Patient interface

Abstract

A non-invasive patient interface is disclosed. The non-invasive patient interface is configured to seal about the mouth and nares of a patient. The patient interface includes an outer wall defining an interior volume which includes a first chamber to communicate gas with the mouth and a second chamber to communicate gas with the nares. The patient interface includes a dividing wall that separates the first chamber from the second chamber. The dividing wall includes a first resilient region that is linked to the distal side of the outer wall. A second resilient region is linked to the proximal side of the outer wall and a deformation panel links the first and second resilient regions. The patient interface includes one or more flow directors which enable gas to flow into the second chamber from the first chamber. At least part of the first resilient region is at a level that is lower than a level of at least part of the second resilient region, having regard to a generally upright orientation of the patient interface.

Description

[0001] PATIENT INTERFACE

[0002] TECHNICAL FIELD

[0003] The present invention relates to a patient interface for delivering respiratory gas to a patient. In particular, the present invention relates to a non-invasive patient interface.

[0004] BACKGROUND

[0005] One current treatment for respiratory diseases, such as thoracic restrictive diseases, acute respiratory failure, advanced neuromuscular diseases, chronic obstructive pulmonary disease (COPD - which includes emphysema, refractory asthma and chronic bronchitis), is non-invasive ventilation (NIV). There is some evidence to suggest that NIV therapy may be useful for assisting respiration after intubation, including reducing the chances of re-intubation. The NIV treatment applies a positive airway pressure to the lungs throughout the inhalation and exhalation cycle so as to splint the airways open. This improves the flow of respiratory gas into and out of the lungs.

[0006] However, one side effect of the positive pressure applied in current NIV treatments is that the therapy pressures applied can make patients uncomfortable and, therefore, less willing to undergo the treatment. A follow-on effect of the positive pressure is that it requires the patient interface to be secured firmly to the patient to avoid leakages and, thereby ensure that the pressure is maintained in the patient interface and the respiratory system. Such firm application of the interface can cause pressure sores, particularly for patients that are semi-conscious or unconscious and, therefore, are unable to provide feedback on any soreness caused by the pressure of the patient interface on their skin.

[0007] The NIV treatment gives rise to two challenges, namely compliance (the extent to which patients are willing to submit to the treatment) and pressure sores. In addition to these challenges, a further challenge for patients with obstructive respiration diseases is flushing carbon dioxide out of anatomical dead space. Specifically, the end of the exhalation cycle is characterised by a reduction in pressure of the exhaled respiratory gas. This means that the carbon dioxide-loaded respiratory gas remains in the throat, nose and mouth of the patient and is pulled back into the lungs at the commencement of the inhalation cycle. Replacing the carbon dioxide-loaded respiratory gas in these regions with respiratory gas that includes higher levels of oxygen than the carbon dioxide-loaded respiratory gas therefore assists patients in achieving sufficient respiration. It is desirable to provide a patient interface that improves patient comfort and that reduces pressure sores.

[0008] It is also desirable to provide a patient interface that assists with flushing anatomical dead space.

[0009] SUMMARY OF THE DISCLOSURE

[0010] Aspects of the patient interface will now be described. However, it will be appreciated that additional aspects may be defined by combining the features of two or more separate aspects.

[0011] According to a first aspect, there is provided a non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :

[0012] • an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares, the outer wall including a proximal side that includes a patient-contact surface and a distal side at an opposite side of the outer wall to the proximal side; and

[0013] • a dividing wall that separates the first chamber from the second chamber, the dividing wall includes a first resilient region that is linked to the distal side of the outer wall, a second resilient region that is linked to the proximal side of the outer wall and a deformation panel linking the first and second resilient regions; and

[0014] • one or more flow directors which enable gas to flow into the second chamber from the first chamber and which flow directors are configured to direct the gas flow towards the one or more nare openings; and wherein at least part of the first resilient region is at a level that is lower than a level of at least part of the second resilient region, having regard to a generally upright orientation of the patient interface.

[0015] The non-invasive patient interface is configured to deliver pressurised respiratory gas to a patient. The first resilient region and the deformation panel may meet at a level that is lower than the level where the second resilient region and the deformation panel meet. The first resilient region and the deformation panel may meet at a level that is below a level where the second resilient region and the deformation panel meet at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to a generally upright orientation of the patient interface.

[0016] The first resilient region and the deformation panel may meet at a level that is below, having regard to a generally upright orientation of the patient interface, the level where the second resilient region and the deformation panel meet at each respective lateral location between laterally outer-most edges of the one or more nare openings.

[0017] The second resilient region may be include the one or more flow directors.

[0018] At least part of the first resilient region may decrease in wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

[0019] At least part of the first resilient region may include a generally constant wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

[0020] At least part of the first resilient region may increase in wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

[0021] The first resilient region may include a second chamber surface exposed to the second chamber. The second resilient region may include a second chamber surface exposed to the second chamber.

[0022] At least at a vertical mid-plane through the patient interface in the proximal distal direction, having regard to an upright orientation of the patient interface, the second chamber surface of the first resilient region may be inclined at an obtuse angle relative to the orientation of the deformation panel at a location where they meet.

[0023] A centreline in the proximal-distal direction across the second chamber surface of the second resilient region may be parallel to or within + / - 20° of a centreline in the proximal-distal direction across the second chamber surface of the first resilient region. A centreline in the proximal-distal direction across the second chamber surface of the second resilient region may be parallel to or within + / - 10° of a centreline in the proximal-distal direction across the second chamber surface of the first resilient region.

[0024] A vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel may be constant along the width of the deformation panel.

[0025] The vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel may vary along the width of the deformation panel.

[0026] The vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel may decrease in a direction laterally outwardly from a centreline in the proximal-distal direction through the first resilient region.

[0027] The patient interface may include a seal member and a housing which together define the outer wall.

[0028] The seal member and the housing may be formed from the same or different materials. The housing may be formed of a harder material than the seal member. The seal member may be formed of an elastomer and the housing may be formed of a plastic. The seal member may be formed of silicone and the housing may be formed of polycarbonate.

[0029] The seal member may include a first distal opening in the first chamber which is defined by a first rim.

[0030] The seal member may include a second distal opening in the second chamber.

[0031] The second distal opening may be defined by an upper rim portion and a lower rim portion which meet at respective lateral edges, having regard to a generally upright orientation of the patient interface.

[0032] The seal member may include the dividing wall.

[0033] The dividing wall may be integrally formed with the seal member. The first distal opening may extend laterally beyond the lateral edges of the second distal opening.

[0034] At least part of the first resilient region may meet the lower rim portion.

[0035] The first resilient region may include a lateral profile that follows the contour of the lower rim portion between the lateral edges of the second distal opening.

[0036] The first resilient region may include a central region between the lateral edges of the second distal opening.

[0037] The first resilient region may include lateral regions that are laterally adjacent to the central region.

[0038] The second chamber surface of the first resilient region in the central region is inclined relative to the deformation panel at an angle that is less than the angle between the deformation panel and the lateral regions of the first resilient region.

[0039] Part of the central region may include a cross-sectional shape in the lateral direction that is U-shaped or W-shaped.

[0040] The proximal side of the outer wall may include a lip superior wall portion between the one or more nare openings and the one or more oral openings.

[0041] The lip superior wall portion may be configured to contact a patient's lip superior between the patient's nares and mouth in use.

[0042] The lip superior wall portion may be defined laterally between the laterally outer-most edges of the one or more nare openings.

[0043] The second resilient region may link to the proximal side of the outer wall at least in part at the lip superior wall portion.

[0044] The second resilient region may meet the proximal side of the outer wall partly at the lip superior wall portion and partly laterally beyond the lip superior wall portion. The second resilient region may meet the proximal side of the outer wall at the lip superior wall portion closer to the one or more nare openings that the one or more oral openings.

[0045] The second resilient region may meet the lip superior wall portion along a line that is spaced from the one or more nare openings by a distance that is in the range of 1 to 4 times the wall thickness of the second resilient region.

[0046] The deformation panel may extend laterally beyond the second resilient region.

[0047] The dividing wall may include a forward panel that links to the distal side of the outer wall and is distal of the deformation panel.

[0048] The forward panel may include the first resilient region.

[0049] The dividing wall may include a rearward panel that links to the proximal side of the outer wall and is proximal of the deformation panel.

[0050] The rearward panel may include the second resilient region.

[0051] The forward and rearward panels may meet along a notional line that extends laterally beyond the deformation panel to the outer wall.

[0052] The notional line may be contiguous with the link between the forward panel and the deformation panel.

[0053] The second resilient region of the rearward panel may link with the deformation panel.

[0054] The distal end of the second resilient region may include a curved shape in the plane of the rearward panel.

[0055] The link between the deformation panel and the rearward panel may at least partly follow the curved shape of the distal end of the second resilient region.

[0056] The deformation panel may extend away from the distal end of the second resilient region with a similar curved shape as at the distal end second resilient region. The second resilient region may include a wall thickness that is greater than the wall thickness of the remainder of the rearward panel.

[0057] The rearward panel may include a wall thickness that is greater than a wall thickness of the deformation panel.

[0058] The rearward panel may meet the outer wall along a line at a level within a notional band defined between the lowest level of the one or more nare openings and uppermost level of the one or more oral openings.

[0059] Part of the first resilient region may meet the outer wall outside of the notional band and another part of the first resilient region may meet the outer wall within the notional band.

[0060] The first resilient region may meet the outer wall adjacent to part of the contour of the first rim laterally beyond the lateral edges of the second distal opening.

[0061] The first resilient region that is laterally beyond the lateral edges of the second distal opening may meet with the outer wall within the notional band.

[0062] The second resilient region may include a uniform wall thickness.

[0063] The second resilient region may include non-uniform wall thickness.

[0064] The wall thickness of the second resilient region may be greater than the wall thickness of the deformation panel.

[0065] The second resilient region may include a transition portion that tapers in wall thickness to the wall thickness of the remainder of the rearward panel.

[0066] The transition portion may link the second resilient region to the deformation panel.

[0067] The transition portion may define a U-shape in the plane of the rearward panel.

[0068] The transition portion may include a U-shape when viewed from the first chamber or the second chamber. The transition portion may include first portions positioned laterally outwardly of the flow directors and may include a distally extending curve portion joining the first portions.

[0069] The first portions may be parallel to each other.

[0070] The first portions may extend from the lip superior wall portion.

[0071] The first portions may extend from the outer wall at locations laterally outwardly from the patient engagement-portion.

[0072] The one or more flow directors may be within a footprint of the second resilient region.

[0073] The one or more flow directors may be partly within a footprint of the second resilient region.

[0074] The one or more flow directors may be spaced from the lip superior wall portion.

[0075] The one or more flow directors may be spaced from the transition portion.

[0076] The deformation panel may include cross-section with a straight section and a bend and the forward panel meets the straight section and rearward panel meets the bend.

[0077] The first resilient region may decrease in wall thickness in the proximal direction.

[0078] Part of the first resilient region may decrease in wall thickness in the proximal direction.

[0079] A portion of the first resilient region extending proximally of the lower rim portion of the second distal opening may decrease in wall thickness in the proximal direction.

[0080] In a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the cross-section of the first resilient region may decrease in wall thickness in the proximal direction.

[0081] The first resilient region may be inclined downwardly, having regard to an upright orientation of the patient interface, from the deformation panel to the distal side of the outer wall. At least part of the second chamber surface of the first resilient region may be inclined downwardly, having regard to an upright orientation of the patient interface, from the deformation panel to the outer wall.

[0082] At least part of the second chamber surface of the second resilient region may be inclined downwardly, having regard to an upright orientation of the patient interface, from the lip superior wall portion toward the deformation panel.

[0083] At least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the second chamber surface of the first resilient region is inclined upwardly in the proximal-distal direction from the deformation panel to the outer wall.

[0084] At least part of the second chamber surface of the first resilient region may meet the outer wall at a position that is spaced upwardly, having regard to an upright orientation of the patient interface, from where the second chamber surface of the first resilient region meets the deformation panel.

[0085] At least part of the second chamber surface of the first resilient region may meet the outer wall at a position that is spaced upwardly, having regard to an upright orientation of the patient interface, from where a laterally aligned portion of the second chamber surface of the first resilient region meets the deformation panel.

[0086] The second resilient region may be spaced from the deformation panel.

[0087] The wall thickness of at least part of the rearward panel between the second resilient region and the deformation panel may decrease in the direction from the second resilient region to the deformation panel.

[0088] At least part of the deformation panel may include a cross-section with a curved segment which links with the first resilient region.

[0089] The first resilient region may include a first chamber surface that is exposed to the first chamber.

[0090] A curvature of at least part of the first chamber surface of the first resilient region may be contiguous with the curvature of the curved segment. At least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the deformation panel may meet the second chamber surface of the first resilient region at a location that is at or above the level of an upper-most portion of the one or more oral openings.

[0091] At least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the deformation panel may meet the second chamber surface of the first resilient region below the level of an upper-most portion of the one or more oral openings.

[0092] The bend in the deformation panel may be an inflection point in the dividing wall between the first and second resilient regions.

[0093] The wall thickness of the dividing wall between the second resilient region and the deformation panel may be less than the wall thickness of the second resilient region to enable the inflection point to shift proximally toward the second resilient region when the second resilient region advances in a distal direction relative to the first resilient region.

[0094] The vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be more than half of the vertical dimension of the lip superior wall portion, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0095] The vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be more than three-quarters of the vertical dimension of the lip superior wall portion, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0096] The vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be more than the vertical dimension of the lip superior wall portion, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0097] The vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be in the range of 80-120% of the vertical dimension of the lip superior wall portion, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0098] The vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be more than the vertical spacing between the upper and lower rim portions of the second distal opening, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0099] According to a second aspect, there is provided a non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :

[0100] • an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and

[0101] • a dividing wall that separates the first chamber from the second chamber, the dividing wall includes a first resilient region that is linked to a distal portion of the outer wall, a second resilient region that is linked to a proximal portion of the outer wall and a deformation panel linking the first and second resilient regions; and

[0102] • one or more flow directors which enable gas to flow into the second chamber from the first chamber and which flow directors are configured to direct the gas flow towards the one or more nare openings; and wherein at least part of the dividing wall is curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface. The dividing wall may be curved downwardly in a laterally outward direction across substantially its entire length in a proximal-distal direction, having regard to an upright orientation of the patient interface.

[0103] At least part of the dividing wall may be curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the flow directors.

[0104] At least part of the dividing wall may be curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the first resilient region.

[0105] At least part of the dividing wall may be curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the second resilient region.

[0106] At least part of the dividing wall may be curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the lateral edges of the second distal opening.

[0107] At least part of the dividing wall may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0108] Part of the dividing wall may meet the outer wall at a level that is below a lowermost level of the lip superior wall portion, having regard to an upright orientation of the patient interface.

[0109] Part of the dividing wall may meet the outer wall at a level that is below a level more than one-third of the distance between the upper-most and lower-most rim portions of the one or more oral openings from the upper-most rim portion, having regard to an upright orientation of the patient interface.

[0110] Part of the dividing wall may meet the outer wall at a level that is approximately half the distance between the upper-most and lower-most rim portions of the one or more oral openings, having regard to an upright orientation of the patient interface. Part of the dividing wall may meet the outer wall at a level that is below a level that is half the distance between the upper-most and lower-most rims of the one or more oral opening, having regard to an upright orientation of the patient interface.

[0111] Part of the dividing wall may meet the outer wall at a level that is below a lower-most level of the first resilient region, having regard to an upright orientation of the patient interface.

[0112] The dividing wall may form an arc when viewed from the first distal opening.

[0113] In the lateral direction, the forward panel may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0114] In the lateral direction, the rearward panel may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0115] The rearward panel may have a thickened rib that follows the curve of the rearward panel.

[0116] The thickened rib may extend laterally to either side of the one or more flow directors.

[0117] The thickened rib may project from a second chamber surface of the rearward panel into the second chamber. The thickened rib may project into the first chamber and into the second chamber from the rearward panel.

[0118] In the lateral direction, the deformation panel may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0119] In the lateral direction, the rearward panel and the deformation panel may be curved downwardly from a vertical mid-plane through the patient interface in the proximal- distal direction, having regard to an upright orientation of the patient interface, and the second resilient region may comprise the thickened rib extending laterally to either side of the one or more flow directors, the thickened rib may project into the first chamber and into the second chamber from the rearward panel. At least parts of the first resilient region that are laterally beyond the first distal opening may meet with the outer wall at a level that is below the level of the central region of the first resilient region, having regard to an upright orientation of the patient interface.

[0120] The second resilient region may include one or more flow directors.

[0121] The one or more flow directors may include a rim.

[0122] The one or more flow directors may include a passage through the second resilient region.

[0123] The first resilient region may meet the distal side of the outer wall along a contour that at least partly follows the first rim of the first distal opening.

[0124] The first resilient region may meet the distal side of the outer wall along a contour that follows the lower rim of the second distal opening.

[0125] Each flow director may have a first opening to the first chamber and a second opening to the second chamber.

[0126] According to a third aspect, there is provided a non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :

[0127] • an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and

[0128] • a dividing wall that separates the first chamber from the second chamber, and wherein the outer wall includes a seal member, a first housing connected to the seal member to form part of the outer wall and a second housing connected to the seal member to form part of the outer wall.

[0129] The first housing may form part of the outer wall associated with the first chamber. The second housing may form part of the outer wall associated with the second chamber.

[0130] The seal member may be permanently connected to the first housing. The connection may be by, for example, over-moulding, adhering or welding.

[0131] The seal member may be permanently connected to the second housing. The connection may be by, for example, over-moulding, adhering or welding.

[0132] The second housing may be adhered, welded or mechanically fastened to the seal member.

[0133] The second housing may be connected to the seal member by elastically stretching the seal member over a retaining feature of the second housing.

[0134] The second housing may be removably joined to the seal member.

[0135] The second housing may be removably joined to the first housing.

[0136] The second housing may comprise two components that join to one another.

[0137] The seal member may be permanently joined to one of the second housing components (by for example over-moulding, adhering or welding) and the other second housing component is configured to join to the permanently joined component.

[0138] A part of the seal member may be clamped between the two components of the second housing when the two components are joined.

[0139] The two components of the second housing may be removably joined to one another.

[0140] The two components of the second housing may be joined by one or more clips, one or more magnets or a friction fit.

[0141] The dividing wall may include a first resilient region that is linked to a distal portion of the outer wall, a second resilient region that is linked to a proximal portion of the outer wall and a deformation panel connecting between the first and second resilient regions. The patient interface may include one or more flow directors which enable gas to flow into the second chamber from the first chamber. The flow directors may be configured to direct the gas flow towards the one or more nare openings.

[0142] The first housing may be below the second housing, having regard to a generally upright orientation of the patient interface.

[0143] The first housing and the second housing are spaced apart by part of the seal member.

[0144] The part of the seal member spacing apart the first and second housing may be a transom which is part of the outer wall.

[0145] The first resilient region may extend in the proximal direction from at least part of the transom.

[0146] Part of the first resilient region follows the contour of the lower rim portion.

[0147] The first housing and the second housing have the same lateral dimension between their respective laterally outer-most points.

[0148] The lateral dimension between the laterally outer-most points of the second housing may be within + / -20° / o of the lateral dimension between the laterally outer-most points of the first housing.

[0149] The first housing includes an opening for delivery of respiratory gas into the first chamber.

[0150] The opening includes key formations for coupling a mask frame or respiratory gas conduit to the first housing.

[0151] An upper portion of the first housing above a notional laterally extending line between the laterally outer-most parts of the first housing may have a radius of curvature that is less than a radius of curvature of a basal portion below the notional laterally extending line.

[0152] At least part of the upper portion follows the first resilient region along the outer wall. The first housing includes perimeter formations that enable over-moulding by a material that forms the seal member.

[0153] The first housing has a lateral width that is greater than the lateral width of the one or more oral openings.

[0154] The second housing includes an outlet for exhausting gas from the second chamber.

[0155] The outlet may include one or more openings for exhausting respiratory gas.

[0156] The outlet may include a bias vent.

[0157] The second housing may be co-operable with the upper rim portion and the lower rim portion of the second distal opening to form a seal between the second housing and the second distal opening.

[0158] The second housing and the upper rim portion and the lower rim portion of the second distal opening may include co-operable seal-forming formations.

[0159] The second housing may include an outlet panel and a fastening bracket which are co- operable to form a seal between the second housing and the second distal opening.

[0160] The outlet panel and the fastening bracket may be co-operable to form a seal against the second rim.

[0161] The second housing may be connected to the seal member by clamping the seal member between the outlet panel and the fastening bracket of the second housing.

[0162] The upper rim portion and the lower rim portion include a rim profile that complements a seal formation on the outlet panel or the fastening bracket.

[0163] The rim profile includes a flange with a bead.

[0164] The flange includes a first side from which the bead projects.

[0165] The flange includes a second side opposite to the first side. The seal formation on the outlet panel includes a bevel that is shaped to contact the flange and the bead.

[0166] The bevel includes a perimeter surface and an adjacent contact surface.

[0167] The flange contacts the perimeter surface and the bead contacts the adjacent contact surface.

[0168] The outlet panel contacts the second side of the flange and the perimeter surface of the fastening bracket contacts the first side of the flange.

[0169] The outlet panel may include snap-fit fingers and the fastening bracket may include receiving formations that interact with the snap-fit fingers.

[0170] The receiving formations may include one or more windows through which the snap-fit fingers can pass.

[0171] The outlet panel and the fastening bracket may be connectable by an interference fit.

[0172] The outlet panel and the fastening bracket may be connectable by co-operable mechanical or magnetic formations.

[0173] The rim profile may be compressed between the outlet panel and the fastening bracket.

[0174] The outlet panel may include one or more outlets for exhausting respiratory gas.

[0175] At least part of the second chamber surface of the first resilient region at a vertical midplane through the patient interface, having regard to an upright orientation of the patient interface, may be at or above the level of the upper-most rim portion of the one or more oral openings.

[0176] At least part of the second chamber surface of the first resilient region at a vertical midplane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be below the level of the upper-most rim portion of the one or more oral openings and may be above the opening in the first housing. The forward panel and the rearward panel may extend laterally to a level that is between the lower-most rim portion of the one or more oral openings and a level halfway between the upper-most rim portion and the lower-most rim portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

[0177] The forward panel and the rearward panel may extend laterally to a level that is between the level of the upper-most portion of the one or more oral openings and a level half-way between the upper-most portion and lower-most portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

[0178] A proximal side of the second resilient region projecting into the first chamber may include a recess as part of the first opening of a flow director.

[0179] A distal side of the second resilient region projecting into the first chamber may include a recess as part of the first opening of a flow director.

[0180] The first housing and / or second housing may comprise the same material as the seal member.

[0181] According to a fourth aspect, there is provided a non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :

[0182] • an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and

[0183] • a dividing wall that separates the first chamber from the second chamber, wherein a volume ratio of the second chamber to the first chamber is in the range of 0.05: 1 to 0.7: 1.

[0184] The volume ratio of the second chamber to the first chamber may be greater than 0.1 : 1, greater than 0.15: 1, greater than 0.2: 1, greater than 0.25: 1, or greater than 0.3: 1. The volume ratio of the second chamber to the first chamber may be less than 0.65: 1, less than 0.6: 1, less than 0.55: 1, less than 0.5: 1, less than 0.45: 1, less than 0.4: 1, or less than 0.35: 1.

[0185] The volume of the first chamber may be in the range of 90 to 160 cm3.

[0186] The volume of the first chamber may be greater than 95 cm3, greater than 100 cm3, greater than 105 cm3, greater than 110 cm3, greater than 115 cm3or about 120 cm3.

[0187] The volume of the first chamber may be less than 155 cm3, less than 150 cm3, less than 145 cm3, less than 140 cm3, less than 135 cm3, less than 130 cm3, or less than 125 cm3.

[0188] The dividing wall may include a first resilient region that is linked to a distal portion of the outer wall, a second resilient region that is linked to a proximal portion of the outer wall and a deformation panel connecting between the first and second resilient regions.

[0189] The patient interface may include one or more flow directors which enable gas to flow into the second chamber from the first chamber and which flow directors are configured to direct the gas flow towards the one or more nare openings.

[0190] The volume of the first chamber may include the volume of the gas flow passages through the one or more flow directors.

[0191] The outer wall may include a sleeve which is configured to connect with a frame or a respiratory gas conduit and the volume of the first chamber excludes the volume defined by the sleeve.

[0192] The area of the one or more nare openings may be in the range of 130 to 340 mm2.

[0193] The area of the one or more nare openings may be in the range of 140 to 330 mm2.

[0194] The area of the one or more nare openings may be in the range of 150 to 320 mm2.

[0195] The one or more flow directors may be located in a central region of the dividing wall such that each flow director is spaced from a perimeter of the dividing wall. The one or more flow directors may extend into the first chamber or into the second chamber or into both the first and the second chambers.

[0196] The one or more flow directors may extend toward the one or more nare openings.

[0197] The flow directors may define a gas flow path from the first chamber to the second chamber and the flow directors surround the gas flow path.

[0198] The one or more flow directors may have a sealed join with the dividing wall.

[0199] Each of the one or more flow directors may have a second opening in the second chamber recessed from the one or more nare openings.

[0200] Each of the one or more flow directors may have an second opening within the second chamber and the second opening is spaced from the one or more nare openings.

[0201] The second opening may be defined by a rim.

[0202] The rim may be contoured so that at least a portion of the rim has a substantially consistent spacing from the one or more nare openings.

[0203] The portion of the rim that may be substantially consistently spaced from the one or more nare openings may be adjacent to the outer wall between the at least one or more nare openings and the at least one or more oral openings.

[0204] The rim of each second opening may extend further from the dividing wall at a laterally outer side of the flow director than the rim extends from the dividing wall at a laterally inner side of the flow director.

[0205] The rim of each second opening may be recessed further from the nare opening at a laterally inner side of the flow director than the rim is recessed at the laterally outer side of the flow director.

[0206] The rim of each second opening may be furthest recessed from the nare opening at a point that is between the laterally inner side of the flow director and the laterally outer side of the flow director. At least a portion of the rim of the second opening may be concentric with at least a portion of the rim of the nare opening.

[0207] The patient interface may include at least two flow directors that are spaced apart by a gap through which exhaled respiratory gas from the nares can flow into the second chamber.

[0208] The rim of each flow director may be spaced from the second resilient region less on the same side as the gap than the rim is spaced from the second resilient region on the side remote from the gap.

[0209] The flow directors may be configured with the lateral outer side of the rims adjacent to a lateral rim of the nare opening having regard to a direction of gas flow from the flow director.

