Patent Description:
The airways include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the inhaled air into the venous blood and carbon dioxide to move in the opposite direction. The trachea divides into right and left main bronchi, which further divide eventually into terminal bronchioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further divisions of the airways lead to the respiratory bronchioles, and eventually to the alveoli. The alveolated region of the lung is where the gas exchange takes place, and is referred to as the respiratory zone. See "<NPL>.

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

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing (SDB), is characterised by events including occlusion or obstruction of the upper air passage during sleep. It results from a combination of an abnormally small upper airway and the normal loss of muscle tone in the region of the tongue, soft palate and posterior oropharyngeal wall during sleep. The condition causes the affected patient to stop breathing for periods typically of <NUM> to <NUM> seconds in duration, sometimes <NUM> to <NUM> times per night. It often causes excessive daytime somnolence, and it may cause cardiovascular disease and brain damage. The syndrome is a common disorder, particularly in middle aged overweight males, although a person affected may have no awareness of the problem. See <CIT>).

Cheyne-Stokes Respiration (CSR) is another form of sleep disordered breathing. CSR is a disorder of a patient's respiratory controller in which there are rhythmic alternating periods of waxing and waning ventilation known as CSR cycles. CSR is characterised by repetitive de-oxygenation and re-oxygenation of the arterial blood. It is possible that CSR is harmful because of the repetitive hypoxia. In some patients CSR is associated with repetitive arousal from sleep, which causes severe sleep disruption, increased sympathetic activity, and increased afterload. See <CIT>).

Respiratory failure is an umbrella term for respiratory disorders in which the lungs are unable to inspire sufficient oxygen or exhale sufficient CO<NUM> to meet the patient's needs. Respiratory failure may encompass some or all of the following disorders.

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

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

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a group of lower airway diseases that have certain characteristics in common. These include increased resistance to air movement, extended expiratory phase of respiration, and loss of the normal elasticity of the lung. Examples of COPD are emphysema and chronic bronchitis. COPD is caused by chronic tobacco smoking (primary risk factor), occupational exposures, air pollution and genetic factors. Symptoms include: dyspnea on exertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses many diseases and ailments that impair the functioning of the muscles either directly via intrinsic muscle pathology, or indirectly via nerve pathology. Some NMD patients are characterised by progressive muscular impairment leading to loss of ambulation, being wheelchair-bound, swallowing difficulties, respiratory muscle weakness and, eventually, death from respiratory failure. Neuromuscular disorders can be divided into rapidly progressive and slowly progressive: (i) Rapidly progressive disorders: Characterised by muscle impairment that worsens over months and results in death within a few years (e.g. Amyotrophic lateral sclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers); (ii) Variable or slowly progressive disorders: Characterised by muscle impairment that worsens over years and only mildly reduces life expectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic muscular dystrophy). Symptoms of respiratory failure in NMD include: increasing generalised weakness, dysphagia, dyspnea on exertion and at rest, fatigue, sleepiness, morning headache, and difficulties with concentration and mood changes.

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

A range of therapies have been used to treat or ameliorate such conditions. Furthermore, otherwise healthy individuals may take advantage of such therapies to prevent respiratory disorders from arising. However, these have a number of shortcomings.

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

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

Continuous Positive Airway Pressure (CPAP) therapy has been used to treat Obstructive Sleep Apnea (OSA). The mechanism of action is that continuous positive airway pressure acts as a pneumatic splint and may prevent upper airway occlusion, such as by pushing the soft palate and tongue forward and away from the posterior oropharyngeal wall. Treatment of OSA by CPAP therapy may be voluntary, and hence patients may elect not to comply with therapy if they find devices used to provide such therapy one or more of: uncomfortable, difficult to use, expensive and aesthetically unappealing.

Non-invasive ventilation (NIV) provides ventilatory support to a patient through the upper airways to assist the patient breathing and/or maintain adequate oxygen levels in the body by doing some or all of the work of breathing. The ventilatory support is provided via a non-invasive patient interface. NIV has been used to treat CSR and respiratory failure, in forms such as OHS, COPD, NMD and Chest Wall disorders. In some forms, the comfort and effectiveness of these therapies may be improved.

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

Not all respiratory therapies aim to deliver a prescribed therapeutic pressure. Some respiratory therapies aim to deliver a prescribed respiratory volume, by delivering an inspiratory flow rate profile over a targeted duration, possibly superimposed on a positive baseline pressure. In other cases, the interface to the patient's airways is 'open' (unsealed) and the respiratory therapy may only supplement the patient's own spontaneous breathing with a flow of conditioned or enriched gas. In one example, High Flow therapy (HFT) is the provision of a continuous, heated, humidified flow of air to an entrance to the airway through an unsealed or open patient interface at a "treatment flow rate" that may be held approximately constant throughout the respiratory cycle. The treatment flow rate is nominally set to exceed the patient's peak inspiratory flow rate. HFT has been used to treat OSA, CSR, respiratory failure, COPD, and other respiratory disorders. One mechanism of action is that the high flow rate of air at the airway entrance improves ventilation efficiency by flushing, or washing out, expired CO<NUM> from the patient's anatomical deadspace. Hence, HFT is thus sometimes referred to as a deadspace therapy (DST). Other benefits may include the elevated warmth and humidification (possibly of benefit in secretion management) and the potential for modest elevation of airway pressures. As an alternative to constant flow rate, the treatment flow rate may follow a profile that varies over the respiratory cycle.

Another form of flow therapy is long-term oxygen therapy (LTOT) or supplemental oxygen therapy. Doctors may prescribe a continuous flow of oxygen enriched gas at a specified oxygen concentration (from <NUM>%, the oxygen fraction in ambient air, to <NUM>%) at a specified flow rate (e.g., <NUM> litre per minute (LPM), <NUM> LPM, <NUM> LPM, etc.) to be delivered to the patient's airway.

For certain patients, oxygen therapy may be combined with a respiratory pressure therapy or HFT by adding supplementary oxygen to the pressurised flow of air. When oxygen is added to respiratory pressure therapy, this is referred to as RPT with supplementary oxygen. When oxygen is added to HFT, the resulting therapy is referred to as HFT with supplementary oxygen.

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

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

Another form of therapy system is a mandibular repositioning device.

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

Air pressure generators are known in a range of applications, e.g. industrial-scale ventilation systems. However, air pressure generators for medical applications have particular requirements not fulfilled by more generalised air pressure generators, such as the reliability, size and weight requirements of medical devices. In addition, even devices designed for medical treatment may suffer from shortcomings, pertaining to one or more of: comfort, noise, ease of use, efficacy, size, weight, manufacturability, cost, and reliability.

An example of the special requirements of certain RPT devices is acoustic noise.

Table of noise output levels of prior RPT devices (one specimen only, measured using test method specified in ISO <NUM> in CPAP mode at <NUM> cmH<NUM>O).

One known RPT device used for treating sleep disordered breathing is the S9 Sleep Therapy System, manufactured by ResMed Limited. Another example of an RPT device is a ventilator. Ventilators such as the ResMed Stellar™ Series of Adult and Paediatric Ventilators may provide support for invasive and non-invasive non-dependent ventilation for a range of patients for treating a number of conditions such as but not limited to NMD, OHS and COPD.

The ResMed Elisée™ <NUM> ventilator and ResMed VS III™ ventilator may provide support for invasive and non-invasive dependent ventilation suitable for adult or paediatric patients for treating a number of conditions. These ventilators provide volumetric and barometric ventilation modes with a single or double limb circuit. RPT devices typically comprise a pressure generator, such as a motor-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 described above.

