Patient interface

Abstract

The invention is a decoupling structure for a patient interface, such as a nasal mask or a oro-nasal mask, that is configured with a vent structure. This is arranged to allow washout gases from the patient interface to exit concentrically to the air circuit that is received at one end of the decoupling structure. Also disclosed are examples of patient interfaces including the decoupling structure, a frame and a cushion module. The frame may comprise a pad and a rigidising material provided to the pad. The rigidising material may form a central portion of the frame. Also disclosed are examples of seal-forming structures having patient-contacting regions with varying thicknesses.

Description

Ref: P2755WO1 / 506986PCT1PATIENT INTERFACE

[0001] The application claims priority to Singaporean Patent Application No. 10202500150S filed 17 January 2025, Australian Patent Application No. 2025903819 filed 22 August 2025, and Australian Patent Application No. 2025905397 filed 11 November 2025, the entire contents of each of which is hereby incorporated by reference.1 BACKGROUND OF THE TECHNOLOGY1.1 FIELD OF THE TECHNOLOGY

[0002] The present technology relates to one or more of the screening, diagnosis, monitoring, treatment, prevention and amelioration of respiratory-related disorders. The present technology also relates to medical devices or apparatus, and their use. 1.2 DESCRIPTION OF THE RELATED ART1.2.1 Human Respiratory System and its Disorders

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

[0004] The airways include a series of branching tubes, which become narrower, shorter and more numerous as they penetrate deeper into the lung. The prime function of the lung is gas exchange, allowing oxygen to move from the inhaled air into the venous blood and carbon dioxide to move in the opposite direction. The trachea divides into right and left main bronchi, which further divide eventually into terminal bronchioles. The bronchi make up the conducting airways, and do not take part in gas exchange. Further divisions of the airways lead to the respiratory bronchioles, and eventually to the alveoli. The alveolated region of the lung is where the gas exchange takes place, and is referred to as the respiratory zone. See “Respiratory Physiology”, by John B. West, Lippincott Williams & Wilkins, 9th edition published 2012.

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

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

[0007] A range of therapies have been used to treat or ameliorate such conditions. Furthermore, otherwise healthy individuals may take advantage of such therapies toA2578192 12.0 1Ref: P2755WO1 / 506986PCT1prevent respiratory disorders from arising. However, these have a number of shortcomings.1.2.2 Therapies

[0008] 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.1.2.2.1 Respiratory pressure therapies

[0009] 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).

[0010] 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.1.2.3 Respiratory Therapy Systems

[0011] 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.

[0012] 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.1.2.3.1 Patient Interface

[0013] A patient interface may be used to interface respiratory equipment to its wearer, for example by providing a flow of air to an entrance to the airways. The flow of air may be provided via a mask to the nose and / or mouth, a tube to the mouth or a tracheostomy tube to the trachea of a patient. Depending upon the therapy to be applied, the patient interface may form a seal, e.g., with a region of the patient's face,A2578192 12.0 2Ref: P2755WO1 / 506986PCT1to facilitate the delivery of gas at a pressure at sufficient variance with ambient pressure to effect therapy, e.g., at a positive pressure of about 10 cmH20 relative to ambient pressure. For other forms of therapy, such as the delivery of oxygen, the patient interface may not include a seal sufficient to facilitate delivery to the airways of a supply of gas at a positive pressure of about 10 cmH20. For flow therapies such as nasal HFT, the patient interface is configured to insufflate the nares but specifically to avoid a complete seal. One example of such a patient interface is a nasal cannula.

[0014] Certain mask systems may be functionally unsuitable for the present field. For example, purely ornamental masks may be unable to maintain a suitable pressure. Mask systems used for underwater swimming or diving may be configured to guard against ingress of water from an external higher pressure, but not to maintain air internally at a higher pressure than ambient.

[0015] Certain masks may be clinically unfavourable for the present technology e.g. if they block airflow via the nose and only allow it via the mouth.

[0016] Certain masks may be uncomfortable or impractical for the present technology if they require a patient to insert a portion of a mask structure in their mouth to create and maintain a seal via their lips.

[0017] Certain masks may be impractical for use while sleeping, e.g. for sleeping while lying on one’s side in bed with a head on a pillow.

[0018] Certain masks may cause some patients a feeling of claustrophobia, unease and / or may feel overly obtrusive.

[0019] The design of a patient interface presents a number of challenges. The face has a complex three-dimensional shape. The size and shape of noses and heads varies considerably between individuals. Since the head includes bone, cartilage and soft tissue, different regions of the face respond differently to mechanical forces. The jaw or mandible may move relative to other bones of the skull. The whole head may move during the course of a period of respiratory therapy.

[0020] Consequently, some masks suffer from being obtrusive, aesthetically undesirable, costly, poorly fitting, difficult to use, and / or uncomfortable especially when worn for long or when a patient is unfamiliar with a system. Wrongly sized masks can give rise to reduced compliance, reduced comfort and poorer patient outcomes. Masks designed solely for aviators, masks designed as part of personal protection equipment (e.g. filter masks), SCUBA masks, or for the administration of anaesthetics may be tolerable for their original application, but nevertheless suchA2578192 12.0 3Ref: P2755WO1 / 506986PCT1masks may be undesirably uncomfortable to be worn for extended periods of time, e.g., several hours. This discomfort may lead to a reduction in patient compliance with therapy, especially if the mask is to be worn during sleep.

[0021] CPAP therapy is highly effective to treat certain respiratory disorders, provided patients comply with therapy. If a mask is uncomfortable, or difficult to use a patient may not comply with therapy. Since it is often recommended that a patient regularly wash their mask, if a mask is difficult to clean (e.g., difficult to assemble or disassemble), patients may not clean their mask and this may impact on patient compliance.

[0022] While a mask for other applications (e.g. aviators) may not be suitable for use in treating sleep disordered breathing, a mask designed for use in treating sleep disordered breathing may be suitable for other applications.

[0023] For these reasons, patient interfaces for delivery of CPAP during sleep form a distinct field.1.2.3.1.1 Seal-forming structure

[0024] Patient interfaces may include a seal-forming structure. Since it is in direct contact with the patient’s face, the shape and configuration of the seal -forming structure can have a direct impact the effectiveness and comfort of the patient interface.

[0025] A patient interface may be partly characterised according to the design intent of where the seal-forming structure is to engage with the face in use. In one form of patient interface, a seal-forming structure may comprise a first sub-portion to form a seal around the left naris and a second sub-portion to form a seal around the right naris. In one form of patient interface, a seal-forming structure may comprise a single element that surrounds both nares in use. Such single element may be designed to for example overlay an upper lip region and a nasal bridge region of a face. In one form of patient interface a seal-forming structure may comprise an element that surrounds a mouth region in use, e.g. by forming a seal on a lower lip region of a face. In one form of patient interface, a seal-forming structure may comprise a single element that surrounds both nares and a mouth region in use. These different types of patient interfaces may be known by a variety of names by their manufacturer including nasal masks, full-face masks, nasal pillows, nasal puffs and oro-nasal masks.A2578192 12.0 4Ref: P2755WO1 / 506986PCT1

[0026] A seal -forming structure that may be effective in one region of a patient’s face may be inappropriate in another region, e.g. because of the different shape, structure, variability and sensitivity regions of the patient’s face. For example, a seal on swimming goggles that overlays a patient’s forehead may not be appropriate to use on a patient’s nose.

[0027] Certain seal-forming structures may be designed for mass manufacture such that one design is able to fit and be comfortable and effective for a wide range of different face shapes and sizes. To the extent to which there is a mismatch between the shape of the patient’s face, and the seal-forming structure of the mass-manufactured patient interface, one or both must adapt in order for a seal to form.

[0028] One type of seal-forming structure extends around the periphery of the patient interface, and is intended to seal against the patient's face when force is applied to the patient interface with the seal-forming structure in confronting engagement with the patient's face. The seal-forming structure may include an air or fluid filled cushion, or a moulded or formed surface of a resilient seal element made of an elastomer such as a rubber. With this type of seal-forming structure, if the fit is not adequate, there will be gaps between the seal-forming structure and the face, and additional force will be required to force the patient interface against the face in order to achieve a seal.

[0029] Another type of seal-forming structure incorporates a flap seal of thin material positioned about the periphery of the mask so as to provide a self-sealing action against the face of the patient when positive pressure is applied within the mask. Like the previous style of seal forming portion, if the match between the face and the mask is not good, additional force may be required to achieve a seal, or the mask may leak. Furthermore, if the shape of the seal-forming structure does not match that of the patient, it may crease or buckle in use, giving rise to leaks.

[0030] Another type of seal-forming structure may comprise a friction-fit element, e.g. for insertion into a naris, however some patients find these uncomfortable.

[0031] Another form of seal-forming structure may use adhesive to achieve a seal. Some patients may find it inconvenient to constantly apply and remove an adhesive to their face.A2578192 12.0 5Ref: P2755WO1 / 506986PCT1

[0032] A range of patient interface seal-forming structure technologies are disclosed in the following patent applications: WO 1998 / 004310; WO 2006 / 074513; WO 2010 / 135785. / .2.3.1.2 Positioning and Stabilising Structure

[0033] A seal-forming structure of a patient interface used for positive air pressure therapy is subject to the corresponding force of the air pressure to disrupt a seal. Thus a variety of techniques have been used to position the seal-forming structure, and to maintain it in sealing relation with the appropriate portion of the face. Several factors may be considered when comparing different positioning and stabilising techniques. These include: how effective the technique is at maintaining the seal-forming structure in the desired position and in sealed engagement with the face during use of the patient interface; how comfortable the interface is for the patient; whether the patient feels intrusiveness and / or claustrophobia when wearing the patient interface; and aesthetic appeal.

[0034] One technique is the use of adhesives, e.g. see US Patent Application Publication No. US 2010 / 0000534. However, the use of adhesives may be uncomfortable for some.

[0035] Another technique is the use of one or more straps and / or stabilising harnesses. Many such harnesses suffer from being one or more of ill-fitting, bulky, uncomfortable and awkward to use.1.2.3.1.3 Pressurised Air Conduit

[0036] In one type of treatment system, a flow of pressurised air is provided to a patient interface through a conduit in an air circuit that fluidly connects to the patient interface at a location that is in front of the patient’s face when the patient interface is positioned on the patient’s face during use. The conduit may extend from the patient interface forwards away from the patient’s face.1.2.3.2 Respiratory Pressure Therapy (RPT) Device

[0037] 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.A2578192 12.0 6Ref: P2755WO1 / 506986PCT11.2.3.3 Air circuit

[0038] 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.1.2.3.4 Humidifier

[0039] 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.1.2.3.5 Vent technologies

[0040] Some forms of patient interface may include a vent to allow the washout of exhaled carbon dioxide. The vent may allow a flow of gas from an interior space of a patient interface, e.g., the plenum chamber, to an exterior of the patient interface, e.g., to ambient.

[0041] The vent may comprise one or more orifices and gas may flow through the orifice in use of the mask. Many such vents are noisy and may affect the sleep patterns of the patient. Some vents may also be disruptive of the sleep of a bed partner 1100 of the patient 1000, for example, either through noise or focussed flow of exhaled gases emanating from the vent.2 BRIEF SUMMARY OF THE TECHNOLOGY

[0042] 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.

[0043] A first aspect of the present technology relates to apparatus used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of a respiratory disorder.

[0044] Another aspect of the present technology relates to methods used in the screening, diagnosis, monitoring, amelioration, treatment or prevention of a respiratory disorder.A2578192 12.0 7Ref: P2755WO1 / 506986PCT1

[0045] 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.

[0046] One form of the present technology comprises a positioning and stabilising structure configured to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient’s head. The positioning and stabilising structure includes at least one strap.

[0047] One form of the present technology comprises a patient interface comprising a plenum chamber, a seal-forming structure, and a positioning and stabilising structure.

[0048] One form of the present technology comprises patient interface comprising a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure. The plenum chamber includes at least one plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient. The patient interface also comprises a seal-forming structure that is constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways. The seal-forming structure has a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares. The seal-forming structure is constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use. The patient interface also comprises a positioning and stabilising structure to provide a force to hold the seal-forming structure in a therapeutically effective position on the patient’s head.

[0049] Another aspect of one form of the present technology is a series of modular elements that may be interconnected in order to form different styles of patient interfaces.

[0050] In one form, there are at least two versions or styles of each modular element. The versions or styles may be interchangeably used with one another in order to form different modular assemblies.

[0051] One form of the present technology is a connector assembly for use with a patient interface.

[0052] Another aspect of one form of the present technology is a decoupling structure configured for use with a patient interface, the patient interface being configured to deliver a flow of breathable gas at a positive pressure of at least 4A2578192 12.0 8Ref: P2755WO1 / 506986PCT1cmH20, or at least 10cmH2O, or at least 20 cmH20 to the airway of a patient for treatment of a respiratory illness.

[0053] Another aspect of one form of the present technology is a decoupling structure configured for use with a patient interface, , the decoupling structure configured to receive at least a portion of a downstream end of an air circuit delivering a flow of breathable gas at a positive pressure to the patient interface and including:a body at least partially defining an interior passage;wherein the body has a first end and a second end, the interior passage extending between the first end and the second end;wherein the body is configured to receive at least the portion of the downstream end of the air circuit at or within the second end of the body;wherein the portion of the downstream end of the air circuit is received within the second end of the body such that a gap is provided between an external surface of the end of the air circuit and an interior surface forming at least part of the interior passage of the body, the gap defining part of a flow path for a vent flow of gases from the patient interface.

[0054] In examples, the second end of the body is angled relative to the first end of the body.

[0055] In examples, the body and the patient interface comprise complementary snap-fit fittings.

[0056] In examples, the complementary snap-fit fittings are arranged such that when engaged, the body of the decoupling structure may be able to rotate relative to the patient interface.

[0057] In examples, the downstream end of the air circuit is concentrically received within the second end of the body of the decoupling structure.

[0058] In examples, the body comprises a flange extending inwardly with respect to the interior surface of the body.

[0059] In examples, the flange has an inner circumference defining a bore that receives a connector configured to engage with the downstream end of the air circuit.

[0060] In examples, the flange has an inner circumference defining a bore that receives the downstream end of the air circuit.

[0061] In examples, the flange has a downstream side facing the patient interface and an upstream side facing the air circuit.A2578192 12.0 9Ref: P2755WO1 / 506986PCT1

[0062] In examples, the flange includes one or more apertures extending between the downstream side and upstream side.

[0063] In examples, the one or more apertures are communicative with the gap provided between the external surface of the end of the air circuit and the interior surface forming at least part of the interior passage of the body and forms part of the flow path for the vent flow of gases.

[0064] In examples, the decoupling structure comprises a diffuser element for diffusing the vent flow of gases.

[0065] In examples the diffuser element may be structured as an annular ring substantially complementary in profile to the flange of the body.

[0066] In examples, the diffuser is positioned between the upstream side of the flange and the connector configured to engage with the downstream end of the air circuit such that the diffuser element is in the path of the vent flow of gases from the patient interface.

[0067] In examples, the diffuser is positioned between the upstream side of the flange and the downstream end of the air circuit such that the diffuser element is in the path of the vent flow of gases from the patient interface.

[0068] Another aspect of the present technology comprises a patient interface for treatment of sleep disordered breathing, the patient interface comprising:a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure, the plenum chamber including at least one plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient;a seal-forming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways, the seal -forming structure having a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares, the seal-forming structure being constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use;a positioning and stabilising structure to provide a force to hold the sealforming structure in a therapeutically effective position on the patient’s head, theA2578192 12.0 10Ref: P2755WO1 / 506986PCT1positioning and stabilising structure comprising a frame and headgear connected to the frame;wherein the patient interface comprises a cushion module forming the sealforming structure and at least partially forming the plenum chamber, the cushion module being configured to connect to the frame in use;wherein the frame comprises a frame opening and the flow of air at the therapeutic pressure flows through the frame opening into the cushion module;wherein the cushion module comprises a cushion module connection portion defining an anterior opening and the frame comprises a frame connection portion, wherein the cushion module connection portion comprises a perimeter configured to sealingly engage a perimeter of the frame connection portion to fluidly connect the cushion module to the frame in use, the perimeter of the cushion module connection portion and the perimeter of the frame connection portion being correspondingly shaped perimeters;wherein the cushion module and frame comprise at least one pair of complementary features in addition to the correspondingly shaped perimeters, the at least one pair of complementary features preventing incorrect orientation of the cushion module with respect to the frame during assembly of the cushion module to the frame.

[0069] In examples:• the correspondingly shaped perimeters of the cushion module and frame are circular perimeters;• the cushion module connection portion comprises an inwardly facing lip and the frame connection portion comprises an outwardly facing channel structured to receive the inwardly facing lip;• the seal-forming structure is formed from a first material and the inwardly facing lip is formed from a second material having a greater hardness than the first material;• both the first material and the second material are elastomeric materials;A2578192 12.0 11Ref: P2755WO1 / 506986PCT1• the first material is a first silicone material and the second material is a second silicone material, the second silicone material having a greater durometer hardness than the first silicone material;• the at least one pair of complementary features comprises a protrusion and a recess, one of the protrusion and the recess being provided to the frame and the other of the protrusion and the recess being provided to the cushion module;• the at least one pair of complementary features comprises a superior pair of complementary features comprising a superior protrusion of the frame and a correspondingly shaped superior portion of the cushion module configured to receive the superior protrusion;• the correspondingly shaped superior portion of the cushion module is a recess;• the recess is recessed with respect to an exterior surface of the cushion module;• the at least one pair of complementary features comprises an inferior pair of complementary features comprising an inferior protrusion of the frame and a correspondingly shaped inferior portion of the cushion module configured to receive the inferior protrusion;• the correspondingly shaped inferior portion is defined between a pair of inferior protrusions of the cushion module, the inferior protrusions of the cushion module being positioned on respective lateral sides of the inferior protrusion of the frame; and / or• the inferior protrusions are provided internally to the cushion module.

[0070] Another aspect of the present technology comprises a frame for a patient interface for treatment of sleep disordered breathing, the frame comprising:a central portion configured to connect directly or indirectly to a cushion module of the patient interface, the cushion module at least partially forming a plenum chamber of the patient interface and comprising a seal-forming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways;a pair of arms extending from the central portion on respective lateral sides thereof, each arm comprising:A2578192 12.0 12Ref: P2755WO1 / 506986PCT1a medial portion connected at a medial end thereof to the central portion;a superior portion extending at least partially superiorly from a lateral end of the medial portion, the superior portion comprising a superior headgear connector at a superior end thereof; andan inferior portion extending at least partially inferiorly from the lateral end of the medial portion, the inferior portion comprising an inferior headgear connector at an inferior end thereof;a pad positioned to engage the user’s head in use, the pad forming at least part of the superior portion, the inferior portion and a junction between the superior portion, the inferior portion and the medial portion;a rigidising material attached to the pad in at least the superior portion, the inferior portion and the junction, the rigidising material comprising a junction rigidising portion located at the junction, a superior end rigidising portion located at or proximate the superior end of the superior portion, and an inferior end rigidising portion located at or proximate the inferior end of the inferior portion, the thickness of the rigidising material being greater in the junction rigidising portion than in the superior end rigidising portion and / or the inferior end rigidising portion.

