Patent Description:
The present technology relates to treatment of respiratory disorders, and to procedures to prevent respiratory disorders. In particular, the present technology relates to medical devices, and their use for treating respiratory disorders and for preventing respiratory disorders. More particularly, the present technology relates to a nasal mask system used for treatment, e.g., of Sleep Disordered Breathing (SDB) with Continuous Positive Airway Pressure (CPAP) or Non-Invasive Positive Pressure Ventilation (NIPPV).

The airways consist of a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the air into the venous blood and carbon dioxide to move out. The trachea divides into right and left main bronchi, which further divide eventually into terminal bronchioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further divisions of the airways lead to the respiratory bronchioles, and eventually to the alveoli. The alveolated region of the lung is where the gas exchange takes place, and is referred to as the respiratory zone. See West, Respiratory Physiology- the essentials.

Obstructive Sleep Apnoea (OSA), a form of Sleep Disordered Breathing (SDB), is characterized by occlusion 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 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 a disorder of a patient's respiratory controller 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 disruption, increased sympathetic activity, and increased afterload. See <CIT>).

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: dyspnoea 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, dyspnoea 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: dyspnoea on exertion, peripheral oedema, orthopnoea, repeated chest infections, morning headaches, fatigue, poor sleep quality and loss of appetite.

Otherwise healthy individuals may take advantage of systems and devices to prevent respiratory disorders from arising.

One known product used for treating sleep disordered breathing is the S9 Sleep Therapy System, manufactured by ResMed.

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 forward and away from the posterior oropharyngeal wall.

Non-invasive ventilation (NIV) has been used to treat OHS, COPD, NMD and Chest Wall disorders.

The application of a supply of air at positive pressure to the entrance of the airways of a patient, e.g., while a patient sleeps, is facilitated by the use of a patient interface, such as a nasal mask, full-face mask or nasal pillows.

Known patient interface devices suffer from being one or more of obtrusive, aesthetically undesirable, poorly fitting, difficult to use and uncomfortable, especially when worn for long periods of time or when a patient is unfamiliar with a system.

Patient interfaces typically include a seal-forming portion.

A range of patient interface seal-forming portion technologies are disclosed in the following patent applications, assigned to <CIT>; <CIT>; <CIT>.

<CIT> discloses a nasal mask for supplying gas under pressure to an airway of a human including: a flexible manifold shell, being made of a flexible material, the manifold including means for connection to a gas delivery pipe.

A seal-forming portion of a patient interface used for positive air pressure therapy is subject to the corresponding force of the air pressure to disrupt a seal. Thus a variety of techniques have been used to position the seal-forming portion, and to maintain it in sealing relation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US Patent publication <CIT>.

Another technique is the use of one or more straps and stabilising harnesses.

Some forms of patient interface systems may include a vent to allow the washout of exhaled carbon dioxide.

ResMed Limited has developed a number of mask vent technologies. See <CIT>; <CIT>; <CIT>; US Patent Application; <CIT>; <CIT>.

The current invention is defined in the appended independent claim <NUM>. Preferred embodiments are matter of the dependent claims. Claim <NUM> defines a CPAP system comprising a patient interface of the invention.

The present technology is directed towards providing medical devices used in the diagnosis, 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 diagnosis, treatment or prevention of a respiratory disorder.

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

One aspect of the present technology is a patient interface that is one or more of comfortable, effective, simple to use, unobtrusive and with a wide fit range.

An aspect of one form of the present technology is a patient interface that avoids a jetting effect of nasal pillows or prongs, and/or a feeling of discomfort from locating a portion of a mask within a nasal cavity of a patient.

An aspect of one form of the present technology is a nasal mask that is easy to put on, and may avoid a need for headgear straps to interfere with, or cross the ears in use, and may avoid interfering or crossing the ears while putting on or removing.

Another aspect of one form of the present technology is a method of putting on or removing a mask.

In one form of the present technology, a small, unobtrusive nasal mask is provided.

In one form of the present technology, a nasal mask is provided that does not form a seal on a lower lip, or a chin of a patient.

In one form of the present technology, a patient interface is provided that does not exert a rearward force on the mandible, e.g. the patient interface does not push on the mandible from the anterior towards the posterior.

In one form of the present technology, a patient interface is provided that does not comprise a rigid shell or rigid frame.

In one form of the present technology, a patient interface is provided that comprises a plenum chamber constructed from a flexible or semi-rigid material, for example a flexible rubber of a suitable thickness (e.g. silicone with a type A hardness in the range of about <NUM> to about <NUM>, and about <NUM> to about <NUM> thick).

In one form of the technology, a nasal mask is provided that does not require engagement or disengagement of a clip to don or remove the mask.

An aspect of one form of the present technology is a patient interface comprising a seal-forming portion having a first sealing region that is constructed to have little nor no resistance to compression, and a second sealing region that is constructed to substantially resist a compressive force (e.g. as a result of headgear tension). In an example in use, the first sealing region is arranged to overlay a portion of the cartilaginous framework of the nose, and the second sealing region is arranged to overlay a portion of a bone region the face. In an example, the bone region of the face is a region adjacent the ala, and optionally adjacent to the alar crest point.

According to one form of the present technology, a patient interface is provided that comprises: (i) a seal-forming portion that in use overlays at least part of a top lip region of a patient's face, and a portion of the cartilaginous framework of the nose; and (ii) a seal positioning and stabilising structure that may be donned and removed without interfering with the ears of the patient.

Another aspect of one form of the present technology is a patient interface having a seal-forming portion associated with a two point connection with a seal positioning and stabilising structure. In an example, the patient interface does not comprise a forehead support. In an additional or alternative example, the seal positioning and stabilising structure comprises a non-rigid or flexing connection element.

Another aspect of one form of the present technology is a patient interface that is moulded or otherwise constructed with a clearly defined perimeter shape which is intended to match that of an intended wearer in use.

Another aspect of one form of the present technology is a patient interface that is constructed and arranged so that while forming a seal on at least part of the cartilaginous framework of the nose, it avoids or reduces a tendency to restrict nasal air flow therethrough.

According to one form of the present technology, a patient interface is provided that comprises a first superior sealing portion that in use overlays a portion of the cartilaginous framework of the nose, and a second inferior sealing portion that in use overlays a portion of the upper lip and wherein in use, a relatively larger portion of a headgear sealing force is directed towards the portion of the upper lip and the underlying maxilla, teeth or gum than is directed towards the cartilaginous framework of the nose.

Another aspect of one form of the present technology is a patient interface that is constructed and arranged to avoid or reduce a tendency to put unnecessary pressure on the nasal septum.

According to one form of the present technology, a patient interface is provided that in use forms a seal on a portion of an upper lip of a patient, and which comprises a plenum chamber having a wall and wherein a first portion of the wall that is constructed to be located adjacent the septum in use has a relatively less stiff spring constant that portions of the wall that are adjacent to said first portion.

Another aspect of one form of the present technology is a patient interface that while forming a seal on a portion of the cartilaginous framework of the nose, provides an effective or improved seal on the region of the nose near a junction between the greater alar cartilage and the lateral cartilage.

According to one form of the present technology, a patient interface is provided that comprises a sealing flange that defines a generally T-shaped, or three lobed orifice. In an example, the sealing flange includes a membrane and a sealing flap that protrudes from the edge of the membrane along its inner perimeter in each side of nose region. The edge of the membrane along its inner perimeter along with the edge of each sealing flap along its inner perimeter cooperate to define an orifice into the plenum chamber. In an example, such orifice includes a general T-shape, or three lobed orifice, including an upper orifice portion (along vertical axis v as viewed in <FIG>) and a lower orifice portion (along horizontal axis h as viewed in <FIG>) that extends generally transverse to the upper orifice portion.

According to one form of the present technology, an inner edge of a sealing flange is spring biased towards the face of a wearer in use, e.g. with respect to a middle portion of the sealing flange.

Another aspect of one form of the present technology is a nasal mask that is constructed and arrange to pivot or rotate about a top lip region upon adjustment of a headgear tension.

Another aspect of one form of the present technology is a method of manufacturing a patient interface.

Another aspect of one form of the present technology is a device for preventing, treating or ameliorating one or more of OSA, CSA, OHS, COPD, NMD and chest-wall disorders.

Another aspect of the present technology is a mask system that can accommodate a wide range of different facial shapes including faces with high and low nose bridge regions, and narrow and wide noses. Another aspect of the present technology is a mask system with a wide fit range.