RPT devices may include for example, a high flow therapy device configured to provide a high flow therapy. In this regard, some respiratory therapies may aim to deliver a prescribed respiratory volume, by delivering an inspiratory flow rate profile over a targeted duration, possibly superimposed on a positive baseline pressure. In other cases, the interface to the patient's airways is 'open' (unsealed) and the respiratory therapy may only supplement the patient's own spontaneous breathing with a flow of conditioned or enriched gas. In one example, High Flow therapy (HFT) is the provision of a continuous, heated, humidified flow of air to an entrance to the airway through an unsealed or open patient interface at a "treatment flow rate" that is held approximately constant throughout the respiratory cycle. The treatment flow rate is nominally set to exceed the patient's peak inspiratory flow rate. HFT has been used to treat OSA, CSR, respiratory failure, COPD, and other respiratory disorders. One mechanism of action is that the high flow rate of air at the airway entrance improves ventilation efficiency by flushing, or washing out, expired CO<NUM> from the patient's anatomical deadspace. Hence, HFT is thus sometimes referred to as a deadspace therapy (DST). Other benefits may include the elevated warmth and humidification (possibly of benefit in secretion management) and the potential for modest elevation of airway pressures. As an alternative to constant flow rate, the treatment flow rate may follow a profile that varies over the respiratory cycle.

The designer of a device may be presented with an infinite number of choices to make. Design criteria often conflict, meaning that certain design choices are far from routine or inevitable. Furthermore, the comfort and efficacy of certain aspects may be highly sensitive to small, subtle changes in one or more parameters.

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

Delivery of a flow of air without humidification may cause drying of airways. The use of a humidifier with an RPT device and the patient interface produces humidified gas that minimizes drying of the nasal mucosa and increases patient airway comfort. In addition in cooler climates, warm air applied generally to the face area in and about the patient interface is more comfortable than cold air. Humidifiers therefore often have the capacity to heat the flow of air was well as humidifying it.

A range of artificial humidification devices and systems are known, however they may not fulfil the specialised requirements of a medical humidifier.

Medical humidifiers are used to increase humidity and/or temperature of the flow of air in relation to ambient air when required, typically where the patient may be asleep or resting (e.g. at a hospital). A medical humidifier for bedside placement may be small. A medical humidifier may be configured to only humidify and/or heat the flow of air delivered to the patient without humidifying and/or heating the patient's surroundings. Room-based systems (e.g. a sauna, an air conditioner, or an evaporative cooler), for example, may also humidify air that is breathed in by the patient, however those systems would also humidify and/or heat the entire room, which may cause discomfort to the occupants. Furthermore medical humidifiers may have more stringent safety constraints than industrial humidifiers.

While a number of medical humidifiers are known, they can suffer from one or more shortcomings. Some medical humidifiers may provide inadequate humidification, some are difficult or inconvenient to use by patients. Additionally, patient error or accident can result in liquids spilling from the tub of conventional humidifiers, that liquid subsequently coming into contact with electrical or delicate mechanical components of the RPT device. This can result in injury to the patient and / or malfunction of the device. A need therefore exists to protect the electrical and mechanical components of RPT devices from the ingress of water, particularly when connected to humidifiers.

Experts in this field have recognized that exercise for respiratory failure patients provides long term benefits that slow the progression of the disease, improve quality of life and extend patient longevity. Most stationary forms of exercise like tread mills and stationary bicycles, however, are too strenuous for these patients. As a result, the need for mobility has long been recognized. Until recently, this mobility has been facilitated by the use of small compressed oxygen tanks or cylinders mounted on a cart with dolly wheels. The disadvantage of these tanks is that they contain a finite amount of oxygen and are heavy, weighing about <NUM> pounds when mounted.

Oxygen concentrators have been in use for about <NUM> years to supply oxygen for respiratory therapy. Traditional oxygen concentrators have been bulky and heavy making ordinary ambulatory activities with them difficult and impractical. Recently, companies that manufacture large stationary oxygen concentrators began developing portable oxygen concentrators (POCs). The advantage of POCs is that they can produce a theoretically endless supply of oxygen. In order to make these devices small for mobility, the various systems necessary for the production of oxygen enriched gas are condensed. POCs seek to utilize their produced oxygen as efficiently as possible, in order to minimise weight, size, and power consumption. This may be achieved by delivering the oxygen as series of pulses or "boli", each bolus timed to coincide with the start of inspiration. This therapy mode is known as pulsed or demand (oxygen) delivery (POD), in contrast with traditional continuous flow delivery more suited to stationary oxygen concentrators.

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

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

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

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

A further aspect of the present technology is to provide a liquid diversion assembly suitable for use between, for example, an RPT device and a humidifier, comprising multiple panels. These panels are constructed such that when they are connected they form one or more internal passageways. These passageways are configured to divert liquid from the humidifier away from the inner components of the RPT device and out through the RPT device housing into the ambient environment. The passageways may be formed around any inlets/outlets, coupling components or electrical connectors in various configurations.

An aspect of one form of the present technology is a liquid diversion assembly for a medical device that includes a housing. The liquid diversion assembly comprises an end cap in association with the housing, the end cap comprising at least one aperture for selective coupling with a compatible accessory, wherein the end cap comprises at least one internal fluid passageway in fluid communication with the at least one aperture to divert liquid to an exterior of the housing.

In examples, the end cap may comprise a plurality of panels, each panel having an interior surface and an exterior surface, wherein the plurality of panels are joined together to form the end cap and define the at least one internal fluid passageway therebetween. In examples the plurality of panels comprises a proximal panel proximal to the medical device in use, comprising a first interior surface and a first exterior surface, and a distal panel distal to the medical device in use, comprising a second interior surface and a second exterior surface. In examples the liquid diversion assembly comprises at least one wall extending between the first interior surface and the second interior surface, wherein the internal fluid passageway is at least in part defined by the at least one wall, the first interior surface, and the second interior surface.

In examples the proximal panel comprises at least one recess in the first interior surface, wherein the at least one aperture is between the second exterior surface and the second interior surface of the distal panel, and wherein the at least one recess is substantially aligned with the at least one aperture. In examples the at least one wall extends along the first interior surface and the second interior surface to substantially surround the at least one recess, wherein the at least one wall comprises a gap in a position inferior to the at least one recess, configured to permit flow of liquid from the internal fluid passageway to the exterior of the end cap. In examples an inferior surface of the at least one recess is angled from a superior position to an inferior position at the first interior surface.

In examples, the proximal panel may comprise a guide protrusion surrounding each one of the at least one recesses, wherein the guide protrusion projects from the first interior surface towards the second interior surface, wherein an air gap is retained between the guide protrusion and the second interior surface. In examples the guide protrusion may comprise a radially outward facing surface and a radially inward facing surface meeting at an apex. In examples each guide protrusion may comprises a raised base surrounding the recess, and a guide protrusion extending from the raised base. In examples a plateau portion may be provided between a radially outward edge of the raised base and the guide protrusion.

In examples, the at least one wall may comprise a first wall extending from the first interior surface, and a second wall extending from the second interior surface, wherein the proximal panel and the distal panel are configured such that when connected the first wall and the second wall cooperate to form the internal fluid passageway.

In examples, the panels may be joined to form a unitary part. In examples, the panels may be joined by mechanical means (for example using fasteners, and/or engineering fit), and/or bonding (for example thermal bonding such as heat staking, or ultrasonic welding).

In examples, the compatible accessory may be a humidifier. In examples, the medical device may be a ventilator.

An aspect of one form of the present technology is an apparatus for supplying a flow of breathable gas at a positive pressure for respiratory therapy, wherein the apparatus comprises: a pressure generator for generating the flow of breathable gas and supplying the flow to an outlet; a housing which contains at least the pressure generator; and a liquid diversion assembly substantially as described herein, wherein the end cap of the liquid diversion assembly is configured to be secured relative to the housing containing at least the pressure generator.

