be rigid or semi-rigid. b. The chassis may be configured to receive one of: a connector for an air circuit; an air circuit, or decoupling structure. c. The chassis may be configured to receive a frame on an anterior/exterior surface. d. The flange extends inward. e. The flange terminates at or proximate the cutout of the chassis. f. The flange may have a posterior side. g. The anterior side of the foam layer of the seal-forming structure may be adhesively bonded or otherwise secured to the posterior side of the flange. h. The foam layer may have an outer perimeter that is flush with the outer perimeter of the chassis when secured to the flange. i. The width dimension of the foam layer is greater than the width dimension of the flange. j. The textile layer may be adhesively bonded or otherwise secured to the posterior side of the foam layer. k. The textile layer may include an integral superior portion arranged and/or configured to be folded over and cover the cutout of the chassis. l. At least a portion of the patient contacting side of the superior portion of the textile layer covers, in use, the cutout of the chassis. m. The textile layer may include a separate superior portion configured to be adhesively bonded, welded or otherwise secured to the chassis to cover the cutout of the chassis. n. The superior portion of the textile layer may be mechanically secured to the cutout of the chassis. o. The textile layer may be arranged to, in use, apply a tensile force to the nose bridge region of the patient. p. The textile layer may be impermeable to air. q. The non-patient contacting surface of the textile may be coated with a layer or membrane of silicone. r. The chassis of the plenum chamber may include a second cutout, which in use, corresponds to the chin/lip inferior/supramenton region of the patient’s face. s. The flange may terminate at or proximate the second cutout of the chassis t. The foam layer may span the second cutout. u. The textile layer may include an integral inferior portion arranged and/or configured to be folded over and cover the second cutout of the chassis. v. The textile layer may be adhesively bonded, welded or otherwise secured to the chassis to cover the second cutout of the chassis. w. The textile layer may include a separate inferior portion configured to be adhesively bonded or otherwise secured to the chassis to cover the second cutout of the chassis. x. The inferior portion of the textile layer may be mechanically secured to the second cutout of the chassis. y. The patient interface is one of: an ora-nasal mask or a nasal mask.

[0079] One form of the present technology comprises a patient interface constructed and arranged to form a seal with a region of the patient’s face, including a nose bridge region, and surrounding an entrance to the patient’s airways, the patient interface including: a chassis or chassis portion having a perimeter and wherein a posterior/interior side of the chassis defines, at least in part, an air chamber, and wherein a portion of the perimeter is configured with a flange; a seal-forming structure, wherein the seal forming structure includes a foam layer, wherein the foam layer has an anterior side and a posterior side, and wherein the anterior side is bonded or otherwise secured to the patient-contacting side of the flange of the chassis, the seal-forming structure also including a textile layer, wherein the textile layer has a patient-contacting surface and non-patient contacting surface, and wherein the bonding surface of the textile layer is bonded or otherwise secured to the patient-contacting side of the foam layer such that, in use, the patient-contacting surface contacts a patient’s face; and wherein the perimeter of the chassis includes a cutout, which in use, corresponds to the nose bridge region of the patient’s face.

[0080] Another form of the present technology comprises a patient interface constructed and arranged to form a seal with a region of the patient’s face, including a nose bridge region, and surrounding an entrance to the patient’s airways, the patient interface including: a plenum chamber defined, at least in part, by a chassis portion, wherein at least a portion of a perimeter of the chassis portion comprises a flange, and wherein at least the portion of the chassis portion, including the flange, is relatively flexible, a seal-forming structure, wherein the seal forming structure includes a textile layer, wherein the textile layer has a patient-contacting side and non-patient contacting side, and wherein the non-patient contacting side of the textile layer is bonded or otherwise secured to the flange such that, in use, the patient-contacting side of the textile layer contacts the patient’s face; and wherein the perimeter of the chassis includes a cutout, which in use corresponds to at least the nose bridge region of the patient’s face, wherein the textile layer covers the cutout.

[0081] In examples; a. the chassis portion is made from a material having a Shore A hardness of between 30 and 60; b. the cutout extends to an anterior wall of the chassis; c. the portion of the cutout in the anterior wall of the chassis has a substantially inverted teardrop or inverted triangle shape; d. no flange is provided to the cutout; e. the flange terminates at sides of nose portions which are configured to engage portions of the sides of the patient’s nose corresponding to the nasal bone; f. the sides of nose portions are configured to avoid engagement with the portion of the patient’s nose corresponding to the greater alar cartilage; g. the sides of nose portions are configured to avoid engagement with the portion of the patient’s nose corresponding to the septum cartilage; h. the flange curves inward; i. the flange has a substantially “C” shape profile; j. a curvature of the flange is substantially continuous with a curvature of an immediately adjacent portion of the chassis; k. the flange has a thickness of between 2.5mm and 0.5mm; l. the flange has a free edge; m. the thickness of the flange tapers down toward the free edge; n. the textile layer is formed from a single piece of textile; o. the textile layer is cut from a flat sheet of textile; p. the textile layer comprises a stretchable material; q. the textile layer is substantially impermeable to air; r. one or more regions of, or all of, the textile layer may allow a limited flow of air; s. the textile layer may comprise a thin layer of elastomer; t. the textile layer may comprise a main portion, a superior portion, and a necked portion between the main and superior portions; u. the necked portion of the textile layer forms a nasal bridge sealing portion; v. the nasal bridge sealing portion has a concave shape; w. at least portions of the textile layer may extend beyond the free edge of the flange to form at least one unsupported portion of the textile layer; x. the unsupported portion of the textile layer may have a uniform width; y. the textile layer may comprises unsupported portions having varying widths; z. the unsupported portion(s) may have a width of substantially 2mm; aa. at least a portion of the flange is not covered by the textile layer, wherein the portion of the flange which is not covered by the textile layer is configured to seal against the patient’s face; bb. the chassis may comprise a shell portion which is more rigid than the remainder of the chassis portion; cc. the shell portion does not extend to the lateral or inferior walls of the chassis; dd. the shell portion may have a Shore A hardness of greater than 60; ee. the shell portion may be made from a nylon, a polyester, a semi-rigid elastomer, or silicone; ff. the shell portion may form at least part of an anterior wall of the chassis; gg. the cutout may extend to the shell portion; and/or hh. the anterior wall of the chassis portion may comprise a layer of relatively flexible material with a shell portion connected to an outer surface of the relatively flexible material.

[0082] Another aspect of one form of the present technology is a patient interface that is moulded or otherwise constructed with a perimeter shape which is complementary to that of an intended wearer.

[0083] An aspect of one form of the present technology is a method of manufacturing apparatus.

[0084] Another aspect of one form of the present technology is a method of assembling a modular system comprising selecting a positioning and stabilising structure, and connecting the positioning and stabilising structure to either a first cushion or a second cushion.

[0085] An aspect of certain forms of the present technology is a medical device that is easy to use, e.g. by a person who does not have medical training, by a person who has limited dexterity, vision or by a person with limited experience in using this type of medical device. [0086] An aspect of one form of the present technology is a portable RPT device that may be carried by a person, e.g., around the home of the person.

[0087] An aspect of one form of the present technology is a patient interface that may be washed in a home of a patient, e.g., in soapy water, without requiring specialised cleaning equipment. An aspect of one form of the present technology is a humidifier tank that may be washed in a home of a patient, e.g., in soapy water, without requiring specialised cleaning equipment.

[0088] The methods, systems, devices and apparatus described may be implemented so as to improve the functionality of a processor, such as a processor of a specific purpose computer, respiratory monitor and/or a respiratory therapy apparatus. Moreover, the described methods, systems, devices and apparatus can provide improvements in the technological field of automated management, monitoring and/or treatment of respiratory conditions, including, for example, sleep disordered breathing.

[0089] 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.

[0090] 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 DESCRIPTION OF THE DRAWINGS

[0091] 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 elements including:

4.1 RESPIRATORY THERAPY SYSTEMS

[0092] Fig. 1A shows a system including a patient 1000 wearing a patient interface 3000, in the form of nasal pillows, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device 4000 is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown. The patient is sleeping in a supine sleeping position.

[0093] Fig. IB shows a system including 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 patient 1000.

[0094] 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 humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. The patient is sleeping in a side sleeping position.

4.2 RESPIRATORY SYSTEM AND FACIAL ANATOMY

[0095] Fig. 2A shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, alveolar sacs, heart and diaphragm.

[0096] Fig. 2B shows a view of a human upper airway including the nasal cavity, nasal bone, lateral nasal cartilage, greater alar cartilage, nostril, lip superior, lip inferior, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea. [0097] Fig. 2C is a front view of a face with several features of surface anatomy identified including the lip superior, upper vermilion, lower vermilion, lip inferior, mouth width, endocanthion, a nasal ala, nasolabial sulcus and cheilion. Also indicated are the directions superior, inferior, radially inward and radially outward.

[0098] Fig. 2D is a side view of a head with several features of surface anatomy identified including 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.

[0099] Fig. 2E is a further side view of a head. The approximate locations of the Frankfort horizontal and nasolabial angle are indicated. The coronal plane is also indicated. [0100] Fig. 2F shows a base view of a nose with several features identified including naso-labial sulcus, lip inferior, upper Vermilion, naris, subnasale, columella, pronasale, the major axis of a naris and the midsagittal plane.

[0101] Fig. 2G shows a side view of the superficial features of a nose.

[0102] Fig. 2H shows subcutaneal structures of the nose, including lateral cartilage, septum cartilage, greater alar cartilage, lesser alar cartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue, frontal process of the maxilla and fibrofatty tissue.

[0103] Fig. 21 shows a medial dissection of a nose, approximately several millimeters from the midsagittal plane, amongst other things showing the septum cartilage and medial crus of greater alar cartilage.

[0104] 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.

[0105] Fig. 2K shows a lateral view of a skull with the outline of the surface of a head, as well as several muscles. The following bones are shown: frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal, temporal and occipital. The mental protuberance is indicated. The following muscles are shown: digastricus, masseter, sternocleidomastoid and trapezius.

[0106] Fig. 2L shows an anterolateral view of a nose.

4.3 PATIENT INTERFACE

[0107] Fig. 3 A shows a patient interface in the form of a nasal mask in accordance with one form of the present technology.

[0108] Fig. 3A-1 shows forces acting on the patient interface of Fig. 3A, while in use.

[0109] 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.

[0110] Fig. 3C 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 small magnitude when compared to the magnitude of the curvature shown in Fig. 3B.

[0111] Fig. 3D 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 value of zero.

[0112] 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 relatively small magnitude when compared to the magnitude of the curvature shown in Fig. 3F.

[0113] 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.

[0114] 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.

[0115] Fig. 3H shows a cushion for a mask. An exterior surface of the cushion is indicated. An edge of the surface is indicated. A path on the surface between points A and B is indicated. A straight line distance between A and B is indicated. Two saddle regions and a dome region are indicated.

[0116] Fig. 31 shows the surface of a structure, with a one dimensional hole in the surface. The illustrated plane curve forms the boundary of a one dimensional hole.

[0117] Fig. 3J shows a cross-section through the structure of Fig.3I. The illustrated surface bounds a two dimensional hole in the structure of Fig. 31.

[0118] Fig. 3K shows a perspective view of the structure of Fig. 31, including the two dimensional hole and the one dimensional hole. Also shown is the surface that bounds a two dimensional hole in the structure of Fig. 31.

[0119] Fig. 3L shows a mask having an inflatable bladder as a cushion.

[0120] Fig. 3M shows a cross-section through the mask of Fig. 3L, and shows the interior surface of the bladder. The interior surface bounds the two dimensional hole in the mask.

[0121] Fig. 3N shows a further cross-section through the mask of Fig. 3L. The interior surface is also indicated.

[0122] Fig. 30 illustrates a left-hand rule.

[0123] Fig. 3P illustrates a right-hand rule.

[0124] Fig. 3Q shows a left ear, including the left ear helix.

[0125] Fig. 3R shows a right ear, including the right ear helix.

[0126] Fig. 3S shows a right-hand helix. [0127] Fig. 3T shows a view of a mask, including the sign of the torsion of the space curve defined by the edge of the sealing membrane in different regions of the mask.

[0128] Fig. 3U shows a view of a plenum chamber 3200 showing a sagittal plane and a mid-contact plane.

[0129] Fig. 3 V shows a view of a posterior of the plenum chamber of Fig. 3U. The direction of the view is normal to the mid-contact plane. The sagittal plane in Fig. 3V bisects the plenum chamber into left-hand and right-hand sides.

[0130] Fig. 3W shows a cross-section through the plenum chamber of Fig. 3 V, the cross-section being taken at the sagittal plane shown in Fig. 3V. A ‘mid-contact’ plane is shown. The mid-contact plane is perpendicular to the sagittal plane. The orientation of the mid-contact plane corresponds to the orientation of a chord 3210 which lies on the sagittal plane and just touches the cushion of the plenum chamber at two points on the sagittal plane: a superior point 3220 and an inferior point 3230. Depending on the geometry of the cushion in this region, the mid-contact plane may be a tangent at both the superior and inferior points. [0131] Fig. 3X shows the plenum chamber 3200 of Fig. 3U in position for use on a face. The sagittal plane of the plenum chamber 3200 generally coincides with the midsagittal plane of the face when the plenum chamber is in position for use. The mid-contact plane corresponds generally to the ‘plane of the face’ when the plenum chamber is in position for use. In Fig. 3X the plenum chamber 3200 is that of a nasal mask, and the superior point 3220 sits approximately on the sellion, while the inferior point 3230 sits on the lip superior.

[0132] Fig. 3Y shows a patient interface in the form of a nasal cannula in accordance with one form of the present technology.

[0133] Fig. 3Z shows a patient interface having conduit headgear, in accordance with one form of the present technology.

[0134] Fig. 3Z-1 shows forces acting on the patient interface of Fig. 3Z, while in use.

4.4 RPT DEVICE

[0135] Fig. 4A shows an RPT device in accordance with one form of the present technology.

[0136] 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 with reference to the blower and the patient interface. The blower is defined to be upstream of the patient interface and the patient interface is defined to be downstream of the blower, regardless of the actual flow direction at any particular moment. Items which are located within the pneumatic path between the blower and the patient interface are downstream of the blower and upstream of the patient interface. 4.5 HUMIDIFIER

[0137] Fig. 5 A shows an isometric view of a humidifier in accordance with one form of the present technology.

[0138] 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.

4.6 BREATHING WAVEFORMS

[0139] Fig. 6 shows a model typical breath waveform of a person while sleeping.

4.7 MODUEARITY

[0140] Fig. 7A shows a perspective view of a cushion of a patient interface configured to be worn by a patient and convey pressurized air to the patient’s nose and the patient’s mouth.

[0141] Fig. 7B shows a perspective view of a cushion of a patient interface configured to be worn by a patient and convey pressurized air to the patient’s nose.

[0142] Fig. 7C shows a perspective view of tubes usable with either the cushion of Fig.

7A or the cushion of Fig. 7B.

[0143] Fig. 7D shows a perspective view of rigidiser arms usable with either the cushion of Fig. 7A of the cushion of Fig. 7B.

[0144] Fig. 7E shows a perspective view of headgear straps usable with the cushion of Fig. 7A.

[0145] Fig. 7F shows a perspective view of headgear straps usable with the cushion of Fig. 7B.

[0146] Fig. 7G shows a front view of a pair of sleeves that is removably fitted to either the tubes of Fig. 7C or the rigidiser arms of Fig. 7D.

[0147] Fig. 7H shows a front view of a full sleeve that is removably fitted to the rigidiser arms of Fig. 7D.

[0148] Fig. 71 shows a front perspective view of yet another alternate form of a full sleeve that is removably fitted to the rigidiser arms of Fig. 7D.

[0149] Fig. 7J is a front view of a patient wearing the cushion of Fig. 7A connected to the tubes of Fig. 7C, the headgear straps of Fig. 7E, and the sleeves of Fig. 7G.

[0150] Fig. 7K is a front view of a patient wearing the cushion of Fig. 7A connected to the rigidiser arms of Fig. 7D, the headgear straps of Fig. 7E, and the sleeve of Fig. 7H.

[0151] Fig. 7E is a front view of a patient wearing the cushion of Fig. 7B connected to the conduit headgear of Fig. 7C, and the headgear straps of Fig. 7F.

[0152] Fig. 7M is a front view of a patient wearing the cushion of Fig. 7B connected to the rigidisier arms of Fig. 7D, the headgear straps of Fig. 7F, and the sleeve of Fig. 71.

[0153] Fig. 7N is an isolated perspective view of the vent of Fig. 7E. [0154] Fig. 70 is an isolated perspective view of a portion of the air circuit of Fig. 7M.

[0155] Fig. 7P is a schematic view illustrating the possible combinations of the patient interfaces.

4.8 EXAMPLES OF THE PRESENT TECHNOLOGY

[0156] Fig. 8 shows an exploded perspective view of a cushion module for a patient inference in accordance with one form of the present technology.

[0157] Fig. 9 A shows a view of the posterior side of the chassis of the plenum chamber of Fig. 8.

[0158] Fig. 9B shows a top view of the superior side of the chassis of the plenum chamber of Figs. 8 and 9A.

[0159] Fig. 10 shows a view of the posterior side of the chassis of the plenum chamber with the seal-forming structure in place.

[0160] Fig. 11 A shows a first detail cross-sectional view of a portion of the superior side of the chassis and seal-forming structure of the plenum chamber of Fig. 10.

[0161] Fig. 1 IB shows a second detail cross-sectional view of a portion of the superior side of the chassis and seal-forming structure of the plenum chamber of Fig. 11 A after application of a compressive force upon the seal-forming structure.

[0162] Fig. 12A shows a view of the posterior side of a textile layer for application to the seal-forming structure of Fig. 10.

[0163] Fig. 12B shows a view of the posterior side of the chassis of the plenum chamber with the textile layer applied to the seal-forming structure.

[0164] Fig. 12C shows a top view of the superior side of the chassis of the plenum chamber of Fig. 12B.

[0165] Fig. 12D shows a bottom view the inferior side of the chassis of the plenum chamber of Figs. 12B and 12C.

[0166] Fig. 13 shows a detail cross-sectional top view of a portion of the superior side of the chassis, seal-forming structure and the applied textile blank, of the plenum chamber of Figs. 12B to 12D.

[0167] Fig. 14 shows a front perspective assembled view of the anterior side of the cushion module of Fig. 8.

[0168] Fig. 15A is a front view of a cushion module according to another form of the technology in position on a patient’s face, with headgear not shown.

[0169] Fig. 15B is a rear view of the cushion module of Fig. 15 A.

[0170] Fig 15C is a front perspective view of the cushion module of Fig. 15A.

[0171] Fig 15D is a rear perspective view of the cushion module of Fig. 15A.

[0172] Fig 15E is a perspective view from the rear and one side of the cushion module of Fig. 15 A. [0173] Fig. 15F is a cross-section side view of the cushion module of Fig 15A in position on the patient’s face.

[0174] Fig. 15G is an enlarged view of the nose bridge portion of the textile layer viewed in the direction of arrow A in Fig. 15B.

[0175] Fig. 16A is a front view of a chassis portion of the cushion module of Fig. 15A. [0176] Fig. 16B is a rear view of the chassis portion of Fig. 15 A.

[0177] Fig. 16C is a front view of the chassis portion of Fig.15A shown in an in-use position on a patient’s face.

[0178] Fig. 17 is a front view of a textile layer component.

[0179] Fig. 18 is rear view of a cushion module according to another form of the technology.

[0180] Fig. 19 is an enlarged cross-section view of a flange and textile layer of a cushion module according to one form of the technology.

[0181] Fig. 20A is a front view of a cushion module according to another form of the technology.

[0182] Fig. 20B is a side view of the cushion module of Fig. 20A.

[0183] Fig. 20C is an enlarged cross-section view of a flange and textile layer of the cushion module of Fig. 20A.

[0184] Fig. 21 an enlarged cross-section view of a flange and textile layer of the cushion module according to another form of the technology.