[0210] The flow directors may be configured with the lateral outer side of the rim aligned with a lateral rim of the nare opening having regard to a direction of gas flow from the flow director.

[0211] Alternatively, each of the one or more flow directors may have an second opening flush with the one or more nare openings.

[0212] The one or more flow directors may be spaced from the outer wall.

[0213] The one or more flow directors may be linked to the outer wall.

[0214] The flow directors may be spaced apart by a spacing element which maintains a spacing between the flow directors.

[0215] Each flow director may have an second opening defined by a second opening rim and wherein the second opening rims are spaced from the lip superior wall portion.

[0216] The second opening rims may be recessed from the lip superior wall portion.

[0217] Each flow director may comprise a body defining a gas flow passage which extends between the second opening in the second chamber and an inlet which opens into the first chamber and wherein the body is spaced from the lip superior wall portion. The spacing element may be disposed between the flow directors.

[0218] The spacing element may be linked to the dividing wall.

[0219] The spacing element may link the flow directors to each other.

[0220] The spacing element may comprise a rib or web.

[0221] The spacing element may be spaced from the outer wall of the patient interface.

[0222] The spacing element may include a concave curved surface extending between the flow directors.

[0223] Each flow director may define an independent gas flow passage.

[0224] The body of one or more of the flow directors may be linked to the outer wall so that the gas flow passage is defined in part by the body and in part by the outer wall.

[0225] The one or more flow directors may be linked to the outer wall at or adjacent to the one or more nare openings.

[0226] The one or more flow directors may be linked to the outer wall laterally outwardly of the one or more nare openings.

[0227] The one or more flow directors may be linked to the outer wall distally of the one or more nare openings.

[0228] The one or more flow directors may be linked to the outer wall in the first chamber.

[0229] The one or more flow directors may be linked to the outer wall in the first chamber and in the second chamber.

[0230] The body of one or more of the flow directors may be linked to the outer wall between the at least one or more nare openings and the at least one or more oral openings.

[0231] The body of one or more of the flow directors may be linked to the outer wall on a side of the one or nare openings that is opposite to the wall portion. The body of one or more of the flow directors may be linked to the outer wall at or adjacent to the one or more nare openings.

[0232] The patient interface may include at least two flow directors that are spaced apart and part of each of the flow director bodies joins with the outer wall on a laterally outer side of a lateral rim of the one or more nare openings and another part of each of the flow director bodies may join with the outer wall laterally inwardly of the lateral rim of the one or more nare openings.

[0233] Each body may have a lateral wall and a medial wall both of which extend from spaced apart locations at the wall portion and which meet each other away from the wall portion.

[0234] The lateral wall and the medial wall may extend from the dividing wall to meet with the outer wall.

[0235] The lateral wall may join with the outer wall on a laterally outer side of the lateral rim of the one or more nare openings so that the rim of the at least one or more nare openings forms part of the rim of the flow director.

[0236] The medial wall may join with the outer wall on a laterally inward side of the lateral rim of the one or more nare openings so that part of the medial wall forms part of the rim of the flow director.

[0237] The rim of the second opening formed by the medial wall may be closer to the dividing wall than the rim of the second opening formed by the lateral rim of the one or more nare openings.

[0238] The body may be linked to the outer wall by a linking element.

[0239] The second opening of each flow director may be configured to direct respiratory gas laterally inwardly.

[0240] The deformation panel may accommodate at least some deformation force created by patient contact with the lip superior wall portion in preference to deformation of the flow directors.

[0241] The flow directors may be spaced from the deformation panel. The deformation panel may decouple one portion of the dividing wall from another portion of the dividing wall such that a force applied to one portion is greater than the force experienced by the decoupled portion.

[0242] The deformation panel may decouple one portion of the dividing wall from another portion of the dividing wall such that the two portions can move relative to each other.

[0243] The two portions of the dividing wall may be shaped to resist deformation.

[0244] The outer wall or the dividing wall may include resilient regions that translate deformation forces into the deformation panel such that deformation of the dividing wall is substantially confined to the deformation panel.

[0245] The deformation panel may be interposed between the flow directors and a resilient region.

[0246] The deformation panel may be disposed between the first resilient region and the flow directors.

[0247] The deformation panel may have a thickness that is less than the thickness of the first resilient region.

[0248] The deformation panel may comprise a first wall projecting from the first resilient region and a second wall connecting the first wall with a region of the dividing wall that includes the one or more flow directors.

[0249] The first and second walls may meet along a linking line.

[0250] The first and second walls may be adapted to deform in a predetermined sequence.

[0251] The predetermined sequence may include the first wall being folded towards the first resilient region.

[0252] The predetermined sequence may include the second wall buckling to accommodate a reduction in spacing between the first resilient region and the region of the dividing wall that includes the one or more flow directors. The second wall may be configured to induce buckling when the distance between the region of the dividing wall that includes the one or more flow directors and the linking line is less than the length of the second wall in the proximal-distal direction.

[0253] The second wall may have a curved profile from the linking line to the region of the dividing wall that includes the one or more flow directors to induce buckling of the second wall.

[0254] The second wall may increase in wall thickness from the first wall to the second resilient region to cause initial folding of the first wall during deformation and subsequent buckling in the second wall.

[0255] The deformation panel may have a wall thickness that is selected to induce deformation of the deformation panel in preference to the first and second resilient regions.

[0256] The first resilient region may have a thickness that is at least three times the thickness of the first wall.

[0257] The second wall may have a cross-section from the first wall to the region of the dividing wall that includes the one or more flow directors to induce a rolling movement in the second wall to accommodate deformation in the deformation region.

[0258] The second wall may increase in thickness from the first wall to the flow director region to cause initial folding of the first wall during deformation and subsequent rolling in the second wall starting from an intersection between the second wall and the first wall.

[0259] A notional line extending from an intersection line between the first resilient region and the first wall may converge at a pivot point with another notional line extending along the linking line between the first wall and the second wall.

[0260] The first resilient region may comprise a first thickened region of the dividing wall.

[0261] The first thickened region may comprise a resilient lip adjoining the deformation panel.

[0262] The deformation of the deformation panel may involve a reduction in the spacing between the first resilient region and the region of the dividing wall that includes the one or more flow directors. The patient interface may include one or more resilient regions that are configured to bear at least some deformation forces applied to the lip superior wall portion such that the one or more flow directors bear less of the deformation forces than the resilient regions.

[0263] The one or more resilient regions may be configured to reduce the extent to which the flow directors deform due to deformation forces applied to the lip superior wall portion.

[0264] The one or more resilient regions may increase the resistance to deformation of a region of the dividing wall that includes the one or more flow directors.

[0265] The dividing wall may include one or more resilient regions between the lip superior wall portion and the deformation panel.

[0266] The one or more resilient regions may be in the region of the dividing wall that includes the one or more flow directors.

[0267] One or more of the resilient regions may include ribs associated with the dividing wall.

[0268] One or more of the resilient regions may be integrally formed with the dividing wall.

[0269] One or more of the resilient regions may comprise portions of the dividing wall that have a wall thickness that is greater than the wall thickness of other portions of the dividing wall.

[0270] One or more of the resilient regions may be configured to direct deformation forces that are applied to the lip superior wall portion into the deformation panel.

[0271] One or more of the resilient regions may extend from or adjacent to the lip superior wall portion and extend within the region of the dividing wall that includes the one or more flow directors to direct deformation forces into the deformation panel.

[0272] One or more of the resilient regions may be wider at an end at or adjacent to the lip superior wall portion than at an end remote from the lip superior wall portion.

[0273] One or more of the resilient regions may comprise a deformation translation rib formed on an underside of the dividing wall. One or more of the resilient regions may be configured to cause the flow directors to track deformation of the lip superior wall portion.

[0274] One or more of the resilient regions may be configured on the underside and topside of the dividing wall to overlap at least in part.

[0275] One or more of the resilient regions may be located where the flow directors join with the dividing wall.

[0276] One or more of the resilient regions which are located where the flow directors join with the dividing wall may be linked to the lip superior wall portion.

[0277] One or more of the resilient regions which are located where the flow directors join with the dividing wall may be linked to the lip superior wall portion by one or more other resilient regions

[0278] One or more of the resilient regions which are located where the flow directors join with the dividing wall may reinforce the region of the dividing wall that includes the one or more flow directors so that at least some of the deformation force applied to the lip superior wall portion is transferred to the deformation panel.

[0279] One or more of the resilient regions which are located where the flow directors join with the dividing wall may be disposed on the topside or the underside of the dividing wall, having regard to a generally upright orientation of the patient interface.

[0280] The one or more resilient regions may be linked to the lip superior wall portion by one or more other resilient regions disposed on the underside or the topside, having regard to a generally upright orientation of the patient interface.

[0281] One or more of the resilient regions may overlap with the spacing element so that the flow directors track movement of the one or more deformation resistant sections which overlap with the spacing element.

[0282] The resilient regions which overlap with the spacing element may extend substantially orthogonally with respect to each other.

[0283] One or more of the resilient regions may be configured on the underside and topside of the dividing wall, having regard to a generally upright orientation of the patient interface, to transform deformation forces applied to the lip superior wall portion into deformation of the deformation panel.

[0284] One resilient region may be configured to overlap at least in part with another of the one or more resilient regions.

[0285] The one or more flow directors may be configured to accelerate respiratory gas from the first opening of the one or more flow directors to their second opening.

[0286] The second opening of the one or more flow directors may have a combined area that is less than the area of the one or more nare openings.

[0287] The second opening of the one or more flow directors may be aligned with laterally outer sides of the one or more nare openings.

[0288] Each flow director may comprise a body which has a cross-sectional area that reduces in the direction from first opening to the second opening.

[0289] The body may include an lower body portion and a upper body portion and wherein the upper body portion has a cross-sectional area that is less than the cross-sectional profile of the lower body portion.

[0290] The lower body portion may have a conical profile in cross-section in the proximal-distal direction through an axis of the gas flow passage through the flow director.

[0291] The upper body portion may have a conical profile in cross-section in the proximal-distal direction through an axis of the gas flow passage through the flow director.

[0292] The upper body portion may have a circular, elliptical or oval-shaped profile in crosssection generally parallel to the dividing wall where the flow director is located.

[0293] The body may have a conical profile or a stepped profile in cross-section in the proximal-distal direction through an axis of the gas flow passage through the flow director.

[0294] The body may have a tapering profile in cross-section in the proximal-distal direction through an axis of the gas flow passage through the flow director. The patient interface may have an inlet to the first chamber for respiratory gas.

[0295] The patient interface may have an exhaust outlet that is configured to exhaust respiratory gas from the patient interface.

[0296] The exhaust outlet may be configured to exhaust respiratory gas from the second chamber.

[0297] The exhaust outlet may be configured to exhaust respiratory gas from the first chamber and the second chamber.

[0298] The exhaust outlet may comprise a first exhaust outlet and a second exhaust outlet.

[0299] The seal member may include a nare-sealing portion that includes the one or more nare openings and the seal member further includes a mouth-sealing portion that includes the one or more oral openings.

[0300] The seal member may be a resilient material and may be connected to the housing to form a unitary structure.

[0301] The seal member may be a resilient material and may be mechanically locked to the housing to form a unitary structure.

[0302] The seal member may be over moulded onto the housing to mechanically lock and / or chemically bond with the housing.

[0303] The patient interface may further include a mask frame.

[0304] The mask frame may be removably connectable to the housing.

[0305] The mask frame may be removably connectable by co-operable snap-fit formations on the housing and on the mask frame.

[0306] The mask frame may be permanently connectable to the housing by co-operable formations on the housing and the mask frame.

[0307] The mask frame and the housing may be integrally formed. The mask frame or the housing may further comprise headgear connectors for connecting a headgear to the patient interface.

[0308] The patient interface may further include a conduit connector.

[0309] The patient interface may include a rotator cuff that rotatably links the conduit connector to the mask frame to form a flow path for respiratory gas from a conduit to the first chamber.

[0310] The dividing wall is configured to reduce movement of the flow directors toward each other.

[0311] The dividing wall is configured to reduce collapse of the flow directors.

[0312] The dividing wall is configured to reduce buckling of the flow directors.

[0313] The dividing wall is configured to reduce collapse or buckling of the flow directors inwardly toward each other.

[0314] The dividing wall is configured to reduce laterally inward travel of the forward and rearward panels upon deformation of the deformation region.

[0315] The flow directors are disposed between the lip superior wall portion of the outer wall and the deformation panel, and the lateral side portions are disposed laterally outwardly of the flow directors.

[0316] The first opening of the one or more flow directors may have a shape with a major axis which is longer than an orthogonal minor axis.

[0317] The major axis may be within a plane of the dividing wall and is oriented at least 45° from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to a generally upright orientation of the patient interface.

[0318] The major axes of the respective first openings may intersect at a point that is on a proximal side of a notional straight line that passes through the centres of the first openings. The major axes of the respective first openings may intersect at a point that is proximal of the lip superior wall portion of the outer wall.

[0319] An angle between the major axes where they intersect may be less than 180°.

[0320] The angle between the major axes where they intersect may be in the range of 45° to less than 180°.

[0321] The angle between the major axes where they intersect may be in the range of 90° to 150°.

[0322] The angle between the major axes where they intersect may be in the range of 110° to 150°.

[0323] The major axes of the respective first openings may intersect at a point that is on a distal side of a notional straight line that passes through the centres of the first openings.

[0324] The first openings may be disposed between the deformation panel and the lip superior wall portion of the outer wall and extend a distance that is less than the distance between the lip superior wall portion of the outer wall portion and the deformation panel.

[0325] The first openings may be disposed between the deformation panel and the lip superior wall portion of the outer wall between the one or more nare openings and the one or more oral openings and extend a distance that is less than the distance between the lip superior wall portion of the outer wall portion and the deformation panel.

[0326] The flow director forming each first opening may be spaced from the deformation panel.

[0327] Each first opening of the one or more flow directors may have an elliptical shape.

[0328] The orientation of the major and minor axes may be retained throughout the flow director.

[0329] The dimension of the major axis or the minor axis or both major and minor axes at the second opening may be different from the dimension of the major axis or the minor axis or both major and minor axes at the first opening. The dimension of the major axis or the minor axis or both major and minor axes at the second opening may be less than the dimension of the major axis or the minor axis or both major and minor axes at the first opening.

[0330] The dimension of the major axis or the minor axis or both major and minor axes may vary through the flow director.

[0331] The dimension of the major axis or the minor axis or both major and minor axes may decrease from the first opening to the second opening.

[0332] The dimension of the major axis or the minor axis or both major and minor axes vary to define a constriction.

[0333] The second opening of each flow director may be spaced from the outer wall to enable gas flow between the first chamber and the second chamber, and wherein the second openings are positioned such that a gas stream flowing from the first chamber into the second chamber through the flow directors would impinge at least partly on the outer wall when the patient interface is not fitted to a patient.

[0334] The area, shape or shape and area of the nare openings may change when the patient interface is fitted to a patient.

[0335] The area, shape or shape and area of the one or more nare openings may change when the patient interface is fitted to a patient such that a gas stream passing through the flow director would be directed through the one or more nare openings without impinging upon the outer wall.

[0336] The flow directors and the outer wall may be arranged such that the outer wall extends over part of each second opening when the patient interface is not fitted.

[0337] The outer wall may extend over part of the second openings when viewed from vertically above a mid-point between the second openings, having regard to an upright orientation of the patient interface, when the patient interface is not fitted to a patient.

[0338] The part of the second opening over which the outer wall extends may be a laterally outer part of the second opening. At least part of each second opening may be outside a notional columnar volume having the profile of and extending upwardly through the one or more nare openings, having regard to an upright orientation of the patient interface, when the patient interface is not fitted to a patient.

[0339] At least part of each second opening may be obscured by the outer wall when the patient interface is viewed from vertically above a mid-point between the second openings having regard to an upright orientation of the patient interface when the patient interface is not fitted to a patient.

[0340] When the patient interface is fitted to a patient, laterally outer edges of the one or more nare openings may be disposed laterally outwardly of the second openings of the respective flow directors.

[0341] The outer wall may be configured to enable the one or more nare openings to extend laterally outwardly.

[0342] The outer wall may be configured to extend laterally outwardly so that the outer wall does not extend over part of each second opening when the patient interface is viewed from vertically above a mid-point between the second openings having regard to an upright orientation of the patient interface when the patient interface is fitted to a patient.

[0343] The lip superior wall portion of the outer wall may be configured to enable the outer wall which extends over the second openings of the flow directors to shift laterally outwardly so that the outer wall no longer extends over the second openings when the patient interface is fitted to a patient.

[0344] The outer wall may include a nare-sealing portion which is curved to receive the underside of a patient's nose when the patient interface is fitted to a patient.

[0345] A radius of curvature of the curved nare-sealing portion may reduce when the patient interface is fitted.

[0346] The outer wall may include a valley-shape configured to receive the underside of a patient's nose and a base of the valley-shape, which includes the one or more nare opening, adopts a flatter valley-shape when the patient interface is fitted to a patient. The dividing wall may include the flow directors.

[0347] The flow directors may enable gas flow between the first chamber and the second chamber.

[0348] Each flow director may include a base which defines a first opening from the first chamber, a body extending from the base, a rim remote from the base and which rim defines a second opening which opens into the second chamber and a gas flow passage extending from the first opening in the base to the second opening.

[0349] The body may include a reinforced segment that is configured to resist deformation of the shape of the second opening under a deformation force.

[0350] The reinforced segment may extend wholly or partly around the body.

[0351] The reinforced segment may have a wall thickness that is greater than the wall thickness of other parts of the body.

[0352] The reinforced segment may include a rib.

[0353] The body may be formed of a first material and the reinforced segment may be formed from a second material which is different from the first material.

[0354] The second material may be less compliant than the first material.

[0355] The reinforced segment may extend around at least part of a distal side of the body.

[0356] The reinforced segment may be located on one side of a major axis of the flow director profile generally parallel to the dividing wall.

[0357] The reinforced segment may be disposed around the body at a set spacing from the rim.

[0358] The reinforced segment may be disposed around the body at a set spacing from the base.

[0359] The reinforced segment may be disposed around the body at a varying spacing from the rim. The reinforcing segment may be disposed adjacent to the rim.

[0360] The reinforcing segment may be disposed on an exterior of the body.

[0361] The body may include a lower body portion and an upper body portion.

[0362] The reinforced segment may extend wholly or partly around the lower body portion.

[0363] The reinforced segment may extend wholly or partly around the upper body portion.

[0364] The reinforced segment may extend from the lower body portion and at least partly around the upper body portion.

[0365] The upper body portion may have a wall thickness that is less than the wall thickness of the lower body portion.

[0366] The base of each flow director may be elongate in the lateral direction away from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

[0367] The base of the or each flow director defines a footprint on the second chamber surface of the rearward panel.

[0368] The gas flow passage may be closer to the laterally inward side of the footprint of the base than the laterally outward side of the footprint of the base.

[0369] The laterally-outer side of the footprint of the base may extend laterally outwardly further from the gas flow passage than a laterally-inward side of the base extends laterally inwardly from the gas flow passage.

[0370] The laterally-outer side of the footprint of the base may extend laterally outwardly from the gas flow passage at least two times, at least three times, at least four times or at least five times further than the laterally-inward side of the footprint of the base extends laterally inwardly from the gas flow passage.

[0371] The footprint may extend laterally beyond a corresponding lateral edge of the one or more nare openings. The gas flow passage may have a longitudinal axis between the first opening and the second opening and which axis is off-set laterally inwardly from a centreline in the proximal-distal direction through the base, so that the gas flow passage is closer to the laterally inward side of the base than the laterally outward side of the base.

[0372] The base may include a wall thickness that is larger than the wall thickness of the dividing wall adjacent to the base.

[0373] The base may include a thickened pad which extends laterally outwardly of the body.

[0374] The thickened pad may decrease in wall thickness away from the body.

[0375] The thickened pad may have a wedge-shaped profile in the laterally outward direction.

[0376] The base may wrap, at least in part, around the body.

[0377] The base may include a laterally-outer side that is configured to resist displacement of the second openings toward each other.

[0378] The laterally-outer side of the base may be configured as a reinforced link between the dividing wall and the body so that flexing of the dividing wall that causes displacement and changes in orientation of the body is resisted.

[0379] The laterally outer side of the base may taper from the dividing wall to the body.

[0380] The taper of the laterally-outer side of the base may have a fillet shape.

[0381] The laterally-outer side of the base may include a radial wall thickness, having regard to the longitudinal axis of the gas flow passage between the first and second openings that is greater than the radial wall thickness at any point on the remainder of the body.

[0382] The base of each flow director may include a block which includes the gas flow passage and which has a thickness that resists deformation of the body.

[0383] The base may be configured to resist displacement and changes in orientation of the body by transferring deformation forces imparted on the outer wall to the deformation panel. The bases of the flow directors may be linked together to form a common block from which separate bodies extend.

[0384] The common block may have a footprint which extends laterally beyond corresponding lateral edges of the one or more nare openings.

[0385] The common block may have inclined sides which extend from the lateral side portions of the dividing wall to the bodies.

[0386] A region of the common block which is bound by the inclined sides may be tapered downwardly in the distal direction.

[0387] The region may be tapered to be substantially parallel to the one or more nare openings.

[0388] The inclined side of the common block may include a fillet-shape.

[0389] The fillet-shape may be continuous about the lateral side of the common block.

[0390] The fillet-shape may be continuous about proximal and distal sides of the common block.

[0391] The fillet shape may be continuous about proximal and distal sides of the common block, including the spacing portion.

[0392] The wall thickness of the flow director may decrease from the base towards the rim.

[0393] The body may include a transition that is intermediate the base and the rim.

[0394] The transition may delineate the upper body portion from the lower body portion.

[0395] The upper body portion may include a wall thickness that is less than the wall thickness of the lower body portion.

[0396] The wall thickness of the lower body portion may be constant and the wall thickness of the upper body portion decreases from the transition to the rim. The wall thickness of the body may vary from the transition to the rim.

[0397] The wall thickness of the body may decrease from the transition to the rim.

[0398] The decrease in wall thickness of the body from the transition to the rim may be constant.

[0399] The decrease in wall thickness of the body from the transition to the rim may be not constant.

[0400] The transition may be inclined relative to the dividing wall.

[0401] The transition may be inclined so that a distal side of the lower body portion extends further from the base than a proximal side of the lower body portion extends from the base.

[0402] A plane defined by the transition may be generally parallel to the one or more nare openings, or the outer wall above the flow director, or the one or more nare openings and the outer wall above the flow director, having regard to an upright orientation of the patient interface.

[0403] The rim of the upper body portion may be generally parallel to the one or more nare openings, or the outer wall above the flow director, or the one or more nare openings and the outer wall above the flow director, having regard to an upright orientation of the patient interface.

[0404] The lower body portion may have a wall thickness selected to resist deformation more than the deformation region resists deformation so that the deformation region preferentially deforms in response to a deformation force applied to the proximal side of the seal member.

[0405] An external surface of a distal side of the flow director may have a curved profile in the direction of the longitudinal axis of the flow director between the first and second openings.

[0406] The decrease in wall thickness of the flow director from the transition to the rim may be due to the external surface of the flow director tapering inwardly toward an internal surface of the flow director. The transition may include, at least in part, a step which is intermediate the base and the rim.

[0407] The body below the step may have a first wall thickness and the body above the step has a second wall thickness and wherein the second wall thickness is less than the first wall thickness.

[0408] The step may extend around at least the distal side of the flow director.

[0409] The step may extend around the distal and laterally outer sides of the flow director.

[0410] The step may extend substantially all the way around the flow director.

[0411] The step may extend all the way around the flow director.

[0412] The step may include an inclined surface which connects the lower body portion to the upper body portion.

[0413] The step may be formed on the exterior of the flow director.

[0414] Having regard to the longitudinal axis of the flow director between the first and second openings, the radial wall thickness of the lower body portion may vary about the flow director.

[0415] Having regard to the longitudinal axis of the flow director between the first and second openings, the radial wall thickness of the lower body portion may vary with the spacing of the rim from the base.

[0416] Having regard to the longitudinal axis of the flow director between the first and second openings, the radial wall thickness of the lower body portion may be larger where the rim is spaced further from the base than where the rim is spaced less from the base.

[0417] Having regard to the longitudinal axis of the flow director between the first and second openings, the radial wall thickness of the lower body portion may be least where the spacing between the rim and the base is the least and increases with increasing spacing between the rim and the base. The radial wall thickness of the lower body portion may be constant around the flow director.

[0418] The radial wall thickness of the upper body portion may be constant around the flow director.

[0419] The dividing wall may include a spacing rib disposed between the bodies of the flow directors.

[0420] The spacing rib may join with the bodies at a position spaced from the rim.

[0421] The spacing rib may join with the base and bodies of the flow directors up to a position spaced from the rim.

[0422] The spacing rib joins with the base and the lower body portions only of the flow directors.

[0423] The flow directors may include a step between the lower body portion and the upper body portion and the spacing rib joins with the step.

[0424] The spacing rib may have a flattened upper surface which joins with the step.

[0425] The spacing rib may join with the base and the lower body portions and the steps of the flow directors only.

[0426] The spacing rib may include a fillet-shaped transition joint with the flow directors.

[0427] The spacing rib may be disposed in a plane which intersects the longitudinal axes of the flow directors.

[0428] The spacing rib may have a wall thickness in the distal-proximal direction that is 5 to 20 % of the dimension of the flow director in the distal-proximal direction.

[0429] The spacing rib may have a wall thickness in the distal-proximal direction that is 20 to 40 % of the dimension of the flow director in the distal-proximal direction.

[0430] The spacing rib may have a wall thickness in the distal-proximal direction that is 40 to 60 % of the dimension of the flow director in the distal-proximal direction. The spacing rib may overlap with a reinforcement section of the dividing wall which is arranged to transfer deformation forces applied to the proximal side of the outer wall to the deformation panel.

[0431] The dividing wall may include a respective brace member disposed between each flow director and the outer wall and which brace member maintains a spacing between the outer wall and the respective flow director.

[0432] Each brace member may join with the outer wall at the lip superior wall portion between the one or more nare openings and the one or more oral openings.

[0433] Each brace member may join with the lip superior wall portion and with the lower body portion only.

[0434] Each brace member may join with the lip superior wall portion and with the lower body portion and the step portion only.

[0435] Each brace member may join with the lip superior wall portion and with the common block.

[0436] Each brace member may join with the lip superior wall portion and with a respective block of the flow directors.

[0437] Each brace member may have a lateral width which is 20 to 70 % of the lateral width of the flow director.

[0438] The brace member may have a polygonal cross-sectional profile.

[0439] The brace member may have a trapezoidal cross-sectional profile.