An aspect of one form of the present technology is a respiratory treatment system, comprising an apparatus for supplying a flow of breathable gas at a positive pressure for respiratory therapy substantially as described herein, and a humidifier apparatus to change the absolute humidity of a flow of air for delivery to an entrance of the airways of a patient, the change being compared to the absolute humidity of ambient air, wherein the humidifier apparatus is configured to be selectively coupled to the apparatus for supplying a flow of breathable gas via the at least one aperture of the end cap.

In examples, the apparatus comprises an end cap in association with the housing. In examples the end cap is configured to selectively couple with the chamber and reservoir. In examples the end cap is positioned so that it forms a seal in conjunction with the housing. In examples the end cap forms a physical barrier between the pneumatic block and the optional chamber and reservoir.

Patent documents <CIT> and <CIT> are hereby acknowledged.

The following description is provided in relation to various examples which may share one or more common characteristics and/or features. It is to be understood that one or more features of any one example may be combinable with one or more features of another example or other examples. In addition, any single feature or combination of features in any of the examples may constitute a further example.

Respiratory humidifiers are available in many forms and may be a standalone device that is coupled to an RPT device via an air circuit, is integrated with the RPT device or 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 humidity and temperature to the air so that the patient will be comfortable. In examples, humidifiers comprise a water reservoir or tub having a capacity of several hundred milliliters (ml), a heating element 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 flow generator or 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 incorporated 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 CPAP devices respectively.

Other humidifiers may also be used such as a bubble or diffuser humidifier, a jet humidifier or a wicking 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. A wicking humidifier uses a water absorbing material, such as sponge or paper, to absorb water by capillary action. The water absorbing material is placed within or adjacent at least a portion of the air flow path to allow evaporation of the water in the absorbing material to be taken up into the air flow.

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 supplying heated water to the large surface area in a second opposite direction. The ResMed HumiCare™ D900 humidifier may be used with a range of invasive and non-invasive ventilators.

In one form of the present technology there is provided a humidifier <NUM> (e.g. as shown in <FIG>) to change the absolute humidity of air or gas for delivery to a patient relative to ambient air. Typically, the humidifier <NUM> is used to increase the absolute humidity and increase the temperature of the flow of air (relative to ambient air) before delivery to the patient's airways.

The humidifier <NUM> may comprise a humidifier reservoir <NUM>, a humidifier inlet <NUM> to receive a flow of air, and a humidifier outlet <NUM> to deliver a humidified flow of air. In some forms, as shown in <FIG>, an inlet and an outlet of the humidifier reservoir <NUM> may be the humidifier inlet <NUM> and the humidifier outlet <NUM> respectively. The humidifier <NUM> may further comprise a humidifier base <NUM>, which may be adapted to receive the humidifier reservoir <NUM> and comprise a heating element <NUM>.

According to one arrangement, the humidifier <NUM> may comprise a water reservoir <NUM> configured to hold, or retain, a volume of liquid (e.g. water) to be evaporated for humidification of the flow of air. The water reservoir <NUM> may be configured to hold a predetermined maximum volume of water in order to provide adequate humidification for at least the duration of a respiratory therapy session, such as one evening of sleep. Typically, the reservoir <NUM> is configured to hold several hundred millilitres of water, e.g. <NUM> millilitres (ml), <NUM>, <NUM> or <NUM>. In other forms, the humidifier <NUM> may be configured to receive a supply of water from an external water source such as a building's water supply system.

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

According to one form, the reservoir <NUM> may be removable from the humidifier <NUM>, for example in a lateral direction as shown in <FIG>.

The reservoir <NUM> may also be configured to discourage egress of liquid therefrom, such as when the reservoir <NUM> is displaced and/or rotated from its normal, working orientation, such as through any apertures and/or in between its subcomponents. As the flow of air to be humidified by the humidifier <NUM> is typically pressurised, the reservoir <NUM> may also be configured to prevent losses in pneumatic pressure through leak and/or flow impedance.

According to one arrangement, the reservoir <NUM> comprises a conductive portion <NUM> configured to allow efficient transfer of heat from the heating element <NUM> to the volume of liquid in the reservoir <NUM>. In one form, the conductive portion <NUM> may be arranged as a plate, although other shapes may also be suitable. All or a part of the conductive portion <NUM> may be made of a thermally conductive material such as aluminium (e.g. approximately <NUM> thick, such as <NUM>, <NUM>, <NUM> or <NUM>), another heat conducting metal or some plastics. In some cases, suitable heat conductivity may be achieved with less conductive materials of suitable geometry.

In one form, the humidifier <NUM> may comprise a humidifier reservoir dock <NUM> (as shown in <FIG>) configured to receive the humidifier reservoir <NUM>. In some arrangements, the humidifier reservoir dock <NUM> may comprise a locking feature such as a locking lever <NUM> configured to retain the reservoir <NUM> in the humidifier reservoir dock <NUM>.

The humidifier reservoir <NUM> may comprise a water level indicator <NUM> as shown in <FIG>. In some forms, the water level indicator <NUM> may provide one or more indications to a user such as the patient <NUM> or a care giver regarding a quantity of the volume of water in the humidifier reservoir <NUM>. The one or more indications provided by the water level indicator <NUM> may include an indication of a maximum, predetermined volume of water, any portions thereof, such as <NUM>%, <NUM>% or <NUM>% or volumes such as <NUM>, <NUM> or <NUM>.

The humidifier <NUM> may comprise one or more humidifier transducers (sensors) <NUM> instead of, or in addition to, transducers <NUM> described above. Humidifier transducers <NUM> may include one or more of an air pressure sensor <NUM>, an air flow rate transducer <NUM>, a temperature sensor <NUM>, or a humidity sensor <NUM> as shown in <FIG>. A humidifier transducer <NUM> may produce one or more output signals which may be communicated to a controller such as the central controller <NUM> and/or the humidifier controller <NUM>. In some forms, a humidifier transducer may be located externally to the humidifier <NUM> (such as in the air circuit <NUM>) while communicating the output signal to the controller.

One or more pressure transducers <NUM> may be provided to the humidifier <NUM> in addition to, or instead of, a pressure sensor <NUM> provided in the RPT device <NUM>.

One or more flow rate transducers <NUM> may be provided to the humidifier <NUM> in addition to, or instead of, a flow rate sensor <NUM> provided in the RPT device <NUM>.

The humidifier <NUM> may comprise one or more temperature transducers <NUM>. The one or more temperature transducers <NUM> may be configured to measure one or more temperatures such as of the heating element <NUM> and/or of the flow of air downstream of the humidifier outlet <NUM>. In some forms, the humidifier <NUM> may further comprise a temperature sensor <NUM> to detect the temperature of the ambient air.

In one form, the humidifier <NUM> may comprise one or more humidity sensors <NUM> to detect a humidity of a gas, such as the ambient air. The humidity sensor <NUM> may be placed towards the humidifier outlet <NUM> in some forms to measure a humidity of the gas delivered from the humidifier <NUM>. The humidity sensor may be an absolute humidity sensor or a relative humidity sensor.

A heating element <NUM> may be provided to the humidifier <NUM> in some cases to provide a heat input to one or more of the volume of water in the humidifier reservoir <NUM> and/or to the flow of air. The heating element <NUM> may comprise a heat generating component such as an electrically resistive heating track. One suitable example of a heating element <NUM> is a layered heating element such as one described in the <CIT>.

In some forms, the heating element <NUM> may be provided in the humidifier base <NUM> where heat may be provided to the humidifier reservoir <NUM> primarily by conduction as shown in <FIG>.

According to one arrangement of the present technology, a humidifier <NUM> may comprise a humidifier controller <NUM> as shown in <FIG>. In one form, the humidifier controller <NUM> may be a part of the central controller <NUM>. In another form, the humidifier controller <NUM> may be a separate controller, which may be in communication with the central controller <NUM>.

