NZ767507A

NZ767507A - A medical humidifier

Info

Publication number: NZ767507A
Application number: NZ767507A
Authority: NZ
Inventors: Ronald James Huby; Roger Mervyn Lloyd Foote; Quangang Yang; Dmitri Anatolievich Doudkine; Zhuo Ran Tang; Matthew Rolf Harrington
Original assignee: ResMed Pty Ltd
Priority date: 2014-03-13
Filing date: 2014-09-11
Publication date: 2022-03-25

Abstract

A method for controlling a location and/or a rate of foreign matter build-up on a humidifier wick (5230) of a humidifier (5000), the humidifier including the humidifier wick, a heating element (5220) to apply heat to the humidifier wick, a water delivery mechanism to deliver water to the humidifier wick, and a controller configured to receive one more signals and/or generate one or more signals, the humidifier wick being configured to retain a volume of water. The method includes controlling a location and/or a pattern of a water boundary on the humidifier wick of the humidifier by varying, with the controller, at least one of: a heat output from the heating element onto the humidifier wick; a water flow rate from the water delivery mechanism onto the humidifier wick; and a water distribution pattern within the humidifier wick by adjusting the heat output from the heating element and/or the water flow rate from the water delivery. Controlling the location and/or the pattern of the water boundary causes foreign matter to build up at a predetermined region of the humidifier wick based on the location and/or the pattern of the water boundary.

Description

A MEDICAL HUMIDIFIER 1 CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable 2 OUND OF THE TECHNOLOGY 2.1 FIELD OF THE TECHNOLOGY The present technology relates to one or more of the detection, sis, treatment, prevention and amelioration of respiratory-related disorders. In particular, the present technology relates to medical devices or apparatus, and their use. 2.2 DESCRIPTION OF THE RELATED ART 2.2.1 Human Respiratory System The respiratory system of the body facilitates gas exchange. The nose and mouth form the entrance to the s of a patient.

The airways include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the air into the venous blood and carbon dioxide to move out. The trachea divides into right and left main bronchi, which further divide ally 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 2011.

A range of respiratory disorders exist.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing (SDB), is characterized by occlusion or obstruction of the upper air passage during sleep. It s from a ation of an ally small upper airway and the normal loss of muscle tone in the region of the , soft palate and posterior 505809DIV4 oropharyngeal wall during sleep. The condition causes the affected patient to stop breathing for periods typically of 30 to 120 seconds duration, sometimes 200 to 300 times per night. It often causes excessive e somnolence, and it may cause cardiovascular disease and brain . The syndrome is a common disorder, particularly in middle aged overweight males, although a person affected may have no awareness of the problem. See US Patent 4,944,310 (Sullivan).

Cheyne-Stokes ation (CSR) is a disorder of a patient's respiratory ller in which there are rhythmic alternating periods of waxing and waning ventilation, causing 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 tion, increased hetic activity, and sed afterload. See US Patent 6,532,959 (Berthon-Jones). y Hyperventilation Syndrome (OHS) is d 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.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a group of lower airway diseases that have certain teristics in common. These include increased resistance to air movement, extended expiratory phase of respiration, and loss of the normal city 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.

Neuromuscular Disease (NMD) is a broad term that asses many diseases and ailments that impair the functioning of the muscles either directly via intrinsic muscle pathology, or indirectly via nerve ogy. 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 ssive: (i) Rapidly progressive disorders: 505809DIV4 terised 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 phy). Symptoms of respiratory failure in NMD include: increasing generalised weakness, dysphagia, dyspnea on on and at rest, fatigue, sleepiness, morning headache, and difficulties with concentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result in inefficient coupling between the respiratory muscles and the thoracic cage. The disorders are y characterised by a restrictive defect and share the potential of long term apnic respiratory failure. Scoliosis and/or kyphoscoliosis may cause severe respiratory failure. Symptoms of respiratory e include: dyspnea on exertion, peripheral oedema, nea, repeated chest infections, morning headaches, e, poor sleep quality and loss of appetite.

Otherwise healthy individuals may take advantage of s and s to prevent respiratory disorders from arising. 2.2.2 Therapy Nasal Continuous Positive Airway Pressure (CPAP) therapy has been used to treat Obstructive Sleep Apnea (OSA). The hypothesis is that continuous positive airway pressure acts as a pneumatic splint and may prevent upper airway occlusion by pushing the soft palate and tongue d and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) provides ventilatory support to a patient through the upper airways to assist the patient in taking a full breath 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 patient interface. NIV has been used to treat CSR, OHS, COPD, MD and Chest Wall disorders. 505809DIV4 Invasive ventilation (IV) provides ventilatory support to patients that are no longer able to effectively breathe themselves and is ed using a tracheostomy tube. ators may control the timing and pressure of breaths pumped into the patient and monitor the breaths taken by the patient. The methods of control and monitoring patients typically include volume-cycled and pressure-cycled methods.

The volume-cycled methods may include among others, Pressure-Regulated Volume Control (PRVC), Volume Ventilation (VV), and Volume Controlled Continuous Mandatory Ventilation (VC-CMV) techniques. The pressure-cycled methods may involve, among others, Assist Control (AC), onized Intermittent Mandatory Ventilation (SIMV), Controlled Mechanical Ventilation (CMV), re Support Ventilation (PSV), Continuous Positive Airway Pressure (CPAP), or Positive End Expiratory Pressure (PEEP) techniques. 2.2.3 Systems A system may comprise an RPT device, an air circuit, a humidifier, a patient interface, and data management. 2.2.4 Patient Interface A patient interface may be used to interface respiratory equipment to its user, for example by providing a flow of air. 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 the user. Depending upon the therapy to be applied, the t interface may form a seal, e.g. with a face region of the patient, to facilitate the delivery of gas at a pressure at sufficient variance with ambient pressure to effect therapy, e.g. a positive pressure of about O. For other forms of therapy, such as the delivery of , the t interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about O.

The design of a t interface presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of noses varies considerably between duals. Since the head includes bone, cartilage and soft tissue, different regions of the face respond differently to mechanical forces. The jaw 505809DIV4 or mandible may move relative to other bones of the skull. The whole head may move during the course of a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being one or more of obtrusive, aesthetically undesirable, costly, poorly g, difficult to use, and uncomfortable especially when worn for long periods of time or when a patient is unfamiliar with a system. For example, masks designed solely for aviators, mask 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 be undesirably uncomfortable to be worn for extended s of time, e.g. several hours. This is even more so if the mask is to be worn during sleep.

Nasal CPAP therapy is highly effective to treat n 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 ult to clean (e.g. difficult to assemble or disassemble), patients may not clean their mask and this may impact on patient compliance.

While a mask for other ations (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.

For these reasons, masks for delivery of nasal CPAP during sleep form a distinct field. 2.2.5 Respiratory Pressure Therapy (RPT) Device Examples of RPT devices include ResMed’s S9 AutoSetTM PAP device and ResMed’s Stellar™ 150 ator. RPT devices typically se a pressure generator, such as a driven blower or a compressed gas reservoir, and are configured to supply a flow of air to the airway of a patient. In some cases, the flow of air may be supplied to the airway of the patient at positive pressure. The outlet of the RPT device is connected via an air circuit to a patient interface such as those 505809DIV4 described above. In some cases, RPT s have been known to be referred to as flow generators.

RPT devices typically include a re generator, an inlet filter, a patient interface, an air circuit connecting the pressure generator to the patient ace, various sensors and a microprocessor-based controller. The patient interface may e a mask or a tracheostomy tube as described above. The pressure generator may include a servo-controlled motor, volute and an impeller. In some cases a brake for the motor may be implemented to more rapidly reduce the speed of the blower so as to me the a of the motor and impeller. The braking can permit the blower to more rapidly achieve a lower pressure condition in time for synchronization with exhalation despite the inertia. In some cases the pressure generator may also include a valve capable of discharging generated air to atmosphere as a means for altering the re red to the patient as an alternative to motor speed control. The sensors may measure, amongst other things, motor speed, air flow rate and outlet pressure, such as with a pressure transducer or the like. The controller may include data storage capacity with or without integrated data retrieval and display functions.

Table of noise output levels of prior devices (one specimen only, measured using test method specified in ISO3744 in CPAP mode at 10cmH2O).

Device name A-weighted sound power Year (approx.) level dB(A) C-Series Tango 31.9 2007 C-Series Tango with Humidifier 33.1 2007 S8 Escape II 30.5 2005 S8 Escape II with H4i Humidifier 31.1 2005 S9 AutoSet 26.5 2010 S9 AutoSet with H5i Humidifier 28.6 2010 2.2.6 fier Delivery of a flow of air without humidification may cause drying of airways. Medical humidifiers are used to increase absolute humidity and/or temperature of the flow of air in relation to ambient air when required, typically 505809DIV4 where the patient may be asleep or resting (e.g. at a hospital). As a , a medical humidifier is preferably small for bedside placement, and it is preferably ured to only humidify and/or heat the flow of air red to the patient without humidifying and/or heating the patient’s surroundings. Room-based systems (e.g. a sauna, an air conditioner, an evaporative ), for example, may also humidify air that is breathed in by the patient, however they would also humidify and/or heat the entire room, which may cause discomfort to the occupants.

The use of a humidifier with a pressure generator or RPT device and the t interface produces humidified gas that minimizes drying of the nasal mucosa and increases t airway comfort. In addition in cooler climates, warm air d generally to the face area in and about the patient interface is more comfortable than cold air.

Respiratory humidifiers are available in many forms and may: be a standalone device that is coupled to an RPT device via an air conduit, is integrated with the RPT device, or be configured to be directly coupled to the relevant RPT device. While known passive humidifiers can provide some relief, generally a heated humidifier may be used to provide sufficient ty and temperature to the air so that the patient will be comfortable. Humidifiers typically comprise a water reservoir or tub having a capacity of several hundred milliliters (ml), a heating t for heating the water in the reservoir, a control to enable the level of humidification to be varied, a gas inlet to receive gas from the RPT device, and a gas outlet adapted to be connected to an air circuit that delivers the humidified gas to the patient interface.

Heated passover humidification is one common form of humidification used with an RPT device. In such humidifiers the heating element may be orated in a heater plate which sits under, and is in thermal contact with, the water tub. Thus, heat is transferred from the heater plate to the water reservoir primarily by conduction. The air flow from the RPT device passes over the heated water in the water tub resulting in water vapour being taken up by the air flow. The ResMed H4i™ and H5i™ Humidifiers are examples of such heated passover humidifiers that are used in combination with ResMed S8 and S9 RPT devices respectively.

Other humidifiers may also be used such as a bubble or diffuser humidifier or a jet humidifier. In a bubble or diffuser humidifier the air is conducted below the surface of the water and allowed to bubble back to the top. A jet humidifier produces an aerosol of water and baffles or filters may be used so that the particles are either removed or evaporated before leaving the humidifier.

An alternative form of humidification is provided by the ResMed HumiCare™ D900 humidifier that uses a CounterStream™ technology that directs the air flow over a large surface area in a first direction whilst ing heated water to the large surface area in a second opposite ion. The ResMed HumiCare™ D900 humidifier may be used with a range of invasive and non-invasive ventilators. 3 BRIEF SUMMARY OF THE TECHNOLOGY The present technology is directed towards providing medical devices used in the diagnosis, amelioration, treatment, or prevention of respiratory disorders having one or more of improved comfort, cost, efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used in the diagnosis, amelioration, treatment or tion of a respiratory disorder.