Another aspect of one form of the present technology is a mask system that is small and unobtrusive, and yet is stable on the face while a patient is sleeping.

One aspect of the present technology is a mask that is constructed and arranged to seal at its upper extent on a region of the nose that is generally above or superior to the pronasale, or tip of the nose.

One aspect of one form of the present technology is a mask that is constructed and arranged to seal at its upper extent af locations that are generally below or inferior to the nasal bones.

In one form of the present technology, a mask is provided that is constructed and arranged to have a seal forming portion that overlays a portion of the upper or superior lip, and that overlays a portion of the cartilaginous framework of the nose, e.g., without overlaying the nasal bones.

In one form of the present technology a mask is provided that is constructed and arranged to have a first seal forming portion that overlays a portion of the upper or superior lip, and a second seal-forming portion that overlays of the cartilaginous framework of the nose, e.g., without overlaying the nasal bones.

In one form of the present technology a mask is provided that is constructed and arranged to have a first seal forming portion that is substantially in compression, or subject to bending forces in use, and a second seal-forming portion that is substantially in tension in use.

In one form of the present technology a mask is provided that is constructed and arranged to have a first seal forming portion that is relatively stiff before use, and a second seal-forming portion that is relatively floppy before use.

Another aspect of one form of the present technology is a mask system with an improved sealing cuff. In an example, the mask system includes a facial flap comprising a relatively thin member formed of a flexible, e.g., and at least semi-resilient, material. In an example, the mask system further comprises, in at least some regions, a back-up band.

Another aspect of the present technology is a mask that is formed, moulded or otherwise constructed with a clearly defined perimeter shape which is intended to match that of an intended wearer.

A further aspect of the present technology is a cushion for a mask that seals at its upper extent in a region of the nose that is generally superior to or above the pronasale or tip of the nose, and extends across the alar or flares of the patient's nose.

A further aspect of the present technology is a cushion for a mask that seals at its upper extent in a region of the nose that is generally superior to or above the pronasale or tip of the nose, and extends across the alar or flares of the patient's nose, e.g., not extending over or across the nasal bones of the patient's nose.

One aspect of one form of the present technology is a cushion for a mask that seals at its upper extent in a region of the nose that is generally close to the junction between bone and cartilage on a range of people with larger noses, and which avoids impinging on the sight of people with smaller noses.

In one form of the present technology, a mask system is provided that does not require a rigid frame or skeleton, and which seals at its upper extent in a region of the nose that is generally above or superior to the pronasale, or tip of the nose.

One aspect of the present technology is a cushion for a mask that includes a sealing membrane and a backup band or undercushion, in at least some regions.

Another aspect of the present technology is a cushion for a nasal mask that includes an undercushion or backup band in the region of the top lip.

Another aspect of one form of the present technology is a cushion for a nasal mask that includes an undercushion or backup band in the region of the top lip, and no undercushion or backup band in the sides of the nose or ridge of the nose regions to avoid relatively high sealing forces on the sides of the nose or ridge of the nose regions as these relatively high sealing forces may cause occlusion of the nasal airway.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a sealing region, a side wall region and an attachment region, wherein the sealing region is, adapted to form a seal with a patient, the side wall region connects the sealing region and attachment region, and the attachment region is adapted to connect or otherwise attach to an air delivery system.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a sealing region and an attachment region, wherein the attachment region comprises a decoupling element.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a sealing region and an attachment region, wherein the attachment region comprises a decoupling element, the decoupling element comprising a relatively thinner wall section. For example, the relatively thinner wall section may be <NUM>-<NUM>% thinner.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion comprising headgear connectors integrally formed with a side wall, e.g., wherein the side wall is constructed of a flexible elastomer or rubber.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion comprising headgear connectors, the headgear connectors constructed and arranged to position a portion of a sealing region superior to or above the pronasale or tip of the patient's nose.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a nose ridge region, the nose ridge region having a dip or curvature, e.g. a local saddle region, adapted to conform to, or be complementary to the nose ridge of the patient.

A further aspect of the present technology includes a cushion for a nasal mask, the cushion having a nose ridge region, the nose ridge region having a relatively longer membrane length when compared to other regions of the cushion, the relatively longer membrane length adapted to engage a greater fit range of patient's nose ridge heights.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a sides of the nose region, the sides of the nose region having a raised portion, the raised portion having a greater height when compared to the nose ridge region, the raised portion adapted to engage with the sides of the patient's nose and ensure engagement with tall nose ridges as well as flat nose ridges.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a corners of the nose region, generally corresponding to the region of the face between and including the subalare and the alar crest, the corners of the nose region having the greatest height when compared to all other regions of the cushion, wherein the corners of the nose region anchors the cushion in position. The height of the corners of the nose region may be arranged to ensure seal in the corners of the nose, as this is a particularly difficult area of the face to seal on.

Another aspect of the present technology includes a cushion for a nasal mask, the cushion having a top lip region, the top lip region configured to conform to the curvature of a patient's top lip region. The top lip region may be generally rounded, extending from a trough or dip and continuing up to the sides of the nose region. The membrane at the top lip region may stretch across a patient's top lip to ensure a seal with the patient's top lip.

Another aspect of the present technology relates to a nasal mask system including a cushion assembly including a sealing region that provides a single orifice adapted to surround both nares of the patient's nose and a headgear assembly including a pair of side straps and a rear strap. The side straps are adapted to extend along sides of the patient's face between the patient's eyes and ears and engage respective headgear connectors provided to the cushion assembly to provide a two-point connection with the cushion assembly. The rear strap extends between the side straps and is adapted to engage along the back or posterior of the patient's head along, below or inferior to the occipital bone.

Another aspect of the present technology relates to a nasal mask system including a cushion assembly including a sealing region having a nose ridge region, sides of nose region, corners of nose region, and a top lip region adapted to seal around both nares of the patient's nose. The nose ridge region is adapted to be' positioned and seal along a nasal cartilage region which is above or superior to the pronasale and below or inferior to a nasal bone region of the patient's nasal bridge. In one form, the sealing region includes a membrane seal that extends around an entire perimeter of the sealing region and an undercushion that is only provided in the top lip and corners of nose regions.

Another aspect of the present technology relates to a nasal mask system including a cushion assembly including a sealing region adapted to seal around both nares of the patient's nose, an attachment region adapted to receive an elbow assembly, and a side wall region extending between the sealing region and the attachment region. The sealing region has a nose ridge region, sides of nose region, corners of nose region, and a top lip region. The side wall region includes an area adjacent the top lip region of the sealing region that includes a thickness that is less than corresponding thicknesses adjacent the nose ridge, sides of nose, and corners of nose regions of the sealing region.

Another aspect of the present technology relates to a nasal mask system including a cushion assembly including a sealing region having a nose ridge region, sides of nose region, corners of nose region, and a top lip region adapted to seal around both nares of the patient's nose. The sides of nose region includes a portion adapted to be positioned and seal along a region adjacent the junction between the nasal greater alar cartilage and the lateral nasal cartilage of the patient's nose.

Another aspect of the present technology relates to a patient interface for applying a supply of air at positive pressure to the entrance of a patient's airways. The patient interface includes a nasal mask and a positioning and stabilising structure. The nasal mask has a seal forming portion constructed and arranged to form a seal on a portion of an upper lip of a patient, and to form a seal on a portion of a cartilaginous framework of the patient's nose. The nasal mask further has a plenum chamber that receives in use a portion of the patient's nose including the pronasale. The positioning and stabilising structure includes a pair of side straps that provide a two-point connection to the nasal mask and being constructed and arranged to be donned or removed without the side straps passing inferior to the patient's ears.

Another aspect of the present technology relates to a method for fitting a patient interface to a patient. The method includes positioning a sealing region of the patient interface with respect the patient's nose such that the sealing region surrounds both nares and engaging headgear straps of the patient interface with the patient's head without passing straps inferior to the patient's ears.

Another aspect of the present technology relates to a nasal mask for delivery of a supply of air to the entrance of a patient's airways. The nasal mask includes a superior sealing portion and an inferior sealing portion. The superior sealing portion is constructed and arranged to be located on a portion of the cartilaginous framework of the nose, and to form a seal therewith without exerting a sealing force that would restrict a flow of air through the nasal cavity. The inferior sealing portion is constructed and arranged to be located in part on a portion of an upper lip of a patient and to direct a sealing force to a portion of a maxilla bone of the patient.