In one form, the humidifier controller <NUM> may receive as inputs measures of properties (such as temperature, humidity, pressure and/or flow rate), for example of the flow of air, the water in the reservoir <NUM> and/or the humidifier <NUM>. The humidifier controller <NUM> may also be configured to execute or implement humidifier algorithms and/or deliver one or more output signals.

As shown in <FIG>, the humidifier controller <NUM> may comprise one or more controllers, such as a central humidifier controller <NUM>, a heated air circuit controller <NUM> configured to control the temperature of a heated air circuit <NUM> and/or a heating element controller <NUM> configured to control the temperature of a heating element <NUM>.

According to one aspect of the present technology, a humidifier <NUM> may have a body comprising an external housing <NUM>. In one example, the housing <NUM> may be formed in two parts, an upper portion <NUM> and a lower portion <NUM>. The body of humidifier <NUM> further comprises a chassis <NUM>.

Reference to a chassis herein should be understood to mean a supporting frame of a structure - i.e. a structural element configured to support one or more other components, more particularly one or more internal components of the humidifier <NUM>. Reference to a housing should be understood to mean an element that covers or protects other components of a structure. In one example the housing <NUM> is provided to at least partially cover or protect the chassis <NUM>. In alternative examples, the humidifier <NUM> may comprise a housing <NUM> configured to act as a chassis <NUM>. In alternative examples, the humidifier <NUM> may comprise a chassis <NUM> without a separate housing per se.

In examples, the humidifier <NUM> comprises a removable container in the form of water reservoir <NUM>. The chassis <NUM> is configured to locate and support the removable reservoir <NUM> in use. In the example shown in <FIG>, the reservoir <NUM> is inserted and removed from an end of the humidifier. In alternative examples, the reservoir <NUM> may be removed from a side of the humidifier <NUM> (i.e. laterally), or from above or below (i.e. vertically). <CIT> describes exemplary arrangements for a humidifier having a removable water reservoir.

In alternative examples, the chassis <NUM> may comprise a chamber which functions as the water reservoir <NUM> - i.e. is integrated with the chassis <NUM> rather than being removable.

There are various circumstances in which water may pass through the chamber inlet port <NUM> from the reservoir <NUM>, including knocking of the humidifier <NUM> or a stand on which it sits to produce a sloshing effect, or tipping of the humidifier <NUM> as it is shifted or re-oriented.

According to one aspect of the present technology, as shown in <FIG>, the humidifier <NUM> comprises a closure element in the form of a chassis cap <NUM>. In this example the chassis cap <NUM> is configured to seal against the humidifier housing <NUM> and the humidifier chassis <NUM>, as described further below.

In examples, the chassis cap <NUM> comprises an air inlet port <NUM> configured to be connected to a source of a flow of air at positive pressure, for example RPT device <NUM>.

In examples, there is provided a gas flow path between the air inlet port <NUM> and the chamber inlet port <NUM>, which in some configurations forms a liquid trap <NUM> for retention of a volume of water spilled through the chamber inlet port <NUM>.

There are various circumstances in which water may pass through the chamber inlet port <NUM> from the reservoir <NUM>, including knocking of the humidifier <NUM> or a stand on which it sits to produce a sloshing effect, or tipping of the humidifier <NUM> as it is shifted or re-oriented. The liquid trap <NUM> is provided to retain a volume of this spilled water to reduce the likelihood of water reaching other components of the system upstream, more particularly the RPT device <NUM>.

An advantage of the liquid diversion assembly embodiments described herein is that they provide a simple, cost effective and user friendly mechanism to prevent damage to the RPT device which may result from such "sloshing" or "tipping" of the humidifier that causes liquid to flow from the reservoir <NUM> via the chamber inlet port <NUM> and into the pneumatic block <NUM> which houses the motor <NUM> and various sensors, along with electrical supply. This flow of liquid may be via either direct sloshing, or through leak in the non-watertight connections in the air inlet path <NUM>, or both.

In one form, the present technology comprises a method for treating a respiratory disorder comprising applying positive pressure to the entrance of the airways of a patient <NUM>.

In one form, the present technology comprises a respiratory therapy system for treating a respiratory disorder. The respiratory therapy system may comprise an RPT device <NUM> for supplying a flow of air to the patient <NUM> via an air circuit <NUM> and a patient interface <NUM>.

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

In one form, the RPT device <NUM> is constructed and arranged to be capable of delivering a flow of air in a range of -<NUM>/min to +<NUM>/min while maintaining a positive pressure of at least <NUM> cmH<NUM>O, or at least 10cmH<NUM>O, or at least <NUM> cmH<NUM>O.

The RPT device may have an external housing <NUM>, formed in two parts, an upper portion <NUM> and a lower portion <NUM>. Furthermore, the external housing <NUM> may comprise one or more panel(s) <NUM>. The RPT device <NUM> comprises a chassis <NUM> that supports one or more internal components of the RPT device <NUM>. The RPT device <NUM> may comprise a handle <NUM>.

The pneumatic path of the RPT device <NUM> may comprise one or more air path items, e.g., an inlet air filter <NUM>, an inlet muffler <NUM>, a pressure generator <NUM> capable of supplying air at positive pressure (e.g., a blower <NUM>), an outlet muffler <NUM> and one or more transducers <NUM>, such as pressure sensors <NUM> and flow rate sensors <NUM>.

One or more of the air path items may be located within a removable unitary structure which will be referred to as a pneumatic block <NUM>. The pneumatic block <NUM> may be located within the external housing <NUM>. In one form a pneumatic block <NUM> is supported by, or formed as part of, the chassis <NUM>.

The RPT device <NUM> may have an electrical power supply <NUM>, one or more input devices <NUM>, a central controller <NUM>, a therapy device controller <NUM>, a pressure generator <NUM>, one or more protection circuits <NUM>, memory <NUM>, transducers <NUM>, data communication interface <NUM> and one or more output devices <NUM>. Electrical components <NUM> may be mounted on a single Printed Circuit Board Assembly (PCBA) <NUM>. In an alternative form, the RPT device <NUM> may include more than one PCBA <NUM>.

An RPT device may comprise one or more of the following components in an integral unit. In an alternative form, one or more of the following components may be located as respective separate units.

An RPT device in accordance with one form of the present technology may include an air filter <NUM>, or a plurality of air filters <NUM>.

In one form, an inlet air filter <NUM> is located at the beginning of the pneumatic path upstream of a pressure generator <NUM>.

In one form, an outlet air filter <NUM>, for example an antibacterial filter, is located between an outlet of the pneumatic block <NUM> and a patient interface <NUM>.

An RPT device in accordance with one form of the present technology may include a muffler <NUM>, or a plurality of mufflers <NUM>.

In one form of the present technology, an inlet muffler <NUM> is located in the pneumatic path upstream of a pressure generator <NUM>.

In one form of the present technology, an outlet muffler <NUM> is located in the pneumatic path between the pressure generator <NUM> and a patient interface <NUM>.

In one form of the present technology, a pressure generator <NUM> for producing a flow, or a supply, of air at positive pressure is a controllable blower <NUM>. For example the blower <NUM> may include a brushless DC motor <NUM> with one or more impellers. The impellers may be located in a volute. The blower may be capable of delivering a supply of air, for example at a rate of up to about <NUM> litres/minute, at a positive pressure in a range from about <NUM> cmH<NUM>O to about <NUM> cmH<NUM>O, or in other forms up to about <NUM> cmH<NUM>O when delivering respiratory pressure therapy. The blower may be as described in any one of the following patents or patent applications: <CIT>; <CIT>; <CIT>; and <CIT>.

The pressure generator <NUM> is under the control of the therapy device controller <NUM>.

In other forms, a pressure generator <NUM> may be a piston-driven pump, a pressure regulator connected to a high pressure source (e.g. compressed air reservoir), or a bellows.