5 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

[0185] Before the present technology is described in further detail, it is to be understood that the technology is not limited to the particular examples described herein, which may vary. It is also to be understood that the terminology used in this disclosure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting. [0186] The following description 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 examples may constitute a further example.

5.1 THERAPY

[0187] In one form, the present technology comprises a method for treating a respiratory disorder comprising applying positive pressure to the entrance of the airways of a patient 1000.

[0188] 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. [0189] In certain examples of the present technology, mouth breathing is limited, restricted or prevented.

5.2 RESPIRATORY THERAPY SYSTEMS

[0190] In one form, the present technology comprises a respiratory therapy system for treating a respiratory disorder. The respiratory therapy system may comprise an RPT device 4000 for supplying a flow of air to the patient 1000 via an air circuit 4170 and a patient interface 3000 or 3800.

5.3 PATIENT INTERFACE

[0191] A non-invasive patient interface 3000, such as that shown in Fig. 3 A, in accordance with one aspect of the present technology comprises 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 connection to air circuit 4170, and a forehead support 3700. In some forms a functional aspect may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use the seal-forming structure 3100 is arranged to surround an entrance to the airways of the patient so as to maintain positive pressure at the entrance(s) to the airways of the patient 1000. The sealed patient interface 3000 is therefore suitable for delivery of positive pressure therapy.

[0192] As shown in Fig. 3Z, a non-invasive patient interface 3000 in accordance with another aspect of the present technology comprises the following functional aspects: a sealforming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300, a vent 3400 and one form of connection port 3600 for connection to an air circuit (such as the air circuit 4170 shown in Figs. 1A-1C). A cushion module 3150 may define the plenum chamber 3200, at least in part.

[0193] In the example shown in these figures, the plenum chamber 3200 and sealforming structure 3100 functional aspects are provided by one physical component. In this example, the cushion module 3150 provides both the plenum chamber 3200 and the sealforming structure 3100 functional aspects of the patient interface 3000. The seal-forming structure 3100 and other wall portions of the cushion module 3150 form the plenum chamber 3200 in this example.

[0194] The cushion module 3150 may be modular in the sense that it can be replaced in the patient interface 3000 with another cushion module 3150. In some examples a first cushion module 3150 of the patient interface may be able to be replaced by a second cushion module 3150, the second cushion module 3150 being a different type of cushion module from the first cushion module 3150. For example, the second cushion module 3150 may have a different size, shape and/or structure from the first cushion module. [0195] In other forms of the present technology, the plenum chamber 3200 and sealforming structure 3100 may be inseparable from components of the positioning and stabilising structure 3300. For example, a cushion module 3150 fully or partially forming the plenum chamber 3200 may be permanently connected to one or more other components of the patient interface 3000. The cushion module 3150 in such an example of the present technology may be modular in the sense that is a sub-part of a larger assembly.

[0196] An unsealed patient interface 3800, in the form of a nasal cannula, includes nasal prongs 3810a, 3810b which can deliver air to respective nares of the patient 1000 via respective orifices in their tips. Such nasal prongs do not generally form a seal with the inner or outer skin surface of the nares. This type of interface results in one or more gaps that are present in use by design (intentional) but they are typically not fixed in size such that they may vary unpredictably by movement during use. This can present a complex pneumatic variable for a respiratory therapy system when pneumatic control and/or assessment is implemented, unlike other types of mask-based respiratory therapy systems. The air to the nasal prongs may be delivered by one or more air supply lumens 3820a, 3820b that are coupled with the nasal cannula-type unsealed patient interface 3800. The lumens 3820a, 3820b lead from the nasal cannula-type unsealed patient interface 3800 to a respiratory therapy device via an air circuit. The unsealed patient interface 3800 is particularly suitable for delivery of flow therapies, in which the RPT device generates the flow of air at controlled flow rates rather than controlled pressures. The “vent” or gap at the unsealed patient interface 3800, through which excess airflow escapes to ambient, is the passage between the end of the prongs 3810a and 3810b of the nasal cannula-type unsealed patient interface 3800 via the patient’s nares to atmosphere.

[0197] If a patient interface is unable to comfortably deliver a minimum level of positive pressure to the airways, the patient interface may be unsuitable for respiratory pressure therapy.

[0198] The patient interface 3000 in accordance with one form of the present technology is constructed and arranged to be able to provide a supply of air at a positive pressure above the ambient, for example at least 2, 4, 6, 10, or 20 cmH20 with respect to ambient.

5.3.1 Seal-forming structure

[0199] In one form of the present technology, a seal-forming structure 3100 provides a target seal-forming region, and may additionally provide a cushioning function. The target seal-forming region is a region on the seal-forming structure 3100 where sealing may occur. The region where sealing actually occurs- the actual sealing surface- may change within a given treatment session, from day to day, and from patient to patient, depending on a range of factors including for example, where the patient interface was placed on the face, tension in the positioning and stabilising structure and the shape of a patient’s face. [0200] In one form the target seal -forming region is located on an outside surface of the seal-forming structure 3100.

[0201] In certain forms of the present technology, the seal-forming structure 3100 is constructed from a biocompatible material, e.g. silicone rubber.

[0202] A seal-forming structure 3100 in accordance with the present technology may be constructed from a soft, flexible, resilient material such as silicone.

[0203] In certain forms of the present technology, a system is provided comprising more than one a seal-forming structure 3100, each being configured to correspond to a different size and/or shape range. For example the system may comprise one form of a seal-forming structure 3100 suitable for a large sized head, but not a small sized head and another suitable for a small sized head, but not a large sized head.

5.3.1.1 Sealing mechanisms

[0204] In one form, the seal-forming structure includes a sealing flange utilizing a pressure assisted sealing mechanism. In use, the sealing flange can readily respond to a system positive pressure in the interior of the plenum chamber 3200 acting on its underside to urge it into tight sealing engagement with the face. The pressure assisted mechanism may act in conjunction with elastic tension in the positioning and stabilising structure.

[0205] In one form, the seal-forming 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, which 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 spring-like element and functions to support the sealing flange from buckling in use.

[0206] In one form, the seal-forming structure may comprise a compression sealing portion or a gasket sealing portion. In use the compression sealing portion, or the gasket sealing portion is constructed and arranged to be in compression, e.g. as a result of elastic tension in the positioning and stabilising structure.

[0207] In one form, the seal-forming structure comprises a tension portion. In use, the tension portion is held in tension, e.g. by adjacent regions of the sealing flange.

[0208] In one form, the seal-forming structure comprises a region having a tacky or adhesive surface.

[0209] In certain forms of the present technology, a seal-forming structure may comprise one or more of a pressure-assisted sealing flange, a compression sealing portion, a gasket sealing portion, a tension portion, and a portion having a tacky or adhesive surface. [0210] In examples a seal forming structure may comprises a textile component, as described further below.

5.3.1.2 Nose bridge or nose ridge region

[0211] In one form, the non-invasive patient interface 3000 comprises a seal-forming structure that forms a seal in use on a nose bridge region or on a nose -ridge region of the patient's face.

[0212] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal in use on a nose bridge region or on a nose-ridge region of the patient's face.

5.3.1.3 Upper lip region

[0213] In one form, the non-invasive patient interface 3000 comprises a seal-forming structure that forms a seal in use on an upper lip region (that is, the lip superior) of the patient's face.

[0214] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal in use on an upper lip region of the patient's face.

5.3.1.4 Chin-region

[0215] In one form the non-invasive patient interface 3000 comprises a seal-forming structure that forms a seal in use on a chin-region of the patient's face.

[0216] In one form, the seal-forming structure includes a saddle-shaped region constructed to form a seal in use on a chin-region of the patient's face.

5.3.1.5 Forehead region

[0217] In one form, the seal-forming structure that forms a seal in use on a forehead region of the patient's face. In such a form, the plenum chamber may cover the eyes in use.

5.3.1.6 Nasal pillows

[0218] In one form the seal-forming structure 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.

[0219] Nasal pillows in accordance with an aspect of the present technology include: a frusto-cone, at least a portion of which forms a seal on an underside of the patient's nose, a stalk, a flexible 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 technology is connected 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 axially displaced towards the structure to which the stalk is connected. 5.3.1.7 Nose-only Masks

[0220] In one form, the patient interface 3000 comprises a seal-forming structure 3100 configured to seal around an entrance to the patient’s nasal airways but not around the patient’s mouth. The seal-forming structure 3100 may be configured to seal to the patient’s lip superior. The patient interface 3000 may leave the patient’s mouth uncovered. This patient interface 3000 may deliver a supply of air or breathable gas to both nares of patient 1000 and not to the mouth. This type of patient interface may be identified as a nose-only mask.

[0221] One form of nose-only mask according to the present technology is what has traditionally been identified as a “nasal mask”, having a seal-forming structure 3100 configured to seal on the patient’s face around the nose and over the bridge of the nose. A nasal mask may be generally triangular in shape. In one form, the non-invasive patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use to an upper lip region (e.g. the lip superior), to the patient’s nose bridge or at least a portion of the nose ridge above the pronasale, and to the patient's face on each lateral side of the patient’s nose, for example proximate the patient’s nasolabial sulci. The patient interface 3000 shown in Fig. IB has this type of seal-forming structure 3100. This patient interface 3000 may deliver a supply of air or breathable gas to both nares of patient 1000 through a single orifice.

[0222] Another form of nose-only mask may seal around an inferior periphery of the patient’s nose without engaging the user’s nasal ridge. This type of patient interface 3000 may be identified as a “nasal cradle” mask and the seal-forming structure 3100 may be identified as a “nasal cradle cushion”, for example. In one form, for example as shown in Fig. 3Z, the seal-forming structure 3100 is configured to form a seal in use with inferior surfaces of the nose around the nares. The seal-forming structure 3100 may be configured to seal around the patient’s nares at an inferior periphery of the patient’s nose including to an inferior and/or anterior surface of a pronasale region of the patient’s nose and to the patient’s nasal alae. The seal-forming structure 3100 may seal to the patient’s lip superior. The shape of the sealforming structure 3100 may be configured to match or closely follow the underside of the patient’s nose and may not contact a nasal bridge region of the patient’s nose or any portion of the patient’s nose superior to the pronasale. In one form of nasal cradle cushion, the sealforming structure 3100 comprises a bridge portion dividing the opening into two orifices, each of which, in use, supplies air or breathable gas to a respective one of the patient’s nares. The bridge portion may be configured to contact or seal against the patient’s columella in use. Alternatively, the seal-forming structure 3100 may comprise a single opening to provide a flow or air or breathable gas to both of the patient’s nares.

[0223] In some forms, a nose-only mask may comprise nasal pillows, described above. 5.3.1.8 Nose and Mouth Masks

[0224] In one form, the patient interface 3000 comprises a seal-forming structure 3100 configured to seal around an entrance to the patient’s nasal airways and also around the patient’s mouth. The seal-forming structure 3100 may be configured to seal to the patient’s face proximate a chin region. This patient interface 3000 may deliver a supply of air or breathable gas to both nares and to the mouth of patient 1000. This type of patient interface may be identified as a nose and mouth mask.

[0225] One form of nose-and-mouth mask according to the present technology is what has traditionally been identified as a “full-face mask”, having a seal-forming structure 3100 configured to seal on the patient’s face around the nose, below the mouth and over the bridge of the nose. A nose-and-mouth mask may be generally triangular in shape. In one form the patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use to a patient’s chin-region (which may include the patient’s lip inferior and/or a region directly inferior to the lip inferior), to the patient’s nose bridge or at least a portion of the nose ridge superior to the pronasale, and to cheek regions of the patient's face. The patient interface 3000 shown in Fig. 1C is of this type. This patient interface 3000 may deliver a supply of air or breathable gas to both nares and mouth of patient 1000 through a single orifice. This type of seal-forming structure 3100 may be referred to as a “nose-and-mouth cushion”.

[0226] In another form the patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use on a patient’s chin region (which may include the patient’s lip inferior and/or a region directly inferior to the lip inferior), to an inferior and/or an anterior surface of a pronasale portion of the patient’s nose, to the alae of the patient’s nose and to the patient’s face on each lateral side of the patient’s nose, for example proximate the nasolabial sulci. The seal-forming structure 3100 may also form a seal against a patient’s lip superior. A patient interface 3000 having this type of seal-forming structure may have a single opening configured to deliver a flow of air or breathable gas to both nares and mouth of a patient, may have an oral hole configured to provide air or breathable gas to the mouth and a nasal hole configured to provide air or breathable gas to the nares, or may have an oral hole for delivering air to the patient’s mouth and two nasal holes for delivering air to respective nares. This type of patient interface 3000 may have a nasal portion and an oral portion, the nasal portion sealing to the patient’s face at similar locations to a nasal cradle mask.

[0227] In a further form of nose and mouth mask, the patient interface 3000 may comprise a seal-forming structure 3100 having a nasal portion comprising nasal pillows and an oral portion configured to form a seal to the patient’s face around the patient’s mouth. [0228] In some forms, the seal-forming structure 3100 may have a nasal portion that is separate and distinct from an oral portion. In other forms, a seal-forming structure 3100 may form a contiguous seal around the patient’s nose and mouth. [0229] It is to be understood that the above examples of different forms of patient interface 3000 do not constitute an exhaustive list of possible configurations. In some forms a patient interface 3000 may comprise a combination of different features of the above described examples of nose-only and nose and mouth masks.

5.3.2 Plenum chamber

[0230] The plenum chamber 3200 has a perimeter that is shaped to be complementary to the surface 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 seal-forming structure 3100 may extend in use about the entire perimeter of the plenum chamber 3200. In some forms, the plenum chamber 3200 and the seal-forming structure 3100 are formed from a single homogeneous piece of material.

[0231] In certain forms of the present technology, the plenum chamber 3200 does not cover the eyes of the patient in use. In other words, the eyes are outside the pressurised volume defined by the plenum chamber. Such forms tend to be less obtrusive and / or more comfortable for the wearer, which can improve compliance with therapy.

[0232] In certain forms of the present technology, the plenum chamber 3200 is constructed from a transparent material, e.g. a transparent polycarbonate. The use of a transparent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy. The use of a transparent material can aid a clinician to observe how the patient interface is located and functioning.

[0233] In certain forms of the present technology, the plenum chamber 3200 is constructed from a translucent material. The use of a translucent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy.

[0234] In some forms, the plenum chamber 3200 is constructed from a rigid material such as polycarbonate. The rigid material may provide support to the seal-forming structure. [0235] In some forms, the plenum chamber 3200 is constructed from a flexible material (e.g., constructed from a soft, flexible, resilient material like silicone, textile, foam, etc.). For example, in examples then may be formed from a material which has a Young's modulus of 0.4 GPa or lower, for example foam. In some forms of the technology the plenum chamber 3200 may be made from a material having Young's modulus of 0.1 GPa or lower, for example rubber. In other forms of the technology the plenum chamber 3200 may be made from a material having a Young's modulus of 0.7MPa or less, for example between 0.7MPa and 0.3MPa. An example of such a material is silicone.

5.3.2.1 Multiple Openings

[0236] As shown in Figs. 7A and 7B, different plenum chambers 3200-1, 3200-2 may be formed as part of a multi-opening cushion 3050-1, 3050-2. In the illustrated examples, the cushions 3050-1, 3050-2 each include three openings, although an alternate cushion may be formed with greater or fewer openings.

[0237] In some forms, the different openings may serve different functions. For example, some openings may be exclusively inlet openings, while other openings may be exclusively outlet openings.

[0238] In other forms, at least one opening may serve two different functions. For example, one opening may operate as both an inlet and an outlet during the same breathing cycle.

[0239] The plurality of openings may allow for a variety of configurations of air delivery to the plenum chamber 3200-1, 3200-2. For example, depending on patient need and/or patient comfort, the patient may use a given cushion 3050-1, 3050-2 in a “tube-up” configuration (e.g., using conduit headgear - described below) or a “tube-down” configuration (e.g., using a single conduit in front of the patient’s face).

5.3.2.1.1 Nose and Mouth Mask

[0240] As shown in Fig. 7A, the plenum chamber 3200-1 includes a pair of plenum chamber inlet ports 3254-1, which may be used to convey gas into and/or out of the plenum chamber 3200-1. The plenum chamber inlet ports 3254-1 may be disposed on opposite sides (e.g., left and right sides) of the plenum chamber 3200-1.

[0241] In some forms, the plenum chamber 3200-1 may also include at least one vent opening 3402-1 (see e.g., Fig. 7A). The vent opening 3402-1 may be disposed in a center of the plenum chamber 3200-1. For example, the vent opening 3402-1 may be disposed between the plenum chamber inlet ports 3254-1.

[0242] In some forms, the plenum chamber 3200-1 may include a pair of grooves 3266- 1. Each groove 3266-1 may be disposed proximate to one of the plenum chamber inlet ports 3254-1. Each groove 3266-1 may form a partially recessed surface.

5.3.2.1.2 Nose-only Mask

[0243] The plenum chamber 3200-2 of a nasal only cushion 3050-2 may be similar to the plenum chamber 3200-1 of the mouth and nose cushion 3050-1. Only some similarities and differences between the plenum chambers 3200-1, 3200-2 may be described below.

[0244] As shown in Fig. 7B, the plenum chamber 3200-2 includes a pair of plenum chamber inlet ports 3254-2, which may be used to convey gas into and/or out of the plenum chamber 3200-2. The plenum chamber inlet ports 3254-2 may be disposed on opposite sides (e.g., left and right sides) of the plenum chamber 3200-2.

[0245] In some forms, the plenum chamber 3200-2 may also include at least one vent opening 3402-2 (see e.g., Fig. 7B). The vent opening 3402-2 may be disposed in a center of the plenum chamber 3200-2. For example, the vent opening 3402-2 may be disposed between the plenum chamber inlet ports 3254-2. [0246] In some forms, the plenum chamber 3200-2 may include a pair of grooves 3266- 2. Each groove 3266-2 may be disposed proximate to one of the plenum chamber inlet ports 3254-2. Each groove 3266-2 may form a partially recessed surface.

5.3.3 Examples of plenum chamber and seal-forming structure

[0247] One example of the present technology in the form of a patient interface 3000 is shown in Fig. 8 The patient interface comprises a rigid or semi-rigid chassis portion 3202, which forms, at least in part, the plenum chamber 3200, a foam layer 3204, and a textile layer 3206. Collectively, the foam layer 3204 and the textile layer 3206 may form, at least in part, the seal-forming structure of the patient interface 3000. The textile layer may provide the sealing surface, while the foam layer may provide compliance to the seal-forming structure. These respective components will now be discussed in more detail.

[0248] In the illustrated example, the chassis portion 3202 is configured to be used with a patient interface that is configured as an oro-nasal mask. However, the present technology may also be suitable for use with a patient interface configured as a nasal cushion.

[0249] In certain forms of the present technology, the chassis or chassis portion 3202 of the plenum chamber 3200 is constructed from a transparent material. In other forms, the chassis portion may be constructed from a translucent material. The use of a transparent or translucent materials can reduce the obtrusiveness of the patient interface and help improve compliance with therapy. The use of a transparent material can aid a clinician to observe how the patient interface is located and functioning.

[0250] In some forms, the chassis portion 3202 of the plenum chamber 3200 is constructed from a rigid material such as polycarbonate (transparent, translucent or opaque), nylon, co-polyester, a blend of one or more of same, or other suitably rigid plastics material. The rigid material may provide support to the seal-forming structure. Some portions of the chassis portion 3202 may be formed such that some have greater or lesser thickness compared for other parts; for example, the portions of the chassis closest to the patient’s face may have a reduced thickness to confer some slight flexibility for greater comfort for the patient. Portions of the chassis portion which are further away from the face, and more central, may be thicker to better control the extent of flexure of these areas. The thickness of the rigid material may range from between 0.5 mm to 3 mm, although strict compliance with this range is not required.

[0251] In some forms, the chassis portion 3202 of the plenum chamber 3200 may be constructed from a semi-rigid material; this may be desired in order to provide some flexibility to the chassis. Suitable materials may include the likes of liquid silicone rubber or a thermoplastic elastomer. To provide some rigidity, and thus greater support for the sealforming structure, the chassis may be configured to receive a frame composed of a rigid material such as polycarbonate (transparent, translucent or opaque), nylon, co-polyester, a blend of one or more of same, or other suitably rigid plastic materials.