Another aspect of the t technology relates to methods used in the diagnosis, amelioration, treatment or prevention of a atory disorder.

Another aspect of the present logy relates to a humidifier increasing an absolute humidity of a flow of air to be delivered to a patient’s airways, the humidifier comprising a water oir configured to retain a first volume of water, a humidifier chamber comprising an air inlet for receiving the flow of air, a water retention feature configured to retain a second volume of water, a heating element and an air outlet for delivering the flow of air, and a water delivery mechanism configured to deliver a flow of water from the water oir to the water ion feature wherein the heating element is configured to heat the water retention feature to se the second volume of water to add absolute humidity to the flow of air.

A further aspect of the present technology s to a humidifier wherein the water retention feature comprises a wick. 505809DIV4 A r aspect of the present logy relates to a humidifier wherein the water ion feature is coupled to a r.

A further aspect of the present logy relates to a carrier further comprising a grip surface.

A further aspect of the present technology relates to a humidifier wherein the humidifier further comprises an air flow baffle.

A further aspect of the present technology relates to a humidifier wherein the air flow baffle is coupled to the water retention feature.

A further aspect of the t technology s to a humidifier wherein the air flow baffle forces the air flow to travel along a helical path.

A further aspect of the present technology relates to a humidifier wherein the heating element ses a resistive electrical track.

A further aspect of the present technology relates to a humidifier n the resistive ical track is disposed on a circuit board.

A further aspect of the present technology relates to a humidifier wherein the circuit board is a flexible circuit board.

A further aspect of the present technology relates to a humidifier wherein the resistive ical track comprises one or more strands of resistive wire.

A further aspect of the present technology relates to a humidifier wherein the one or more strands of resistive wire forms a plurality of loops around a surface of the humidifier chamber.

A further aspect of the present logy relates to a heating element further comprising an adhesive for securing the plurality of loops.

A further aspect of the present technology relates to a humidifier further comprising one or more temperature sensors configured to measure one or more temperatures at the water retention feature. 505809DIV4 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 ed in various manners and also constitute additional aspects or sub-aspects of the present technology.

Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims. 4 BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE 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 r elements including: 4.1 TREATMENT SYSTEMS Fig. 1a shows a system including a t 1000 wearing a patient interface 3000, in the form of a nasal pillows, receives 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, a bed partner 1100 is also shown.

Fig. 1b shows a system ing a patient 1000 wearing a patient interface 3000, in the form of a nasal mask, receives 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.

Fig. 1c shows a system including a patient 1000 wearing a t ace 3000, in the form of a ace mask, receives 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. 505809DIV4 4.2 THERAPY 4.2.1 Respiratory system Fig. 2a shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, ar sacs, heart and agm.

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. 4.3 PATIENT INTERFACE Fig. 3 shows a patient interface 3000 in the form of a nasal mask in accordance with one form of the t technology. 4.4 RPT DEVICE Fig. 4a shows an exploded view of an RPT device 4000 in accordance with one form of the present logy.

Fig. 4b shows a schematic diagram of the pneumatic circuit of an RPT device 4000 in accordance with one form of the present logy. The directions of upstream and downstream are indicated.

Fig. 4c shows a schematic diagram of the electrical ents of an RPT device 4000 in accordance with one aspect of the present technology. 4.5 BREATHING WAVEFORMS Fig. 5 shows a model l breath waveform of a person while sleeping.

The horizontal axis is time, and the vertical axis is respiratory flow. While the 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, Qpeak, 0.4 L/s, exhalation time, Te, 2.4s, peak tory flow, 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 505809DIV4 (BPM), with Ventilation, Vent, about 7.5 L/minute. A typical duty cycle, the ratio of Ti to Ttot is about 40%. 4.6 HUMIDIFIER Fig. 6 shows one form of a prior art humidifier.

Fig. 7 shows a perspective view of a humidifier 5000 according to one aspect of the present technology.

Fig. 8 shows a schematic view of the humidifier of Fig. 7 r comprising a water delivery mechanism 5150 and a water reservoir 5110.

Fig. 9a shows a cross-section view in elevation of the humidifier of Fig. 7.

Fig. 9b shows a cross-section view in elevation of a fier 5000 according to an aspect of the present technology.

Fig. 10 shows an exploded perspective view of a portion of the humidifier 5000 of Fig. 7 g a humidifier wick 5230 and a wick frame 5232.

Fig. 11 shows a perspective view of one form of a heating element 5220 for a humidifier according to the present technology, the heating element comprising multiple heating zones.

Fig. 12 shows a cross-section view in elevation of a fier comprising a multiple layered wick 5230 ing to an aspect of the present technology.

Fig. 13 shows a perspective view of a humidifier wick 5230 according to an aspect of the present technology, the humidifier wick sing a corrugated inner surface.

Fig. 14 shows a cross-section view in ion of a humidifier 5000 showing a dry region 5230_D and a wet region 5230_W of the humidifier wick 5230 according to an aspect of the present technology.

Fig. 15 shows a section view in elevation of a humidifier 5000 including an arrangement of multiple humidifier transducers according to an aspect of the present technology. 505809DIV4 Fig. 16 shows a cross-section view in elevation of a humidifier including a temperature sensor 5514_5 ing to a further aspect of the present technology.

Fig. 17 shows an example of a relationship between a power output of a heating element and the humidity added to the flow of air by the humidifier.

Fig. 18 shows an example of a relationship between a temperature of a heating element and the humidity added to the flow of air by the fier.

Fig. 19 shows an e of a relationship between a power output of a heating element and the humidity added to the flow of air by the humidifier at various air flow rates.

Fig. 20 shows a ctive view of a humidifier 5000 according to one aspect of the present technology, wherein the heating element 5220 comprises resistive wires.

Fig. 21 shows a representation of example humidifier algorithms 5600 according to one aspect of the present technology.

Fig. 22 shows a art of an example algorithm 5610A of a wick condition determination algorithm according to one aspect of the present technology.

Fig. 23 shows a flowchart of another example thm 5610B of a wick condition ination algorithm according to one aspect of the present technology.

Fig. 24 shows a flowchart of another example algorithm 5610C of a wick condition determination algorithm according to one aspect of the t technology.

Fig. 25 shows a flowchart of an example algorithm 5620A of a plausibility check thm according to one aspect of the present technology.

DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY 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 505809DIV4 disclosure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting. .1 TREATMENT SYSTEMS In one form, the present technology comprises a system for treating a respiratory disorder. For example, a system may se an RPT device 4000, a humidifier 5000, an air circuit 4170 and a patient interface 3000. .2 THERAPY In one form, the present logy comprises a method for treating a respiratory disorder comprising the step of applying positive pressure to the ce of the s of a patient 1000. .2.1 Nasal CPAP for OSA In one form, the present technology comprises a method of ng Obstructive Sleep Apnea in a t by applying nasal continuous positive airway pressure to the patient.

In n embodiments 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. .3 PATIENT INTERFACE 3000 A non-invasive patient ace 3000 in accordance with one aspect of the present technology comprises the following onal aspects (e.g. as shown in Fig. 3): a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300 and a connection port 3600 for connection to air circuit 4170. The patient interface 3000 may further comprise a forehead support 3700 in some forms such as that shown in Fig. 3. 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 facilitate the supply of air at ve pressure to the airways. 505809DIV4 .4 RPT device 4000 A preferred RPT device 4000 in accordance with one aspect of the present logy comprises ical and pneumatic components 4100, electrical components 4200 and is programmed to execute one or more algorithms. The RPT device (e.g. as shown in Fig. 4a) preferably has an external housing 4010, for example formed in two parts, an upper portion 4012 and a lower portion 4014. Furthermore the external housing 4010 may e one or more panel(s) 4015. Preferably the RPT device 4000 comprises a chassis 4016 that supports one or more internal components of the RPT device 4000. In one form a pneumatic block 4020 is supported by, or formed as part of the chassis 4016. The RPT device 4000 may include a handle 4018.

The pneumatic path of the RPT device 4000 (e.g. as shown in Fig. 4b) may comprise an inlet air filter 4112, an inlet muffler 4122, a pressure device 4140 capable of supplying air at positive pressure (preferably a blower 4142), and an outlet muffler 4124. One or more ucers 4270, such as pressure sensors 4272 and flow sensors 4274, may be included in, or coupled with, the tic path.

The pneumatic block 4020 may comprise a portion of the pneumatic path that is located within the RPT device 4000.

The RPT device 4000 may comprise electrical components 4200 such as an electrical power supply 4210, one or more input devices 4220, a central controller 4230, a therapy device controller 4240, a pressure device 4140, one or more tion circuits 4250, memory 4260, transducers 4270 (for example one or more of a flow sensor 4274, a pressure sensor 4272 and a speed sensor 4276), data communication interface 4280 and one or more output s 4290 (for example a display 4294 and display driver 4292). Electrical components 4200 may be mounted on a single d Circuit Board Assembly (PCBA) 4202. In an alternative form, the RPT device 4000 may include more than one PCBA 4202.

The central controller 4230 of the RPT device 4000 may be programmed to execute one or more algorithm modules, such as a ocessing module, a therapy engine module, a pressure control module, and a fault condition module. 505809DIV4 .4.1 RPT device mechanical & pneumatic components 4100 .4.1.1 Air filter(s) 4110 An RPT device in accordance with one form of the present technology may e an air filter 4110, or a plurality of air filters 4110.

For example, the air filter 4110 may be located at the beginning of the pneumatic path upstream of a blower 4142 as an inlet air filter 4112, or at the outlet of the RPT device 4000 as an outlet air filter 4114. See Fig. 4b. .4.1.2 Muffler(s) 4120 In one form of the present logy, an inlet muffler 4122 is located in the pneumatic path, such as upstream of a pressure device 4140 or downstream of the pressure device 4140. See Fig. 4b. .4.1.3 Pressure device 4140 In a preferred form of the present technology, a pressure device 4140 for producing a flow of air at positive pressure is a controllable blower 4142. For example the blower may include a brushless DC motor 4144 with one or more ers housed in a . The blower may be preferably capable of delivering a supply of air, for example about 120 litres/minute, at a positive pressure in a range from about 4 cmH2O to about 20 cmH2O, or in other forms up to about 30 cmH2O.

The blower may include a blower as bed in any one of the following s or patent applications the contents of which are incorporated herein in their entirety: U.S. patent number 7,866,944; U.S. patent number 8,638,014; U.S. Patent number 8,636,479; and PCT patent application publication number .4.1.4 Anti-spill back valve 4160 In one form of the present technology, an anti-spill back valve is located between the humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is ucted and arranged to reduce the risk that water will flow upstream from the humidifier 5000, for example to the motor 4144. 505809DIV4 .4.1.5 Air circuit 4170 An air circuit 4170 in ance with an aspect of the present technology is constructed and arranged to allow a flow of air between the pneumatic block 4020 and the patient interface 3000. In some forms, the air circuit 4170 may comprise a heating t configured to heat the flow of air travelling through the air circuit 4170. .4.1.6 Oxygen ry 4180 In one form of the present technology, supplemental oxygen 4180 is red to one or more points in the pneumatic path, such as upstream of the pneumatic block 4020, to the air circuit 4170 or to the patient interface 3000. .4.2 RPT device electrical components 4200 .4.2.1 Power supply 4210 In one form of the present technology power supply 4210 is internal of the external g 4010 of the RPT device 4000. In another form of the present technology, power supply 4210 is external of the external housing 4010 of the RPT device 4000.