Transducers may be internal of the RPT device, or external of the RPT device. External transducers may be located for example on or form part of the air circuit, e.g., the patient interface. External transducers may be in the form of noncontact sensors such as a Doppler radar movement sensor that transmit or transfer data to the RPT device.

In one form of the present technology, one or more transducers <NUM> are located upstream and/or downstream of the pressure generator <NUM>. The one or more transducers <NUM> may be constructed and arranged to generate signals representing properties of the flow of air such as a flow rate, a pressure or a temperature at that point in the pneumatic path.

In one form of the present technology, one or more transducers <NUM> may be located proximate to the patient interface <NUM>.

In one form, a signal from a transducer <NUM> may be filtered, such as by low-pass, high-pass or band-pass filtering.

A flow rate sensor <NUM> in accordance with the present technology may be based on a differential pressure transducer, for example, an SDP600 Series differential pressure transducer from SENSIRION.

In one form, a signal generated by the flow rate sensor <NUM> and representing a flow rate is received by the central controller <NUM>.

A pressure sensor <NUM> in accordance with the present technology is located in fluid communication with the pneumatic path. An example of a suitable pressure sensor is a transducer from the HONEYWELL ASDX series. An alternative suitable pressure sensor is a transducer from the NPA Series from GENERAL ELECTRIC.

In one form, a signal generated by the pressure sensor <NUM> is received by the central controller <NUM>.

In one form of the present technology a motor speed transducer <NUM> is used to determine a rotational velocity of the motor <NUM> and/or the blower <NUM>. A motor speed signal from the motor speed transducer <NUM> may be provided to the therapy device controller <NUM>. The motor speed transducer <NUM> may, for example, be a speed sensor, such as a Hall effect sensor.

In one form of the present technology, an anti-spill back valve <NUM> is located between the humidifier <NUM> and the pneumatic block <NUM>. The anti-spill back valve is constructed and arranged to reduce the risk that water will flow upstream from the humidifier <NUM>, for example to the motor <NUM>.

According to one form of the present technology, as shown in <FIG>, the housing <NUM> comprises a closure element in the form of an end cap <NUM>. In this example the end cap <NUM> is configured to seal against the housing <NUM> and can selectively be coupled to a compatible medical device, such as a humidifier <NUM>, as described further below.

In one form as best shown in <FIG>, the end cap <NUM> comprises at least one coupling component <NUM> comprising a gas aperture <NUM> configured to be in fluid communication with the outlet of the pneumatic block <NUM> in use, at least one aperture <NUM>, at least one recess <NUM>, where the at least one aperture <NUM>, recess <NUM> and coupling component <NUM> are configured such that they may facilitate selective connection to a humidifier <NUM>. In other forms of the present technology there are multiple possible embodiments of the outer portion comprising different configurations of one or more of the apertures <NUM>, coupling component <NUM>, and/or recess <NUM> (for example, as illustrated in the exemplary end cap <NUM> shown in <FIG>).

In one form of the present technology, the end cap <NUM> comprises at least one internal channel in fluid communication with at least one aperture <NUM> (also referred to herein as an internal fluid passageway) to divert liquid which has been "spilled" from a selectively connected humidifier <NUM>, or alternatively liquid which has been accidentally spilled onto the RPT device by a user, to the exterior of the housing <NUM>. In further forms end cap <NUM> may comprise a plurality of internal channels to divert liquid from a plurality of apertures, coupling components, or recesses and can be configured in a variety of forms depending on the nature of the selective compatible accessory or medical device. The end cap <NUM> is therefore referred to herein as a liquid diversion assembly.

In one form the end cap <NUM> may be constructed from a plurality of panels, for example proximal panel <NUM>, and distal panel <NUM>. Each panel will be referred to as having an interior surface (e.g. surfaces <NUM>, and <NUM> respectively) and exterior surfaces (e.g. surfaces <NUM>, and <NUM> respectively). These panels <NUM>, <NUM> may be assembled such that during operational orientation the proximal panel <NUM> sits proximal to the electrical components of the medical device <NUM>, and distal panel <NUM> sits distal to the electrical components of the medical device <NUM> (i.e. closer to the humidifier <NUM> when selectively coupled to same). These panels <NUM>, <NUM> may be joined mechanically, thermally or ultrasonically bonded to form the end cap <NUM>. In alternate forms one or more additional panels may be included in the end cap <NUM>. In further alternate forms a single panel may be constructed with a similar internal configuration to that described herein (i.e. the provision of the one or more internal channels), such as through moulding or 3D printing methods.

In one form of the present technology there is provided a proximal panel <NUM> comprising an interior surface <NUM> configured to comprise at least one protrusion forming a guide wall <NUM>. The guide wall <NUM> may project from the interior surface <NUM> of the panel <NUM> at a substantially perpendicular angle, however other angles of protrusion may also be suitable. The proximal panel <NUM> may further comprise at least one recess <NUM>. In use, such recesses <NUM> may receive fastening elements of the humidifier <NUM> (for example, barbed latches configured to be inserted through apertures <NUM> and catch on interior surface <NUM> of the distal panel <NUM>), or components of an electrical connector (for example, a PCB assembly connected to a wiring loom, to which a complementary electrical connector may be coupled). In such examples the at least one protrusion forming a guide wall <NUM> may extend from positions in association with the area defined by the at least one recess <NUM>. In some forms, the at least guide wall <NUM> may comprise one or more superior portions extending along the interior surface <NUM> in a position superior to the at least one recess <NUM>, when the end cap <NUM> is in an operational, or in-use, orientation. In some forms, the at least guide wall <NUM> may comprise one or more lateral portions extending along the interior surface <NUM> in a position to the side of the at least one recess <NUM>. In examples, such as shown in <FIG>, the lateral portions may connect between two superior portions. In some forms, the at least one guide wall <NUM> may substantially surround the at least one recess <NUM>. In some forms the at least one guide wall <NUM> extends beyond the perimeter of the at least one recess <NUM>, for example to connect with the perimeter of the panel <NUM>.

In some forms of the current technology the at least one guide wall <NUM> may be moulded from the same material as the proximal panel <NUM>, however it is also contemplated that the guide wall <NUM> may be formed from a flexible material such as silicone or alternatively constructed from a hydrophobic membrane.

In one form the end cap <NUM> may comprise a distal panel <NUM> distal to the medical device <NUM>. The distal panel <NUM> may comprise a coupling aperture <NUM> configured to receive the coupling component <NUM> - for example shaped to key to the surround of the coupling component <NUM>. The distal panel <NUM> may comprise an interior surface <NUM> configured to comprise at least one protrusion providing a locating feature <NUM>. The at least one locating feature <NUM> may extend at a substantially perpendicular angle to the interior surface <NUM> of the panel <NUM>. The distal panel <NUM> may further comprise at least one aperture <NUM> between interior surface <NUM> and exterior surface <NUM>. The at least one locating feature <NUM> may extend from positions in association with the area defined by the at least one aperture <NUM>. In some forms the locating feature <NUM> may substantially surround the at least one aperture <NUM>.

In examples, distal panel <NUM> may further comprise a perimeter wall <NUM>. The perimeter wall <NUM> may extend at a substantially perpendicular angle to the interior surface <NUM> of the panel <NUM> along at least a portion of the perimeter of the panel <NUM>. In examples the perimeter wall <NUM> may extend along the interior surface <NUM> of the panel <NUM> in a position radially outward of the apertures <NUM>. In examples the perimeter wall <NUM> may extend along the interior surface <NUM> of the panel <NUM> in a position radially outward of the at least one guide wall <NUM>. In examples a portion of the perimeter wall <NUM> may extend along the interior surface <NUM> of the panel <NUM> in a position superior to the at least one guide wall <NUM>. In examples a portion of the perimeter wall <NUM> may extend along the interior surface <NUM> of the panel <NUM> in a position laterally offset from the at least one guide wall <NUM> (i.e. to a side of the guide wall(s) <NUM>).