[0071] In examples:• the thickness of the rigidising material is greater in the junction rigidising portion than in both the superior end rigidising portion and the inferior end rigidising portion;• the junction rigidising portion extends from the junction along at least half of the length of the superior portion;• the junction rigidising portion extends from the junction along more than half of the length of the superior portion;• the junction rigidising portion extends from the junction along at least half of the length of the inferior portion;A2578192 12.0 13Ref: P2755WO1 / 506986PCT1• the junction rigi dising portion extends from the junction along more than half of the length of the inferior portion;• the rigidising material has a thickness within the range of 1.5-2mm in the junction rigidising portion;• the rigidising material has a thickness within the range of 1.3-1 ,7mm in the superior end rigidising portion;• the rigidising material has a thickness within the range of 1.3-1 ,7mm in the inferior end rigidising portion;• the rigidising material comprises a posterior edge rigidising portion provided proximate a posterior edge of the pad, the rigidising material having a lesser thickness in the posterior edge rigidising portion than in the junction rigidising portion;• the rigidising material has a lesser thickness in the posterior edge rigidising portion than in the superior end rigidising portion;• the rigidising material has a lesser thickness in the posterior edge rigidising portion than in the inferior end rigidising portion;• the rigidising material has a thickness within the range of 0.4-lmm in the posterior edge rigidising portion;• the rigidising material is also attached to the pad in the medial portion, the rigidising material comprising a medial rigidising portion in the medial portion located medially of the junction rigidising portion;• the thickness of the rigidising material is greater in the junction rigidising portion than in the medial rigidising portion;• the rigidising material has a thickness within the range of 1.3-1 ,7mm in the medial rigidising portion;• in each arm, the rigidising material extends medially away from the pad to form a medial end of the arm;• the rigidising material is connected to the central portion of the frame;• the rigidising material is integrally formed with the central portion of the frame; and / or• the rigidising material is overmoulded to the pad.A2578192 12.0 14Ref: P2755WO1 / 506986PCT1

[0072] Another aspect of the present technology comprises a cushion module for a patient interface for treatment of sleep disordered breathing, the cushion module defining a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure, the cushion module comprising:a seal-forming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways, the seal -forming structure having a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares in use, the seal-forming structure being constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use, the seal-forming structure comprising:a nasal ridge portion positioned to seal to the patient’s nasal ridge in use;an inferior portion, wherein the inferior portion is positioned to seal to the patient’s lip superior or wherein the inferior portion is positioned to seal to the patient’s face against or inferior to the patient’s lip inferior;a pair of lateral patient-facing portions each connecting between the nasal ridge portion and the inferior portion on a respective lateral side of the cushion module;a pair of flaps each extending medially from a respective one of the lateral patient-facing portions and each positioned to engage a respective lateral side of the patient’s nose;wherein the seal-forming structure has a greater thickness in each of the pair of flaps than in the nasal ridge portion and / or the inferior portion.

[0073] In examples:• the seal-forming structure has a greater thickness in each of the pair of flaps than in the nasal ridge portion;• the seal-forming structure has a greater thickness in each of the pair of flaps than in the inferior portion;• the seal -forming structure has a thickness of between 0.2-0.3mm in the nasal ridge portion;A2578192 12.0 15Ref: P2755WO1 / 506986PCT1• the seal -forming structure has a thickness of between 0.2-0.3mm in the inferior portion;• the seal-forming structure has a thickness between 0.3-0.5mm in each of the flaps;• the seal-forming structure has a thickness between 0.3-0.4mm in each of the flaps;• the inferior portion is positioned to seal to the patient’s lip superior;• the seal-forming structure comprises a pair of inferolateral portions each in an inferior and lateral position on a respective lateral side of the seal-forming structure, each positioned laterally of the inferior portion of the seal-forming structure, the seal-forming structure having a greater thickness in the inferolateral portions than in the inferior portion;• each of the inferolateral portions increases in thickness away from the hole of the seal-forming structure;• the seal-forming structure comprises a pair of superolateral portions each on a respective lateral side of the seal-forming structure, each superolateral portion being positioned superiorly of the inferolateral portions and inferiorly of the nasal ridge portion, at least a portion of each superolateral portion being thicker than the nasal ridge portion;• each of the superolateral portions increases in thickness away from the hole of the seal-forming structure;• each of the superolateral portions is adjacent a respective one of the pair of flaps;• the seal -forming structure comprises a pair of lateral portions each on a respective lateral side of the seal-forming structure, each lateral portion being positioned at least partially inferior to a respective one of the superolateral portions and at least partially superior to a respective one of the inferolateral portions, the lateral portions being thicker than the inferolateral portions and / or the superolateral portions;• the seal-forming structure comprises a pair of superior stiffened portions each positioned on a respective lateral side of the seal-forming structure between the nasal ridge portion and a respective one of the superolateral portions, theA2578192 12.0 16Ref: P2755WO1 / 506986PCT1seal-forming structure having a greater thickness in each of the superior stiffened portions than in the nasal ridge portion;• a medial portion of each of the superior stiffened portions is greater in thickness than an adjacent portion of the respective superolateral portion; • each of the superior stiffened portions increases in thickness away from the hole of the seal-forming structure.

[0074] Another aspect of one form of the present technology is a patient interface configured to receive a flow of breathable gas having a positive pressure of at least 4 cmH20, or at least 10cmH2O, or at least 20 cmH20, the patient interface including a decoupling structure substantially as herein described configured to vent gases from the respiratory pressure system to ambient.

[0075] Another aspect of one form of the present technology is a respiratory pressure system comprising: a patient interface configured to receive a flow of breathable gas having a positive pressure of at least 4 cmH20, or at least 10cmH2O, or at least 20 cmH20; a flow generator configured to generate the flow of breathable gas; an air circuit configured to fluidly connect the patient interface to the flow generator; and a decoupling structure substantially as herein described configured to vent gases from the respiratory pressure system to ambient.

[0076] Another aspect of one form of the present technology is a patient interface that is moulded or otherwise constructed with a perimeter shape which is complementary to that of an intended wearer.

[0077] An aspect of one form of the present technology is a method of manufacturing apparatus.

[0078] Another aspect of one form of the present technology is a method of assembling a modular system comprising selecting a positioning and stabilising structure, and connecting the positioning and stabilising structure to either a first cushion or a second cushion.

[0079] An aspect of certain forms of the present technology is a medical device that is easy to use, e.g. by a person who does not have medical training, by a person who has limited dexterity, vision or by a person with limited experience in using this type of medical device.A2578192 12.0 17Ref: P2755WO1 / 506986PCT1

[0080] An aspect of one form of the present technology is a portable RPT device that may be carried by a person, e.g., around the home of the person.

[0081] An aspect of one form of the present technology is a patient interface that may be washed in a home of a patient, e.g., in soapy water, without requiring specialised cleaning equipment. An aspect of one form of the present technology is a humidifier tank that may be washed in a home of a patient, e.g., in soapy water, without requiring specialised cleaning equipment.

[0082] The methods, systems, devices and apparatus described may be implemented so as to improve the functionality of a processor, such as a processor of a specific purpose computer, respiratory monitor and / or a respiratory therapy apparatus. Moreover, the described methods, systems, devices and apparatus can provide improvements in the technological field of automated management, monitoring and / or treatment of respiratory conditions, including, for example, sleep disordered breathing.

[0083] Of course, portions of the aspects may form sub-aspects of the present technology. Also, various ones of the sub-aspects and / or aspects may be combined in various manners and also constitute additional aspects or sub-aspects of the present technology.

[0084] Other features of the technology will be apparent from consideration of the information contained in the following detailed description, abstract, drawings and claims.3 BRIEF DESCRIPTION OF THE DRAWINGS

[0085] The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements including:3.1 RESPIRATORY THERAPY SYSTEMS

[0086] Fig. 1 A shows a system including a patient 1000 wearing a patient interface 3000, in the form of nasal pillows, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device 4000 is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown. The patient is sleeping in a supine sleeping position.

[0087] Fig. IB shows a system including a patient 1000 wearing a patient interface 3000, in the form of a nasal mask, receiving a supply of air at positiveA2578192 12.0 18Ref: P2755WO1 / 506986PCT1pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000.

[0088] Fig. 1C shows a system including a patient 1000 wearing a patient interface 3000, in the form of a full -face mask, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. The patient is sleeping in a side sleeping position.3.2 RESPIRATORY SYSTEM AND FACIAL ANATOMY

[0089] Fig. 2A shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, alveolar sacs, heart and diaphragm.

[0090] Fig. 2B shows a view of a human upper airway including the nasal cavity, nasal bone, lateral nasal cartilage, greater alar cartilage, nostril, lip superior, lip inferior, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

[0091] Fig. 2C is a front view of a face with several features of surface anatomy identified including the lip superior, upper vermilion, lower vermilion, lip inferior, mouth width, endocanthion, a nasal ala, nasolabial sulcus and cheilion. Also indicated are the directions superior, inferior, radially inward and radially outward.3.3 PATIENT INTERFACE

[0092] Fig. 3 A shows a patient interface in the form of a nasal mask in accordance with one form of the present technology.

[0093] Fig. 3B shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a positive sign, and a relatively large magnitude when compared to the magnitude of the curvature shown in Fig. 3C.

[0094] Fig. 3C shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a positive sign, and a relatively small magnitude when compared to the magnitude of the curvature shown in Fig. 3B.

[0095] Fig. 3D shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a value of zero.A2578192 12.0 19Ref: P2755WO1 / 506986PCT1

[0096] Fig. 3E shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a negative sign, and a relatively small magnitude when compared to the magnitude of the curvature shown in Fig. 3F.

[0097] Fig. 3F shows a schematic of a cross-section through a structure at a point. An outward normal at the point is indicated. The curvature at the point has a negative sign, and a relatively large magnitude when compared to the magnitude of the curvature shown in Fig. 3E.

[0098] Fig. 3G shows a cushion for a mask that includes two pillows. An exterior surface of the cushion is indicated. An edge of the surface is indicated. Dome and saddle regions are indicated.

[0099] Fig. 3H shows a cushion for a mask. An exterior surface of the cushion is indicated. An edge of the surface is indicated. A path on the surface between points A and B is indicated. A straight line distance between A and B is indicated. Two saddle regions and a dome region are indicated.

[0100] Fig. 31 shows the surface of a structure, with a one dimensional hole in the surface. The illustrated plane curve forms the boundary of a one dimensional hole.

[0101] Fig. 3J shows a cross-section through the structure of Fig.31. The illustrated surface bounds a two dimensional hole in the structure of Fig. 31.

[0102] Fig. 3K shows a perspective view of the structure of Fig. 31, including the two dimensional hole and the one dimensional hole. Also shown is the surface that bounds a two dimensional hole in the structure of Fig. 31.

[0103] Fig. 3L shows a mask having an inflatable bladder as a cushion.

[0104] Fig. 3M shows a cross-section through the mask of Fig. 3L, and shows the interior surface of the bladder. The interior surface bounds the two dimensional hole in the mask.

[0105] Fig. 3N shows a further cross-section through the mask of Fig. 3L. The interior surface is also indicated.

[0106] Fig. 30 illustrates a left-hand rule.

[0107] Fig. 3P illustrates a right-hand rule.

[0108] Fig. 3Q shows a left ear, including the left ear helix.

[0109] Fig. 3R shows a right ear, including the right ear helix.

[0110] Fig. 3S shows a right-hand helix.A2578192 12.0 20Ref: P2755WO1 / 506986PCT1

[0111] Fig. 3T shows a view of a mask, including the sign of the torsion of the space curve defined by the edge of the sealing membrane in different regions of the mask.

[0112] Fig. 3U shows a view of a plenum chamber 3200 showing a sagittal plane and a mid-contact plane.

[0113] Fig. 3 V shows a view of a posterior of the plenum chamber of Fig. 3U. The direction of the view is normal to the mid-contact plane. The sagittal plane in Fig. 3 V bisects the plenum chamber into left-hand and right-hand sides.

[0114] Fig. 4 shows a cross-section through the plenum chamber of Fig. 3 V, the cross-section being taken at the sagittal plane shown in Fig. 3 V. A ‘mid-contact’ plane is shown. The mid-contact plane is perpendicular to the sagittal plane. The orientation of the mid-contact plane corresponds to the orientation of a chord 3210 which lies on the sagittal plane and just touches the cushion of the plenum chamber at two points on the sagittal plane: a superior point 3220 and an inferior point 3230. Depending on the geometry of the cushion in this region, the mid-contact plane may be a tangent at both the superior and inferior points.

[0115] Fig. 5 shows the plenum chamber 3200 of Fig. 3U in position for use on a face. The sagittal plane of the plenum chamber 3200 generally coincides with the midsagittal plane of the face when the plenum chamber is in position for use. The mid-contact plane corresponds generally to the ‘plane of the face’ when the plenum chamber is in position for use. In Fig. 5 the plenum chamber 3200 is that of a nasal mask, and the superior point 3220 sits approximately on the sellion, while the inferior point 3230 sits on the lip superior.

[0116] Fig. 6 shows a patient interface having conduit headgear, in accordance with one form of the present technology.3.4 MODULARITY

[0117] Fig. 7 A shows a perspective view of a cushion of a patient interface configured to be worn by a patient and convey pressurized air to the patient’s nose and the patient’s mouth.

[0118] Fig. 7B shows a perspective view of a cushion of a patient interface configured to be worn by a patient and convey pressurized air to the patient’s nose.

[0119] Fig. 7C shows a perspective view of tubes usable with either the cushion of Fig. 7 A or the cushion of Fig. 7B.A2578192 12.0 21Ref: P2755WO1 / 506986PCT1

[0120] Fig. 7D shows a perspective view of rigidiser arms usable with either the cushion of Fig. 7 A of the cushion of Fig. 7B.

[0121] Fig. 7E shows a perspective view of headgear straps usable with the cushion of Fig. 7 A.

[0122] Fig. 7F shows a perspective view of headgear straps usable with the cushion of Fig. 7B.

[0123] Fig. 7G shows a front view of a pair of sleeves that is removably fitted to either the tubes of Fig. 7C or the rigidiser arms of Fig. 7D.

[0124] Fig. 7H shows a front view of a full sleeve that is removably fitted to the rigidiser arms of Fig. 7D.

[0125] Fig. 71 shows a front perspective view of yet another alternate form of a full sleeve that is removably fitted to the rigidiser arms of Fig. 7D.

[0126] Fig. 7J is a front view of a patient wearing the cushion of Fig. 7A connected to the tubes of Fig. 7C, the headgear straps of Fig. 7E, and the sleeves of Fig. 7G.

[0127] Fig. 7K is a front view of a patient wearing the cushion of Fig. 7A connected to the rigidiser arms of Fig. 7D, the headgear straps of Fig. 7E, and the sleeve of Fig. 7H.

[0128] Fig. 7L is a front view of a patient wearing the cushion of Fig. 7B connected to the conduit headgear of Fig. 7C, and the headgear straps of Fig. 7F.

[0129] Fig. 7M is a front view of a patient wearing the cushion of Fig. 7B connected to the rigi disier arms of Fig. 7D, the headgear straps of Fig. 7F, and the sleeve of Fig. 71.

[0130] Fig. 7N is an isolated perspective view of the vent of Fig. 7L.

[0131] Fig. 70 is an isolated perspective view of a portion of the air circuit of Fig. 7M.

[0132] Fig. 7P is a schematic view illustrating the possible combinations of the patient interfaces.3.5 DECOUPLING STRUCTURES

[0133] Fig. 8A shows a perspective view of a patient interface with a decoupling structure in accordance with one aspect of the invention..

[0134] Fig. 8B shows a cross-sectional view of the patient interface of Fig. 8 A.

[0135] Fig. 8C shows a detail view of the decoupling structure of Figs. 8A and 8B.A2578192 12.0Ref: P2755WO1 / 506986PCT13.6 FURTHER EXAMPLES OF PATIENT INTERFACES

[0136] Figs. 9A-9D show views of a patient interface according to another example of the present technology.

[0137] Figs. 10A-10F show views of a cushion module of the patient interface shown in Figs. 9A-9D.

[0138] Fig. 11 shows a posterosuperior view of the cushion module shown in Figs. 10A-10F.

[0139] Figs. 12A-12C show views of a frame of the patient interface shown in Figs. 9A-9D.

[0140] Figs. 13A shows a cross-section view through an arm of the frame at the location indicated in Fig. 12A.

[0141] Figs. 13B-13D show three examples of the pads suitable for the frame shown in Figs. 12A-12C.

[0142] Figs. 14A-14B show views of a patient interface according to another example of the present technology.

[0143] Fig. 15 shows a posterior view of the seal-forming structure of the cushion module shown in Figs. 10A-10F with some regions delineated by broken lines.4 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

[0144] Before the present technology is described in further detail, it is to be understood that the technology is not limited to the particular examples described herein, which may vary. It is also to be understood that the terminology used in this disclosure is for the purpose of describing only the particular examples discussed herein, and is not intended to be limiting.

[0145] 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.A2578192 12.0 23Ref: P2755WO1 / 506986PCT14.1 THERAPY

[0146] In one form, the present technology comprises a method for treating a respiratory disorder comprising applying positive pressure to the entrance of the airways of a patient 1000.

[0147] In certain examples of the present technology, a supply of air at positive pressure is provided to the nasal passages of the patient via one or both nares.

[0148] In certain examples of the present technology, mouth breathing is limited, restricted or prevented.4.2 RESPIRATORY THERAPY SYSTEMS

[0149] In one form, the present technology comprises a respiratory therapy system for treating a respiratory disorder. The respiratory therapy system may comprise an RPT device 4000 for supplying a flow of air to the patient 1000 via an air circuit 4170 and a patient interface 3000.4.3 PATIENT INTERFACE

[0150] A non-invasive patient interface 3000, such as that shown in Fig. 3A, in accordance with one aspect of the present technology comprises the following functional aspects: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300, a vent 3400, one form of connection port 3600 for connection to air circuit 4170, and a forehead support 3700. In some forms a functional aspect may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use the seal -forming structure 3100 is arranged to surround an entrance to the airways of the patient so as to maintain positive pressure at the entrance(s) to the airways of the patient 1000. The sealed patient interface 3000 is therefore suitable for delivery of positive pressure therapy.

[0151] As shown in Fig. 6, a non-invasive patient interface 3000 in accordance with another aspect of the present technology comprises the following functional aspects: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300, a vent 3400 and one form of connection port 3600 for connection to an air circuit (such as the air circuit 4170 shown in Figs. 1 A-1C). The plenum chamber 3200 may be formed of one or more modular components (e.g., a cushion module 3150 together with the seal -forming structure 3100) in the sense that it or they can be replaced with different components, for example components of a different size.A2578192 12.0 24Ref: P2755WO1 / 506986PCT1

[0152] If a patient interface is unable to comfortably deliver a minimum level of positive pressure to the airways, the patient interface may be unsuitable for respiratory pressure therapy.

[0153] The patient interface 3000 in accordance with one form of the present technology is constructed and arranged to be able to provide a supply of air at a positive pressure above the ambient, for example at least 2, 4, 6, 10, or 20 cmH20 with respect to ambient.4.3.1 Seal-forming structure

[0154] In one form of the present technology, a seal-forming structure 3100 provides a target seal-forming region, and may additionally provide a cushioning function. The target seal-forming region is a region on the seal -forming structure 3100 where sealing may occur. The region where sealing actually occurs- the actual sealing surface- may change within a given treatment session, from day to day, and from patient to patient, depending on a range of factors including for example, where the patient interface was placed on the face, tension in the positioning and stabilising structure and the shape of a patient’s face.

[0155] In one form the target seal -forming region is located on an outside surface of the seal-forming structure 3100.

[0156] In certain forms of the present technology, the seal-forming structure 3100 is constructed from a biocompatible material, e.g. silicone rubber.

[0157] A seal -forming structure 3100 in accordance with the present technology may be constructed from a soft, flexible, resilient material such as silicone.

[0158] In certain forms of the present technology, a system is provided comprising more than one a seal-forming structure 3100, each being configured to correspond to a different size and / or shape range. For example the system may comprise one form of a seal-forming structure 3100 suitable for a large sized head, but not a small sized head and another suitable for a small sized head, but not a large sized head.4.3.1.1 Sealing mechanisms

[0159] In one form, the seal -forming structure includes a sealing flange utilizing a pressure assisted sealing mechanism. In use, the sealing flange can readily respond to a system positive pressure in the interior of the plenum chamber 3200 acting on its underside to urge it into tight sealing engagement with the face. The pressure assistedA2578192 12.0 25Ref: P2755WO1 / 506986PCT1mechanism may act in conjunction with elastic tension in the positioning and stabilising structure.