In one form of the present technology power supply 4210 provides electrical power to the RPT device 4000 only. In another form of the present technology, power supply 4210 provides ical power to both RPT device 4000 and humidifier 5000. .4.2.2 Input devices 4220 In one form of the present technology, an RPT device 4000 includes one or more input devices 4220 in the form of s, 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 ted to the external housing 4010, or may, in another form, be in wireless communication with a receiver that is in electrical connection to the central controller 4230. 505809DIV4 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. .4.2.3 Central controller 4230 In one form of the present technology, the central controller 4230 is a dedicated electronic circuit configured to receive input signal(s) from the input device 4220, and to provide output signal(s) to the output device 4290 and / or the y device controller 4240.

In one form, the l controller 4230 is an application-specific integrated circuit. The central controller 4230 may comprise discrete electronic ents.

In another form of the present technology, the central controller 4230 is a processor suitable to control an RPT device 4000 such as an x86 INTEL processor.

A processor suitable to control an RPT device 4000 in ance with another form of the present technology includes a processor based on ARM Cortex-M processor from ARM Holdings. For example, an STM32 series microcontroller from ST MICROELECTRONICS may be used.

Another sor suitable to control an RPT device 4000 in accordance with a further ative form of the present technology includes a member selected from the family ARM9-based 32-bit RISC CPUs. For example, an STR9 series microcontroller from ST MICROELECTRONICS may be used.

In certain alternative forms of the present technology, a 16-bit RISC CPU may be used as the processor for the RPT device 4000. For example a processor from the MSP430 family of microcontrollers, manufactured by TEXAS INSTRUMENTS, may be used.

The central controller 4230 is ured to receive input signal(s), such as input s from one or more transducers 4270, one or more humidifier transducers and one or more input devices 4220. 505809DIV4 The central controller 4230 is configured to provide output signal(s) such as to one or more of an output device 4290, a therapy device controller 4240, a data ication interface 4280 and humidifier controller 5550.

In some forms of the present technology, the central controller 4230, or multiple such central controllers, is ured to implement the one or more methodologies described herein such as the one or more algorithms expressed as computer programs stored in a non-transitory computer readable storage medium, such as memory 4260. In some cases, as previously sed, such sor(s) may be integrated with an RPT device 4000. However, in some forms of the present logy the processor(s) may be implemented discretely from the pressure generation components of the RPT device 4000, such as for purpose of performing any of the methodologies described herein t ly controlling delivery of a respiratory treatment. For example, such a processor may perform any of the methodologies described herein for es of determining control settings for an RPT device by analysis of stored data such as from any of the sensors described herein. .4.2.4 Clock 4232 Preferably RPT device 4000 includes a clock 4232 that is connected to a central controller 4230. .4.2.5 Therapy device controller 4240 In one form of the t technology, therapy device controller 4240 is a pressure control module that forms part of the algorithms executed by the central controller 4230.

In one form of the present technology, therapy device controller 4240 is a dedicated motor control integrated circuit. For example, in one form a MC33035 brushless DC motor controller, manufactured by ONSEMI is used. .4.2.6 Protection circuits 4250 Preferably an RPT device 4000 in accordance with the t technology comprises one or more tion circuits 4250. 505809DIV4 One form of protection circuit 4250 in accordance with the present technology is an electrical protection circuit.

One form of protection t 4250 in accordance with the present technology is a temperature and/or pressure safety circuit. 7 Memory 4260 In accordance with one form of the present technology the RPT device 4000 includes memory 4260, preferably non-volatile memory. In some forms, memory 4260 may include battery powered static RAM. In some forms, memory 4260 may include volatile RAM.

Preferably memory 4260 is located on PCBA 4202. Memory 4260 may be in the form of EEPROM, or NAND flash.

Additionally or alternatively, RPT device 4000 includes removable form of memory 4260, for example a memory card made in accordance with the Secure Digital (SD) standard.

In one form of the present technology, the memory 4260 acts as a nontransitory computer readable storage medium on which is stored computer m instructions expressing the one or more methodologies described herein, such as the one or more algorithms. 8 Transducers 4270 Transducers may be internal or external of the RPT device 4000. External transducers may be located for example on or form part of the air circuit 4170 humidifier 5000 and/or the patient interface 3000. External transducers 4270 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.

In one form of the present technology, one or more transducers 4270 may be constructed and arranged to e properties of the air, such as at one or more points in the tic path or of ambient air. In another form, one or more transducers 4270 may be ured to measure properties of the RPT device 4000 such as motor speed and/or motor current. 505809DIV4 .4.2.8.1 Flow 4274 A flow transducer 4274 in ance with the present technology may be based on a ential pressure transducer, for example, an SDP600 Series differential pressure transducer from SENSIRION. The ential pressure transducer is in fluid communication with the pneumatic circuit, with one of each of the pressure transducers connected to respective first and second points in a flow restricting element.

In use, a signal representing total flow Qt from the flow transducer 4274 is received by the central controller 4230. 8.2 Pressure 4272 A re transducer 4272 in accordance with the present technology is located in fluid communication with the pneumatic t. An example of a suitable pressure transducer is a sensor from the HONEYWELL ASDX series. An ative suitable pressure transducer is a sensor from the NPA Series from GENERAL ELECTRIC.

In use, a signal from the pressure transducer 4272 is received by the central controller 4230. In one form, the signal from the pressure transducer 4272 may be filtered prior to being received by the central controller 4230. .4.2.8.3 Motor speed 4276 In one form of the present technology a motor speed signal is generated. A motor speed signal is ably provided by therapy device controller 4240. Motor speed may, for example, be generated by a speed sensor, such as a Hall effect sensor. .4.2.9 Data communication interface 4280 In one preferred form of the present technology, a data communication interface 4280 is ed, and is connected to central controller 4230. Data communication interface 4280 is preferably connectable to remote external communication network 4282. Data communication ace 4280 is preferably connectable to local external communication network 4284. Preferably remote external communication network 4282 is connectable to remote external device 4286. 505809DIV4 Preferably local external communication network 4284 is connectable to local external device 4288.

In one form, data communication interface 4280 is part of central controller 4230. In another form, data ication interface 4280 is an integrated circuit that is separate from l ller 4230.

In one form, remote external communication network 4282 is the Internet.

The data communication interface 4280 may use wired communication (e.g. via Ethernet, or optical fibre) or a wireless protocol to connect to the et.

In one form, local external communication network 4284 utilises one or more communication standards, such as oth, or a consumer infrared ol.

In one form, remote external device 4286 is one or more computers, for example a cluster of networked computers. In one form, remote al device 4286 may be virtual computers, rather than physical computers. In either case, such remote external device 4286 may be accessible to an appropriately authorised person such as a clinician.

Preferably local external device 4288 is a personal computer, mobile phone, tablet or remote control.

Output devices including optional display, alarms 4290 An output device 4290 in accordance with the present technology may take the form of one or more of a visual, audio and haptic unit. A visual display may be a Liquid Crystal Display (LCD) or Light Emitting Diode (LED) display. .4.2.10.1 Display driver 4292 A display driver 4292 receives as an input the characters, symbols, or images intended for display on the display 4294, and converts them to commands that cause the display 4294 to y those ters, symbols, or images. .4.2.10.2 Display 4294 A display 4294 is configured to visually display characters, symbols, or images in response to commands received from the display driver 4292. For example, 505809DIV4 the display 4294 may be an eight-segment display, in which case the display driver 4292 converts each character or symbol, such as the figure "0", to eight logical signals indicating whether the eight respective segments are to be activated to display a particular character or symbol. .5 HUMIDIFIER 5000 .5.1 Humidifier ew In one form of the present technology as shown in Fig. 7, there is provided a fier 5000 for increasing a moisture content, or absolute humidity, of a flow of air in relation to the ambient air (air surrounding the t), before the flow of air is delivered to the entrance of the patient’s airways. In one example, the humidifier 5000 may deliver a flow of humidified air at 80 % relative humidity and 27 °C.

Characteristics of prior art humidifiers may include from one or more of: slow response time, long warm-up time, large volume and/or footprint and risk of water spillage. A humidifier 5000 according to the present technology seems to e upon, or ameliorate, one or more of the above characteristics.

The humidifier 5000 may se an air inlet 5002 to receive the flow of air, and an air outlet 5004 to r the flow of air with added humidity. .5.2 Humidifier components 1 Water reservoir 5110 According to one aspect of the present technology, the humidifier 5000 may comprise a water reservoir 5110 as shown in Fig. 8. The water reservoir 5110 may be configured to hold a ermined, maximum volume of water (or other suitable liquids), which may be used to increase absolute humidity of the flow of air.

In one form, the reservoir 5110 may be configured to hold several hundred millilitres of water, for use during at least the length of the patient’s sleep in a day. However, in other forms, other sizes such as a smaller reservoir for a le, travel-friendly system or a larger reservoir for a hospital system may be also suitable.

Yet further, a reservoir 5110 may be replaced by, or connected to, a water supply. 505809DIV4 According to some arrangements, the water reservoir 5110 may comprise, or be coupled to, a water volume detector 5112 by which the amount of water in the reservoir 5110 may be determined. The water volume detector 5112 may ine the volume of water based on one or more of a presence, weight, optical property, onic property or a head of the water of the reservoir 5110. Any of the mechanisms or methods such as those described in the Australian Provisional Patent Application AU 2013904049 may also be suitable for use with the present technology, the entire contents of which is incorporated herewithin by eference.

In some forms, the water reservoir 5110 may be configured to heat the water prior to the water entering the humidification chamber 5200, for e by comprising, or being coupled to, a reservoir heating element 5221 as shown in Fig. 8. .5.2.2 Water delivery mechanism 5150 According to one aspect of the present logy, the humidifier 5000 may comprise a water delivery mechanism 5150 configured to deliver a flow of water from the water oir 5110 to a humidification chamber 5200 (see Fig. 8). The water delivery mechanism 5150 may comprise a water pump 5152 and a water delivery conduit 5154, and may be in fluid communication with a water feed inlet 5206 to deliver the flow of water to the humidification chamber 5200. The water ry mechanism 5150 in some forms may further comprise a valve (e.g. water check valve 5158) for preventing delivery of water from the reservoir 5110 to the humidification chamber 5200.

Preferably, the humidification chamber 5200 comprises a water retention feature such as a humidifier wick 5230, which receives the flow of water from the water ry ism 5150. In some forms, the humidifier 5000 may comprise a plurality of water delivery mechanisms 5150 and/or a plurality of water feed inlets 5206 in order to better l a distribution of water in the humidifier wick 5230. In this disclosure, a water flow rate will be taken to mean a rate of flow of water from the water reservoir 5110 to a humidification chamber 5200 unless explicitly stated otherwise. 505809DIV4 The water flow rate(s) that the humidifier 5000 is configured to provide may vary according to factors such as the uration of the humidifier 5000 and a range of expected operating conditions such as ambient conditions (e.g. ambient temperature/humidity), humidifier operating ters (e.g. maximum heat output of the heating element 5220, maximum water capacity of the humidifier wick 5230) and/or therapy conditions (e.g. therapy pressure, air flow rate, patient comfort/preference). For example, a change in therapy pressure only may cause a change in the water flow rate, such as due to a se by the humidifier controller 5550, or due to a property of the water delivery ism 5150.