[0252] Referring to Figs. 9A and 9B, it will be seen that the chassis portion 3202 is configured such that is cup- or bowl-shaped in profile, the interior or posterior side of the chassis defining an air chamber 3203 of the patient interface (not shown in Figs. 9A and 9B). The anterior side 3205a of the anterior wall 3205 of the chassis portion 3202 defines the exterior surface of the plenum chamber.

[0253] In use, the air chamber 3203 receives the nose and mouth of the patient and it will be understood that the chassis portion 3202 will be dimensioned accordingly to ensure clearance about the nose and mouth of the patient in use. The chassis portion may be provided in a range of sizes; for example, its width, height, and depth may be arranged into small, mid, large, and extra-large embodiments to cater for different face sizes and shapes.

[0254] Centrally located to the chassis portion 3202 is an aperture 3207 configured to receive a decoupling structure (3600 in Fig. 3A) or the end of the air circuit (4170 in Figs. 1A to 1C). However, in other examples, particularly those configured for use with conduit headgear, apertures may provided to one or both sides of the chassis, rather than centrally, as per the example illustrated here. In these other examples, the apertures may be configured with connectors or structures that in use receive the inferior ends of the tubes comprising the conduit headgear.

[0255] The chassis portion 3202 is comprises or is provided with a flange 3208 about a portion of its perimeter. As illustrated, this flange extends in a plane inward towards the air chamber 3203. This is preferred as it helps minimise the overall footprint of the plenum chamber on the patient’s face. However, in some examples not shown here, the flange may also extend, either wholly or partially, away from the air chamber. This may mean the entire flange is positioned exterior to the air chamber or alternatively, an outer portion of the flange is exterior of the air chamber and an inner portion extends inward towards the air chamber. [0256] In the illustrated example, the flange 3208 is provided in regions that substantially correspond to the sides of the patient’s mouth, the patient’s cheeks, and to the sides of the patient’s nose, when the patient interface is in use. In the illustrated example, the width of the flange 3208 is substantially constant about the perimeter of the chassis portion 3202. In some examples, the width of the flange may be as little as 5 mm but in others, it could be 10 mm or more. Variances to these dimensions are envisaged. In other examples, there may be reductions or increases in the width of the flange for comfort and increased contact, and therefore sealing functionality; in these examples, the width of the flange may from between 5 mm to 10 mm, or lesser or greater if preferred.

[0257] In use, the posterior side of the flange receives and supports at least part of the seal-forming structure in the form of the foam layer referred to above, as shown in Fig. 10. Upon loading being applied to the patient interface, for example through the force exerted by the positioning and stabilising structure 3300 of Fig. 3A, as discussed further later in this specification, the foam layer is compressed or otherwise deforms.

[0258] The foam layer 3204 is to provide the bulk of the seal-forming structure, i.e. supports the textile layer 3206 that seals against the patient’s face when wearing the patient interface. The use of a foam layer helps with conformity to the shape and contours of the patient’s face. The foam layer 3204 has an inner perimeter 3204A and an outer perimeter 3204B.

[0259] In the illustrated example, the foam layer 3204 may be comprised of an open cell memory foam or the like, such as rubber, urethane, polyurethane, a blend thereof or another suitable material. The foam layer 3204 may be cut from a sheet of the material of choice, which is provided in a uniform thickness ranging from 5mm to 25mm, although strict compliance with this range is not essential. It will be understood in this example that the thickness determines the relative depth of the foam layer and therefore its compressibility. The thickness of the sheet from which the foam layer is cut may ultimately depend on the desired conformity compliance with the face of the patient; the thicker the sheet, the superior the conformity to the face. Conversely, the thinner the sheet, the ability to conform to the face may be somewhat compromised. In some examples, the sheet of material may be configured with varying thicknesses across is cross-sectional profile; i.e. the sheet of material has a non- uniform thickness. When cutting the sheet of material to form the foam layer, this may mean that portions of the foam layer are of greater thickness than other portions. For example, the portion of the foam layer corresponding to the lower lip/chin region of the patient’s face may be thicker than the portion corresponding to the patient’s cheeks.

[0260] The foam layer 3204 of Fig. 10 is an unitary, one-piece component. In other examples not shown here, the foam layer may be comprised or two of more individual components which are bonded or otherwise secured to the flange. In one such example, the foam layer may be provided as two mirror halves.

[0261] In another example, not shown here, the foam layer 3204 may be configured to have a specific cross-sectional profile, for example, a C-shaped profile, that is intended to compress readily as required. In these examples, the foam layer may be not be formed from a sheet of material but is instead in the form of a moulding of a suitable elastomer material having an appropriate Shore rating; for example, of 30 to 50 Shore A range.

[0262] In one example, the foam layer 3204 may be bonded with a suitable adhesive or otherwise secured to the flange. In other examples, and depending on the material used for the foam layer, it may be overmoulded to the flange 3208.

[0263] When bonded or otherwise secured to the flange 3208, the respective outer sides of the foam layer 3204 are substantially flush with (e.g. coextensive with) the outer edge of the flange. As such, the foam layer 3204 does not materially add to the overall footprint of the plenum chamber on the patient’s face. However, in examples where the flange 3208 may extend, partially at least, to the exterior of the chassis portion 3202, the foam layer 3204 may be flush with the outer edge of the flange.

[0264] In examples, the width of the foam layer ranges from 10 mm to 20 mm, although variances to this are envisaged. It will be seen that the width dimension of the flange 3208 is less than that of the foam layer 3204, as shown in Figs. 11 A and 1 IB. In the illustrated example, the width of the flange is substantially half that of the foam layer; thus about half of the foam layer is supported and half is unsupported. However, in other examples, the width of the flange may be a little more, or less, depending on the patient’s preference, therefore increasing or decreasing the amount of support to the foam layer.

[0265] In use, as a force is applied to the plenum chamber 3200, such as is exerted by the positioning and stabilising structure 3300 of Fig. 3A, this compresses and causes some rotation of the foam layer into the air chamber 3203 relative to the flange 3208. This rotation helps with providing an adequate seal about the patient’s face, particularly the angular surfaces, such as the side of the nose, when in use. The extent of the rotation of the foam layer may be controlled by the relative width of the flange. Where there is greater curvature of the patient’s face, for example the sides of the nose, the width of the flange may be reduced relative to the width of the corresponding portion of the foam layer. This may provide greater rotation of the foam layer and therefore sealing across the curvature of the patient’s nose. Conversely, where the patient’s face is relatively flat, such as the cheeks, little rotation of the foam layer may be required so the flange may have a greater width, relative to width of the corresponding portion of the foam layer. In some examples, the width of the flange may be substantially the same as the width of the foam layer.

[0266] Although not shown in Figs. 11 A and 1 IB, in some examples, the corners of the cross-sectional profile of the foam layer 3204 may be rounded to assist with providing a sealing surface with the patient’s face. In an example, the rounding may have a radius of between 1 mm to 10 mm. The rounding of the corners may not be uniform along the length of the foam layer. In one example, the rounding of the corners of the foam layer at the portion corresponding to the patient’s nose may be greater than that corresponding to the patient’s cheeks (or vice versa). This may be useful in increasing or decreasing the contact surfaces of the seal-forming structure with the patient’s face.

[0267] Returning to Figs. 9A and 9B, it will be seen that the chassis portion 3202 includes openings or cutouts 3209 on its upper or superior side and openings or cutouts 3260 on its lower or inferior side (these shall now be referred to as superior opening and inferior opening respectively). The presence of the superior and inferior openings 3209, 3260 provide clearance for the nose bridge and chin/lip inferior/supramenton of the patient’s face respectively, both of these portions of the face being relatively sensitive. In another example, not shown here, when the plenum chamber is intended for use as a nasal mask, the inferior opening may provide clearance for the lip superior. The removal of a rigid portion of the chassis portion 3202 in these areas may improve patient comfort. Because of the presence of these openings, the flange is also absent in these regions of the chassis.

[0268] In Fig. 10, it will be seen that the foam layer 3204 spans the flange (obscured in this view) proximate the inferior opening 3210. This still leaves an opening on the anterior side of the chassis portion 3202 corresponding to the inferior opening which in use will need to be covered to ensure sealing functionality. Similarly, the corresponding superior opening also needs to be covered in use. As can be seen, the foam layer terminates at ends 3204C and as such does not span the superior opening; instead a gap is left which, during use, receives the nose bridge region of the patient’s face. The relative width of the gap may vary; for example, when the plenum chamber is provided in small, medium and large sizes, the relative width may increase in incremental steps to accommodate greater widths of the nose bridge region.

[0269] Turning Figs. 12A to 12D, it will be seen that the textile layer 3206 is configured such that in use, the respective superior and inferior openings of the chassis are covered by superior and inferior portions 3206A and 3206B respectively of the textile later. It will be understood that, the textile layer 3206 has an anterior side and posterior side; in use, the latter side contacts the patient’s face and such, forms the target seal-forming region. The former side serves as the surface which is bonded to the foam layer 3204.

[0270] In one example, the textile layer 3206 is cut from a sheet of textile material that is impermeable to air. It is particularly desirable that the textile material be relatively elastic, such that it can be stretched. In one example, this textile material may be a blend of nylon and spandex although it will be appreciated the textile material may be comprised of other materials, for example, a blend of synthetic materials derived from a polymer, or may also include or alternatively comprise some natural textiles, such as cotton or the like. The latter may be helpful for patients with allergies to synthetic materials. The anterior side of the textile layer 3206 is coated with a sheet or layer of a material such as silicone rubber or similar material. This helps with ensuring the textile layer is impermeable to air. In some examples, to further ensure the textile is impermeable to air, or to provide patient comfort, the posterior side of the textile layer may also be provided with a coating of silicone rubber or the like.

[0271] In Fig. 12A it will be seen that the textile layer 3206 has been cut from a single piece of material such that it is a unitary component. However, in another example, such as that shown in Fig. 8, the textile layer 3206 may be provided as two distinct and separate components; the main portion 3206 which includes an integral superior portion 3206A with the inferior portion 3206B being separate. In a further example, not shown here, the portion 3206A for the superior opening may be provided as a separate component while the portion 3206B for the inferior opening of the chassis portion 3202 is integral to the textile layer 3206. In yet a further example, not shown, both portions 3206A and 3206B may be provided separately to the textile layer 3206. Having one or both of the superior 3206A and inferior 3206B portions as separate components can be useful for providing options for customisation. For example, one or both of the superior portion 3206A and inferior portion 3206B may not be fully impermeable, allowing a degree of airflow in and out of the patient interface; this may assist in cooling. In other examples, the superior portion 3206A may be comprised of a silicone member for patients that prefer contact with this type of material for the skin about the nose bridge.

[0272] The textile layer 3206 has an outer perimeter 3211 and an inner perimeter 3212. The cutting of the textile layer 3206 is such that it has a shape with a substantial portion of its outer perimeter 3211 corresponding to the outer perimeter of the foam layer 3204, except for superior and inferior portions 3206 A and 3206B. As such, aside from the exceptions noted, the outer perimeter 3211 of the textile layer 3206 is substantially flush with the outer perimeter of the foam layer 3204. However, in some examples, the outer perimeter 3211 may be dimensioned such that it is able to be folded over the outer edge of the foam layer 3204 and bonded to the side surfaces of same. This may provide for a more aesthetically pleasing finish. In such examples, the junctures of the superior and inferior portions 3206A and 3206B juncture with the outer perimeter 3211 of the textile layer 3206 may need to be appropriately cut or otherwise configured to facilitate a smooth transition in these areas of the textile layer. [0273] Returning to the illustrated example, the width of the textile layer 3206 between the outer perimeter 3211 and the inner perimeter 3212 is dimensioned to slightly exceed the width of the foam layer. This provides the textile layer 3206 with a slight overhang 3213 at the inner perimeter 3212. In use, this overhang 3213 covers the inner corners of the foam layer 3204 and helps ensure that only the textile layer is in contact with the patient’s face. The extent of the overhang 3213 may vary; for example, where the greatest rotation of the foam layer 3204 may occur, such as at the sides of the nose of the patient, the overhang may be greater than that corresponding to the portion of the foam layer that may experience relatively minimal rotation, such as at the cheeks of the patient. Increasing the extent of the overhang may also provide a softer feel, by virtue of the loose material at the edge of the textile layer, against the patient’s skin when wearing the patient interface.

[0274] The textile layer 3206 is bonded to the foam layer 3204 using an appropriate adhesive applied to the anterior side of same, as shown in Fig. 13, which depicts the foam layer 3204 affixed to the flange 3208 . As can be seen, the outer perimeter 3211 of the textile layer 3206 is bonded to the foam layer 3204 at the outer corner of same, using a bead of adhesive 3214 or other bonding agent. This leaves the majority of the textile layer, including the overhang 3213, unsecured which may be beneficial in forming a seal with the patient’s face. In the event of a change in the forces being applied to the seal-forming structure, for example by the positioning and stabilising structure or in the event of the patient interface contacting bedding or the like and being slightly moved on the patient’s face, pressurised air flowing into the air chamber 3203 penetrates between the unsecured portion of the textile layer, urging it against the patient’s face, maintaining or restoring sealing contact. However, in some portions, the adhesive or bonding agent may not be limited to the outer corner of the foam layer and instead may extend partially, or fully, across the width of the foam layer. For the latter, this can help minimise the effect of any blow out of pressurised air if the patient interface is rearranged on the face of the wearer.

[0275] At the portions of the foam layer 3204 adjacent to the superior opening 3209 of the chassis portion 3202 (i.e. the ends 3204C of Fig. 10) the adhesive or other bonding agent may extend at least partially across the width dimension of the foam layer, i.e. follow the line of the outer perimeter 3204B of the foam layer until close to, or even meeting, the inner perimeter 3204A of the foam layer. This may improve sealing conformity in this region of the patient interface, minimising the potential for any seal blow out. Given the proximity of the nasal bridge, it will be appreciated that any such blow out may be into the patient’s eyes, and as such quite undesirable.

[0276] As noted previously, the superior portion 3206 A of the textile layer 3206 is intended to close off and seal the superior opening 3209 provided to the chassis portion 3202. This is achieved by folding the superior portion 3206A back over the anterior/exterior side 3205a of the chassis portion 3202. As such, the anterior side of the superior portion 3206A now forms a portion of the posterior side of the air chamber, while the posterior side of portion 3206 now faces outwards, away from the patient’s face, and forms part of the exterior surface 3205a of the chassis portion 3202 as best seen in Fig. 14. The perimeter of the anterior side of the superior portion 3206A is secured to the perimeter of the superior opening 3209 through the use of a suitable bonding agent or adhesive. In other examples, the chassis portion 3202 may be configured to receive an insert about the perimeter of the superior opening, which secures the superior portion 3206A in place in a snaplock or friction fit arrangement. In other examples, ultrasound welding techniques may be used to secure the superior portion 3206 A to the exterior side 3205 a of the plenum chamber.

[0277] Although the superior opening 3209 is covered, it is unsupported, by virtue of the absence of the underlying chassis portion 3202 in this region. Referring to Fig. 12C in particular, it will be seen that the curvature of the superior portion 3206A of the textile layer 3206 across the superior opening 3209 has a smaller radius that the curvature of the textile layer across the foam layer 3204. When a patient is wearing the patient interface incorporating the depicted plenum chamber 3200, the superior portion 3206A of the textile layer 3206 is stretched across their nose bridge, applying tension to same and forming the sealing contact in this region of the face. However, the absence of the chassis portion 3202 and the foam layer 3204 in this region means that the tensile force is kept relatively low. This may provide greater comfort for in the nose bridge region, due to the absence of a compressive force. Instead, the compressive force is confined to those portions of the patient’s face corresponding to the presence of the foam layer. Collectively the tensile force and the compressive force establishes the seal about the airways of the patient. The extent of the tensile force may be adjusted if desired, by configuring the superior opening and foam layer such the gap in the chassis at this point is wider or narrower as the case may. Similarly, this may also allow for deeper and shallower nose bridges.

[0278] Where applicable, similar considerations apply to the inferior portion 3206B of the textile layer 3206 that covers the inferior opening 3260of the chassis portion 3202. This is best seen in Fig. 12D. However, it should be noted that due to the presence of the foam layer spanning the inferior opening, the inferior portion 3206B does not contact the face. In the illustrated example, the inferior portion 3206B is folded over the outer perimeter of the foam layer and the exterior surface 3205a of the chassis surrounding the inferior opening 3260. It can then be secured in place with an appropriate adhesive or other bonding agent, applied to the surfaces of the foam layer and chassis that it contacts. The inferior portion 3206B may alternatively be subject to ultrasonic welding techniques to secure it in place or a separate fitting used to fix it in place in a snaplock or friction fit arrangement.

[0279] However, in examples where the inferior portion 3206B is a separate component, such as shown in Fig. 8, this may be secured in place directly to the portion of the chassis surrounding the inferior opening and also to the adjacent foam layer, through application of adhesive or other bonding agent, ultrasonic welding techniques or mechanical methods. [0280] When the inferior portion 3206B is provided as a separate component, this provides some ability to customise the relative rigidity of the overall plenum chamber 3200 in the region corresponding to the chin (or, for nasal masks, the upper lip). For example, the textile material used to form the inferior portion 3206B may be more rigid, or thicker, than that used for the remainder of the textile layer. This approach may help improve the performance of the seal-forming structure in this region of the plenum chamber.

[0281] Referring next to Figs. 15A-21, in another form of the technology the foam layer may not be required.

[0282] The chassis portion 3202 of the example in Figs. 15A-16C has a superior cutout or opening 3209, similar to that of the previously described example, but does not have a corresponding inferior opening or cutout 3260 (although in other examples an inferior opening 3260 may be provided). In some examples the chassis portion may comprise a thinned area (for example of thickness of between 0.3 mm-0.6 mm) in substantially the same position as the inferior cutout described above, in order to provide additional compliance in this area. In examples, the portion 3209a of the superior cutout 3209 in the anterior wall 3205 of the chassis may have a substantially triangular or inverted teardrop shape, as shown in Fig. 16 A.

[0283] In one form of the technology the chassis portion 3202 may be relatively flexible. The chassis portion 3202 may be formed from an elastomer, for example silicone. In one example the chassis portion 3202 material may have a Shore A Durometer hardness of between 30 and 60.

[0284] The chassis portion 3202 may have a configuration which allows the direct connection of a tubing component, for example an air conduit 4170, to supply pressurised air to the plenum chamber 3200 (e.g. via plenum chamber inlet port 3254). In examples the chassis portion 3202 may be configured for connection to a frame component (not shown). In some examples having a frame component, the frame component may operate as an intermediary between the air circuit 4170 and the plenum chamber 3200. The patient interface may be configured in a “tube up” or “tube down” configuration, as described herein.

[0285] The chassis portion 3202 of the example shown in Figs. 15A-16C may comprise a flange 3208, for example a flange which extends inwardly toward the breathing chamber (see Figs. 16B and 19). A textile layer 3206, similar to that described above, maybe provided to the flange 3208, as is described further below.

[0286] Referring next to Figs. 16A-16C in particular, the superior edges 3208a of the flange 3208 may be inferior to the nose bridge and the front of the nose of the patient. The flange 3208 may comprise sides of nose portions 3208b which are configured to engage the sides of the patient’s nose, in use. In examples, the sides of nose portions 3208b engage the nose at areas corresponding to the nasal bone (as opposed to cartilaginous portions of the nose) and provide a compliant sealing force. In examples, the sides of nose portions 3208b are configured to substantially avoid engagement of the sides of the patient’s nose corresponding to the patient’s greater alar cartilage and/or septum cartilage in order to prevent occlusion of the nose.

[0287] The chassis portion 3202 may hold the textile layer 3206 in place around the cheek and chin areas and may provide a level of compliance through bending of the main body of the chassis portion 3202 and/or the flange 3208. In one example the chassis portion 3202 may have a Shore A durometer of approximately 40, and may, for example, be made from LSR (Liquid Silicone Rubber).