[0160] In one form, the seal -forming structure 3100 comprises a sealing flange and a support flange. The sealing flange comprises a relatively thin member with a thickness of less than about 1mm, for example about 0.25mm to about 0.45mm, which extends around the perimeter of the plenum chamber 3200. Support flange may be relatively thicker than the sealing flange. The support flange is disposed between the sealing flange and the marginal edge of the plenum chamber 3200, and extends at least part of the way around the perimeter. The support flange is or includes a springlike element and functions to support the sealing flange from buckling in use.

[0161] In one form, the seal-forming structure may comprise a compression sealing portion or a gasket sealing portion. In use the compression sealing portion, or the gasket sealing portion is constructed and arranged to be in compression, e.g. as a result of elastic tension in the positioning and stabilising structure.

[0162] In one form, the seal -forming structure comprises a tension portion. In use, the tension portion is held in tension, e.g. by adjacent regions of the sealing flange.

[0163] In one form, the seal-forming structure comprises a region having a tacky or adhesive surface.

[0164] In certain forms of the present technology, a seal -forming structure may comprise one or more of a pressure-assisted sealing flange, a compression sealing portion, a gasket sealing portion, a tension portion, and a portion having a tacky or adhesive surface.4.3.1.2 Nose bridge or nose ridge region

[0165] In one form, the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on a nose bridge region or on a nose-ridge region of the patient's face.

[0166] In one form, the seal -forming structure includes a saddle-shaped region constructed to form a seal in use on a nose bridge region or on a nose-ridge region of the patient's face.4.3.1.3 Upper lip region

[0167] In one form, the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on an upper lip region (that is, the lip superior) of the patient's face.A2578192 12.0 26Ref: P2755WO1 / 506986PCT1

[0168] In one form, the seal -forming structure includes a saddle-shaped region constructed to form a seal in use on an upper lip region of the patient's face.4.3.1.4 Chin-region

[0169] In one form the non-invasive patient interface 3000 comprises a sealforming structure that forms a seal in use on a chin-region of the patient's face.

[0170] In one form, the seal -forming structure includes a saddle-shaped region constructed to form a seal in use on a chin-region of the patient's face.4.3.1.5 Forehead region

[0171] In one form, the seal-forming structure that forms a seal in use on a forehead region of the patient's face. In such a form, the plenum chamber may cover the eyes in use.4.3.1.6 Nasal pillows

[0172] In one form the seal-forming structure of the non-invasive patient interface 3000 comprises a pair of nasal puffs, or nasal pillows, each nasal puff or nasal pillow being constructed and arranged to form a seal with a respective naris of the nose of a patient.

[0173] Nasal pillows in accordance with an aspect of the present technology include: a frusto-cone, at least a portion of which forms a seal on an underside of the patient's nose, a stalk, a flexible region on the underside of the frusto-cone and connecting the frusto-cone to the stalk. In addition, the structure to which the nasal pillow of the present technology is connected includes a flexible region adjacent the base of the stalk. The flexible regions can act in concert to facilitate a universal joint structure that is accommodating of relative movement both displacement and angular of the frusto-cone and the structure to which the nasal pillow is connected. For example, the frusto-cone may be axially displaced towards the structure to which the stalk is connected.4.3.1.7 Nose-only Masks

[0174] In one form, the patient interface 3000 comprises a seal-forming structure 3100 configured to seal around an entrance to the patient’s nasal airways but not around the patient’s mouth. The seal -forming structure 3100 may be configured to seal to the patient’s lip superior. The patient interface 3000 may leave the patient’s mouth uncovered. This patient interface 3000 may deliver a supply of air or breathable gas to both nares of patient 1000 and not to the mouth. This type of patient interface may be identified as a nose-only mask.A2578192 12.0 27Ref: P2755WO1 / 506986PCT1

[0175] One form of nose-only mask according to the present technology is what has traditionally been identified as a “nasal mask”, having a seal-forming structure 3100 configured to seal on the patient’s face around the nose and over the bridge of the nose. A nasal mask may be generally triangular in shape. In one form, the non-invasive patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use to an upper lip region (e.g. the lip superior), to the patient’s nose bridge or at least a portion of the nose ridge above the pronasale, and to the patient's face on each lateral side of the patient’s nose, for example proximate the patient’s nasolabial sulci. The patient interface 3000 shown in Fig. IB has this type of seal-forming structure 3100. This patient interface 3000 may deliver a supply of air or breathable gas to both nares of patient 1000 through a single orifice.

[0176] Another form of nose-only mask may seal around an inferior periphery of the patient’s nose without engaging the user’s nasal ridge. This type of patient interface 3000 may be identified as a “nasal cradle” mask and the seal-forming structure 3100 may be identified as a “nasal cradle cushion”, for example. In one form, for example as shown in Fig. 6, the seal-forming structure 3100 is configured to form a seal in use with inferior surfaces of the nose around the nares. The sealforming structure 3100 may be configured to seal around the patient’s nares at an inferior periphery of the patient’s nose including to an inferior and / or anterior surface of a pronasale region of the patient’s nose and to the patient’s nasal alae. The sealforming structure 3100 may seal to the patient’s lip superior. The shape of the sealforming structure 3100 may be configured to match or closely follow the underside of the patient’s nose and may not contact a nasal bridge region of the patient’s nose or any portion of the patient’s nose superior to the pronasale. In one form of nasal cradle cushion, the seal-forming structure 3100 comprises a bridge portion dividing the opening into two orifices, each of which, in use, supplies air or breathable gas to a respective one of the patient’s nares. The bridge portion may be configured to contact or seal against the patient’s columella in use. Alternatively, the seal-forming structure 3100 may comprise a single opening to provide a flow or air or breathable gas to both of the patient’s nares.

[0177] In some forms, a nose-only mask may comprise nasal pillows, described above.A2578192 12.0 28Ref: P2755WO1 / 506986PCT14.3.1.8 Nose and Mouth Masks

[0178] In one form, the patient interface 3000 comprises a seal-forming structure 3100 configured to seal around an entrance to the patient’s nasal airways and also around the patient’s mouth. The seal -forming structure 3100 may be configured to seal to the patient’s face proximate a chin region. This patient interface 3000 may deliver a supply of air or breathable gas to both nares and to the mouth of patient 1000. This type of patient interface may be identified as a nose and mouth mask.

[0179] One form of nose-and-mouth mask according to the present technology is what has traditionally been identified as a “full-face mask”, having a seal-forming structure 3100 configured to seal on the patient’s face around the nose, below the mouth and over the bridge of the nose. A nose-and-mouth mask may be generally triangular in shape. In one form the patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use to a patient’s chin-region (which may include the patient’s lip inferior and / or a region directly inferior to the lip inferior), to the patient’s nose bridge or at least a portion of the nose ridge superior to the pronasale, and to cheek regions of the patient's face. The patient interface 3000 shown in Fig. 1C is of this type. This patient interface 3000 may deliver a supply of air or breathable gas to both nares and mouth of patient 1000 through a single orifice. This type of sealforming structure 3100 may be referred to as a “nose-and-mouth cushion”.

[0180] In another form the patient interface 3000 comprises a seal-forming structure 3100 that forms a seal in use on a patient’s chin region (which may include the patient’s lip inferior and / or a region directly inferior to the lip inferior), to an inferior and / or an anterior surface of a pronasale portion of the patient’s nose, to the alae of the patient’s nose and to the patient’s face on each lateral side of the patient’s nose, for example proximate the nasolabial sulci. The seal-forming structure 3100 may also form a seal against a patient’s lip superior. A patient interface 3000 having this type of seal-forming structure may have a single opening configured to deliver a flow of air or breathable gas to both nares and mouth of a patient, may have an oral hole configured to provide air or breathable gas to the mouth and a nasal hole configured to provide air or breathable gas to the nares, or may have an oral hole for delivering air to the patient’s mouth and two nasal holes for delivering air to respective nares. This type of patient interface 3000 may have a nasal portion and an oral portion, the nasal portion sealing to the patient’s face at similar locations to a nasal cradle mask.A2578192 12.0 29Ref: P2755WO1 / 506986PCT1

[0181] In a further form of nose and mouth mask, the patient interface 3000 may comprise a seal -forming structure 3100 having a nasal portion comprising nasal pillows and an oral portion configured to form a seal to the patient’s face around the patient’s mouth.

[0182] In some forms, the seal -forming structure 3100 may have a nasal portion that is separate and distinct from an oral portion. In other forms, a seal-forming structure 3100 may form a contiguous seal around the patient’s nose and mouth.

[0183] It is to be understood that the above examples of different forms of patient interface 3000 do not constitute an exhaustive list of possible configurations. In some forms a patient interface 3000 may comprise a combination of different features of the above described examples of nose-only and nose and mouth masks.4.3.2 Plenum chamber

[0184] The plenum chamber 3200 has a perimeter that is shaped to be complementary to the surface contour of the face of an average person in the region where a seal will form in use. In use, a marginal edge of the plenum chamber 3200 is positioned in close proximity to an adjacent surface of the face. Actual contact with the face is provided by the seal -forming structure 3100. The seal-forming structure 3100 may extend in use about the entire perimeter of the plenum chamber 3200. In some forms, the plenum chamber 3200 and the seal -forming structure 3100 are formed from a single homogeneous piece of material.

[0185] In certain forms of the present technology, the plenum chamber 3200 does not cover the eyes of the patient in use. In other words, the eyes are outside the pressurised volume defined by the plenum chamber. Such forms tend to be less obtrusive and / or more comfortable for the wearer, which can improve compliance with therapy.

[0186] In certain forms of the present technology, the plenum chamber 3200 is constructed from a transparent material, e.g. a transparent polycarbonate. The use of a transparent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy. The use of a transparent material can aid a clinician to observe how the patient interface is located and functioning.

[0187] In certain forms of the present technology, the plenum chamber 3200 is constructed from a translucent material. The use of a translucent material can reduce the obtrusiveness of the patient interface, and help improve compliance with therapy.A2578192 12.0 30Ref: P2755WO1 / 506986PCT1

[0188] In some forms, the plenum chamber 3200 is constructed from a rigid material such as polycarbonate. The rigid material may provide support to the sealforming structure.

[0189] In some forms, the plenum chamber 3200 is constructed from a flexible material (e.g., constructed from a soft, flexible, resilient material like silicone, textile, foam, etc.). For example, in examples then may be formed from a material which has a Young's modulus of 0.4 GPa or lower, for example foam. In some forms of the technology the plenum chamber 3200 may be made from a material having Young's modulus of 0.1 GPa or lower, for example rubber. In other forms of the technology the plenum chamber 3200 may be made from a material having a Young's modulus of 0.7MPa or less, for example between 0.7MPa and 0.3MPa. An example of such a material is silicone.4.3.2.1 Multiple Openings

[0190] As shown in Figs. 7A and 7B, different plenum chambers 3200-1, 3200-2 may be formed as part of a multi -opening cushion 3050-1, 3050-2. In the illustrated examples, the cushions 3050-1, 3050-2 each include three openings, although an alternate cushion may be formed with greater or fewer openings.

[0191] In some forms, the different openings may serve different functions. For example, some openings may be exclusively inlet openings, while other openings may be exclusively outlet openings.

[0192] In other forms, at least one opening may serve two different functions. For example, one opening may operate as both an inlet and an outlet during the same breathing cycle.

[0193] The plurality of openings may allow for a variety of configurations of air delivery to the plenum chamber 3200-1, 3200-2. For example, depending on patient need and / or patient comfort, the patient may use a given cushion 3050-1, 3050-2 in a “tube-up” configuration (e.g., using conduit headgear - described below) or a “tubedown” configuration (e.g., using a single conduit in front of the patient’s face).4.3.2.1.1 Nose and Mouth Mask

[0194] As shown in Fig. 7A, the plenum chamber 3200-1 includes a pair of plenum chamber inlet ports 3254-1, which may be used to convey gas into and / or out of the plenum chamber 3200-1. The plenum chamber inlet ports 3254-1 may be disposed on opposite sides (e.g., left and right sides) of the plenum chamber 3200-1.A2578192 12.0 31Ref: P2755WO1 / 506986PCT1

[0195] In some forms, the plenum chamber 3200-1 may also include at least one vent opening 3402-1 (see e.g., Fig. 7A). The vent opening 3402-1 may be disposed in a centre of the plenum chamber 3200-1. For example, the vent opening 3402-1 may be disposed between the plenum chamber inlet ports 3254-1.

[0196] In some forms, the plenum chamber 3200-1 may include a pair of grooves 3266-1. Each groove 3266-1 may be disposed proximate to one of the plenum chamber inlet ports 3254-1. Each groove 3266-1 may form a partially recessed surface.4.3.2.1.2 Nose-only Mask

[0197] The plenum chamber 3200-2 of a nasal only cushion 3050-2 may be similar to the plenum chamber 3200-1 of the mouth and nose cushion 3050-1. Only some similarities and differences between the plenum chambers 3200-1, 3200-2 may be described below.

[0198] As shown in Fig. 7B, the plenum chamber 3200-2 includes a pair of plenum chamber inlet ports 3254-2, which may be used to convey gas into and / or out of the plenum chamber 3200-2. The plenum chamber inlet ports 3254-2 may be disposed on opposite sides (e.g., left and right sides) of the plenum chamber 3200-2.

[0199] In some forms, the plenum chamber 3200-2 may also include at least one vent opening 3402-2 (see e.g., Fig. 7B). The vent opening 3402-2 may be disposed in a centre of the plenum chamber 3200-2. For example, the vent opening 3402-2 may be disposed between the plenum chamber inlet ports 3254-2.

[0200] In some forms, the plenum chamber 3200-2 may include a pair of grooves 3266-2. Each groove 3266-2 may be disposed proximate to one of the plenum chamber inlet ports 3254-2. Each groove 3266-2 may form a partially recessed surface.4.3.3 Positioning and stabilising structure

[0201] The seal-forming structure 3100 of the patient interface 3000 of the present technology may be held in sealing position in use by the positioning and stabilising structure 3300. The positioning and stabilising structure 3300 may comprise and function as “headgear” since it engages the patient’s head in order to hold the patient interface 3000 in a sealing position. Examples of positioning and stabilising structures are shown in Figs. 3A and 14A-14B.A2578192 12.0 32Ref: P2755WO1 / 506986PCT1

[0202] In one form the positioning and stabilising structure 3300 provides a retention force at least sufficient to overcome the effect of the positive pressure in the plenum chamber 3200 to lift off the face.

[0203] In one form the positioning and stabilising structure 3300 provides a retention force to overcome the effect of the gravitational force on the patient interface 3000.

[0204] In one form the positioning and stabilising structure 3300 provides a retention force as a safety margin to overcome the potential effect of disrupting forces on the patient interface 3000, such as from tube drag, or accidental interference with the patient interface.

[0205] In one form of the present technology, a positioning and stabilising structure 3300 is provided that is configured in a manner consistent with being worn by a patient while sleeping. In one example the positioning and stabilising structure 3300 has a low profile, or cross-sectional thickness, to reduce the perceived or actual bulk of the apparatus. In one example, the positioning and stabilising structure 3300 comprises at least one strap having a rectangular cross-section. In one example the positioning and stabilising structure 3300 comprises at least one flat strap.

[0206] In one form of the present technology, a positioning and stabilising structure 3300 is provided that is configured so as not to be too large and bulky to prevent the patient from lying in a supine sleeping position with a back region of the patient’s head on a pillow.

[0207] In one form of the present technology, a positioning and stabilising structure 3300 is provided that is configured so as not to be too large and bulky to prevent the patient from lying in a side sleeping position with a side region of the patient’s head on a pillow.

[0208] In one form of the present technology, a positioning and stabilising structure 3300 is provided with a decoupling portion located between an anterior portion of the positioning and stabilising structure 3300, and a posterior portion of the positioning and stabilising structure 3300. The decoupling portion does not resist compression and may be, e.g. a flexible or floppy strap. The decoupling portion is constructed and arranged so that when the patient lies with their head on a pillow, the presence of the decoupling portion prevents a force on the posterior portion from being transmitted along the positioning and stabilising structure 3300 and disrupting the seal.A2578192 12.0 33Ref: P2755WO1 / 506986PCT1

[0209] In one form of the present technology, a positioning and stabilising structure 3300 comprises a strap constructed from a laminate of a fabric patientcontacting layer, a foam inner layer and a fabric outer layer. In one form, the foam is porous to allow moisture, (e.g., sweat), to pass through the strap. In one form, the fabric outer layer comprises loop material to engage with a hook material portion.

[0210] In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap that is extensible, e.g. resiliently extensible. For example the strap may be configured in use to be in tension, and to direct a force to draw a seal-forming structure into sealing contact with a portion of a patient’s face. In an example the strap may be configured as a tie.

[0211] In one form of the present technology, the positioning and stabilising structure comprises a first tie, the first tie being constructed and arranged so that in use at least a portion of an inferior edge thereof passes superior to an otobasion superior of the patient’s head and overlays a portion of a parietal bone without overlaying the occipital bone.

[0212] In one form of the present technology suitable for a nasal-only mask or for a full-face mask, the positioning and stabilising structure includes a second tie, the second tie being constructed and arranged so that in use at least a portion of a superior edge thereof passes inferior to an otobasion inferior of the patient’s head and overlays or lies inferior to the occipital bone of the patient’s head.

[0213] In one form of the present technology suitable for a nasal-only mask or for a full-face mask, the positioning and stabilising structure includes a third tie that is constructed and arranged to interconnect the first tie and the second tie to reduce a tendency of the first tie and the second tie to move apart from one another.

[0214] In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap that is bendable and e.g. non-rigid. An advantage of this aspect is that the strap is more comfortable for a patient to lie upon while the patient is sleeping.

[0215] In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap constructed to be breathable to allow moisture vapour to be transmitted through the strap,

[0216] In certain forms of the present technology, a system is provided comprising more than one positioning and stabilising structure 3300, each being configured to provide a retaining force to correspond to a different size and / or shapeA2578192 12.0 34Ref: P2755WO1 / 506986PCT1range. For example the system may comprise one form of positioning and stabilising structure 3300 suitable for a large sized head, but not a small sized head, and another, suitable for a small sized head, but not a large sized head.4.3.3.1 Conduit headgear4.3.3.1.1 Conduit headgear tubes

[0217] In some forms of the present technology, the positioning and stabilising structure 3300 comprises one or more headgear tubes 3350 that deliver pressurised air received from a conduit forming part of the air circuit 4170 from the RPT device to the patient’s airways, for example through the plenum chamber 3200 and sealforming structure 3100. In the form of the present technology illustrated in Fig. 6, the positioning and stabilising structure 3300 comprises two tubes 3350 that deliver air to the plenum chamber 3200 from the air circuit 4170. The tubes 3350 are configured to position and stabilise the seal-forming structure 3100 of the patient interface 3000 at the appropriate part of the patient’s face (for example, the nose and / or mouth) in use. This allows the conduit of air circuit 4170 providing the flow of pressurised air to connect to a connection port 3600 of the patient interface in a position other than in front of the patient’s face, for example on top of the patient’s head.

[0218] In the form of the present technology illustrated in Fig. 6, the positioning and stabilising structure 3300 comprises two tubes 3350, each tube 3350 being positioned in use on a different side of the patient’s head and extending across the respective cheek region, above the respective ear (superior to the otobasion superior on the patient’s head) to a decoupling structure in the form of a swivel elbow 3610 on top of the head of the patient 1000. This form of technology may be advantageous because, if a patient sleeps with their head on its side and one of the tubes 3350 is compressed to block or partially block the flow of gas along the tube 3350, the other tube 3350 remains open to supply pressurised gas to the patient. In other examples of the technology, the patient interface 3000 may comprise a different number of tubes, for example one tube, or two or more tubes.

[0219] In the form of the technology shown in Fig. 6, the two tubes 3350 are fluidly connected at superior ends to each other and to the connection port 3600. In some examples, the two tubes 3350 are integrally formed while in other examples the tubes 3350 are formed separately but are connected in use and may be disconnected, for example for cleaning or storage. Where separate tubes are used, they may be indirectly connected together, for example each may be connected to a T-shapedA2578192 12.0 35Ref: P2755WO1 / 506986PCT1connector. The T-shaped connector may have two arms / branches each fluidly connectable to a respective one of the tubes 3350. Additionally, the T-shaped connector may have a third arm or opening providing the connection port 3600 for fluid connection to the air circuit 4170 in use. The opening may be an inlet 3332 (see e.g., 7C) for receiving the flow of pressurized air.