In one form, the range of water flow rates able to be provided by the humidifier 5000 may be between 0 ml/min and 2 ml/min, for example between 0 ml/min and 1 ml/min, or between 0 ml/min and 0 ml/min. In one form, the humidifier 5000 may be configured to provide one of a number of discrete water flow rates, for example 0.0 ml/min, 0.2 ml/min, 0.4 ml/min, 0.6 ml/min or 0.8 ml/min where the limits of water flow rates able to be provided are 0.0 ml/min and 0.8 ml/min. In other forms, the humidifier 5000 may be configured to provide any water flow rate between its limits by providing an analogue control of the flow rate. The water flow rate at a particular time during ion of the humidifier 5000 may then depend on the set of operating ions at the particular time. For example, a typical value with an air flow of 35 l/min and desired added humidity of 15 mg/l requires a water flow of 0.5 ml/min.

A pressure of the flow of air (also known as air pressure) in a respiratory device and its pneumatic path downstream f may vary during y, for example between 4 and 30 cmH2O. Thus, preferably, the water pump 5152 is configured to deliver a consistent water flow rate across various air pressures in the humidifier 5000. Preferably (however not necessarily), the water flow rate provided by the water pump 5152 may be independent from (i.e. not be affected by) the air pressure in the humidifier 5000. Such a water pump 5152 would be advantageous in that the air pressure may be varied independently of the amount of humidification provided thereto for ed controllability of the therapy system.

In one form, the water pump 5152 may be a positive displacement type pump, such as one described in Australian ional Patent Application Number 505809DIV4 AU 2013903277, the entire contents of which is incorporated thin by crossreference.

In another form, many other types of pumps such as metered pumps, peristaltic pumps, gravity-fed pumps, or pumps utilising blower pressure may be suitable to be used in the water ry mechanism 5150. An elevated water reservoir (not shown) such as a drip bag may also be suitable and act as a pump of sorts to deliver water.

In some forms, where a water flow rate through the water pump 5152 may be affected by the air pressure, the flow rate h the water pump 5152 may be sated accordingly. For instance as shown in Fig. 8, the water delivery mechanism 5150 may additionally comprise one or more of a metering mechanism 5156, a water check valve 5158 to measure and/or l the water flow rate through the water pump 5152. Alternatively, the humidifier controller 5550 may be used to compensate for the effects of any changes to the air pressure, by controlling the water pump 5152 according to the air pressure which may be received by the humidifier controller 5550 as an input. In some forms, the humidifier controller 5550 may be used to compensate for the s of any changes to the air flow rate (e.g. due to a change in leak), by controlling the water flow rate through the water ry mechanism 5150.

In another ement (not shown), a water pump 5152 may be configured to pump water by utilising a pressure such as that ted by the RPT device 4000. The pressure may then be used to draw water from the water reservoir 5110 into the humidification chamber 5200. The water flow rate in such an ement may be a function of the air flow rate, and thus the humidifier 5000 in this arrangement may further comprise a control valve to regulate the water flow rate.

The humidifier 5000 may in some forms comprise a fault detection mechanism to detect conditions such as blockages in the water delivery mechanism 5150 or a shortage of water in the reservoir 5110, as will be described in further detail below. For example, a blockage in a positive displacement pump may cause its motor to stall, causing the pump to stop. Furthermore, the humidifier 5000 may be configured to detect accumulation of precipitates and/or contamination, such as in the wick 5230, as precipitants or contaminants may adversely affect performance of the humidifier 5000. .5.2.3 Humidification chamber 5200 According to one aspect, the humidifier 5000 may comprise a humidification chamber 5200, in which moisture is added to the flow of air, thus increasing the absolute humidity, prior to being delivered to the patient 1000. In one form, a cross-section of which is shown in Fig. 9a, the humidification chamber 5200 may comprise a humidifier wick 5230, a water feed inlet 5206 and a g t 5220.

Preferably, the humidification chamber 5200 is in fluid communication with, and receives water from, the water reservoir 5110 through the water feed inlet 5206. The water feed inlet 5206 may comprise an inner diameter of between about 0.5 mm to 3 mm in some forms, such as 1 mm, 1.5 mm, 2 mm or 2.5 mm. Preferably, the water feed inlet 5206 is iently large to reduce a risk of obstruction of the water feed inlet 5206, for example due to a build-up of contaminants.

In one form, the humidification chamber 5200 may comprise an outer housing 5202 ured to provide thermal tion to the outside, as well as to protect an interior of the humidification chamber 5200 such as any components therein. The outer housing 5202 may comprise a plurality of portions such as an inlet portion 5202a, heater cover n 5202b and outlet portion 5202c that are coupled together. The inlet portion 5202a may se the air inlet 5002 and the outlet portion 5202c may comprise the air outlet 5004 as shown in Fig. 9a. The water feed inlet 5206 is shown located in the inlet portion 5202a, but may be located in any one of the portions 5202a, 5202b, 5202c. If multiple water feed inlets 5206 are present, the additional water feed inlets 5206 be located in one or more of the portions 5202a, 5202b, 5202c of the outer housing 5202. The heater cover portion 5202b may be configured to locate and retain the heating element 5220. In some arrangements the heating element 5220 may be retained between an inner housing 5204 and the heater cover portion 5202b of the outer housing 5202 as shown in Fig. 9a. The inner housing 5204 is configured to isolate the heating element 5220 from exposure to re, yet allow heat er to occur from the heating element 5220 to the humidifier wick 5230.

Fig. 9b shows a humidifier 5000 in another form according to the present technology. In this form, the heater cover portion 5202b of the outer housing 5202 is set away from the heating element 5220 so as to provide an air gap, for example for thermal insulation. The heater cover portion 5202b may also encloses the water feed inlet 5206 for protection as shown in Fig. 9b.

Suitable materials for the inner housing 5204 may include thermally tive materials, such as aluminium or its alloys, or thermally conductive polymeric/thermoplastic als such as Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS). Suitable materials for the outer housing 5202 may include polymeric materials such as PC/ABS, and the outer housing 5202 may include elastomeric portions such as thermoplastic elastomer (TPE). The outer housing 5202 may comprise a diameter of between about 10mm and 50mm, and be about 1-3 mm thick. The thickness of the inner housing 5204 may be about 1-3 mm, and may vary according to the material used, for example in order to achieve ient heat conductivity. It is to be understood that such dimensions and arrangements are exemplary and are not intended to be limiting. It is to be understood that the inner housing 5204 and/or the outer housing 5202 may have a different shape to those shown and/or be formed of a different number of portions, such as one, two, four, five or more portions.

According to one aspect, the water feed inlet 5206 may be in fluid communication with the water delivery mechanism 5150 to r water to the fier wick 5230 as shown in Fig. 8. In some cases, the humidifier 5000 may comprise a water filter 5214 configured to reduce ingress of foreign matter into the humidification chamber 5200 and/or the wick 5230 through the flow of water. The water filter 5214 may be located at or near an outlet of the humidifier reservoir 5110 (as shown in Fig. 8). The water filter 5214, or parts thereof, may be configured to be replaceable or ble. In some forms, the water filter 5214 may comprise a deioniser (not shown) where quality of the water in the reservoir 5110 is low.

In some arrangements (not shown), the water feed inlet 5206 may be located closer to the air outlet 5004 than the air inlet 5002. Such an arrangement may encourage at least some portion of the flow of water in the wick 5230 to travel in an opposing ion to the direction of the air flow in the fication chamber 5200.

Thus, the temperature and humidification gradient within the water in the wick 5230, as well as within the air flow may be optimised to se the differential temperature and humidification therebetween in order to improve humidification performance.

According to another aspect, the humidification chamber 5200 may further comprise an air flow baffle 5208 (as shown in Fig. 9a and Fig. 10) configured to promote local turbulence and/or increase the evaporative surface area, such as by extending a length and/or a residence time during which the flow of air is in the humidification chamber 5200, for example to e humidification performance. In one form, the air flow baffle 5208 may force the flow of air to travel in a us path, such as a helical path as shown in Fig. 10. Inclusion of the air flow baffle 5208 in a humidification r 5200 may help reduce a size, such as a , of the humidification chamber 5200, in comparison to a length of the path for the air flow in the humidification chamber 5200 used without such an air flow baffle 5208.

Alternatively, or additionally, the humidification chamber 5200 may further comprise one or more jump or trip ts (not shown) along an evaporation surface configured to improve humidification performance.

In some forms of the present technology the air flow baffle 5208 may comprise a membrane. The air flow baffle 5208 may also further comprise acoustic elements for noise reduction, such as a tuned chamber (or resonator) configurations, or a number of narrow flow paths configured to encourage pment of laminar flow and reduce noise. In one form, the flow paths formed by the air flow baffle 5208 may be ured to provide a high inertance to assist in reducing radiated noise. In some arrangements, the air flow baffle 5208 may comprise variable damping properties for reducing noise and/or vibrations.

In some arrangements, the humidification chamber 5200 may comprise a bypass port for sensing one or more properties of the flow of air as it passes through the humidification chamber 5200.

Additionally, or alternatively, the humidification chamber 5200 may be configured to only add humidity to the flow of air for an inhalation phase of a patient’s breath. In one form, the humidifier 5000 may comprise a bypass path which may be used divert the air flow away from the humidification chamber 5200 for at least a part of a breath cycle, for e using a valve. This may allow for delivery 505809DIV4 of an air flow to the patient interface 3000 without humidification during some parts of a breath cycle, such as during exhalation. .5.2.3.1 Heating element 5220 The amount of re, or absolute humidity, that a flow of air is able to retain in vapour form varies according to a temperature of the flow of air.

In some cases, the flow of air received by the humidifier 5000 may be too cold to retain adequate absolute humidity for delivery to the entrance to the airways of the patient 1000. Furthermore, ry of cold air may cause fort to the patient 1000 as described above. Thus, a humidifier 5000 may comprise a heating element 5220 configured to output heat, for example to heat the flow of air. In one form, the g element 5220 may be located in the humidification chamber 5200, such as between the inner housing 5204 and the outer housing 5202 as shown in Fig. 9a. atively, or additionally, the humidifier reservoir 5110 may comprise a reservoir heating element 5221 to heat water prior to it ng the humidification chamber 5200 as shown in Fig. 8.

The g element 5220 may heat the flow of air as it passes through the humidifier 5000, as well as to assist humidification in the humidification chamber 5200 such as by heating the humidifier wick 5230. Accordingly, the heating element 5220 may be configured so that it provides sufficient thermal energy for heating and vaporisation at the highest requirements respectively, that is, where the t air is cold and dry.

The g element 5220 may be ured in one of a number of ways whilst meeting the above requirements. In one form, a heating element 5220 may comprise an approximately 10 cm2 surface area that generates a maximum thermal output of 40 Watts. In another form, a heating element 5220 may comprise an approximately 40 cm2 surface area with the same maximum thermal output value of 40 Watts. It should be understood that the maximum thermal output value need not be limited to 40 Watts. Examples of onships between a power output of a humidifier 5000 are shown in Fig. 17 and Fig. 19, and an example of a relationship between added humidity and temperature of the heating element is shown in Fig. 18. 505809DIV4 According to one aspect of the present logy, the heating element 5220 may be zoned. That is, the heating t 5220 may comprise multiple ns, or zones, that may be controlled tely and/or have variable properties.