[0440] The brace member may have a semi-circular cross-sectional profile.

[0441] The brace member may have a circle-segment cross-sectional profile.

[0442] The brace member may have a curved cross-sectional profile.

[0443] The patient interface is configured to deliver pressurised respiratory gas to a patient. According to a fifth aspect, there is provided a non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface comprising :

[0444] • an outer wall defining an interior volume which comprises a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and

[0445] • a dividing wall that separates the first chamber from the second chamber,

[0446] • an inlet configured to convey respiratory gas to the first chamber, wherein the outer wall comprises a seal member and a housing connected to the seal member to form part of the outer wall.

[0447] The housing may form part of the outer wall associated with the second chamber.

[0448] The housing may be integrally formed with the seal member.

[0449] The housing may be over-moulded to the seal member.

[0450] The housing may be removably joined to the seal member.

[0451] The housing may comprise a groove into which the seal member may be mounted.

[0452] The seal member may be pulled over the housing to be mounted in the groove.

[0453] The seal member may be expanded over the housing to be mounted in the groove.

[0454] The housing may be removably joined to the seal member via a press fit connection.

[0455] The seal member may be removably connected to two components of the housing.

[0456] The seal member may be mounted between the two components of the housing.

[0457] The seal member may be clamped between the two components of the housing. The housing may be located above the inlet, having regard to a generally upright orientation of the patient interface.

[0458] The dividing wall may comprise a first resilient region that is linked to a distal side of the outer wall, a second resilient region that is linked to a proximal side of the outer wall and a deformation panel connecting between the first and second resilient regions.

[0459] The first resilient region may extend in a proximal direction from a distal portion of the outer wall.

[0460] The first resilient region may extend from a region above the inlet.

[0461] The first resilient region may extend from a region below the housing.

[0462] The first resilient region may extend from a region between the inlet and the housing.

[0463] The second resilient region may extend from a region below the second opening.

[0464] The second resilient region may extend from a region above the first opening.

[0465] The first resilient region and the deformation panel may meet at a level that is lower than the level where the second resilient region and the deformation panel meet.

[0466] The first resilient region and the deformation panel may meet at a level that is below a level where the second resilient region and the deformation panel meet at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to a generally upright orientation of the patient interface.

[0467] The first resilient region and the deformation panel may meet at a level that is below, having regard to a generally upright orientation of the patient interface, the level where the second resilient region and the deformation panel meet at each respective lateral location between laterally outer-most edges of the one or more nare openings.

[0468] The patient interface may comprise; a first distal opening in the first chamber which is defined by a first rim and; a second distal opening in the second chamber which is defined by a second rim, having regard to a generally upright orientation of the patient interface.

[0469] The housing may be co-operable with the second rim.

[0470] The housing and the second rim of the second distal opening may comprise co-operable seal-forming formations.

[0471] The housing may comprise an outlet panel and a fastening bracket which are co- operable to form a seal between the housing and the second distal opening.

[0472] The outlet panel and the fastening bracket may be co-operable to form a seal against the second rim.

[0473] The second rim may comprise a rim profile that complements a seal formation on the outlet panel and / or the fastening bracket.

[0474] The first resilient region may comprise a lateral profile that may follow the contour of the second rim portion between the lateral edges of the second distal opening.

[0475] The first resilient region may comprise a second chamber surface exposed to the second chamber and the second resilient region comprises a second chamber surface exposed to the second chamber.

[0476] At least part of the second chamber surface of the first resilient region at a vertical midplane through the patient interface, having regard to an upright orientation of the patient interface, may beat or above the level of the upper-most rim portion of the one or more oral openings.

[0477] The patient interface comprises a first housing associated with the first distal opening and a second housing associated with the second distal opening.

[0478] At least part of the second chamber surface of the first resilient region at a vertical midplane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, may be below the level of the upper-most rim portion of the one or more oral openings and is above the inlet. The dividing wall may comprise a forward panel, the forward panel comprises the first resilient region.

[0479] The dividing wall may comprise a rearward panel, the rearward panel comprises the second resilient region.

[0480] The forward panel may link to the distal side of the outer wall and is distal of the deformation panel.

[0481] The rearward panel may link to the proximal side of the outer wall and is proximal of the deformation panel.

[0482] The forward panel and the rearward panel may extend laterally to a level that is between the lower-most rim portion of the one or more oral openings and a level halfway between the upper-most rim portion and the lower-most rim portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

[0483] The forward panel and the rearward panel may extend laterally to a level that is between the level of the upper-most portion of the one or more oral openings and a level half-way between the upper-most portion and lower-most portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

[0484] An upper portion of the second housing above a notional laterally extending line between the laterally outer-most parts of the second housing may comprise a radius of curvature that is less than a radius of curvature of a nasal portion below the notional laterally extending line.

[0485] The patient interface may comprise a frame which is connectable to headgear.

[0486] The frame may comprise connecting formations that are connectable with headgear.

[0487] The frame may comprise two components.

[0488] The frame may comprise a frame body and a frame clip.

[0489] The frame body may comprise a connector sleeve. The frame clip may comprise a frame clip wall, the frame clip wall is shaped to fit internal contours of the outer wall.

[0490] The frame clip and the frame body are removably connectable to each other.

[0491] The frame clip may comprise key formations, the connector sleeve comprises receiving structures to receive the key formations such that the frame clip and the frame body are aligned in a predetermined orientation when removably attached to each other.

[0492] The frame clip may comprise key formations, the connector sleeve comprises receiving structures to receive the key formations when the frame clip is aligned with the internal contours of the outer wall.

[0493] The frame clip may comprise a frame clip protrusion co-operable with a first indent of the frame body.

[0494] The frame clip may form a one-way snap-fit connection with the first indent of the frame body.

[0495] A part of the seal member may be clamped between the frame body and the frame clip when the frame is attached to the seal member.

[0496] The frame may be removably attached to the seal member.

[0497] The first rim may be provided on the outer wall.

[0498] The first rim extends in a direction distal of the first distal opening.

[0499] The first rim may be mounted within a second indent of the frame body.

[0500] The first rim may be the thickest region of the seal member on the outer wall.

[0501] The first rim may be more rigid than the seal member. The frame may comprise an opening for coupling the frame to a respiratory gas conduit.

[0502] The frame may be removably attached to the seal member.

[0503] The frame may be permanently attached to the seal member.

[0504] The frame may be adhered to the seal member.

[0505] The seal member may be pulled over the frame and attached by compressive forces.

[0506] The frame may press-fit into the seal member.

[0507] The first distal opening may be provided on the outer wall for delivery of respiratory gas into the first chamber and the housing may comprise an outlet for exhausting gas from the second chamber.

[0508] The patient interface comprises one or more flow directors which enable gas to flow into the second chamber from the first chamber.

[0509] The dividing wall includes one or more flow directors configured to direct the gas flow towards the nare openings.

[0510] The flow directors may be spaced apart by a spacing element which maintains a spacing between the flow directors.

[0511] The flow directors may extend into the first chamber.

[0512] The flow directors may extend into the second chamber.

[0513] The flow directors may have a sealed joint with the dividing wall.

[0514] The or each flow director comprises a channel through the dividing wall.

[0515] The or each flow director comprises an aperture through the dividing wall.

[0516] The or each flow director comprises an aperture through the second resilient region. The second opening of the or each flow director is flush with the second chamber surface of the second resilient region.

[0517] Throughout the above disclosure, the following description and the claims, the terms "proximal" and "distal" and their grammatical variants are references to the respective proximal direction and the distal direction. Proximal direction references indicate a direction that is toward a patient as if the patient interface were fitted to a patient. Distal references indicate a direction that is away from the patient as if the patient interface were fitted to a patient. These directions are shown in Figures 1 and 4. The same directionality applies to all of the drawings and all of the embodiments disclosed in this specification. Use of the terms "proximal" and "distal" is not to be taken as indicating a state when the patient interface is fitted to a patient, unless the context indicates otherwise.

[0518] Throughout the above disclosure, the following description and the claims, references to "up", "down", "upward", downward", "upwardly", "downwardly", "vertical" and "vertically" are references to directions having regard to an upright orientation of the patient interface. The "up" and "down" directions are shown in Figure 1 and are orthogonal to the proximal and distal directions and orthogonal to the lateral direction.

[0519] The flow directors described above may be combined with any of the patient interface configurations disclosed above in respect of the first, second, third, fourth and fifth aspects. The same applies to all other features described in the following description, namely, any one or more of the alternative configurations described below and associated with one of the aspects disclosed above may be combined with any of the other alternative configurations described below in respect of the same aspect or a different aspect disclosed above.

[0520] Throughout the above disclosure, the following description and the claims, the term "chamber" is taken to mean a structure of the patient interface that at least partly defines a volume and which structure has one or more respiratory gas inlets and one or more respiratory gas outlets.

[0521] Throughout the above disclosure, the following description and the claims, the term "level" is taken to mean a plane that is orthogonal to the up-down direction and that is at a position designated by the context in which the term appears. For example, lines along D-D and H-H in Figure 7 represent two different levels. Although various features are disclosed above in relation to one or more aspects, it will be appreciated that one or more features of any aspect may be combined with other aspects to arrive at additional embodiments. It follows that disclosure of features in the preceding statements should not be interpreted as meaning that the features are limited in application to the aspects in respect of which they are disclosed. For example, the features disclosed in respect of the first aspect regarding the dividing wall and the flow directors are equally applicable to each of the remaining aspects.

[0522] Ordinal references (e.g. first, second, third, fourth, fifth) to aspects disclosed above only serve to differentiate aspects from one another. The ordinal references are not to be interpreted as the order of importance of the aspects.

[0523] BRIEF DESCRIPTION OF THE DRAWINGS

[0524] The aspects of the patient interface disclosed above are described in detail below by reference to embodiments, which serve as examples only, and with reference to the accompanying drawings, in which:

[0525] Figure 1 is an oblique view of a patient interface according to one embodiment;

[0526] Figure 2 is an exploded oblique view of the patient interface of Figure 1;

[0527] Figure 3 is a rear view of the patient interface of Figure 1;

[0528] Figure 4 is a side cross-section view of the patient interface along the line A-A in Figure 1;

[0529] Figure 5 is a cross-section of the gas conduit connector along the line B-B in Figure 4;

[0530] Figure 6 is a front plan view of a housing which forms part of the patient interface of Figure 1;

[0531] Figure 7 is front plan view of a seal member of the cushion module of the patient interface in Figure 1;

[0532] Figure 8 is a side plan view of the seal member in Figure 7;

[0533] Figure 9 is a cross-section side view of the seal member along the line A-A in Figure 7; Figure 10 is a magnified view of the region marked B in the cross-section side view of Figure 9;

[0534] Figure 11 is a magnified cross-section side view of the seal member along the line C-C in Figure 7;

[0535] Figure 12 is a cross-section top view of the seal member along the line D-D in Figure 7;

[0536] Figure 13 is a cross-section front view of the seal member along the line E-E in Figure 8;

[0537] Figure 14 is a cross-section front view of the seal member along the line F-F in Figure 8;

[0538] Figure 15 is a cross-section oblique view of the same cross-section view of the seal member in Figure 14;

[0539] Figure 16 is a magnified cross-section view of the seal member along the line G-G in Figure 8;

[0540] Figure 17 is a cross-section top view of the seal member along the line D-D in Figure 7 with an alternative dividing wall;

[0541] Figure 18 is a magnified cross-section side view of the seal member along the line A-A in Figure 7 with the alternative dividing wall of Figure 17;

[0542] Figure 19 is a cross-section side view of the seal member along the line D-D in Figure 7 with a further alternative dividing wall;

[0543] Figure 20 is an oblique view of the cross-section along the line D-D in Figure 7 of the seal member with the alternative dividing wall of Figure 19;

[0544] Figure 21 is an oblique cross-section of the seal member along the line H-H in Figure 7 with the further alternative dividing wall of Figure 19;

[0545] Figure 22 is an oblique cross-section of the seal member along the line C-C in Figure 7 with the further alternative dividing wall of Figure 19; Figure 23 is a front plan view of an alternative cushion module for the patient interface in Figure 1;

[0546] Figure 24 is a side plan view of the alternative cushion module shown in Figure 31;

[0547] Figure 25 is a rear plan view of the alternative cushion module shown in Figure 31;

[0548] Figure 26 is an oblique cross-section view of the seal member only along the line N-N in Figure 23;

[0549] Figure 27 is a cross-section bottom view of the seal member only along the line P-P in Figure 23;

[0550] Figure 28 is a cross-section side view of the seal member only along the line Q-Q in Figure 23;

[0551] Figure 29 is a cross-section side view of the seal member only along the line R-R in Figure 23;

[0552] Figure 30 is a cross-section side view of the seal member only along the line S-S in Figure 23;

[0553] Figure 31 is a cross-section front view of the seal member only along the line T-T in Figure 24;

[0554] Figure 32 is a cross-section side view of the alternative cushion module along the line Q-Q in Figure 23;

[0555] Figure 33 is front plan view of an outlet panel of a first housing of the alternative cushion module in Figure 23;

[0556] Figure 34 is an oblique rear view of the outlet panel in Figure 33;

[0557] Figure 35 is front plan view of a connector panel of the first housing of the alternative cushion module in Figure 23;

[0558] Figure 36 is an oblique rear view of the connector panel in Figure 35; Figure 37 is a front plan view of a second housing of the alternative cushion module in Figure 23;

[0559] Figure 38 is an oblique rear view of the second housing in Figure 37; and

[0560] Figure 39 is a cross-section side view along the line Q-Q in Figure 23 of the second housing in Figure 37.

[0561] Figure 40 is a magnified view of the region marked D in the cross-section side view of Figure 32 showing connection of an outlet panel and a connector panel.

[0562] Figure 41 is a front view of a further alternative patient interface.

[0563] Figure 42 is an oblique view of the seal member of the further alternative patient interface shown in Figure 41.

[0564] Figure 43 is a front view of the cushion module shown in Figures 42.

[0565] Figure 44 is a cross-sectional side view of the cushion module shown along the line U-U in Figure 43.

[0566] Figure 45 is a cross-sectional side view along the line U-U in Figure 41 of the seal member and frame and without the conduit connector.

[0567] Figure 46 is an oblique front view of the frame of the patient interface in Figure 41.

[0568] Figure 47 is an exploded oblique rear view of the frame of the patient interface in Figure 41.

[0569] Figure 48 is a cross-sectional oblique view of the frame in Figure 46 along the line U-U in Figure 41.

[0570] Figure 49 is a cross-sectional side view of a frame clip shown in Figures 47 and 48 along the line U-U of Figure 41.

[0571] Figure 50 is a side view of the seal member and the housing of the patient interface shown in Figure 41. Figure 51 is a cross-sectional side view along the line U-U of Figure 41 of the cushion module and the housing in Figure 50.

[0572] Figure 52 is a magnified view of the region marked E in Figure 51.

[0573] Figure 53 is an oblique rear view of an outlet panel of the housing in Figures 41 and 52.

[0574] DESCRIPTION OF EMBODIMENTS

[0575] Embodiments will now be described in the following text which includes reference numerals that correspond to features illustrated in the accompanying figures. Where possible, the same reference numeral has been used to identify the same or substantially similar features in the different embodiments. To maintain clarity of the figures, however, all reference numerals are not included in each figure.

[0576] The aspects of the patient interface disclosed above will be described in detail below by reference to embodiments of a patient interface in the general form shown in Figures 1 to 4. The embodiments described below are variations on that general form. However, it will be appreciated that the scope of the aspects should not be limited by reference to that general form or to the specific embodiments described below and, instead, the aspects should be interpreted as relating to other forms of patient interface that also deliver pressurised respiratory gas to the patient, including patient interfaces that extend across the bridge of the nose, total-face masks and full-head helmets.

[0577] The term "respiratory gas" as used throughout this specification is taken to mean a gas used in human respiration. The term "inhaled respiratory gas" as used throughout this specification is taken to mean respiratory gas that is inhaled during the inhalation phase of the breathing cycle. The term includes within its scope ambient air or air that is conditioned for treating a patient, such as having elevated humidity or elevated oxygen levels or both compared to ambient air. The term "exhaled respiratory gas" as used throughout this specification is taken to mean respiratory gas that is exhaled from the lungs and airways of a patient. It, therefore, includes respiratory gas from the lungs and which gas occupies anatomical dead space at the end of the exhalation phase of the breathing cycle.

[0578] Having regard to Figures 1 to 4, the general form comprises a patient interface 10 which includes a cushion module 20, a frame 30 and a conduit connector 40. The conduit connector 40 comprises structural components for connecting the cushion module to a source of respiratory gas, such as a ventilator, humidifier, flow generator or wall source. In this embodiment, the conduit connector 40 is integrally formed with the frame 30. In this embodiment, the patient interface 10 is in the form of a sub-nasal full-face mask where the cushion module 20 comprises a seal member 218 and a housing 202. Collectively, the seal member 218 and a housing 202 form an outer wall 288 of the cushion module 20.

[0579] The seal member 218 is formed of soft, resilient material, such as a elastomer, or more specifically such as a silicone. The seal member 218 includes an oral opening 220 and a nare opening 222. When fitted to a patient, the oral opening 220 circumscribes the patient's mouth and a patient-contact surface 290 of the outer wall forms a seal about the mouth. Accordingly, respiratory gas at elevated pressure can be delivered to the patient via the oral opening 220. The seal member 218 comprises a nare-sealing portion 224 in which is located the nare opening 222. The nare-sealing portion 224 has the form of a nasal cradle. The patient-contact surface 290 includes the nare-sealing portion 224 and a lip superior wall portion 268 located between the oral opening 220 and the nare opening 222. The lip superior wall portion 268 is defined between the oral opening 220 and the nare opening 222 and the between the lateral sides of the nare opening 222. The nare-sealing portion 224 is arranged to contact the underside of the patient's nose and to form a seal with the patient's nares so that respiratory gas at elevated pressure can be delivered to the patient via the nare opening 222.

[0580] The nare opening 222 is located to align with the nares of the patient when the patient interface 10 is fitted. For the patient interface 10, the total area of the one or more nare openings may be in the range of 130 to 340 mm2. Alternatively, the total area of the one or more nare openings may be in the range of 140 to 330 mm2or in the range of 150 to 320 mm2.

[0581] Although this embodiment of the cushion module 20 includes a single oral opening 220 and a single nare opening 222, it will be appreciated that other embodiments may include more than one oral opening 220, more than one nare opening 222 or multiple oral openings 220 and multiple nare openings 220. The cushion module 20 defines an interior volume which comprises a first chamber 226 and a second chamber 228. The second chamber 228 comprises an upper portion of the internal volume of the cushion module 20. The first chamber 226 comprises a lower portion of the internal volume of the cushion module 20. The first and second chambers 238, 240 are separated by a dividing wall 230 (Figure 4). As shown in Figures 3 and 4, the oral opening 220 is associated with the first chamber 226 to enable transfer of respiratory gas between the first chamber 226 and the patient's mouth. An inlet, and in the illustrated embodiment the inlet opening 292 of the sleeve 212 (Figure 6), is also associated with the first chamber 226. The nare opening 222 is associated with the second chamber 228 to enable transfer of respiratory gas between a second chamber 228 and the patient's nares. The second chamber 228 includes an outlet. As described above, the outlet may be configured to deliver respiratory gas from the second chamber 228 to an exhaust conduit of a dual-limb patient interface or the outlet may be a bias vent. In the cushion module 20, the outlet is provided by the bias vent holes 216. The bias vent holes 216, therefore, enable respiratory gas to be vented from the cushion module to external of the cushion module. In the cushion module 20, the bias vent holes 216 vent the respiratory gas to the ambient atmosphere.

[0582] The housing 202, as shown in Figure 6 without the seal member 218, is formed of a substantially rigid plastics material. The housing 202 provides structural support to the seal member 218. Additionally, the housing 202 provides an interface for connecting the seal member 218 to the frame 30 and to the conduit connector 40.

[0583] The housing 202 may alternatively be formed of any other suitable material such as a foam, textile, or an elastomer material. In situations where additional rigidity is required the housing 202 may be reinforced by sections of increased local thickness, sectional rigidity, or by the addition of rigid components of a secondary material such as a plastic.

[0584] The housing 202 includes a sleeve 212 that is sized and shaped to connect with the frame 30. The sleeve 212 forms an inlet opening 292 through which respiratory gas can be communicated from the conduit connector 40 to interior of the cushion module 20. The sleeve 212 includes key formations 214 that interact with the frame 30 to ensure correct alignment of the frame 30 with the housing 202 when they are fitted together.

[0585] The housing 202 includes a series of tabs 204 which project outwardly around its perimeter. The outer ends of the tabs 204 are linked to a bead 206 which runs continuously across all of the tabs 204, thereby forming a series of discrete outer overmould windows 208 between the tabs 204 and the bead 206. The seal member 218 is integrally formed with the housing by over-moulding a resilient material onto the housing 202 to fill the outer over-mould of windows 216. Therefore, the tabs 204 and the bead 206 become embedded in the resilient material and are mechanically interlocked with the seal member 218. The seal member 218 and the housing 202, therefore, form a unitary cushion module 20 structure. The housing 202 includes an outlet for exhausting gas from the second chamber 228 to external of the cushion module 20. The outlet may include one or more openings for exhausting respiratory gas. For example, the outlet may comprise one or more openings for exhausting respiratory gas from the second chamber 228 to an exhaust gas conduit of a dual-limb patient interface. However, in this embodiment, the outlet includes a bias vent. The bias vent includes a group of bias vent holes 216 through the housing 202. The bias vent holes 216, in this embodiment, exhaust respiratory gas to the ambient atmosphere.

[0586] The housing 202 further includes a series of inner over-mould windows 210 through which the seal member 218 is also over-moulded with the housing 202. The inner overmould windows 210 are located in a region of the housing 202 that is within the perimeter formed by the outer over-mould windows 208. The bias vent holes 216 are bound on one side by the outer over-mould windows 208 and on another side by the inner over-mould windows 210. As shown in Figure 6, the bias vent holes 216 are surrounded by the outer over-mould windows 208 and the inner over-mould windows 210. The material used to form the seal member 218 flows through the inner and outer over-mould windows 208, 218 during moulding so that the material conforms to the shape of the housing 202 and the windows 216, 218 prior to solidifying or curing. Having the material extend through the windows 216, 218 results in a mechanical connection with the housing 202. The windows 216, 218 may take the form of apertures which extend completely through the housing 202.

[0587] The dividing wall 230 (Figure 4) partitions the cushion module 20 internally to define the first chamber 226 and the second chamber 228. The dividing wall 230 separates the first chamber 226 from the second chamber 228 by extending all the way across the internal volume of the cushion module 20. In other words, the perimeter of the dividing wall 230 seals with the outer wall 288. A meeting line 282, which notionally shows where the dividing wall 230 meets the outer wall 288, is shown in Figures 3 and 7. In particular, the dividing wall 230 extends all the way across between the first chamber 226 and the second chamber 228. The sealing of the first chamber 226 from the second chamber 228 means that the only flow of respiratory gas between the first chamber and the second chamber is through the flow directors 246. So, while the dividing wall 230 seals the first chamber 226 from the second chamber 228, the dividing wall 230 permits respiratory gas to flow from the first chamber 226 to the second chamber 228 only via the flow directors 246 (see Figures 10 to 16). The dividing wall 230 includes a forward panel 232 that links to the distal side 938 of the outer wall 288 and is distal of the deformation panel 294. The dividing wall 230 includes a rearward panel 234 that links to the proximal side 940 of the outer wall 288 and is proximal of the deformation panel 294. For the most part, the deformation panel 294 separates the forward panel 232 from the rearward panel 234. However, the forward and rearward panels 232, 234 meet along a notional line 922 that extends laterally beyond the deformation panel 294 to the outer wall 288. The notional line 922 is contiguous with the link between the forward panel 232 and the deformation panel 294.

[0588] The dividing wall 230 of the cushion module 20 has a generally planar transverse profile. This is shown by the meeting line 282 between the dividing wall 230 and the outer wall 288 in Figures 3 and 7 extending below the bias vent holes 216 and across the lip superior wall portion 268. The planar profile reduces vertical travel of the dividing wall 230 (and the flow directors 246) which contributes to maintaining a spacing between the flow directors 246 and the nare opening 222 to reduce the risk of the flow directors 246 contacting the patient. The planar profile makes this contribution for other configurations of the dividing wall 230.

[0589] The generally planar transverse profile of the dividing wall 230 results in the given volume ratio of the second chamber 228 to the first chamber 226. It will be appreciated, however, from the embodiments disclosed below that alternative configurations of the dividing wall 230 may be adopted in place of the generally planar transverse profile. Those different configurations result in different volume ratios of the second chamber 228 to the first chamber 226. The patient interface 10 has a volume ratio of the second chamber to the first chamber is in the range of 0.05: 1 to 0.7: 1. This volume ratio covers each of the embodiments disclosed here. However, without wishing to be limited to that particular range, the volume ratio of the second chamber 228 to the first chamber 226 may be greater than 0.1: 1, greater than 0.15: 1, greater than 0.2: 1, greater than 0.25: 1, or about 0.3: 1. Furthermore, the volume ratio of the second chamber 228 to the first chamber 226 may be less than 0.65: 1, less than 0.6: 1, 0.55: 1, less than 0.5: 1, less than 0.45: 1, less than 0.4: 1, or less than 0.35: 1.

[0590] The volume of the first chamber 226 may be in the range of 90 to 160 cm3. However, without wishing to be limited to that particular range, the volume of the first chamber 226 may be greater than 95 cm3, greater than 100 cm3, greater than 105 cm3, greater than 110 cm3, greater than 115 cm3or about 120 cm3. Furthermore, the volume of the first chamber 226 may be less than 155 cm3, less than 150 cm3, less than 145 cm3, less than 140 cm3, less than 135 cm3, less than 130 cm3, or less than 125 cm3.

[0591] The volume of the first chamber 226 includes the volume of gas flow passages 296 through the one or more flow directors 246. Furthermore, the outer wall 288 may include a sleeve 212 which is configured to connect with a frame 30 or a respiratory gas conduit and the volume of the first chamber 226 excludes the volume defined by the sleeve 212.

[0592] Figures 10, 11 and 15 show the dividing wall 230 seals with the outer wall 288 between the nare opening 222 and the oral opening 220 across the entire width of the lip superior wall portion 268. In other words, the dividing wall 230 seals with the outer wall 288 at a location spaced from the nare opening 222. It can further be seen in Figures 10 and 11 that the dividing wall 230 seals with the outer wall 288 closer to the nare opening 222 than to the oral opening 220. In other words, the seal between the dividing wall 230 and the lip superior wall portion 268 is located in an upper half of the lip superior wall portion 268, having regard to an upright orientation of the patient interface 10.