In operation, liquid may penetrate the RPT device <NUM> in a multitude of ways. In the event of a user accidentally tipping or sloshing liquids over the device, liquid ingress can occur at the perimeter of the end cap <NUM> or, if used without a coupled humidifier, via the one of more apertures <NUM> and recesses <NUM>. When coupled with a humidifier <NUM>, liquid can flow from the reservoir <NUM> (for example, via the non-watertight connectors that cooperate with one or more apertures <NUM>). In the event of liquid penetrating the device either at the perimeter of the end cap <NUM> or from the humidifier <NUM> via the non-watertight connectors, some forms of the present technology provide an end cap <NUM> comprising a plurality of panels <NUM>, <NUM>. The panels <NUM> and <NUM> are configured such that when the proximal <NUM> and distal <NUM> panels are connected into an end cap <NUM>, the interior surfaces <NUM> and <NUM>, and at least one the guide wall <NUM> cooperate to form at least one internal fluid passageway <NUM> within the end cap <NUM>, as illustrated in the cross-sectional view of <FIG>. In examples, the locating feature(s) <NUM> may co-operate with the least one the guide wall <NUM> to provide a watertight seal. In alternative examples, the locating feature(s) <NUM> may function to interact with the guide wall(s) <NUM> to locate the panels <NUM> and <NUM> relative to each other, with sealing occurring between the guide wall(s) <NUM> and the internal surface <NUM> of the distal panel <NUM>.

In the example of <FIG>, the internal fluid passageway <NUM> has a watertight perimeter confining liquid ingressed from the apertures <NUM> and recesses <NUM>, and acts as a channel to diverts any ingressed liquid towards the lower, or inferior, portion of the end cap <NUM>, where there is a gap <NUM> in the watertight perimeter through which the liquid can escape to the outside surface of the RPT device housing <NUM> as a result of gravity, capillary action, or other natural force. The ingressed liquid is thus diverted from the sensitive electrical components of the RPT device <NUM>, described below. The lower surface of one or more of the recesses <NUM> may also be cambered (or more generally angled from a superior position to an inferior position at the interior surface <NUM>), as illustrated in <FIG>, so that any ingressed liquid does not collect in the recess <NUM>, but flows out of it by the action of gravity, and through the internal fluid passageway <NUM> towards the lower portion of the end cap <NUM>.

In some examples, one or more of the surfaces forming the fluid passageway is coated in a hydrophobic material to facilitate faster diversion of liquid to the exterior of the housing <NUM>.

While the exemplary end cap <NUM> of <FIG> has been described with reference to the guide wall <NUM> being provided on the interior surface <NUM> of the proximal panel <NUM>, and the locating feature(s) <NUM> and perimeter wall <NUM> being provided on the interior surface <NUM> of the distal panel <NUM>, it should be appreciated that in alternative examples an inverse arrangement, or a combination thereof, may be utilised to provide the internal fluid passageway(s).

<FIG> shows another example of a closure element in the form of an end cap <NUM> according to an aspect of the present technology. In this example the end cap <NUM> is configured to be selectively coupled to a compatible medical device, such as humidifier <NUM>, to seal against the housing <NUM> of same. As generally described above, the end cap <NUM> is configured to facilitate selective connection to a humidifier <NUM>.

In this example the end cap <NUM> comprises a proximal panel <NUM> having an interior surface <NUM> and an exterior surface <NUM>, and a distal panel <NUM> having an interior surface <NUM> and an exterior surface <NUM>. In this example, the distal panel <NUM> comprises an electrical connector recess <NUM> in exterior surface <NUM> (i.e. projecting from interior surface <NUM>. The proximal panel <NUM> comprises an electrical connector aperture <NUM>, through which the electrical connector recess <NUM> projects, with electrical connector PCB assembly <NUM> mounted to standoffs of the electrical connector recess <NUM> on the exterior side of the proximal panel <NUM>. In use, an electrical connector is inserted into the electrical connector recess <NUM> and interfaces with a corresponding connector coupled to the PCB assembly <NUM>.

In this example, the distal panel <NUM> comprises a plurality of apertures <NUM>. On the interior surface <NUM> of the distal panel <NUM>, a plurality of locating features <NUM> are provided about each aperture <NUM>, extending at a substantially perpendicular angle to the interior surface <NUM> of the panel <NUM>. In examples locating features <NUM> may be provided in superior and/or inferior positions relative to each aperture <NUM>. In examples the length of locating features <NUM> in superior and/or inferior positions, across the interior surface <NUM> (i.e. in a lateral direction), may be less than the width of an associated aperture <NUM>. In examples locating features <NUM> may be provided in one or more lateral positions relative to each aperture <NUM> (i.e. to one or more sides of the aperture <NUM>). In the example shown (see, e.g. <FIG>), the locating features <NUM> are discrete - i.e. not connected to each other, having gaps therebetween.

In examples, distal panel <NUM> may further comprise a perimeter wall <NUM>. The perimeter wall <NUM> may extend at a substantially perpendicular angle to the interior surface <NUM> of the panel <NUM> along at least a portion of the perimeter of the panel <NUM>. In the illustrated example (see, e.g. <FIG>) the perimeter wall <NUM> extends around the perimeter of the panel <NUM>, having a perimeter wall gap <NUM> in a location inferior to the apertures <NUM>.

In this example (see, e.g. <FIG>) the proximal panel <NUM> comprises guide protrusions <NUM> projecting from the interior surface <NUM> of the panel <NUM>. In this example, the guide protrusions <NUM> surround each of the recesses <NUM>. Referring to <FIG>, in this example the guide protrusions <NUM> comprise a raised base <NUM>, and a guide projection <NUM> extending from the raised base <NUM>. In this example, the guide projection <NUM> has a radially outward facing surface and a radially inward facing surface tapering towards each other to meet at a pointed apex - although it should be appreciated that in alternative examples the apex may be rounded, or flat. In this example, a plateau portion is provided between a radially outward edge of the raised base <NUM> and the guide projection <NUM>. In alternative examples, the guide projection <NUM> may extend directly from the interior surface <NUM> (i.e. the guide protrusion <NUM> may not comprise a raised base <NUM>).

Referring to <FIG>, in this example the proximal panel <NUM> comprises a locating wall <NUM> projecting from the interior surface <NUM> of the panel <NUM>. The locating wall <NUM> extends along the interior surface <NUM> in a radially outward position relative to the recesses <NUM>, aligning with the perimeter wall <NUM> of the distal panel <NUM> when formed as the end cap <NUM>. The locating wall <NUM> also comprises a locating wall gap <NUM>, substantially aligned with the perimeter wall gap <NUM> of the of the distal panel <NUM>.

Referring to <FIG> and <FIG>, when the end cap <NUM> is formed by joining of the proximal panel <NUM> and the distal panel <NUM>, an internal fluid passageway <NUM> is formed therebetween. The perimeter wall <NUM> and locating wall <NUM> cooperate to form a seal around the periphery of the internal fluid passageway <NUM>, more particularly extending around the surfaces comprising apertures <NUM> and recesses <NUM> collectively, with the exception of gap <NUM> produced by the locating wall gap <NUM> and the perimeter wall gap <NUM> at an inferior position. In this example, the seal extends around the periphery of the coupling component <NUM> and coupling aperture <NUM>. Liquid entering the internal fluid passageway <NUM> is permitted to flow through to the exterior of the end cap <NUM> via the gap <NUM>. With particular reference to <FIG>, in this example liquid moving downwards towards a recess <NUM>, or flowing from the recess <NUM>, is encouraged by the shaped surfaces of the guide protrusion <NUM> to move towards the interior surface <NUM> and flow down the internal fluid passageway <NUM> towards the gap <NUM>.

A power supply <NUM> may be located internal or external of the external housing <NUM> of the RPT device <NUM>.