In some cases, variable properties of the zones may e shape, heat output, insulation, proximity to the wick 5230 or proximity to water feed inlet 5206. Yet further, each zone may be controlled independently of each other by the humidifier controller 5550, and in some cases controlled relatively to each other. An example of a heating element 5220 which may allow relative control of the zones is shown in Fig. 11. In this example, the heating element 5220 may comprise four zones 5220_1, 5220_2, 5220_3 and 5220_4, wherein the heating output of each zones may be configured to be 10%, 20%, 30% and 40% of a total heat output of the heating element 5220. There may be a different number of heating zones, such as two, three, five or more zones and properties of the zones such as their shape, size or maximum heat output may vary.

One suitable form of a heating element 5220 may comprise a resistive electrical track on a circuit board. The t board may comprise a substrate which could be used as a thermally conductive, electrically resistive barrier between the resistive electrical track and the wick 5230. In one form, the heating element 5220 may comprise a flexible circuit board. In another form, the heating t 5220 may comprise a metallic lly conductive substrate, which is separated by a tric laminate layer from the heating track. ative forms of a heating element 5220 may be also suitable such as an inductive heater, if the heating element 5220 is configured to be able to provide a heat output to the wick 5230 and/or the humidification chamber 5200.

In another form, the resistive electrical track of the heating element 5220 may comprise a resistive wire. The resistive wire may wrap around an outer housing 5202 as shown in Fig. 20, for example by forming a plurality of loops around the surface. In one example, each stand of wire may be bonded to adjacent s) of wire, such as by an adhesive (e.g. epoxy). In another example, each strand of wire may se an insulating layer, which may be further configured to bond to adjacent strand(s) of wire when heat is applied thereto. Thus the plurality of loops of the resistive wire may be formed around the outer housing 5202, and heat may be 505809DIV4 applied to the heating element 5220 (e.g. externally, or by applying a current through the heating element 5220) to bond the strands together.

As described above, the heating element 5220 may take one of a number of possible forms in shape and/or construction. Thus, it should be understood that gh the heating element 5220 is shown (e.g. in Fig. 9a and Fig. 11) to be a cylindrical shape, it need not be limited to such a shape. For example, the heating element 5220 may be constructed as a flat, rectangular sheet, as an extruded arc shape, as a rectangular prism, or a plurality of parallel sheets, among others.

The heating element 5220 may be disposable in some cases. For ce, the entire humidification chamber 5200 may be disposable wherein the g element 5220 is formed integrally within the humidification chamber 5200 as a part of a disposable component. Alternatively, the heating element 5220 may be configured to be disposable and easily ed by removal from the humidification chamber 5200, for example by inserting, such as g, into the humidification chamber 5200 for installation. .5.2.3.2 Humidifier wick 5230 In one aspect of the present technology, the humidifier 5000 may comprise a humidifier wick 5230. The humidifier wick 5230 may be configured to retain a volume of water, which may be ed from the reservoir 5110 for evaporation to humidify the flow of air before it is delivered to the t 1000.

A maximum volume of water able to be retained by the humidifier wick 5230, or a water capacity of the humidifier wick 5230, may be predetermined. In one aspect, the water capacity of the humidifier wick 5230 is preferably small enough to ensure a short response time of the humidifier 5000. According to another aspect, the water capacity of the humidifier wick 5230 is sufficiently large to allow adequate humidification at the highest flow rates and driest ambient conditions, by ensuring an adequately large surface area of water. The water capacity of the fier wick 5230 may be approximately 10 g, r other values may also be appropriate such as approximately 2 g, 6 g, 15 g, 20 g, 30 g, or any other values therebetween. In other forms, a larger or a smaller water capacity of the humidifier wick 5230 may be suitable. 505809DIV4 A condition n the water capacity of the humidifier wick 5230 is met by the water content in the humidifier wick 5230 may be referred to as ‘saturation’ or ‘flooding’ of the wick 5230. In some cases, it may be preferable to e the humidifier 5000 such that the humidifier wick 5230 is not saturated during use.

Disadvantages caused by saturation of the humidifier wick 5230 may include introduction of water droplets in the humidifier 5000 and/or the air circuit 4170 due to spitting. Detection of saturation of the humidifier wick 5230 may be thus desirable, which will be described in further detail below. In some cases, the air circuit 4170 may comprise a portion of the wick 5230, or a ary wick (or water trap), to ameliorate any potential problems related to spitting, such as by absorbing any spitting or rainout.

According to one , the wick 5230 may be constructed with nonhomogenous geometry and/or construction. Thus, one or more properties of the wick 5230 such as the water ty, surface area exposed to air, or heat conductivity may be varied for each area of the wick 5230. For instance, the wick 5230 may be nonhomogenous along the direction of air flow, or along a ce from the water feed inlet 5206, for e so that the wick 5230 becomes thinner the further away from the water feed inlet 5206. In one form, geometry of the wick 5230 may vary in one or more of the depth, number of layers, the density and/or material of the wick 5230.

For example, the humidifier wick 5230 may comprise one or more layers, such as a first layer 5230a and a second layer 5230b as shown in Fig. 12. The one or more layers may vary in form and/or functions. In one ce, the first layer 5230a may be a transport layer in communication with the water feed inlet 5206, and the second layer 5230b may be an evaporation layer laid over the first layer 5230a and in contact with the flow of air. In this construction, the first layer 5230a may be configured to optimise storage of water per volume and/or fast transport of water, and the second layer 5230b may be configured for improved evaporation characteristics, for example by increasing an exposed e area per volume. In some forms, the humidifier wick 5230 may be configured so that one or more layers may be replaced independently of each other, wherein the one or more layers may or may not be identical in form and/or function. 505809DIV4 In some forms, the humidifier wick 5230 may comprise a surface configured to increase a total surface area exposed to the flow of air. This may increase the area over which the water retained by the humidifier wick 5230 is in contact with the air flow, in order to improve humidification efficiency. For instance, the fier wick 5230 may comprise a corrugated inner surface as shown in Fig.

A humidifier wick 5230 according to the t technology may comprise a single continuous component, multiple components working as an assembly, or a discontinuous, discrete collection of wicking als and/or elements. In the present document all or any of the above variations will be referred to as a ‘humidifier wick’ 5230. A person skilled in the art would understand that the humidifier wick 5230 need not be constructed as a single piece of g material.

According to another aspect, the humidifier wick 5230 may be heated, for e by the heating element 5220. One advantage of a heated wick 5230 may be that a rate of evaporation may be lled. In one form, the fier wick 5230 may be thermally coupled to the heating element 5220, for example by contact as shown in Fig. 12.

A performance of the humidifier wick 5230 may degrade over time and/or usage, and in some cases the humidifier wick 5230 may no longer be suitable for use.

For ce, foreign matter, such as particulates from the water, may collect or build up on the humidifier wick 5230 as it is evaporated. In some cases, collection of foreign matter may reduce water capacity and/or heat conductivity of the humidifier wick 5230. In some cases, the fier wick 5230 may deteriorate over time, possibly even without any use of the humidifier 5000. Still r, the foreign matter collected on the humidifier wick 5230 may be removed from the humidifier wick 5230 and be entrained onto the flow of air, which may be undesirable.

Thus, in one aspect of the present technology, the fier wick 5230 may be cleaned and/or replaced. Furthermore a condition of the humidifier wick 5230 may be determined, such as its water capacity and/or its remaining usable life, and provide an indication or message when the humidifier wick 5230 needs replacing or to an expected time to replacement. 505809DIV4 According to another aspect, a pattern of distribution of foreign matter on the humidifier wick 5230 may be ined and/or controlled. For ce, the humidification chamber 5200 may be configured to encourage collection of foreign matter on the humidifier wick 5230 according to a predetermined pattern. Still further, the ermined pattern of n matter build-up on the fier wick 5230 may be used as an indicator of a remaining life of the humidifier wick 5230. For example, the fier wick 5230 may be configured so that foreign matter may begin to collect from one predetermined region of the humidifier wick 5230, and for the collection to grow in a predetermined direction. Then, detection of a build-up of foreign matter, for example in a predetermined life-indicator region may be used to indicate that the fier wick 5230 may be no longer suitable for use.

A cross-section of the humidifier 5000 (wick frame 5232 not shown) showing an arrangement of a humidifier wick 5230 in use is shown in Fig. 14. In this example, the humidifier wick 5230 holds a volume of water, however the volume of water may be less than the water capacity of the humidifier wick 5230. Accordingly the humidifier wick 5230 may be shown to comprise of two regions, a wet region 5230_W and a dry region 5230_D, separated by a water boundary, is shown as 5230_WB. Typically, formation or collection of any foreign matter from water onto the humidifier wick 5230 may predominantly occur at the boundary edge, as this is the point at which particulates are dried. Accordingly, one of the aspects of the present logy relates to a control of the water boundary 5230_WB, through construction of the wick 5230 and/or foreign matter management algorithms, as described further below.

In one form, the wick 5230 may be configured to allow washing, e.g. in a dishwasher, ection using another agent, and/or using a microwave. Additionally, or alternatively, the humidifier wick 5230 may comprise an antimicrobial or antibacterial agent such as silver. Yet further, the humidifier 5000 may comprise selfcleaning algorithms (such as a bio-burden reduction algorithm) as will be described further below. ing to one aspect, the fier wick 5230 may further comprise added matter such as a drug to be introduced to the flow of air, or a life indicator. The life indicator may comprise a coloured portion which changes colour to indicate to the 505809DIV4 user or the patient 1000 that the humidifier wick 5230 should be ed. The humidifier wick 5230 may comprise a drug which may be released by vaporisation to the flow of air to be delivered to the patient 1000.

The humidifier wick 5230 may comprise, or be combined with, the heating element 5220 in some cases. For instance, the wick 5230 may comprise a printed carbon portion which may form ive tracks for heating, and a paper-based portion for water retention and evaporation which also acts as the substrate for the printed carbon n. In one form, the heating element 5220 may be coupled (e.g. printed) onto one or both sides of the wick 5230 so as to create an integrated component. The ated component may further comprise one or more connectors which may be coupled (e.g. printed) onto one or both sides of the wick 5230, for example for connection to the controller 5550.

The humidifier wick 5230 may comprise one or more humidifier transducers. The fier transducers and humidifier algorithms which may receive inputs from the humidifier transducers are described in further detail below.

In another , the humidifier wick 5230 may be configured in a shape to facilitate easy insertion and/or removal with respect to the humidification chamber 5200. In one form, a portion of the fier wick 5230 such as a tab (not shown) may be configured to be accessible for removal while the humidifier wick 5230 is in its operating position. Yet further, the humidifier 5000 may be configured as shown in Fig. 14 such that a component (such as an outer housing component 5202_c) may be removed to allow access to the humidifier wick 5230. Additionally, or alternatively, the fier wick 5230 may be configured in a frustro-conical shape complementarily to a similarly shaped fication chamber 5200, so that it would self-locate during insertion into its operating on. 3.3 Wick frame 5232 According to one aspect, the humidifier 5000 may comprise a wick frame 5232 shown in Fig. 9a and Fig. 10. The wick frame 5232 may be coupled to the wick 5230, for instance to locate and/or shape the wick 5230, maintain the wick 5230 in close proximity to the heating element 5220, and/or to prevent an increase in flow impedance which may occur due to a deformation of the wick 5230. The wick frame 505809DIV4 5232 may promote, or maintain, thermal contact between the wick 5230 and the heating element 5220 by assisting in locating and/or shaping the wick 5230 as designed. In a form shown in Fig. 10, the wick frame 5232 may comprise a wick locator 5233 such as a shoulder as shown, to assist in location of the wick 5230 in relation to the wick frame 5232 in assembly.