[0220] The tubes 3350 may be formed from a flexible material, such as an elastomer, e.g. silicone or TPE, and / or from one or more textile and / or foam materials. The tubes 3350 may have a preformed shape and may be able to be bent or moved into another shape upon application of a force but may return to the original preformed shape in the absence of said force. The tubes 3350 may be generally arcuate or curved in a shape approximating the contours of a patient’s head between the top of the head and the nasal or oral region.

[0221] Each tube 3350 may be configured to receive a flow of air from the connection port 3600 on top of the patient’s head and to deliver the flow of air to the seal-forming structure 3100 at the entrance of the patient’s airways. In the example shown in Fig. 6, each tube 3350 lies in use on a path extending from the plenum chamber 3200 across the patient’s cheek region and superior to the patient’s ear to the elbow 3610. For example, a portion of each tube 3350 proximate the plenum chamber 3200 may overlie a maxilla region of the patient’s head in use. Another portion of each tube 3350 may overlie a region of the patient’s head superior to an otobasion superior of the patient’s head. Each of the tubes 3350 may also lie over the patient’s sphenoid bone and / or temporal bone and either or both of the patient’s frontal bone and parietal bone. The elbow 3610 may be located in use over the patient’s parietal bone, over the frontal bone and / or over the junction therebetween (e.g. the coronal suture).4.3.3.1.2 Conduit headgear connection port

[0222] In certain forms of the present technology, the patient interface 3000 may comprise a connection port 3600 located proximal to a superior, lateral or posterior portion of a patient’s head. For example, in the form of the present technology illustrated in Fig 6, the connection port 3600 is located on top of the patient’s head (e.g. at a superior location with respect to the patient’s head). In this example the patient interface 3000 comprises a decoupling structure in the form of elbow 3610 forming the connection port 3600. The elbow 3610 may be configured to fluidly connect with a conduit of an air circuit 4170. The elbow 3610 may be configured toA2578192 12.0 36Ref: P2755WO1 / 506986PCT1swivel with respect to the positioning and stabilising structure 3300 to at least partially decouple the conduit from the positioning and stabilising structure 3300. In some examples the elbow 3610 may be configured to swivel by rotation about a substantially vertical axis and, in some particular examples, by rotation about two or more axes. In some examples the elbow may comprise or be connected to the tubes 3350 by a ball-and-socket joint. The connection portion 3600 may be located in the sagittal plane of the patient’s head in use.4.3.3.1 Headgear straps

[0223] In some forms, the positioning and stabilising structure 3300 may include headgear 3302 with at least one strap which may be worn by the patient in order to assist in properly orienting the seal -forming structure 3100 against the patient’s face (e.g., in order to limit or prevent leaks).

[0224] As described above, some forms of the headgear 3302 may be constructed from a textile material, which may be comfortable against the patient’s skin. The textile may be flexible in order to conform to a variety of facial contours. Although the textile may include rigidisers along a selected length, which may limit bending, flexing, and / or stretching of the headgear 3302.

[0225] In certain forms, the headgear 3302 may be at least partially extensible. For example, the headgear 3302 may include elastic, or a similar extensible material. For example, the entire headgear 3302 may be extensible or selected portions may be extensible (or more extensible than surrounding portions). This may allow the headgear 3302 to stretch while under tension, which may assist in providing a sealing force for the seal -forming structure 3100.

[0226] Two forms of the headgear, four-point headgear 3302-1 and two-point headgear 3302-2, are discussed in more detail below as illustrative examples.4.3.3.2.1 Four-point connection

[0227] As shown in Fig. 7E, some forms of the headgear 3302-1 may be a four-point connection headgear. This means that the headgear 3302-1 may connect to four separate places on the plenum chamber 3200, on a frame connected to the plenum chamber 3200, and / or on arms connected to the plenum chamber 3200. The headgear 3302-1 may include four different straps providing a tensile force to help maintain the seal-forming structure 3100 in a sealing position. The positioning and stabilising structure 3300 of Fig. 3 A may also be considered a four-point connection headgear.A2578192 12.0 37Ref: P2755WO1 / 506986PCT1

[0228] In some forms, the headgear 3302-1 may include inferior straps 3304-1, which may connect to an inferior portion of the cushion 3050-1. The inferior straps 3304-1 may extend along the patient’s cheek toward a posterior region of the patient’s head. For example, the inferior straps 3304-1 may overlay the masseter muscle on either side of the patient’s face. The inferior straps 3304-1 may therefore contact the patient’s head below the patient’s ears. The inferior straps 3304-1 may meet at the posterior of the patient’s head, and may overlay the occipital bone and / or the trapezius muscle.

[0229] The headgear 3302-1 may also include superior straps 3305-1, which may overlay the temporal bones, parietal bone, and / or occipital bone. The superior straps 3305-1 may also connect to the tubes 3350 (e.g., by interfacing with the tabs 3320).

[0230] A rear strap 3307-1 may extend between the superior straps 3305-1 and between the inferior straps 3304-1. The inferior and superior straps 3304-1, 3305-1 on a given side (e.g., left or right) may also be connected to the rear strap 3307-1 adjacent to one another. The height of the rear strap 3307-1 may therefore be approximately the combined height of the inferior and superior strap 3304-1, 3305-1. The rear strap 3307-1 may overlay the occipital bone and / or the pariental bone in use. This may allow the rear strap 3307-1 to assist in anchoring the headgear 3302-1 to the patient’s head.

[0231] In the illustrated example, the headgear 3302-1 may be formed with a substantially X-shape. The inferior and superior straps 3304-1, 3305-1 may be connected to a rear strap 3307-1 using stitching, ultrasonic welding, or any similar process.

[0232] In some forms, the inferior straps 3304-1 are connected to a magnetic member 3306-1. For example, each inferior straps 3304-1 may be threaded through a magnetic member 3306-1, so that a length of each inferior strap 3304-1 may be adjusted. The magnetic members 3306-1 may removably connect to the magnets 3370-1 (described below), so that the inferior straps 3304-1 may be disconnected from the plenum chamber 3200, but the length of the inferior straps 3304-1 may not be affected.

[0233] In some forms, the superior straps 3305-1 may be connected directly to the tabs 3320 of the tubes 3350. The superior straps 3305-1 may be threaded through the tabs 3320 in order to adjust the length and control the tensile force of each superior strap 3305-1.A2578192 12.0 38Ref: P2755WO1 / 506986PCT1

[0234] In some forms, the headgear 3302-1 may be used only with the nose and mouth cushion 3050-1 (e.g., because the nose-only cushion 3050-1 does not have four connection points). However, the headgear 3302-1 may be used interchangeably with the tubes 3350 and the rigidiser arms 3340.4.3.3.2.2 Two-point connection

[0235] As shown in Fig. 7F, some forms of the headgear 3302-2 may be a two-point connection headgear. This means that the headgear 3302-2 may connect to two separate places.

[0236] In some forms, the headgear 3302-2 may be formed from a continuous piece of material. In other words, the headgear 3302-2 may not be formed from multiple straps connected (e.g., stitched) together. This may be comfortable for a patient as they will not be in contact with any seams or joints connecting different straps. In other forms, the headgear 3302-2 may be formed from multiple straps (e.g., two superior straps, a rear strap, etc.) that are connected together (e.g., with stitching, ultra-sonic welding, etc.).

[0237] In certain forms of the present technology, the positioning and stabilising structure 3300 comprises at least one headgear strap acting in addition to the tubes 3350 to position and stabilise the seal-forming structure 3100 at the entrance to the patient’s airways. As shown in Fig. 6, the patient interface 3000 comprises a strap 3307-2 forming part of the positioning and stabilising structure 3300. The strap 3307-2 may be known as a back strap or a rear headgear strap, for example. The rear strap 3307-2 may overlay the temporal bones, parietal bone, and / or occipital bone. In other examples of the present technology, one or more further straps may be provided. For example, patient interfaces 3000 according to examples of the present technology having a nose-and-mouth cushion may have a second, lower, strap configured to lie against the patient’s head proximate the patient’s neck and / or against posterior surfaces of the patient’s neck.

[0238] In the example shown in Fig. 6, strap 3310 of the positioning and stabilising structure 3300 is connected between the two tubes 3350 positioned on each side of the patient’s head and passing around the back of the patient’s head, for example overlying or lying inferior to the occipital bone of the patient’s head in use. The strap 3310 connects to each tube above the patient’s ears. With reference to Fig.6, the positioning and stabilising structure 3300 comprises a pair of tabs 3320. In use a strap 3310 may be connected between the tabs 3320. The strap 3310 may beA2578192 12.0 39Ref: P2755WO1 / 506986PCT1sufficiently flexible to pass around the back of the patient’s head and lie comfortably against the patient’s head, even when under tension in use.

[0239] As shown in Fig. 7F, some forms of the headgear 3302-2 may be at least partially bifurcated. For example, a rear strap 3307-2 of the headgear 3302-2 (e.g., configured to contact the posterior portion of the patient’s head) may be wider than the surrounding portions of the headgear 3302-2. An intermediate section 3308-2 of the rear strap 3307-2 may include a slit 3309-2. A superior section of the rear strap 3307-2 may therefore be movable relative to the inferior section as a result of the slit 3309-2. This may allow the patient to have a larger strap coverage on the posterior region of their head, which may assist in better anchoring the headgear 3302-2 to the patient’s head since there is no inferior strap (e.g., 3304-1).

[0240] In some forms, the headgear 3302-2 may be used only with the nasal cushion 3050-2 (e.g., because the nose and mouth cushion 3050-1 does not have four connection points). However, the headgear 3302-2 may be used interchangeably with the tubes 3350 and the rigidiser arms 3340.4.3.3.3 Rigidiser Arm

[0241] As shown in Fig. 7D, a rigidiser arm 3340 may be an elongated, rigid member that assists in maintaining the cushion (e.g., the nose and mouth cushion 3050-1 or the nasal cushion 3050-2) in an operating position. The rigidiser arm 3340 may contact a side of the patient’s head and provide a force to limit slipping of the seal-forming structure 3100 from the patient’s nose and / or mouth.

[0242] In some forms, the rigidiser arm 3340 is constructed from a rigid material (e.g., plastic). The rigid material may not permit the rigidiser arm 3340 to stretch. Additionally, the rigidiser arm 3340 may be substantially inflexible and may be unable to bend. The rigidiser arm 3340 may be pre-molded into a desired shape in order to fit a patient’s head. For example, the rigidiser arms 3340 may be molded with a curved shape to substantially correspond to the shape of the side of the patient’s head (e.g., overlaying the masseter muscle and / or the temporal bone).

[0243] In certain forms, the rigidiser arm 3340 may be molded in order to conform to a specific patient’s head (e.g., the rigidiser arm 3340 is customized).

[0244] In some forms, the rigidiser arm 3340 may be flexible along at least one direction. For example, the rigidiser arm 3340 may be flexible about its width and may be inflexible along its length. In other words, the rigidiser arm 3340 may be bendable about an axis along the width of the rigidiser arm 3340, but may be unableA2578192 12.0 40Ref: P2755WO1 / 506986PCT1to bend about an axis perpendicular to the rigidiser arm 3340. This may allow an individual patient to adjust the rigidiser arm 3340 in order to better fit their individual head.

[0245] In certain forms, the rigidiser arm 3340 may remain in the new position after being bent. This may allow a patient adjust the shape of the rigidiser arm 3340 for their specific head and then the rigidiser arm 3340 will keep the desired shape while in use in order to promote patient comfort.

[0246] In some forms, a first end 3342 of the rigidiser arm 3340 may be a free end and a second end 3344 (e.g., opposite of the first end 3342) of the rigidiser arm 3340 may be fixed. The first end 3342 may be curved in order to minimize sharp edges that could cause patient discomfort. The first end 3342 may also overlay the patient’s head proximate to the temporal bone, in use. The second end 3344 may be fixed to an arm connection structure 3504.

[0247] In some forms, the arm connection structure 3504 may be similar to the conduit connection structure 3500. For example, the arm connection structure 3504 and the conduit connection structure 3500 may have substantially the same shape. This may allow either the conduit connection structure 3500 or the arm connection structure 3504 to fit into the groove (e.g., 3266-1 or 3266-2) and connect to the plenum chamber inlet port 3254. The arm connection structure 3504 may connect to the nose and mouth cushion 3050-1 or the nose-only cushion 3050-2 in substantially the same way as the conduit connection structure 3500 (e.g., via a snap fit, press fit, friction fit, etc.).

[0248] In some forms, the arm connection structure 3504 may act as a plug for the plenum chamber inlet port 3254 (e.g., either 3254-1 and / or 3254-2). Unlike the tubes 3350, the rigidiser arm 3340 does not convey pressurized air to the plenum chamber 3200. The rigidised arm 3340 may be used with a “tube down” configuration, where a hose is connected to the vent opening 3402 (e.g., either 3402-1 and / or 3402-2), and conveys air into the plenum chamber 3200 through the vent opening 3402. In this example, air does not need to travel into or out of the plenum chamber inlet openings 3254. Thus, the arm connection structure 3504 may form a seal with the plenum chamber inlet opening 3254 in order to limit airflow into or out of the plenum chamber 3200.A2578192 12.0 41Ref: P2755WO1 / 506986PCT14.3.4 Vent

[0249] In one form, the patient interface 3000 includes a vent 3400 constructed and arranged to allow for the washout of exhaled gases, e.g. carbon dioxide.

[0250] In certain forms the vent 3400 is configured to allow a continuous vent flow from an interior of the plenum chamber 3200 to ambient whilst the pressure within the plenum chamber is positive with respect to ambient. The vent 3400 is configured such that the vent flow rate has a magnitude sufficient to reduce rebreathing of exhaled CO2 by the patient while maintaining the therapeutic pressure in the plenum chamber in use.

[0251] The vent 3400 is preferably located proximal to the patient interface to assist with the washout of carbon dioxide to prevent or otherwise limit CO2 rebreathing by the patient 1000 in use. For example, the vent 3400 may be located in or at least communicative with the plenum chamber 3200.

[0252] Alternatively, the vent 3400 is located in a decoupling structure, e.g., a swivel, elbow joint or ball and socket of the patient interface, as will be described further later in this specification.

[0253] One form of vent 3400 comprises a plurality of holes, for example, about 20 to about 80 holes, or about 40 to about 60 holes, or about 45 to about 55 holes.

[0254] The vent 3400 as herein described may be used with either the mouth and nose plenum chamber 3200-1 (e.g., illustrated in Figs. 7A) or the nose-only plenum chamber 3200-2 (e.g., illustrated in Figs. 7B).

[0255] With continued reference to Fig. 7A, the vent 3400 may include a vent housing 3404, which may be configured to engage with the vent opening 3402. The vent housing 3404 may be constructed from a rigid material or a semi-rigid material. For example, the vent housing 3404 may be constructed from plastic, metal, or any similar material. The vent housing 3404 may add rigidity to the patient interface 3000 (e.g., to limit unwanted bending that may affect the position of the seal-forming structure 3100 on the patient’s face).

[0256] The vent housing 3404 may include an anterior surface 3408, a posterior surface 3412, and a groove 3416. The anterior surface 3408 faces away from the patient’s face in use, and may be positioned outside the pressurized volume of the plenum chamber 3200. The posterior surface 3412 is disposed opposite to the anterior surface 3408. In use, the posterior surface 3412 may face the patient and may beA2578192 12.0 42Ref: P2755WO1 / 506986PCT1disposed within the pressurized volume of the plenum chamber 3200. The groove 3416 may be formed between the anterior and posterior surfaces 3408, 3412. A portion of the plenum chamber 3200 may be received within the groove 3416 in order to retain the vent 3400 in position.4.3.5 Diffusers

[0257] As shown in Fig. 7N, in some forms, a diffuser 3448 may be used with the vent housing 3404. The diffuser 3448 may assist with limiting the decibel output from any of the patient interface 3000 (or any other patient interface). Specifically, the diffuser 3448 may assist in limiting the decibel level associated with air output from the patient interface 3000 (e.g., exhaled air / washout gases), although the diffuser 3448 may limit the decibel level of at any point in the patient interface.

[0258] In certain forms, the diffuser 3448 may diffuse, and therefore slow, the washout gas exiting the plenum chamber 3200 and passing through the vent housing 3404. The diffuser 3448 may assist in avoiding jetting and associated discomfort to the patient and / or bed partner (e.g., noise caused by jetting against a pillow, sheets, bedclothes, etc.).

[0259] In some forms, the diffuser 3448 may include an anterior surface 3456 that faces away from the patient in use. An outer diameter of the anterior surface 3456 may be less than an inner diameter of the vent housing 3404 proximate to the anterior surface 3408. This may form a gap 3464 through which air may travel.

[0260] The diffuser 3448 may be constructed from any suitable material familiar to those skilled in the art such as an open-celled foam, fabric, wool, polymers or felts. For example, the diffuser may be constructed of a silicone or polyurethane foam. In some examples of the technology, it is important for the diffuser material to meet certain bio-compatibility requirements, to ensure that it is safe to breathe through, and there is a low risk of harm if any particles were to enter the airways of the patient in use.4.3.6 Decoupling structure(s)

[0261] In one form, such as the example of Fig. 8A, the patient interface 3000 includes at least one decoupling structure 3610, for example, a swivel or an elbow joint or a ball and socket, which receives the air circuit 4170. In Fig. 8 A, the patient interface 3000 is in the form of a nasal cushion mask 3000. However, it should beA2578192 12.0 43Ref: P2755WO1 / 506986PCT1understood that this is meant only by way of example, and the use of a decoupling structure 3610 as herein described with other forms of patient interfaces is envisaged.

[0262] The decoupling structure 3610 is constructed and arranged so that when the patient lies with their head on a pillow, its presence prevents or reduces a force on the air circuit (not shown), such as may arise due to its weight or when it drags across the patient’s bedding, from being transmitted to the positioning and stabilising structure 3300 and therefore to the seal-forming structure 3100 of the patient interface 3000. Such a transmission of force may disrupt the seal with the patient’s face.Essentially the decoupling structure 3610 acts to decouple forces from the air circuit 4170 and positioning and stabilising structure 3300 from the seal forming structure 3100.

[0263] The decoupling structure 3610, which may be formed from a suitably rigid and durable plastics material such as polycarbonate or the like, is configured or otherwise arranged in the form of a swivel elbow. It has a main body 3612 which is connected at a first end 3612A to the anterior side of a frame 3900 of the positioning and stabilising structure 3300. The main body 3612 is therefore fluidly connected to the plenum chamber 3200. The second end 3612B of the main body 3612 of the decoupling structure 3610 includes the connection port 3600, to which the downstream end of the air circuit (not shown) is connected in use. The second end 3612B is at an angle relative to the first end 3612A such that when the air circuit (not shown) is fitted, it extends away from the patient interface 3000 at a declined angle. This may reduce the force that may be applied, due to the weight of the air circuit (not shown), to the patient interface and may reduce the distance that the decoupling structure 3610 and attached air circuit 4170 projects away from the patient’s face. This configuration also means that the distance between the respective ends 3612A, 3612B on the superior side of the main body 3612 is greater than the distance between the respective ends 3612A, 3612B on the inferior side of the main body 3612.

[0264] As can be seen, the connection port 3600 is substantially concentrically arranged to the second end 3612B of the main body 3612 of the decoupling structure 3610. This creates a passage 3614 about the internal circumference of the main body 3612, the passage 3614 being formed by the internal surfaces of the main body 3612 and the opposing external surfaces of the connection port 3600 for a vent flow of gases to be vented from the patient interface 3000 in use. The passage 3614 forms a flow path for the vent flow of gases that is directed, initially at least, between theseA2578192 12.0 44Ref: P2755WO1 / 506986PCT1respective surfaces before being dispersed into ambient. This arrangement may better diffuse the washout gases and be less obtrusive for the patient.