Another aspect of the present technology relates to a nasal mask defining a breathing chamber for delivery of a supply of gas at positive pressure to the airways of a patient. The nasal mask includes a vent ad a cushion. The vent is adapted to exhaust breathable gas and is adapted to be sufficiently rigid to avoid collapse. The cushion includes a sealing cuff and headgear connectors. The sealing cuff comprises a membrane seal and an undercushion. The membrane seal extends about a perimeter of the cushion including a nose ridge region of the cushion and a side of the nose region of the cushion, and the undercushion is located in a top lip region of the cushion and does not extend to the nose ridge region of the cushion or the side of the nose region of the cushion. The headgear connectors are formed with a side wall of the cushion.

Another aspect of the present technology relates to a patient interface for applying a supply of air at positive pressure to the entrance of a patient's airways. The patient interface includes a nasal mask and a positioning and stabilising structure. The nasal mask has a seal forming portion constructed and arranged to form a seal on a portion of an upper lip of a patient, and to form a seal on a portion of a cartilaginous framework of the patient's nose. The nasal mask further has a plenum chamber that receives in use a portion of the patient's nose including the pronasale. The positioning and stabilising structure provides a sealing vector oriented at an angle with respect to a Frankfort horizontal direction. The positioning and stabilising structure includes a two-point connection to the nasal mask.

Another aspect of the present technology relates to a patient interface for applying a supply of air at positive pressure to the entrance of a patient's airways. The patient interface includes a nasal mask and a positioning and stabilising structure. The nasal mask has a seal forming portion constructed and arranged to form a seal on a portion of an upper lip of a patient, and to form a seal on a portion of a cartilaginous framework of the patient's nose. The nasal mask further has a plenum chamber that receives in use a portion of the patient's nose including the pronasale. The positioning and stabilising structure provides a sealing vector oriented at an angle with respect to a Frankfort horizontal direction. The nasal mask does not include a forehead support.

Another aspect of the present technology relates to a patient interface for applying a supply of air at positive pressure to the entrance of a patient's airways. The patient interface includes a nasal mask and a positioning and stabilising structure. The nasal mask has a seal forming portion constructed and arranged to form a seal on a portion of an upper lip of a patient, and to form a seal on a portion of a cartilaginous framework of the patient's nose. The nasal mask further has a plenum chamber that receives in use a portion of the patient's nose including the pronasale. The positioning and stabilising structure provides a sealing vector oriented at an angle with respect to a Frankfort horizontal direction. The positioning and stabilising structure includes a pair of side straps adapted to extend towards and over a crown of the patient's head.

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

The term "air" will be taken to include breathable gases, for example air with supplemental oxygen. Hence a supply of air may correspond to a supply of gas including air and supplemental oxygen.

Examples of the technology are directed towards a nasal mask system that is easy and quick to fit (e.g., with little or no adjustment), enable reduced strap tension, is manufacturable in high volumes, provides high consumer appeal, provides comfort and seal, provides reliable quality, unobtrusive, and/or fits a large majority of the population.

One or more examples may include exemplary metrics, e.g., dimensions, angles, percentages, etc. Although specific metrics and ranges therefore may be provided, it is to be understood that these metrics and ranges are merely exemplary and other metrics and ranges are possible depending on application. For example, metrics/ranges that vary from those provided +/- <NUM>-<NUM>% may be suitable for particular applications.

In one form, the present technology comprises apparatus for treating a respiratory disorder. In an example, the apparatus comprises a flow generator or blower for supplying pressurised respiratory gas, such as air, to the patient <NUM> via an air delivery tube leading to a patient interface <NUM> (e.g., see Fig. la). In one form, the apparatus is a CPAP system, in other forms the apparatus is a ventilator.

In one form, the present technology comprises a method for treating a respiratory disorder comprising the step of applying positive pressure to the entrance of the airways of a patient <NUM> (e.g., see Fig. la).

In one form, the present technology comprises a method of treating Obstructive Sleep Apnea in a patient by applying nasal continuous positive airway pressure to the patient.

A patient interface <NUM> in accordance with one aspect of the present technology comprises the following functional aspects: a seal-forming structure <NUM>, a plenum chamber <NUM>, a positioning and stabilising structure <NUM> and a connection port <NUM> for connection to an air circuit <NUM> (e.g., see <FIG>). 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 <NUM> is arranged to surround an entrance to the airways of the patient so as to facilitate the supply of air at positive pressure to the airways.

In an example, the plenum chamber <NUM> and the seal forming structure <NUM> are moulded in one piece. In another example they are formed as two or more separate components.

A patient interface <NUM> in accordance with one form of the present technology is nasal mask system <NUM>. As shown in <FIG>, nasal mask system <NUM> in accordance with the present technology may comprise a headgear assembly <NUM>, an elbow assembly <NUM>, an air delivery assembly <NUM> and a cushion assembly or cushion <NUM>. <FIG> show various views of the cushion assembly <NUM>, and <FIG> show various views of the elbow assembly <NUM>.

A plenum chamber <NUM> in accordance with one form of the present technology is cushion assembly <NUM>. Cushion assembly <NUM> may be adapted to sealingly engage with a patient's airway, including a patient's nose. As shown in <FIG>, cushion assembly <NUM> may receive breathable gas from air delivery assembly <NUM> and/or elbow assembly <NUM>, and be supported in position by headgear assembly <NUM>.

Cushion assembly <NUM> may comprise a sealing region or sealing cuff <NUM>, two headgear connectors <NUM>, a side wall or side wall region <NUM> and an attachment region <NUM>. In an example, cushion assembly <NUM> may be formed from a flexible elastomer or rubber.

<FIG>, <FIG>, and <NUM>-<NUM>-<NUM> to <FIG> show various views of a cushion assembly <NUM> according to another example of the present technology, which is similar to the cushion assembly <NUM>. As described below, the cushion assembly <NUM> includes a thinner wall section adjacent a top lip region of the sealing region of the cushion assembly (e.g., to avoid excessive pressure on the patient's columella and septum). Also, each side of the nose region of the sealing region includes a wing or sealing flap adapted to form a seal on the region adjacent the junction between the nasal greater alar cartilage and the lateral nasal cartilage of the patient's nose.

In the illustrated example of <FIG>, D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), and D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>). Although specific dimensions are provided, it is to be understood that these dimensions are merely exemplary and other dimensions are possible depending on application. For example, the exemplary dimensions may vary by +/-<NUM>-<NUM>% or more or less depending on application.

In one form of the present technology, a seal-forming structure <NUM> provides a sealing-forming surface, and may additionally provide a cushioning function.

In an example, a seal-forming structure <NUM> in accordance with the present technology is constructed from a soft, flexible, resilient material such as silicone.

In one form, the seal-forming structure <NUM> comprises a sealing flange <NUM> and a support flange <NUM>. In one form of the present technology, sealing flange <NUM> includes membrane <NUM> of the sealing region <NUM> and support flange <NUM> includes undercushion or backup band <NUM> of the sealing region <NUM> (e.g., see <FIG>). In an example, the sealing flange <NUM> comprises a relatively thin member with a thickness of less than about <NUM>, for example about <NUM> to about <NUM> that extends around the perimeter <NUM> of the plenum chamber <NUM>. In an example, the support flange <NUM> is relatively thicker than the sealing flange <NUM>. The support flange <NUM> is disposed between the sealing flange <NUM> and the marginal edge <NUM> of the plenum chamber <NUM>, and extends at least part of the way around the perimeter <NUM> of the plenum chamber <NUM>. The support flange <NUM> is a spring-like element and functions to support the sealing flange <NUM> from buckling in use. In use the sealing flange <NUM> can readily respond to system pressure in the plenum chamber <NUM> acting on its underside to urge it into tight sealing engagement with the face.

In one form of the present technology, seal-forming structure <NUM> comprises a superior sealing portion <NUM> and an inferior sealing portion <NUM> (e.g., see <FIG> and <FIG>). The superior sealing portion <NUM> and the inferior sealing portion <NUM> are, e.g., located adjacent one another, and one region may blend into the other.

Superior sealing portion <NUM> is constructed and arranged to form a seal on a portion of the cartilaginous framework of the nose. In an example, superior sealing portion <NUM> is constructed from a relatively thin material, e.g. a flap, flange or membrane of material e.g. a thermoplastic elastomer, or a silicone rubber, and further, e.g., one that readily bends or folds in response to light finger pressure when not in use. Depending on the shape of the nose with which it is being used, a relatively narrow width of superior sealing portion <NUM> may engage with nose ridge to form a seal. A relatively wider portion of superior sealing portion <NUM> may engage with the skin adjacent lateral nasal cartilage to form a seal. See, e.g., <FIG>.