The wick frame 5232 may be further configured to assist in removal and/or insertion of the wick 5230 with respect to the humidifier 5000, for instance by ing a grip surface 5232_G to assist a user and/or the t 1000 to locate and/or hold the wick frame 5232. The grip surface 5232_G may be marked (e.g. using colours and/or indicators) for identification, and/or textured to assist the users to hold onto the grip 5232_G. In some forms, where the humidifier wick 5230 is disposable, the wick frame 5232 may be configured to be disposed with the humidifier wick 5230, for example by being integrally formed. In other cases, the wick frame 5232 may be configured to accept and hold the humidifier wick 5230, for e so that the wick 5230 may be replaced while the wick frame 5232 is removed from the humidifier 5000. Then the wick frame 5232 may accept a new wick 5230 and be inserted into the humidifier 5000. In some forms, the wick frame 5232, the wick 5230 and the heating element 5220 may be coupled together and configured to be able as a unit.

According to r aspect, the wick frame 5232 may be configured to be d by a 3-D r, for example by the patient 1000, or a caregiver, such as in a hospital or in a home environment. Alternatively, or onally, the wick frame 5232 may be moulded as one component, or an assembly of a plurality of moulded components. In some forms, the wick 5230 and the wick frame 5232 may be a single component.

In one form, the wick frame 5232 may further comprise an air filter upstream and/or downstream of the wick 5230. The air filter may be placed upstream of the wick 5230 in order to reduce introduction and/or collection of foreign matter onto the wick 5230. Alternatively, or additionally, the air filter may be placed downstream of the wick 5230 in order to reduce incidence of any foreign matter travelling from the wick 5230 to the patient 1000. 505809DIV4 According to another aspect, the wick frame 5232 may comprise the air flow baffle 5208 described above. Where the wick frame 5232 is combined with the air flow baffle 5208, the wick 5230 may form one surface of the path of the flow of air. This configuration may be advantageous in that the length of contact is increased between the flow of air and the wick 5230, which may improve humidification. .5.2.3.4 Humidifier filter 5240 One or more humidifier filters 5240 may be used in some arrangements of the fier 5000. The humidifier filter 5240 may be used to reduce the amount of undesirable components from the flow of air, for example by preventing the particulates that may have originated from evaporated water from being introduced into the flow of air. A humidifier filter 5240 may be placed anywhere in the humidifier 5000, such as at or near the inlet 5002 (as shown in Fig. 14), the outlet 5004 (as shown in Fig. 16), or etween (not shown). A filter (not shown) located downstream of the humidifier 5000, for example in the air circuit 4170, may substantially perform a similar on as a humidifier filter 5240 by ng the amount of undesirable component from the flow of air. .5.2.4 Humidifier transducers According to one aspect of the present technology, the humidifier 5000 may comprise one or more humidifier transducers configured to generate a signal indicative of the sensed characteristic, such as air flow rate, pressure, temperature or ty. Thus the humidifier 5000 may comprise one or more flow sensors 5512 (as shown in Fig. 15), one or more ature sensors (e.g. 5514_1, 5514_2, 5514_3, 5514_4 as shown in Fig. 15), and/or one or more ty sensors 5516 (as shown in Fig. 16) as well as any number of other types of sensors.

Some humidifier transducers may be located in the humidifier 5000 (e.g. g element temperature transducer E shown in Fig. 16), however humidifier ucers may also be located outside of the humidifier 5000 in some cases, for example in the air circuit 4170, or in the patient interface 3000.

Suitable locations for each of the one or more humidifier transducers may vary according to their purpose and/or algorithms which may use as inputs signals generated by each of the one or more humidity sensors 5516. In some cases, 505809DIV4 transducers configured to generate a signal indicative of a sensed teristic in one of the pneumatic path, such as the RPT device 4000, may be used to determine the sensed characteristics in another part of the pneumatic path, such as the humidifier 5000. .5.2.5 Humidifier ller 5550 In one form, the humidifier 5000 may comprise a humidifier controller 5550, which may be a standalone controller or a part of the central controller 4230 (as shown in Fig. 4c). The humidifier controller 5550 may monitor and/or control one or more operating parameters of the humidifier 5000 based on inputs from components such as other components of the humidifier 5000 and/or the RPT device 4000.

For instance, humidifier 5000 may receive inputs from such ents as humidifier transducers, input devices 4220 or memory 4260. Furthermore, the humidifier 5000 may output signals to the heating element 5220 or the water delivery ism 5150. .5.3 Humidifier algorithms 5600 Various humidifier algorithms 5600 (e.g. shown in Fig. 21) are described below. Although they are referred to ‘humidifier algorithms’, it is to be understood that these algorithms need not be stored in and/or executed by the humidifier 5000.

The term ‘humidifier algorithms’ is used herein to indicate that the algorithms relate to the humidifier 5000. For example, the humidifier algorithms 5600 may be ed by the central controller 4230 and stored in memory 4260 of the RPT device 4000. In some instances, the algorithms 5600 may be stored and/or executed from an external computer such as a hone in communication with the humidifier 5000. 1 Humidifier condition determination / fault mitigation algorithms According to one aspect, the humidifier 5000 may comprise algorithms configured to determine, or detect, one or more conditions of the humidifier 5000 and/or its components. In some cases, the humidifier 5000 may further se fault mitigation algorithms configured to ameliorate, or te one or more ed fault conditions. 505809DIV4 The humidifier condition determination algorithms may detect or ine ions of humidifier components such as the water reservoir 5110, water delivery mechanism 5150, humidifier wick 5230, heating element 5220 or humidifier transducers. The conditions detected or ined may include: water volume, such as in the water reservoir 5110, water flow rate, such as from the water delivery mechanism 5150, or water capacity and/or water content of the humidifier wick 5230. .5.3.1.1 Wick condition determination algorithms 5610 As described above, a performance and/or suitability for use of the humidifier wick 5230 may change over time and/or usage, for example due to buildup of foreign matter on the wick 5230 or degradation of the humidifier wick 5230.

Accordingly, the water ty of the humidifier wick 5230 may change, which may affect the amount of humidification which can be provided to the flow of air.

According to another aspect of the present logy, the humidifier 5000 may comprise one or more wick condition determination algorithms 5610 for determining one or more conditions of the humidifier wick 5230. The one or more conditions of the fier wick 5230 to be determined may include suitability of the wick for use, water capacity, water content, or remaining usable life of the humidifier wick 5230.

In some forms (e.g. a wick condition determination algorithm 5610A as shown in Fig. 22), a wick condition determination algorithm may receive one or more inputs from step 5610A2 to ine one or more conditions of the humidifier wick 5230 in step 5610A4. The one or more conditions of the humidifier wick may be determined by comparing the inputs to thresholds such as in step 5610A3. The one or more inputs may include wick characteristic, wick type, wick model, date of manufacture, water capacity, water content, date of last ement, time of usage, quantity of water evaporated using the wick 5230, number of times that the wick 5230 has been washed, or any others which may indicate a condition and/or a property of the wick 5230. Yet further, the wick condition determination algorithms may e inputs in some cases relating to ambient conditions. A wick condition determination algorithm may then determine one or more conditions of the wick 5230 based on one or more of the above inputs. Some of the wick ions determined may be used as 505809DIV4 further inputs to other wick conditions. For e, conditions such as water ty and/or the water content of the wick may be used as inputs to determine other wick conditions such as a remaining usable life of the wick 5230 or to determine whether the wick may be le for use, as shown in step 5610A5 of Fig. 22. If the wick 5230 is determined to be no longer suitable for use, the wick condition determination algorithm 5610 may generate a corresponding signal (e.g. in step 5610A6), for example to the humidifier controller 5550 so that the humidifier 5000 may communicate to the user of a need to change the wick 5230.

In some cases, a calibration algorithm may be able to indicate when a wick 5230 has been ed or washed, for example based on to an increase in its water capacity.

A wick condition determination algorithm 5610 may determine a water capacity of the wick 5230 in absolute terms or relative terms, for example as shown in an example algorithm 5610B shown in Fig. 23. That is, the water capacity of the wick 5230 may be determined as an absolute quantity of water that the wick 5230 is able to hold (as shown in step 5160B3 of Fig. 23) or as a relative ty (as shown in optional step 5160B5 of Fig. 23) such as in relation to a predetermined water capacity of the wick 5230 (as shown in input step 5160B4 of Fig. 23), or in relation to a minimum water capacity of the wick 5230 (not shown). The water capacity of the wick 5230 may be assessed prior to use (such as in step ) to determine that the wick 5230 is suitable for use. In some forms, the wick condition determination algorithm 5610 may r determine whether the wick 5230 is suitable for use (step 5610B6) and/or indicate the unsuitability of the wick (step 5610B7) based on the determined water capacity of the wick 5230.

In one form, a wick condition ination algorithm 5610 may determine a water content of the humidifier wick 5230 as a proportion of its water capacity. The wick condition determination algorithm 5610 may in some forms indicate when a wick saturation condition is reached, which is to say that the full water capacity of the wick 5230 has been met and/or exceeded. In some cases, determination of wick saturation may be used as an input to another humidifier thm, for example to stop, or slow down, operation of the water delivery mechanism 5150. 505809DIV4 In another aspect, the wick condition determination algorithm may determine a remaining life of the wick 5230 based on the current water capacity of the wick 5230 and the rate of change of the water capacity of the wick 5230 according to one or more previously measured water capacity values of the wick 5230.

In one form (e.g. shown in Fig. 24), a wick condition determination algorithm 5610 may ine a condition of the fier wick 5230 based on one or more temperatures at or near the humidifier wick 5230 (in step 5610C2), for example determined by sensing or measuring. In some cases, the one or more temperatures may be compared with nce values (in step 5610C3), which may be expected temperatures, atures measured from nearby sensors, or previously measured temperatures, to determine the condition of the humidifier wick 5230 (in step 5610C4). The expected atures may be based on one or more of operating ters of the humidifier 5000, such as a heat output from the heating element 5220, a flow rate of air through the humidifier 5000, and a water flow rate through the water feed inlet 5206, as well as any number of others. In some forms, the expected temperatures may be determined from one or more look-up tables or equations based on the one or more operating ters.

According to another aspect, the one or more temperatures may be measured and/or analysed relative to each other, for instance based on any al or spatial patterns. In one form, measures of temperature in a humidifier 5000 at various temperature sensors such as 5514_1, 5514_2, 5514_3, 5514_4 (see Fig. 15) may be measured and compared to each other. In another form, measured of temperature in a fier 5000 at a temperature sensor such as 5514_1 may be compared against another measure at the same temperature sensor 5514_1 which was taken at another time. For instance, an analysis may compare rates of change of the one or more temperatures against reference values. Alternatively, or additionally, a spatial distribution of temperatures, for example of the one or more temperatures ve to each other, may be compared against reference values.