[0265] The decoupling structure 3610 is shown in cross-section in Fig. 8B with the seal forming structure 3100 and air circuit 4170 in place. The first end 3612A of the body 3612 of the decoupling structure is configured as a ring- or cuff-like structure that engages in a snap-fit arrangement with a complementary structure provided to the frame 3900. The snap-fit arrangement is configured to allow the decoupling structure 3610 to axially swivel / rotate about the first end 3612A relative to the plenum chamber 3200. Other arrangements that may facilitate axial swivelling or rotation of the decoupling structure 3610 relative to the patient interface may be envisaged.

[0266] As shown here, the first end 3612A is a separate structure of a suitable rigid and durable plastics material, such as polycarbonate, to the main body 3612 and is bonded or otherwise secured to same via ultrasonic welding techniques or other fastening arrangements. However, in other examples, the first end 3612A may be integrally formed with the main body 3612 as a one-piece moulding or component.

[0267] Provided internally to the main body 3612 of the decoupling structure 3610 is a flange 3616, which may be integrally formed to the main body 3612, and projecting inwards from the inner circumference of same. The inner circumference of the flange 3616 forms a central bore through which pressurised air flows from the air circuit 4170 into the plenum chamber 3200 (and to which the air circuit 4170 connects). As shown in Fig. 8B, due to the inferior side of the main body 3612 being reduced in length relative to the superior side, the flange 3616 is part of an L-shaped structure, e.g. a structure with an axially extending portion as well as a radially extending portion. However, the opposing side of the flange 3616 (the upper side in the orientation of Fig. 8B) extends substantially perpendicularly from the internal surface of the main body 3612. In other examples, the decoupling structure may be greater in length from its opposing first and second ends 3612A, 3612B, such that there is sufficient clearance for the flange 3616 to be configured such that it extends perpendicularly about the entire circumference of the inner surface of the main body 3612.

[0268] The flange 3616 is to be understood to have a superior or downstream side, facing the plenum chamber 3200 in use while an inferior or upstream side faces the air circuit 4170. Reference to upstream / downstream is in relation to the flow ofA2578192 12.0 45Ref: P2755WO1 / 506986PCT1the pressurised air passing through the air circuit 4170 from the RPT device (not shown). The decoupling structure 3610 in this example comprises apertures 3618 passing through from one side of the skirt 3616 to the other side of the skirt, e.g. at regular intervals. These allow flow of washout gases from the plenum chamber 3200 through to the passage 3614. This provides a vent 3400.

[0269] The connection port 3600 is in the form of a cuff or connector that engages with the bore defined by the inner circumference of the flange 3616. The connection may be a press fit connection or may be a snap-fit arrangement, for example. The connection port 3600 may include a lip 3602 circumscribing its external surface while its internal surface(s) is configured to receive the downstream end of the air circuit 4170.

[0270] In some examples, such as the example shown in Fig. 8B, between this lip 3602 and the inferior side of the flange 3616 of the main body 3612 is retained a diffuser element 3448. The diffuser element 3448, which as previously discussed above is of a suitable biocompatible material such as an open-celled foam, fabric, wool, polymers or a felt such as a silicone or polyurethane foam felt, comprises an annular or ring-shaped profile, substantially corresponding to the profile of the flange 3616 of the main body 3612. A vent flow of gases, including gases exhaled by the patient enter the diffuser element 3448 (or flow into it) via the apertures 3618, and its flow rate and / or energy is reduced, thereby reducing noise and becoming diffused. A portion of the diffuser element may at least partially fill the gap 3614 formed by the exterior surface of the connection port and the interior surface of the upstream end 3612B of the main body 3612. By this flow path, from the plenum chamber 3200 to the apertures 3618 and then through the diffuser element 3448 to the gap 3614, the washout gases are sent to the ambient environment.

[0271] The connection port 3600, being held in a snap-fit arrangement with the skirt 3616 provided to the interior of the body 3612 of the decoupling structure 3610, may be able to be removed by the patient or other persons to facilitate access to and removal of the diffuser for cleaning and / or replacement. As such, the patient interface may be quickly adapted for use by different patients by replacing the diffuser and seal-forming structure, the portions of the patient interface that create the most significant hygiene issues.

[0272] The main body 3612 of the decoupling structure 3610 is shown in Fig. 8C, with the interior clearly shown. As can be seen, the array of apertures 3618 isA2578192 12.0 46Ref: P2755WO1 / 506986PCT1arranged about the flange 3616 provided to the interior of the main body 3612. In this example, the apertures 3618 are discrete holes, but they may take other forms; for example, the apertures may be a series of arcuate slots or even a single circumferentially arranged slot, with a bridge portion retaining the inner circumference of the flange 3616. The dimensions and number of apertures provided may depend on the volume of the washout gas to be vented.

[0273] As discussed in respect of Fig. 8B, in this example the first end (3612A -not shown) is a separate structure to the main body 3612 (in other examples it may be integrally formed with the main body). As will be noted, this engages with and is bonded to the lip 3620 that circumscribes the downstream end of the main body 3612. In this view, the configuration of the flange 3616 on its inferior side is readily visible; due to the reduced space in this area of the main body 3612, a neck portion 3617 extends axially from the inner surfaces of the main body 3612. The flange 3616 then extends perpendicularly from the neck portion 3617 (e.g. the end of the neck portion 3617, forming the L-shaped structure referenced above). Also visible in this view is the central bore 3622, defined by the inner circumference of the flange 3616 and which receives the connection port (not shown) in use.

[0274] As previously noted, the decoupling structure 3610 of the present technology is not limited to use with nasal masks, such as is shown in Figs. 8A and 8B. For example, the decoupling structure may be readily used with a suitably configured patient interface (such as the oro-nasal mask 3000 of Fig. 1C). The decoupling structure may also be swapped between different mask-types (for example from a nasal mask to an oro-nasal mask or vice versa) so long as the respective cooperating surfaces are suitably configured. Such an arrangement may enhance modularity of patient interfaces as herein described.4.3.7 Frame and cushion module

[0275] Figs. 9A-9D show views of another patient interface 3000 according to an example of the present technology. In this example, the patient interface 3000 comprises a plenum chamber 3200 pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure. The plenum chamber 3200 may include at least one plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient. The patient interface 3000 may also comprise a seal -forming structure 3100 constructed and arranged to form a seal with aA2578192 12.0 47Ref: P2755WO1 / 506986PCT1region of the patient’s face surrounding an entrance to the patient’s airways, the sealforming structure 3100 having a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares. The sealforming structure 3100 may be constructed and arranged to maintain said therapeutic pressure in the plenum chamber 3200 throughout the patient’s respiratory cycle in use. The patient interface 3000 comprises a positioning and stabilising structure 3300 to provide a force to hold the seal-forming structure 3100 in a therapeutically effective position on the patient’s head. In this example, the positioning and stabilising structure 3300 comprises a frame 3900 and headgear 3302 connected to the frame 3900. Figs. 14A and 14B show another patient interface 3000 similar to the patient interface 3000 shown in Figs. 9A-9D. The headgear 3302 shown in Figs. 14A and 14B is suitable for use in the patient interface 3000 shown in Figs. 9A-9D, e.g. by connecting to the frame 3900 in the same way as shown in Figs. 14A and 14B.

[0276] In the example shown in Figs. 9A-9D, the patient interface 3000 comprises a cushion module 3150 forming the seal-forming structure 3100 and at least partially forming the plenum chamber 3200. The patient interface 3000 shown in Figs. 9A-9D has a similar overall configuration as that of Figs. 8A-8C in relation to the provision of a cushion module 3150, frame 3900 and decoupling structure 3610 and how these components connect together. Only certain differences will be discussed in detail below.

[0277] The cushion module 3100 is shown in isolation in Figs. 10A-10F and is configured to connect to the frame 3900 in use. In this example, the cushion module 3150 comprises a cushion module connection portion 3151 defining an anterior opening of the cushion module 3150. The frame 3900 is shown in Figs. 12A-12C in isolation and comprises a frame connection portion 3951.4.3.7.1 Complementary features

[0278] In the example shown in Figs. 9A-12C, the cushion module connection portion 3151 comprises a perimeter configured to sealingly engage a perimeter of the frame connection portion 3951 to fluidly connect the cushion module 3150 to the frame 3900 in use. The perimeter of the cushion module connection portion 3151 and the perimeter of the frame connection portion 3951 may be correspondingly shaped perimeters.A2578192 12.0 48Ref: P2755WO1 / 506986PCT1

[0279] In this example of the present technology, the cushion module 3150 and the frame 3900 comprise at least one pair of complementary features in addition to the correspondingly shaped perimeters. The at least one pair of complementary features may advantageously prevent incorrect orientation of the cushion module 3150 with respect to the frame 3900 during assembly of the cushion module 3150 to the frame 3900. This may help prevent patients correctly assembly the cushion module 3150 to the frame 3900 in the correct orientation (e.g. preventing inadvertent upside down assembly).

[0280] In the example shown in Figs. 9A-12C, the correspondingly shaped perimeters of the cushion module 3150 and frame 3900 are circular perimeters. The at least one pair of complementary features in addition to the correspondingly shaped perimeters may be particularly advantageous when the correspondingly shaped perimeters are circular, because a circular interface between the cushion module 3150 and the frame 3900 may not alone prevent assembly at an incorrect orientation. In other examples the correspondingly shaped perimeters may not be circular and may be, by way of example only, triangular or trapezoidal with rounded vertices and / or sides, or rectangular with rounded corners and / or ends. Even when the correspondingly shaped perimeters are not circular, the provision of at least one pair of complementary features in addition to the correspondingly shaped perimeter may further assist the patient to assemble the cushion module 3150 to the frame 3900 for example by at least making it easy for the patient to quickly identify the correct orientation of the cushion module 3150 with respect to the frame 3900.

[0281] As shown especially in Figs. 9D, 10A, 10E and 10F, the cushion module connection portion 3151 in this example comprises an inwardly facing lip. As shown especially in Figs. 9D and 12B, the frame connection portion 3951 comprises an outwardly facing channel structured to receive the inwardly facing lip. In other examples, the cushion module connection portion 3151 may comprise an outwardly facing lip and the frame connection portion 3951 may comprise an inwardly facing channel structured to receive the outwardly facing lip. In further examples, the cushion module connection portion 3151 may comprise an inwardly facing channel and the frame connection portion 3951 may comprise an outwardly facing lip configured to be received in the channel, or the cushion module connection portionA2578192 12.0 49Ref: P2755WO1 / 506986PCT13151 may comprise an outwardly facing channel and the frame connection portion 3951 may comprise an inwardly facing lip configured to be received in the channel.

[0282] With reference to Figs. 10E and 10F, in this example the seal-forming structure 3100 is formed from a first material 3156 and the inwardly facing lip is formed from a second material 3157 having a greater hardness than the first material 3156. Both the first material 3156 and the second material 3157 may be elastomeric materials, such as silicone or TPE, for example. In this example, the first material 3156 is a first silicone material and the second material 3157 is a second silicone material, the second silicone material having a greater durometer hardness than the first silicone material. The greater durometer hardness may advantageously provide, in actuality or at least in patient perception, for a robust fit, easy assembly and / or good seal between the cushion module 3150 and the frame 3900.

[0283] In other examples, one of the first material 3156 and second material 3157 may be silicone and the other may be TPE. In other examples the first material 3156 is elastomeric and the second material 3157 may be a substantially rigid material, such as a thermoplastic material, e.g. polycarbonate, polypropylene, polyethylene, nylon or the like. The first material 3156 and second material 3157 may also differ in other properties, such as colour or transparency. In one example the first material 3156 and second material 3157 may both be silicone materials but the second material 3156 may be tinted to colour code the seal-forming structure 3100 based on its size.

[0284] Turning to the complementary features references above, in the patient interface 3000 shown in Figs. 9A-12C, the at least one pair of complementary features comprises a protrusion and a recess, one of the protrusion and the recess being provided to the frame 3900 and the other of the protrusion and the recess being provided to the cushion module 3150.

[0285] One pair of complementary features provided to the patient interface 3000 shown in Figs. 9A-12C is a superior pair of complementary features comprising a superior protrusion 3953 (see Figs. 9D and 12A-12C) of the frame 3900 and a correspondingly shaped superior portion of the cushion module 3150 configured to receive the superior protrusion 3953. In this particular example the correspondingly shaped superior portion of the cushion module 3150 is a recess 3153 (see Figs. 9D,A2578192 12.0 50Ref: P2755WO1 / 506986PCT110A and 1OF). As illustrated in Fig. 1OA for example, the recess 3153 in this example is recessed with respect to an exterior surface of the cushion module 3150.

[0286] Another pair of complementary features provided to the patient interface 3000 shown in Figs. 9A-12C is an inferior pair of complementary features comprising an inferior protrusion 3954 (see Figs. 9D and 12A-12C) of the frame 3900 and a correspondingly shaped inferior portion of the cushion module 3150 configured to receive the inferior protrusion 3954. The correspondingly shaped inferior portion is in this example defined between a pair of inferior protrusions 3154 of the cushion module 3150 (see Figs. 10B, 10E and 10F). When the patient interface 3000 is assembled, the inferior protrusions 3154 of the cushion module 3150 are positioned on respective lateral sides of the inferior protrusion 3154 of the frame 3900. The correspondingly shaped inferior portion may comprise a space defined by one or more features of the cushion module 3150 into which the inferior protrusion 3154 of the frame 3900 is able to fit. In the example shown in Figs. 9A-12C, the inferior protrusions 3154 are provided internally to the cushion module 3150.

[0287] In other examples only one pair of the superior pair of complementary features and the inferior pair of complementary features may be provided to a patient interface 3000.4.3.7.1 Selected features of the seal-forming structure

[0288] It is to be understood that the features of the decoupling structure 3610 and frame 3900 described herein may be applied to a patient interface 3000 having a seal-forming structure 3100 of any suitable construction. With reference to Figs. 10E, 10F and 11, the seal -forming structure 3100 in this particular example comprises a superior portion 3112 which is thinner than lateral patient-facing portions 3114 of the seal-forming structure 3100. In this example, the superior portion 3112 extends substantially from a patient-facing surface to the cushion module connection portion 3151 configured to connect to the frame 3900. The superior portion 3112 may include, or be adjacent to, a nasal ridge portion 3116 of the seal-forming structure 3100 which is configured to seal to the patient’s nasal ridge in use. Additionally, the superior portion 3112 is wider than the nasal ridge portion 3116. The superior portion 3112 may also be thinner than lateral-facing portions 3113 of the cushion module 3150 and may be aligned horizontally with the lateral-facing portions 3113 of theA2578192 12.0 51Ref: P2755WO1 / 506986PCT1cushion module 3150 (e.g. the superior portion 3112 or at least an anterior portion thereof may be positioned superior to and aligned in the anterior-posterior direction with the lateral-facing portions 3113). The lateral -facing portions 3113 of the cushion module 3150 may also be thicker than the lateral patient-facing portions the sealforming structure 3100. The relationship between the thicknesses of these different portions may advantageously provide for a cushion module 3150 with a well-supported seal-forming structure 3100 due to the thicker lateral-facing portions 3113 of the cushion module 3150, while providing for good compliance, seal and comfort due to the thinner lateral patient-facing portions 3114 and nasal ridge portion 3116 of the seal -forming structure 3100. Furthermore, the generous transverse width, anterior-posterior depth, and / or low thickness, of the superior portion 3112 may advantageously accommodate for and avoid excess pressure on the nasal ridge in patients with high or prominent nasal ridges.

[0289] The seal-forming structure 3100 may also comprise flaps 3110 configured to seal against the sides of the patient’s nose in use, the flaps 3110 may extend medially from the lateral patient-facing portions 3114 of the seal-forming structure 3100. The flaps 3110 may advantageously improve the seal at the sides of the patient’s nose and / or resist blowout. The flaps 3110 may curve medial and anteriorly to be shaped generally complementary to the surfaces of the nose that they lie against in use. Each flap 3110 may comprise a medial edge which is not connected back to another portion of the seal-forming structure 3100 or cushion module 3150. For example, each flap 3110 may comprise a free medial edge. Each flap 3110 may be cantilevered and / or curl medially from the lateral patient-facing portions 3114.

[0290] Fig. 15 shows a posterior view of the seal-forming structure 3100 with additional regions identified and delineated by broken lines. The flaps 3110 and nasal ridge portion 3116 are shown and labelled. In this example, as shown, each lateral patient-facing portion 3114 comprises or is formed by multiple portions, as will be discussed. The seal-forming structure 3100 comprises a hole 3101 to provide the flow of air to an entrance to the patient’s nares in use. The patient’s nose may be at least partially received in the hole 3101 in use.

[0291] In this example, the seal-forming structure 3100 comprises the nasal ridge portion 3116 positioned to seal to the patient’s nasal ridge in use, an inferior portionA2578192 12.0 52Ref: P2755WO1 / 506986PCT13111, the pair of lateral patient-facing portions 3114 each connecting between the nasal ridge portion 3116 and the inferior portion 3111 on a respective lateral side of the cushion module 3150, and a pair of flaps 3110 each extending medially from a respective one of the lateral patient-facing portions 3114 and each positioned to engage a respective lateral side of the patient’s nose. In this example the seal -forming structure 3100 has a greater thickness in each of the pair of flaps 3110 than in the nasal ridge portion 3116 and the inferior portion 3111. In other examples the sealforming structure 3100 may have a greater thickness in each of the pair of flaps 3110 than in the nasal ridge portion 3116 but not the inferior portion 3111. In further examples the seal-forming structure 3100 may have a greater thickness in each of the pair of flaps 3110 than in the inferior portion 3111 but not the nasal ridge portion 3116. Advantageously, the nasal ride portion 3116, flaps 3110 and inferior portion 3111 are all thin for good compliance and comfort, while other portions of the sealforming structure 3100 further from the edge of the hole 3101 are stiffer to provide good support in use. Additionally, the flaps 3110 in this example are advantageously increased in thickness in comparison to the nasal ridge portion 3116 and inferior portion 3111 to provide improved seal performance at the sides of the patient’s nose. That is, the flaps 3110 may advantageously be thin to provide for good comfort, but patients may tolerate the flaps 3110 being thicker than the nasal ridge portion 3116 and inferior portion 3111 to provide for better seal performance than if the flaps 3110 were the same thickness as the nasal ridge portion 3116 and the inferior portion 3111.

[0292] In the example shown in Fig. 15, the inferior portion 3111 is positioned to seal to the patient’s lip superior. In this example the cushion module 3150 is for a nasal mask. In other examples the inferior portion 3111 is positioned to seal to the patient’s face against or inferior to the patient’s lip inferior. In such an example the cushion module 3150 would form part of a full-face mask.

[0293] The seal-forming structure 3100 may have a thickness of between 0.2-0.3mm in the nasal ridge portion, for example 0.25mm. The seal-forming structure 3100 may have a thickness of between 0.2-0.3mm in the inferior portion, for example 0.25mm. Furthermore, the seal -forming structure 3100 may have a thickness between 0.3-0.5mm in each of the flaps, such as between 0.3-0.4mm, such as 0.33mm.A2578192 12.0 53Ref: P2755WO1 / 506986PCT1

[0294] As is also shown in Fig. 15, the seal -forming structure 3100 in this example comprises a pair of inferolateral portions 3117 each in an inferior and lateral position on a respective lateral side of the seal-forming structure 3100. Each inferolateral portion 3117 may be positioned laterally of the inferior portion. The sealforming structure may have a greater thickness in the inferolateral portions 3117 than in the inferior portion 3111. In some examples the thickness of the inferolateral portions may be in the range of 0.5mm-2mm, such as 0.7-1.7mm or 0.9-1.5mm. In some examples, each of the inferolateral portions 3117 increases in thickness away from the hole 3101 of the seal-forming structure 3100. The inferolateral portions 3117 may seal to the patient’s face proximate the nasolabial sulci.