The superior sealing portion <NUM> is not designed to overlay the whole of the nose.

In an example, the superior sealing portion <NUM> is constructed and arranged, e.g. by being thin and flexible, to be adaptable to different heights of nose ridge. In this way, the range of faces that will be able to get a good seal is increased.

Furthermore, for a given face and nose, the flexibility of the superior sealing portion <NUM> means that a seal may be maintained should the plenum chamber <NUM> may be moved, e.g. in response to movement of the air circuit <NUM>.

While the superior sealing portion is constructed so that it does not overlay the nasal bones in use, certain portions of the superior sealing portion may overlay some part of the nasal bones on some faces, depending on exactly how the patient interface is used and the size and shape of the particular face.

In an alternative form, the superior sealing portion is constructed and arranged to form a seal on the nasal bones in use.

Inferior sealing portion <NUM> is constructed and arranged to form seal on a portion of the upper lip of a patient, and to direct at least part of a sealing force to the maxilla bone of the patient. In use, part of the inferior sealing portion <NUM> is located close to the subalare and the alar crest point.

In one form, inferior sealing portion is configured to avoid excessive pressure on the upper teeth or gums. In an example, the inferior sealing portion does not extend along bone (e.g., frontal process of maxilla) superiorly to the alar crest point, however it should be appreciated that in other examples it might.

Inferior sealing portion <NUM> may be constructed from a single, relatively thicker flap, rim or flange of material, e.g. a silicone rubber, or thermoplastic elastomer, e.g. with a thickness of about <NUM> to <NUM>. In one form, inferior sealing portion <NUM> may be constructed from a dual flap, rim or flange, for example one being relatively thin and the other being relatively thick. Alternatively, inferior sealing portion <NUM> may be constructed from a gel-filled bladder.

<FIG> show various views of a cushion assembly <NUM> according to another example of the present technology. In this example, the cushion assembly includes a general "W" shape in the top lip region, i.e., general "W" shape along the outer (inferior) edge <NUM>(o) of the membrane <NUM> in the top lip region as best shown in <FIG>.

<FIG> show various views of a cushion assembly <NUM> according to another example of the present technology. This example shows a cushion assembly with a general "W" shape in the top lip region. In contrast to the example of <FIG>, the cushion example of <FIG> includes general "W" shape along both the inner (superior) edge <NUM>(i) of the membrane <NUM> and the outer (inferior) edge <NUM>(o) of the membrane in the top lip region as best shown in <FIG>.

In one form, the "W" portion of the top lip region is constructed and arranged so that a middle portion of the "W" may rest on the subnasale or columella in use, in the event of the seal forming portion shifting upwards (superiorly) in use, leaving clearance (e.g., indicated by c in <FIG> which is between an inner edge of the undercushion <NUM> and an inner surface of the plenum chamber) around the respective left and right subalare.

In an example, as best shown in Figs. <NUM>-<NUM>-<NUM>, <FIG>, and <FIG>, a portion of the sealing portion may have a question-mark shaped, sickle shaped, or c-shaped cross-section. The question-mark shaped, sickle shaped, or c-shaped cross-section may provide the sealing portion with greater range of movement or flexibility towards the patient's face in use. In the illustrated example, the question-mark shaped, sickle shaped, or c-shaped cross-section is provided to a lower portion of the undercushion <NUM> and/or the side wall region <NUM>, which provides a space below the lower portion of the undercushion <NUM> and adjacent the side wall region <NUM>. For example, the lower portion of the undercushion <NUM> is radially offset towards the outside of the side wall region <NUM>. It should be appreciated that such cross-section may be provided around the entire perimeter of the cushion or may only be provided in selected regions of the cushion, e.g., only in the top lip region. Also, the size and/or configuration of such cross-section may vary in selected regions.

In the illustrated example of <FIG> and <FIG>, D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>. -<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), and D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>). Although specific dimensions are provided, it is to be understood that these dimensions are merely exemplary and other dimensions are possible depending on application. For example, the exemplary dimensions may vary by +/-<NUM>-<NUM>% or more or less depending on application. For example, the sealing portion and aperture may be wider, e.g., D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), and D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>). In another example, the sealing portion and aperture may be narrower, e.g., D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>), and D<NUM> is about <NUM>-<NUM> (e.g., about <NUM>).

In accordance with another form of the present technology seal forming structure <NUM> comprises sealing region <NUM>. Sealing region <NUM> may be adapted to interface with the patient and form a seal with the patient's airways. Sealing region <NUM> may include a nose ridge or nose ridge region <NUM>, sides of the nose region <NUM>, corners of the nose region <NUM> and top lip region <NUM>. Sealing region <NUM> may comprise a membrane or flap type seal <NUM>. In an example, as shown in <FIG>, the inner edge of the membrane <NUM> may includes a bead <NUM>-<NUM>, e.g., to prevent tearing, enhance sealing along the edge. Sealing region <NUM> may further comprise an undercushion or backup band <NUM>, extending around part of or the entire perimeter of the sealing region. A further aspect of the present technology is a cushion for a mask that seals at its upper extent in a region of the nose that is generally above the tip of the nose, and extends across the alar or flares of the patient's nose.

In an example, sealing region <NUM> may be preformed or otherwise pre-shaped so as to conform to that patient's facial topography.

One aspect of the present technology relates to sealing of the sealing region in the nose ridge region. In an example, the sealing region in the nose ridge region is adapted to engage along the nasal ridge between the pronasale and sellion, and along the nasal cartilage region of the nasal ridge and below or inferior to the nasal bone. That is, the nasal mask system is constructed to have a seal-forming region that is substantially on at least part of the cartilaginous framework of the patient's nose and not on the nasal bone, i.e., seal along nasal ridge without contacting nasal bridge/skin on the nasal bone.

For example, the sealing region <NUM> is adapted to be positioned and seal at-its upper extent in a region of the nose that is generally above the tip of the nose (i.e., above the pronasale), and extends across the alar or flares of the patient's nose, e.g., not extending over or across the bone of the patient's nose.

In an example, the sealing region <NUM> is positioned at its upper extent in a region of the nose that is generally close to the junction between bone and cartilage on a range of people with larger noses, and avoids impinging on the sight of people with smaller noses.

Nose ridge region <NUM> may be adapted to engage with a nose ridge of a patient. In an example, the nose ridge region may be shaped or preformed to accommodate a patient's nose ridge, for example, as best shown on <FIG>, the nose ridge region may be lower (i.e., closer to the attachment region <NUM>) than the sides of the nose region <NUM>. Nose ridge region <NUM> may comprise a membrane <NUM> for sealing without an undercushion or backup band. In an example, such an arrangement prevents excess pressure on the sensitive nose ridge region. In an example, the membrane at the nose ridge region <NUM> may be relatively longer that the membrane in other regions of the seal region, for example the top lip region <NUM>. The membrane in the nose ridge region <NUM> may be, for example, about <NUM>-<NUM> in length. In an example, the membrane in the nose ridge region <NUM> may be about <NUM>-<NUM> in length. In an example, the membrane in the nose ridge region <NUM> may be about <NUM> in length.

Sides of the nose region <NUM> may be adapted to engage with the sides of a patient's nose. In an example, sides of the nose region <NUM> may be preformed to accommodate the sides of the patient's nose and potentially their cheeks. As best shown on <FIG>, sides of nose the region <NUM> extends from the apex of the cushion at nose ridge region <NUM> to the corners of the nose region <NUM>. The sides of nose the region <NUM> slopes upwardly from the nose ridge region <NUM> to the corners of the nose region, see for example <FIG>. Sides of the nose region <NUM> may comprise a membrane <NUM> for sealing without an undercushion or backup band. In an example, such arrangement prevents excess pressure on the sides of the patient's nose or alar or flares. Excess pressure on these regions may cause the cartilage of the nose to collapse inwardly towards the septum, thereby occluding or partially occluding the patient's airway.

Corners of the nose region <NUM> may be adapted to form a seal with the corners of the patient's nose. <FIG> shows the corners of the nose region <NUM> having an apex or point generally indicated by H<NUM>, being the maximum height of the sealing region <NUM>. This height is to ensure that the most force is applied to the sealing region <NUM> in the corners of the nose region <NUM>, as this is a boney region of the face and is therefore less sensitive to pressure. Furthermore, this region of the patient's face is particularly difficult to seal on as the geometry of the face in this region is quite complex, so the greater the force applied to the seal in this region, the more likely a seal will form. In addition, since lower sealing forces are required on the nose ridge region and the sides of the nose region (for comfort and to avoid occlusion), the sealing region must be anchored at the corners of the nose region. Corners of the nose region <NUM> may comprise a membrane or membrane seal <NUM> and an undercushion or backup band <NUM>. The use of both a membrane and an undercushion may ensure a higher sealing force in this region. In an example, the membrane may have a thickness about <NUM>-<NUM>, for example about <NUM>. In an example, the undercushion may have a thickness of about <NUM>-<NUM>.