In one form, one or more of the ing conditions of the humidifier 5000 may be varied while monitoring a response of one or more temperatures to determine a condition of the humidifier 5000. Examples of operating conditions to be varied may include a heat output from the heating element 5220, an air flow rate 505809DIV4 through the humidifier 5000, and a water flow rate through the water feed inlet 5206 as described above. However, the operating ions may include any number of other parameters.

One arrangement of the humidifier 5000 comprising temperature sensors , 5514_2, 5514_3 and 5514_4 is shown in Fig. 15. In this arrangement, measured temperatures and reference values may be obtained at one or more of the temperature sensors , 5514_2, 5514_3 and 5514_4 to determine a condition of the humidifier wick 5230.

In one example, measured temperatures at temperature sensors 5514_1, 5514_2, 5514_3 and 5514_4 may be 40°C, 41°C, 40°C and 52°C respectively, while the expected temperatures may be 40°C, 40.5°C, 41°C and , at a water flow rate of 1g/min. In this case, a wick condition determination algorithm 5610 may determine that the water flow rate is sufficiently high so that the wick 5230 should be wet around the temperature sensor , and thus determine the fier wick 5230 to have a reduced water capacity around the temperature sensor 5514_4.

In another arrangement of the humidifier shown in Fig. 16, a temperature sensor 5514_5 may be placed at a periphery of the humidifier wick 5230 furthest from the water feed inlet 5206 to indicate wick saturation. A wick condition determination algorithm (e.g. e algorithm 5610C) may be configured to monitor the ature at the sensor 5514_5, to determine a flooded condition (in step 5610C5).

Thus for example, if a temperature measured at the sensor 5514_5 is at or below a predetermined threshold, such as 2°C-5°C or more below a temperature of the heating element 5220, the wick 5230 may be deemed to be flooded, or saturated, by the wick condition determination algorithm 5610. In one form, the wick condition ination thm 5610 may determine a water capacity of the wick 5230 by ing a time for the wick 5230 to be saturated. Other sensors which may be suitable for use to indicate wick saturation may include an ultrasonic sensor, a noise sensor, a rain sensor and/or an image processing sensor. In some instances, where the wick is determined to be d, the water delivery mechanism 5150 may be stopped (in step 5610C6), and otherwise the water delivery mechanism 5150 may be continued to operate (in step 5610C7). 505809DIV4 In another form, the wick condition determination algorithm may determine a remaining life of the wick 5230 based on one or more mechanical properties of a wick 5230. The one or more mechanical properties may e noise/vibration characteristics such as a muffling or an acoustic profile. In other forms, a magnetic and/or optical characteristic of the wick 5230 may be used to determine a remaining life of the wick 5230.

In some forms, a wick condition determination algorithm 5610 may produce one or more outputs to be used by another humidifier algorithm. For instance, the wick condition determination algorithm 5610 may output water capacities of various zones of the wick 5230. Where a humidifier wick 5230 is determined to have a reduced water capacity in one zone, and the heating t 5220 comprises a plurality of heating zones, a heat output by the heating element 5220 to the corresponding g zones may be varied ing to the condition of the humidifier wick. .5.3.1.2 Plausibility check algorithms 5620 ing to another aspect, the humidifier may comprise one or more plausibility check algorithms 5620 configured to test for errors in operation of the humidifier 5000. The plausibility check algorithms 5620 may also check for performance of one or more individual ents of the humidifier 5000.

An example plausibility check algorithm 5620A (shown in Fig. 25) may receive as inputs inlet and/or ambient ions (step 5620A2), such as es of a temperature at the air inlet 5002, humidity at the air inlet 5002, ambient temperature, and ambient humidity. The bility check algorithm 5620A may further receive as inputs operating parameters (step 5620A3) of the humidifier 5000 such as a heat output of the g element 5220 to the wick 5230 and a flow rate of water to the wick 5230. The plausibility check algorithm 5620A may determine predicted outlet conditions (e.g. humidity/temperature at outlet, as shown in step 5620A4) based on the . In one form, the bility check algorithm 5260 may monitor outlet conditions (step 5620A5), such as a measured temperature at the air outlet 5004 and a measured humidity at the air outlet 5004. The plausibility check algorithm may compare the measured temperature and/or humidity against to test plausibility of the measured temperature and/or the humidity. If the temperature at the air outlet 5004 505809DIV4 and/or the humidity at the air outlet 5004 is found to be implausible (step 5620A6), for example as they deviate more than a threshold amount from a predicted value f respectively, the plausibility check algorithm may indicate a fault condition. It is noted that in other forms of the plausibility check algorithm 5620, , predicted values and measured values may be varied. For example (not shown), the inlet/ambient conditions and outlet conditions may be monitored to determine predicted operating parameters, and to compare the predicted operating parameters with measured operating parameters in order to determine plausibility of the ements. .

For ce, at an absolute ambient humidity of 10 mg/L, at an air flow rate of 35L/min, a predicted absolute humidity of the flow of air at the air outlet 5004 may be 30mg/L. Accordingly, if the water delivery mechanism 5150 has been delivering a water flow rate of 700mg/min, evaporation of the red water would add /min) / (35L/min) = 20mg/L of absolute humidity to the flow of air at the air outlet 5004. However, after a threshold period of time, for example 5 minutes, the te humidity at the air outlet 5004 is below a threshold amount of the target te ty, the plausibility check algorithm may determine that the humidifier 5000 is not ing correctly and indicate a fault ion.

In another form, a plausibility check algorithm 5620 may perform a test cycle to check operation of the humidifier 5000. For instance, the plausibility check algorithm 5620 may change the heat output of the heating element 5220 and/or the water flow rate of the water delivery mechanism 5150 and check a response of the humidifier 5000 using one or more of the humidifier transducers.

In another form, a plausibility check algorithm 5620 may check for correct performance of a component such as a water delivery mechanism 5150, by comparing a water flow rate in comparison to a rate of movement of the water pump 5152.

The plausibility check thms 5620 may be configured to run at one or more of predetermined intervals, predetermined triggers or user/patient requests. For example, the plausibility check algorithm 5620 may be performed at start-up of the humidifier 5000, at monthly intervals, at requests of the patient 1000, at requests from 505809DIV4 a remote location such as a health care provider’s computer, or when the humidity sensor 5516 detects that the output humidity from the humidifier 5000 is below the target ty for over a threshold period of time. In other cases, the plausibility check algorithms 5620 may be ured to be running continuously (or periodically) while the humidifier 5000 is in operation. .5.3.1.3 Pump condition ination thms 5630 In one form, the humidifier 5000 may comprise one or more pump condition determination algorithms 5630. The pump condition determination algorithm may ine, for example, any blockages in the pump 5152 or any fault conditions of the pump 5152 such as an over-temperature condition, an urrent condition or leak. In one form, pump condition determination algorithm(s) may be performed at humidifier start-up (e.g. prior to commencement of therapy and/or humidification) to determine the suitability of the pump 5152 for operation. .5.3.1.4 Fault mitigation algorithms One aspect of the present technology relates to use of fault mitigation algorithms.

In one form, a fault tion algorithm may be ured to respond to outputs of wick condition ination algorithm 5610 and/or the plausibility check algorithms 5620. For instance, the wick condition determination algorithm 5610 may determine a condition of the fier wick 5230 and output a signal indicating that the humidifier wick 5230 may no longer be suitable for use. Then, the fault mitigation algorithm may act to reduce a flow rate of air through the humidifier 5000, reduce a water flow rate from the water delivery mechanism 5150, and/or possibly stop operation of the humidifier 5000 and/or the RPT device 4000. .5.3.2 Humidifier control algorithms .5.3.2.1 Humidification algorithms 5650 According to one aspect, humidification algorithms 5650 may be configured to control components of the humidifier 5000 to manage the humidity of the flow of air delivered from the humidifier 5000. 505809DIV4 In one form, the humidification thm 5650 may receive as inputs one or more target output conditions such as target output humidity or target output temperature, one or more ambient conditions such as ambient humidity or ambient temperature, and/or one or more measured output conditions such as measured output humidity or measured output temperature. Other possible inputs for the fication thm 5650 may include characteristics of an air t 4170 such as its length, or teristics of the patient interface 3000 such as its type, or vent characteristics. In some cases, characteristics of the air circuit 4170 and/or the patient interface 3000 may be input by a user, however in other cases, they may be detected by an identification module or a recognition system, such as that described in a PCT application 0/091462, the entire contents of which is included herewithin by cross-reference. The humidification algorithms 5650 may further use as inputs one or more of a presence of a patient 1000, a flow rate of the flow of air through the air circuit 4170, a pressure gradient of the flow of air, or a breath rate of a patient 1000.

The humidification algorithms 5650 may in one form operate so that the flow of air delivered by the humidifier 5000 is at or close to 100% relative humidity, although others may be possible, such as (but not limited to) 40%, 50% 60%, 70%, 80% or 90%. One advantage of the present technology may include a shortened response time as described above. The humidification algorithm may thus be configured in some forms to only cease operation where a 100% output relative ty is detected, without producing significant, or any, rain-out.

According to another aspect, a humidification thm may be programmed to behave in a near fashion as a response to a change in operating conditions. For instance, the humidification thm may be programmed so that when a mask leak increases e.g. from 5L/min to 10L/min, increasing the total flow rate from 35L/min to n, the heat output from the g element 5220 and the water flow rate from the water delivery mechanism 5150 is increased by a greater amount than 5/35. The response by a humidification algorithm based on a change in operating conditions may be delayed in some cases.

In another aspect, the humidification algorithm 5650 may be configured to determine suitable target conditions according to the ambient conditions, for example without the need for a user (or a patient 1000) to change the d output condition. 505809DIV4 For instance, the humidification algorithm 5650 may direct the humidifier 5000 to output warmer air at a higher humidity where the ambient conditions are colder and drier in comparison to where the ambient conditions are warmer and more humid.

In some forms of the humidification algorithm 5650, the heat output to the humidifier wick 5230 and the water flow rate to the humidifier wick 5230 may be controlled as a function of each other. For instance, where the heat output to the humidifier wick 5230 is limited, such as due to low power bility, the water flow rate to the humidifier wick 5230 may be reduced accordingly. Furthermore, where the water flow rate is d such as where the quantity of water in the reservoir 5110 is d, the heat output to the fier wick 5230 may be reduced accordingly.

In a yet r aspect, the humidification algorithm 5650 may determine target conditions according to one or more preferences and/or therapeutic requirements of the patient 1000. In one form, the fication algorithm 5650 may receive a set of patient preferences through input devices 4220. In another form, the humidification algorithm 5650 may learn a patient’s preference from a usage pattern of the patient 1000 or detection of sleep quality of a patient 1000. 2.2 Humidifier calibration algorithms 5660 In some cases, one or more humidifier calibration algorithms 5660 may be used to verify operation of the humidifier 5000 and/or to calibrate the humidifier 5000. One or more humidifier calibration thms may be performed periodically, or according to triggers such as user requests. For instance, an out-of-calibration operation of the humidifier 5000 may lead to an oversupply of water in comparison to the desired water flow rate, which may lead to introduction of water in the air circuit 4170. Alternatively, an undersupply of water in comparison to the desired water flow rate may lead to overheating of the fier 5000 or discomfort for the patient 1000.