[0593] The way in which the cushion module 20 delivers respiratory gas to a patient and removes excess respiratory gas and removes exhaled respiratory gas is similar to the method described in the international patent application PCT / NZ2020 / 050072, with reference in particular to Figures 45 to 47 and the associated description. By way of summary in reference to the cushion module 20, the supply of respiratory gas to the patient is as follows. An accelerated stream of respiratory gas is delivered to a patient to provide anatomical dead space flushing. This involves delivering respiratory gas at an elevated pressure to the first chamber 226 of the cushion module 20 via the inlet associated with the first chamber 226. The first chamber 226 supplies the respiratory gas to the mouth of a patient via the oral opening 220, and to the second chamber 228 via the flow directors 246. The second chamber 228 supplies the respiratory gas to the nares of the patient via the nare opening 222. The flow of respiratory gas towards the nares is accelerated through the flow directors 246. The flow directors 246 reduce in cross-sectional area toward the nare opening 222. The accelerated respiratory gas can then be delivered to the nares of a patient. The accelerated flow of respiratory gas occurs at the same time that respiratory gas is available for delivery to the mouth from the first chamber 226. Excess respiratory gas from the first chamber 226, exhaled respiratory gas and flushed respiratory gas flows into the second chamber 228 and then flow through the outlet associated with the second chamber 228. In some circumstances, anatomical dead space flushing occurs by respiratory gas entering the mouth, flowing through the top of the throat and the nasal cavity, out through the nares and into the second chamber 228. In some circumstances, the anatomical dead space flushing occurs by respiratory gas entering the nares from the second chamber 228, flushing the nasal cavity and then exiting via the nares into the second chamber 228.

[0594] One design consideration for the seal member 218 involves balancing patient comfort and treatment performance. Treatment performance is improved by ensuring that the flow structures which direct respiratory gas into the nares, such as the flow directors 246 in this embodiment, retain their shape and remain correctly oriented when the patient interface is fitted to a patient. Patient comfort is an important consideration because the facial contact points affected by the patient interface 10 in use include highly sensitive areas, such as the septum and the philtrum. In this embodiment, the dividing wall 230 is lower within the internal volume of cushion module 20. The lower positioning of the dividing wall 230 shifts the join between the dividing wall 230 and the outer wall 288 away from the nare-sealing portion 224. The lower location of the dividing wall 230 results in the joins between the dividing wall 230 and the outer wall 288 being away from the highly sensitive nasal contact regions on the underside of the nose. This shift in the location of the dividing wall 230 join with the outer wall 288 is anticipated to improve patient comfort.

[0595] The design consideration mentioned above may be further assisted by forming the dividing wall 230 with additional support structures which assist to retain the shape and orientation of the flow directors 246. Adopting such support structures as part of the dividing wall 230 means that the maintaining the shape and orientation of the flow directors 246 to be therapeutically effective doesn't rely on connection of the flow directors 246 to the outer wall 288 for support. In this embodiment, for example, the flow directors 246 in the cushion module 20 are spaced from the outer wall 288. In other embodiments, the flow directors may be linked to the outer wall 288 for support. It will be appreciated that, in those embodiments, the additional support structures as part of the dividing wall 230 enable the links between the flow directors 230 and the outer wall 288 to be reduced. The reduced links with the outer wall 288 reduce the contact between internal structures of the cushion module 20 and the patient-contact surface 290. This reduces the size of pressure points acting on the patient's face. Furthermore, the lower positioning of the dividing wall 230 provides the second chamber 228 with a greater volume. The greater volume provide more space for structures within the second chamber 228 (such as the flow directors 246) to be further supported and reinforced by the dividing wall 242.

[0596] The flow directors 246 extend into the second chamber 228. In other embodiments, the flow directors 246 may extend into the first chamber 226. In a further embodiment, the flow directors 246 may extend into the first chamber 226 and the second chamber 228.

[0597] The body 248 of each flow director 246 is spaced from the outer wall 288 so that the entire perimeter of the dividing wall 230 joins with the outer wall 288. Said another way, the body 248 of each flow director 246 may be located in a central region of the dividing wall 230 such that each flow director 246 is spaced from the perimeter of the dividing wall 230. The central region may coincide with the centre of the dividing wall 230 or may be off-set from the centre of the dividing wall 230. In each embodiment, however, the first chamber 226 is separated from the second chamber 228 by the dividing wall 230 and the flow directors 246.

[0598] The flow directors 246 (Figure 11) define a gas flow passage 296 from the first chamber 226 to the second chamber 228 and the flow directors 246 surround the gas flow passage 296. Each flow director 246 comprises a body 248 including a first opening 250 and a second opening 252. The first opening 250 of each flow director 246 opens into the first chamber 226. The second opening 252 of each flow director 246 opens into the second chamber 228. This means that the flow directors 246 are the only avenue for respiratory gas to flow between the first chamber 226 and the second chamber 228.

[0599] In alternative embodiments there may be a secondary flow path between the first chamber 226 and second chamber 228 to enable flow through the dividing wall in addition to through the one or more flow directors 246.

[0600] In this embodiment, the entire seal member 218 is integrally formed and is overmoulded onto the housing 202 in a single piece construction. This integral moulding of the dividing wall 230 with the outer wall 288 forms a gas-tight join where the dividing wall 230 meets the outer wall 288. This includes where the dividing wall 230 meets the housing 202, which defines part of the outer wall 288. The same applies with the flow directors 246 being integrally formed as part of the seal member 218. That is, the body 248 of each flow director 246 is integrally formed with the dividing wall 230 to form a gas-tight join. The second openings 252 are positioned to direct respiratory gas towards and / or through the nare opening 222. This directs respiratory gas to the patient's nares from the first chamber 226 via the second opening 252, through the second chamber 228 and through the nare opening 222. Such directed respiratory gas assists breathing during the respiratory cycle and contributes to anatomical dead-space flushing in the nasal cavity of a patient.

[0601] The position and shape of the second openings 252 affects the flow of respiratory gas into the second chamber 228 and through the nare opening 222. In the embodiment shown in Figures 9 and 12 to 16, each flow director 246 has the second opening 252 within the second chamber 228 and the second opening 252 is spaced from the nare opening 222. The second opening 252 is defined by a rim 254. In this embodiment, that the rim 254 is contoured so that at least a portion of the rim 254 has a substantially consistent spacing from the nare opening 222. In other embodiments, the spacing of the rim from the nare opening 22 may vary.. The rim 254 of each second opening 252 extends further from the dividing wall 230 at a laterally outer side of the flow director 246 than the rim 254 extends from the dividing wall 230 at a laterally inner side of the flow director 246. This means that the rim 254 is recessed further from the nare opening 222 at a laterally inner side of the flow director 246 than the rim 254 is recessed from the nare opening 222 at the laterally outer side of the flow director 246. The lower height of the rim relative to the dividing wall 230 on the laterally inner side of each flow director 246 assists with the flow of respiratory gas from the first chamber 226 into the second chamber 228. The higher height of the rim relative to the dividing wall 230 on the laterally outer side of each flow director 246 assists with directing respiratory gas from the first chamber 226 through the second chamber 228 and through the nare opening 222. In another embodiment, the rim 254 is recessed furthest from the nare opening 222 at a point between the laterally outer side of the flow director 246 and the laterally inner side of the flow director 246 such that, in vertical cross-section, the rim 254 is concave or curved inwardly. In other embodiments, the rim 254 extends from the body by a generally constant distance. In such embodiments, the rim 254 defines a generally flat planar second opening 252 of the flow director 246 into the second chamber 228.

[0602] The recessed position of the second opening 252 relative to the nare opening 222 enables excess respiratory gas from the first chamber 226 (including exhaled respiratory gas from the mouth) to pass into the second chamber 228 and to be exhausted from the cushion module 20 through an outlet. As described above, the outlet may exhaust the respiratory gas from the second chamber 228 to an exhaust conduit of a dual-limb patient interface or the outlet may be a bias vent whereby the respiratory gas is exhausted externally of the patient interface 10 through the bias vent holes 216.

[0603] The nare opening 222 is defined, at the outer wall 288 of the seal member 218, by a rim 286. However, given that the second opening 252 is recessed from the rim 254, the spacing between the second opening 252 and the rim 286 enables respiratory gas to flow from the first chamber 226 to the second chamber 228 and then out through the bias vent holes 216 to ambient atmosphere. Alternatively, the outlet from the second chamber may be linked to an exhaust conduit of a dual-limb patient interface. This flow of respiratory gas through the bias vent holes 216 (of through the outlet) generally occurs during part of the exhalation phase of the respiratory cycle. For example, when the patient exhales through their nose (excess respiratory gas delivered from a source to the first chamber 226 flows into the second chamber 228). Alternatively, the flow of respiratory gas involves excess respiratory gas flowing from the first chamber 226 to the second chamber 228 and then through an outlet (in this embodiment, the outlet includes the bias vent holes 216) when the patient exhales through their mouth. The exhaled respiratory gas flows from the mouth and into the first chamber 226 and then into the second chamber 228, along with excess respiratory gas delivered from a source. At times during inhalation through the nose or during nasal cavity dead space flushing, the respiratory gas may flow from the first chamber 226, into the second chamber 228 and then through the nare opening 222 and into the nares of the patient.

[0604] As shown in Figure 11, the body 248 of each flow director 246 includes a lower body portion 256 and a upper body portion 258. The lower body portion 256 has a wall thickness that is greater than the wall thickness of the upper body portion 258. The wall thickness decreases from the lower body portion 256 to the second opening 252. This is evident in the stepped profile of the body 248 as shown in Figures 10 and 13. The cross-sectional view of the body in Figure 11 also shows the stepped profile of the body 248. In other embodiments, however, the body 248 may have a uniform wall thickness or the wall thickness in at least part of the body 248 may decrease in the direction from the first opening 250 to the second opening 252. Furthermore, the body 248 includes a tapered respiratory gas flow passage 296 so that the second opening 252 has a cross- sectional area that is less than the cross-sectional area of the first opening 250. The reduction in the cross-sectional area of the respiratory gas flow passage 296 between the first opening 250 and the second opening 252 has the effect of accelerating respiratory gas toward the nare opening 222 so as to deliver an accelerated stream of respiratory gas to the nares. In this embodiment, the lower body portion 256 and the upper body portion 258 have an elliptical shape in cross-section generally parallel to the plane of the dividing wall 230 around where the flow director 246 is located. Alternative flow director shapes are described below in relation to alternative embodiments of the seal member. Those alternative embodiments of the flow directors may be adopted into the seal member 218 described above. Further alternative flow directors are described in international application PCT / NZ2022 / 050001 (published as WO2022 / 158987) as detailed below. Any one of those alternative embodiments for the flow directors may be utilised in the seal member 218 described above or any one of the seal members described below.

[0605] In the seal member 218 shown in Figures 6 to 16, the patient interface 10 includes two flow directors 246 that are spaced apart. That is, the two flow directors 246 comprise two separate structures. They do not share a common wall which defines the gas flow passage 296 through each of the flow directors 246. The flow directors 246 are spaced apart by a gap through which respiratory gas from the first chamber 226, and exhaled respiratory gas from the nares entering the second chamber 228 via the nare opening 222, can flow into the second chamber 228. In this embodiment, the rim 254 of each flow director 246 extends away from the dividing wall 230 less on the side of the flow director 246 that has the gap than the rim 254 extends away from the dividing wall 230 on the side of the flow director 246 that is remote from the gap. In other embodiments, the rim 254 extends away from the dividing wall 230 the same extent at each side of the flow directors 246. In this embodiment, the flow directors 246 are configured with the lateral outer side of the rims 254 adjacent to a laterally outer rim 286 of the nare opening 222 having regard to a direction of gas flow towards the flow director 246.

[0606] More specifically, the rim 254 is located laterally inwardly of the laterally outer rim 286 of the nare opening 222. However, in other embodiments, the rim 254 may be located laterally outwardly of the laterally outer rim 286 of the nare opening 222 or the lateral outer side of the rim 254 may be aligned with a laterally outer rim 286 of the nare opening 222 having regard to a direction of gas flow from the flow director 246.

[0607] The spacing apart of the flow directors 246 to the laterally outer side of the nare opening 222 is anticipated to improve patient comfort due to a reduced chance of the flow directors 246 contacting points of the outer wall 288 at the patient's septum and philtrum. The lateral spacing of the contact points will shift contact points, should they occur, away from the sensitive septum and philtrum areas. The anticipated improvement in comfort should contribute to greater compliance with treatments and should reduce pressure sores. Furthermore, it is believed that the lateral position of each of the two flow directors 246 with regards to the nare opening 222 will improve the likelihood of the flow directors 246 aligning with the nares of the patient and therefore delivering sufficient flow. This is because the laterally spaced position of the flow directors 246 lowers the chance that a patient with a wide or large septum (which would be located centrally with respect to the nare opening 222) will impede flow from exiting the flow directors 246.

[0608] A bead 262 circumscribes the rim 286 of the nare opening 222 on an inner surface of the seal member 218. The bead 262 comprises, in this embodiment, a region of increased wall thickness as shown in Figures 13 to 15. The increased thickness of the rim 286 increases the ability of the rim 286 to resist excessive outwards deformation, otherwise known as a blow-out which can occur when the patient interface 10 receives high levels of pressurised respiratory gas from a gas source. The increased thickness of the rim 286 also increases the ability of the rim 286 to resist undesired deformation which may occur when the patient interface 10 is fitted to the patient.

[0609] The dividing wall 230 is configured to preferentially deform in a way that reduces the likelihood of the second chamber 228 and the nare opening 222 being occluded.

[0610] The forward panel 232 includes a first resilient region 236. The rearward panel 234 includes a second resilient region 238. The rearward panel further includes lateral sides 800 (Figures 12 and 15). The flow directors 246 are within a footprint of the second resilient region 238. In other words, the flow directors 246 extend from the portion of the rearward panel 234 comprising the second resilient region 268. Additionally, the flow directors 264 are spaced from the lip superior wall portion 268 and spaced from the transition portion 916. Alternatively, the flow directors 246 may be partly within the second resilient region 238. Further alternatively, the flow directors may be linked to the outer wall 288, optionally at the lip superior wall portion 268 or further optionally adjacent the nare opening 222.

[0611] The deformation panel 294 includes a straight section 926 and a bend 928. These are shown in Figure 10 in cross-sectional profile. The bend 928 is located between the second resilient region 238 and the straight section 926 and the straight section 926 is located between the bend 928 and the first resilient region 236. The bend 928 is an inflection point between the second resilient region 238 and the straight section 926. The deformation panel 294 structurally decouples the first resilient region 236 from the rearward portion 934 or from the second resilient region 238. The decoupling occurs because the deformation panel 294 accommodates translation of the second resilient region 238 in the proximal-distal direction relative to the first resilient region 236.

[0612] The second resilient region 238 has a wall thickness that is greater than the wall thickness of the remainder of the rearward panel 234. The second resilient region, therefore, is relatively resistant to deformation compared to the deformation panel 294. The first resilient region 236 also has a wall thickness that is greater than the wall thickness of the deformation panel 294. The greater wall thickness of the first and second resilient regions 236, 238 makes them more resistant to deformation than the deformation panel 294. Accordingly, the deformation panel 294 will deform in preference to the first resilient region 236 and the second resilient region 238. While the higher resilience of the first and second resilient regions 236, 238 relative to the resilience of the deformation panel 294 is attributable, in this embodiment, to the wall thickness of the first and second resilient regions 236, 238, in other embodiments the higher resilience of the first and second resilient regions 236, 238 relative to the resilience of the deformation panel 294 may be attributable to different materials from which the first and second resilient regions 236, 238 are formed compared to the material of the deformation panel 294 or may be attributable to combinations of different materials from which the first and second resilient regions 236, 238 are formed compared to the material of the deformation panel 294.

[0613] The deformation of the patient interface 10 in use involves a force being applied to the patient-contact surface 290 such that the second resilient region 238 is displaced toward the first resilient region 236 in the distal direction. This causes the deformation panel 294 to fold about its line of connection with the first resilient region 236. The vertical dimension of the straight section 926 determines the extent of deformation that the deformation panel 294 can accommodate. More specifically, a larger vertical dimension of the straight section is able to accommodate more displacement of the second resilient region 238 in the distal direction. For the cushion module 230, the vertical dimension of the deformation panel 294 is selected to accommodate the anticipated displacements of the second resilient region 238 toward the first resilient region 236 in use for the target population of users.

[0614] During use, when the patient interface 10 is fitted, force will be applied to the patient contact surface 290 to account for differing facial geometries, headgear preferences and pressure settings. These forces and the locations they are applied to will differ. The configuration described above, however, focusses the forces and deflection applied to the patient-contact surface 290 into the deformation panel 294 to provide a predictable collapse and rebound movement. The predictable buckling pattern achieved by the deformation panel 294 allows the patient interface 10 to be designed in such a way that, when forces are applied to the patient-contact surface 290 of the seal member 218, the resulting deformation and compression that occurs in the elastomeric material that forms the seal member 218 happens in such a way that the nare opening 222 and the second openings 252 of the flow directors 246 are likely to remain substantially unobstructed. Furthermore, the positioning of the nare opening 222 and the second openings 252 relative to each other will be substantially maintained during deformation. Without this preferential deformation, collapse of the dividing wall 230 would be unpredictable, potentially leading to inconsistent flow through the second openings 252 or inconsistent positioning of the second openings 252 relative to the nare opening 222 and / or patents nares. This would cause inconsistencies in the therapy achieved, comfort, fitting procedure and in overall performance both between uses for the same patient and between different patients.

[0615] In a variation of this embodiment, the seal member 218 may have more than one deformation panel 294. For example, the additional deformation panels 294 may be incorporated into the dividing wall 230 or may be incorporated into the seal member 218 at other locations that enable the second chamber 228 and / or nare opening 222 and the second openings 252 of the flow directors 246 to substantially retain their shape and alignment.

[0616] The geometry of the deformation panel 294 and its thickness are selected so that the cushion module 20 can accommodate a wide range of facial geometries and deformation forces associated with the application and use of the patient interface. However, it is possible for different cushion modules to be produced to fit specific ranges of facial geometries which fall toward the ends of the facial geometry anthropometric spectrum. For example, the cushion module may be produced in a number of different sizes corresponding to sections of the anticipated population of the intended users.

[0617] The first resilient region 236 is more resilient that the deformation panel 294 to ensure that the deformation panel 294 deforms in preference to the first resilient region 236. The resilience of the first resilient region is partly due to being formed with a greater wall thicknesses than the wall thickness of the remainder of the forward panel 232. The greater resilience of the first resilient region 236 compared to the deformation panel 294 is also partly due to the connection of the first resilient region 236 to the relatively rigid housing 202. This connection contributes to the resilience of the first resilient region 236 because the housing 202 provides an anchor point that assists to retain the orientation of the first resilient region 236.

[0618] Additionally, the difference in wall thickness enables the first resilient region 236 and the deformation panel 294 to be formed of the same material. This enables the seal member 218 to be formed of a single material. However, it will be appreciated that the first resilient region 236 may be stiffened by alternative means provided that the deformation panel 294 preferentially deforms when a force is applied to the seal member 218. For example, the first resilient region 236 may be formed of more resilient materials (such as a different grade of silicone or a plastic material) or may have a different structure. Alternatively, the first resilient region 236 is an integral portion of the housing 202 formed of the plastics material of the housing 202 and the deformation panel 294 is an integral portion of the seal member 218 formed of the silicone or other elastomer of the seal member 218 and connected to the first resilient region 236 via an over-moulding process that forms the seal member 218.

[0619] The first resilient region 236 has a wall thickness that is also greater than the wall thickness of the second resilient region 238. The great wall thickness of the first resilient region 236 compared to the wall thickness of the second resilient region 238 ensures that the second resilient region 238 deforms in preference to first resilient region 236. Accordingly, the greater resilience of the first resilient region 236 relative to the resilience of the deformation panel 294 and the second resilient region 238 (on account of their relatively smaller wall thicknesses) reduces the chances of the bias vent holes 216 being occluded when the dividing wall 230 deforms to accommodate a force placed on the patient-contact surface 290.

[0620] As shown in Figures 10 and 11, the first resilient region 236 is at a level that is lower than a level of the second resilient region 238 having regard to a generally upright orientation of the patient interface. This is evident from a connection between the first resilient region 236 and the deformation panel 294 being at a level that is lower than the level of a connection between the second resilient region 238 and the deformation panel 294. Furthermore, the second resilient region 238 is linked to the lip superior wall portion 268. The difference in levels between the first resilient region 236 and the second resilient region 238 with the deformation between them enables the seal member 218 to absorb deformation forces imparted on the patient-contact portion 290, including the lip superior wall portion 268, by way of the second resilient region 238 translating in the proximal-distal direction without interference from the first resilient region 236. The second resilient region 238 translates at a level above the first resilient region 236. Depending on the extent of translation, part of the second resilient region 238 may translate over part of the first resilient region 236.

[0621] The seal member 218 includes a first distal opening 902 in the first chamber 226 which is defined by a first rim 904. The seal member 218 also includes a second distal opening 906 in the second chamber 228. The second distal opening 906 is defined by an upper rim portion 908 and a lower rim portion 910 which meet at respective lateral edges, having regard to an upright orientation of the patient interface. The first distal opening 902 extends laterally beyond the lateral edges of the second distal opening 906. In other words, the first distal opening 902 is wider than the second distal opening 906, having regard to an upright orientation of the patient interface 10. The first rim 904 of the first distal opening 902 is formed by over-moulding part of the seal member 218 through the over-mould windows 208 of the housing 202. Such over-moulding forms a mechanical connection between the housing 202 and the seal member 218. The lower rim portion 910 of the second distal opening 906 is formed by over-moulding part of the seal member 218 through the over-mould windows 210 and the upper rim portion 908 is formed by over-moulding part of the seal member 218 through the over-mould windows 208 which are adjacent to the bias vent holes 216 and are between the lateral ends of the over-mould windows 210.

[0622] Part of the first resilient region 236 meets the lower rim portion 910 of the second distal opening 906 along the length of the lower rim portion 910. Laterally beyond the lateral edges of the second distal opening 906, the first resilient region 236 meets the outer wall 288 adjacent to part of the contour of the first rim 904 of the first distal opening 902. This can be seen in Figure 7 in the form of a line 282 showing where the dividing wall 230 meets with the distal side 938 of the outer wall 288. The line 282 also appears in Figure 3 to show where the dividing wall 230 meets the outer wall 288 on a proximal side 940 of the patient interface 10.

[0623] The first resilient region 236 meets the outer wall 288 along the line 282 which follows the lower rim portion 910 between the lateral edges of the second distal opening 906. As shown in Figure 12, the first resilient region 236 includes a central region 240 between lateral edges of the second distal opening 906. The first resilient region 236 includes a second chamber surface 272 that is exposed to the second chamber 228 (Figures 10 and 12). The second chamber surface 272 of the first resilient region 236 in the central region 240 is inclined relative to the deformation panel 294 at an angle that is less than the angle between the deformation panel 294 and the lateral regions 242 of the first resilient region 236. Part of the first resilient region 298 includes a cross- sectional shape in the lateral direction that is W-shaped, as shown in Figure 13. In an alternative embodiment, between lateral edges of the second distal opening 906, the first resilient region 298 may include a lateral profile that is U-shaped.

[0624] At least part of the first resilient region 236 decreases in wall thickness in a distal direction between the link with the deformation panel 294 and the connection with the outer wall 288 at the lower rim portion 910 (Figure 10). The decreasing wall thickness in this illustrated embodiment occurs in the central region 240 of the first resilient region 236. However, in alternative forms, at least part of the first resilient region 236 may increase in wall thickness in a distal direction between the link with the deformation panel 294 and the connection with the outer wall 288. In further alternative forms, at least part of the first resilient region 236 includes a generally constant wall thickness in a distal direction between the link with the deformation panel 294 and the connection with the outer wall 288.

[0625] The deformation panel 294 includes a second chamber surface 298 exposed to the second chamber 228. The second resilient region 238 includes a second chamber surface 272 exposed to the second chamber 228. At least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the second chamber surface 272 is inclined at an obtuse angle relative to the second chamber surface 298 of the deformation panel 294 at a location where they meet (Figure 10). Given the orientation of the second chamber surface 272 of the first resilient region 236, a centreline in the proximal-distal direction across the second chamber surface 278 of the second resilient region 238 is parallel to or within + / - 20° of a centreline in the proximal-distal direction across the second chamber surface 272 of the first resilient region 268. Alternatively, a centreline in the proximal-distal direction across the second chamber surface 278 of the second resilient region 238 may be parallel to or within + / - 10° of a centreline in the proximal- distal direction across the second chamber surface 272 of the first resilient region 264.

[0626] The deformation panel 294 (as shown in Figures 10, 11, 14 and 15) extends furthest in the distal direction at a centreline of the seal member 218 in the proximal-distal direction. From that centreline and in the lateral direction, the deformation panel curves proximally (Figure 12). The proximal curvature of the deformation panel 294 matches the curvature of at least part of the second resilient region 238 (Figure 10). Also, as shown in Figures 10, 13 and 15, the spacing between the first and second resilient regions 268, 264 where they respectively link to the deformation panel 294 decreases in a direction laterally outwardly from the centreline in the proximal-distal direction. However, in other forms, the spacing between the first and second resilient regions 236, 238 where they respectively link to the deformation panel 294 may decrease, may vary, or may be constant in a direction laterally outwardly from a centreline in the proximal-distal direction through the seal member 218. In other words, a sequence of cross-sections in the proximal-distal direction taken at points increasingly further laterally outwardly from the centreline in the proximal-distal direction through the seal member 218 may show that the dimension of the deformation panel 294 in the vertical direction decreases, varies or is constant. As shown in Figure 12, the deformation panel 294 extends laterally beyond the second resilient region 238. Lateral sides 800 of the rearward panel 234 link with the deformation panel 294 laterally beyond the second resilient region 238. The vertical spacing between the first resilient region 236 and the lateral sides 800 where they respectively link to the deformation panel 294 decreases in a direction laterally outwardly from the centreline in the proximal-distal direction.

[0627] However, the deformation panel 294 terminates at a location spaced from the outer wall 288 and the lateral sides 800 extend laterally beyond the termination locations of the deformation panel 294. The lateral sides 800 of the dividing wall 230 meet the outer wall 288 along the line 282 in Figure 3 at a level in a band 820 (Figure 3) defined between the lowest level the nare opening 222 and uppermost level of the oral opening 220. In regard to the first resilient region 236, part of the first resilient region 236 meets the outer wall outside of the band 820 and another part of the first resilient region 236 meets the outer wall within the band 820. In the seal member 218, part of the first resilient region 236 that is laterally outside the lateral edges of the second distal opening 906 meets the outer wall 288 within the band 820.