Top lip region <NUM> may be adapted to engage the surface between the patient's top lip and base of the nose. In an example, top lip region may have a relatively shorter membrane length than the nose ridge region, for example a length of about <NUM>-<NUM>, e.g., about <NUM>-<NUM>. In an example, this shorter membrane length may be advantageous as some patient's only have a small space between their top lip and the base of their nose. As best shown in <FIG>, top lip region <NUM> may have a membrane seal <NUM> and an undercushion or backup band <NUM>. The use of both a membrane and an undercushion may ensure a higher sealing force in this region. In an example, the membrane may have a thickness about <NUM>-<NUM>, for example about <NUM>. In an example, the undercushion may have a thickness of about <NUM>-<NUM>, for example about <NUM>. In an example, the thickness of the undercushion may vary along the length of the top lip region, for example from about <NUM> at the corners of the nose region, to about <NUM> at the centre of the top lip region.

Use of the undercushion or back-up band enables the membrane or facial flap to be made considerably thinner than if a single unsupported flap were used. This is highly advantageous in that a thinner flap is in turn more flexible, so as to feel softer and more comfortable and more readily conform to irregularities in the facial contour. It also permits the flap to more readily respond to system pressure in the breathing chamber acting on its underside to urge it into tight sealing engagement with the face.

As noted above, the nasal mask system is constructed to have a seal-forming region that is substantially on the cartilaginous framework on the nose (i.e., not on the nasal bone), and which does not block the nose. In an example, this may be achieved by providing a compression seal (e.g., using an undercushion structure) along the patient's top lip (e.g., inferior sealing portion) and not on the patient's nose. Seal on the patient's nose (e.g., superior sealing portion) may be achieved by tension in the membrane and/or a pneumatic seal.

For example, as shown in the cushion example of <FIG> and also described in the above example, the undercushion or backup band <NUM> is only provided in the top lip region <NUM> and the corners of the nose region <NUM> of the cushion, e.g., see <FIG>, <FIG>, <FIG>, <FIG>, <FIG>. That is, the sealing region includes a single layer or membrane <NUM> only structure in the nose ridge region <NUM> and sides of the nose region <NUM> (e.g., see <FIG> and <FIG>), and the sealing region includes a dual layer or membrane <NUM> and undercushion <NUM> structure in the top lip region <NUM> and corners of nose region <NUM>. The dual layer structure provides a compression seal along the top lip region and corners of nose region. In contrast, the nose ridge region and sides of the nose region uses tension in the membrane (edge of the membrane stretched into sealing engagement due to tension applied to membrane) and/or pressure in the breathing chamber acting on the membrane (pneumatic seal) to provide a seal. The single layer is also provided in the nose ridge region and sides of the nose region to provide a softer and more flexible seal that avoids any potential for blocking the patient's nose, i.e., prevents excess pressure on the sides of the patient's nose or alar or flares which may cause the cartilage to collapse inwardly and potentially at least partially occlude the patient's airway.

Thus, the cushion assembly according to an example of the present technology provides different sealing mechanisms in different portions of the cushion. For example, the cushion assembly may provide one mechanism of sealing in the superior portion of the cushion (e.g., sealing by tension in the membrane and/or a pneumatic seal) and a different mechanism of sealing in the inferior portion of the cushion (e.g., compression seal). In the illustrated example, the cushion assembly provides a compression seal via a dual layer or membrane and undercushion structure. However, it should be appreciated that the compression seal may be provided by alternative structures, e.g., gel-filled or foam-filled pocket, thicker single wall (e.g., about <NUM> to <NUM> thick silicone).

<FIG> shows an example of the cushion assembly <NUM> engaged with the patient's face and under pressure or inflated in use, i.e., supply of air at positive pressure being applied to the cushion assembly <NUM>. <FIG> shows a hatched area along the sealing portion of the cushion assembly which illustrates a width or contact area <NUM> of the sealing portion engaged with the patient's face in use. The width or contact area includes an inner edge <NUM>(i) (e.g., along the edge of the orifice) and an outer edge <NUM>(o). <FIG> also shows the outer edge <NUM>(o) of the contact area in dashed lines. As illustrated, a relatively narrow width of superior sealing portion <NUM> may engage with the nose ridge to form a seal, e.g., depending on the shape of the nose with which it is being used. A relatively wider portion of superior sealing portion <NUM> may engage with the skin adjacent lateral nasal cartilage to form a seal. In the inferior sealing portion <NUM>, substantially the entire width of the inferior sealing portion may engage the skin along the corner of nose region and top lip region to form a seal. Thus, the width or contact area of the sealing portion engaged with the patient's face in use may vary around the perimeter of the cushion assembly to form a seal.

In an example, as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>, each side of nose region <NUM> of the sealing region includes a portion <NUM>, e.g., a wing or sealing flap, that protrudes from the edge of the membrane <NUM> along its inner perimeter. As best shown in <FIG> and <FIG>, each sealing flap <NUM> is adapted to form a seal on the region adjacent the junction between the nasal greater alar cartilage and the lateral nasal cartilage of a patient's nose (also referred to as the alar crease). The exact location of the sealing flap on a face in use may vary depending on the size and shape of the nose with which it is being used.

As illustrated, each sealing flap <NUM> is at least partially angled or pre-biased outwardly away from the breathing chamber of the cushion. When engaged with the patient's nose, the sealing flaps are deflected towards the breathing chamber which provides a bias for sealing in the junction noted above. That is, the shape, flexibility, and pre-bias of the sealing flaps allows the flaps to accommodate changes in curvature or contour in this junction (e.g., which tend to continually vary when the nasal alar or "flare" in use) so as to maintain seal and prevent leaks in use.

In an example, the sealing flange (including membrane <NUM> and sealing flap <NUM>) defines a generally T-shaped orifice. The edge of the membrane <NUM> along its inner perimeter along with the edge of each sealing flap <NUM> along its inner perimeter cooperate to define an orifice <NUM> into the plenum chamber. In an example, such orifice <NUM> includes a general T-shape including an upper orifice portion <NUM>(<NUM>) (along vertical axis v as viewed in <FIG>) and a lower orifice portion <NUM>(<NUM>) (along horizontal axis h as viewed in <FIG>) that extends generally transverse to the upper orifice portion <NUM>(<NUM>).

As best shown in <FIG>, the sealing flap <NUM> changes the curvature and/or angle of the edge defining the orifice <NUM>, i.e., edge of the orifice <NUM> curves upwardly and outwardly away from the breathing chamber at least along the sealing flap <NUM>.

The curvature of the cushion may vary along the patient contacting surface of the membrane <NUM> in different regions of the cushion, e.g., to facilitate sealing in different regions of the patient's face.

For example, as shown in <FIG>, the nose ridge region <NUM> and the top lip region <NUM> each include at least a portion that is locally saddle-shaped in curvature, e.g., curves up in one direction d1 and curves down in a different direction d2. <FIG> is another view of the cushion <NUM> illustrating such saddle-shaped curvature in the nose ridge region <NUM> and the top lip region <NUM>.

It should be appreciated that the above-noted shapes of curvature are approximate shapes and should not be limited to strict mathematical definitions of such shapes.

In addition, it should be appreciated that regions may include similar curvature shapes, but the magnitudes of such curvature may be different. For example, the nose ridge region <NUM> and the top lip region <NUM> may both include at least a portion that is locally saddle-shaped, however the magnitude of curvature in one and/or both principle directions of such saddle-shape may be different in each region.