[0295] The seal-forming structure 3100 in this example also comprises a pair of superolateral portions 3115 each on a respective lateral side of the seal -forming structure 3100. Each superolateral portion 3115 may be positioned superiorly of the inferolateral portions 3117 and inferiorly of the nasal ridge portion 3116. At least a portion of each superolateral portion is thicker than the nasal ridge portion 3116, in this example. Each of the superolateral portions is in this example adjacent a respective one of the pair of flaps 3110. In some examples, the thickness of the superolateral portions 3115 may be within the range of 0.3-1.5mm, such as 0.33-1.3mm. In some examples, each of the superolateral portions 3115 increases in thickness away from the hole 3101 of the seal-forming structure 3100.

[0296] Also in the example shown in Fig. 15, the seal-forming structure comprises a pair of lateral portions 3118 each on a respective lateral side of the sealforming structure 3100. Each lateral portion 3118 is, in this example, positioned at least partially inferior to a respective one of the superolateral portions 3115 and at least partially superior to a respective one of the inferolateral portions 3117. In this example the inferolateral portions 3117 each surround a respective one of the lateral portions 3118 on inferior, medial and superior sides of the lateral portions 3118. Each lateral portion 3118 may be thicker than either or both of the inferolateral portions 3117 and / or the superolateral portions 3115. In this example the lateral portions 3118 are thicker than both the inferolateral portions 3117 and the superolateral portions 3115. The lateral portions 3118 may have a thickness within the range of 1.2-2.5mm, such as within the range of 1.3-2mm or within the range of 1.33-1.8mm. The lateralA2578192 12.0 54Ref: P2755WO1 / 506986PCT1portions 3118 may each increase in thickness in a direction away from the hole 3101 of the seal-forming structure 3100.

[0297] Additionally, the seal -forming structure 3100 in this example comprises a pair of superior stiffened portions 3119 each positioned on a respective lateral side of the seal -forming structure 3100 between the nasal ridge portion 3116 and a respective one of the superolateral portions 3115. The seal -forming structure 3100 having a greater thickness in each of the superior stiffened portions 3119 than in the nasal ridge portion 3116. In this example, a medial portion of each of the superior stiffened portions 3119 is greater in thickness than an adjacent portion of the respective superolateral portion 3115. Also in this example, each of the superior stiffened portions 3119 increases in thickness away from the hole 3101 of the seal-forming structure 3100. The superior stiffened portions 3119 may have a thickness within the range of 0.6-1.5mm, such as 0.7-1.4mm or 0.8-1.3mm.4.3.7.3 Frame and arms

[0298] With reference to Figs. 12A-12C, in this example the frame 3900 comprises a central portion 3901 configured to connect directly or indirectly to a cushion module 3150 of the patient interface 3000 (e.g. the cushion module shown in isolation in Figs. 10A-10F). Frames 3900 according to the present technology may more generally be configured to connect directly or indirectly to a cushion module 3150 at least partially forming a plenum chamber 3200 of the patient interface 3000 and comprising a seal-forming structure 3100 constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways.

[0299] The frame 3900 further comprises a pair of arms 3902 extending from the central portion 3901 on respective lateral sides thereof. Each arm 3902 may comprise a medial portion 3905, a superior portion 3903 and an inferior portion 3904 (see Fig.12D) The medial portion 3905 may be connected at a medial end thereof to the central portion 3901. The superior portion 3903 may extend at least partially superiorly from a lateral end of the medial portion 3905 and may comprise a superior headgear connector at a superior end thereof. The superior headgear connector 3910 may be any suitable type of connector for connecting to a strap portion of a headgear 3302. In the example shown in Figs. 12A-12C the superior headgear connector 3910 is a slot through which a headgear strap portion can pass through and be secured back to itself,A2578192 12.0 55Ref: P2755WO1 / 506986PCT1as shown in Figs. 14A-14B. The inferior portion 3904 of each arm 3902 may extend at least partially inferiorly from the lateral end of the medial portion 3905 and may comprise an inferior headgear connector 3920 at an inferior end thereof. The inferior headgear connector 3920 may be any suitable type of connector for connecting to a strap portion of a headgear 3302. In the example shown in Figs. 12A-12C, the inferior headgear connector 3920 is a magnet configured to be magnetically engaged by a corresponding connector (e.g. a magnet or ferromagnetic material) on a headgear strap portion.

[0300] As shown in Figs. 14A and 14B, the headgear 3302 of the positioning and stabilising structure 3300 may comprise a pair of superior strap portions 3311 configured to connect to the superior headgear connectors 3910 and a pair of inferior strap portions 3312 configured to connect to the inferior headgear connectors 3920. The headgear 3302 may further comprise a crown strap portion 3314 configured to engage superior and posterior surfaces of the patient’s head, and may further comprise a neck pad 3313 at a junction between the inferior strap portions 3312 and the crown strap portion 3314.

[0301] The superior headgear connectors 3910 in this example comprises slots. Each of the superior strap portions 3311 may connect to the superior headgear connectors 3910 by passing through the slots and being secured back to itself, for example with a hook-and-loop connection. The inferior headgear connectors 3920 may each comprise a magnet configured to be engaged a corresponding clip on a respective one of the inferior strap portions 3312, the clip having a magnet or ferromagnetic material to engage the magnet of the inferior headgear connector 3920. In other examples the clip on each inferior strap portion 3312 may comprise a magnet and the inferior headgear connector 3920 may comprise a ferromagnetic material to attract the magnet.

[0302] As shown in Figs. 12A-12C and 13A, each arm 3902 comprises a pad 3930 positioned to engage the user’s head in use. The pad 3930 may form at least part of the superior portion 3903, the inferior portion 3904 and a junction 3906 between the superior portion 3903, the inferior portion 3904 and the medial portion 3905 of the respective arm 3902.A2578192 12.0 56Ref: P2755WO1 / 506986PCT1

[0303] Each arm 3902 may also comprise a rigidising material 3940 attached to the pad 390 in at least the superior portion 3903, the inferior portion 3904 and the junction 3906. Figs. 13B-13C show three examples of rigidising material 3940 in isolation. As shown, the rigidising material 3940 may form or support the superior headgear connector 3910 and inferior headgear connector 3920. In the examples shown in Figs. 12A-13C, the rigidising material 3940 may comprise a junction rigidising portion 3946 located at the junction 3906, a superior end rigidising portion 3943 located at or proximate the superior end of the superior portion 3903, and an inferior end rigidising portion 3944 located at or proximate the inferior end of the inferior portion 3904.

[0304] The examples shown in Figs. 13B-13D include different thicknesses in different portions of the rigidising material 3940 (and therefore in different portions of the arm 3902). In some examples, the thickness of the rigidising material 3940 may be greater in the junction rigidising portion 3946 than in the superior end rigidising portion 3943 and / or the inferior end rigidising portion 3944. For example, Figs. 13C and 13D show examples in which the thickness of the rigidising material 3940 is greater in the junction rigidising portion 3946 than in both the superior end rigidising portion 3943 and the inferior end rigidising portion 3944. Fig. 13B shows another example in which the thickness of the rigidising material 3940 is substantially the same in each of the junction rigidising portion 3946, superior end rigidising portion 3943 and inferior end rigidising portion 3944.

[0305] In the examples shown in Figs. 13C and 13D, the junction rigidising portion 3946 extends from the junction 3906 along at least half of the length of the superior portion 3903 of the arm 3902. In the example shown in Fig. 13D, the junction rigidising portion 3946 extends from the junction3906 along more than half of the length of the superior portion 3903. Similarly, the junction rigidising portion 3946 may extend from the junction 3906 along at least half of the length of the inferior portion 3904. In each of the examples shown in Figs. 13C and 13D, the junction rigidising portion 3946 extends from the junction 3906 along more than half of the length of the inferior portion 3904.

[0306] By way of example, the rigidising material 3940 may have a thickness within the range of 1.5-2mm in the junction rigidising portion 3946. The rigidisingA2578192 12.0 57Ref: P2755WO1 / 506986PCT1material 3940 may have a thickness within the range of 1.3-1.7mm in the superior end rigidising portion 3943, such as 1.5mm and may have a thickness within the range of 1.3-1.7mm in the inferior end rigidising portion, such as 1.5mm.

[0307] As shown in each of Figs. 13B-13D, the rigidising material 3940 in these examples comprises a posterior edge rigidising portion 3947 provided proximate a posterior edge of the pad 3930. The rigidising material 3940 may have a lesser thickness in the posterior edge rigidising portion 3947 than in the junction rigidising portion 3946. Additionally, or alternatively, the rigidising material 3940 a lesser thickness in the posterior edge rigidising portion 3947 than in the superior end rigidising portion 3943 and / or the inferior end rigidising portion 3944. In some examples, the rigidising material 3940 has a thickness within the range of 0.4-lmm in the posterior edge rigidising portion 3947, such as 0.5mm or 0.7mm.

[0308] The rigidising material 3940 may also be attached to the pad 3930 in the medial portion 3905 and the rigidising material 3940 may comprise a medial rigidising portion 3945 in the medial portion 3905 located medially of the junction rigidising portion 3946. In the examples shown in Figs. 13C and 13D, the thickness of the rigidising material 3940 is greater in the junction rigidising portion 3946 than in the medial rigidising portion 3945. In the example shown in Fig. 13B, the rigidising material 3940 has substantially the same thickness in the junction rigidising portion 3946 and the medial rigidising portion 3945. In some examples, the rigidising material 3940 has a thickness within the range of 1.3-1.7mm in the medial rigidising portion 3945, such as 1.5mm.

[0309] Advantageously, the stiffening of the arm 3902 by the rigidising material 3940 proximate the junction 3906 may resist buckling that may occur in the arm 3902 at the junction 3906 or along the posterior edge of the arm 3902. The relative stiffnesses of the rigidising material 3940 within the arm 3902, that is, greater stiffness at the junction 3906 than in the superior portion 3903, inferior portion 3904 and / or medial portion 3905, may advantageously provide for resistance against buckling at the junction while providing for good flexibility in each of the other portions to flex to conform to the shape of the patient’s head in use.A2578192 12.0 58Ref: P2755WO1 / 506986PCT1

[0310] In some examples, the rigidising material 3940 is polypropylene. The absolute values of the thicknesses provided above are based on the rigidising material 3940 being polypropylene. In other examples the rigidising material 3940 may be an elastomeric material such as silicone or TPE (e.g. Hytrel), or may be another thermoplastic material such as polycarbonate, polyethylene, Nylon, ABS or the like.

[0311] In each arm, the rigidising material 3940 extends medially away from the pad 3930 to form a medial end of the arm 3902. The rigidising material 3940 may be connected to the central portion 3901 of the frame 3900. In the example shown in Figs. 12A-12C, the rigidising material 3940 is integrally formed with the central portion 3901 of the frame 3900. The rigidising material 3940 in this example is overmoulded to the pad 3930. In other examples the rigidising material 3940 may be adhered or welded to the pad 3930.

[0312] Each respective pad 3930 may cover all, or only some, of each of the medial portion 3905, superior portion 3903 and inferior portion 3904, of each respective arm 3902. In the example shown in Figs. 12A-12C, each pad 3930 is provided to a majority of the medial portion 3905 of its respective arm 3902. In the example shown in Figs. 14A-14B, the majority of the medial portion 3905 of each arm 3900 is not covered by the pad 3930. The portion of the medial portion 3905 proximate the central portion 3901 of the frame 3900 is spaced from the patient’s face in use, meaning it may not be necessary to cover the full length of the medial portion 3905 with the pad 3930. Therefore, some or all of the medial portion 3905, for example a non-face-contacting portion of the medial portion 3905, may be left uncovered by the pad 3930. In the example shown in Figs. 14A and 14B, the rigidisng material 3940 extends from the central portion 3901 of the frame 3900 and is attached only to a non-face-contacting side of the pad 3930. In the example shown in Figs. 12A-12C, the rigidising material 3940 extends from the central portion 3901, passes through the pad 3930 from a face-contacting side to a non-face-contacting side, and is attached to the non-face-contacting side.4.3.8 Connection port

[0313] Connection port 3600 allows for connection to the air circuit 4170. As described in respect of Figs. 8 A and 8B, the decoupling structure may be, or form part of, the connection port 3600.A2578192 12.0 59Ref: P2755WO1 / 506986PCT14.3.9 Forehead support

[0314] In one form, the patient interface 3000 includes a forehead support 3700.4.3.10 Anti-asphyxia valve

[0315] In one form, the patient interface 3000 includes an anti-asphyxia valve.4.3.11 Ports

[0316] In one form of the present technology, a patient interface 3000 includes one or more ports that allow access to the volume within the plenum chamber 3200. In one form this allows a clinician to supply supplementary oxygen. In one form, this allows for the direct measurement of a property of gases within the plenum chamber 3200, such as the pressure.4.3.12 Modularity

[0317] As described above, the cushion, headgear, and sleeves may come in different styles, which may correspond to different uses (e.g., mouth breathing, nasal breathing, etc.). A patient or clinician may select certain combinations of cushions, headgear, and sleeves in order to optimize the effectiveness of the therapy and / or the individual patient’s comfort. An example of this sort of modular design is described in PCT / SG2022 / 050777 filed 28 October 2022, incorporated herein by reference in its entirety.

[0318] In some forms, the different styles of cushions, headgear, and sleeves may be used interchangeably with one another in order to form different combinations of patient interfaces. This may be beneficial from a manufacturing prospective because wider variety of patient interfaces may be created using fewer parts. Additionally or alternatively, the various combinations may allow a patient to change styles of patient interface without changing the every component.

[0319] Air may be delivered to the patient in one of two main ways. In one example, the patient may receive the flow of pressurized air through headgear tubes 3350 (see e.g., Fig. 6). This may be referred to as a “tube up” configuration and may position a connection port at the top of the patient’s head. In other example, the patient may receive the flow of pressurized air through a conduit connected to the plenum chamber 3200, for example through the connection port 3600 (see e.g., Fig.3 A). This may be referred to a “tube down” configuration where the airflow conduit is positioned in front of the patient’s face. Different patients may be more comfortable with one style of air delivery over the other (e.g., because of the patient’s sleep style).A2578192 12.0 60Ref: P2755WO1 / 506986PCT1Therefore, it may be beneficial to allow a single style of patient interface to be used in either the “tube up” or “tube down” configuration.

[0320] The patient interface may be part of a modular assembly with a variety of interchangeable components that may be swapped out by a patient and / or clinician for one or more components for a different style. The following description describes the various combinations that may be created by assembling the different components together.4.3.12.1 Sleeve

[0321] In some forms, to allow for modularity, a sleeve may be used with the tubes 3350 and / or the rigidisier arms 3340. The sleeve may at least partially surround the tubes 3350 and / or the rigidiser arms 3340. As shown in Figs. 7G to 71, different shapes of sleeves may be used, which may correspond to different types of positioning and stabilising structures 3300. In some forms, the configuration of the sleeve may be customized to fit a particular user’s face. For instance, the sleeves may be configured in a relatively more posterior region of the patient’s head.

[0322] In some forms, the sleeve may be constructed from a comfortable material. For example, the sleeve may be constructed from a textile material, a foam material, or a combination of the two. The comfortable material may contact the patient in use, and may feel soft against the patient’s skin in order to improve patient compliance.

[0323] The material may also be flexible in order to assist in donning or doffing the sleeve from the tube 3350 or the rigidiser arms 3340. For example, the material may allow the sleeve to bend in order to conform to the shape of the tubes or conduit headgear 3350 or the rigidiser arms 3340, which may change depending on the shape of an individual patient’s head.

[0324] In some forms, the sleeve may also be at least partially elastic (e.g., the material may allow the sleeve to stretch). The elastic material may help the sleeve stretch in order to fit around the tubes 3350 or the rigidiser arms 3340. The elastic material may then return to an initial position that is snug against the tubes 3350 or the rigidiser arms 3340 in order to limit the sleeve from sliding while in use.

[0325] As described in more detail below, some forms of the sleeves may be specific to a rigidising element (e.g., tubes 3350 and / or rigidiser arms 3340).However, the sleeves may assist the rigidising elements in connecting interchangeablyA2578192 12.0 61Ref: P2755WO1 / 506986PCT1with the version or styles of cushions (e.g., the mouth and nose cushion 3050-1, the nose-only cushion 3050-2, etc.).4.3.12.1.1 Conduit Sleeve

[0326] As shown in Fig. 7G, one example of a sleeve is a conduit sleeve 3351, which may be usable with the tubes 3350 described above.

[0327] As shown in Fig. 7G, the conduit sleeve 3351 may include a curved shape that may be similar to the shape of the tubes 3350 shown in Fig. 7C. The flexible material used to construct the conduit sleeve 3351 may allow the conduit sleeve 3351 to further curve in order to correspond to the shape of the tubes 3350 (e.g., when worn by the patient).

[0328] In some forms, the conduit sleeve 3351 may include a first or superior opening 3352. The superior opening 3352 may be disposed at one end of the conduit sleeve 3351. The superior opening 3352 may be an opening to a passage that extends along at least a portion of the conduit sleeve 3351.

[0329] As shown in Fig. 7G, some forms of the conduit sleeve 3351 may also include an inferior extension 3354. The inferior extension 3354 may be positioned on an opposite end of the conduit sleeve 3351 from the superior opening 3352. The conduit sleeve 3351 may be customized to fit a particular user’s face. For instance, the inferior extension 3354 of the conduit sleeve 3351 may be configured in a relatively more posterior region or anterior region of the patient’s head.

[0330] Some forms of the inferior extension 3354 may include a rigid or semirigid piece (e.g., within the sleeve 3351). The rigid or semi-rigid piece may be constructed from a plastic material, or a similar material. Alternatively, the inferior extension 3354 may be stiffened using a manufacturing process (e.g., stitching rigidised thread, flat knitting, using thicker material).

[0331] As shown in Fig. 7G, some forms of the inferior extension 3354 may include a connection member 3356. In the illustrated example, the connection member 3356 may be a magnet, although in other examples, the connection member 3356 may be a different type of connector (e.g., a mechanical fastener, an adhesive, hook and loop material, etc.). The connection member 3356 may also be positioned at an end of the inferior extension 3354, although the connection member 3356 could alternatively be positioned anywhere along the inferior extension 3354.

[0332] In some forms, the connection member 3356 (e.g., a magnet) may be removably connected to the magnets 3370-1 of the headgear 3302-1. For example,A2578192 12.0 62Ref: P2755WO1 / 506986PCT1when the conduit sleeves 3351 are connected to the tubes 3350 (see e.g., Fig. 7J), the magnets 3370-1 connected to the inferior straps 3304-1 may be removably connected to the connection member 3356 in order to provide the tensile force.4.3.12.1.2 Four-point arm sleeve

[0333] As shown in Fig. 7H, another example of a sleeve is a four-point arm sleeve 3380, which may be usable with the rigidiser arms 3340 described above.

[0334] As shown in Fig. 7H, the four-point arm sleeve 3380 may include a curved shape that may be similar to the shape of the rigidiser arm 3340 shown in Fig.7D. The flexible material used to construct the four-point arm sleeve 3380 may allow the four-point arm sleeve 3380 to further curve in order to correspond to the shape of the rigidiser arm 3340 (e.g., when worn by the patient and / or went bent by the patient).

[0335] As shown in Fig. 7H, some forms of the four-point arm sleeve 3380 may include an inferior extension 3384. The inferior extension 3384 may be positioned at an end of the four-point arm sleeve 3380.

[0336] In the illustrated example, the shape and / or structure of the inferior extension 3384 is substantially the same as the shape of the inferior extension 3354. For example, the inferior extension 3384 may be more rigid as compared to the rest of the four-point arm sleeve 3380 (e.g., as a result of rigidising thread or rigid material).

[0337] As shown in Fig. 7H, some forms of the inferior extension 3384 may include a connection member 3386. In the illustrated example, the connection member 3386 may be a magnet, although in other examples, the connection member 3386 may be a different type of connector (e.g., a mechanical fastener, an adhesive, hook and loop material, etc.). The connection member 3386 may also be positioned at an end of the inferior extension 3384, although the connection member 3386 could alternatively be positioned anywhere along the inferior extension 3384.