In one form of the present technology, power supply <NUM> provides electrical power to the RPT device <NUM> only. In another form of the present technology, power supply <NUM> provides electrical power to both RPT device <NUM> and humidifier <NUM>.

In one form of the present technology, an RPT device <NUM> includes one or more input devices <NUM> in the form of buttons, switches or dials to allow a person to interact with the device. The buttons, switches or dials may be physical devices, or software devices accessible via a touch screen. The buttons, switches or dials may, in one form, be physically connected to the external housing <NUM>, or may, in another form, be in wireless communication with a receiver that is in electrical connection to the central controller <NUM>.

In one form, the input device <NUM> may be constructed and arranged to allow a person to select a value and/or a menu option.

In one form of the present technology, the central controller <NUM> is one or a plurality of processors suitable to control an RPT device <NUM>.

Suitable processors may include an x86 INTEL processor, a processor based on ARM® Cortex®-M processor from ARM Holdings such as an STM32 series microcontroller from ST MICROELECTRONIC. In certain alternative forms of the present technology, a <NUM>-bit RISC CPU, such as an STR9 series microcontroller from ST MICROELECTRONICS or a <NUM>-bit RISC CPU such as a processor from the MSP430 family of microcontrollers, manufactured by TEXAS INSTRUMENTS may also be suitable.

In one form of the present technology, the central controller <NUM> is a dedicated electronic circuit.

In one form, the central controller <NUM> is an application-specific integrated circuit. In another form, the central controller <NUM> comprises discrete electronic components.

The central controller <NUM> may be configured to receive input signal(s) from one or more transducers <NUM>, one or more input devices <NUM>, and the humidifier <NUM>.

The central controller <NUM> may be configured to provide output signal(s) to one or more of an output device <NUM>, a therapy device controller <NUM>, a data communication interface <NUM>, and the humidifier <NUM>.

In some forms of the present technology, the central controller <NUM> is configured to implement the one or more methodologies described herein, such as the one or more algorithms <NUM> expressed as computer programs stored in a non-transitory computer readable storage medium, such as memory <NUM>. In some forms of the present technology, the central controller <NUM> may be integrated with an RPT device <NUM>. However, in some forms of the present technology, some methodologies may be performed by a remotely located device. For example, the remotely located device may determine control settings for a ventilator or detect respiratory related events by analysis of stored data such as from any of the sensors described herein.

The RPT device <NUM> may include a clock <NUM> that is connected to the central controller <NUM>.

In one form of the present technology, therapy device controller <NUM> is a therapy control module <NUM> that forms part of the algorithms <NUM> executed by the central controller <NUM>.

In one form of the present technology, therapy device controller <NUM> is a dedicated motor control integrated circuit. For example, in one form a MC33035 brushless DC motor controller, manufactured by ONSEMI is used.

The one or more protection circuits <NUM> in accordance with the present technology may comprise an electrical protection circuit, a temperature and/or pressure safety circuit.

In accordance with one form of the present technology the RPT device <NUM> includes memory <NUM>, e.g., non-volatile memory. In some forms, memory <NUM> may include battery powered static RAM. In some forms, memory <NUM> may include volatile RAM.

Memory <NUM> may be located on the PCBA <NUM>. Memory <NUM> may be in the form of EEPROM, or NAND flash.

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

In one form of the present technology, the memory <NUM> acts as a non-transitory computer readable storage medium on which is stored computer program instructions expressing the one or more methodologies described herein, such as the one or more algorithms <NUM>.

In one form of the present technology, a data communication interface <NUM> is provided, and is connected to the central controller <NUM>. Data communication interface <NUM> may be connectable to a remote external communication network <NUM> and/or a local external communication network <NUM>. The remote external communication network <NUM> may be connectable to a remote external device <NUM>. The local external communication network <NUM> may be connectable to a local external device <NUM>.

In one form, data communication interface <NUM> is part of the central controller <NUM>. In another form, data communication interface <NUM> is separate from the central controller <NUM>, and may comprise an integrated circuit or a processor.

In one form, remote external communication network <NUM> is the Internet. The data communication interface <NUM> may use wired communication (e.g. via Ethernet, or optical fibre) or a wireless protocol (e.g. CDMA, GSM, LTE) to connect to the Internet.

In one form, local external communication network <NUM> utilises one or more communication standards, such as Bluetooth, or a consumer infrared protocol.

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

The local external device <NUM> may be a personal computer, mobile phone, tablet or remote control.

An output device <NUM> 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.

A display driver <NUM> receives as an input the characters, symbols, or images intended for display on the display <NUM>, and converts them to commands that cause the display <NUM> to display those characters, symbols, or images.

A display <NUM> is configured to visually display characters, symbols, or images in response to commands received from the display driver <NUM>. For example, the display <NUM> may be an eight-segment display, in which case the display driver <NUM> converts each character or symbol, such as the figure "<NUM>", to eight logical signals indicating whether the eight respective segments are to be activated to display a particular character or symbol.

As mentioned above, in some forms of the present technology, the central controller <NUM> may be configured to implement one or more algorithms <NUM> expressed as computer programs stored in a non-transitory computer readable storage medium, such as memory <NUM>. The algorithms <NUM> are generally grouped into groups referred to as modules.

In other forms of the present technology, some portion or all of the algorithms <NUM> may be implemented by a controller of an external device such as the local external device <NUM> or the remote external device <NUM>. In such forms, data representing the input signals and / or intermediate algorithm outputs necessary for the portion of the algorithms <NUM> to be executed at the external device may be communicated to the external device via the local external communication network <NUM> or the remote external communication network <NUM>. In such forms, the portion of the algorithms <NUM> to be executed at the external device may be expressed as computer programs stored in a non-transitory computer readable storage medium accessible to the controller of the external device. Such programs configure the controller of the external device to execute the portion of the algorithms <NUM>.

In such forms, the therapy parameters generated by the external device via the therapy engine module <NUM> (if such forms part of the portion of the algorithms <NUM> executed by the external device) may be communicated to the central controller <NUM> to be passed to the therapy control module <NUM>.

An air circuit <NUM> in accordance with an aspect of the present technology is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components such as RPT device <NUM> and the patient interface <NUM>.

In particular, the air circuit <NUM> may be in fluid connection with the outlet of the pneumatic block <NUM> and the patient interface. The air circuit may be referred to as an air delivery tube. In some cases there may be separate limbs of the circuit for inhalation and exhalation. In other cases a single limb is used.

In some forms, the air circuit <NUM> may comprise one or more heating elements configured to heat air in the air circuit, for example to maintain or raise the temperature of the air. The heating element may be in a form of a heated wire circuit, and may comprise one or more transducers, such as temperature sensors. In one form, the heated wire circuit may be helically wound around the axis of the air circuit <NUM>. The heating element may be in communication with a controller such as a central controller <NUM>. One example of an air circuit <NUM> comprising a heated wire circuit is described in <CIT>.

In one form of the present technology, supplementary gas, e.g. oxygen, <NUM> is delivered to one or more points in the pneumatic path, such as upstream of the pneumatic block <NUM>, to the air circuit <NUM>, and/or to a patient interface.

Ambient: In certain forms of the present technology, the term ambient will be taken to mean (i) external of the treatment system or patient, and (ii) immediately surrounding the treatment system or patient.

For example, ambient humidity with respect to a humidifier may be the humidity of air immediately surrounding the humidifier, e.g. the humidity in the room where a patient is sleeping. Such ambient humidity may be different to the humidity outside the room where a patient is sleeping.

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

In certain forms, ambient (e.g., acoustic) noise may be considered to be the background noise level in the room where a patient is located, other than for example, noise generated by an RPT device or emanating from a mask or patient interface. Ambient noise may be generated by sources outside the room.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in which the treatment pressure is automatically adjustable, e.g. from breath to breath, between minimum and maximum limits, depending on the presence or absence of indications of SDB events.