In an example, where a single mask should be used to fit about <NUM>% of the female population, the undercushion aperture width (e.g., indicated at uw in <FIG> for example) is about <NUM> to about <NUM>, or about <NUM> to about <NUM>. In an example, where a single mask should be used to fit about <NUM>% of the male population, the undercushion aperture width is about <NUM> to about <NUM>, or about <NUM> to about <NUM>. In one form, to account for nose width variations of various ethnicities, to fit up to <NUM>% of an average population, an undercushion aperture width is about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

In an example, where a single mask should be used to fit about <NUM>% of the female population, the membrane aperture width (e.g., indicated at mw in <FIG> for example) is about <NUM> to about <NUM>, or about <NUM> to about <NUM>. In an example, where a single mask should be used to fit about <NUM>% of the male population, the membrane aperture width is about <NUM> to about <NUM>, or about <NUM> to about <NUM>. In one form, to account for nose width variations of various ethnicities, to fit up to <NUM>% of an average population, a membrane aperture width is about <NUM> to about <NUM>, or about <NUM> to about <NUM>.

Plenum chamber <NUM> is formed in part by a side wall. In one form, the side wall includes side wall region <NUM> of sealing region <NUM>. The plenum chamber has a perimeter <NUM> that is shaped to conform generally to the surface contour of the face of an average person (e.g., see <FIG>). In use, a marginal edge <NUM> of the plenum chamber <NUM> is positioned in close proximity to an adjacent surface of the face (e.g., see <FIG>). Actual contact with the face is provided by the seal-forming structure <NUM>. In an example, the seal-forming structure <NUM> extends in use about the entire perimeter <NUM> of the plenum chamber <NUM>. In an example, the plenum chamber is adapted to receive a portion of the patient's nose including the pronasale, e.g., the plenum chamber forms over and surrounds a portion of the cartilaginous framework of the nose including the pronasale.

In an example, the walls of the plenum chamber <NUM> are flexible, or semi-rigid. In an example, plenum chamber <NUM> does not include a rigid frame or shell. In an example, the walls of the plenum chamber <NUM> are not rigid, and, e.g., the walls of the plenum chamber <NUM> are not floppy. In certain forms, flexibility of the walls of the plenum chamber <NUM> assists to decouple a tube drag force from disrupting a seal.

In one form, the walls of the plenum chamber <NUM> are moulded from a silicone rubber. In an example, the walls of the plenum chamber <NUM> are constructed from a silicone rubber with a Type A indentation hardness of about <NUM> to about <NUM>, and with a thickness in the range of about <NUM> to about <NUM>. In certain forms of the present technology, the plenum chamber <NUM> may have different thicknesses in different regions.

Side wall region <NUM> may extend between sealing region <NUM> and attachment region <NUM>. Side wall region may be generally conical, that is, it may have a first diameter at proximate attachment region <NUM> and a second diameter proximate seal region <NUM>, with the first diameter being less than the second diameter. Side wall region may have a thickness of about <NUM>-<NUM>, e.g., about <NUM>-<NUM>, e.g., about <NUM>. Such a thickness may provide some support to the seal region <NUM>, prevent the elbow assembly <NUM> contacting the patient's nose, and ensure that the cushion does not collapse from headgear tension when in use.

Side wall region <NUM> may connect or be formed with headgear connectors <NUM>. Such an arrangement may replace the need for a rigid frame or skeleton, as the headgear connectors are arrange proximal to the sealing region <NUM>. Headgear connectors <NUM> may be disposed on opposing sides of side wall <NUM>.

In an example, as best shown in <FIG>, <FIG>, <FIG>, and <FIG>, the side wall region <NUM> between the sealing region <NUM> and the attachment region <NUM> includes an area <NUM> adjacent the top lip region <NUM> of the sealing region that includes a thickness that is less than corresponding thicknesses adjacent the nose ridge, sides of nose, and corners of nose regions of the sealing region. That is, the area <NUM> includes a thinner walled cross-section adjacent the top lip region <NUM> of the sealing region. Such area <NUM> of thinner cross-section lessens the force provided by the sealing region along this section of the top lip region <NUM>. For example, such area <NUM> provides less pressure along the top lip region <NUM> than the corners of nose region <NUM> (i.e., stiffer along the corners of nose region than the top lip region thereby giving rise or effecting relatively greater pressure along the corners of nose region (along the corners of the lip adjacent the alars), in order to avoid excessive pressure on the columella or septum of the patient's nose which is a more sensitive region of the patient's nose.

<FIG> show exemplary cross-sectional views through various regions of the cushion assembly <NUM>. For example, <FIG> is a cross-sectional view through the nose ridge region <NUM> and the top lip region <NUM> showing the single layer or membrane <NUM> only structure in the nose ridge region <NUM> and the dual layer or membrane <NUM> and undercushion <NUM> structure in the top lip region <NUM>. <FIG> also shows the thinner cross-section area <NUM> in the side wall region <NUM> adjacent the top lip region <NUM>, e.g., to avoid excessive pressure on the columella or septum. In addition, <FIG> shows the attachment region <NUM> including thinner wall section <NUM>(<NUM>), e.g., to permit decoupling of tube drag forces. <FIG> show the single layer or membrane <NUM> only structure in the sides of the nose region <NUM>. <FIG> also show the single layer or membrane <NUM> only structure in the sides of the nose region <NUM> as well as at least part of the wing or sealing flap <NUM> that protrudes from the edge of the membrane <NUM>. <FIG> show at least part of the headgear connector <NUM>. <FIG> show the dual layer or membrane <NUM> and undercushion <NUM> structure in the corners of nose region <NUM> and the top lip region <NUM>. <FIG> shows the thinner cross-section area <NUM> in the side wall region <NUM> adjacent the top lip region <NUM>.

In an example, the seal-forming portion <NUM> of the patient interface <NUM> of the present technology is held in sealing position in use by the positioning and stabilising structure <NUM>.

In one form, the seal-forming portion <NUM> of the patient interface <NUM> of the present technology is held in sealing position via a two-point connection to a positioning and stabilising structure <NUM>.

In one form, the positioning and stabilising structure <NUM> connects to plenum chamber <NUM> via headgear connector <NUM>.

In an example, there are only two connectors <NUM> to the plenum chamber <NUM>.

Headgear connector <NUM> may comprise a lug or interface <NUM> adapted to receive a cushion connector <NUM> on headgear <NUM>. A similar arrangement is disclosed in PCT application number <CIT>.

Headgear connectors <NUM> may be positioned at an angle relative to the vertical axis of the seal region <NUM>. As best shown in <FIG>, headgear connectors <NUM> may be positioned at angle α relative to the vertical axis of the seal region <NUM>. In an example, angle α may be approximately <NUM>-<NUM>°. In an example, angle α may be approximately <NUM>-<NUM>°. In an example, angle α may be approximately <NUM>-<NUM>°. Angle α aligns the headgear connectors in such a way so as to ensure a sealing force between the cushion and the patient is sufficient to effect a seal without causing discomfort or causing the cushion to collapse (for example, the closer angle α is to <NUM>°, the more likely the cushion is to collapse inwardly towards the vertical axis when headgear tension is applied, thus pinching the patient's nose), particularly in the sides of the nose region <NUM> of sealing region <NUM>.

In an alternative example, as best shown in <FIG>, <FIG>,<FIG>, <FIG>, <FIG>, <FIG>, a hinge or thinner wall section <NUM>(<NUM>), <NUM>(<NUM>) may be provided to each headgear connector <NUM>, <NUM> to enhance flexibility of the headgear connectors and allow sufficient bending in use so headgear tensioning force is not transferred to collapse the cushion inwardly, e.g., to avoid pinching of the alar under headgear tension. Also, as shown in <FIG>, one or more wall sections <NUM>(<NUM>) of the side wall region <NUM> between the lugs of the headgear connectors may be thickened, e.g., to prevent or reduce collapse of the side wall region under headgear tension.

Headgear connectors <NUM> may be positioned at an angle relative to the horizontal axis of the seal region <NUM>. As best shown in <FIG>, headgear connectors <NUM> may be positioned at angle β relative to the horizontal axis of the seal region <NUM>. In an example, angle β may be approximately <NUM>-<NUM>°. In an example, angle β may be approximately <NUM>-<NUM>°. In an example, angle β may be approximately <NUM>-<NUM>°. Angle β aligns the headgear connectors in such a way so as to ensure the sealing force provided by the headgear connectors <NUM> is distributed over the sealing region <NUM>, with more force provided in the top lip region <NUM> and corners of the nose region <NUM>, and less force provided in the nose ridge region <NUM>. Such distribution may be more comfortable and stable.