[0288] Referring next to Fig. 19 in particular, in one example the flange 3208 is curved inwardly, for example to form a substantially “C” shaped in profile. In examples, the curvature of the flange 3208 is substantially continuous with the curvature of the immediately adjacent portion of the chassis portion 3202 (in contrast to the examples shown in Figs 8-14, where the flange 3208 is more sharply curved or bent inward). In examples, the flange 3208 has a thickness between 2.5mm and 0.5mm. The thickness of the flange 3208 where the textile 3206 is mounted to the flange 3208 may be between 0.5mm- 1.5mm in examples. In examples the thickness of the flange 3208 may taper towards its free edge 3208c.

[0289] As best seen in Fig, 15F, the chassis portion 3202 may have a very low profile in the region near the patient’s nose. This configuration may avoid causing discomfort to the patient because the area over the patient’s nose is formed by the textile layer 3206 which spans the superior cutout 3209. Even if the patient’s nose temporarily contacts the portion of the textile which spans the portion of the superior opening 3209 in the anterior wall 3205 of the chassis portion 3202, the patient will not feel significant discomfort since the textile layer 3206 is flexible, as is described further below. If the superior opening or cutout 3209 was not present, it would be necessary for the anterior wall 3205 of the chassis portion 3202 to be spaced further from the patient’s nose.

[0290] In some examples, the superior cutout 3209 may not extend to the anterior wall 3205 of the chassis portion 3202. Such examples may improve visibility and/or make mould tooling more efficient. Examples where the cutout 3209 does not extend to the anterior wall 3205 of the chassis portion 3202 may need to be configured to provide additional clearance between the chassis portion 3202 and the patient’s nose, since contact of the patient’s nose with the rigid or semi-rigid material of the anterior wall 3205 of the chassis portion 3202 may be unacceptably uncomfortable.

[0291] The textile layer 3206 may be connected to the flange 3208, and may form the contact/sealing region with the patient’s face.

[0292] Fig. 17 shows an example of the textile layer 3206 in a flat configuration, for example immediately after cutting from a bulk piece of material (not shown), e.g. prior to connection to the flange 3208. In examples, the entire textile layer 3206 may be cut as one piece from a flat (e.g. not 3D formed) sheet of textile, for example die cut. However, in other examples the textile layer 3206 may comprise a plurality of separate components.

[0293] The textile layer 3206 may comprise a stretchable material, for example a woven Nylon/Elastane blend material. In examples, the material may be coated with a thin silicone coating to make it air impermeable. In other embodiments the textile layer 3206 may be configured such that a small amount of air is permitted to pass through the textile layer 3206 (over the entire textile layer, or in selected regions) to cool the patient’s skin.

[0294] In examples, the textile layer 3206 is airtight and stretchable. The ability of the textile to stretch may reduce the tension across the nose bridge area and enables the cushion to fit a larger range of nose bridge shapes. In some examples the textile layer 3206 may be undermoulded by a very thin (e.g. <0.4mm) layer of elastomer for added support, or if the textile used is not independently air tight.

[0295] In examples the main portion 3206d of the textile layer 3206 is shaped to form the face contact area around the mouth and cheeks. The superior portion 3206a is folded over the anterior of the chassis portion 3202 to close off and seal the superior cutout 3209 in the chassis portion 3202, in a similar manner to the example described above with reference to Figs. 8 - 14.

[0296] Referring next to Figs.l5B, 15E and 15G in particular, the connection between the textile layer 3206 and the chassis portion 3202 and flange 3208 causes the textile layer 3206 to form a concave region 3215 which is configured to fit around the patient’s nose bridge. In one example the concave shape formed by the textile layer 3206 may have a width of between 8 mm and 20 mm (e.g. around 10 mm) and a depth between 5 mm and 20 mm (e.g. around 10 mm).

[0297] The width and depth of the concave region 3215 may be controlled by the shape of the textile layer 3206, when cut. The textile layer 3206 may be configured with a neck portion 3206c between the main portion 3206d of the textile layer 3206 and the superior portion 3206a, the neck portion 3206c having a reduced width relative to the maximum width of the superior portion 3206a and the main portion 3206d. Providing a wider neck portion 3206c may result in a deeper concavity when the textile layer 3206 is connected to the chassis portion 3202.

[0298] The width of the neck portion 3206c may also be configured to reduce creasing of the textile layer in use. Excessive width at the neck 3206c may increase the likelihood of creasing, although the dimensions of the textile layer 3206 will be dependent on the shape and dimensions of the chassis portion 3202, flange 3208 and the superior opening/cutout 3209. Textile layers which are relatively less stretchable may be less likely to suffer from creasing in this area.

[0299] Areas in which the textile layer 3206 is not supported by a flange 3208 (e.g. where the textile layer 3206 spans the cutout 3209) may provide areas of increased stretch and softness, compared to areas in which the flange 3208 is present. Such areas may be used to reduce direct load and shear load on the sensitive area of the nose bridge, where the thin skin and lack of underlying soft tissue is at risk of comfort issues and skin breakdown issues.

[0300] In some forms of the technology the textile layer 3206 extends around the entire periphery of flange 3208. However, in other examples the textile layer 3206 may be shaped such that it does not contact the patient's face in one or more areas, for example the chin, cheeks and/or sides of the nose. Fig. 18 shows an example where a chin portion 3216 is absent from the textile layer 3206. In such areas the flange 3208 may be configured as a sealing portion. This may be desirable, for example, to provide areas of higher friction which may assist with sealing and/or preventing the patient interface from slipping on the face.

[0301] In examples, the textile layer 3206 is connected to the chassis portion 3202 by inserting the textile layer 3206 into a mould and then forming the chassis portion 3202 (including the flange 3208) around the textile layer 3206. In such examples, the textile layer 3206 may be connected to the flange 3208 across the entire width of the flange. However, in other examples only the outer perimeter of the textile layer 3206 is bonded to the flange 3208, e.g. using a bead of adhesive.

[0302] In examples (see Fig. 19), textile layer 3206 is configured to extend beyond the free edge 3208c of the flange 3208 such that a portion 3218 of the textile layer 3206 is unsupported. This may provide a soft edge which reduces the risk of skin irritation, and may also assist in the moulding process by providing an area for the moulding tool to clamp onto the textile.

[0303] In examples, the unsupported textile portion 3218 may be around 2 mm wide. However, this may be varied. While some examples may have an unsupported portion 3218 having a substantially uniform width around the perimeter of the flange, in examples the width of the unsupported portion may vary around the perimeter of the flange.

[0304] In some forms of the technology there may be substantially no unsupported portion of the textile layer 3206 around at least some, or possibly all, of the perimeter of the flange.

[0305] In another form of the technology, shown in Figs 20A-20C, the chassis portion 3202 may not be made from a single material. Instead, a shell portion 3270 formed from a more rigid material, for example a polycarbonate, may be used to form at least a part, for example a central portion 3222, of the anterior wall 3205 of the chassis portion 3202. A more flexible material (for example an elastomer as described above) may be provided around at least a portion of the outer edge of the shell portion 3270. In examples, the more flexible material extends around substantially the entire outer edge of the shell 3270, apart from areas (if any) where the superior opening or cutout 3209 extends into the shell 3270.

[0306] The more flexible chassis portion material may be provided with a flange 3208 for mounting the textile layer 3206, as described above. In examples, the lateral and inferior walls of the plenum chamber 3200 are formed from the more flexible material (that is, in examples, the shell portion 3270 does not extend to these portions of the chassis portion).

[0307] The more flexible material may be overmoulded to the shell portion 3270. The shell portion 3270 may comprise features around its edge to assist with connection to the more flexible material.

[0308] Providing a shell portion 3270 may reduce the amount of more flexible material (e.g. elastomer) required to create the patient interface, which may result in weight and costs savings. It may also provide more support to the lateral and inferior walls of the plenum chamber 3200, and may provide greater control of the deformed shape of those walls when the patient interface is in use. In examples, the shell portion 3270 may comprise tube connection geometry and/or frame connection geometry.

[0309] Referring in particular to Fig. 20A, a portion of the textile layer 3206 may be connected directly to the shell portion 3270 (e.g. where the cutout 3209 protrudes into the shell portion 3270). This attachment may be through welding or through a mechanical connection, e.g. a snap retention.

[0310] Referring next to Fig. 21, in other examples the anterior wall 3205 may be formed from a relatively flexible material (e.g. silicone) with a shell portion 3270 of more rigid material connected to an outer surface thereof in order to provide support. The shell portion 3270 may be connected by an adhesive or a mechanical fastener, or the more flexible material may be moulded with the shell 3220.

[0311] The shell material may be more rigid than the remainder of the chassis material, but may still be only semi-rigid, to allow a small but functionally significant amount of flexibility. In examples, the shell material may be a nylon, a polyester or a semi-rigid elastomer such as TPE or silicone having a Shore A hardness of >60.

5.3.4 Positioning and stabilising structure

[0312] 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. The positioning and stabilising structure 3300 may comprise and function as “headgear” since it engages the patient’s head in order to hold the patient interface 3000 in a sealing position. Examples of a positioning and stabilising structure may be shown in Figs. 3 A and 3A-1.

[0313] In one form the positioning and stabilising structure 3300 provides a retention force at least sufficient to overcome the effect of the positive pressure in the plenum chamber 3200 to lift off the face (i.e., F_pienum).

[0314] In one form the positioning and stabilising structure 3300 provides a retention force to overcome the effect of the gravitational force on the patient interface 3000.

[0315] With continued reference to Fig. 3A-1, the positioning and stabilising structure 3300 provides a force FPSS that assists in maintaining the plenum chamber 3200 in the sealing position on the patient’s face. The positioning and stabilising force FPSS may be the resultant force from the various forces of the different elements of the positioning and stabilising structure 3300. For example, headgear straps may individually provide a strap force F_strap in order to hold the seal-forming structure 3100 against the patient’s face. The force F_strap may also be directed at least partially in the superior direction in order to overcome the gravitational force F_g. The gravitational force F_g may be specifically shown for the seal- forming structure 3100 and the plenum chamber 3200, but gravity would act on the entirely of the patient interface 3000 (i.e., in the same direction as the illustrated gravitational force F_g). [0316] The gravitational force F_g may be opposed by a frictional force Ff, which may act in a direction directly opposite of the gravitational force F_g. As gravity pulls the seal-forming structure 3100 and the plenum chamber 3200 in the inferior direction (as viewed in Fig. 3A- 1), the frictional force Ff would act in the superior direction (e.g., against a patient’s face). For example, the patient may experience the frictional force Ff against his lip superior (and/or other surfaces of the patient’s face in contact with the seal-forming structure 3100) in order to oppose the motion in the inferior direction (which may help to stabilising the cushion in place). Although the frictional force Ff is shown specifically opposing the gravitational force F_g of the seal-forming structure 3100 and the plenum chamber 3200, components of an overall frictional force (not shown) would also oppose the gravitational force F_g associated with the positioning and stabilising structure 3300 and any other portions of the patient interface 3000. A force of friction can act along any place where the patient interface 3000 contacts the patient’s skin (or hair). The frictional force Ff extends in the opposite direction of the gravitational force F_g and along the patient’s skin (or hair). In some forms the gravitiational force F_g may also be countered by vertical components of the reaction force from the patient’s face acting on the seal-forming structure 3100, for example at the nose ridge and chin regions of the patient’s face, for example.

[0317] In some forms, the sum of the various forces may equal zero so that the patient interface 3000 is at equilibrium (e.g., not moving along the patient’s face while in use). Specifically, the gravitational force F_g and the blowout force F_pienum tend to move the sealforming structure 3100 away from the desired sealing position. The positioning and stabilising force FPSS is applied in order to counteract the gravitational force F_g and the blowout force F_pienum (as well as any frictional forces Ff) and keep the seal-forming structure 3100 properly situated. Although the positioning and stabilising force FPSS may exceed the sum of the gravitational force F_g and the blowout force F_pienum (with any additional positioning and stabilising force FPSS being balanced by reaction force from the patient’s head acting on the portions of patient interface 3000) and still maintain the seal-forming structure 3100 in an appropriate sealing position, patient comfort may be sacrificed. Maximum patient comfort may be achieved when the net force on the patient interface 3000 is zero and the positioning and stabilising force FPSS is exactly strong enough to achieve this. In some examples the positioning and stabilising structure 3300 may be adjustable such that when fitted the positioning and stabilising force FPSS is greater than required to exactly balance the gravitational force F_g and the blowout force F_pienum to hold the patient interface 3000 against the patient’s head tightly enough that disruptive forces which may be experienced in use (such as tube drag or lateral shunting of the plenum chamber 3200 during side sleeping) do not disrupt the seal. As described below, various positions of the patient’s head while using the patient interface 3000 may determine the positioning and stabilising force FPSS necessary to achieve equilibrium.

[0318] In one form the positioning and stabilising structure 3300 provides a retention force as a safety margin to overcome the potential effect of disrupting forces on the patient interface 3000, such as from tube drag, or accidental interference with the patient interface. [0319] In one form of the present technology, a positioning and stabilising structure 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 perceived 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.

[0320] In one form of the present technology, a positioning and stabilising structure 3300 is provided that is configured so as not to be too large and bulky to prevent the patient from lying in a supine sleeping position with a back region of the patient’s head on a pillow. [0321] In one form of the present technology, a positioning and stabilising structure 3300 is provided that is configured so as not to be too large and bulky to prevent the patient from lying in a side sleeping position with a side region of the patient’s head on a pillow. [0322] In one form of the present technology, a positioning and stabilising structure 3300 is provided with a decoupling portion located between an anterior portion of the positioning and stabilising structure 3300, and a posterior portion of the positioning and stabilising structure 3300. The decoupling portion does not resist compression and may be, e.g. a flexible or floppy strap. The decoupling portion is constructed and arranged so that when the patient lies with their head on a pillow, the presence of the decoupling portion prevents a force on the posterior portion from being transmitted along the positioning and stabilising structure 3300 and disrupting the seal.

[0323] In one form of the present technology, a positioning and stabilising structure 3300 comprises a strap constructed from a laminate of a fabric patient-contacting 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.

[0324] 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 seal-forming structure into sealing contact with a portion of a patient’s face. In an example the strap may be configured as a tie. [0325] In one form of the present technology, the positioning and stabilising structure comprises a first tie, the first tie being constructed and arranged so that in use at least a portion of an inferior edge thereof passes superior to an otobasion superior of the patient’s head and overlays a portion of a parietal bone without overlaying the occipital bone.

[0326] In one form of the present technology suitable for a nasal-only mask or for a fullface mask, the positioning and stabilising structure includes a second tie, the second tie being constructed and arranged so that in use at least a portion of a superior edge thereof passes inferior to an otobasion inferior of the patient’s head and overlays or lies inferior to the occipital bone of the patient’s head.

[0327] In one form of the present technology suitable for a nasal-only mask or for a fullface mask, the positioning and stabilising structure includes a third tie that is constructed and arranged to interconnect the first tie and the second tie to reduce a tendency of the first tie and the second tie to move apart from one another.

[0328] In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap that is bendable and e.g. non-rigid. An advantage of this aspect is that the strap is more comfortable for a patient to lie upon while the patient is sleeping.

[0329] In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap constructed to be breathable to allow moisture vapour to be transmitted through the strap,

[0330] In certain forms of the present technology, a system is provided comprising more than one positioning and stabilising structure 3300, each being configured to provide a retaining force to correspond to a different size and/or shape range. For example the system may comprise one form of positioning and stabilising structure 3300 suitable for a large sized head, but not a small sized head, and another, suitable for a small sized head, but not a large sized head.

5.3.4.1 Conduit headgear

5.3.4.1.1 Conduit headgear tubes

[0331] In some forms of the present technology, the positioning and stabilising structure 3300 comprises one or more headgear tubes 3350 that deliver pressurised air received from a conduit forming part of the air circuit 4170 from the RPT device to the patient’s airways, for example through the plenum chamber 3200 and seal-forming structure 3100. In the form of the present technology illustrated in Fig. 3Z, the positioning and stabilising structure 3300 comprises two tubes 3350 that deliver air to the plenum chamber 3200 from the air circuit 4170. The tubes 3350 are configured to position and stabilise the seal-forming structure 3100 of the patient interface 3000 at the appropriate part of the patient’s face (for example, the nose and/or mouth) in use. This allows the conduit of air circuit 4170 providing the flow of pressurised air to connect to a connection port 3600 of the patient interface in a position other than in front of the patient’s face, for example on top of the patient’s head.

[0332] In the form of the present technology illustrated in Fig. 3Z, the positioning and stabilising structure 3300 comprises two tubes 3350, each tube 3350 being positioned in use on a different side of the patient’s head and extending across the respective cheek region, above the respective ear (superior to the otobasion superior on the patient’s head) to the elbow 3610 on top of the head of the patient 1000. This form of technology may be advantageous because, if a patient sleeps with their head on its side and one of the tubes 3350 is compressed to block or partially block the flow of gas along the tube 3350, the other tube 3350 remains open to supply pressurised gas to the patient. In other examples of the technology, the patient interface 3000 may comprise a different number of tubes, for example one tube, or two or more tubes.

[0333] In one example in which the patient interface has one tube 3350, the single tube 3350 is positioned on one side of the patient’s head in use (e.g. across one cheek region) and a strap forms part of the positioning and stabilising structure 3300 and is positioned on the other side of the patient’s head in use (e.g. across the other region) to assist in securing the patient interface 3000 on the patient’s head. For example, the tube 3350 and the strap may each be under tension in use in order to assist in maintaining the seal-forming structure 3100 in a sealing position.

[0334] In one form, the tube 3350 may be at least partially extensible so that the tube 3350 and the strap may adjust substantially equal lengths when worn by a patient. This may allow for substantially symmetrical adjustments between the tube 3350 and the strap so that the seal-forming structure remains substantially in the middle.

[0335] In the form of the technology shown in Fig. 3Z, the two tubes 3350 are fluidly connected at superior ends to each other and to the connection port 3600. In some examples, the two tubes 3350 are integrally formed while in other examples the tubes 3350 are formed separately but are connected in use and may be disconnected, for example for cleaning or storage. Where separate tubes are used, they may be indirectly connected together, for example each may be connected to a T-shaped connector. The T-shaped connector may have two arms/branches each fluidly connectable to a respective one of the tubes 3350. Additionally, the T-shaped connector may have a third arm or opening providing the connection port 3600 for fluid connection to the air circuit 4170 in use. The opening may be an inlet 3332 (see e.g., 7C) for receiving the flow of pressurized air.

[0336] In some forms, the third arm of the T-shaped connector may be substantially perpendicular to each of the first two arms.

[0337] In some forms, the third arm of the T-shaped connector may be obliquely formed with respect to each of the first two arms. [0338] In some forms, a Y-shaped connector may be used instead of the T-shaped connector. The first two arms may be oblique with respect to one another, and the third arm may be oblique with respect to the first two arms. The angled formation of the first two arms may be similar to the shape of the patient’s head in order to conform to the shape.

[0339] In some forms, at least one of the arms of the T-shaped connector (or Y-shaped connector) may be flexible. This may allow the connector to bend based on the shape of the patient’s head and/or a force in the positioning and stabilising structure 3300.

[0340] In some forms, at least one of the arms of the T-shaped connector (or Y-shaped connector) may be at least partially rigidised. This may assist in maintaining the shape of the connector so that bending of the connector does not close the airflow path.

[0341] The tubes 3350 may be formed from a flexible material, such as an elastomer, e.g. silicone or TPE, and/or from one or more textile and/or foam materials. The tubes 3350 may have a preformed shape and may be able to be bent or moved into another shape upon application of a force but may return to the original preformed shape in the absence of said force. The tubes 3350 may be generally arcuate or curved in a shape approximating the contours of a patient’s head between the top of the head and the nasal or oral region.

[0342] In some examples, the one or more tubes 3350 are crush resistant to resist being blocked if crushed during use, for example if squashed between a patient’s head and pillow, especially if there is only one tube 3350. The tubes 3350 may be formed with a sufficient structural stiffness to resist crushing or may be as described in US Patent No. 6,044,844, the contents of which are incorporated herein by reference.