In one form, a humidifier calibration algorithm 5660 may deliver a known water flow rate to a humidifier wick 5230, while varying a heat output to the wick 5230 to analyse one or more responses of the humidifier 5000, for e using the humidifier transducers.

In another form, a humidifier calibration algorithm 5660 may deliver a known heat output to a humidifier wick 5230, while varying a water flow rate to the wick 5230 to analyse one or more responses of the humidifier 5000, for example using the humidifier transducers. 2.3 Foreign matter management algorithms 5670 As described above, formation, collection and/or build-up on foreign matter such as particulates may occur on the humidifier wick 5230, which may adversely affect a performance of the wick 5230. According to one aspect, one or more foreign matter management algorithms may be used to control the on and/or rate of foreign matter build-up on the wick 5230.

In some cases, foreign matter may collect on the humidifier wick at the greatest rate where the wick 5230 dries out completely. For instance, at a water ry 5230_WB of the water retained by the wick 5230, as shown in Fig. 14. In one form, a foreign matter management thm 5670 may manage a location and/or pattern of a water ry 5230_WB for example away from an area of detected low water capacity. The foreign matter management algorithm 5670 may achieve this goal by controlling one or more of the heat output onto the humidifier wick 5230, a water flow rate onto the humidifier wick 5230 or a water bution pattern within the humidifier wick 5230.

According to r aspect, a foreign matter management algorithm may be configured to determine a quality of water, such as a foreign matter content in the water. In one form, a conductivity of water may be measured to determine the foreign matter content in the water. In one form, electrodes in contact with the water may be placed in the humidifier 5000 (e.g. in the reservoir 5110, water delivery ism 5150, or in the wick 5230) to measure resistivity of the water. In some forms, the electrodes may be placed in the wick 5230 so that the resistivity measured will te resistivity of the wick and the water therein, where a high resistivity may indicate a corresponding high level of foreign matter build-up in the wick. .5.3.2.4 Wick cleaning algorithms 5680 The humidifier 5000 may comprise wick cleaning algorithms 5680 configured to clean the humidifier wick 5230, for reducing the amount of foreign matter and/or any rden on the wick 5230.

In one form, a wick cleaning algorithm 5680 may operate to rinse the fier wick 5230 with a supply of water and/or a cleaning agent. Additionally, or alternatively, the wick cleaning algorithm 5680 may dry the wick 5230, in some cases at a temperature higher than an operating temperature.

In another form, a wick cleaning algorithm 5680 may be configured to activate where a cleaning adapter is coupled to the humidifier 5000. One advantage of this form may be to prevent use of the humidifier 5000 by the patient 1000 while the wick cleaning algorithm 5680 is activated. In some cases, the ng adapter may comprise a cleaning agent which may be ed into the humidifier wick 5230 while the wick cleaning algorithm 5680 is active.

A wick cleaning algorithm 5680 may be configured to operate in some forms after cessation of therapy. In some cases, the RPT device 4000 and/or a humidifier 5000 may be arranged with a battery to enable operation of the wick ng algorithm 5680 after power has been switched off. .5.3.3 Patient feedback algorithms 5690 The humidifier 5000 may comprise one or more patient feedback algorithms 5690 for relaying information and/or ing recommendations to the t 1000.

Patient feedback algorithms 5690 may, in some forms, inform the t 1000 of one or more outputs from the humidifier algorithms described above.

Examples of information provided to a patient 1000 by a patient feedback algorithm 5690 may include a condition of the humidifier wick 5230, such as its remaining life or a quality of the water, or any ous activity of the humidifier 5000, or an indication of a fault, such as detection of a missing water reservoir 5110. In some cases, a patient feedback algorithm 5690 may simply indicate to a patient 1000 or a ver that the humidifier wick 5230 may require to be washed. 505809DIV4 .6 GLOSSARY 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 t technology, alternative definitions may apply. .6.1 General Air: ‘Air’ in the present disclosure will be taken to include breathable gases. In certain forms of the present logy, air supplied to a patient may be atmospheric air, and in other forms of the t technology atmospheric air may be supplemented with oxygen.

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 t. For example, ambient humidity with respect to a humidifier may be the humidity of air immediately surrounding the humidifier.

Continuous Positive Airway Pressure (CPAP): CPAP ent will be taken to mean the application of a supply of air or air to the entrance to the airways at a pressure that is continuously positive with respect to here, and preferably approximately nt through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will vary by a few centimeters of water within a single respiratory cycle, for example being higher during inhalation and lower during exhalation. In some forms, the re at the entrance to the airways will be slightly higher during tion, and slightly lower during tion. 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 l upper airway obstruction, and decreased in the absence of indications of partial upper airway obstruction. .6.2 Aspects of RPT devices Air circuit: A conduit or tube constructed and arranged in use to deliver a supply of air between an RPT device and a patient interface. In particular, the air circuit may be in fluid connection with the outlet of the tic block and the patient interface. The air circuit may be referred to as 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. .7 OTHER REMARKS A portion of the disclosure of this patent document contains material which is subject to copyright protection. The ght owner has no ion to the ile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all ght rights whatsoever.

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.

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 imated, 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.

Unless d otherwise, all technical and scientific terms used herein have the same g as commonly understood by one of ordinary skill in the art to which this technology belongs. gh any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, a limited number of the exemplary methods and materials are described herein.

When a particular material is identified as being ably used to construct a component, obvious alternative materials with similar properties may be 505809DIV4 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.

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.

All publications mentioned herein are incorporated by reference to disclose and describe the methods and/or materials which are the subject of those publications. The publications discussed herein are ed 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 te such publication by virtue of prior invention. Further, the dates of publication ed may be ent from the actual ation dates, which may need to be independently confirmed.

Moreover, in reting the sure, all terms should be reted in the broadest reasonable manner consistent with the context. In ular, 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.

The subject headings used in the detailed ption 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.

Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely rative of the principles and ations 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 " 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 505809DIV4 steps in the methodologies may be described or illustrated in an order, such an ordering is not ed. Those skilled in the art will recognize that such ordering may be modified and/or aspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous cations may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the technology. .8 REFERENCE SIGNS LIST patient 1000 bed partner 1100 patient interface 3000 seal-forming structure 3100 plenum chamber 3200 ising structure 3300 connection port 3600 forehead support 3700 RPT device 4000 external housing 4010 upper portion 4012 lower portion 4014 panel 4015 s 4016 handle 4018 pneumatic block 4020 pneumatic component 4100 air filter 4110 inlet air filter 4112 outlet air filter 4114 muffler 4120 inlet muffler 4122 outlet muffler 4124 pressure device 4140 blower 4142 motor 4144 back valve 4160 air circuit 4170 supplemental oxygen 4180 electrical component 4200 PCBA 4202 power supply 4210 input device 4220 central controller 4230 clock 4232 therapy device controller 4240 protection circuit 4250 memory 4260 transducer 4270 pressure transducer 4272 flow ucer 4274 motor speed sensor 4276 data communication interface 4280 remote external communication network 4282 local external communication network 4284 remote external device 4286 505809DIV4 local external device 4288 output device 4290 display driver 4292 display 4294 humidifier 5000 air inlet 5002 air outlet 5004 water reservoir 5110 water volume detector 5112 water delivery mechanism 5150 water pump 5152 water delivery conduit 5154 mechanism 5156 water check valve 5158 humidification r 5200 outer housing 5202 outer housing inlet n 5202a outer housing heater cover portion 5202b outer housing outlet portion 5202c inner housing 5204 water feed inlet 5206 air flow baffle 5208 water filter 5214 heating element 5220 reservoir heating element 5221 humidifier wick 5230 wick dry region 5230_D wick wet region 5230_W water boundary 5230_WB wick first layer 5230a wick second layer 5230b wick frame 5232 wick frame grip surface 5232_G wick locator 5233 humidifier filter 5240 plausibility check algorithm 5260 flow sensor 5512 temperature sensor 5514 humidity sensor 5516 humidifier controller 5550 humidifier algorithm 5600 wick condition determination algorithm 5610 plausibility check algorithm 5620 pump condition determination algorithm 5630 humidification algorithm 5650 humidifier calibration algorithm 5660 foreign matter management algorithm 5670 wick ng thm 5680 patient ck algorithm 5690 example wick condition determination algorithm 5610A example wick condition determination algorithm step 1 5610A1 example wick condition determination algorithm step 2 5610A2 505809DIV4 example wick condition determination algorithm step 3 5610A3 example wick condition determination algorithm step 4 5610A4 example wick condition determination thm step 5 5610A5 e wick condition determination algorithm step 6 5610A6 example wick condition determination algorithm 5610B example wick condition determination algorithm step 1 5610B1 example wick condition determination algorithm step 2 5610B2 example wick condition determination algorithm step 3 5160B3 example wick condition determination algorithm step 4 5160B4 example wick condition determination algorithm step 5 5610B5 example wick condition determination algorithm step 6 5610B6 example wick condition determination algorithm step 7 5610B7 e wick condition ination algorithm 5610C example wick condition determination algorithm step 1 5610C1 example wick condition determination algorithm step 2 5610C2 example wick condition determination algorithm step 3 5610C3 e wick condition determination thm step 4 5610C4 e wick condition determination algorithm step 5 5610C5 505809DIV4 example wick condition determination algorithm step 6 5610C6 example wick condition determination algorithm step 7 5610C7 example plausibility check algorithm 5620A example bility check algorithm step 1 5620A1 e plausibility check algorithm step 2 5620A2 example plausibility check algorithm step 3 5620A3 example plausibility check algorithm step 4 5620A4 example plausibility check algorithm step 5 5620A5 example bility check algorithm step 6 5620A6 505809DIV4 6

Claims

1. A method for lling a location and/or a rate of foreign matter build-up on a humidifier wick of a humidifier, the humidifier sing the humidifier wick, a heating element to apply heat to the humidifier wick, a water delivery mechanism to deliver water to the humidifier wick, and a controller configured to e one more signals and/or generate one or more signals, and the humidifier wick being configured to retain a volume of water, the method comprising: controlling a location and/or a pattern of a water boundary on the humidifier wick of the fier by varying, with the ller, at least one of: a heat output from the heating element onto the fier wick; a water flow rate from the water delivery mechanism onto the humidifier wick; and a water distribution pattern within the humidifier wick by adjusting the heat output from the heating element and/or the water flow rate from the water delivery, wherein controlling the location and/or the pattern of the water boundary causes foreign matter to build up at a predetermined region of the humidifier wick based on the location and/or the pattern of the water boundary.

2. The method as claimed in claim 1, further comprising: ing a foreign matter content of the water with a sensor; and determining a quality of the water with the ller based on the foreign matter content detected by the sensor.

3. The method as claimed in claim 2, wherein detecting the foreign matter content of the water with the sensor further comprises measuring a conductivity of the water with the sensor. 505809DIV4

4. The method as claimed in claim 2, wherein detecting the foreign matter t of the water with the sensor further comprises measuring a resistivity of the water with electrodes in contact with the water.

5. The method as claimed in claim 4, wherein the electrodes are located in the humidifier wick and the water contained in the humidifier wick, and wherein, the resistivity measured by the electrodes is ly correlated to a level of foreign matter build-up in the humidifier wick. 4000 5000 4170 3000