As shown in <FIG>, headgear connectors <NUM> may have a first width w<NUM> at a region proximal to the side wall <NUM>, and a second width w<NUM> at its extremity, with first width w<NUM> being greater than second width w<NUM>. In an example, first width w<NUM> may be about <NUM>-<NUM>. In an example, first width w<NUM> may be about <NUM>-<NUM>. In an example, first width w<NUM> may be about <NUM>-<NUM>. In an example, second width w<NUM> may be about <NUM>-<NUM>. In an example, second width w<NUM> may be about <NUM>-<NUM>. In an example, second width w<NUM> may be about <NUM>-<NUM>. First width w<NUM> ensures that the force provided by the headgear is spread from the sides of the nose region <NUM> to the corners of the nose region <NUM>, and also stabilizes the cushion in the horizontal plane. Second width w<NUM> is arranged to reduce the visual bulk of the headgear connector <NUM> and permit connection with cushion connector <NUM>.

Headgear connectors <NUM> are advantageously disposed proximal to the sealing region <NUM>. Headgear connectors <NUM> are positioned at a height H<NUM> from the sealing region <NUM>, as shown on <FIG>. In an example, height H<NUM> may be approximately <NUM>-<NUM>. In an example, height H<NUM> may be approximately <NUM>-<NUM>. In an example, height H<NUM> may be approximately <NUM>-<NUM>. In an example, height H<NUM> may be approximately <NUM>-<NUM>. This arrangement ensures that headgear forces are translated directly to the sealing portion, and the sealing region is able to wrap or conform to the patient's nasal geometry.

The position and size of the headgear connectors directs the sealing force to the sealing region in such a way so as to negate or eliminate the need for a forehead support or vertical headgear strap. For example, the width of the headgear connectors proximal to the side wall stabilizes the sealing region on the patient's face. The height of the headgear connectors <NUM> to the sealing region <NUM> ensures that headgear forces are translated directly to the sealing portion, thereby eliminating the need for additional stabilization from a forehead support.

In an alternative form of the present technology, headgear connectors <NUM> are formed separately from the plenum chamber.

One form of positioning and stabilising structure <NUM> in accordance with the present technology is headgear assembly <NUM>. Headgear assembly <NUM> may be adapted to support, stabilize and/or position the cushion assembly <NUM> on the patient's face.

As shown in <FIG>, headgear assembly <NUM> may comprise a pair of side straps <NUM>, connected to a rear strap <NUM>. Side straps <NUM> define a main headgear loop that may be positioned along the sides of the patient's face, across the patient's cheeks, extending between the eyes and the ears of the patient, e.g., overlaying at least a portion of the zygomatic bone, towards the crown of the patient's head where it e.g., overlays a portion of the parietal bone. Side straps <NUM> may have a cushion connector <NUM> adapted to receive a headgear connector <NUM> of cushion <NUM>. Side straps <NUM> may have an adjustment portion <NUM>, wherein side straps <NUM> interlock or otherwise connect to each other and are able to adjust in length relative to one another. Rear strap <NUM> extends between the side straps and may loop through a respective slot <NUM> provided to the side straps <NUM>. Rear strap <NUM> defines a rear headgear loop that may be positioned over the back of the patient's head, e.g., engaging along or below the patient's occiput. In an example, a portion of the headgear rear strap <NUM> or rear headgear loop overlays or engages a point on the head below or inferior to the occipital bone, e.g. a portion of the strap lies on a portion of the trapezius muscle, adjacent the occipital bone in use. In an example, at least a portion of the rear strap <NUM> engages below or inferior a lower edge of the occipital bone, which lower edge helps to maintain the rear strap in position and prevent the rear strap from riding up the patient's head, e.g., prevent sliding in a superior direction. Refer to <FIG> and <FIG> for location of the trapezius and an exemplary positioning of the rear strap <NUM> along a portion of the trapezius. In an example, the headgear straps are sufficiently stretchy or flexible, e.g., to enhance comfort and adjustability. For example, the headgear may not require length adjustment to don.

In one form, headgear assembly <NUM> comprises a silicone main portion and a fabric rear portion. In another form, headgear assembly <NUM> comprises a fabric main portion and a fabric rear portion. In another form, headgear assembly <NUM> comprises a silicone main portion and a silicone rear portion.

In one form, headgear assembly <NUM> is constructed and arranged to be substantially floppy.

In one form, headgear assembly <NUM> comprises a main structural tie, and a rear structural tie.

An exemplary headgear assembly <NUM> is disclosed in PCT application number <CIT>.

In one form, the patient interface <NUM> includes a vent <NUM> constructed and arranged to allow for the washout of exhaled carbon dioxide.

One form of vent <NUM> in accordance with the present technology comprises a plurality of holes, for example, about <NUM> to about <NUM> holes, or about <NUM> to about <NUM> holes, or about <NUM> to about <NUM> holes.

In an example, the vent <NUM> is located in a decoupling structure <NUM>, e.g. a swivel <NUM>. Alternatively, the vent <NUM> is located in the plenum chamber <NUM>.

One form of vent <NUM> in accordance with the present technology is vent <NUM>. Vent <NUM> may permit to expiration of exhaled gases from the nasal mask system. Vent <NUM> may comprise a series of holes, a mesh or other arrangement adapted to permit the flow of gas. In an example, vent <NUM> may be sufficiently rigid to avoid collapse of the air channels that exhaust the exhaled gas. Vent <NUM> may be positioned on the elbow <NUM> or other region such as the air delivery tube assembly <NUM> or cushion assembly <NUM> (including, for example, side wall <NUM>).

In certain forms of the present technology, the vent <NUM> may be constructed from a flexible, or floppy material that is supported by a sufficiently rigid frame to avoid collapse of the air channels that exhaust the exhaled gas.

In an alternative form, the patient interface <NUM> does not include a vent.

In one form the patient interface <NUM> includes at least one decoupling structure <NUM>, for example a swivel <NUM> or a ball and socket <NUM> (e.g., see <FIG>). In one form, decoupling structure <NUM> may be formed at least in part by attachment region <NUM>.

Attachment region <NUM> may be adapted to receive elbow assembly <NUM>. Attachment region <NUM> may include a thinner wall section <NUM>(<NUM>) than the side wall region <NUM>, for example attachment region <NUM> may have a wall section of about <NUM>-<NUM>, for example about <NUM>-<NUM>, for example about <NUM>. In an example, the thinner wall section is configured to permit decoupling of the tube drag forces from the sealing forces.

In one form, connection port <NUM> to air circuit <NUM> is made by elbow assembly <NUM> (e.g., see <FIG> and <FIG>).

Elbow assembly <NUM> may be adapted to connect or serve as an interface between the cushion assembly <NUM> and the air delivery assembly <NUM>. Elbow assembly <NUM> may be formed with or integral with the air delivery assembly <NUM>, or cushion assembly <NUM>. Elbow assembly <NUM> may also be adapted to permit exhaust of exhaled gases.

As shown in <FIG> and <FIG>, elbow assembly <NUM> may comprise an elbow <NUM>, the elbow having a vent <NUM>, the elbow connecting to or otherwise formed with connector ring <NUM>. Elbow <NUM> may be formed with a ball joint and the connector ring <NUM> may for constructed and arranged to permit rotation of the ball joint while ensuring a sufficient seal with the elbow to ensure air leakage does not compromise the patient's treatment pressure. The ball joint provides a decoupling mechanism, e.g., decouple tube drag forces from sealing forces.

Elbow <NUM> may also be attached to or otherwise connected with swivel <NUM>, adapted to receive an air delivery tube assembly <NUM>. Swivel <NUM> may be arranged such that it may form a seal or have a low leak with elbow <NUM>, while still being able to freely rotate relative to elbow <NUM>.

In an example, the patient interface <NUM> does not include a forehead support, however in one alternative form, a forehead support may be included.

In one form, the patient interface <NUM> includes an anti-asphyxia valve.

In one form of the present technology, a patient interface <NUM> includes one or more ports, that allow access to the volume within the plenum chamber <NUM>. In one form this allows a clinician to supply supplemental oxygen. In one form this allows for the direct measurement of a property gases within the plenum chamber <NUM>, such as the pressure.

An air circuit <NUM> in accordance with one form of the present technology is air delivery assembly <NUM>. Air delivery assembly <NUM> may be constructed to connect a flow generator to mask system <NUM>. As shown in <FIG>, air delivery system <NUM> may comprise a tube <NUM> and a connector <NUM>. Tube <NUM> may be relatively flexible. Connector <NUM> may be adapted to receive swivel <NUM> of elbow assembly <NUM>.