[0343] Each tube 3350 may be configured to receive a flow of air from the connection port 3600 on top of the patient’s head and to deliver the flow of air to the seal-forming structure 3100 at the entrance of the patient’s airways. In the example shown in Fig. 3Z, each tube 3350 lies in use on a path extending from the plenum chamber 3200 across the patient’s cheek region and superior to the patient’s ear to the elbow 3610. For example, a portion of each tube 3350 proximate the plenum chamber 3200 may overlie a maxilla region of the patient’s head in use. Another portion of each tube 3350 may overlie a region of the patient’s head superior to an otobasion superior of the patient’s head. Each of the tubes 3350 may also lie over the patient’s sphenoid bone and/or temporal bone and either or both of the patient’s frontal bone and parietal bone. The elbow 3610 may be located in use over the patient’s parietal bone, over the frontal bone and/or over the junction therebetween (e.g. the coronal suture).

[0344] In certain forms of the present technology the patient interface 3000 is configured such that the connection port 3600 can be positioned in a range of positions across the top of the patient’s head so that the patient interface 3000 can be positioned as appropriate for the comfort or fit of an individual patient. In some examples, the headgear tubes 3350 are configured to allow movement of an upper portion of the patient interface 3000 (e.g. a connection port 3600) with respect to a lower portion of the patient interface 3000 (e.g. a plenum chamber 3200). That is, the connection port 3600 may be at least partially decoupled from the plenum chamber 3200. In this way, the seal-forming structure 3100 may form an effective seal with the patient’s face irrespective of the position of the connection port 3600 (at least within a predetermined range of positions) on the patient’s head.

[0345] As described above, in some examples of the present technology the patient interface 3000 comprises a seal-forming structure 3100 in the form of a cradle cushion which lies generally under the nose and seals to an inferior periphery of the nose (e.g. an under-the- nose cushion). The positioning and stabilising structure 3300, including the tubes 3350 may be structured and arranged to pull the seal-forming structure 3100 into the patient’s face under the nose with a sealing force in a posterior and superior direction (e.g. a posterosuperior direction). A sealing force with a posterosuperior direction may cause the seal-forming structure 3100 to form a good seal to both the inferior periphery of the patient’s nose and anterior-facing surfaces of the patient’s face, for example on either side of the patient’s nose and the patient’s lip superior.

[0346] Conduits forming part of the positioning and stabilising structure 3300, like headgear straps, may provide a force that contributes to the positioning and stabilising force FPSS- As illustrated in Fig. 3Z-1, the positioning and stabilising force FPSS may be the resultant force from the various forces of the different elements of the positioning and stabilising structure 3300. For example, each conduit may provide a force F_conduit directed in the posterior and respective lateral direction in order to hold the seal-forming structure 3100 against the patient’s face (into the upper lip and sealing under the nose) and oppose the effect of the positive pressure in the plenum chamber 3200 to lift off the face (i.e., F_pienum). The force F_Conduit directed may also be directed at least partially in the superior direction in order to overcome the gravitational force F_g.

[0347] In some forms, the conduits may provide a force directed into the patient’s head when the conduits are filled with pressurized air. The force may assist in gripping the patient’s head. The force may be caused by the inflation of the conduits during normal use. In some forms, the force may provide a cushioning effect to the patient’s head. The conduits may be designed in order to limit expansion in order to prevent over-gripping the patient’s head.

[0348] The position of the patient’s head may also change the gripping force of the conduits. For example, if the patient is sleeping on his side, the weight of the patient’s head may compress one conduit, and the other conduit (e.g., the lateral portion not between the patient’s head and a sleeping surface, like a pillow) may additionally expand in order to keep substantially the same flow rate of pressurized air. [0349] The gravitational force F_g may be opposed by a frictional force Ff, which may act in a direction directly opposite of the gravitational force F_g. As gravity pulls the seal-forming structure 3100 and the plenum chamber 3200 in the inferior direction (as viewed in Fig. 3A- 1), the frictional force Ff would act in the superior direction (e.g., against a patient’s face). For example, the patient may experience the frictional force Ff against his lip superior (and/or other surfaces of the patient’s face in contact with the seal-forming structure 3100) in order to oppose the motion in the inferior direction (which may help to stabilising the cushion in place). Although the frictional force Ff is shown specifically opposing the gravitational force F_g of the seal-forming structure 3100 and the plenum chamber 3200, components of an overall frictional force (not shown) would also oppose the gravitational force F_g associated with the positioning and stabilising structure 3300 and any other portions of the patient interface 3000. A force of friction can act along any place where the patient interface 3000 contacts the patient’s skin (or hair). The frictional force Ff extends in the opposite direction of the gravitational force F_g and along the patient’s skin (or hair).

[0350] In some forms, the sum of the various forces may equal zero so that the patient interface 3000 is at equilibrium (e.g., not moving along the patient’s face while in use). Specifically, the gravitational force F_g and the blowout force F_pienum tend to move the sealforming structure 3100 away from the desired sealing position. The positioning and stabilising force FPSS is applied in order to counteract the gravitational force F_g and the blowout force F_pienum (as well as any frictional forces Ff) and keep the seal-forming structure 3100 properly situated. Although the positioning and stabilising force FPSS may exceed the sum of the gravitational force F_g and the blowout force F_pienum (with any additional positioning and stabilising force FPSS being balanced by reaction force from the patient’s head acting on the portions of patient interface 3000) and still maintain the seal-forming structure 3100 in an appropriate sealing position, patient comfort may be sacrificed. Maximum patient comfort may be achieved when the net force on the patient interface 3000 is zero and the positioning and stabilising force FPSS is exactly strong enough to achieve this. In some examples the positioning and stabilising structure 3300 may be adjustable such that when fitted the positioning and stabilising force FPSS is greater than required to exactly balance the gravitational force F_g and the blowout force F_pienum to hold the patient interface 3000 against the patient’s head tightly enough that disruptive forces which may be experienced in use (such as tube drag or lateral shunting of the plenum chamber 3200 during side sleeping) do not disrupt the seal. As described below, various positions of the patient’s head while using the patient interface 3000 may determine the positioning and stabilising force FPSS necessary to achieve equilibrium. 5.3.4.1.2 Extendable and non-extendable tube portions

[0351] In some examples of the present technology, one or both of the tubes 3350 are not extendable in length. However, in some forms, the tubes 3350 may comprise one or more extendable tube sections, for example formed by an extendable concertina structure. In some forms, the patient interface 3000 may comprise a positioning and stabilising structure 3300 including at least one gas delivery tube comprising a tube wall having an extendable concertina structure. The patient interface 3000 shown in Fig. 3Z comprises tubes 3350, the superior portions of which comprise extendable tube sections each in the form of an extendable concertina structure 3362.

[0352] In some forms, the extendable concertina structure 3328 may be formed as a series of ridges and grooves on the surface of the tubes 3350. The concertina structure 3328 may be biased toward a retracted position, and may move to an expanded position when the patient dons the positioning and stabilising structure 3300. Because portions of the tubes 3350 may be substantially inextensible (e.g., non-extendable tube sections 3363), the concertina structures 3328 permit the positioning and stabilising structure 3300 to stretch in order to fit different sized heads. This may allow a single sized tube 3350 to be used with multiple sized heads. For example, the positioning and stabilising structure 3300 may be “one-size-fits-all” as a result of the concertina structure 3328. Alternatively, the tubes 3350 may be manufactured in multiple sizes (e.g., small, medium, large). The patient may select a length that most closely conforms to their head, and the concertina structures 3328 may make small adjustments in order to tailor the fit to the individual patient.

[0353] In some forms, the inlet 3332 may be disposed in the middle of the conduit 6320. For example, the tubes 3350 may be symmetric about the inlet 3332 through at least one axis. [0354] The cross-sectional shape of the non-extendable tube sections 3363 of the tubes 3350 may be circular, elliptical, oval, D-shaped or a rounded rectangle, for example as described in US Patent No. 6,044,844. A cross-sectional shape that presents a flattened surface of tube on the side that faces and contacts the patient’s face or other part of the head may be more comfortable to wear than, for example a tube with a circular cross-section.

[0355] In some examples of the present technology, the non-extendable tube sections 3363 connects to the plenum chamber 3200 from a low angle. The headgear tubes 3350 may extend inferiorly down the sides of the patient’s head and then curve anteriorly and medially to connect to the plenum chamber 3200 in front of the patient’s face. The tubes 3350, before connecting to the plenum chamber 3200, may extend to a location at the same vertical position as (or, in some examples, inferior to) the connection with the plenum chamber 3200. That is, the tubes 3350 may project in an at least partially superior direction before connecting with the plenum chamber 3200. A portion of the tubes 3350 may be located inferior to the plenum chamber 3200 and/or the seal forming structure 3100. The tubes 3350 may contact the patient’s face below the patient’s cheekbones, which may be more comfortable than contact on the patient’s cheekbones and may avoid excessively obscuring the patient’s peripheral vision.

5.3.4.1.3 Conduit headgear connection port

[0356] In certain forms of the present technology, the patient interface 3000 may comprise a connection port 3600 located proximal to a superior, lateral or posterior portion of a patient’s head. For example, in the form of the present technology illustrated in Fig 3Z, the connection port 3600 is located on top of the patient’s head (e.g. at a superior location with respect to the patient’s head). In this example the patient interface 3000 comprises an elbow 3610 forming the connection port 3600. The elbow 3610 may be configured to fluidly connect with a conduit of an air circuit 4170. The elbow 3610 may be configured to swivel with respect to the positioning and stabilising structure 3300 to at least partially decouple the conduit from the positioning and stabilising structure 3300. In some examples the elbow 3610 may be configured to swivel by rotation about a substantially vertical axis and, in some particular examples, by rotation about two or more axes. In some examples the elbow may comprise or be connected to the tubes 3350 by a ball-and-socket joint. The connection portion 3600 may be located in the sagittal plane of the patient’s head in use.

[0357] Patient interfaces having a connection port that is not positioned anterior to the patient’s face may be advantageous as some patients may find a conduit that connects to a patient interface anterior to their face to be unsightly and/or obtrusive. For example, a conduit connecting to a patient interface anterior to the patient’s face may be prone to interference with bedclothes or bed linen, particularly if the conduit extends inferiorly from the patient interface in use. Forms of the present technology comprising a patient interface having a connection port positioned superiorly to the patient’s head in use may make it easier or more comfortable for a patient to lie or sleep in one or more of the following positions: a side- sleeping position, a supine position (e.g. on their back, facing generally upwards) or in a prone position (e.g. on their front, facing generally downwards). Moreover, connecting a conduit to an anterior portion of a patient interface may exacerbate a problem known as tube drag in which the conduit exerts an undesired force upon the patient interface during movement of the patient’s head or the conduit, thereby causing dislodgement away from the face. Tube drag may be less of a problem when force is received at a superior location of the patient’s head than anterior to the patient’s face proximate to the seal-forming structure (where tube drag forces may be more likely to disrupt the seal).

5.3.4.1.4 Headgear Tube Fluid Connections

[0358] The two tubes 3350 are fluidly connected at their inferior ends to the plenum chamber 3200. In certain forms of the technology, the connection between the tubes 3350 and the plenum chamber 3200 is achieved by connection of two rigid connectors. The tubes 3350 and plenum chamber 3200 may be configured to enable the patient to easily connect the two components together in a reliable manner. The tubes 3350 and plenum chamber 3200 may be configured to provide tactile and/or audible feedback in the form of a ‘re-assuring click’ or a similar sound, so that the patient may easily know that each tube 3350 has been correctly connected to the plenum chamber 3200. In one form, the tubes 3350 are formed from a silicone or textile material and the inferior end of each of the silicone tubes 3350 is overmolded to a rigid connector made, for example, from polypropylene, polycarbonate, nylon or the like. The rigid connector on each tube 3350 may comprise a female mating feature configured to connect with a male mating feature on the plenum chamber 3200. Alternatively, the rigid connector on each tube 3350 may comprise a male mating feature configured to connect to a female mating feature on the plenum chamber 3200. In other examples the tubes 3350 may each comprise a male or female connector formed from a flexible material, such as silicone or TPE, for example the same material from which the tubes 3350 are formed.

[0359] In other examples a compression seal is used to connect each tube 3350 to the plenum chamber 3200. For example, a resiliently flexible (e.g. silicone) tube 3350 without a rigid connector may be configured to be squeezed to reduce its diameter so that it can be compressed into a port in the plenum chamber 3200 and the inherent resilience of the silicone pushes the tube 3350 outwards to seal the tube 3350 in the port in an air-tight manner. Alternatively, in a hard-to-hard type engagement between the tube 3350 and the plenum chamber 3200, each tube 3350 and/or plenum chamber 3200 may comprise a pressure activated seal, for example a peripheral sealing flange. When pressurised gas is supplied through the tubes 3350 the sealing flange may be urged against the join between the tubes and a circumferential surface around a port or connector of the plenum chamber 3200 to form or enhance a seal between the tube 3350 and plenum chamber 3200.

S.3.4.2 Headgear straps

[0360] In some forms, the positioning and stabilising structure 3300 may include headgear 3302 with at least one strap which may be worn by the patient in order to assist in properly orienting the seal -forming structure 3100 against the patient’s face (e.g., in order to limit or prevent leaks).

[0361] As described above, some forms of the headgear 3302 may be constructed from a textile material, which may be comfortable against the patient’s skin. The textile may be flexible in order to conform to a variety of facial contours. Although the textile may include rigidisers along a selected length, which may limit bending, flexing, and/or stretching of the headgear 3302.

[0362] In certain forms, the headgear 3302 may be at least partially extensible. For example, the headgear 3302 may include elastic, or a similar extensible material. For example, the entire headgear 3302 may be extensible or selected portions may be extensible (or more extensible than surrounding portions). This may allow the headgear 3302 to stretch while under tension, which may assist in providing a sealing force for the seal-forming structure 3100.

[0363] Two forms of the headgear, four-point headgear 3302-1 and two-point headgear 3302-2, are discussed in more detail below as illustrative examples.

5.3.4.2.1 Four-point connection

[0364] As shown in Fig. 7E, some forms of the headgear 3302-1 may be a four-point connection headgear. This means that the headgear 3302-1 may connect to four separate places on the plenum chamber 3200, on a frame connected to the plenum chamber 3200, and/or on arms connected to the plenum chamber 3200. The headgear 3302-1 may include four different straps providing a tensile force to help maintain the seal-forming structure 3100 in a sealing position. The positioning and stabilising structure 3300 of Fig. 3A may also be considered a four-point connection headgear.

[0365] In some forms, the headgear 3302-1 may include inferior straps 3304-1, which may connect to an inferior portion of the cushion 3050-1. The inferior straps 3304-1 may extend along the patient’s cheek toward a posterior region of the patient’s head. For example, the inferior straps 3304-1 may overlay the masseter muscle on either side of the patient’s face. The inferior straps 3304-1 may therefore contact the patient’s head below the patient’s ears. The inferior straps 3304-1 may meet at the posterior of the patient’s head, and may overlay the occipital bone and/or the trapezius muscle.

[0366] The headgear 3302-1 may also include superior straps 3305-1, which may overlay the temporal bones, parietal bone, and/or occipital bone. The superior straps 3305-1 may also connect to the tubes 3350 (e.g., by interfacing with the tabs 3320).

[0367] A rear strap 3307-1 may extend between the superior straps 3305-1 and between the inferior straps 3304-1. The inferior and superior straps 3304-1, 3305-1 on a given side (e.g., left or right) may also be connected to the rear strap 3307-1 adjacent to one another. The height of the rear strap 3307-1 may therefore be approximately the combined height of the inferior and superior strap 3304-1, 3305-1. The rear strap 3307-1 may overlay the occipital bone and/or the pariental bone in use. This may allow the rear strap 3307-1 to assist in anchoring the headgear 3302-1 to the patient’s head.

[0368] In the illustrated example, the headgear 3302-1 may be formed with a substantially X-shape. The inferior and superior straps 3304-1, 3305-1 may be connected to a rear strap 3307-1 using stitching, ultrasonic welding, or any similar process.

[0369] In some forms, the inferior straps 3304-1 are connected to a magnetic member 3306-1. For example, each inferior straps 3304-1 may be threaded through a magnetic member 3306-1, so that a length of each inferior strap 3304-1 may be adjusted. The magnetic members 3306-1 may removably connect to the magnets 3370-1 (described below), so that the inferior straps 3304-1 may be disconnected from the plenum chamber 3200, but the length of the inferior straps 3304-1 may not be affected.

[0370] In some forms, the superior straps 3305-1 may be connected directly to the tabs 3320 of the tubes 3350. The superior straps 3305-1 may be threaded through the tabs 3320 in order to adjust the length and control the tensile force of each superior strap 3305-1.

[0371] In some forms, the headgear 3302-1 may be used only with the nose and mouth cushion 3050-1 (e.g., because the nose-only cushion 3050-1 does not have four connection points). However, the headgear 3302-1 may be used interchangeably with the tubes 3350 and the rigidiser arms 3340.

S.3.4.2.2 Two-point connection

[0372] As shown in Fig. 7F, some forms of the headgear 3302-2 may be a two-point connection headgear. This means that the headgear 3302-2 may connect to two separate places.

[0373] In some forms, the headgear 3302-2 may be formed from a continuous piece of material. In other words, the headgear 3302-2 may not be formed from multiple straps connected (e.g., stitched) together. This may be comfortable for a patient as they will not be in contact with any seams or joints connecting different straps. In other forms, the headgear 3302-2 may be formed from multiple straps (e.g., two superior straps, a rear strap, etc.) that are connected together (e.g., with stitching, ultra-sonic welding, etc.).

[0374] In certain forms of the present technology, the positioning and stabilising structure 3300 comprises at least one headgear strap acting in addition to the tubes 3350 to position and stabilise the seal-forming structure 3100 at the entrance to the patient’s airways. As shown in Fig. 3Z, the patient interface 3000 comprises a strap 3307-2 forming part of the positioning and stabilising structure 3300. The strap 3307-2 may be known as a back strap or a rear headgear strap, for example. The rear strap 3307-2 may overlay the temporal bones, parietal bone, and/or occipital bone. In other examples of the present technology, one or more further straps may be provided. For example, patient interfaces 3000 according to examples of the present technology having a nose-and-mouth cushion may have a second, lower, strap configured to lie against the patient’s head proximate the patient’s neck and/or against posterior surfaces of the patient’s neck.

[0375] In the example shown in Fig. 3Z, strap 3310 of the positioning and stabilising structure 3300 is connected between the two tubes 3350 positioned on each side of the patient’s head and passing around the back of the patient’s head, for example overlying or lying inferior to the occipital bone of the patient’s head in use. The strap 3310 connects to each tube above the patient’s ears. With reference to Fig. 3Z, the positioning and stabilising structure 3300 comprises a pair of tabs 3320. In use a strap 3310 may be connected between the tabs 3320. The strap 3310 may be sufficiently flexible to pass around the back of the patient’s head and lie comfortably against the patient’s head, even when under tension in use. [0376] As shown in Fig. 7F, some forms of the headgear 3302-2 may be at least partially bifurcated. For example, a rear strap 3307-2 of the headgear 3302-2 (e.g., configured to contact the posterior portion of the patient’s head) may be wider than the surrounding portions of the headgear 3302-2. An intermediate section 3308-2 of the rear strap 3307-2 may include a slit 3309-2. A superior section of the rear strap 3307-2 may therefore be movable relative to the inferior section as a result of the slit 3309-2. This may allow the patient to have a larger strap coverage on the posterior region of their head, which may assist in better anchoring the headgear 3302-2 to the patient’s head since there is no inferior strap (e.g., 3304-1).

[0377] In some forms, the headgear 3302-2 may be used only with the nasal cushion 3050-2 (e.g., because the nose and mouth cushion 3050-1 does not have four connection points). However, the headgear 3302-2 may be used interchangeably with the tubes 3350 and the rigidiser arms 3340.