[0628] The transfer of deformation forces into the deformation panel 294 is contributed to by the second resilient region 238 which is formed as part of the dividing wall 230. The second resilient region 238 comprises a thickened wall section of the dividing wall 230 located between the lip superior wall portion 268 and the deformation panel 294 as shown in Figures 10, 12 and 13. The second resilient region 238 meets the outer wall 288 partly at the lip superior wall portion 268. The second resilient region 238 also meets the outer wall 288 partly laterally outside the lip superior wall portion 268. Furthermore, the second resilient region 238 meets the outer wall 288 at the lip superior wall portion 268 closer to the one or more nare openings 222 that the one or more oral openings 220 in the vertical direction. The level at which the second resilient region 238 meets the lip superior wall portion 268 varies in different embodiments. However, second resilient region 238 may meet the lip superior wall portion 268 along a line that is spaced from the one or more nare openings 222 by a distance that is in the range of 1 to 4 times the wall thickness of the second resilient region 238. The second resilient region 238 includes a uniform wall thickness. However, in alternative forms, the second resilient region 238 may have a non-uniform wall thickness. Either way, the wall thickness of the second resilient region 238 is greater than the wall thickness of the deformation panel 294.

[0629] The dividing wall 230 includes lateral sides 800 extending laterally of the second resilient region 238. The lateral sides 800 have a wall thickness that is less than the wall thickness of the second resilient region 238. A smooth transition between the different wall thicknesses of the second resilient region 238 and the lateral sides 800 is provided by a transition portion 916 (Figures 10, 12 and 13). The transition portion 916 tapers in wall thickness from the second resilient region to the lateral sides 800. A distal end 914 of the transition portion 916 meets the deformation panel 294. However, in an alternative embodiment (Figure 17), the second resilient region 238 is spaced from the deformation panel 294 entirely. In each respective embodiment shown in Figure 12 and in Figure 17, the transition portion 916 includes first portions 918 disposed laterally outwardly of the flow directors 246 and includes a distally extending curve portion 920 joining the first portions 918. Accordingly, the transition portion 916 has a U-shape in the plane of the dividing wall 230. The first portions 918 are parallel to each other. In the embodiments shown in Figures 10 and 17, the first portions 918 extend from the lip superior wall portion 268. However, in alternative embodiments, the first portions 918 may extend from the outer wall 288 at locations laterally outwardly from the lip superior wall portion 268. In an alternative embodiment, the transition portion 916 may be a continuous curve that joins with the lip superior wall portion 268. In another embodiment, the transition portion 916 may surround the second resilient region 238 and may be spaced from the lip superior wall portion 268.

[0630] The lateral extent over which the second resilient region 238 contacts the outer wall 288 at the lip superior wall portion 268 and, optionally laterally outwardly of the lip superior wall portion 268, has the effect of spreading the compressive force on the patient's face exerted by the seal member 218. That is, the spreading distributes a contact area of the second resilient region 238 over a larger area of the lip superior wall portion 268 and, optionally, the outer wall 288. This creates a larger contact point over which the force is spread. An alternative involves reducing the flexibility of the lip superior wall portion 268. However, this alternative is less desirable than spreading the compressive force as described above because this alternative affects patient comfort by providing a hard, localised contact point in the patient-contact surface 290. The second resilient region 238 directs forces applied to the lip superior wall portion 268 into the deformation panel 294 where the force is absorbed by the translation and / or deformation of the deformation panel 294. In doing so, the second resilient region 238 substantially retains the position of the the flow directors 246 relative to the nare opening 222. Another way of understanding the effect of the second resilient region 238 is to understand that it braces the flow directors 246 in position relative to the lip superior wall portion 268. This enables a patient treatment to continue with little interference to the flow of respiratory gas (a) through the flow directors 246, (b) through the nare opening 222, and (c) through the second chamber 228, when deformation forces are applied to the patient contacting surface 290 of the outer wall 288.

[0631] Anatomical dead-space flushing is believed to occur in two ways. One way applies when the mouth is shut and the other way applies when the mouth is open.

[0632] In the case of the latter, flushing of the mouth and upper throat occurs towards the end of the exhalation cycle when the pressure within the mouth and throat of the patient drops below the elevated pressure of the respiratory gas supplied to the first chamber 226. At this point, respiratory gas enters the patient's mouth from the first chamber 226 via the oral opening 220. The respiratory gas travels to the back of the patient's mouth, then flows into the patient's nasal cavity, then exits through the nares and enters the second chamber 228 via the nare opening 222. This flow through the mouth and the nasal cavity flushes the patient's nasal cavity, mouth and upper throat with fresh respiratory gas. This flushing replaces the respiratory gas in those spaces (which has a high loading of carbon dioxide) with fresh respiratory gas. The fresh respiratory gas may have the same carbon dioxide loading as ambient air or may have a higher loading of oxygen than ambient air depending in the source of respiratory gas supplied to the patient interface. At inhalation, this fresh respiratory gas is at the front of the tidal inflow to the patient's lungs.

[0633] During most of the exhalation phase when the mouth is closed, the respiratory gas cannot enter the nares due to the gas pressure within the patient's nares being higher than the elevated gas pressure of the respiratory gas supplied via the patient interface 10. However, toward the end of the exhalation phase, when the gas pressure within the nasal cavity drops below the gas pressure of the supplied respiratory gas, or when the velocity of the gas exiting the flow directors 246 overcomes the flow of gas exiting the nares, the accelerated stream of respiratory gas from the flow directors 246 penetrates the nares so that anatomical dead-space in the nasal cavity and upper throat are flushed with fresh respiratory gas.

[0634] The dead space flushing described above replaces low oxygen -con tent respiratory gas in the patient's anatomical dead spaces with higher oxygen-content respiratory gas that is taken into the lungs at the start of the next inhalation cycle. The low oxygen-content respiratory gas is pushed out of the dead spaces and into the second chamber 228 where it exits the patient interface 10 via the bias flow holes 226 or other outlet. Flushing of the low oxygen-content (or said another way, high CO2 content) respiratory gas into the patient interface 10 means that the low oxygen-content respiratory gas is not available for inhalation at the start of the next breathing cycle. This is enabled in part by having the pressurised respiratory gas being supplied to the first chamber 226 in combination with the bias vent holes 216 or other outlet being located in the second chamber 228 such that there is a constant one-way flow through the patient interface 10 during at least the exhalation phase which removes low oxygen-content respiratory gas from the patient interface 10 by pushing it out of second chamber 228 via the bias holes 226.

[0635] Said another way, the dead space flushing described above replaces high carbon dioxide-content respiratory gas in the patient's anatomical dead space with lower carbon dioxide-content respiratory gas that is taken into the lungs at the start of the next inhalation cycle. The high carbon dioxide-content respiratory gas is pushed out of the anatomical dead space and into the second chamber 228 where it exits the patient interface 10 via the bias flow holes 226. Flushing of the high carbon dioxide-content respiratory gas into the patient interface 10 means that the high carbon dioxide-content respiratory gas is not available for inhalation at the start of the next breathing cycle.

[0636] Whilst providing a patient with supplemental oxygen would increase oxygen concentrations, it doesn't necessarily reduce CO2 levels present in the anatomical dead space as much as flushing the anatomical dead space with ambient air does. It follows that an advantage of this approach is that improved outcomes may be achieved without the need for supplemental oxygen in the respiratory gas that is supplied to the patient interface 10. This is particularly advantageous where there are shortages of supplemental oxygen. Furthermore, because removing the high carbon dioxide-content respiratory gas from a patient's anatomical dead-space may improve gas exchange within the lungs, it follows that this approach may provide improved outcomes that cannot be achieved with supplemental oxygen solely. Supplemental oxygen may be supplied to the patient interface 10 as part of the respiratory gas so that the respiratory gas has a higher oxygen content than ambient air. However, it is believed that respiratory gas having a higher oxygen content than ambient air isn't essential for achieving improved outcomes.

[0637] Alternative embodiments of the cushion module 20 are described below. They function in the same way as described above for the cushion module 20 in terms of delivering respiratory gas to a patient, removing excess respiratory gas and removing exhaled respiratory gas.

[0638] The embodiment described above involves supplying respiratory gas from a gas source to the first chamber 226 and venting respiratory gas from at least the second chamber 228. This configuration of supply and venting of respiratory gas involves the flow of respiratory gas from the first chamber 226 to the second chamber 228. In alternative embodiments, however, the housing 202 may be reconfigured to receive the supply of respiratory gas from a gas source into the second chamber 228 and to vent the respiratory gas from the first chamber 226. This configuration involves the flow of respiratory gas from the second chamber 228 to the first chamber 226 via the flow directors 246. In this configuration, with the mouth closed, the respiratory gas would flow from the second chamber 228 into the nares, thereby flushing the nasal cavity and upper throat. This flow is caused by a higher gas pressure in the second cavity than the gas pressure in the nasal cavity. The flow directors 246 in this arrangement limit the gas flow into the first chamber 226 so that the gas pressure is higher in the second chamber 228 and there is turbulence associated with the gas trying to flow into the flow directors 246. This turbulence causes some dead-space flushing in the nasal cavity.

[0639] When the mouth is open, the respiratory gas would flow from the second chamber 228 into the nasal cavity and then into the mouth via the upper throat. The respiratory gas would then exit through the mouth into the first chamber 226 and then exit the patient interface via the bias vent holes 216 or another outlet configuration.

[0640] While the embodiments of the cushion module described below are in the context of gas flow from the first chamber 226 to the second chamber 228, the same alternative gas flow applies to those embodiments, including variations of those embodiments, described below. That is, those cushion module embodiments described below may be utilized with the direction of the gas flow from the first chamber 226 to the second chamber 228 or from the second chamber 228 to the first chamber 226. Although the description of the seal member 218 above is in the context of the features being formed integrally by a moulding process, any one or more of the features may be formed separately and then assembled with the seal member 218. For example, the rearward panel 234 may be formed with an opening that is adapted to receive a preformed flow director unit which includes two spaced part flow directors 246 and a second resilient region 238. One reason for adopting this assembly method may be to form certain features from different materials. Referring to the flow director unit example, the unit may be formed of hard plastics material which has a considerably higher resistance to deformation than the same structure when formed of silicone.

[0641] The seal member 1218 shown in Figures 17 and 18 is the same as the seal member 218 in Figures 1 to 16 except for alternative forms of a deformation panel 1294, a first resilient region 1236 and a second resilient region 1238. For convenience, the features of the seal member 1218 in Figures 17 and 18 which are the same as the features of the seal member 218 shown in Figures 1 to 16 are denoted by the same reference number with a prefix "1" and the description above regarding Figures 1 to 16 applies equally to those same features which are shown in Figures 17 and 18 with the same base reference numeral, i.e. without the prefix. For example, the description above regarding the outer wall 288 of the seal member 218 applies equally to the outer wall 1288 of the seal member 1218.

[0642] The first resilient region 1236 is at a level that is lower than a level of the second resilient region 1238 having regard to a generally upright orientation of the patient interface. This is evident from a link between the first resilient region 1236 and the deformation panel 1294 being at a level that is lower than the level than a link between the second resilient region 1238 and the deformation panel 294. The second chamber surface 1272 of the first resilient region 1236 is inclined upwardly, having regard to an upright orientation of the patient interface 10, from the link between the first resilient region 1236 and the deformation panel 1294. This means that at least part of the first resilient region 1236 meets the outer wall 1288 at a position that is at a higher level, having regard to an upright orientation of the patient interface than the level where a corresponding part of the first resilient region 1236 in the proximal-distal direction meets the deformation panel 1294.

[0643] The first resilient region 1236 additionally differs from the first resilient region 236 in that the first resilient region 1236 decreases in wall thickness in the proximal direction from the connection with the outer wall 1288 to the connection with the deformation panel 1294. However, in other embodiments, only part of the first resilient region 1236 may decrease in wall thickness in the proximal direction. For example, a portion of the first resilient region 1236 extending proximally of the lower rim portion 1910 of the second distal opening 1906 may decrease in wall thickness in the proximal direction. The first resilient region 1236 includes a second chamber surface 1272 exposed to the second chamber 1228 (Figure 18). At least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the second chamber surface 1272 is inclined at an obtuse angle relative to the second chamber surface 1298 of the deformation panel 294 at a location where they meet (Figure 18). As shown in Figure 18, the first resilient region 1236 is inclined upwardly, having regard to an upright orientation of the patient interface 10, from the deformation panel 1294 to the outer wall 1288. This is manifested in at least part of the second chamber surface 1272 of the first resilient region 1236 being inclined in the upwardly direction from the outer wall 1288 to the deformation panel 1294. That inclined part of the first resilient region 1236 includes the central region 1240. The second resilient region 1238 is inclined in the upwardly from the deformation panel 1294 toward the lip superior wall portion 268, having regard to an upright orientation of the patient interface. This is the same general orientation for the second resilient region 238 shown in Figures 1 to 16.

[0644] The relative inclination of the first and second resilient regions 1236 and 1238 affects the level at which the first resilient region 1236 meets the deformation panel 1294. In the seal member 218 shown in Figure 17, at least at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10, the deformation panel 1294 meets the second chamber surface 1272 of the first resilient region 1236 below the level of an upper-most portion 1990 of the oral opening 1220. However, the geometry may change in other embodiments of the seal member 1218 such that, at least at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10, the deformation panel 1294 may meet the second chamber surface 1272 of the first resilient region 1236 at a location at or above the level of an upper-most portion 1990 of the oral opening 220.

[0645] As with the deformation panel 294 of Figure 10, the deformation panel 1294 of Figure 18 includes a first wall 1264, the bend 1928 and a second wall 1266. However, the first wall 1264 includes a straight section 1926 and a curved segment 1930 linking the straight section 1926 with the first resilient region 1236. The first resilient region 1236 includes a first chamber surface 1270 that is exposed to the first chamber 1226. The curvature of at least part of the first chamber surface 1270 of the first resilient region 1236 is contiguous with the curvature of the curved segment 1930.

[0646] The second wall 1266 separates the second resilient region 1294 from the bend 1928. The second wall 1266 has a wall thickness that is less than the wall thickness of the second resilient region 1238. The deformation panel 1294 has an inverted L-shaped cross-section in the resting position, shown in Figure 18, at a vertical mid-plane through the patient interface 10 in the proximal-distal direction. The first wall 1264 projects from the first resilient region 1236, the second wall 1266 projects from the rearward panel 234. Both the first wall 1264 and the second wall 1266 join with respective opposite sides of the bend 1928.

[0647] Deformation of the deformation panel 1294 occurs in two stages. The second resilient region 1238, the transition portion 1916 and the lateral portions 800 (which form the rearward panel 1234) are relatively resistant to deformation compared to the first and second walls 1264, 1266. Accordingly, the deformation panel 1294 will deform more readily than the second wall 1266. The first stage of deformation involves a force being applied to the patient-contact surface 290 such that the second resilient region 1238 is displaced toward the first resilient region 1236. This causes the first wall 1264 to fold about its line of connection with the first resilient region 1236. In the second stage of deformation, as the second resilient region 1238 continues to be displaced towards the first resilient region 1236, the bend 1928 translates toward the second resilient region 1238 so the first wall 1264 lengthens and the second wall 1266 shortens. This translating motion is the "rolling" described above with reference to Figures 59A to 59D and their associated description in international patent application PCT / NZ2020 / 050072.

[0648] The curved segment 1930 adds to the dimension of the deformation panel 1294 in the vertical direction. In other words, the dimension of the deformation panel 1294 in the vertical direction, at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10, is more than half of the dimension of the lip superior wall portion 1268 in the vertical direction, at a vertical mid-plane through the patient interface in the proximal- distal direction, having regard to an upright orientation of the patient interface. In alternative embodiments, using the dimensions at the same vertical mid-plane along the line A-A in Figures 1 and 7 for comparison, the dimension of the deformation panel 1294 in the vertical direction may be more than three-quarters of the dimension of the lip superior wall portion 1268 in the vertical direction, may be more than the dimension of the lip superior wall portion 268 in the vertical direction, may be in the range of 80 to 120% of the dimension of the lip superior wall portion 268 in the vertical direction or may be more than the vertical spacing between the upper and lower rim portions 1908, 1910 of the second distal opening 1906 in the vertical direction.

[0649] The seal member 2218 shown in Figures 19 and 22 is the same as the seal member 218 in Figures 1 to 16 except an alternative dividing wall 2230. For convenience, the features of the seal member 2218 in Figures 19 to 22 which are the same as the features of the seal member 218 shown in Figures 1 to 16 are denoted by the same reference number with a prefix of "2" and the description above regarding Figures 1 to 16 applies equally to those same features which are shown in Figures 19 to 22 with the same base reference numeral, i.e. without the prefix. For example, the description above regarding the outer wall 288 of the seal member 218 applies equally to the outer wall 2288 of the seal member 2218.

[0650] The dividing wall 2230 includes the forward panel 2232, the deformation panel 2294 and the rearward panel. The forward panel 2232 includes the first resilient region 2236. The rearward panel 2234 includes the second resilient region 2238. The second resilient region includes flow directors 2246. The flow directors 2246 are provided on the second resilient region 2264 as a gas flow passage 2296 through the second resilient region 2238. The flow directors 2246 include a rim 2254. The rim 2254 defines the second opening 2252. As shown in Figure 20, the second resilient region 2238 includes two flow directors 2246, but in alternative forms, the second resilient region 2238 may include only one flow director 2246, more than two flow directors 2246, or no flow directors. In this embodiment, the second resilient region comprises a thickened rib extending laterally away from either side of the one or more flow directors 2246. The thickened rib may project into the first chamber 2226 and into the second chamber 2228 from the rearward panel 2234.

[0651] The first resilient region 2236 is similar to the first resilient region 1236 in Figures 17 and 18 in the central region 2240. That is, the first resilient region 2236 meets the outer wall 2288 along the lower rim portion 2910 and, immediately laterally outwardly from the second distal opening 2906, the first resilient region 2236 meets the outer wall 2288 along a line that is adjacent to the first rim 2904 of the first distal opening 2902. Lateral regions 2242 of the first resilient region 2236 extend from the central region to the lateral extent of the deformation panel 2294. In other words, the lateral regions 2242 of the first resilient region 2236 extend laterally of the second distal opening 2906. However, laterally outwardly of the first distal opening 902, the lateral regions 2242 of the first resilient region 2236 are inclined downwardly in the laterally outward direction, having regard to an upright orientation of the patient interface. The lateral regions 2242 extend below the level of the first opening 2250 of the flow directors 2246. In other words, the first resilient region 2236 meets the outer wall 2288 along a contour that at least partly follows the first rim 2904 of the first distal opening 2902. Also, the first resilient region 2236 meets the outer wall 2288 at least partly along a contour that follows the lower rim 2910 of the second distal opening 2906. These lateral regions 2242 have a generally uniform wall thickness. However, in other embodiments, the wall thickness of the lateral regions 2242 may vary.

[0652] The lateral portions 800 of the rearward panel 2234 extend laterally beyond the first resilient region 2236. At those lateral locations, at least part of the dividing wall 2230 meets the outer wall 2288 at a level that is below the level of the lip superior wall portion 2268. Furthermore, the level is below the level of the first resilient region 2236 at a vertical mid-plane in the proximal-distal direction, having regard to an upright orientation of the patient interface. The part of the dividing wall 2230 that meets the outer wall at that level may include part of the first resilient region 2236. The part of the dividing wall 2230 that meets the outer wall at that level may include part of the rearward panel 2234. As shown in Figure 19, the lateral portions 800 that are laterally beyond the deformation panel 2294 meet the outer wall 2288 at a level that is below a level that is half-way between the upper-most portion 2990 to the lower-most portion 2992 of the oral opening 2220 in the vertical direction, having regard to an upright orientation of the patient interface.

[0653] The relatively low level of the laterally outer sides of the dividing wall 2230 compared to the laterally outer sides of the dividing wall 230 is due to the dividing wall 2230 being curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction. In the embodiment shown in Figures 19 to 22, the dividing wall 2230 forms an arc when viewed from the first distal opening 2902. The dividing wall 2230 is curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction from the flow directors 2246.

[0654] Alternatively, the dividing wall 2230 may be curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction from the first resilient region 2236. In a further alternative, the dividing wall 2230 may be curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction from the second resilient region 2238. In a further alternative, the dividing wall 2230 may be curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction from the lateral edges of the second distal opening 2906. In a further alternative, the dividing wall 2230 may be curved downwardly, having regard to an upright orientation of the patient interface 10, in a laterally outward direction from a vertical mid-plane in the proximal-distal direction through the patient interface 10.

[0655] In further alternatives, one or more of the forward panel 2232, the rearward panel 2234 and the deformation panel 2294 may be curved downwardly. That is, in the lateral direction, the forward panel 2232 may be curved downwardly from a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10. Additionally or alternatively, in the lateral direction, the rearward panel may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface 10. Additionally or alternatively, in the lateral direction, the deformation panel 2294 may be curved downwardly from a vertical midplane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10. For example, in one embodiment, in the lateral direction, the rearward panel 2234 and the deformation panel 2294 may be curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface 10. Optionally in this embodiment, the second resilient region 2238 may comprise the thickened rib extending laterally away from either side of the one or more flow directors 2246. The thickened rib may project into the first chamber 2226 and into the second chamber 2228 from the rearward panel 2234.

[0656] An alternative seal member 3218 shown in Figures 23 to 40. Some of the features of the seal member 3218 are the same as the features of seal member 218 in Figures 1 to 16. Those features which are the same as the features of the seal member 218 shown in Figures 1 to 16 are denoted by the same reference number with a prefix of "3" and the description above regarding Figures 1 to 16 applies equally to those same features which are shown in Figures 23 to 40 with the same base reference numeral, i.e. without the prefix. For example, the description above regarding the outer wall 288 of the seal member 218 applies equally to the outer wall 3288 of the seal member 3218.

[0657] Furthermore, the seal member 3218 includes a first resilient region 3236, second resilient region 3238, flow directors 3246 and lateral portions 3800 which are similar to the corresponding features in the seal member 218 shown in Figures 19 to 22. The deformation panel 3294 extends laterally across the dividing wall 3230 (Figure 26). However, lateral ends 936 of the deformation panel 3294 are spaced from the outer wall 3288. The first resilient region 3236 also extends laterally across the dividing wall 3230. The first resilient region 3236 extends laterally beyond the lateral ends 936 of the deformation panel 3294. As shown in Figure 28, the first resilient region 3236 sweeps in the proximal direction about the lateral ends 936 of the second resilient region 3238. In the laterally outward direction, part of the first resilient region 3236 is between the second resilient region and the outer wall 3288. However, in that lateral direction, the first resilient region 3236 is spaced from the second resilient region 3238 by part of the rearward panel 3234.

[0658] The dividing wall 3230 is curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction. In the embodiment shown in Figures 26 to 28, the dividing wall 3230 forms an arc when viewed from the first distal opening 2902. The dividing wall 3230 is curved downwardly, having regard to a generally upright orientation of the patient interface 10, in a laterally outward direction from a vertical mid-plane in the proximal-distal direction through the patient interface 10.

[0659] With reference to the deformation panel 3294, the second resilient region 3238 extends laterally to a level that is below the level of the deformation panel 3294 at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10. In particular, second resilient region 3238 extends laterally to a level that is below the level of a lower rim portion 3910 of the second distal opening 3906 at a laterally-outermost location of the lower rim portion 3910, having regard to an upright orientation of the patient interface.

[0660] The second resilient region 3238 extends laterally across the dividing wall 3230. The second resilient region 3238 extends laterally beyond the one or more oral openings 3220. Furthermore, the second resilient region 3238 is spaced from the deformation panel 3294. However, the second resilient region 3238 and the deformation panel 3294 converge toward each other in the lateral direction. The lateral orientation of the second resilient region 3238 is shown in Figures 26 and 27. The deformation panel 3294 includes a first wall 3264 and a bend 3928 (Figure 28). The first resilient region 3236 meets the first wall 3264 and the rearward panel 3234 meets the bend 3928. A line where the first resilient region 3236 meets the first wall 3264 is at a lower level in the vertical direction than a line where the rearward panel 3234 meets the bend 3928. The second resilient region 3238 diverges from the patient-contact surface 3290 of the outer wall 3288 in the lateral direction. The lateral portions 3800 of the rearward panel 3234 include first and second surfaces 3942, 3944 which respectively are exposed to the first chamber 3226 and second chamber 3228. The second resilient region 3238 projects away from the first chamber surface 3276 into the first chamber 226. Additionally, the second resilient region 3238 projects into the second chamber 228. The second resilient region 3238 comprises an arcuate band that extends laterally across the rearward panel 3234. The second resilient region 3238 extends laterally outwardly and downwardly generally following the curvature of the rearward panel 3234. The second resilient region 3238 decreases in wall thickness, in the lateral direction, in terms of the extent to which the second resilient region 3238 projects from the second chamber surface 3278 into the second chamber 228. Alternatively, the second resilient region 3238 may decrease in wall thickness, in the lateral direction, in terms of the extent to which the second resilient region 3238 projects into the first chamber 226. Furthermore, the width of the second resilient region 3238 in the proximal-distal direction may taper from the flow directors 3246 in the lateral direction. The taper may be on a side of the second resilient region 3238 that projects into the first chamber 3226.

[0661] In the seal member 3218, the lateral sides 800 of the dividing wall 3230 extend to a level that is lower, having regard to an upright orientation of the patient interface 10, seal member 3218 than a level half-way between the upper-most portion 3990 and lower-most portion 3992 of the oral opening 3220. In an alternative form, the lateral portions 3800 of the dividing wall 3230 extend to a level that is between the level of the upper-most portion 3990 of the oral opening and a level half-way between the uppermost portion 3990 and lower-most portion 3992 of the oral opening 3220, having regard to an upright orientation of the patient interface 10.