The nasal mask system provides a small, unobtrusive mask system that is easy to don, easy to remove, is stable, comfortable, effective, provides wide-fit range, unobtrusive, easy to use, and adjustable. In addition, the nasal mask system provides a non-prong or non-pillows arrangement (i.e., nasal mask system provides nasal-type cushion that provides single orifice adapted to surround both nares in use) that does not suffer from problems of jetting effect, nor the potential discomfort associated with nasal prongs or pillows adapted to at least partially extend up the patient's nose. The nasal mask system is structured such that little or no adjustment may be needed to fit the nasal mask system to the patient's head. In an example, no forehead support is provided to the mask system, though one can be provided if desired.

In the illustrated example, the nasal mask system <NUM> provides a two-point connection with the cushion, i.e., two side straps <NUM> of the headgear assembly engage respective headgear connector <NUM> along side of the cushion <NUM> (e.g., see <FIG>). The headgear assembly provides three adjustment points, e.g., adjustable portion <NUM> of the side straps <NUM> and respective adjustability of ends of the rear strap <NUM> with a respective slot <NUM> of the side straps <NUM>. However, it should be appreciated that more or fewer adjustment points may be provided, e.g., side straps and rear strap may provide fixed length with no adjustability.

In an example, the two-point connection does not does not require engagement or disengagement of a clip in order to don or remove the mask system, i.e., no clips are provided to the mask system but they can be provided if desired. Also, the main headgear loop defined by the side straps <NUM> extends from an inferior anterior position to a superior posterior position, which avoids any headgear strap extending below the ears (i.e., straps do not pass inferior to the patient's ear) as described below.

<FIG> provide a sequence of views to illustrate an exemplary method for fitting the nasal mask system to a patient, e.g. prior to the application of air pressure to the plenum chamber. As shown in <FIG>, the patient may grasp the nasal mask system such that one hand holds the cushion assembly <NUM> in a manner to orient the sealing region towards the patient's face and the other hand holds the rear strap <NUM> in a manner to allow the main headgear loop defined by the side straps <NUM> to receive the patient's head. Then, as shown in <FIG>, the cushion assembly is engaged with the patient's face, and the rear strap is held over the patient's head as it passes through the main headgear loop. The rear strap, along with the side straps attached thereto, may be pulled onto the patient's head until the rear strap is positioned along the back of the patient's head as shown in <FIG>, i.e., straps rotated or pivoted about the cushion assembly onto the patient's head until the straps engage and self-locate onto the patient's head. Finally, as shown in <FIG>, ends of the rear strap <NUM> and/or the adjustment portion <NUM> of the side straps may be adjusted as necessary to secure the nasal mask system on the patient's head.

This arrangement is simple to put on and take off as the straps do not have to be pulled down over the ears to don the mask system or pulled up over the ears to remove the mask system, i.e., headgear straps easily slid on/off over the patient's head like a cap. That is, the mask system includes headgear that may be donned and removed like a cap without interfering with the ears of the patient.

In use, the side straps <NUM> are arranged to pull the nasal mask system in a superior posterior direction (e.g., as indicated by the arrow al in <FIG>), which provides less compressive force along the nose ridge region of the cushion assembly <NUM> which is advantageous as such region is along a more sensitive region of the patient's nose, i.e., along the cartilage of the nose (not bone) as described above. Masks with nasal-type cushions normally include headgear arrangements arranged to pull the mask along a direction that is substantially parallel to Frankfort horizontal (as indicated by the arrow a2 in <FIG>) so as to provide a compressive sealing force substantially normal to the patient's face. To provide such force, the headgear arrangement includes straps that extend under the patient's ears so as to provide such force along the Frankfort horizontal direction. In the mask system according to an example of the present technology, the headgear assembly is arranged to pull the mask along the superior posterior direction, e.g., like an "under the nose" mask (e.g., pillows or cradle), which provides less compressive force along the nose ridge region while maintaining sufficient seal as noted above. Thus, the nasal mask system provides headgear that provides an effective sealing vector similar to "under the nose" masks (i.e., not parallel to Frankfort horizontal), but instead used for mask that covers part of the nose, i.e., the nasal mask system compromises sealing force strictly along the Frankfort horizontal for an over the ear headgear arrangement to facilitate donning.

<FIG> shows a perpendicular distance h<NUM> between a headgear connection point hp, i.e., line of headgear tension as headgear connects to the cushion assembly <NUM>, and a pivoting point or rotation axis pp of the cushion assembly <NUM> on the face, i.e., the top lip. This perpendicular distance h<NUM> allows adjustment of the headgear tension to effect rotational or pivotal adjustment of the plenum chamber/cushion assembly about the pivoting point pp. As illustrated, the headgear connection point hp is superior to the pivoting point pp or point of contact of the cushion assembly with the top lip. This arrangement enables a user to rotate/pivot the cushion assembly via adjustment of headgear tension and to use only a two point headgear connection to accommodate different nose ridge geometry. In an example, increasing the perpendicular distance h<NUM> will increase the moment.

A PAP device <NUM> in accordance with one aspect of the present technology comprises mechanical and pneumatic components, electrical components and is programmed to execute one or more algorithms. In an example, PAP device has an external housing, e.g., formed in two parts, an upper portion <NUM> of the external housing, and a lower portion <NUM> of the external housing. In alternative forms, the external housing may include one or more panel(s) <NUM>. In an example, the PAP device <NUM> comprises a chassis <NUM> that supports one or more internal components of the PAP device <NUM>. In one form a pneumatic block is supported by, or formed as part of the chassis <NUM>. The PAP device <NUM> may include a handle <NUM>.

In an example, pneumatic path of the PAP device <NUM> comprises an inlet air filter <NUM>, an inlet muffler, a controllable source of air at positive pressure (e.g., a blower <NUM>), and an outlet muffler. One or more pressure sensors and flow sensors are included in the pneumatic path.

In an example, pneumatic block comprises a portion of the pneumatic path that is located within the external housing.

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

The processor of the PAP device <NUM> is programmed to execute a series of algorithm modules in use, e.g., including pre-processing transducer signals module, a therapy engine module, a pressure control module, and further e.g., a fault condition module.

In certain forms of the present technology, one or more of the following definitions may apply.

Air: Air will be taken to include breathable gases, for example air with supplemental oxygen.

Positive Airway Pressure (PAP): PAP treatment will be taken to mean the application of a supply of air or breathable gas to the entrance to the airways at a pressure that is positive with respect to atmosphere. In one form, the pressure will be continuously positive (CPAP) and e.g., approximately constant 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 pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms the pressure will be a number of centimeters, e.g. about <NUM>-<NUM> of water pressure higher during inhalation than exhalation, and provide ventilatory support. 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.

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 Coming. 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.

When a particular material is identified as being preferably used or as being an example to construct a component, obvious alternative materials with similar. properties may be used as a substitute.

The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present technology is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

Moreover, in interpreting the disclosure, all terms should be interpreted in the broadest reasonable manner consistent with the context. In particular, 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 embodiments, it is to be understood that these embodiments 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 embodiments and that other arrangements may be devised without departing from the scope of the technology The invention is defined by the claims which follow.

Claim 1:
A patient interface (<NUM>) configured to deliver a supply of air at positive pressure to an entrance of a patient's airways, the patient interface (<NUM>) comprising:
(i) a nasal mask including a seal forming portion (<NUM>) constructed and arranged to form a seal on a portion of an upper lip of a patient, and to form a seal on a portion of a cartilaginous framework of a patient's nose, the nasal mask further including a plenum chamber (<NUM>) adapted to receive a portion of the patient's nose including the pronasale,
wherein the plenum chamber (<NUM>) is pressurizable to a therapeutic pressure above ambient air pressure,
wherein the plenum chamber (<NUM>) includes an attachment region (<NUM>) configured to connect or otherwise attach to an air delivery system,
wherein the plenum chamber (<NUM>) further includes a side wall region (<NUM>) extending between the seal forming portion (<NUM>) and the attachment region (<NUM>),
wherein the seal forming portion (<NUM>) and the plenum chamber (<NUM>) are moulded in one piece,
wherein the seal forming portion (<NUM>) and the plenum chamber (<NUM>) comprise a flexible elastomer or rubber, and
wherein the nasal mask further comprises a pair of headgear connectors (<NUM>), each of the pair of headgear connectors (<NUM>) being integrally formed with the side wall region (<NUM>) of the plenum chamber (<NUM>); and
(ii) a positioning and stabilising structure (<NUM>) including a pair of side straps (<NUM>) that provide a two-point connection to the nasal mask, and
wherein the positioning and stabilizing structure (<NUM>) is constructed and arranged to be donned or removed without the pair of side straps (<NUM>) passing inferior to the patient's ears.