S.3.4.3 Rigidiser Arm

[0378] As shown in Fig. 7D, a rigidiser arm 3340 may be an elongated, rigid member that assists in maintaining the cushion (e.g., the nose and mouth cushion 3050-1 or the nasal cushion 3050-2) in an operating position. The rigidiser arm 3340 may contact a side of the patient’s head and provide a force to limit slipping of the seal-forming structure 3100 from the patient’s nose and/or mouth.

[0379] In some forms, the rigidiser arm 3340 is constructed from a rigid material (e.g., plastic). The rigid material may not permit the rigidiser arm 3340 to stretch. Additionally, the rigidiser arm 3340 may be substantially inflexible and may be unable to bend. The rigidiser arm 3340 may be pre -molded into a desired shape in order to fit a patient’s head. For example, the rigidiser arms 3340 may be molded with a curved shape to substantially correspond to the shape of the side of the patient’s head (e.g., overlaying the masseter muscle and/or the temporal bone).

[0380] In certain forms, the rigidiser arm 3340 may be molded in order to conform to a specific patient’s head (e.g., the rigidiser arm 3340 is customized).

[0381] In some forms, the rigidiser arm 3340 may be flexible along at least one direction. For example, the rigidiser arm 3340 may be flexible about its width and may be inflexible along its length. In other words, the rigidiser arm 3340 may be bendable about an axis along the width of the rigidiser arm 3340, but may be unable to bend about an axis perpendicular to the rigidiser arm 3340. This may allow an individual patient to adjust the rigidiser arm 3340 in order to better fit their individual head. [0382] In certain forms, the rigidiser arm 3340 may remain in the new position after being bent. This may allow a patient adjust the shape of the rigidiser arm 3340 for their specific head and then the rigidiser arm 3340 will keep the desired shape while in use in order to promote patient comfort.

[0383] In some forms, a first end 3342 of the rigidiser arm 3340 may be a free end and a second end 3344 (e.g., opposite of the first end 3342) of the rigidiser arm 3340 may be fixed. The first end 3342 may be curved in order to minimize sharp edges that could cause patient discomfort. The first end 3342 may also overlay the patient’s head proximate to the temporal bone, in use. The second end 3344 may be fixed to an arm connection structure 3504.

[0384] In some forms, the arm connection structure 3504 may be similar to the conduit connection structure 3500. For example, the arm connection structure 3504 and the conduit connection structure 3500 may have substantially the same shape. This may allow either the conduit connection structure 3500 or the arm connection structure 3504 to fit into the groove (e.g., 3266-1 or 3266-2) and connect to the plenum chamber inlet port 3254. The arm connection structure 3504 may connect to the nose and mouth cushion 3050-1 or the nose- only cushion 3050-2 in substantially the same way as the conduit connection structure 3500 (e.g., via a snap fit, press fit, friction fit, etc.).

[0385] In some forms, the arm connection structure 3504 may act as a plug for the plenum chamber inlet port 3254 (e.g., either 3254-1 and/or 3254-2). Unlike the tubes 3350, the rigidiser arm 3340 does not convey pressurized air to the plenum chamber 3200. The rigidised arm 3340 may be used with a “tube down” configuration, where a hose is connected to the vent opening 3402 (e.g., either 3402-1 and/or 3402-2), and conveys air into the plenum chamber 3200 through the vent opening 3402. In this example, air does not need to travel into or out of the plenum chamber inlet openings 3254. Thus, the arm connection structure 3504 may form a seal with the plenum chamber inlet opening 3254 in order to limit airflow into or out of the plenum chamber 3200.

5.3.5 Vent

[0386] 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.

[0387] In certain forms the vent 3400 is configured to allow a continuous vent flow from an interior of the plenum chamber 3200 to ambient whilst the pressure within the plenum chamber is positive with respect to ambient. The vent 3400 is configured such that the vent flow rate has a magnitude sufficient to reduce rebreathing of exhaled CO2 by the patient while maintaining the therapeutic pressure in the plenum chamber in use.

[0388] One form of vent 3400 in accordance 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. [0389] The vent 3400 may be located in the plenum chamber 3200. Alternatively, the vent 3400 is located in a decoupling structure, e.g., a swivel.

[0390] As shown in Fig. 7N, a vent 3450 may be used with the patient interface 3000. The vent 3450 may have a substantially similar shape to the vent opening 3402-1 (e.g., a substantially circular shape).

[0391] The vent 3450 may be used with either the mouth and nose plenum chamber 3200-1 (e.g., illustrated in Figs. 7A) or the nose-only plenum chamber 3200-2 (e.g., illustrated in Figs. 7B).

[0392] With continued reference to Fig. 7A, the vent 3450 may include a vent housing 3404, which may be configured to engage with the vent opening 3402. The vent housing 3404 may be constructed from a rigid material or a semi-rigid material. For example, the vent housing 3404 may be constructed from plastic, metal, or any similar material. The vent housing 3404 may add rigidity to the patient interface 3000 (e.g., to limit unwanted bending that may affect the position of the seal-forming structure 3100 on the patient’s face).

[0393] The vent housing 3404 may include an anterior surface 3408, a posterior surface 3412, and a groove 3416. The anterior surface 3408 faces away from the patient’s face in use, and may be positioned outside the pressurized volume of the plenum chamber 3200. The posterior surface 3412 is disposed opposite to the anterior surface 3408. In use, the posterior surface 3412 may face the patient and may be disposed within the pressurized volume of the plenum chamber 3200. The groove 3416 may be formed between the anterior and posterior surfaces 3408, 3412. A portion of the plenum chamber 3200 may be received within the groove 3416 in order to retain the vent 3400 in position.

[0394] In some forms, a diffuser 3448 may be used with the vent housing 3404. The diffuser 3448 may assist with limiting the decibel output from any of the patient interface 3000 (or any other patient interface). Specifically, the diffuser 3448 may assist in limiting the decibel level associated with air output from the patient interface 3000 (e.g., exhaled air), although the diffuser 3448 may limit the decibel level of at any point in the patient interface. [0395] In certain forms, the diffuser 3448 may diffuse, and therefore slow, the exhaust gas exiting the plenum chamber 3200 and passing through the vent housing 3404. The diffuser 3448 may assist in avoiding jetting and associated discomfort to the patient and/or bed partner (e.g., noise caused by jetting against a pillow, sheets, bedclothes, etc.).

[0396] In some forms, the diffuser may include an anterior surface 3456 that faces away from the patient in use. An outer diameter of the anterior surface 3456 may be less than an inner diameter of the vent housing 3404 proximate to the anterior surface 3408. This may form a gap 3464 through which air may travel. 5.3.6 Decoupling structure(s)

[0397] In one form the patient interface 3000 includes at least one decoupling structure, for example, a swivel or a ball and socket.

5.3.7 Connection port

[0398] Connection port 3600 allows for connection to the air circuit 4170.

5.3.8 Forehead support

[0399] In one form, the patient interface 3000 includes a forehead support 3700.

5.3.9 Anti-asphyxia valve

[0400] In one form, the patient interface 3000 includes an anti-asphyxia valve.

5.3.10 Ports

[0401] In one form of the present technology, a patient interface 3000 includes one or more ports that allow access to the volume within the plenum chamber 3200. In one form this allows a clinician to supply supplementary oxygen. In one form, this allows for the direct measurement of a property of gases within the plenum chamber 3200, such as the pressure.

5.3.11 Modularity

[0402] As described above, the cushion, headgear, and sleeves may come in different styles, which may correspond to different uses (e.g., mouth breathing, nasal breathing, etc.). A patient or clinician may select certain combinations of cushions, headgear, and sleeves in order to optimize the effectiveness of the therapy and/or the individual patient’s comfort. An example of this sort of modular design is described in PCT/SG2022/050777 filed 28 October 2022, incorporated herein by reference in its entirety.

[0403] In some forms, the different styles of cushions, headgear, and sleeves may be used interchangeably with one another in order to form different combinations of patient interfaces. This may be beneficial from a manufacturing prospective because wider variety of patient interfaces may be created using fewer parts. Additionally or alternatively, the various combinations may allow a patient to change styles of patient interface without changing the every component.

[0404] Air may be delivered to the patient in one of two main ways. In one example, the patient may receive the flow of pressurized air through headgear tubes 3350 (see e.g., Fig.

3Z). This may be referred to as a “tube up” configuration and may position a connection port at the top of the patient’s head. In other example, the patient may receive the flow of pressurized air through a conduit connected to the plenum chamber 3200, for example through the connection port 3600 (see e.g., Fig. 3A). This may be referred to a “tube down” configuration where the airflow conduit is positioned in front of the patient’s face. Different patients may be more comfortable with one style of air delivery over the other (e.g., because of the patient’s sleep style). Therefore, it may be beneficial to allow a single style of patient interface to be used in either the “tube up” or “tube down” configuration. [0405] The patient interface may be part of a modular assembly with a variety of interchangeable components that may be swapped out by a patient and/or clinician for one or more components for a different style. The following description describes the various combinations that may be created by assembling the different components together.

5.3.11.1 Sleeve

[0406] In some forms, to allow for modularity, a sleeve may be used with the tubes 3350 and/or the rigidisier arms 3340. The sleeve may at least partially surround the tubes 3350 and/or the rigidiser arms 3340. As shown in Figs. 7G to 71, different shapes of sleeves may be used, which may correspond to different types of positioning and stabilising structures 3300. In some forms, the configuration of the sleeve may be customized to fit a particular user’s face. For instance, the sleeves may be configured in a relatively more posterior region of the patient’s head.

[0407] In some forms, the sleeve may be constructed from a comfortable material. For example, the sleeve may be constructed from a textile material, a foam material, or a combination of the two. The comfortable material may contact the patient in use, and may feel soft against the patient’s skin in order to improve patient compliance.

[0408] The material may also be flexible in order to assist in donning or doffing the sleeve from the tube 3350 or the rigidiser arms 3340. For example, the material may allow the sleeve to bend in order to conform to the shape of the tubes or conduit headgear 3350 or the rigidiser arms 3340, which may change depending on the shape of an individual patient’s head.

[0409] In some forms, the sleeve may also be at least partially elastic (e.g., the material may allow the sleeve to stretch). The elastic material may help the sleeve stretch in order to fit around the tubes 3350 or the rigidiser arms 3340. The elastic material may then return to an initial position that is snug against the tubes 3350 or the rigidiser arms 3340 in order to limit the sleeve from sliding while in use.

[0410] As described in more detail below, some forms of the sleeves may be specific to a rigidising element (e.g., tubes 3350 and/or rigidiser arms 3340). However, the sleeves may assist the rigidising elements in connecting interchangeably with the version or styles of cushions (e.g., the mouth and nose cushion 3050-1, the nose-only cushion 3050-2, etc.).

5.3.11.1.1 Conduit Sleeve

[0411] As shown in Fig. 7G, one example of a sleeve is a conduit sleeve 3351, which may be usable with the tubes 3350 described above.

[0412] As shown in Fig. 7G, the conduit sleeve 3351 may include a curved shape that may be similar to the shape of the tubes 3350 shown in Fig. 7C. The flexible material used to construct the conduit sleeve 3351 may allow the conduit sleeve 3351 to further curve in order to correspond to the shape of the tubes 3350 (e.g., when worn by the patient). [0413] In some forms, the conduit sleeve 3351 may include a first or superior opening 3352. The superior opening 3352 may be disposed at one end of the conduit sleeve 3351. The superior opening 3352 may be an opening to a passage that extends along at least a portion of the conduit sleeve 3351.

[0414] As shown in Fig. 7G, some forms of the conduit sleeve 3351 may also include an inferior extension 3354. The inferior extension 3354 may be positioned on an opposite end of the conduit sleeve 3351 from the superior opening 3352. The conduit sleeve 3351 may be customized to fit a particular user’s face. For instance, the inferior extension 3354 of the conduit sleeve 3351 may be configured in a relatively more posterior region or anterior region of the patient’s head.

[0415] Some forms of the inferior extension 3354 may include a rigid or semi-rigid piece (e.g., within the sleeve 3351). The rigid or semi-rigid piece may be constructed from a plastic material, or a similar material. Alternatively, the inferior extension 3354 may be stiffened using a manufacturing process (e.g., stitching rigidised thread, flat knitting, using thicker material).

[0416] As shown in Fig. 7G, some forms of the inferior extension 3354 may include a connection member 3356. In the illustrated example, the connection member 3356 may be a magnet, although in other examples, the connection member 3356 may be a different type of connector (e.g., a mechanical fastener, an adhesive, hook and loop material, etc.). The connection member 3356 may also be positioned at an end of the inferior extension 3354, although the connection member 3356 could alternatively be positioned anywhere along the inferior extension 3354.

[0417] In some forms, the connection member 3356 (e.g., a magnet) may be removably connected to the magnets 3370-1 of the headgear 3302-1. For example, when the conduit sleeves 3351 are connected to the tubes 3350 (see e.g., Fig. 7J), the magnets 3370-1 connected to the inferior straps 3304-1 may be removably connected to the connection member 3356 in order to provide the tensile force.

5.3.11.1.2 Four-point arm sleeve

[0418] As shown in Fig. 7H, another example of a sleeve is a four-point arm sleeve 3380, which may be usable with the rigidiser arms 3340 described above.

[0419] As shown in Fig. 7H, the four-point arm sleeve 3380 may include a curved shape that may be similar to the shape of the rigidiser arm 3340 shown in Fig. 7D. The flexible material used to construct the four-point arm sleeve 3380 may allow the four-point arm sleeve 3380 to further curve in order to correspond to the shape of the rigidiser arm 3340 (e.g., when worn by the patient and/or went bent by the patient). [0420] As shown in Fig. 7H, some forms of the four-point arm sleeve 3380 may include an inferior extension 3384. The inferior extension 3384 may be positioned at an end of the four-point arm sleeve 3380.

[0421] In the illustrated example, the shape and/or structure of the inferior extension 3384 is substantially the same as the shape of the inferior extension 3354. For example, the inferior extension 3384 may be more rigid as compared to the rest of the four -point arm sleeve 3380 (e.g., as a result of rigidising thread or rigid material).

[0422] As shown in Fig. 7H, some forms of the inferior extension 3384 may include a connection member 3386. In the illustrated example, the connection member 3386 may be a magnet, although in other examples, the connection member 3386 may be a different type of connector (e.g., a mechanical fastener, an adhesive, hook and loop material, etc.). The connection member 3386 may also be positioned at an end of the inferior extension 3384, although the connection member 3386 could alternatively be positioned anywhere along the inferior extension 3384.

[0423] In some forms, the connection member 3386 (e.g., a magnet) may be removably connected to the magnets 3370-1 of the headgear 3302-1. For example, when the four-point arm sleeves 3380 are connected to the rigidiser arm 3340 (see e.g., Fig. 7K), the magnets 3370-1 connected to the inferior straps 3304-1 may be removably connected to the connection member 3386 in order to provide the tensile force.

[0424] As shown in Fig. 7H, the four-point arm sleeve 3380 may include a pair of tabs 3394, which may be similar to the tab 3320 on the tubes 3350. When the four-point arm sleeve 3380 is worn by the patient, the tabs 3394 may be positioned in substantially the same place on the patient’s head as where the tabs 3320 are positioned when the patient wears the tubes 3350.

5.3.11.1.3 Two-point arm sleeve

[0425] As shown in Fig. 71, yet another example of a sleeve is a two-point arm sleeve 3380-1, which may be usable with the rigidiser arms 3340 described above.

[0426] In some forms, the two-point arm sleeve 3380-1 may be similar to the four-point arm sleeve 3380 described above. Only some similarities and differences may be described below.

[0427] As shown in Fig. 71, the two-point arm sleeve 3380-1 may include an inferior opening 3388-1 that is positioned at an end of the two-point arm sleeve 3380-1. The inferior opening 3388-1 may form an opening to a passageway through the two-point arm sleeve 3380-1. In the illustrated example, the inferior opening 3388-1 may open into a surface of the conduit sleeve 3380-1.

[0428] As shown in Fig. 71, the two-point arm sleeve 3380-1 may include a pair of tabs 3394-1, which may be similar to the tab 3320 on the tubes 3350. When the two-point arm sleeve 3380-1 is worn by the patient, the tabs 3394-1 may be positioned in substantially the same place on the patient’s head as where the tabs 3320 are positioned when the patient wears the tubes 3350.

5.3.11.2 Assembled Patient Interfaces

[0429] As illustrated in Figs. 7J to 7M, the various elements described above may be combined into four different patient interfaces. The different patient interfaces may allow patients to use different styles based on their individual comfort. The modularity of the different elements (e.g., the ability to be used in multiple styles of patient interfaces) may simplify manufacturing and/or may allow a patient to more easily switch between styles of patient interfaces.

5.3.11.2.1 Nose and Mouth Mask Tube Up Configuration

[0430] As illustrated in Fig. 7J, the patient may wear the cushion 3050-1 in a tube-up configuration with the tubes 3350 and the four-point headgear 3302-1. This assembly may form a tube up nose and mouth patient interface 3000-1.

[0431] In some forms, a conduit sleeve may be used with the tubes 3350 in order to enable a patient to experience the “tube up” air delivery style with the mouth and nose cushion 3050-1. As is described below, the conduit sleeve provides additional connection locations for connecting the four-point headgear 3302-1. However, other forms of connectors aside from or in addition to the conduit sleeve may be used.

[0432] In the illustrated example, the conduit sleeves may be connected to the tubes 3350 of the positioning and stabilising structure 3300. The tubes 3350 (via the conduit connection structure 3500), may be used to connect the tubes 3350 to the cushion 3050-1. The conduit sleeves provide the magnets in order to connect to the magnets 3370-1 (see e.g., Fig. 7E) of the four-point headgear 3302-1. Alternatively, a different connection form may be used.

[0433] As illustrated in Fig. 7J, the four-point headgear 3302-1 may connect in four separate locations in order to provide a tensile force that maintains the cushion 3050-1 in a sealing position on the patient’s head.

[0434] For example, the inferior straps 3304-1 (e.g., via the magnetic members 3306-1) may removably connect to the magnets of the conduit sleeves. In use, each inferior strap 3304-1 may contact the patient’s cheek (e.g., overlaying the masseter muscle). The inferior straps 3304-1 may also extend below the patient’s ears.

5.3.11.2.2 Nose and Mouth Mask Tube Down Configuration

[0435] As illustrated in Fig. 7K, the patient may wear the cushion 3050-1 in a tubedown configuration with the rigidiser arms 3340 and the four-point headgear 3302-1. This assembly may form a tube down nose and mouth patient interface 3000-2. [0436] In some forms, a conduit sleeve may be used with the rigidiser arms 3340 in order to enable a patient to experience the “tube down” air delivery style with the mouth and nose cushion 3050-1. As is described below, the conduit sleeve provides additional connection locations for connecting the four-point headgear 3302-1. However, other forms of connectors aside from or in addition to the conduit sleeve may be used.

[0437] In the illustrated example, the conduit sleeves may be connected to the rigidiser arms 3340 of the positioning and stabilising structure 3300. The rigidiser arms 3340 (via the conduit connection structure 3504), may be used to connect the rigidiser arms 3340 to the cushion 3050-1. The conduit sleeves provide the magnets in order to connect to the magnets 3370-1 (see e.g., Fig. 7E) of the four-point headgear 3302-1. Alternatively, a different connection form may be used.

[0438] As illustrated in Fig. 7K, the four-point headgear 3302-1 may connect in four separate locations in order to provide a tensile force that maintains the cushion 3050-1 in a sealing position on the patient’s head.

[0439] For example, the inferior straps 3304-1 (e.g., via the magnetic members 3306-1) may removably connect to the magnets of the conduit sleeves. In use, each inferior strap 3304-1 may contact the patient’s cheek (e.g., overlaying the masseter muscle). The inferior straps 3304-1 may also extend below the patient’s ears.

5.3.11.2.3 Nose Mask Tube Up Configuration

[0440] As illustrated in Fig. 7L, the patient may wear the cushion 3050-2 in a tube-up configuration with the tubes 3350 and the two-point headgear 3302-2. This assembly may form a tube up nose only patient interface 3000-3

[0441] A conduit sleeve may be used with the tubes 3350, and may provide additional comfort to the patient. The sleeve may not add additional connection points to connect the positioning and stabilising structure 3300 on the cushion 3050-2. In the illustrated example, the tubes 3350 of the positioning and stabilising structure 3300 may be connected directly to the cushion 3050-2.