Continuous Positive Airway Pressure (CPAP) therapy: Respiratory pressure therapy in which the treatment pressure is approximately constant through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for example, being increased in response to detection of indications of partial upper airway obstruction, and decreased in the absence of indications of partial upper airway obstruction.

Humidifier: The word humidifier will be taken to mean a humidifying apparatus constructed and arranged, or configured with a physical structure to be capable of providing a therapeutically beneficial amount of water (H<NUM>O) vapour to a flow of air to ameliorate a medical respiratory condition of a patient.

Leak: The word leak will be taken to be an unintended flow of air or liquid.

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

Pressure: Force per unit area. Pressure may be expressed in a range of units, including cmH<NUM>O, g-f/cm<NUM> and hectopascal. <NUM> cmH<NUM>O is equal to <NUM>-f/cm<NUM> and is approximately <NUM> hectopascal (<NUM> hectopascal = <NUM> Pa = <NUM> N/m<NUM> = <NUM> millibar ~ <NUM> atm). In this specification, unless otherwise stated, pressure is given in units of cmH<NUM>O.

The pressure in the patient interface is given the symbol Pm, while the treatment pressure, which represents a target value to be achieved by the interface pressure Pm at the current instant of time, is given the symbol Pt.

Respiratory Pressure Therapy (RPT): The application of a supply of air to an entrance to the airways at a treatment pressure that is typically positive with respect to atmosphere.

Ventilator: A mechanical device that provides pressure support to a patient to perform some or all of the work of breathing.

Silicone or Silicone Elastomer: A synthetic rubber. In this specification, a reference to silicone is a reference to liquid silicone rubber (LSR) or a compression moulded silicone rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless otherwise specified to the contrary, an exemplary form of LSR has a Shore A (or Type A) indentation hardness in the range of about <NUM> to about <NUM> as measured using ASTM D2240.

Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.

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

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

Hardness: The ability of a material per se to resist deformation (e.g. described by a Young's Modulus, or an indentation hardness scale measured on a standardised sample size).

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

Floppy structure or component: A structure or component that will change shape, e.g. bend, when caused to support its own weight, within a relatively short period of time such as <NUM> second.

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

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

Products in accordance with the present technology may comprise one or more three-dimensional mechanical structures, for example a mask cushion or an impeller. The three-dimensional structures may be bounded by two-dimensional surfaces. These surfaces may be distinguished using a label to describe an associated surface orientation, location, function, or some other characteristic. For example a structure may comprise one or more of an anterior surface, a posterior surface, an interior surface and an exterior surface. In another example, a seal-forming structure may comprise a face-contacting (e.g. outer) surface, and a separate non-face-contacting (e.g. underside or inner) surface. In another example, a structure may comprise a first surface and a second surface.

To facilitate describing the shape of the three-dimensional structures and the surfaces, we first consider a cross-section through a surface of the structure at a point, p. The outward normal vector at p points away from the surface. In some examples we describe the surface from the point of view of an imaginary small person standing upright on the surface.

The curvature of a plane curve at p may be described as having a sign (e.g. positive, negative) and a magnitude (e.g. <NUM>/radius of a circle that just touches the curve at p).

Positive curvature: If the curve at p turns towards the outward normal, the curvature at that point will be taken to be positive (if the imaginary small person leaves the point p they must walk uphill). Such curves are often referred to as concave.

Zero curvature: If the curve at p is a straight line, the curvature will be taken to be zero (if the imaginary small person leaves the point p, they can walk on a level, neither up nor down).

Negative curvature: If the curve at p turns away from the outward normal, the curvature in that direction at that point will be taken to be negative (if the imaginary small person leaves the point p they must walk downhill).

A description of the shape at a given point on a two-dimensional surface in accordance with the present technology may include multiple normal cross-sections. The multiple cross-sections may cut the surface in a plane that includes the outward normal (a "normal plane"), and each cross-section may be taken in a different direction. Each cross-section results in a plane curve with a corresponding curvature. The different curvatures at that point may have the same sign, or a different sign. Each of the curvatures at that point has a magnitude, e.g. relatively small.

Principal curvatures and directions: The directions of the normal planes where the curvature of the curve takes its maximum and minimum values are called the principal directions.

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

Saddle region: A region where at each point, the principal curvatures have opposite signs, that is, one is positive, and the other is negative (depending on the direction to which the imaginary person turns, they may walk uphill or downhill).

Dome region: A region where at each point the principal curvatures have the same sign, e.g. both positive (a "concave dome") or both negative (a "convex dome").

Cylindrical region: A region where one principal curvature is zero (or, for example, zero within manufacturing tolerances) and the other principal curvature is non-zero.

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

Edge of a surface: A boundary or limit of a surface or region.

Path: In certain forms of the present technology, 'path' will be taken to mean a path in the mathematical - topological sense, e.g. a continuous space curve from f(<NUM>) to f(<NUM>) on a surface. In certain forms of the present technology, a 'path' may be described as a route or course, including e.g. a set of points on a surface. (The path for the imaginary person is where they walk on the surface, and is analogous to a garden path).

Path length: In certain forms of the present technology, 'path length' will be taken to mean the distance along the surface from f(<NUM>) to f(<NUM>), that is, the distance along the path on the surface. There may be more than one path between two points on a surface and such paths may have different path lengths. (The path length for the imaginary person would be the distance they have to walk on the surface along the path).

Straight-line distance: The straight-line distance is the distance between two points on a surface, but without regard to the surface. On planar regions, there would be a path on the surface having the same path length as the straight-line distance between two points on the surface. On non-planar surfaces, there may be no paths having the same path length as the straight-line distance between two points. (For the imaginary person, the straight-line distance would correspond to the distance 'as the crow flies'.

A surface may have a one-dimensional hole, e.g. a hole bounded by a plane curve or by a space curve. Thin structures (e.g. a membrane) with a hole, may be described as having a one-dimensional hole.

A structure may have a two-dimensional hole, e.g. a hole bounded by a surface. For example, an inflatable tyre has a two dimensional hole bounded by the interior surface of the tyre. In another example, a bladder with a cavity for air or gel could have a two-dimensional hole. In a yet another example, a conduit may comprise a one-dimension hole (e.g. at its entrance or at its exit), and a two-dimension hole bounded by the inside surface of the conduit.

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.

Although the technology herein has been described with reference to particular examples, it is to be understood that these examples are merely illustrative of the principles and applications of the technology. In some instances, the terminology and symbols may imply specific details that are not required to practice the technology. For example, although the terms "first" and "second" may be used, unless otherwise specified, they are not intended to indicate any order but may be utilised to distinguish between distinct elements. Furthermore, although process steps in the methodologies may be described or illustrated in an order, such an ordering is not required. Those skilled in the art will recognize that such ordering may be modified and/or aspects thereof may be conducted concurrently or even synchronously.

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

Claim 1:
A liquid diversion assembly for a medical device that includes a housing, (<NUM>) the liquid diversion assembly comprising:
an end cap (<NUM>) in association with the housing, the end cap comprising:
a proximal panel (<NUM>) proximal to the medical device in use,
comprising a first interior surface a (<NUM>) and a first exterior surface; (<NUM>)
a distal panel (<NUM>) distal to the medical device in use, comprising a second interior surface a (<NUM>) and a second exterior surface; (<NUM>)
at least one wall (<NUM>) extending between the first interior surface and the second interior surface;
at least one aperture (<NUM>) for selective coupling with a compatible accessory, wherein the at least one aperture is between the second exterior surface and the second interior surface of the distal panel,
characterized in that
the end cap comprises at least one internal fluid passageway in fluid communication with the at least one aperture to divert liquid to an exterior of the housing, wherein the internal fluid passageway is at least in part defined by the at least one wall, the first interior surface, and the second interior surface.