[0338] In some forms, the connection member 3386 (e.g., a magnet) may be removably connected to the magnets 3370-1 of the headgear 3302-1. For example, when the four-point arm sleeves 3380 are connected to the rigidiser arm 3340 (see e.g., Fig. 7K), the magnets 3370-1 connected to the inferior straps 3304-1 may be removably connected to the connection member 3386 in order to provide the tensile force.

[0339] As shown in Fig. 7H, the four-point arm sleeve 3380 may include a pair of tabs 3394, which may be similar to the tab 3320 on the tubes 3350. When the four-A2578192 12.0 63Ref: P2755WO1 / 506986PCT1point arm sleeve 3380 is worn by the patient, the tabs 3394 may be positioned in substantially the same place on the patient’s head as where the tabs 3320 are positioned when the patient wears the tubes 3350.4.3.12.1.3 Two-point arm sleeve

[0340] As shown in Fig. 71, yet another example of a sleeve is a two-point arm sleeve 3380-1, which may be usable with the rigidiser arms 3340 described above.

[0341] In some forms, the two-point arm sleeve 3380-1 may be similar to the four-point arm sleeve 3380 described above. Only some similarities and differences may be described below.

[0342] As shown in Fig. 71, the two-point arm sleeve 3380-1 may include an inferior opening 3388-1 that is positioned at an end of the two-point arm sleeve 3380-1. The inferior opening 3388-1 may form an opening to a passageway through the two-point arm sleeve 3380-1. In the illustrated example, the inferior opening 3388-1 may open into a surface of the conduit sleeve 3380-1.

[0343] As shown in Fig. 71, the two-point arm sleeve 3380-1 may include a pair of tabs 3394-1, which may be similar to the tab 3320 on the tubes 3350. When the two-point arm sleeve 3380-1 is worn by the patient, the tabs 3394-1 may be positioned in substantially the same place on the patient’s head as where the tabs 3320 are positioned when the patient wears the tubes 3350.4.3.12.2 Assembled Patient Interfaces

[0344] As illustrated in Figs. 7J to 7M, the various elements described above may be combined into four different patient interfaces. The different patient interfaces may allow patients to use different styles based on their individual comfort. The modularity of the different elements (e.g., the ability to be used in multiple styles of patient interfaces) may simplify manufacturing and / or may allow a patient to more easily switch between styles of patient interfaces.4.3.12.2.1 Nose and Mouth Mask Tube Up Configuration

[0345] As illustrated in Fig. 7J, the patient may wear the cushion 3050-1 in a tube-up configuration with the tubes 3350 and the four-point headgear 3302-1. This assembly may form a tube up nose and mouth patient interface 3000-1.

[0346] In some forms, a conduit sleeve may be used with the tubes 3350 in order to enable a patient to experience the “tube up” air delivery style with the mouth and nose cushion 3050-1. As is described below, the conduit sleeve provides additionalA2578192 12.0 64Ref: P2755WO1 / 506986PCT1connection locations for connecting the four-point headgear 3302-1. However, other forms of connectors aside from or in addition to the conduit sleeve may be used.

[0347] In the illustrated example, the conduit sleeves may be connected to the tubes 3350 of the positioning and stabilising structure 3300. The tubes 3350 (via the conduit connection structure 3500), may be used to connect the tubes 3350 to the cushion 3050-1. The conduit sleeves provide the magnets in order to connect to the magnets 3370-1 (see e.g., Fig. 7E) of the four-point headgear 3302-1. Alternatively, a different connection form may be used.

[0348] As illustrated in Fig. 7J, the four-point headgear 3302-1 may connect in four separate locations in order to provide a tensile force that maintains the cushion 3050-1 in a sealing position on the patient’s head.

[0349] For example, the inferior straps 3304-1 (e.g., via the magnetic members 3306-1) may removably connect to the magnets of the conduit sleeves. In use, each inferior strap 3304-1 may contact the patient’s cheek (e.g., overlaying the masseter muscle). The inferior straps 3304-1 may also extend below the patient’s ears.4.3.12.2.2 Nose and Mouth Mask Tube Down Configuration

[0350] As illustrated in Fig. 7K, the patient may wear the cushion 3050-1 in a tube-down configuration with the rigidiser arms 3340 and the four-point headgear 3302-1. This assembly may form a tube down nose and mouth patient interface 3000-2.

[0351] In some forms, a conduit sleeve may be used with the rigidiser arms 3340 in order to enable a patient to experience the “tube down” air delivery style with the mouth and nose cushion 3050-1. As is described below, the conduit sleeve provides additional connection locations for connecting the four-point headgear 3302-1.However, other forms of connectors aside from or in addition to the conduit sleeve may be used.

[0352] In the illustrated example, the conduit sleeves may be connected to the rigidiser arms 3340 of the positioning and stabilising structure 3300. The rigidiser arms 3340 (via the conduit connection structure 3504), may be used to connect the rigidiser arms 3340 to the cushion 3050-1. The conduit sleeves provide the magnets in order to connect to the magnets 3370-1 (see e.g., Fig. 7E) of the four-point headgear 3302-1. Alternatively, a different connection form may be used.A2578192 12.0 65Ref: P2755WO1 / 506986PCT1

[0353] As illustrated in Fig. 7K, the four-point headgear 3302-1 may connect in four separate locations in order to provide a tensile force that maintains the cushion 3050-1 in a sealing position on the patient’s head.

[0354] For example, the inferior straps 3304-1 (e.g., via the magnetic members 3306-1) may removably connect to the magnets of the conduit sleeves. In use, each inferior strap 3304-1 may contact the patient’s cheek (e.g., overlaying the masseter muscle). The inferior straps 3304-1 may also extend below the patient’s ears.4.3.12.2.3 Nose Mask Tube Up Configuration

[0355] As illustrated in Fig. 7L, the patient may wear the cushion 3050-2 in a tube-up configuration with the tubes 3350 and the two-point headgear 3302-2. This assembly may form a tube up nose only patient interface 3000-3

[0356] A conduit sleeve may be used with the tubes 3350, and may provide additional comfort to the patient. The sleeve may not add additional connection points to connect the positioning and stabilising structure 3300 on the cushion 3050-2. In the illustrated example, the tubes 3350 of the positioning and stabilising structure 3300 may be connected directly to the cushion 3050-2.

[0357] As illustrated in Fig. 7L, the two-point headgear 3302-2 may connect to the tabs 3320 on the tubes 3350 in order to provide a tensile force that maintains the cushion 3050-2 in a sealing position on the patient’s head.4.3.12.2.4 Nose Mask Tube Down Configuration

[0358] As illustrated in Fig. 7M, the patient may wear the cushion 3050-2 in a tube-up configuration with the rigidiser arms 3340 and the two-point headgear 3302-2. This assembly may form a tube down nose only patient interface 3000-4.

[0359] A conduit sleeve may be used with the rigidiser arms 3340, and may provide additional comfort to the patient. The sleeve may not add additional connection points to connect the positioning and stabilising structure 3300 on the cushion 3050-2. In the illustrated example, the rigidiser arms 3340 of the positioning and stabilising structure 3300 may be connected directly to the cushion 3050-2.

[0360] As illustrated in Fig. 7M, the two-point headgear 3302-2 may connect to the tabs 3320 on the sleeve in order to provide a tensile force that maintains the cushion 3050-2 in a sealing position on the patient’s head.4.3.12.2.5 Modularity of Elements

[0361] Fig. 7P illustrates how the different elements can be combined in order to form the four different patient interfaces described above. As illustrated, the differentA2578192 12.0 66Ref: P2755WO1 / 506986PCT1components may be reused for different styles of patient interfaces. This may allow for easier manufacturing and assembly, because a large number of the same components may be produced and used in a variety of styles. The only components not used in multiple styles may be the sleeves. However, the sleeves may be easier to manufacture. Fig. 70 shows a portion of air circuit 4170 that may interface with the patient interface, while Fig. 7N shows a vent 3404 that may interchangeably replace the air circuit shown in Fig. 70, depending on the style of the patient interface.4.4 RPT DEVICE

[0362] A respiratory pressure therapy (RPT) device 4000 in accordance with one aspect of the present technology 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.4.5 AIR CIRCUIT

[0363] An air circuit 4170 in accordance with an aspect of the present technology is a conduit or a tube constructed and arranged to allow, in use, a flow of air to travel between two components such an RPT device 4000 and the patient interface 3000. 4.6 GLOSSARY

[0364] For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the following definitions may apply. In other forms of the present technology, alternative definitions may apply.4.6.1 General

[0365] Air: In certain forms of the present technology, air may be taken to mean atmospheric air, and in other forms of the present technology air may be taken to mean some other combination of breathable gases, e.g. oxygen enriched air.

[0366] 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.

[0367] 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 partialA2578192 12.0 67Ref: P2755WO1 / 506986PCT1upper airway obstruction, and decreased in the absence of indications of partial upper airway obstruction.

[0368] Leak: The word leak will be taken to be an unintended flow of air. In one example, leak may occur as the result of an incomplete seal between a mask and a patient's face. In another example leak may occur in a swivel elbow to the ambient.

[0369] Noise, vent (acoustic): Vent noise in the present document refers to noise which is generated by the flow of air through any vents such as vent holes of the patient interface.

[0370] Patient: A person, whether or not they are suffering from a respiratory condition.

[0371] Pressure: Force per unit area. Pressure may be expressed in a range of units, including cmH20, g-f / cm2 and hectopascal. 1 cmH20 is equal to 1 g-f / cm2 and is approximately 0.98 hectopascal (1 hectopascal = 100 Pa = 100 N / m2 = 1 millibar ~ 0.001 atm). In this specification, unless otherwise stated, pressure is given in units of cmH20.

[0372] Respiratory Pressure Therapy: The application of a supply of air to an entrance to the airways at a treatment pressure that is typically positive with respect to atmosphere.4.6.1.1 Materials & their properties

[0373] Hardness: Refers to durometer or indentation hardness, which is a material property measured by indentation of an indentor (e.g., as measured in accordance with ASTM D2240).• ‘Soft’ materials may include silicone or thermo-plastic elastomer (TPE), and may, e.g. readily deform under finger pressure.• ‘Hard’ materials may include polycarbonate, polypropylene, and may not e.g.readily deform under finger pressure.

[0374] 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 (orA2578192 12.0 68Ref: P2755WO1 / 506986PCT1Type A) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240.

[0375] Polycarbonate: a thermoplastic polymer of Bisphenol-A Carbonate.4.6.1.2 Mechanics

[0376] Axes:a. Neutral axis: An axis in the cross-section of a beam or plate along which there are no longitudinal stresses or strains.b. Longitudinal axis: An axis extending along the length of a shape. The axis generally passes through a centre of the shape.c. Circumferential axis: An axis oriented perpendicularly with respect to the longitudinal axis. The axis may be specifically present in pipes, tubes, cylinders, or similar shapes with a circular and / or elliptical cross section.

[0377] Deformation: The process where the original geometry of a member changes when subjected to forces, e.g. a force in a direction with respect to an axis. The process may include stretching or compressing, bending and, twisting.

[0378] Elasticity: The ability of a material to return to its original geometry after deformation.

[0379] Floppy structure or component: A structure or component that will change shape, e.g. bend, when caused to support its own weight, within a relatively short period of time such as 1 second.

[0380] Resilience: Ability of a material to absorb energy when deformed elastically and to release the energy upon unloading.

[0381] Resilient: Will release substantially all of the energy when unloaded. Includes e.g. certain silicones, and thermoplastic elastomers.

[0382] Rigid structure or component: A structure or component that will not substantially change shape when subject to the loads typically encountered in use. An example of such a use may be setting up and maintaining a patient interface in sealing relationship with an entrance to a patient's airways, e.g. at a load of approximately 20 to 30 cmH20 pressure.

[0383] 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.A2578192 12.0 69Ref: P2755WO1 / 506986PCT1

[0384] 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.

[0385] Yield: The situation when a material can no longer return back to its original geometry after deformation.4.6.1.3 Structural Elements

[0386] Compression member: A structural element that resists compression forces.

[0387] Elbow: An elbow is an example of a structure that directs an axis of flow of air travelling therethrough to change direction through an angle. In one form, the angle may be approximately 90 degrees. In another form, the angle may be more, or less than 90 degrees. The elbow may have an approximately circular cross-section. In another form the elbow may have an oval or a rectangular cross-section. In certain forms an elbow may be rotatable with respect to a mating component, e.g. about 360 degrees. In certain forms an elbow may be removable from a mating component, e.g. via a snap connection. In certain forms, an elbow may be assembled to a mating component via a one-time snap during manufacture, but not removable by a patient.

[0388] Frame: Frame will be taken to mean a mask structure that bears the load of tension between two or more points of connection with a headgear. A mask frame may be a non-airtight load bearing structure in the mask. However, some forms of mask frame may also be air-tight.

[0389] Membrane: Membrane will be taken to mean a typically thin element that has, preferably, substantially no resistance to bending, but has resistance to being stretched.

[0390] Tie (noun): A structure designed to resist tension.

[0391] Thin structures:a. Beams,i. A beam may be relatively long in one dimension compared to the other two dimensions such that the smaller dimensions are comparatively thin compared to the long dimension b. Membranes,A2578192 12.0 70Ref: P2755WO1 / 506986PCT1i. Relatively long in two dimensions, with one thin dimension.Readily deforms in response to bending forces. Resists being stretched, (might also resist compression).c. Plates & Shellsi. These may be relatively long in two directions, with one thin dimension. They may have bending, tensile, and / or compressive stiffness.

[0392] Seal: May be a noun form ("a seal") which refers to a structure, or a verb form (“to seal”) which refers to the effect. Two elements may be constructed and / or arranged to ‘seal’ or to effect ‘sealing’ therebetween without requiring a separate ‘seal’ element per se.

[0393] Shell: A shell will be taken to mean a curved, relatively thin structure having bending, tensile and compressive stiffness. For example, a curved structural wall of a mask may be a shell. In some forms, a shell may be faceted. In some forms a shell may be airtight. In some forms a shell may not be airtight.

[0394] Stiffener: A stiffener will be taken to mean a structural component designed to increase the bending resistance of another component in at least one direction.

[0395] Strut: A strut will be taken to be a structural component designed to increase the compression resistance of another component in at least one direction.

[0396] Swivel (noun): A subassembly of components configured to rotate about a common axis, preferably independently, preferably under low torque. In one form, the swivel may be constructed to rotate through an angle of at least 360 degrees. In another form, the swivel may be constructed to rotate through an angle less than 360 degrees. When used in the context of an air delivery conduit, the sub-assembly of components preferably comprises a matched pair of cylindrical conduits. There may be little or no leak flow of air from the swivel in use.4.6.2 Respiratory cycle

[0397] Apnea: According to some definitions, an apnea is said to have occurred when flow falls below a predetermined threshold for a duration, e.g. 10 seconds. An obstructive apnea will be said to have occurred when, despite patient effort, some obstruction of the airway does not allow air to flow. A central apnea will be said to have occurred when an apnea is detected that is due to a reduction in breathing effort,A2578192 12.0 71Ref: P2755WO1 / 506986PCT1or the absence of breathing effort, despite the airway being patent. A mixed apnea occurs when a reduction or absence of breathing effort coincides with an obstructed airway.4.6.3 Anatomy4.6.3.1 Anatomy of the face

[0398] Ala: the external outer wall or "wing" of each nostril (plural: alar)

[0399] Alare: The most lateral point on the nasal ala.

[0400] Alar curvature (or alar crest) point: The most posterior point in the curved base line of each ala, found in the crease formed by the union of the ala with the cheek.

[0401] (nose) Bony framework: The bony framework of the nose comprises the nasal bones, the frontal process of the maxillae and the nasal part of the frontal bone.

[0402] (nose) Cartilaginous framework: The cartilaginous framework of the nose comprises the septal, lateral, major and minor cartilages.

[0403] Columella: the strip of skin that separates the nares and which runs from the pronasale to the upper lip.

[0404] Frankfort horizontal plane: A line extending from the most inferior point of the orbital margin to the left tragion. The tragi on is the deepest point in the notch superior to the tragus of the auricle.

[0405] Lateral nasal cartilage: A generally triangular plate of cartilage. Its superior margin is attached to the nasal bone and frontal process of the maxilla, and its inferior margin is connected to the greater alar cartilage.

[0406] Lip, lower (labrale inferius): The lip extending between the subnasale and the mouth.

[0407] Lip, upper (labrale superius): The lip extending between the mouth and the supramenton.

[0408] Nares (Nostrils): Approximately ellipsoidal apertures forming the entrance to the nasal cavity. The singular form of nares is naris (nostril). The nares are separated by the nasal septum.

[0409] Naso-labial sulcus or Naso-labial fold: The skin fold or groove that runs from each side of the nose to the comers of the mouth, separating the cheeks from the upper lip.A2578192 12.0 72Ref: P2755WO1 / 506986PCT1

[0410] Naso-labial angle: The angle between the columella and the upper lip, while intersecting subnasale.

[0411] Otobasion inferior: The lowest point of attachment of the auricle to the skin of the face.

[0412] Otobasion superior: The highest point of attachment of the auricle to the skin of the face.

[0413] Pronasale: the most protruded point or tip of the nose, which can be identified in lateral view of the rest of the portion of the head.

[0414] Ridge (nasal): The nasal ridge is the midline prominence of the nose, extending from the Sellion to the Pronasale.

[0415] Sagittal plane: A vertical plane that passes from anterior (front) to posterior (rear). The midsagittal plane is a sagittal plane that divides the body into right and left halves.

[0416] Sellion: Located on the soft tissue, the most concave point overlying the area of the frontonasal suture.

[0417] Septal cartilage (nasal): The nasal septal cartilage forms part of the septum and divides the front part of the nasal cavity.

[0418] Subalare: The point at the lower margin of the alar base, where the alar base joins with the skin of the superior (upper) lip.

[0419] Subnasal point: Located on the soft tissue, the point at which the columella merges with the upper lip in the midsagittal plane.4.6.3.1 Anatomy of the skull

[0420] Frontal bone: The frontal bone includes a large vertical portion, the squama frontalis, corresponding to the region known as the forehead.

[0421] Nasal bones: The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, the "bridge" of the nose.

[0422] Occipital bone: The occipital bone is situated at the back and lower part of the cranium. It includes an oval aperture, the foramen magnum, through which the cranial cavity communicates with the vertebral canal. The curved plate behind the foramen magnum is the squama occipitalis.

[0423] Parietal bones: The parietal bones are the bones that, when joined together, form the roof and sides of the cranium.A2578192 12.0 73Ref: P2755WO1 / 506986PCT1

[0424] Temporal bones: The temporal bones are situated on the bases and sides of the skull, and support that part of the face known as the temple.

[0425] Zygomatic bones: The face includes two zygomatic bones, located in the upper and lateral parts of the face and forming the prominence of the cheek.4.6.4 Patient interface

[0426] Anti-asphyxia valve (AAV): The component or sub-assembly of a mask system that, by opening to atmosphere in a failsafe manner, reduces the risk of excessive CO2 rebreathing by a patient.

[0427] Headgear: Headgear will be taken to mean a form of positioning and stabilising structure designed to hold a device, e.g., a mask, on a head.

[0428] Plenum chamber: a mask plenum chamber will be taken to mean a portion of a patient interface having walls at least partially enclosing a volume of space, the volume having air therein pressurised above atmospheric pressure in use. A shell may form part of the walls of a mask plenum chamber.

[0429] Seal: May be a noun form ("a seal") which refers to a structure, or a verb form (“to seal”) which refers to the effect. Two elements may be constructed and / or arranged to ‘seal’ or to effect ‘sealing’ therebetween without requiring a separate ‘seal’ element per se.