[0662] The lateral orientation of the second resilient region 3238 is generally orthogonal to deformation forces applied through the lip superior wall portion 3268. The downward curvature of the second resilient region 3238 and the positioning of the first resilient region 3236 between the second resilient region 3238 and the outer wall 3288 causes the dividing wall to pivot about the lateral ends 936 when a force is applied through patient contact portion 3290. While the deformation panel 3294 deforms in the same way as in previous embodiments, the pivoting of the rearward panel 3234 about the lateral ends 936 of the second resilient region 3238 provides a rolling motion of the rearward panel 3234 relative to the forward panel 3232. Given that the second resilient region 3238 is above the first resilient region 3236, having regard to an upright orientation of the patient interface 10 along a vertical mid-plane in the proximal-distal direction, the second resilient region 3238 translates over the top of the first resilient region 3236. In contrast, in the embodiments shown in Figures 1 to 18, the rearward panel 3234 translates as a single body in the proximal-distal direction relative to the first resilient region 3236. The rolling motion enables a greater range of relative positions between the first resilient region 3236 and the second resilient region 3238 compared to the embodiments shown in Figures 1 to 18. The greater range enables the dividing wall to accommodate greater displacements of the second resilient region 3238 relative to the first resilient region 3236 due to deformation forces applied to the patient contact portion 3290.

[0663] The orientation of the second resilient region 3238 relative to the first resilient region 3236 results in the spacing between them diminishing in the lateral direction. The greatest freedom of movement, therefore, is in the central region where the lengths of the first wall 3264 and the second wall 3266 are the greatest. This configuration contributes to causing the rolling motion of the second resilient region 3238 about the lateral ends 936 relative to the first resilient region. However, this configuration also results in a more controlled deformation of the deformation panel 3294 and a smoother rolling motion.

[0664] The downward curvature of the rearward panel 3234 and the second resilient region 3238 resists inversion of the rearward panel 3234 under the influence of a deformation force applied to the patient contact surface 3290. The close positioning of the lateral ends 936 to the first resilient region 3236 anchor the second resilient region 3238 so that it behaves like an arch when a downward force is applied to upper parts of the arch. The wall thickness of the second resilient region 3238 contributes to resisting inversion. Additionally, the anchoring of the lateral ends 936 directs downward forces on the second resilient region 3238 into the adjacent parts of the first resilient region 3236 such that downward forces, and therefore inversion, are resisted.

[0665] The flow directors 3246 are integrated with the second resilient region 3238. The flow directors 3246 include a block 3932 projecting from the second resilient region 3238. Each flow director 3246 includes a rim 3254 projecting from the block 3932. The block 3932 includes inclined sides 3934 extending from the rims 3254. The inclined sides 3934 extend from the rims 3254 to the second resilient region 3238 on the laterally outer side of the rims 3254. The inclined sides 3934 extend from the rims 3254 to the second resilient region 3238 on the distal side of the block 3932. In an alternative embodiment, however, the inclined wall 936 may extend to the deformation panel 3294. On the proximal side of the block 3932, the inclined side 3934 extends to the lip superior wall portion 3268. However, in an alternative embodiment, the inclined side 3934 on the proximal side of the block 3932 may extend to the second resilient region 3238 and may be spaced from the lip superior wall portion 268.

[0666] Although the second resilient region 3238 includes two flow directors 3246, alternative embodiments of the second resilient region 3238 may include only one flow director 4246, more than two flow directors 3246 or no flow directors. In alternative embodiments, the or each flow director 3246 comprises a channel through the second resilient region 3238. Outlets of the flow directors 3246 which open into the second chamber 3228 may be flush with the surface of the second resilient region 3238 that is exposed to the second chamber 3228. Inlets of the flow directors 3246 which open into the first chamber 3226 may be flush with the surface of the second resilient region 3238 that is exposed to the first chamber 3226.

[0667] The inclined side 936 extends between laterally inner sides of the flow directors 3246 for form a saddle-shaped spacer 260. The spacer 260 is an integral part of the block 3932. The function of the second resilient region 3238 may be assisted by the spacer 3260 (Figures 23 and 31). The spacer 3260 connects both flow directors 3246. The spacer 3260 extends part way up each flow director 3246. Connection of the spacer 260 to the flow director 3246 reinforces the flow director 3246 and makes it more resilient to deformation. The connection of the spacer 3260 to the flow director 3246 also reduces the likelihood of the flow director 3246 buckling inwardly or outwardly.

[0668] Reducing the likelihood of buckling assists to retain the alignment of the flow directors 3246 in a direction that, in use, directs a flow of respiratory gas toward the nare opening 3222. In alternative embodiments the function and structure of the block 3932 and spacer 3260 may instead be incorporated into a unitary second resilient region 3238.

[0669] A proximal side of the second resilient region 3238 projecting into the first chamber 3226 includes a recess 3994 as part of the first opening 3250 of a flow director 3246. However, the distal side of the second resilient region 3238 projecting into the first chamber 3226 may alternatively or may also include the recess 3994 as part of the first opening 3250 of a flow director 3246. In an alternative embodiment, the second resilient region 3238 may define the entire first opening 3250 of the flow directors 3246 and still be spaced from the outer wall 3288 in the same way as described above. While each of the seal members 230, 1230, 2230 and 3230 described above can be used with the same housing 202, frame 30 and conduit connector 40 shown in Figures 1 to 3, the cushion module 320 utilises an alternative housing arrangement. The outer wall 3288 of the cushion module 320 includes a first housing 948 associated with the first chamber 3226. That is, the first housing 948 forms part of the outer wall 3288 associated with the first chamber 3226. The outer wall 3288 of the cushion module 320 also includes a separate second housing 950 associated with the second chamber 3228. That is, the second housing 950 forms part of the outer wall 3288 associated with the second chamber 3228. The first housing 948 is spaced from the second housing 950. The seal member 3230 is adapted to accommodate the first and second housings 948, 950 in separate openings associated with the first and second chambers 3226, 3228. That is, the first housing 948 is associated with the first distal opening 3902 and the second housing is associated with the second distal opening 3906. Furthermore, part of the seal member 3230 is between the first housing 948 and the second housing 950.

[0670] The first resilient region 3236 extends in the proximal direction from a part of the seal member 3218 that is between the first opening 3902 and the second opening 3906. The part of the seal member 3218 that is between the first opening 3902 and the second opening 3906 is a transom which is part of the outer wall 3288.

[0671] The first resilient region 3236 extends in the proximal direction from at least part of the transom. Accordingly, part of the first resilient region 3236 follows the contour of the lower rim portion 3910. The lower rim portion 3910 is curved downwardly in the lateral direction from a vertical mid-plane in the proximal-distal direction through the patient interface 10, having regard to an upright orientation of the patient interface 10. The inclination results in at least part of the second chamber surface 3272 of the first resilient region 3236, at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10, being at or above the level of the upper-most portion 3990 of the one or more oral opening 3220. In an alternative embodiment, however, at least part of the second chamber surface 3272 of the first resilient region 3236 at a vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to an upright orientation of the patient interface 10, may be below the level of the upper-most portion 3990 of the oral opening 3220 and may be above a sleeve 3212 in the first housing 948.

[0672] Having regard to Figure 23, it can be seen that the lateral dimension of the second housing 950 is greater than the lateral dimension of the first housing 948. However, in alternative embodiments, the lateral dimension of the second housing 950 may be the same as or less than the lateral dimension of the first housing 948. For example, the second housing 950 may include a lateral dimension that is in the range of 90% to 110% of the lateral dimension of the first housing 948. Compared to the oral opening 3220, the first housing 948 has a lateral width that is greater than the lateral width of the oral opening 3220. The second housing 950 is smaller than the first housing 948. The second housing is less than 75%, less than 50%, less than 40% or less than 30% of the size of the first housing 948. The second distal opening 3906 is smaller than the first distal opening 3902. The second distal opening 3906 is less than 75%, less than 50%, less than 40% or less than 30% of the area of the first distal opening 3902.

[0673] As with the housing 202, the first housing 948 (Figures 23, 32 and 37 to 39) includes a sleeve 3212 that is sized and shaped to connect with the frame 30. The sleeve 3212 forms an inlet opening 3292 through which respiratory gas can be communicated from the conduit connector 40 to the interior of the cushion module 320. The sleeve 3212 includes key formations 3214 that interact with the frame 30 to ensure correct alignment of the frame 30 with the first housing 948 when they are fitted together. In the cushion module 320, the first housing 948 is integrally formed with the seal member 3218. In this particular embodiment, the seal member 3218 is permanently joined to the first housing 948 by over-moulding. This is achieved in the same way that the housing 202 is integrally formed with the cushion module 20. In particular, the first housing 948 includes a series of tabs 3204 which project outwardly around its perimeter. The outer ends of the tabs 3204 are linked to a bead 3206 which runs continuously across all of the tabs 3204, thereby forming a series of discrete outer over-mould windows 3208 between the tabs 3204 and the bead 3206. The seal member 3218 is integrally formed with the first housing 948 by over-moulding a resilient material onto the first housing 948 to fill the outer over-mould of windows 3216. Therefore, the tabs 3204 and the bead 3206 become embedded in the resilient material and are mechanically interlocked with the seal member 3218. In other embodiments, the seal member 3218 may be permanently joined to the first housing by adhering or welding.

[0674] Furthermore, the first housing 948 includes an upper portion 954, above a notional laterally extending line (between the arrows marked 958 in Figure 37) between the laterally outer-most parts of the first housing 948. The first housing 948 further includes a basal portion 956. The basal portion 956 is a lower portion of the first housing 948 below the notional laterally extending line between the laterally outer-most parts of the first housing 948. The perimeter of the upper portion 954 has a radius of curvature that is less than the radius of curvature of the perimeter of the basal portion 956. At least part of the curvature of the upper portion 954 follows the first resilient region 4264 along the outer wall 288. In an alternative embodiment, the first housing may be symmetrical about the notional laterally extending line between the laterally outer-most parts of the first housing 948.

[0675] The second housing 950 may be removably or permanently joined to the seal member 3218. For example, the second housing 950 may be adhered, welded, glued or mechanically fastened to the seal member 3218. Either way, the connection of the second housing 950 to the seal member 3218 may be permanent or releasable.

[0676] Alternatively, the second housing 950 may be integrated with the seal member 3218 by an over-mould procedure that is separate from the over-mould procedure for integrating the first housing 948 with the seal member 3218. In such an example a material would be over-moulded over both the seal member 3218 and the second housing 950.

[0677] In the cushion module 320 shown in Figures 31 to 47, the second housing 950 includes two components that join to one another. In this embodiment, the second housing 950 is snap-fitted to the seal member 3218. In this regard, the second housing 950 is cooperable with the upper rim portion 908 and the lower rim portion 910 of the second distal opening 906 to from a seal between the second housing 950 and the second distal opening 906. This is achieved by the second housing 950 and the upper rim portion 908 and the lower rim portion 910 of the second distal opening 906 including co-operable seal-forming formations. In this embodiment, the second housing 950 includes an outlet panel outlet and a fastening bracket 962 which are co-operable to form a seal between the second housing 950 and the second distal opening 906.

[0678] The outlet panel 960 is formed to enable respiratory gas to flow through it from the second chamber 3228 to externally of the cushion module 320. That is, the outlet panel 960 includes one or more outlets 3996 for respiratory gas. In one embodiment, the outlets 3996 are a bias vent. In another embodiment, the outlet 3996 is a single opening configured to convey respiratory gas to an exhaust conduit. The exhaust conduit may be one conduit of a dual-limb patient interface. In an alternative embodiment, the outlet 3996 is in fluid communication with a filter. In one embodiment a separate inlet conduit of the dual-limb patient interface connects with the first housing 948 to deliver respiratory gas from a source to the first chamber 3226. The second housing 950 also includes a fastening bracket 962 which is co-operable with the outlet panel 960 to secure the second housing 950 over the second distal opening 906. In the cushion module 320, the outlet panel 960 and the fastening bracket 962 are co-operable to seal against the upper rim portion 3908 and the lower rim portion 3910. In other words, the outlet panel 960 and the fastening bracket 962 snap-fit together to from a seal between the second housing 950 and the second distal opening 906. In this way, the respiratory gas is controlled to flow through the second housing 950 in order to be exhausted from the cushion module 320. In an embodiment, a filter or diffuser may be permanently or releasably connected to the second housing 950. The filter or diffuser may be in fluid communication with the outlet 3996.

[0679] The seal is achieved by the upper rim portion 3908 and the lower rim portion 3910 including a rim profile 964 that complements a seal formation on the fastening bracket 962. The rim profile 964 includes a flange 966 with a bead 968. The flange 966 includes a first side 970 from which the bead 968 projects. The flange 966 further includes a second side 972 opposite to the first side 970. The seal formation includes a bevel 974 about the perimeter of the fastening bracket 962 and which is shaped to contact the flange 966 and the bead 968. In particular, the bevel 974 includes a perimeter surface 976 and an adjacent contact surface 978. The seal is formed, in part, by bringing the fastening bracket 962 into contact with the rim profile 964 so that the flange 966 contacts the perimeter surface 976 and the bead 968 contacts the adjacent contact surface 978. The final step of forming the seal involves pressing the rim formation against the fastening bracket 962. To achieve this, the outlet panel 960 includes snap- fit fingers 980 and the fastening bracket 962 includes receiving formations that interact with the snap-fit fingers 980. The receiving formations may include any suitable formation for interacting with the snap-fit fingers 980 to compress the rim profile 964 between the outlet panel 960 and the fastening bracket 962. The snap-fit fingers include a stem 982 and a catch 984. In the fastening bracket 962, the formations include one or more windows 96 through which the snap-fit fingers 980 can pass and retention blocks which are adapted to sit in a space between the catch 984 and the surface of the window 986. The dimensions of the snap-fit fingers 980 are selected to cause the rim profile to be compressed between the outlet panel 960 and the fastening bracket 962.

[0680] While the embodiment described above involves a snap-fit connection between the outlet panel 960 and the fastening bracket 962, other forms of connection may be utilised provided they have the same effect of forming a seal between the second housing 950 and the seal member. For example, the outlet panel 960 and the fastening bracket 962 may be connectable by mechanical or magnetic formations or by formations that are a combination mechanical and magnetic interaction. Alternatively, the connection between the outlet panel 960 and the fastening bracket 962 may be an interference fit or they may be adhered or welded together.

[0681] In the embodiment described above, the second housing 950 is connected to the seal member 3218 by clamping the seal member 3218 between parts of the second housing 950. That is, the seal member 3218 is clamped between the outlet panel 960 and the fastening bracket 962. In another embodiment, the seal member 3218 is elastically stretched over a retaining feature of the second housing 950. The retaining feature may be a perimeter groove in which the elastically stretched upper and lower rims 3908, 3910 may be seated to form a seal.

[0682] In a further embodiment, the outlet panel 960 and the fastening bracket 962 may be configured to clamp the seal member 3218 between them without complementary formations on the outlet panel 960 and the fastening bracket 962 and on the upper rim portion 3908 and the lower rim portion 3910. In other words, the upper rim portion 3908 and the lower rim portion 3910 may not include the rim profile 964 and the outlet panel 960 and the fastening bracket 962 may not include a dedicated seal formation.

[0683] In a further embodiment, the second housing 950 may be adhered or welded to the seal member 3218. Such connection to the seal member 3218 avoids the need for the second housing 950 to have a dual-panel configuration that snap fits or otherwise connected together to clamp the seal member 3218 between the panels.

[0684] In an alternative embodiment, the second housing 950 may be removably joined to the first housing 948. While the second housing 950 of the embodiment shown in Figures 23 to 40 includes two components which are not integrated with the seal member 3218, a further alternative embodiment the seal member 2318 may be permanently joined or integrally formed with one component of the second housing 950 (by, for example, over-moulding, adhering or welding) and another component of the second housing 950 is configured to join to the permanently joined component. Furthermore, the components that form the second housing 950 may be removably joined to one another.

[0685] The flow directors 246, 1246, 2246 and 3246 described above have an elliptical profile in cross-section generally parallel to the plane of the dividing wall where the flow director 246, 1246, 2246 and 3246 is located. However alternative forms of the flow directors 246, 1246, 2246 and 3246 may include a circular or oval-shaped profile in cross-section generally parallel to the plane of the dividing wall 230, 1230, 2230, 3230 where the flow director 246, 1246, 2246 and 3246 is located. Furthermore, the flow directors 246, 1246, 2246 and 4246 may have a conical, tapering or stepped crosssection generally orthogonal to the dividing wall 230 where the flow director 246, 1246, 2246 and 3246 is located. In another alternative, the flow directors 246, 1246, 2246 and 3246 may have a uniform wall thickness. Examples of different shapes for the flow directors 246, 1246, 2246 and 3246 are disclosed in Figures 35, 41, 43, 45, 50, 56, 60 and 65A of international application PCT / NZ2022 / 050001 (published as WO2022 / 158987), in alternative views of those figures shown in the PCT application and in the description associated with those figures. The content of those figures and description is incorporated into this specification by this reference and should be read as single disclosure. These examples are not exhaustive of the different shapes and profiles that the flow directors 246, 1246, 2246 and 3246 may have.

[0686] While the flow directors 246, 1246, 2246 and 3246 are shown in pairs that are symmetrical about a vertical mid-plane through the patient interface 10 in the proximal- distal direction, having regard to a generally upright orientation of the patient interface 10, alternative forms of the flow directors may be asymmetrical. The flow directors 246, 1246, 2246 and 3246 may be asymmetrical in regard to location and shape. The shape asymmetry may include one flow director 246, 1246, 2246 and 3246 having a profile that is greater or less than the profile another flow director 246, 1246, 2246 and 3246 that is part of the patient interface 10. The profile is the cross-section generally parallel to the plane of the dividing wall where the flow director 246, 1246, 2246 and 4246 is located. In an embodiment, ratio of the cross-sectional areas of the flow directors may be in the range of greater than 1 : 1 to 1: 10. For example, one embodiment may comprise flow directors have a cross-sectional ratio of 1 :3.

[0687] References to location and alignment of the one or more flow directors 246, 1246, 2246 and 3246 include a reference to the location and alignment, respectively, of a mid-point in the lateral direction between the lateral-most edges of the second opening 252, 1252, 2252, 3252. In an alternative form, the patient interface may include only one flow director 246, 1246, 2246 and 3246. The one flow director 246, 1246, 2246 and 3246 may be centrally aligned on the vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to a generally upright orientation of the patient interface 10. In a further alternative, the one flow director 246, 1246, 2246 and 3246 may be off-set from the vertical mid-plane through the patient interface 10 in the proximal-distal direction, having regard to a generally upright orientation of the patient interface 10.

[0688] As mentioned previously, the patient interface 10 further includes the frame 30 and the conduit connector 40.

[0689] The frame 30 includes the central body portion 302 that includes one or more passages for conveying respiratory gas from a gas source to the cushion module 20, 120, 220, 230 and therefore to the patient. The frame 30 includes side wings 304 extending from the central body portion 302. Each side-wing 304 includes a pair of openings 308 are arrange to co-operate with headgear (such as resilient straps) for fitting the patient interface to a patient. The headgear operates by pulling the patient interface 10 into contact with the patient's face to form a substantially air-tight seal when respiratory gas at elevated gas pressure is delivered to the patient via the patient interface 10. One opening 308 on each side wing 304 includes a bar 306 for connecting with a headgear clip to allow for easier connection to and disconnection from headgear. The headgear may comprise 4-point headgear. That is, the headgear may comprise four straps which respectively connect with the bars 306 and with the openings 308 in the upper part of the frame 30.

[0690] While this embodiment includes the frame 30, the headgear connection points may be integrated with or connected to the housing 202, 1202, 2202, 948 or to the conduit connector 40 in alternative embodiments. If so, the frame 30 is not necessary and could be omitted from such embodiments.

[0691] The frame 30 further includes a connector sleeve 310 that includes four arcuate fingers 312. The connector sleeve 310 has an inner wall 314 which includes a concave profile having the shape of shape of a spherical segment. The outer wall 312 of the connector sleeve 310 is shaped to fit within the sleeve 212, 1212, 2212, 3212 of the housing 202, 1202, 2202, 948. The arcuate fingers 312 are spaced by detents which are shaped to fit with the key formations 214. The location of the key formations 214 and the detents ensures that the frame 30 aligns correctly with the housing 202, 1202, 2202, 948 when they are fitted together.

[0692] Each arcuate finger 316 has an end with an arcuate flange portion 318 which forms a snap-fit with a radially inwardly projecting lip 298 of the sleeve 212, 1212, 2212, 3212. The snap-fit holds the frame 30 to the housing 202. The snap-fit may be releasable or may be a permanent fit between the frame 30 and the housing 202, 1202, 2202, 948. Instead of a snap-fit, the frame 30 may be connected to the housing 202, 1202, 2202, 948 by any conventional means, such as gluing or welding. Such connection between the frame 30 and the housing 202, 1202, 2202, 948 may be permanent or may enable releasable connection of the frame 30 to the housing 202. Permanent connection may be provided by welding, in some embodiments.

[0693] Having regard to the comments above regarding variations on the general form shown in Figure 1, one such variation of the general form, and which is applicable to the aspects and embodiments described below, is where the housing 202 and the frame 30 are formed integrally. In other words, the patient interface 10 may include a unitary structure that performs the same function of the housing 202 and frame 30. While the housing 202 and the frame 30 are described as being separate components of the patient interface 10, the description should be read as including the option of an integrally formed component that functions in the same way as the housing 202 and frame 30.

[0694] The conduit connector 40 (Figure 2) includes an elbow 60 and a socket insert 50 which couples the elbow 60 to the frame 30. The conduit connector 40 further includes a swivel connector 80 which connects to a conduit that delivers respiratory gas from a flow source, such as a ventilator, a flow generator, a humidifier or a wall source. The swivel connector 80, elbow 60 and socket insert 50 form a flow path for respiratory gas into the cushion module 20, 120, 220, 230 from a conduit.

[0695] The socket insert 50 has an outer wall 502 that includes a convex spherical segment. The shape of the spherical segment fits with the shape of the concave spherical segment of the inner wall 314 of the frame 30. The outer wall 502 is joined at one end to an inner wall 504. The inner wall 504 includes an inner surface 506 that includes radially inwardly projecting shoulder 508. The socket insert 50 press fits with the frame 30 such that the outer wall 502 seats in the concave segment of the inner wall 314 of the frame 30 (Figure 4). This connection forms a ball and socket style connection which allows the socket to rotate within the spherical segment of the inner wall 314 of the frame 30.

[0696] The elbow 60 includes a first conduit portion 602 and a second conduit portion 608. Longitudinal axes of the first conduit portion 602 and the second conduit portion 608 are set at an oblique angle. Accordingly, respiratory gas flowing through the elbow 60 undergoes a change of direction from the first conduit portion 602 to the second conduit portion 608. The conduit portion 602 includes a radially projecting flange 606. The elbow 60 is connected to the socket insert 50 by snap fitting the flange 606 with the shoulder 508. In other embodiments, however, the elbow 60 may connected to the socket insert 50 by welding or by adhesive, in which case the shoulder 508 and the flange may be omitted.

[0697] The second conduit portion 608 includes an inlet 610 for respiratory gas. The inlet 610 is at the distal end of the second conduit portion 608. The second conduit portion 608 further includes a structure (see Figure 5) that co-operates with an anti-asphyxiation valve 70 (Figures 2, 4 and 5) to permit ambient air into the patient interface if the source of respiratory gas fails or the conduit for conveying the gas from the source to the patient interface 10 becomes obstructed. More specifically, the second conduit portion 608 includes an opening 612. The opening is in a lower portion of the second conduit portion 608. A spine 614 is disposed adjacent the opening 612 and supports a panel 616 that is spaced from the opening 612. The spacing of the panel from the opening creates a gap 618 through which ambient air can access the opening.

[0698] An alternative patient interface 4010 is shown in Figures 41 to 53. Some features of the patient interface 4010 are the same as the features of patient interface 10 in Figures 1 to 16. Features which are the same as the features of the patient interface 10 shown in Figures 1 to 16 are denoted by the same reference number with a prefix of "4" and the description above regarding Figures 1 to 16 applies equally to those same features which are shown in Figures 41 to 53 with the same base reference numeral, i.e. without the prefix. For example, the description above regarding the outer wall 288 of the seal member 218 applies equally to the outer wall 4288 of the seal member 4218. The outer wall 4288 of this alternative seal member 4218 includes some notable differences, namely the outer wall 4288 extends at least partially across the distal end of the first chamber 3266 towards the first distal opening 4902.

[0699] Having regard to Figures 41 to 53, an alternative patient interface 4010 comprises a cushion module 4020, a frame 4030 and a conduit connector 40. The conduit connector 40 comprises structural components for connecting the cushion module 4020 to a source of respiratory gas, such as a ventilator, humidifier, flow generator or wall source. In this embodiment, the conduit connector 40 is removably attached with the frame 4030. The removable attachment may take the form of a snap-fit connection, a bayonet fitting or mechanical fastening structure. In the current embodiment shown, the conduit connector 40 and frame 4030 comprise a rotator cuff that rotatably links the conduit connector 40 to the mask frame 4030 to form a flow path for respiratory gas from a conduit to the first chamber 3226 similar to that shown in Figure 4.

[0700] In this embodiment, the patient interface 4010 is in the form of a sub-nasal full-face mask where the cushion module 4020 comprises a seal member 4218 and a housing 4950. Collectively, the seal member 4218 and a housing 4950 form an outer wall 4288 of the cushion module 4020. The connection of the conduit connector 40 and the frame 4030 is the same as that disclosed in the embodiments of Figures 1 to 16.

[0701] The seal member 4218 comprises a dividing wall 4230. The dividing wall 4230 may have the configuration of any one of the dividing walls 230, 1320, 2230 and 3230 in terms of flow directors, first resilient region, second resilient region and deformation panel. The description above in respect of those dividing walls 230, 1320, 2230 and 3230 applies equally to this embodiment as if those dividing walls 230, 1320, 2230 and 3230 are optionally part of this seal member 4218.

[0702] The housing 4950, as shown in Figure 50 is formed of a substantially rigid plastics material. The plastics material provides structural support to the seal member 4218. In other embodiments, the housing 4950 may be formed of an elastomeric material. The elastomeric material may be reinforced. The reinforcement is sufficient to provide structural support to the seal member 4218. The reinforcement may be provided by regions of increased wall thickness or by inclusions formed of a relatively more rigid material. Additionally, the housing 4950 includes an outlet for exhausting gas from the second chamber 228. The outlet may include one or more openings for exhausting respiratory gas. For example, the outlet may comprise one or more openings for exhausting respiratory gas from the second chamber 228 to an exhaust gas conduit of a dual-limb patient interface. However, in this embodiment, the outlet includes a bias vent. The bias vent includes a group of bias vent holes 4216 through the housing 4950. The bias vent holes 4216, in this embodiment, facilitate the movement of exhaust respiratory gas to the ambient atmosphere.