[0442] As illustrated in Fig. 7L, the two-point headgear 3302-2 may connect to the tabs 3320 on the tubes 3350 in order to provide a tensile force that maintains the cushion 3050-2 in a sealing position on the patient’s head.

5.3.11.2.4 Nose Mask Tube Down Configuration

[0443] As illustrated in Fig. 7M, the patient may wear the cushion 3050-2 in a tube -up configuration with the rigidiser arms 3340 and the two-point headgear 3302-2. This assembly may form a tube down nose only patient interface 3000-4.

[0444] A conduit sleeve may be used with the rigidiser arms 3340, and may provide additional comfort to the patient. The sleeve may not add additional connection points to connect the positioning and stabilising structure 3300 on the cushion 3050-2. In the illustrated example, the rigidiser arms 3340 of the positioning and stabilising structure 3300 may be connected directly to the cushion 3050-2.

[0445] As illustrated in Fig. 7M, the two-point headgear 3302-2 may connect to the tabs 3320 on the sleeve in order to provide a tensile force that maintains the cushion 3050-2 in a sealing position on the patient’s head.

5.3.11.2.5 Modularity of Elements

[0446] Fig. 7P illustrates how the different elements can be combined in order to form the four different patient interfaces described above. As illustrated, the different components may be reused for different styles of patient interfaces. This may allow for easier manufacturing and assembly, because a large number of the same components may be produced and used in a variety of styles. The only components not used in multiple styles may be the sleeves. However, the sleeves may be easier to manufacture. Fig. 70 shows a portion of air circuit 4170 that may interface with the patient interface, while Fig. 7N shows a vent 3404 that may interchangeably replace the air circuit shown in Fig. 70, depending on the style of the patient interface.

5.4 RPT DEVICE

[0447] An RPT device 4000 in accordance with one aspect of the present technology comprises mechanical, pneumatic, and/or electrical components and is configured to execute one or more algorithms 4300, such as any of the methods, in whole or in part, described herein. The RPT device 4000 may be configured to generate a flow of air for delivery to a patient’s airways, such as to treat one or more of the respiratory conditions described elsewhere in the present document.

[0448] In one form, the RPT device 4000 is constructed and arranged to be capable of delivering a flow of air in a range of -20 L/min to +150 L/min while maintaining a positive pressure of at least 4 cmH20, or at least 10cmH2O, or at least 20 cmH20.

[0449] The RPT device may have an external 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.

[0450] The pneumatic path of the RPT device 4000 may comprise one or more air path items, e.g., an inlet air filter 4112, an inlet muffler 4122, a pressure generator 4140 capable of supplying air at positive pressure (e.g., a blower 4142), an outlet muffler 4124 and one or more transducers 4270, such as pressure sensors 4272 and flow rate sensors 4274.

[0451] One or more of the air path items may be located within a removable unitary structure which will be referred to as a pneumatic 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.

[0452] The RPT device 4000 may have an electrical power supply 4210, one or more input devices 4220, a pressure generator 4140, and one or more transducers 4270. Electrical components 4200 may be mounted on a single Printed Circuit Board Assembly (PCBA) 4202. In an alternative form, the RPT device 4000 may include more than one PCBA 4202.

5.4.1 RPT device mechanical & pneumatic components

[0453] 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.

5.4.1.1 Air filter(s)

[0454] 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.

[0455] In one form illustrated in Fig. 4B, an inlet air filter 4112 is located at the beginning of the pneumatic path upstream of a pressure generator 4140.

[0456] In one form illustrated in Fig. 4B, 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 or 3800.

5.4.1.2 Muffler(s)

[0457] An RPT device in accordance with one form of the present technology may include a muffler 4120, or a plurality of mufflers 4120.

[0458] In one form of the present technology (see e.g., Fig. 4B), an inlet muffler 4122 is located in the pneumatic path upstream of a pressure generator 4140.

[0459] 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 or 3800.

5.4.1.3 Pressure generator

[0460] In one form of the present technology, a pressure generator 4140 for producing a flow, or a supply, of air at positive pressure is a controllable blower 4142. For example, the blower 4142 may include a brushless DC motor 4144 with one or more impellers. The impellers may be located in a volute. The blower may be capable of delivering a supply of air, for example at a rate of up to about 120 litres/minute, at a positive pressure in a range from about 4 cmH20 to about 20 cmH20, or in other forms up to about 30 cmH20 when delivering respiratory pressure therapy. 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. WO 2013/020167. [0461] 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.

5.4.1.4 Transducer(s)

[0462] Transducers may be internal 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 interface. External transducers may be in the form of non-contact sensors such as a Doppler radar movement sensor that transmit or transfer data to the RPT device.

[0463] In one form of the present technology (see e.g., Fig. 4B), one or more transducers 4270 are located upstream and/or downstream of the pressure generator 4140. The one or more transducers 4270 may be constructed and arranged to generate signals representing properties of the flow of air such as a flow rate, a pressure or a temperature at that point in the pneumatic path.

[0464] In one form of the present technology, one or more transducers 4270 may be located proximate to the patient interface 3000 or 3800.

[0465] In one form, a signal from a transducer 4270 may be filtered, such as by low- pass, high-pass or band-pass filtering.

5.4.1.5 Anti-spill back valve

[0466] As shown in Fig. 4B, one form of the present technology, an anti-spill back valve 4160 is located between the humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is constructed and arranged to reduce the risk that water will flow upstream from the humidifier 5000, for example to the motor 4144.

5.4.2 RPT device electrical components

5.4.2.1 Power supply

[0467] A power supply 4210 may be located internal or external of the external housing 4010 of the RPT device 4000.

[0468] 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.

5.4.2 Input devices

[0469] 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 buttons, switches or dials may, in one form, be physically connected to the external housing 4010, or may, in another form, be in wireless communication with a receiver that is in electrical connection to a central controller. [0470] 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.

5.5 AIR CIRCUIT

[0471] An air circuit 4170 in accordance with an aspect of the present technology is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components such as RPT device 4000 and the patient interface 3000 or 3800.

[0472] In particular, the air circuit 4170 may be in fluid connection with the outlet of the pneumatic block 4020 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 inhalation and exhalation. In other cases a single limb is used.

[0473] In some forms, the air circuit 4170 may comprise one or more heating elements configured to heat air in the air circuit, for example to maintain or raise the temperature of the air. The heating element may be in a form of a heated wire circuit, and may comprise one or more transducers, 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 8,733,349, which is incorporated herewithin in its entirety by reference.

5.5.1 Supplementary gas delivery

[0474] In one form of the present technology, supplementary gas, e.g. 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 patient interface 3000 or 3800.

5.6 HUMIDIFIER

5.6.1 Humidifier overview

[0475] In one form of the present technology there is provided a humidifier 5000 (e.g. as shown in Fig. 5A) to change the absolute humidity of air or gas for delivery to a patient relative to ambient 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.

[0476] 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 humidifier 5000 may further comprise a humidifier base 5006, which may be adapted to receive the humidifier reservoir 5110 and comprise a heating element 5240. 5.6.2 Humidifier components

5.6.2.1 Water reservoir

[0477] 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 evaporated 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 humidification 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 millilitres (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.

[0478] According to one aspect, the water reservoir 5110 is configured to add humidity to a flow of air from the RPT device 4000 as the flow of air travels therethrough. In one form, the water reservoir 5110 may be configured to encourage the flow of air to travel in a tortuous path through the reservoir 5110 while in contact with the volume of water therein.

[0479] According to one form, the reservoir 5110 may be removable from the humidifier 5000, for example in a lateral direction as shown in Fig. 5 A and Fig. 5B. [0480] The reservoir 5110 may also be configured to discourage egress of liquid therefrom, such as when the reservoir 5110 is displaced and/or rotated from its normal, working orientation, such as through any apertures and/or in between its sub -components. 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.

5.6.2.2 Conductive portion

[0481] According to one arrangement, the reservoir 5110 comprises a conductive portion 5120 configured to allow efficient transfer of heat from the heating element 5240 to the volume of liquid in the reservoir 5110. In one form, the conductive portion 5120 may be arranged 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.

5.6.2.3 Humidifier reservoir dock

[0482] 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.

5.6.2.4 Water level indicator

[0483] 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 provide 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 provided by the water level indicator 5150 may include an indication 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.

5.6.2.5 Heating element

[0484] 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. WO 2012/171072, which is incorporated herewith by reference in its entirety.

[0485] In some forms, the heating element 5240 may be provided in the humidifier base 5006 where heat may be provided to the humidifier reservoir 5110 primarily by conduction as shown in Fig. 5B.

5.7 BREATHING WAVEFORMS

[0486] Fig. 6 shows a model typical breath waveform of a person while sleeping. The horizontal axis is time, and the vertical axis is respiratory flow rate. While the parameter values may vary, a typical breath may have the following approximate values: tidal volume Vt 0.5L, inhalation time Ti 1.6s, peak inspiratory flow rate Qpeak 0.4 L/s, exhalation time Te 2.4s, peak expiratory flow rate Qpeak -0.5 L/s. The total duration of the breath, Ttot, is about 4s. The person typically breathes at a rate of about 15 breaths per minute (BPM), with Ventilation Vent about 7.5 L/min. A typical duty cycle, the ratio of Ti to Ttot, is about 40%.

5.8 RESPIRATORY THERAPY MODES

[0487] Various respiratory therapy modes may be implemented by the disclosed respiratory therapy system.

5.9 GLOSSARY

[0488] For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the following definitions may apply. In other forms of the present technology, alternative definitions may apply. 5.9.1 General

[0489] 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 combination of breathable gases, e.g. oxygen enriched air.

[0490] Ambient'. In certain forms of the present technology, 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.

[0491] For example, ambient 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 humidity outside the room where a patient is sleeping.

[0492] In another example, ambient pressure may be the pressure immediately surrounding or external to the body.

[0493] 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 sources outside the room.

[0494] 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 presence or absence of indications of SDB events.

[0495] Continuous Positive Airway Pressure ( CPAP) therapy. Respiratory pressure therapy in which the treatment pressure is approximately constant through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for example, 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.

[0496] Flow rate'. The volume (or mass) of air delivered per unit time. Flow rate may refer to an instantaneous quantity. 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 reference to flow rate will be a reference to a vector quantity, namely a quantity having both magnitude and direction. Flow rate may be given the symbol Q. ‘Flow rate’ is sometimes shortened to simply ‘flow’ or ‘airflow’.

[0497] In the example of patient respiration, a flow rate may be nominally positive for the inspiratory portion of a breathing cycle of a patient, and hence negative for the expiratory portion of the breathing cycle of a patient. Device flow rate, Qd, is the flow rate of air leaving the RPT device. Total flow rate, Qt, is the flow rate of air and any supplementary gas reaching the patient interface via the air circuit. Vent flow rate, Qv, is the flow rate of air leaving a vent to allow washout of exhaled gases. Leak flow rate, QI, is the flow rate of leak from a patient interface system or elsewhere. Respiratory flow rate, Qr, is the flow rate of air that is received into the patient's respiratory system.

[0498] Flow therapy. Respiratory therapy comprising the delivery of a flow of air to an entrance to the airways at a controlled flow rate referred to as the treatment flow rate that is typically positive throughout the patient’s breathing cycle.

[0499] Humidifier. The word humidifier will be taken to mean a humidifying apparatus constructed and arranged, or configured with a physical structure to be capable of providing a therapeutically beneficial amount of water (H2O) vapour to a flow of air to ameliorate a medical respiratory condition of a patient.

[0500] 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.

[0501] 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 pressure levels at the end of an air circuit.

[0502] 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 quantified by measuring sound power/pressure levels of the object in question according to ISO 3744.

[0503] 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 of the patient interface. [0504] Oxygen enriched air: Air with a concentration of oxygen greater than that of atmospheric air (21%), for example at least about 50% oxygen, at least about 60% oxygen, at least about 70% oxygen, at least about 80% oxygen, at least about 90% oxygen, at least about 95% oxygen, at least about 98% oxygen, or at least about 99% oxygen. “Oxygen enriched air” is sometimes shortened to “oxygen”.

[0505] Medical Oxygen: Medical oxygen is defined as oxygen enriched air with an oxygen concentration of 80% or greater.

[0506] Patient: A person, whether or not they are suffering from a respiratory condition.

[0507] Pressure: Force per unit area. Pressure may be expressed in a range of units, including cmlLO. g-f/cm² and hectopascal. 1 cmlLO is equal to 1 g-f/cm² and is approximately 0.98 hectopascal (1 hectopascal = 100 Pa = 100 N/m² = 1 millibar ~ 0.001 atm). In this specification, unless otherwise stated, pressure is given in units of cmlLO. [0508] 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 interface pressure Pm at the current instant of time, is given the symbol Pt.

[0509] Respiratory Pressure Therapy. 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. [0510] Ventilator. A mechanical device that provides pressure support to a patient to perform some or all of the work of breathing.

5.9.1.1 Materials & their properties

[0511] Hardness: Refers to durometer or indentation hardness, which is a material property measured by indentation of an indentor (e.g., as measured in accordance with ASTM D2240).

• ‘Soft’ materials may include silicone or thermo-plastic elastomer (TPE), and may, e.g. readily deform under finger pressure.

• ‘Hard’ materials may include polycarbonate, polypropylene, and may not e.g. readily deform under finger pressure.

[0512] Silicone or Silicone Elastomer: A synthetic rubber. In this specification, a reference to silicone is a reference to liquid silicone 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 exemplary 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.

[0513] Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.

5.9.1.2 Mechanics

[0514] Axes: a. Neutral axis: An axis in the cross-section of a beam or plate along which there are no longitudinal stresses or strains. b. Longitudinal axis: An axis extending along the length of a shape. The axis generally passes through a center of the shape. c. Circumferential axis: An axis oriented perpendicularly with respect to the longitudinal axis. The axis may be specifically present in pipes, tubes, cylinders, or similar shapes with a circular and/or elliptical cross section.

[0515] Deformation: The process where the original geometry of a member changes when subjected to forces, e.g. a force in a direction with respect to an axis. The process may include stretching or compressing, bending and, twisting.

[0516] Elasticity: The ability of a material to return to its original geometry after deformation. [0517] Floppy structure or component: A structure or component that will change shape, e.g. bend, when caused to support its own weight, within a relatively short period of time such as 1 second.

[0518] Resilience: Ability of a material to absorb energy when deformed elastically and to release the energy upon unloading.

[0519] Resilient: Will release substantially all of the energy when unloaded. Includes e.g. certain silicones, and thermoplastic elastomers.

[0520] Rigid structure or component: A structure or component that will not substantially change shape when subject to the loads typically encountered in use. An example of such a use may be setting up and maintaining a patient interface in sealing relationship with an entrance to a patient's airways, e.g. at a load of approximately 20 to 30 cmH20 pressure.

[0521] As an example, an I-beam may comprise a different bending stiffness (resistance to a bending load) in a first direction in comparison to a second, orthogonal direction. In another example, a structure or component may be floppy in a first direction and rigid in a second direction.

[0522] Stiffness (or rigidity) of a structure or component: The ability of the structure or component to resist deformation in response to an applied load. The load may be a force or a moment, e.g. compression, tension, bending or torsion. The structure or component may offer different resistances in different directions. The inverse of stiffness is flexibility.

[0523] Viscous: The ability of a material to resist flow.

[0524] Visco-elasticity: The ability of a material to display both elastic and viscous behaviour in deformation.

[0525] Yield: The situation when a material can no longer return back to its original geometry after deformation.

5.9.1.3 Structural Elements

[0526] Compression member: A structural element that resists compression forces.

[0527] Elbow: An elbow is an example of a structure that directs an axis of flow of air travelling therethrough to change direction through an angle. In one form, the angle may be approximately 90 degrees. In another form, the angle may be more, or less than 90 degrees. The elbow may have an approximately circular cross-section. In another form the elbow may have an oval or a rectangular cross-section. In certain forms an elbow may be rotatable with respect to a mating component, e.g. about 360 degrees. In certain forms an elbow may be removable from a mating component, e.g. via a snap connection. In certain forms, an elbow may be assembled to a mating component via a one-time snap during manufacture, but not removable by a patient. [0528] 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 structure in the mask. However, some forms of mask frame may also be air-tight.

[0529] 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. [0530] Tie (noun)-. A structure designed to resist tension.

[0531] Thin structures: a. Beams, i. A beam may be relatively long in one dimension compared to the other two dimensions such that the smaller dimensions are comparatively thin compared to the long dimension b. Membranes, i. Relatively long in two dimensions, with one thin dimension. Readily deforms in response to bending forces. Resists being stretched, (might also resist compression). c. Plates & Shells i. These may be relatively long in two directions, with one thin dimension. They may have bending, tensile, and/or compressive stiffness.

[0532] Thick structures: Solids

[0533] Seal: May be a noun form ("a seal") which refers to a structure, or a verb form (“to seal”) which refers to the effect. Two elements may be constructed and/or arranged to ‘seal’ or to effect ‘sealing’ therebetween without requiring a separate ‘seal’ element per se. [0534] 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.

[0535] Stiffener: A stiffener will be taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0536] 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.

[0537] 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 through 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 delivery 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.

5.9.2 Respiratory cycle

[0538] Apnea-. According to some definitions, 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 occurred when, despite patient effort, some obstruction of the airway does not allow air to flow. A central 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 absence of breathing effort coincides with an obstructed airway.

[0539] Breathing rate-. The rate of spontaneous respiration of a patient, usually measured in breaths per minute.

[0540] Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

[0541] Effort (breathing): The work done by a spontaneously breathing person attempting to breathe.

[0542] Expiratory portion of a breathing cycle: The period from the start of expiratory flow to the start of inspiratory flow.

[0543] Flow limitation: 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 limitation. Where flow limitation occurs during an expiratory portion of the breathing cycle it may be described as expiratory flow limitation.

[0544] Inspiratory portion of a breathing cycle: The period from the start of inspiratory flow to the start of expiratory flow will be taken to be the inspiratory portion of a breathing cycle.

[0545] 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).

[0546] Ventilation (Vent): A measure of a rate 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 volume, understood to be the volume per minute.

5.9.3 Anatomy

5.9.3.1 Anatomy of the face

[0547] Ala: the external outer wall or "wing" of each nostril (plural: alar) [0548] Alar angle: An angle formed between the ala of each nostril.

[0549] Alare: The most lateral point on the nasal ala.

[0550] 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.

[0551] Auricle: The whole external visible part of the ear.

[0552] (nose) Bony framework: The bony framework of the nose comprises the nasal bones, the frontal process of the maxillae and the nasal part of the frontal bone.

[0553] (nose) Cartilaginous framework: The cartilaginous framework of the nose comprises the septal, lateral, major and minor cartilages.

[0554] Columella: the strip of skin that separates the nares and which runs from the pronasale to the upper lip.

[0555] Columella angle: The angle between the line drawn through the midpoint of the nostril aperture and a line drawn perpendicular to the Frankfort horizontal while intersecting subnasale.

[0556] Frankfort 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.

[0557] Glabella: Located on the soft tissue, the most prominent point in the midsagittal plane of the forehead.

[0558] Lateral nasal cartilage: A generally triangular plate of cartilage. Its superior margin is attached to the nasal bone and frontal process of the maxilla, and its inferior margin is connected to the greater alar cartilage.

[0559] Lip, lower (labrale inferius): The lip extending between the subnasale and the mouth.

[0560] Lip, upper (labrale superius): The lip extending between the mouth and the supramenton.

[0561] Greater alar cartilage: A plate of cartilage lying below the lateral 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 membrane containing three or four minor cartilages of the ala.

[0562] Nares (Nostrils): Approximately ellipsoidal apertures forming the entrance to the nasal cavity. The singular form of nares is naris (nostril). The nares are separated by the nasal septum.

[0563] 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. [0564] Naso-labial angle: The angle between the columella and the upper lip, while intersecting subnasale. [0565] Otobasion inferior: The lowest point of attachment of the auricle to the skin of the face.