[0430] Vent: (noun): A structure that allows a flow of air from an interior of the mask system, such as the plenum chamber, or conduit, or a connector to ambient air for clinically effective washout of exhaled gases. For example, a clinically effective washout may involve a flow rate of about 10 litres per minute to about 100 litres per minute, depending on the mask design and treatment pressure.4.6.5 Shape of structures

[0431] 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-A2578192 12.0 74Ref: P2755WO1 / 506986PCT1contacting (e.g. underside or inner) surface. In another example, a structure may comprise a first surface and a second surface.

[0432] To facilitate describing the shape of the three-dimensional structures and the surfaces, we first consider a cross-section through a surface of the structure at a point, p. See Fig. 3B to Fig. 3F, which illustrate examples of cross-sections at point p on a surface, and the resulting plane curves. Figs. 3B to 3F also illustrate an outward normal vector at p. The outward normal vector at p points away from the surface. In some examples we describe the surface from the point of view of an imaginary small person standing upright on the surface.4.6.5.1 Curvature in one dimension

[0433] The curvature of a plane curve at p may be described as having a sign (e.g. positive, negative) and a magnitude (e.g. 1 / radius of a circle that just touches the curve at p).

[0434] Positive curvature: If the curve at p turns towards the outward normal, the curvature at that point will be taken to be positive (if the imaginary small person leaves the point p they must walk uphill). See Fig. 3B (relatively large positive curvature compared to Fig. 3C) and Fig. 3C (relatively small positive curvature compared to Fig. 3B). Such curves are often referred to as concave.

[0435] Zero curvature: If the curve at p is a straight line, the curvature will be taken to be zero (if the imaginary small person leaves the point p, they can walk on a level, neither up nor down). See Fig. 3D.

[0436] Negative curvature: If the curve at p turns away from the outward normal, the curvature in that direction at that point will be taken to be negative (if the imaginary small person leaves the point p they must walk downhill). See Fig. 3E (relatively small negative curvature compared to Fig. 3F) and Fig. 3F (relatively large negative curvature compared to Fig. 3E). Such curves are often referred to as convex.4.6.5.1 Curvature of two dimensional surfaces

[0437] A description of the shape at a given point on a two-dimensional surface in accordance with the present technology may include multiple normal crosssections. 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. The planeA2578192 12.0 75Ref: P2755WO1 / 506986PCT1curves in Figs. 3B to 3F could be examples of such multiple cross-sections at a particular point.

[0438] Principal curvatures and directions: The directions of the normal planes where the curvature of the curve takes its maximum and minimum values are called the principal directions. In the examples of Fig. 3B to Fig. 3F, the maximum curvature occurs in Fig. 3B, and the minimum occurs in Fig. 3F, hence Fig. 3B and Fig. 3F are cross sections in the principal directions. The principal curvatures at p are the curvatures in the principal directions.

[0439] 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.

[0440] 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).

[0441] 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”).

[0442] 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.

[0443] Planar region: A region of a surface where both of the principal curvatures are zero (or, for example, zero within manufacturing tolerances).

[0444] Edge of a surface: A boundary or limit of a surface or region.

[0445] Path: In certain forms of the present technology, ‘path’ will be taken to mean a path in the mathematical - topological sense, e.g. a continuous space curve from f(0) to f(l) on a surface. In certain forms of the present technology, a ‘path’ may be described as a route or course, including e.g. a set of points on a surface. (The path for the imaginary person is where they walk on the surface, and is analogous to a garden path).

[0446] Path length: In certain forms of the present technology, ‘path length’ will be taken to mean the distance along the surface from f(0) to f(l), that is, the distance along the path on the surface. There may be more than one path between two points on a surface and such paths may have different path lengths. (The path length for the imaginary person would be the distance they have to walk on the surface along the path).A2578192 12.0 76Ref: P2755WO1 / 506986PCT1

[0447] 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’.)4.7 OTHER REMARKS

[0448] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in Patent Office patent files or records, but otherwise reserves all copyright rights whatsoever.

[0449] Unless the context clearly dictates otherwise and where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limit of that range, and any other stated or intervening value in that stated range is encompassed within the technology. The upper and lower limits of these intervening ranges, which may be independently included in the intervening ranges, are also encompassed within the technology, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the technology.

[0450] Furthermore, where a value or values are stated herein as being implemented as part of the technology, it is understood that such values may be approximated, unless otherwise stated, and such values may be utilized to any suitable significant digit to the extent that a practical technical implementation may permit or require it.

[0451] Furthermore, “approximately”, “substantially”, “about”, or any similar term used herein means + / - 5-10% of the recited value.

[0452] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of theA2578192 12.0 77Ref: P2755WO1 / 506986PCT1present technology, a limited number of the exemplary methods and materials are described herein.

[0453] When a particular material is identified as being used to construct a component, obvious alternative materials with similar properties may be used as a substitute. Furthermore, unless specified to the contrary, any and all components herein described are understood to be capable of being manufactured and, as such, may be manufactured together or separately.

[0454] It must be noted that as used herein and in the appended claims, the singular forms "a", "an", and "the" include their plural equivalents, unless the context clearly dictates otherwise.

[0455] All publications mentioned herein are incorporated herein by reference in their entirety to disclose and describe the methods and / or materials which are the subject of those publications. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present technology is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates, which may need to be independently confirmed.

[0456] 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.

[0457] The subject headings used in the detailed description are included only for the ease of reference of the reader and should not be used to limit the subject matter found throughout the disclosure or the claims. The subject headings should not be used in construing the scope of the claims or the claim limitations.

[0458] 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 isA2578192 12.0 78Ref: P2755WO1 / 506986PCT1not 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.

[0459] It is therefore to be understood that numerous modifications may be made to the illustrative examples and that other arrangements may be devised without departing from the spirit and scope of the technology.A2578192 12.0 79

Claims

1. Ref: P2755WO1 / 506986PCT15 CLAIMS1. A decoupling structure configured for use with a patient interface, the decoupling structure configured to receive at least a portion of a downstream end of an air circuit delivering a flow of breathable gas at a positive pressure to the patient interface and including:a body at least partially defining an interior passage;wherein the body has a first end and a second end, the interior passage extending between the first end and the second end;wherein the body is configured to receive at least the portion of the downstream end of the air circuit at or within the second end of the body; wherein the portion of the downstream end of the air circuit is received within the second end of the body such that a gap is provided between an external surface of the end of the air circuit and an interior surface forming at least part of the interior passage of the body, the gap defining part of a flow path for a vent flow of gases from the patient interface.

2. The decoupling structure as claimed in claim 1, wherein the second end of the body is angled relative to the first end of the body.

3. The decoupling structure as claimed in claim 1 or claim 2, wherein the body and the patient interface comprise complementary snap-fit fittings.

4. The decoupling structure as claimed in claim 3, wherein the complementary snap-fit fittings are arranged such that when engaged, the body of the decoupling structure is able to rotate relative to the patient interface.

5. The decoupling structure as claimed in claim 4, wherein the portion of the downstream end of the air circuit is concentrically received within the second end of the body of the decoupling structure.A2578192 12.0 80Ref: P2755WO1 / 506986PCT16. The decoupling structure as claimed in any one of claims 1 to 5, wherein the body comprises a flange extending inwardly with respect to the interior surface of the body.

7. The decoupling structure as claimed in claim 6, wherein the flange has an inner circumference defining a bore that receives a connection port configured to engage with the downstream end of the air circuit.

8. The decoupling structure as claimed in claim 6, wherein the flange has an inner circumference defining a bore that receives the downstream end of the air circuit.

9. The decoupling structure as claimed in any one of claims 6 to 8, wherein the flange has a downstream side facing the patient interface and an upstream side facing the downstream end of the air circuit.

10. The decoupling structure as claimed in any one of claims 6 to 9, wherein the flange includes one or more apertures extending between the downstream side and the upstream side.

11. The decoupling structure as claimed in claim 10, wherein the one or more apertures are communicative with the gap provided between the external surface of the end of the air circuit and the interior surface forming at least part of the interior passage of the body and forms part of the flow path for the vent flow of gases.

12. The decoupling structure as claimed in claim 10 or claim 11, wherein the decoupling structure comprises a diffuser element for diffusing the vent flow of gases.

13. The decoupling structure as claimed in claim 12, wherein the diffuser element is structured as an annular ring substantially complementary in profile to the flange of the body.A2578192 12.0 81Ref: P2755WO1 / 506986PCT114. The decoupling structure as claimed in claim 13, wherein the diffuser element is positioned between the upstream side of the flange of the body and a connector configured to engage with the downstream end of the air circuit such that the diffuser element is in the path of the vent flow of gases from the patient interface.

15. The decoupling structure as claimed in claim 13, wherein the diffuser is positioned between the upstream side of the flange and the downstream end of the air circuit such that the diffuser element is in the path of the vent flow of gases from the patient interface .

16. A patient interface configured to receive a flow of breathable gas having a positive pressure of at least 4 cmH20, the patient interface including a decoupling structure as claimed in any one of claims 1 to 15.

17. A patient interface for treatment of sleep disordered breathing, the patient interface comprising:a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure, the plenum chamber including at least one plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient;a seal-forming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways, the seal-forming structure having a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares, the seal-forming structure being constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use;a positioning and stabilising structure to provide a force to hold the seal -forming structure in a therapeutically effective position on the patient’sA2578192 12.0 82Ref: P2755WO1 / 506986PCT1head, the positioning and stabilising structure comprising a frame and headgear connected to the frame;wherein the patient interface comprises a cushion module forming the seal-forming structure and at least partially forming the plenum chamber, the cushion module being configured to connect to the frame in use;wherein the frame comprises a frame opening and the flow of air at the therapeutic pressure flows through the frame opening into the cushion module;wherein the cushion module comprises a cushion module connection portion defining an anterior opening and the frame comprises a frame connection portion, wherein the cushion module connection portion comprises a perimeter configured to sealingly engage a perimeter of the frame connection portion to fluidly connect the cushion module to the frame in use, the perimeter of the cushion module connection portion and the perimeter of the frame connection portion being correspondingly shaped perimeters;wherein the cushion module and frame comprise at least one pair of complementary features in addition to the correspondingly shaped perimeters, the at least one pair of complementary features preventing incorrect orientation of the cushion module with respect to the frame during assembly of the cushion module to the frame.

18. The patient interface of claim 17, wherein the correspondingly shaped perimeters of the cushion module and frame are circular perimeters.

19. The patient interface of claim 17 or claim 18, wherein the cushion module connection portion comprises an inwardly facing lip and the frame connection portion comprises an outwardly facing channel structured to receive the inwardly facing lip.

20. The patient interface of claim 19, wherein the seal -forming structure is formed from a first material and the inwardly facing lip is formed from a second material having a greater hardness than the first material.A2578192 12.0 83Ref: P2755WO1 / 506986PCT121. The patient interface of claim 20, wherein both the first material and the second material are elastomeric materials.

22. The patient interface of claim 21, wherein the first material is a first silicone material and the second material is a second silicone material, the second silicone material having a greater durometer hardness than the first silicone material.

23. The patient interface of any one of claims 17-22, wherein the at least one pair of complementary features comprises a protrusion and a recess, one of the protrusion and the recess being provided to the frame and the other of the protrusion and the recess being provided to the cushion module.

24. The patient interface of any one of claims 17-22, wherein the at least one pair of complementary features comprises a superior pair of complementary features comprising a superior protrusion of the frame and a correspondingly shaped superior portion of the cushion module configured to receive the superior protrusion.

25. The patient interface of claim 24, wherein the correspondingly shaped superior portion of the cushion module is a recess.

26. The patient interface of claim 25, wherein the recess is recessed with respect to an exterior surface of the cushion module.

27. The patient interface of any one of claims 17-26, wherein the at least one pair of complementary features comprises an inferior pair of complementary features comprising an inferior protrusion of the frame and a correspondingly shaped inferior portion of the cushion module configured to receive the inferior protrusion.

28. The patient interface of claim 27, wherein the correspondingly shaped inferior portion is defined between a pair of inferior protrusions of the cushion module,A2578192 12.0 84Ref: P2755WO1 / 506986PCT1the inferior protrusions of the cushion module being positioned on respective lateral sides of the inferior protrusion of the frame.

29. The patient interface of claim 28, wherein the inferior protrusions are provided internally to the cushion module.

30. A frame for a patient interface for treatment of sleep disordered breathing, the frame comprising:a central portion configured to connect directly or indirectly to a cushion module of the patient interface, the cushion module at least partially forming a plenum chamber of the patient interface and comprising a sealforming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways;a pair of arms extending from the central portion on respective lateral sides thereof, each arm comprising:a medial portion connected at a medial end thereof to the central portion;a superior portion extending at least partially superiorly from a lateral end of the medial portion, the superior portion comprising a superior headgear connector at a superior end thereof; andan inferior portion extending at least partially inferiorly from the lateral end of the medial portion, the inferior portion comprising an inferior headgear connector at an inferior end thereof;a pad positioned to engage the user’s head in use, the pad forming at least part of the superior portion, the inferior portion and a junction between the superior portion, the inferior portion and the medial portion;a rigidising material attached to the pad in at least the superior portion, the inferior portion and the junction, the rigidising material comprising a junction rigidising portion located at the junction, aA2578192 12.0 85Ref: P2755WO1 / 506986PCT1superior end rigidising portion located at or proximate the superior end of the superior portion, and an inferior end rigidising portion located at or proximate the inferior end of the inferior portion, the thickness of the rigidising material being greater in the junction rigidising portion than in the superior end rigidising portion and / or the inferior end rigidising portion.

31. The frame of claim 30, wherein the thickness of the rigidising material is greater in the junction rigidising portion than in both the superior end rigidising portion and the inferior end rigidising portion.

32. The frame of claim 30 or claim 31, wherein the junction rigidising portion extends from the junction along at least half of the length of the superior portion.

33. The frame of claim 32, wherein the junction rigidising portion extends from the junction along more than half of the length of the superior portion.

34. The frame of any one of claims 30-33, wherein the junction rigidising portion extends from the junction along at least half of the length of the inferior portion.

35. The frame of claim 34, wherein the junction rigidising portion extends from the junction along more than half of the length of the inferior portion.

36. The frame of any one of claims 30-35 wherein the rigidising material has a thickness within the range of 1.5-2mm in the junction rigidising portion.

37. The frame of any one of claims 30-36, wherein the rigidising material has a thickness within the range of 1.3-1.7mm in the superior end rigidising portion38. The frame of any one of claims 30-37, wherein the rigidising material has a thickness within the range of 1.3-1.7mm in the inferior end rigidising portion.A2578192 12.0 86Ref: P2755WO1 / 506986PCT139. The frame of any one of claims 30-38, wherein the rigidising material comprises a posterior edge rigidising portion provided proximate a posterior edge of the pad, the rigidising material having a lesser thickness in the posterior edge rigidising portion than in the junction rigidising portion.

40. The frame of claim 39, wherein the rigidising material has a lesser thickness in the posterior edge rigidising portion than in the superior end rigidising portion.

41. The frame of claim 39 or claim 40, wherein the rigidising material has a lesser thickness in the posterior edge rigidising portion than in the inferior end rigidising portion.

42. The frame of any one of claims 39-41, wherein the rigidising material has a thickness within the range of 0.4-lmm in the posterior edge rigidising portion.

43. The frame of any one of claims 30-42, wherein the rigidising material is also attached to the pad in the medial portion, the rigidising material comprising a medial rigidising portion in the medial portion located medially of the junction rigidising portion.

44. The frame of claim 43, wherein the thickness of the rigidising material is greater in the junction rigidising portion than in the medial rigidising portion.

45. The frame of claim 43 or claim 44, wherein the rigidising material has a thickness within the range of 1.3-1.7mm in the medial rigidising portion.

46. The frame of any one of claims 43-45, wherein in each arm, the rigidising material extends medially away from the pad to form a medial end of the arm.

47. The frame of any one of claims 30-46, wherein the rigidising material is connected to the central portion of the frame.

48. The frame of claim 47, wherein the rigidising material is integrally formed with the central portion of the frame.A2578192 12.0 87Ref: P2755WO1 / 506986PCT149. The frame of any one of claims 30-48, wherein the rigidising material is overmoulded to the pad.

50. A cushion module for a patient interface for treatment of sleep disordered breathing, the cushion module defining a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH20 above ambient air pressure, the cushion module comprising:a seal-forming structure constructed and arranged to form a seal with a region of the patient’s face surrounding an entrance to the patient’s airways, the seal-forming structure having a hole therein such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient’s nares in use, the seal-forming structure being constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient’s respiratory cycle in use, the seal-forming structure comprising:a nasal ridge portion positioned to seal to the patient’s nasal ridge in use;an inferior portion, wherein the inferior portion is positioned to seal to the patient’s lip superior or wherein the inferior portion is positioned to seal to the patient’s face against or inferior to the patient’s lip inferior;a pair of lateral patient-facing portions each connecting between the nasal ridge portion and the inferior portion on a respective lateral side of the cushion module;a pair of flaps each extending medially from a respective one of the lateral patient-facing portions and each positioned to engage a respective lateral side of the patient’s nose;wherein the seal-forming structure has a greater thickness in each of the pair of flaps than in the nasal ridge portion and / or the inferior portion.A2578192 12.0 88Ref: P2755WO1 / 506986PCT151. The cushion module of claim 50, wherein the seal-forming structure has a greater thickness in each of the pair of flaps than in the nasal ridge portion.

52. The cushion module of claim 50 or claim 51, wherein the seal-forming structure has a greater thickness in each of the pair of flaps than in the inferior portion.

53. The cushion module of any one of claims 50-52, wherein the seal-forming structure has a thickness of between 0.2-0.3mm in the nasal ridge portion.

54. The cushion module of any one of claims 50-53, wherein the seal-forming structure has a thickness of between 0.2-0.3mm in the inferior portion.

55. The cushion module of any one of claims 50-54, wherein the seal-forming structure has a thickness between 0.3-0.5mm in each of the flaps.

56. The cushion module of any one of claims 50-55, wherein the seal-forming structure has a thickness between 0.3-0.4mm in each of the flaps.

57. The cushion module of any one of claims 50-56, wherein the inferior portion is positioned to seal to the patient’s lip superior.

58. The cushion module of any one of claims 50-57, wherein the seal-forming structure comprises a pair of inferolateral portions each in an inferior and lateral position on a respective lateral side of the seal-forming structure, each positioned laterally of the inferior portion of the seal-forming structure, the seal-forming structure having a greater thickness in the inferolateral portions than in the inferior portion.

59. The cushion module of claim 58, wherein each of the inferolateral portions increases in thickness away from the hole of the seal-forming structure.A2578192 12.0 89Ref: P2755WO1 / 506986PCT160. The cushion module of claim 58 or 59, wherein the seal-forming structure comprises a pair of superolateral portions each on a respective lateral side of the seal-forming structure, each superolateral portion being positioned superiorly of the inferolateral portions and inferiorly of the nasal ridge portion, at least a portion of each superolateral portion being thicker than the nasal ridge portion.

61. The cushion module of claim 60, wherein each of the superolateral portions increases in thickness away from the hole of the seal-forming structure.

62. The cushion module of claim 60 or 61, wherein each of the superolateral portions is adjacent a respective one of the pair of flaps.

63. The cushion module of any one of claims 60-62, wherein the seal-forming structure comprises a pair of lateral portions each on a respective lateral side of the seal-forming structure, each lateral portion being positioned at least partially inferior to a respective one of the superolateral portions and at least partially superior to a respective one of the inferolateral portions, the lateral portions being thicker than the inferolateral portions and / or the superolateral portions64. The cushion module of any one of claims 60-63, wherein the seal-forming structure comprises a pair of superior stiffened portions each positioned on a respective lateral side of the seal-forming structure between the nasal ridge portion and a respective one of the superolateral portions, the seal-forming structure having a greater thickness in each of the superior stiffened portions than in the nasal ridge portion.

65. The cushion module of claim 64, wherein a medial portion of each of the superior stiffened portions is greater in thickness than an adjacent portion of the respective superolateral portion.A2578192 12.0 90Ref: P2755WO1 / 506986PCT166. The cushion module of claim 64 or claim 65, wherein each of the superior stiffened portions increases in thickness away from the hole of the sealforming structure.A2578192 12.0 91

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