[0703] In this embodiment, the housing 4950 maybe removably joined to the seal member 4218. In another embodiment, the connection of the housing 4950 to the seal member 3218 may be permanent, wherein the housing 4950 may be adhered, welded, glued or mechanically fastened to the seal member 4218. Another form of permanent connection can be achieved wherein the housing 4950 may be integrated with the seal member 4218 by an over-mould process. In such an embodiment, a material would be overmoulded over both the seal member 4218 and the housing 4950. This material may be the same material as the seal member 4218. In another embodiment, the seal member 4218 may be over-moulded with the housing 4950. In an alternative embodiment, the seal member 4218 may be overmoulded to the housing 4950, as described above in respect of the cushion module 20.

[0704] In the cushion module 4020 shown in Figures 41 to 53, the housing 4950 includes two components that attach to one another. One component is located within the seal member 4218 and the other component is located externally of the seal member 4218. The two components interact to compress the seal between them and form a substantially air-tight seal. The interaction between the two components may be permanent or releasable.

[0705] In this embodiment, the two components of the housing 4950 are an outlet panel 4951 and a fastening bracket 4955. They snap-fit together such that the seal member 4218 is clamped between them. In this regard, the housing 4950 is co-operable with seal member 4218 to form a substantially airtight seal between the housing 4950 and seal member 4218. This embodiment of the housing 4950 attachment is achieved through co-operable seal-forming formations on the housing 4950 and on a second rim 4964 which extends around the second distal opening 4906. In other embodiments, the housing 4950 may seal with the seal member 4218 without seal-forming formations or with alternative forms of seal-forming formations that position the seal member 4218 between the compnents for compression when the components interact. In this embodiment, the two components of the housing 4950 includes an outlet panel 4951 and a fastening bracket 4955 which are co-operable to form a substantially airtight seal between the housing 4950 and the seal member 4218. In this embodiment, the outlet panel 4951 and the fastening bracket 4955 snap-fit together to form a substantially airtight seal between the housing 4950 and the seal member 4218. In this way, respiratory gas is permitted to flow through the housing 4950 in order to be exhausted from the cushion module 4020.

[0706] The outlet panel 4951 includes an outlet panel protrusion 4952 that is co-operable with the seal member 4218. When the outlet panel 4952 is fitted to the seal member 4218, the outlet panel protrusion 4952 is adjacent to the second rim 4964. s The outlet panel protrusion 4952 extends around a periphery of the outlet panel 4951 on the proximal side of the outlet panel 4951 when attached to seal member 4218. The outlet panel protrusion 4952 extends around the at least one outlet 4216 in a proximal direction to the patient interface 4010. The outlet panel 4951 is enables respiratory gas to flow through it from the second chamber 3228 to externally of the cushion module 4020. That is, the outlet panel 4951 includes one or more outlets 4216 for respiratory gas. In one embodiment, the outlets 4216 are a bias vent. In another embodiment, the outlet 4216 is a single opening configured to convey respiratory gas to an exhaust conduit of a dual-limb patient interface.

[0707] A second recess 4953 circumscribes the second rim 4964 on the distal face of the seal member 4218. The second recess 4953 is adjacent the second rim 4964 such that the second rim is disposed between the second distal opening 4906 and the second recess 4953. The second recess 4953 describes a portion of the seal member 4218 on the outer wall 4288 which is recessed around a periphery of the second rim 4964.

[0708] The outlet panel protrusion 4952 is received by the second recess 4953 (Figure 52)when attached to the cushion module 4020 such that the outlet panel protrusion 4952 is positioned within the second recess 4953 of the seal member 4218. In this way, the second rim 4964 is compressed to create a seal between the second rim 4964 and the outlet panel protrusion 4952. In other words, the second recess 4953 formed by the seal member complements the outlet panel protrusion 4951.

[0709] The outlet panel 4951 includes at least one stem 4982. The at least one stem extends from a proximal face of the outlet panel 4951 through the second distal opening 4906 when the outlet panel 4951 is attached to the seal member 4218. The at least one stem 4982 includes a catch 4984 shaped to engage the fastening bracket 4955. The catch 4984 faces laterally outwardly of the outlet panel 4951. Preferably, the outlet panel 4951 includes at least two stems 4982 positioned on opposite sides of the proximal face of the outlet panel 4951. The at least two stems 4982 are positioned on either side of the at least one outlet 4216. The at least two stems 4982 may be positioned on laterally opposing sides of the outlet panel 4951. The at least two stems 4982 connect to the fastening bracket 4955 by resiliently deflecting inwardly such that the catch 4982 of each stem 4982 can pass through the second distal opening 4906 and the fastening bracket 4955. Once the at least two stems have passed through the fastening bracket 4955 and the second distal opening 4906, the at least two stems 4982 return substantially to their original position such that the catch 4982 engages the fastening bracket 4955 and creates a substantially secure attachment. The engagement between the fastening bracket 4955 and the outlet panel 4951 compresses the seal member 4218 between them. This contributes to forming the substantially airtight seal between the housing 4950 and the seal member 4218. In a variation that is not shown in the figures, the at least one stem 4982 may pass through an auxiliary hole in the seal member 4218 before connecting to the fastening bracket 4955. For example, auxiliary holes may be positioned in the second recess 4953 on opposing sides of the second distal opening 4906. The auxiliary holes may be sized to fit the at least one stem 4982 such that the auxiliary hole is slightly smaller in size than the at least one stem 4982 so that the seal member 4218 is stretched around the at least on stem 4982. This ensures that a substantially airtight seal is still maintained.. This variation ensures that gas flow characteristics through the second distal opening 4906 is unaffected by any obstructions caused by the at least one stem 4982.

[0710] In further variations, the connection between the at least one stem 4982 and the fastening bracket 4955 may be adhered, welded, or mechanically fastened to the outlet panel 4951 and the fastening bracket 4906. Or the at least one stem 4982 may be replaced with any alternative protrusion configured to interact with the fastening bracket 4955.

[0711] In another embodiment, the housing 4950 may be a singular component. The seal member 4218 may be pulled over or pushed into a cooperating portion of the housing 4950 to form a seal between the housing 4950 and the seal member 4218. For example, the housing 4950 may comprise a perimeter groove into which the second rim 4964 is seated. This may involve elastically stretching the second rim 4964 about the housing 4950 and allowing it to relax and seat within the groove. The second rim 4964 remains partly elastically stretched when seated in the groove so that the second rim 4964 grips the housing 4950. This creates a seal between the housing 4950 and the second rim 4964. This also contributes to retaining the housing 4950 connected with the seal member 4218 when respiratory therapy pressures are applied to the patient interface 4010.

[0712] In the illustrated embodiment the fastening bracket 4955 extends around the second distal opening 4906. The fastening bracket is positioned inside the second chamber 3288. The fastening bracket 4955 is on the proximal side of the second rim 4964. The fastening bracket 4955 is a ring that circumscribes the second distal opening 4906. Respiratory gas can flow through a channel created by the fastening bracket 4955. The fastening bracket 4955 may be made of a material more rigid than the seal member 4218. The connection between the fastening bracket 4955 and the outlet panel 4951 compresses the seal member 4218 to create a substantially airtight seal. In this embodiment, the seal member 4218 is clamped between the fastening bracket 4922 and the housing 4950. The fastening bracket may be permanently attached to the seal member 4218 or alternatively held in place with attached to the outlet panel 4951.

[0713] In another embodiment the fastening bracket 4955 may be integral to the seal member 4218. In this embodiment, the fastening bracket 4955 may be over moulded to the seal member 4218 or formed integral to the seal member 4218 through a single shot moulding process.

[0714] The patient interface 4010 further includes the frame 4030 and the conduit connector 40. This frame 4030 is a variation of the frame 30 previously described in that the frame 4030 is attachable directly to the seal member 4218.

[0715] The frame 4030 includes the central body portion 302 that includes one or more passages for conveying respiratory gas from a gas source to the cushion module 4020 and therefore the patient. The one or more passages are in the form of a connector sleeve 4310. The frame 4030 comprises side wings 4304 extending from the central body portion 4302. Each side-wing 4304 comprises a pair of openings 4308 arranged to co-operate with headgear (such as resilient straps) for fitting the patient interface to a patient. The headgear operates by pulling the patient interface 4010 into contact with the patient's face to form a substantially air-tight seal when respiratory gas at elevated gas pressure is delivered to the patient via the patient interface 4010. The opening 4308 on each side wing 4304 includes a bar 4306 for connecting with a headgear clip to allow for easier connection and disconnection from headgear.

[0716] The conduit connector 40 (Figure 2) is the same conduit connector 40 described above in relation to the patent interface 10 and shown in Figures 1 to 5. All the features and functions of the conduit connector 40 described above apply in the same way to the patient interface 4010.

[0717] Figures 46 to 49 show a cross section of a frame 4030 that is co-operable with the seal member 4218. The frame 4030 comprises two components. One component is located within the seal member 4218 and the other component is located externally of the seal member 4218. The two components interact to compress the seal between them and form a substantially air-tight seal. The interaction between the two components may be permanent or releasable. In this embodiment, the frame 4030 comprises a frame body 4302 and a frame clip 4550, the frame clip 4550 is positioned inside the first chamber 3226 around the first distal opening 4902 such that therapy gas can flow through the frame clip 4550. The frame clip 4550 comprises a wall 4559 shaped to fit the contours of the seal member 4218 around the first distal opening 4902. The frame clip 4550 is co-operable with the frame 4030 such that the seal member 4218 is compressed to create a substantially airtight seal. The seal member 4218 defines the distal end of the first chamber 3226 such that the frame attaches directly to the seal member 4218. The seal is formed by contact between the frame 4030 and the seal member 4218. The frame clip 4550 comprises at least one protrusion 4554, the at least one protrusion 4554 is located on the inner edge of the frame clip 4550. The at least one protrusion 4554 is co-operable with the frame body. The at least one protrusion aligns the frame clip 4550 with the frame body 4302.

[0718] In this embodiment, there is no additional housing which forms an intermediate connection between the frame 4030 and the seal member 4218.

[0719] The frame clip 4550 has a shape that complements the frame 4030 at the location where the frame clip 4550 couples to the frame. In this embodiment, the frame clip 4550 is substantially circular. In other embodiments, the frame clip 4550 may be substantially rectangular, oval or trapezoidal.

[0720] The frame clip 4550 may comprise key formations 4214 that are received by cooperating indents 4307 on the connector sleeve 4310 of the frame body 4030 such that the frame clip 4550 and frame body 4030 are aligned in a pre-determined position when removably attached together.

[0721] In another embodiment, the frame 4030 may be a singular component. The seal member 4218 may be pulled over or pushed into the frame 4030 to form a substantially airtight connection. The seal member 4218 in this variation would be made of a substantially elastic material to allow for the temporary deformation. The frame 4030 may further comprise a receiving portion to accommodate the seal member 4218 which is pulled over or pushed into the frame 4030. For example, the receiving portion may be a groove within the frame 4030. The groove is a portion in which the first rim 4213 is seated. This may involve elastically stretching the first rim 4964 about the frame 4030 and allowing it to relax and seat within the groove. The first rim 4213 remains partly elastically stretched when seated in the groove so that the first rim 4213 grips the frame 4030. This creates a substantially airtight seal between the frame 4030 and the first rim 4213. This also contributes to retaining the frame 4030 connected with the seal member 4218 when respiratory therapy pressures are applied to the patient interface 4010.

[0722] Figure 45 shows the seal member 4218 and the frame 4030. The seal member 4218 comprises a first rim 4213 integrally formed as part of the cushion module 4020. The first rim 4213 extends around the first distal opening 4902. The first rim 4213 extends in a distal direction on the outer wall 4288 of the seal member 4218. The first rim 4213 is surrounded at least partially by a first recess 4904 (Figure 44). The first recess 4904 circumscribes the first rim 4213 on the distal face of the seal member 4218. The first recess 4904 is adjacent the first rim 4213 such that the first rim 4213 is disposed between the first distal opening 4902 and the first recess 4904. The first recess 4904 is an integral portion of the seal member 4218, disposed on the outer wall 4288 and recessed around a periphery of the first rim 4213. The first rim 4213 is a portion of the seal member 4218 that has an increased thickness in the proximal-distal direction relative to the first recess 4904. The first rim 4213 extends in a direction that substantially parallel to the flow of therapeutic gas when the patient interface 4010 is in use.

[0723] The frame 4030 comprises a first indent 4031 and a second indent 4032. The second indent 4031 is perpendicular to the first indent 4031. The second indent 4032 is disposed on the frame 4030 and circumscribes the first distal opening 4902 when attached to the cushion module 4020. The second indent 4032 is sized to accommodate the first rim 4213 such that the first rim 4213 is received by the second indent 4032. The second indent 4032 facilitates a substantially airtight seal between the frame 4030 and the first rim 4213, wherein the first rim 4213 is positioned within the second indent 4032 of the frame body 4302. In this way, the first rim 4213 is compressed to create a seal between the first rim 4213 and the second indent 4032. In other words, the first rim 4213 formed by the seal member 4218 complements the second indent 4032 of the frame body 4302.

[0724] In some embodiments, the frame 4030 may only have a first indent 4031. In this case, the seal member 4218 may not comprise a first rim 4213 such that the frame body 4302 sits flush with the seal member 4218 when attached together and a substantially airtight seal is maintained.

[0725] The first indent 4031 is located on the frame body 4302 such that the frame clip 4550 is co-operable with the first indent 4031. The connection between the two components may be a snap fit connection. In other embodiments, the connection may involve the frame clip 4550 being adhered, welded or mechanically fastened to the seal member 4218. In some embodiments, the frame clip 4550 may be an integral part of the seal member 4218.

[0726] In another embodiment, the frame clip 4550 may be permanently attached to the frame body 4032 once assembled. The permanent attachment may take the form of a permanent mechanical connection, or may be adhered and / or welded.

[0727] Figure 47 shows the frame clip 4550 and two protrusions 4554 located on opposing edges of the frame clip 4550. The protrusions 4554 have a proximal flat faces and a distal slanted faces. These to facilitate a snap-fit connection between the frame body 4302 and the frame clip 4550. The slanted face allows the connector sleeve 4310 of the frame body 4302 to slide through and over the protrusions of the frame clip 4550. The flat edge stops the connector sleeve 4310 from returning through the frame clip 4550 thereby creating a snap-fit connection.

[0728] The frame clip 4550 may comprise key formations 4214 shaped to be received by receiving structures on the connector sleeve of the frame body 4302. The key formations 4550 aid in aligning the frame clip 4550 and frame body 4302 into a predetermined position when attached to each other. The key formations 4214 aid with aligning the protrusions 4554 with the first indents 4031 on the connector sleeve 4310.

[0729] In another embodiment, the frame clip 4550 may be integral to the seal member 4218. In this embodiment, the connector sleeve 4310 is attached to the seal member 4218 by pressing the connector sleeve 4310 through the first distal opening 4902. The frame clip 4550 may be made of a material more rigid than the seal member 4218. The frame clip 4550 may be made of plastic and moulded in a single shot moulding process.

[0730] In Figure 50, a contour 4289 on the seal member 4218 surrounds the housing 4950 and the part of the seal member 4218 which forms the distal end of the first chamber 3226. The contour 4289 circumscribes the outer wall 4288 of the seal member 4218. The first rim 4218 may be a thickened region of the seal member 4218 on the outer wall 4288 that extends in a direction that is distal of the first distal opening 4902. The first rim 4218 may be the most rigid part of the seal member 4218 on the outer wall 4288. This relative rigidity assists for the connection between the frame body 4302 and frame clip 4550.

[0731] In another embodiment, the seal member 4218 of the outer wall 4288 comprises one or more internal support structures to resist deformation of the seal member 4218 into the first chamber 3226. In this embodiment, the support structures may be in the form of materials relatively more rigid than the seal member 4218. The support structures may be ribs or braces. The support structures may extend across the seal member to resist substantial deformation. In other embodiments, the support structures may be formed of elastomeric material. The elastomeric material may be reinforced. The reinforcement is sufficient to provide structural support to the seal member 4218. The reinforcement may be provided by regions of increased wall thickness or by inclusions formed of a relatively more rigid material.

[0732] The anti-asphyxiation valve 70 includes a valve seat 702 and a valve seal 714. The valve seat 702 includes a sealing surface 704 against which the valve seal 714 seals the valve 70. The valve seat 702 further includes a sleeve 708 with a radially outwardly projecting bead 710. The bead 710 is at the end of the sleeve 708. The valve seat 702 further includes a spigot 712 for coupling with the valve seal 714.

[0733] The valve seal 714 includes a flap 720 which can transition between an open position in which the elbow 60 is open to flow of respiratory gas from a source and a closed position in which the elbow 60 is closed to flow of respiratory gas from a source. In the open position, access of ambient air to the inside of the elbow 60 is inhibited and in the closed position, access of ambient air to the inside of the elbow 60 is permitted. In this embodiment, the flap 720 is formed of a flexible material. The flap 720 is joined to a lug 716 by a hinge 722. The hinge 722 comprises a section of flexible material with a reduced wall thickness. The lug 716 is configured to assist with locating the valve seal 714 within the end of the second conduit portion 608. Additionally, the lug 716 includes a recess 718 which is adapted to receive the spigot 712. Mating of the spigot 712 within the recess 718 correctly orients the valve seal 714 on the valve seat 702.

[0734] When pressurised respiratory gas is supplied from a source, it flows through the elbow 60 and into the cushion module 20, 120, 220, 230. The elevated pressure of the respiratory gas causes the flap to swing about the hinge 722 to cover the opening 612 in the second conduit portion. This represents the "open position" described above in that the flap 720 prevents ambient air from entering the elbow 60 via the gap 618 and the opening 612. In the event that the source of respiratory gas fails or the conduit connecting to the source becomes obstructed, the anti-asphyxiation valve 70 closes because the air pressure in the elbow 60 equalises with the air pressure outside the elbow 60 so that the flap 720 transitions to the "closed position" described above owing to the inherent resilience in the flexible material which forms the hinge 722. In the closed position, the opening 612 is revealed to the interior of the elbow 60 so that the natural breathing cycle of the patient will draw air into the elbow 60 and the cushion module 20, 120, 220, 230 via the one or more openings as shown by the flow arrows in Figure 5.

[0735] The valve seat 702 includes a radially projecting step which is configured to couple with the elbow 60. In particular, the step 724 is configured to fit with the end of the second conduit portion 608. The coupling may comprise a snap-fit connection or may comprise a permanent fixing, such as welding or fixing with adhesive.

[0736] The valve seat 702 couples with a swivel connector 80 which is configured to connect with a conduit from a respiratory gas source. The swivel connector 80 includes a radially inwardly projecting shoulder 82 which is co-operable with the step 724 of the valve seat 714 to connect the valve seat 714 to the swivel connector 80. The connection is a snap- fit connection. In other embodiment, however, the connection may comprise a permanent fixing, such as welding or fixing with adhesive.

[0737] Those skilled in the art of the present invention will appreciate that many variations and modifications may be made to the preferred embodiment without departing from the spirit and scope of the present invention.

[0738] In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word "comprise" and variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the apparatus and method as disclosed herein.

[0739] In the foregoing description of preferred embodiments, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "front" and "rear", "inner" and "outer", "above", "below", "upper" and "lower", "underside" and "topside", "vertical" and "horizontal" and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms. These terms when used in reference to the patient interface throughout the specification, including the claims, refer to orientations relative to an upright orientation, i.e. when the patient interface is fitted to a patient and the patient's head is upright.

[0740] Furthermore, invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Also, the various embodiments described above may be implemented in conjunction with other embodiments, for example, aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.

Claims

CLAIMS1. A non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :• an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares, the outer wall including a proximal side that includes a patient-contact surface and a distal side at an opposite side of the outer wall to the proximal side; and• a dividing wall that separates the first chamber from the second chamber, the dividing wall includes a first resilient region that is linked to the distal side of the outer wall, a second resilient region that is linked to the proximal side of the outer wall and a deformation panel linking the first and second resilient regions; and• one or more flow directors which enable gas to flow into the second chamber from the first chamber and which flow directors are configured to direct the gas flow towards the one or more nare openings; and wherein at least part of the first resilient region is at a level that is lower than a level of at least part of the second resilient region, having regard to a generally upright orientation of the patient interface.

2. The non-invasive patient interface defined in claim 1, wherein the first resilient region and the deformation panel meet at a level that is lower than the level where the second resilient region and the deformation panel meet.

3. The non-invasive patient interface defined in claim 1, wherein the first resilient region and the deformation panel meet at a level that is below a level where the second resilient region and the deformation panel meet at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to a generally upright orientation of the patient interface.

4. The non-invasive patient interface defined in claim 1, wherein the first resilient region and the deformation panel meet at a level that is below, having regard to a generally upright orientation of the patient interface, the level where the secondresilient region and the deformation panel meet at each respective lateral location between laterally outer-most edges of the one or more nare openings.

5. The non-invasive patient interface defined in any one of claims 1 to 4, wherein at least part of the first resilient region decreases in wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

6. The non-invasive patient interface defined in any one of claims 1 to 4, wherein at least part of the first resilient region includes a generally constant wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

7. The non-invasive patient interface defined in any one of claims 1 to 4, wherein at least part of the first resilient region increases in wall thickness in a distal direction between where the deformation panel and the first resilient region meet and the distal side of the outer wall.

8. The non-invasive patient interface defined in any one of the preceding claims, wherein the first resilient region includes a second chamber surface exposed to the second chamber and the second resilient region includes a second chamber surface exposed to the second chamber.

9. The non-invasive patient interface defined in claim 8, wherein the first resilient region includes a central region between the lateral edges of the second distal opening and the first resilient region includes lateral regions that are laterally adjacent to the central region.

10. The non-invasive patient interface defined in claim 9, wherein the second chamber surface of the first resilient region in the central region is inclined relative to the deformation panel at an angle that is less than the angle between the deformation panel and the lateral regions of the first resilient region.

11. The non-invasive patient interface defined in claim 9 or claim 10, wherein part of the central region includes a cross-sectional shape in the lateral direction that is U- shaped or W-shaped.

12. The non-invasive patient interface defined in any one of claims 8 to 11, wherein at least at a vertical mid-plane through the patient interface in the proximal distal direction, having regard to an upright orientation of the patient interface, the second chamber surface of the first resilient region is inclined at an obtuse angle relative to the orientation of the deformation panel at a location where they meet.

13. The non-invasive patient interface defined in any one of claims 8 to 12, wherein a centreline in the proximal-distal direction across the second chamber surface of the second resilient region is parallel to or within + / - 20° of a centreline in the proximal- distal direction across the second chamber surface of the first resilient region.

14. The non-invasive patient interface defined in any one of the preceding claims, wherein a vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel is constant along the width of the deformation panel.

15. The non-invasive patient interface defined in any one of claims 1 to 13, wherein the vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel varies along the width of the deformation panel.

16. The non-invasive patient interface defined in any one of claims 1 to 13, wherein The vertical spacing, having regard to a generally upright orientation of the patient interface, between the first and second resilient regions where they respectively link to the deformation panel decreases in a direction laterally outwardly from a centreline in the proximal-distal direction through the first resilient region.

17. The non-invasive patient interface defined in any one of the preceding claims, wherein the patient interface includes a seal member and a housing which together define the outer wall.

18. The non-invasive patient interface defined in claim 17, wherein the seal member includes the dividing wall.

19. The non-invasive patient interface defined in claim 17 or claim 18, wherein the dividing wall is integrally formed with the seal member.

20. The non-invasive patient interface defined in any one of claims 17 to 19, wherein the seal member includes a first distal opening in the first chamber, the first distal opening being defined by a first rim and the seal member includes a second distal opening in the second chamber, the second distal opening being defined by an upper rim portion and a lower rim portion which meet at respective lateral edges, having regard to a generally upright orientation of the patient interface.

21. The non-invasive patient interface defined in claim 20, wherein the first distal opening extends laterally beyond the lateral edges of the second distal opening.

22. The non-invasive patient interface defined in claim 20 or claim 21, wherein the first resilient region includes a lateral profile that follows the contour of the lower rim portion between the lateral edges of the second distal opening.

23. The non-invasive patient interface defined in any one of the preceding claims, wherein the proximal side of the outer wall includes a lip superior wall portion between the one or more nare openings and the one or more oral openings and which is configured to contact a patient's lip superior between the patient's nares and mouth, the lip superior wall portion is defined laterally between the laterally outer-most edges of the one or more nare openings.

24. The non-invasive patient interface defined in claim 23, wherein the second resilient region links to the proximal side of the outer wall at least in part at the lip superior wall portion.

25. The non-invasive patient interface defined in any one of the preceding claims, wherein the dividing wall includes a forward panel and a rearward panel, the forward panel includes the first resilient region, links to the distal side of the outer wall and is distal of the deformation panel and the rearward panel includes the second resilient region, links to the proximal side of the outer wall and is proximal of the deformation panel.

26. The non-invasive patient interface defined in claim 25, wherein the forward and rearward panels meet along a notional line that extends laterally beyond the deformation panel to the outer wall and the notional line is contiguous with the link between the forward panel and the deformation panel.

27. The non-invasive patient interface defined in claim 25 or claim 26, wherein the second resilient region of the rearward panel links with the deformation panel.

28. The non-invasive patient interface defined in any one of claims 25 to 27, wherein the distal end of the second resilient region includes a curved shape in the plane of the rearward panel.

29. The non-invasive patient interface defined in claim 28, wherein the link between the deformation panel and the rearward panel at least partly follows the curved shape of the distal end of the second resilient region.

30. The non-invasive patient interface defined in any one of claims 25 to 29, wherein the second resilient region includes a wall thickness that is greater than the wall thickness of the remainder of the rearward panel.

31. The non-invasive patient interface defined in any one of claims 25 to 30, wherein the rearward panel includes a wall thickness that is greater than a wall thickness of the deformation panel.

32. The non-invasive patient interface defined in any one of the preceding claims, wherein the rearward panel meets the outer wall along a line at a level within a notional band defined between the lowest level of the one or more nare openings and uppermost level of the one or more oral openings.

33. The non-invasive patient interface defined in claim 32, wherein part of the first resilient region meets the outer wall outside of the notional band and another part of the first resilient region meets the outer wall within the notional band.

34. The non-invasive patient interface defined in claim 33 when dependent upon claim 20, wherein the first resilient region meets the outer wall adjacent to part of the contour of the first rim laterally beyond the lateral edges of the second distal opening.

35. The non-invasive patient interface defined in claim 32, wherein the first resilient region that is laterally beyond the lateral edges of the second distal opening links with the outer wall within the notional band.

36. The non-invasive patient interface defined in any one of the preceding claims, wherein the second resilient region includes the one or more flow directors.

37. The non-invasive patient interface defined in claim 36, wherein the one or more flow directors are within a footprint of the second resilient region.