[0566] Otobasion superior: The highest point of attachment of the auricle to the skin of the face.

[0567] 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.

[0568] Philtrum: the midline groove that runs from lower border of the nasal septum to the top of the lip in the upper lip region.

[0569] Pogonion: Located on the soft tissue, the most anterior midpoint of the chin.

[0570] Ridge (nasal): The nasal ridge is the midline prominence of the nose, extending from the Sellion to the Pronasale.

[0571] Sagittal plane: A vertical plane that passes from anterior (front) to posterior (rear). The midsagittal plane is a sagittal plane that divides the body into right and left halves. [0572] Sellion: Located on the soft tissue, the most concave point overlying the area of the frontonasal suture.

[0573] Septal cartilage (nasal): The nasal septal cartilage forms part of the septum and divides the front part of the nasal cavity.

[0574] Subalare: The point at the lower margin of the alar base, where the alar base joins with the skin of the superior (upper) lip.

[0575] Subnasal point: Located on the soft tissue, the point at which the columella merges with the upper lip in the midsagittal plane.

[0576] Supramenton: The point of greatest concavity in the midline of the lower lip between labrale inferius and soft tissue pogonion

[0577] Anatomy of the skull

[0578] Frontal bone: The frontal bone includes a large vertical portion, the squama frontalis, corresponding to the region known as the forehead.

[0579] Mandible: The mandible forms the lower jaw. The mental protuberance is the bony protuberance of the jaw that forms the chin.

[0580] Maxilla: The maxilla forms the upper jaw and is located above the mandible and below the orbits. The frontal process of the maxilla projects upwards by the side of the nose, and forms part of its lateral boundary.

[0581] 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 junction, the "bridge" of the nose.

[0582] Nasion: 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. [0583] Occipital bone: The occipital bone is situated at the back and lower part of the cranium. It includes an oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal. The curved plate behind the foramen magnum is the squama occipitalis.

[0584] Orbit: The bony cavity in the skull to contain the eyeball.

[0585] Parietal bones: The parietal bones are the bones that, when joined together, form the roof and sides of the cranium.

[0586] 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.

[0587] 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.

S.9.3.2 Anatomy of the respiratory system

[0588] Diaphragm: A sheet of muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity, containing the heart, lungs and ribs, from the abdominal cavity. As the diaphragm contracts the volume of the thoracic cavity increases and air is drawn into the lungs.

[0589] Larynx: The larynx, or voice box houses the vocal folds and connects the inferior part of the pharynx (hypopharynx) with the trachea.

[0590] 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 alveolar ducts, and the alveoli.

[0591] 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 conchae (singular "concha") or turbinates. To the front of the nasal cavity is the nose, while the back blends, via the choanae, into the nasopharynx.

[0592] Pharynx: The part of the throat situated immediately inferior to (below) the nasal cavity, and superior to the oesophagus and larynx. The pharynx is conventionally divided into three sections: the nasopharynx (epipharynx) (the nasal part of the pharynx), the oropharynx (mesopharynx) (the oral part of the pharynx), and the laryngopharynx (hypopharynx).

5.9.4 Patient interface

[0593] 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 rebreathing by a patient.

[0594] Headgear: Headgear will be taken to mean a form of positioning and stabilising structure designed to hold a device, e.g., a mask, on a head. [0595] 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 pressure in use. A shell may form part of the walls of a mask plenum chamber.

[0596] Seal: May be a noun form ("a seal") which refers to a structure, or a verb form (“to seal”) which refers to the effect. Two elements may be constructed and/or arranged to ‘seal’ or to effect ‘sealing’ therebetween without requiring a separate ‘seal’ element per se. [0597] Vent: (noun): A structure that allows a flow of air from an interior of the mask, or conduit, to ambient air for clinically effective washout of exhaled gases. For example, a clinically effective washout may involve a flow rate of about 10 litres per minute to about 100 litres per minute, depending on the mask design and treatment pressure.

5.9.5 Shape of structures

[0598] Products in accordance with the present technology may comprise one or more three-dimensional mechanical structures, for example a mask cushion or an impeller. The three-dimensional structures may be bounded by two-dimensional surfaces. These surfaces may be distinguished using a label to describe an associated surface orientation, location, function, or some other characteristic. For example a structure may comprise one or more of an anterior surface, a posterior surface, an interior surface and an exterior surface. In another example, a seal-forming structure 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.

[0599] 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.

5.9.5.1 Curvature in one dimension

[0600] 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). [0601] 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. [0602] 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.

[0603] Negative curvature: 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.

S.9.5.2 Curvature of two dimensional surfaces

[0604] A description of the shape at a given point on a two-dimensional surface in accordance with the present technology may include multiple normal cross-sections. The multiple cross-sections may cut the surface in a plane that includes the outward normal (a “normal plane”), and each cross-section may be taken in a different direction. Each crosssection 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 magnitude, e.g. relatively small. The plane curves in Figs. 3B to 3F could be examples of such multiple cross-sections at a particular point.

[0605] Principal curvatures and directions: The directions of the normal planes where the curvature of the curve takes its maximum and minimum values are called the principal directions. In the examples of Fig. 3B to Fig. 3F, the maximum 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.

[0606] Region of a surface: A connected set of points on a surface. The set of points in a region may have similar characteristics, e.g. curvatures or signs.

[0607] Saddle region: 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).

[0608] 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 “convex dome”).

[0609] 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. [0610] Planar region: A region of a surface where both of the principal curvatures are zero (or, for example, zero within manufacturing tolerances).

[0611] Edge of a surface: A boundary or limit of a surface or region.

[0612] 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(l) on a surface. In certain forms of the present technology, a ‘path’ may be described as a route or course, including e.g. a set of points on a surface. (The path for the imaginary person is where they walk on the surface, and is analogous to a garden path).

[0613] Path length: In certain forms of the present technology, ‘path length’ will be taken to mean the distance along the surface from f(0) to f(l), 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).

[0614] 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 distance 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’.)

S.9.5.3 Space curves

[0615] Space curves: Unlike a plane curve, a space curve does not necessarily lie in any particular plane. A space curve may be closed, that is, having no endpoints. A space curve may be considered to be a one-dimensional piece of three-dimensional space. An imaginary person walking on a strand of the DNA helix walks along a space curve. A typical human left ear comprises a helix, which is a left-hand helix, see Fig. 3Q. A typical human right ear comprises a helix, which is a right-hand helix, see Fig. 3R. Fig. 3S shows a right-hand helix. The edge of a structure, e.g. the edge of a membrane or impeller, may follow a space curve. In general, a space curve may be described by a curvature and a torsion at each point on the space curve. Torsion is a measure of how the curve turns out of a plane. Torsion has a sign and a magnitude. The torsion at a point on a space curve may be characterised with reference to the tangent, normal and binormal vectors at that point.

[0616] Tangent unit vector (or unit tangent vector): For each point on a curve, a vector at the point specifies a direction from that point, as well as a magnitude. A tangent unit vector is a unit vector pointing in the same direction as the curve at that point. If an imaginary person were flying along the curve and fell off her vehicle at a particular point, the direction of the tangent vector is the direction she would be travelling.

[0617] Unit normal vector: As the imaginary person moves along the curve, this tangent vector itself changes. The unit vector pointing in the same direction that the tangent vector is changing is called the unit principal normal vector. It is perpendicular to the tangent vector. [0618] Binormal unit vector: The binormal unit vector is perpendicular to both the tangent vector and the principal normal vector. Its direction may be determined by a righthand rule (see e.g. Fig. 3P), or alternatively by a left-hand rule (Fig. 30). [0619] Osculating plane: The plane containing the unit tangent vector and the unit principal normal vector. See Figures 30 and 3P.

[0620] Torsion of a space curve: The torsion at a point of a space curve is the magnitude of the rate of change of the binormal unit vector at that point. It measures how much the curve deviates from the osculating plane. A space curve which lies in a plane has zero torsion. A space curve which deviates a relatively small amount from the osculating plane will have a relatively small magnitude of torsion (e.g. a gently sloping helical path). A space curve which deviates a relatively large amount from the osculating plane will have a relatively large magnitude of torsion (e.g. a steeply sloping helical path). With reference to Fig. 3S, since T2>T1, the magnitude of the torsion near the top coils of the helix of Fig. 3S is greater than the magnitude of the torsion of the bottom coils of the helix of Fig. 3S

[0621] With reference to the right-hand rule of Fig. 3P, a space curve turning towards the direction of the right-hand binormal may be considered as having a right-hand positive torsion (e.g. a right-hand helix as shown in Fig. 3S). A space curve turning away from the direction of the right-hand binormal may be considered as having a right-hand negative torsion (e.g. a left-hand helix).

[0622] Equivalently, and with reference to a left-hand rule (see Fig. 30), a space curve turning towards the direction of the left-hand binormal may be considered as having a lefthand positive torsion (e.g. a left-hand helix). Hence left-hand positive is equivalent to righthand negative. See Fig. 3T.

S.9.5.4 Holes

[0623] A surface may have a one-dimensional hole, e.g. a hole bounded by a plane curve or by a space curve. Thin structures (e.g. a membrane) with a hole, may be described as having a one-dimensional hole. See for example the one dimensional hole in the surface of structure shown in Fig. 31, bounded by a plane curve.

[0624] A structure may have a two-dimensional hole, e.g. a hole bounded by a surface. For example, an inflatable tyre has a two dimensional hole bounded by the interior surface of the tyre. In another example, a bladder with a cavity for air or gel could have a two- dimensional hole. See for example the cushion of Fig. 3L and the example cross-sections therethrough in Fig. 3M and Fig. 3N, with the interior surface bounding a two dimensional hole indicated. In a yet another example, a conduit may comprise a one-dimension hole (e.g. at its entrance or at its exit), and a two-dimension hole bounded by the inside surface of the conduit. See also the two dimensional hole through the structure shown in Fig. 3K, bounded by a surface as shown.

5.10 OTHER REMARKS

[0625] 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 reserves all copyright rights whatsoever.

[0626] Unless the context 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 intervening 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 intervening ranges, 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.

[0627] 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 significant digit to the extent that a practical technical implementation may permit or require it.

[0628] Furthermore, “approximately”, “substantially”, “about”, or any similar term used herein means +/- 5-10% of the recited value.

[0629] 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.

[0630] When a particular material is identified as being used to construct a component, obvious alternative materials with similar properties may be used as a substitute. Furthermore, unless specified 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.

[0631] It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include their plural equivalents, unless the context clearly dictates otherwise.

[0632] All publications mentioned herein are incorporated herein by reference in their entirety to disclose and describe the methods and/or materials 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 different from the actual publication dates, which may need to be independently confirmed.

[0633] The terms "comprises" and "comprising" 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.

[0634] The subject headings used in the detailed description are included only for the ease of reference of the reader and should not be used to limit the subject 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.

[0635] 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 utilised to distinguish between distinct 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.

[0636] It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the technology.

5.11 REFERENCE SIGNS LIST

Claims

6 CLAIMS

1. A patient interface constructed and arranged to form a seal with a region of the patient’s face, including a nose bridge region, and surrounding an entrance to the patient’s airways, the patient interface including: a plenum chamber defined, at least in part, by a chassis portion, wherein at least a portion of a perimeter of the chassis portion comprises a flange, and wherein at least the portion of the chassis portion, including the flange, is relatively flexible, a seal-forming structure, wherein the seal forming structure includes a textile layer, wherein the textile layer has a patient-contacting side and non-patient contacting side, and wherein the non-patient contacting side of the textile layer is bonded or otherwise secured to the flange such that, in use, the patientcontacting side of the textile layer contacts the patient’s face; and wherein the perimeter of the chassis portion includes a cutout, which in use corresponds to at least the nose bridge region of the patient’s face, wherein the textile layer covers the cutout.

2. The patient interface of claim 1, wherein the chassis portion is made from a material having a Shore A hardness of between 30 and 60.

3. The patient interface of claim 1 or 2, wherein the cutout extends to an anterior wall of the chassis portion.

4. The patient interface of claim 1, 2 or 3, wherein the portion of the cutout in the anterior wall of the chassis portion has a substantially inverted teardrop or inverted triangle shape.

5. The patient interface of any one of claims 1 to 4, wherein no flange is provided to the cutout.

6. The patient interface of any one of claims 1 to 5, wherein the flange terminates at sides of nose portions which are configured to engage portions of the sides of the patient’s nose corresponding to the nasal bone.

7. The patient interface of claim 6, wherein the sides of nose portions are configured to avoid engagement with the portion of the patient’s nose corresponding to the greater alar cartilage.

8. The patient interface of claim 6 or 7, wherein the sides of nose portions are configured to avoid engagement with the portion of the patient’s nose corresponding to the septum cartilage.

9. The patient interface of any one of the preceding claims, wherein the flange curves inward.

10. The patient interface of claim 9, wherein the flange has a substantially “C” shape profile.

11. The patient interface of claim 9 or 10, wherein a curvature of the flange is substantially continuous with a curvature of an immediately adjacent portion of the chassis portion.

12. The patient interface of any one of the preceding claims, wherein the flange has a thickness of between 2.5mm and 0.5mm.

13. The patient interface of any one of the preceding claims, wherein the flange has a free edge.

14. The patient interface of claim 13, wherein the thickness of the flange tapers down toward the free edge.

15. The patient interface of claim 13 or 14, wherein at least portions of the textile layer extend beyond the free edge of the flange to form at least one unsupported portion of the textile layer.

16. The patient interface of claim 15, wherein the unsupported portion of the textile layer has a uniform width.

17. The patient interface of claim 16, wherein the unsupported portion has a width of substantially 2mm.

18. The patient interface of claim 15, wherein the textile layer comprises unsupported portions having varying widths.

19. The patient interface of any one of the preceding claims, wherein the textile layer is formed from a single piece of textile.

20. The patient interface of any one of the preceding claims, wherein the textile layer is cut from a flat sheet of textile.

21. The patient interface of any one of the preceding claims, wherein the textile layer comprises a stretchable material.

22. The patient interface of any one of the preceding claims, wherein the textile layer is substantially impermeable to air.

23. The patient interface of any one of claims 1 to 21, wherein one or more regions of, or all of, the textile layer allow a limited flow of air.

24. The patient interface of any one of the preceding claims, wherein the textile layer comprises a thin layer of elastomer.

25. The patient interface of any one of the preceding claims, wherein the textile layer comprises a main portion, a superior portion, and a necked portion between the main and superior portions.

26. The patient interface of claim 25, wherein the necked portion of the textile layer forms a nasal bridge sealing portion.

27. The patient interface of claim 26, wherein the nasal bridge sealing portion has a concave shape.

28. The patient interface of any one of the preceding claims, wherein at least a portion of the flange is not covered by the textile layer, and wherein the portion of the flange which is not covered by the textile layer is configured to seal against the patient’s face.

29. The patient interface of any one of the preceding claims, wherein the chassis portion comprises a shell portion which is more rigid than the remainder of the chassis portion.

30. The patient interface of claim 29, wherein the shell portion does not extend to the lateral or inferior walls of the chassis portion.

31. The patient interface of claim 29 or 30, wherein the shell portion has a Shore A hardness of greater than 60.

32. The patient interface of claim 29, 30 or 31, wherein the shell portion is made from a nylon, a polyester, a semi-rigid elastomer, or silicone.

33. The patient interface of any one of claims 29 to 32, wherein the shell portion forms at least part of an anterior wall of the chassis portion.

34. The patient interface of any one of claims 29 to 33, wherein the cutout extends to the shell portion.

35. The patient interface of any one of claims 29 to 34, wherein the anterior wall of the chassis portion comprises a layer of relatively flexible material with the shell portion connected to an outer surface of the relatively flexible material.

36. A patient interface constructed and arranged to form a seal with a region of the patient’s face, including a nose bridge region, and surrounding an entrance to the patient’s airways, the patient interface including: a plenum chamber, wherein the plenum chamber comprises a chassis having a perimeter and wherein a posterior/interior side of the chassis defines an air chamber, and wherein a portion of the perimeter is configured with a flange; a seal-forming structure, wherein the seal forming structure includes a foam layer, wherein the foam layer has an anterior side and a posterior side, and wherein the anterior side is bonded or otherwise secured to the patient-contacting side of the flange of the chassis, the seal-forming structure also including a textile layer, wherein the textile layer has a patient-contacting surface and non-patient contacting surface, and wherein the bonding surface of the textile layer is bonded or otherwise secured to the patient-contacting side of the foam layer such that, in use, the patient-contacting surface contacts a patient’s face; and wherein the perimeter of the chassis includes a cut out, which in use, corresponds to the nose bridge region of the patient’s face.

37. The patient interface of claim 36, wherein the chassis of the plenum chamber is rigid or semi-rigid.

38. The patient interface of claim 36 or 37, wherein the chassis of the plenum chamber is configured to receive one of: a connector for an air circuit; an air circuit, or decoupling structure.

39. The patient interface of any one of claims 36 to 38, wherein the chassis of the plenum chamber is configured to receive a frame on an anterior/exterior surface.

40. The patient interface of any one of claims 36 to 39, wherein the flange of the chassis extends inwards of the air chamber.

41. The patient interface of any one of claims 36 to 40, wherein the flange terminates at or proximate the cut out of the chassis.

42. The patient interface of any one of claims 36 to 41, wherein the flange of the chassis has a posterior side.

43. The patient interface of claim 42, wherein the anterior side of the foam layer of the seal-forming structure is adhesively bonded or otherwise secured to the posterior side of the flange.

44. The patient interface of any one of claims 36 to 43, wherein the foam layer has an outer perimeter that is flush with the outer perimeter of the chassis when secured to the flange.

45. The patient interface of any one of claims 36 to 44, wherein a width dimension of the foam layer is greater than a width dimension of the flange.

46. The patient interface of any one of claims 36 to 45, wherein the textile layer is adhesively bonded or otherwise secured to the posterior side of the foam layer.

47. The patient interface of any one of claims 36 to 46, wherein the textile layer includes an integral superior portion arranged and/or configured to be folded over and cover the cut out of the chassis.

48. The patient interface of any one of claims 36 to 47, wherein at least a portion of the patient contacting side of the superior portion of the textile layer covers, in use, the cut out of the chassis.

49. The patient interface of any one of claims 36 to 46, wherein the textile layer includes a separate superior portion configured to be adhesively bonded, welded or otherwise secured to the chassis to cover the cut out of the chassis.

50. The patient interface of claim 49, wherein the superior portion of the textile layer is mechanically secured to the cut out of the chassis.

51. The patient interface of any one of claims 36 to 50, wherein the textile layer is arranged to, in use, apply a tensile force to the nose bridge region of the patient.

52. The patient interface of any one of claims 36 to 51, wherein the textile layer is impermeable to air.

53. The patient interface of any one of claims 36 to 52, wherein the non-patient contacting surface of the textile is coated with a layer or membrane of silicone.

54. The patient interface of any one of claims 36 to 53, wherein the chassis of the plenum chamber includes a second cut out, which in use, corresponds to the chin/lip inferior/supramenton region of the patient’s face.

55. The patient interface of claim 54, wherein the flange terminates at or proximate the second cut out of the chassis.

56. The patient interface of claim 54 or 55, wherein the foam layer spans the second cut out.

57. The patient interface of claims 54, 55, or 56, wherein the textile layer includes an integral inferior portion arranged and/or configured to be folded over and cover the second cut out of the chassis.

58. The patient interface of claims 54, 55, or 56, wherein the textile layer is adhesively bonded, welded or otherwise secured to the chassis to cover the second cut out of the chassis.

59. The patient interface of claims 54, 55, or 56, wherein the textile layer includes a separate inferior portion configured to be adhesively bonded or otherwise secured to the chassis to cover the second cut out of the chassis.

60. The patient interface of claim 59, wherein the inferior portion of the textile layer is mechanically secured to the second cut out of the chassis.

61. The patient interface of any of claims 1 to 60, wherein the patient interface is one of: an ora-nasal mask or a nasal mask.

62. The patient interface of any of claims 1 to 61, wherein the patient interface includes a positioning and stabilising structure configured and arranged to maintain the seal-forming structure in a substantially sealing relation with the appropriate portion of the face of a patient.