38. The non-invasive patient interface defined in claim 36, wherein the one or more flow directors are partly within a footprint of the second resilient region.

39. The non-invasive patient interface defined in claim 32 when dependent upon claim 23, wherein the one or more flow directors are spaced from the lip superior wall portion.

40. The non-invasive patient interface defined in any one of the preceding claims, wherein the deformation panel includes a cross-section with a straight section and a bend and the forward panel meets the straight section and rearward panel meets the bend.

41. The non-invasive patient interface defined in any one of the preceding claims, wherein the first resilient region decreases in wall thickness in the proximal direction.

42. The non-invasive patient interface defined in claim 41, wherein part of the first resilient region decreases in wall thickness in the proximal direction.

43. The non-invasive patient interface defined in claim 41 when dependent upon claim 20, wherein a portion of the first resilient region extending proximally of the lower rim portion of the second distal opening decreases in wall thickness in the proximal direction.

44. The non-invasive patient interface defined in claim 41, wherein in a vertical midplane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the cross-section of the first resilient region decreases in wall thickness in the proximal direction.

45. The non-invasive patient interface defined in any one of the preceding claims, wherein the first resilient region is inclined downwardly, having regard to an upright orientation of the patient interface, from the deformation panel to the outer wall.

46. The non-invasive patient interface defined in claim 8, wherein at least part of the second chamber surface of the first resilient region is inclined downwardly, havingregard to an upright orientation of the patient interface, from the deformation panel to the outer wall.

47. The non-invasive patient interface defined in claim 23 when dependent upon claim 8, wherein at least part of the second chamber surface of the second resilient region is inclined downwardly, having regard to an upright orientation of the patient interface, from the lip superior wall portion toward the deformation panel.

48. The non-invasive patient interface defined in claim 8, wherein at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the second chamber surface of the first resilient region is inclined upwardly in the proximal-distal direction from the deformation panel to the outer wall.

49. The non-invasive patient interface defined in any one of the preceding claims, wherein the second resilient region is spaced from the deformation panel.

50. The non-invasive patient interface defined in claim 49, wherein the bend in the deformation panel is an inflection point in the dividing wall between the first and second resilient regions.

51. The non-invasive patient interface defined in claim 49, wherein the wall thickness of the dividing wall between the second resilient region and the deformation panel is less than the wall thickness of the second resilient region to enable the inflection point to shift proximally toward the second resilient region when the second resilient region advances in a distal direction relative to the first resilient region.

52. The non-invasive patient interface defined in claim 49 when dependent upon claim 25, wherein the wall thickness of at least part of the rearward panel between the second resilient region and the deformation panel decreases in the direction from the second resilient region to the deformation panel.

53. The non-invasive patient interface defined in any one of the preceding claims, wherein at least part of the deformation panel includes a cross-section with a curved segment which links with the first resilient region.

54. The non-invasive patient interface defined in claim 53, wherein the first resilient region includes a first chamber surface that is exposed to the first chamber and acurvature of at least part of the first chamber surface of the first resilient region is contiguous with the curvature of the curved segment.

55. The non-invasive patient interface defined in claim 8, wherein at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the deformation panel meets the second chamber surface of the first resilient region at a location that is at or above the level of an upper-most portion of the one or more oral openings.

56. The non-invasive patient interface defined in claim 8, wherein at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, the deformation panel meets the second chamber surface of the first resilient region below the level of an uppermost portion of the one or more oral openings.

57. The non-invasive patient interface defined in claim 23, wherein the vertical dimension of the deformation panel, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, is in the range of 80-120% of the vertical dimension of the lip superior wall portion, at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

58. A non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :• an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares, the outer wall including a proximal side that includes a patient-contact surface and a distal side at an opposite side of the outer wall to the proximal side; and• a dividing wall that separates the first chamber from the second chamber, the dividing wall includes a first resilient region that is linked to the distal side of the outer wall, a second resilient region that is linked to the proximal side of the outer wall and a deformation panel linking the first and second resilient regions; and• one or more flow directors which enable gas to flow into the second chamber from the first chamber and which flow directors are configured to direct the gas flow towards the one or more nare openings; and wherein at least part of the dividing wall is curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface.

59. The non-invasive patient interface defined in claim 58, wherein the dividing wall is curved downwardly in laterally outward direction across substantially its entire length in a proximal-distal direction, having regard to an upright orientation of the patient interface.

60. The non-invasive patient interface defined in claim 58, wherein at least part of the dividing wall is curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the flow directors.

61. The non-invasive patient interface defined in claim 58, wherein at least part of the dividing wall is curved downwardly in a laterally outward direction, having regard to an upright orientation of the patient interface, on either side of the first resilient region.

62. The non-invasive patient interface defined in claim 58, wherein at least part of the dividing wall is curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

63. The non-invasive patient interface defined in any one of claims 58 to 62, wherein part of the dividing wall meets the outer wall at a level that is below a level more than one-third of the distance between upper-most and lower-most rim portions of the one or more oral openings from the upper-most rim portion, having regard to an upright orientation of the patient interface.

64. The non-invasive patient interface defined in any one of claims 58 to 62, wherein part of the dividing wall meets the outer wall at a level that is approximately half the distance between upper-most and lower-most rim portions of the one or more oral openings, having regard to an upright orientation of the patient interface.

65. The non-invasive patient interface defined in any one of claims 58 to 62, wherein part of the dividing wall meets the outer wall at a level that is below a level that is halfthe distance between upper-most and lower-most rims of the one or more oral opening, having regard to an upright orientation of the patient interface.

66. The non-invasive patient interface defined in any one of claims 58 to 62, wherein part of the dividing wall meets the outer wall at a level that is below a lower-most level of the first resilient region, having regard to an upright orientation of the patient interface.

67. The non-invasive patient interface defined in any one of claims 58 to 66, wherein the dividing wall forms an arc when viewed from the first distal opening.

68. The non-invasive patient interface defined in any one of claims 58 to 67, wherein the proximal side of the outer wall includes a lip superior wall portion between the one or more nare openings and the one or more oral openings.

69. The non-invasive patient interface defined in claim 68, wherein part of the dividing wall meets the outer wall at a level that is below a lowermost level of the lip superior wall portion, having regard to an upright orientation of the patient interface.

70. The non-invasive patient interface defined in any one of claims 58 to 69, wherein the dividing wall includes a forward panel and a rearward panel, the forward panel includes the first resilient region and links to the distal side of the outer wall and is distal of the deformation panel, the rearward panel includes the second resilient region and links to the proximal side of the outer wall and is proximal of the deformation panel.

71. The non-invasive patient interface defined in claim 70, wherein, in the lateral direction, the forward panel is curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

72. The non-invasive patient interface defined in claim 70 or claim 71, wherein, in the lateral direction, the rearward panel is curved downwardly from a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

73. The non-invasive patient interface defined in any one of claims 70 to 72, wherein, in the lateral direction, the deformation panel is curved downwardly from avertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface.

74. The non-invasive patient interface defined in any one of claims 58 to 73, wherein the patient interface includes a first distal opening in the first chamber which is defined by a first rim and includes a second distal opening in the second chamber.

75. The non-invasive patient interface defined in claim 74, wherein at least parts of the first resilient region that are laterally beyond the first distal opening meet with the outer wall at a level that is below the level of the central region of the first resilient region, having regard to an upright orientation of the patient interface.

76. The non-invasive patient interface defined in claim 74 or claim 75, wherein the first resilient region meets the distal side of the outer wall along a contour that at least partly follows the first rim of the first distal opening.

77. The non-invasive patient interface defined in any one of claims 58 to 76, wherein the second resilient region includes one or more flow directors.

78. A non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :• an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and• a dividing wall that separates the first chamber from the second chamber, wherein the outer wall includes a seal member, a first housing connected to the seal member to form part of the outer wall and a second housing connected to the seal member to form part of the outer wall.

79. The non-invasive patient interface defined in claim 78, wherein the first housing forms part of the outer wall associated with the first chamber and the second housing forms part of the outer wall associated with the second chamber.

80. The non-invasive patient interface defined in claim 78 or claim 79, wherein the seal member is permanently connected to the first housing.

81. The non-invasive patient interface defined in any one of claims 78 to 80, wherein the second housing is removably joined to the seal member or to the first housing.

82. The non-invasive patient interface defined in any one of claims 78 to 80, wherein the seal member is permanently connected to the second housing.

83. The non-invasive patient interface defined in any one of claims 78 to 82, wherein the second housing includes two components that join to one another.

84. The non-invasive patient interface defined in claim 83 when dependent upon claim 82, wherein the seal member is permanently joined to one of the second housing components and the other second housing component is configured to join to the permanently joined component.

85. The non-invasive patient interface defined in claim 83 or claim 84, wherein a part of the seal member is clamped between the two components of the second housing when the two components are joined.

86. The non-invasive patient interface defined in any one of claims 83 to 85, wherein the two components of the second housing are removably joined to one another.

87. The non-invasive patient interface defined in any one of claims 78 to 86, wherein the first housing is below the second housing, having regard to a generally upright orientation of the patient interface.

88. The non-invasive patient interface defined in any one of claims 78 to 88, wherein the first housing and the second housing are spaced apart by part of the seal member.

89. The non-invasive patient interface defined in claim 88, wherein the part of the seal member spacing apart the first and second housing is a transom which is part of the outer wall.

90. The non-invasive patient interface defined in claim 89, wherein the dividing wall includes a first resilient region that is linked to a distal side of the outer wall, a second resilient region that is linked to a proximal side of the outer wall and a deformation panel connecting between the first and second resilient regions and the first resilient region extends in the proximal direction from at least part of the transom.

91. The non-invasive patient interface defined in any one of claims 78 to 90, wherein the dividing wall includes a first resilient region that is linked to a distal side of the outer wall, a second resilient region that is linked to a proximal side of the outer wall and a deformation panel connecting between the first and second resilient regions.

92. The non-invasive patient interface defined in any one of claims 78 to 91, wherein the patient interface includes a first distal opening in the first chamber which is defined by a first rim and includes a second distal opening in the second chamber which is defined by an upper rim portion and a lower rim portion which meet at respective lateral edges, having regard to a generally upright orientation of the patient interface.

93. The non-invasive patient interface defined in claim 92, wherein the second housing is co-operable with the upper rim portion and the lower rim portion of the second distal opening to form a seal between the second housing and the second distal opening.

94. The non-invasive patient interface defined in claim 92 or claim 93, wherein the second housing and the upper rim portion and the lower rim portion of the second distal opening include co-operable seal-forming formations.

95. The non-invasive patient interface defined in any one of claims 92 to 94, wherein the second housing includes an outlet panel and a fastening bracket which are co- operable to form a seal between the second housing and the second distal opening.

96. The non-invasive patient interface defined in claim 95, wherein the outlet panel and the fastening bracket is co-operable to form a seal against the upper rim portion and the lower rim portion.

97. The non-invasive patient interface defined in claim 96, wherein the upper rim portion and the lower rim portion include a rim profile that complements a seal formation on the outlet panel or the fastening bracket.

98. The non-invasive patient interface defined in any one of claims 92 to 97 when dependent upon claim 91, wherein the part of the first resilient region follows the contour of the lower rim portion.

99. The non-invasive patient interface defined in any one of claims 91 to 97, wherein the first resilient region includes a second chamber surface exposed to the second chamber and the second resilient region includes a second chamber surface exposed to the second chamber.

100. The non-invasive patient interface defined in claim 99, wherein at least part of the second chamber surface of the first resilient region at a vertical mid-plane through the patient interface, having regard to an upright orientation of the patient interface, is at or above the level of the upper-most rim portion of the one or more oral openings.

101. The non-invasive patient interface defined in claim 99, wherein at least part of the second chamber surface of the first resilient region at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, is below the level of the upper-most rim portion of the one or more oral openings and is above the opening in the first housing.

102. The non-invasive patient interface defined in any one of claims 78 to 101, wherein the dividing wall includes a forward panel and a rearward panel, the forward panel includes the first resilient region and links to the distal side of the outer wall and is distal of the deformation panel, the rearward panel includes the second resilient region and links to the proximal side of the outer wall and is proximal of the deformation panel.

103. The non-invasive patient interface defined in claim 102, wherein the forward panel and the rearward panel extend laterally to a level that is between the lower-most rim portion of the one or more oral openings and a level half-way between the uppermost rim portion and the lower-most rim portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

104. The non-invasive patient interface defined in claim 102, wherein the forward panel and the rearward panel extend laterally to a level that is between the level of the upper-most portion of the one or more oral openings and a level half-way between the upper-most portion and lower-most portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

105. The non-invasive patient interface defined in any one of claims 78 to 104, wherein an upper portion of the first housing above a notional laterally extending line between the laterally outer-most parts of the first housing includes a radius of curvaturethat is less than a radius of curvature of a basal portion below the notional laterally extending line.

106. The non-invasive patient interface defined in claim 105, wherein at least part of the upper portion follows the first resilient region along the outer wall.

107. The non-invasive patient interface defined in any one of claims 78 to 106, wherein the lateral dimension between the laterally outer-most points of the second housing is within + / -20% of the lateral dimension between the laterally outer-most points of the first housing.

108. The non-invasive patient interface defined in any one of claims 78 to 107, wherein the first housing includes an opening for delivery of respiratory gas into the first chamber and the second housing includes an outlet for exhausting gas from the second chamber.

109. The non-invasive patient interface defined in any one of claims 78 to 108, wherein the patient interface includes one or more flow directors which enable gas to flow into the second chamber from the first chamber.

110. The non-invasive patient interface of any one of claims 78 to 109, wherein the first housing is made of the same material as the seal member.

111. A non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface including :• an outer wall defining an interior volume which includes a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and• a dividing wall that separates the first chamber from the second chamber, wherein a volume ratio of the second chamber to the first chamber is in the range of 0.05: 1 to 0.7: 1.

112. The non-invasive patient interface defined in claim 111, wherein the volume ratio of the second chamber to the first chamber is greater than 0.1 : 1, greater than 0.15: 1, greater than 0.2: 1, greater than 0.25: 1, or greater than 0.3: 1.

113. The non-invasive patient interface defined in claim 111 or claim 112, wherein the volume ratio of the second chamber to the first chamber is less than 0.65: 1, less than 0.6: 1, less than 0.55: 1, less than 0.5: 1, less than 0.45: 1, less than 0.4: 1, or less than 0.35: 1.

114. The non-invasive patient interface defined in any one of claims 111 to 113, wherein the volume of the first chamber is in the range of 90 to 160 cm3.

115. The non-invasive patient interface defined in any one of claims 111 to 114, wherein the area of the one or more nare openings is in the range of 130 to 340 mm2.

116. The non-invasive patient interface defined in any one of claims 111 to 114, wherein the area of the one or more nare openings is in the range of 140 to 330 mm2.

117. The non-invasive patient interface defined in any one of claims 111 to 114, wherein the area of the one or more nare openings is in the range of 150 to 320 mm2.

118. The non-invasive patient interface defined in any one of claims 111 to 117, wherein the dividing wall includes a first resilient region that is linked to a distal side of the outer wall, a second resilient region that is linked to a proximal side of the outer wall and a deformation panel connecting between the first and second resilient regions.

119. The non-invasive patient interface defined in any one of claims 111 to 118, wherein the patient interface includes one or more flow directors which and which flow directors are configured to direct the gas flow towards the one or more nare openings.

120. The non-invasive patient interface defined in claim 119, wherein each of the one or more flow directors includes a gas flow passage to enable gas to flow into the second chamber from the first chamber and the volume of the first chamber includes the volume of the gas flow passages through the one or more flow directors.

121. The non-invasive patient interface defined in any one of claims 111 to 120, wherein the outer wall includes a sleeve which is configured to connect with a frame or a respiratory gas conduit and the volume of the first chamber excludes the volume defined by the sleeve.

122. A non-invasive patient interface which is configured to seal about the mouth and nares of a patient, the patient interface comprising :• an outer wall defining an interior volume which comprises a first chamber having one or more oral openings to communicate gas with the mouth and a second chamber having one or more nare openings to communicate gas with the nares; and• a dividing wall that separates the first chamber from the second chamber,• an inlet configured to convey respiratory gas to the first chamber, wherein the outer wall comprises a seal member and a housing connected to the seal member to form part of the outer wall.

123. The non-invasive patient interface defined in claim 122, wherein the housing forms part of the outer wall associated with the second chamber.

124. The non-invasive patient interface defined in any one of claims 122 to 123, wherein the housing is integrally formed with the seal member.

125. The non-invasive patient interface defined in claim 124, wherein the housing is over-moulded to the seal member.

126. The non-invasive patient interface defined in any one of claims 122 to 123, wherein the housing is removably joined to the seal member.

127. The non-invasive patient interface defined in any one of claims 122 to 126, wherein the housing comprises a groove into which the seal member may be mounted.

128. The non-invasive patient interface defined in claim 126, wherein the housing is removably joined to the seal member via a press fit connection.

129. The non-invasive patient interface defined in any one of claims 122 to 126, wherein the seal member is removably joined to two components of the housing.

130. The non-invasive patient interface defined in any one of claims 122 to 126, wherein the seal member is mounted between the two components of the housing.

131. The non-invasive patient interface defined in any one of claims 129 or 130 wherein the seal member is clamped between the two components of the housing.

132. The non-invasive patient interface defined in any one of claims 122 to 126, wherein the housing is located above the inlet, having regard to a generally upright orientation of the patient interface.

133. The non-invasive patient interface defined in any one of claims 122 to 128, wherein the dividing wall comprises a first resilient region that is linked to a distal side of the outer wall, a second resilient region that is linked to a proximal side of the outer wall and a deformation panel connecting between the first and second resilient regions.

134. The non-invasive patient interface defined in claim 133, wherein the first resilient region extends in a proximal direction from a distal portion of the outer wall.

135. The non-invasive patient interface defined in any one of claim 134 or 134, wherein the first resilient region extends from a region above the inlet.

136. The non-invasive patient interface defined in any one of claims 134 or 134, wherein the first resilient region extends from a region below the housing.

137. The non-invasive patient interface defined in any one of claims 134 or 134, wherein the first resilient region extends from a region between the inlet and the housing.

138. The non-invasive patient interface defined in any one of claims 133 or 134, wherein the second resilient region extends from a region below the second opening.

139. The non-invasive patient interface defined in any one of claims 133 to 138, wherein the second resilient region extends from a region above the first opening.

140. The non-invasive patient interface defined in any one of claim 134 to 139, wherein the first resilient region and the deformation panel meet at a level that is lower than the level where the second resilient region and the deformation panel meet.

141. The non-invasive patient interface defined in any one of claims 133 to 139, wherein the first resilient region and the deformation panel meet at a level that is belowa level where the second resilient region and the deformation panel meet at least at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to a generally upright orientation of the patient interface.

142. The non-invasive patient interface defined in any one of claims 133 to 141, wherein the first resilient region and the deformation panel meet at a level that is below, having regard to a generally upright orientation of the patient interface, the level where the second resilient region and the deformation panel meet at each respective lateral location between laterally outer-most edges of the one or more nare openings.

143. The non-invasive patient interface defined in any one of claims 122 to 142, wherein the patient interface comprises; a first distal opening in the first chamber which is defined by a first rim and; a second distal opening in the second chamber which is defined by a second rim, having regard to a generally upright orientation of the patient interface.

144. The non-invasive patient interface defined in claim 143, wherein the housing is co-operable with the second rim.

145. The non-invasive patient interface defined in claim 143 or claim 144, wherein the housing and the second rim of the second distal opening comprises co-operable seal-forming formations.

146. The non-invasive patient interface defined in any one of claims 143 to 145, wherein the housing comprises an outlet panel and a fastening bracket which are co- operable to form a seal between the housing and the second distal opening.

147. The non-invasive patient interface defined in claim 146, wherein the outlet panel and the fastening bracket are co-operable to form a seal against the second rim.

148. The non-invasive patient interface defined in claim 143, wherein the second rim comprises a rim profile that complements a seal formation on the outlet panel and / or the fastening bracket.

149. The non-invasive patient interface defined in claim 143, wherein the first resilient region comprises a lateral profile that may follow the contour of the second rim portion between the lateral edges of the second distal opening.

150. The non-invasive patient interface defined in any one of claims 122 to 149 wherein the first resilient region comprises a second chamber surface exposed to the second chamber and the second resilient region comprises a second chamber surface exposed to the second chamber.

151. The non-invasive patient interface defined in any one of claims 122 to 150, wherein at least part of the second chamber surface of the first resilient region at a vertical mid-plane through the patient interface, having regard to an upright orientation of the patient interface, is at or above the level of the upper-most rim portion of the one or more oral openings.

152. The non-invasive patient interface defined in any one of claims 122 to 150, wherein at least part of the second chamber surface of the first resilient region at a vertical mid-plane through the patient interface in the proximal-distal direction, having regard to an upright orientation of the patient interface, is below the level of the uppermost rim portion of the one or more oral openings and is above the opening in the first housing.

153. The non-invasive patient interface defined in any one of claims 121 to 152, wherein the dividing wall comprises a forward panel, the forward panel comprises the first resilient region.

154. The non-invasive patient interface defined in any one of claims 121 to 153, wherein the dividing wall comprises a rearward panel, the rearward panel comprises the second resilient region.

155. The non-invasive patient interface defined in any one of claims 153 to 154, wherein the forward panel links to the distal side of the outer wall and is distal of the deformation panel.

156. The non-invasive patient interface defined in any one of claims 153 to 155, wherein the rearward panel links to the proximal side of the outer wall and is proximal of the deformation panel.

157. The non-invasive patient interface defined in claim 140, wherein the forward panel and the rearward panel extend laterally to a level that is between the lower-most rim portion of the one or more oral openings and a level half-way between the upper-most rim portion and the lower-most rim portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

158. The non-invasive patient interface defined in claim 140, wherein the forward panel and the rearward panel extend laterally to a level that is between the level of the upper-most portion of the one or more oral openings and a level half-way between the upper-most portion and lower-most portion of the one or more oral openings, having regard to an upright orientation of the patient interface.

159. The non-invasive patient interface defined in any one of claims 122 to 142, wherein an upper portion of the housing above a notional laterally extending line between the laterally outer-most parts of the housing comprises a radius of curvature that is less than a radius of curvature of a nasal portion below the notional laterally extending line.

160. The non-invasive patient interface defined in any one of claims 122 to 159, wherein the frame comprises a frame body and a frame clip.

161. The non-invasive patient interface defined by claims 160, wherein the frame body comprises a connector sleeve.

162. The non-invasive patient interface defined by claims 160, wherein the frame clip comprises a frame clip wall, the frame clip wall is shaped to fit the internal contours of the outer wall.

163. The non-invasive patient interface defined by claims 161, wherein the frame clip comprises key formations, the connector sleeve comprises receiving structures to receive the key formations such that the frame clip and frame body are aligned in a predetermined orientation when removably attached to each other.

164. The non-invasive patient interface defined in claim 160 or 161, wherein the frame clip comprises a frame clip protrusion co-operable with a first indent of the frame body.

165. The non-invasive patient interface defined in claim 160, wherein the frame clip forms a one-way snap-fit connection with the first indent of the frame body.

166. The non-invasive patient interface defined in any one of claims 160 to 162, wherein a part of the seal member is clamped between the two components of the frame when the two components are joined.

167. The non-invasive patient interface defined in any one of claims 160 to 162 and 164, wherein a part of the seal member is clamped between the frame body and the frame clip when the frame is attached to the seal member.

168. The non-invasive patient interface defined in claim 167, wherein the frame is removably attached to the seal member.

169. The non-invasive patient interface defined in claim 143, wherein the first rim is provided on the outer wall and extends in a direction distal of the first distal opening.

170. The non-invasive patient interface defined in claim 143, wherein the first rim is mounted within a second indent of the frame body.

171. The non-invasive patient interface defined in any one of claims 143, 165 and 166, wherein the first rim is the thickest region of the seal member on the outer wall.

172. The non-invasive patient interface defined in any one of claims 143, 165, 166 and 175, wherein the first rim is the most rigid component of the seal member on the outer wall.

173. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the seal member of the outer wall is the thinnest region of material on the cushion module.

174. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the seal member of the outer wall is rigid such that the seal member of the outer wall resists deformation into the first chamber.

175. The non-invasive patient interface defined in any one of claims 122 to 174, wherein the seal member of the outer wall comprises support structures integral to the seal member such that the seal member does not deform into the first chamber.

176. The non-invasive patient interface defined in any one of claims 122 to 144, wherein the frame comprises an opening and the opening comprises key formations for coupling the frame to a respiratory gas conduit.

177. The non-invasive patient interface defined in any one of claims 122 to 153, wherein the housing is the most rigid component of the outer wall.

178. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the frame is removably attached to the seal member.

179. The non-invasive patient interface defined in claim 169, wherein the frame is removably attached to the seal member via a bayonet fitting.

180. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the frame is permanently attached to the seal member.

181. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the frame is adhered to the seal member.

182. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the seal member is pulled over the frame and attached by compressive forces.

183. The non-invasive patient interface defined in any one of claims 122 to 168, wherein the frame is press-fit into the seal member.

184. The non-invasive patient interface defined in any one of claims 122 to 153, wherein the seal member defines a majority of the distal end of the first chamber.

185. The non-invasive patient interface defined in any one of claims 122 to 144, wherein the first distal opening is provided on the outer wall for delivery of respiratory gas into the first chamber and the housing comprises an outlet for exhausting gas from the second chamber.

186. The non-invasive patient interface defined in any one of claims 122 to 153, wherein the seal member of the outer wall comprises a contour, the contour circumscribes the housing and the first distal opening187. The non-invasive patient interface defined in claim 157, wherein the seal member of the outer wall spans from the contour to the first distal opening, wherein this portion of the outer wall has a decreased thickness relative to the surrounding seal portion.

188. The non-invasive patient interface defined in any one of claims 122 to 153, wherein the outer wall is made of an elastomer.

189. The non-invasive patient interface defined in any one of claims 122 to 185, wherein the patient interface comprises one or more flow directors which enable gas to flow into the second chamber from the first chamber.

190. The non-invasive patient interface defined in claim 189, wherein the dividing wall includes one or more flow directors configured to direct the gas flow towards the nare openings.

191. The non-invasive patient interface defined in claim 189 or 190, wherein the flow directors are spaced apart by a spacing element which maintains a spacing between the flow directors.

192. The non-invasive patient interface defined in any one of claims 189 to 191, wherein the flow directors extend into the first chamber.

193. The non-invasive patient interface defined in any one of claims 189 to 192, wherein the flow directors extend into the second chamber.

194. The non-invasive patient interface defined in any one of claims 189 to 193, wherein the flow directors have a sealed joint with the dividing wall.

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