NZ768957A - Patient interface systems - Google Patents

Abstract

Disclosed is a patient interface system or CPAP ventilation mask for delivery of a supply of air at positive pressure to the entrance of a patient’s airways for treatment of sleep disordered breathing where the straps are configured and fastened to provide a more secure fit to the patients head. The patient interface system comprises a patient interface structure which comprises a seal forming structure configured to sealingly engage a surface of the patient’s face to cover part, or all, of one or more of the patient’s nose and mouth, and a seal positioning and stabilising structure configured to in use connect to the patient interface structure. The seal positioning and stabilising structure comprises a pair of side straps configured to extend along a respective side region of the patient’s face in use, a pair of top straps configured to extend across a top region of the patient’s head, the pair of top straps including a first top strap and a second top strap, a rear strap configured to extend around a rear region of the patient’s head. Each side strap has increased rigidity or stiffness as compared to the rear strap, and the pair of top straps comprises a strap connector for connecting the first strap and the second strap to one another and selectively adjusting a position of the first top strap relative to the second top strap when connected to thereby adjust an effective length of the top straps. The strap connector comprises a first part having a locking projection disposed on the first top strap, and a second part having a plurality of holes disposed in the section top strap, and the locking projection is configured to in use engage with one of the holes to lock the first top strap in position relative to the second top strap.

Description

James & Wells Ref: 504864DIV6 T ACE SYSTEMS CROSS REFERENCE TO RELATED APPLICATIONS This ation claims priority to Australian Applications 2007905737 and 2007906276, filed October 22, 2007 and November 16, 2007, respectively, and U.S. Applications 61/031,173 and 61/129,982, filed February 25, 2008 and August 4, 2008, respectively, the entire contents of each being incorporated herein by reference.

FIELD OF THE INVENTIONS The inventions relate to patient interfaces for delivery of respiratory y to a patient. Examples of such therapies e Continuous Positive Airway Pressure (CPAP), Non- Invasive Positive Pressure Ventilation (NIPPV), and Variable Positive Airway Pressure (VPAP).

The therapy is used for treatment of various respiratory conditions including Sleep Disordered Breathing (SDB), for example ctive Sleep Apnea (OSA).

BACKGROUND OF THE IONS 1. INTRODUCTION The provision of a supply of air at positive pressure to the entrance of a patient's airways for treatment of SDB was first disclosed in U.S. Patent 310 to an. The delivery of the pressurized flow is facilitated by a patient interface, such as a mask. Mask systems may be classified as "nasal masks," "full-face masks," "nose and mouth masks" and a variety of nozzle designs, including "nasal pillows," "nasal puffs," "nasal prongs" and "nasal cannulae" designs. An example of a nasal -type mask system is disclosed in WO 2004/073778 (Gunaratnam et al.), the contents of which are hereby incorporated by reference.

While different manufacturers use different terminology to refer to different components, patient interfaces systems, also called mask systems, typically comprise: (i) a cushioning element (ii) a headgear system to position and retain the cushioning element in position; James & Wells Ref: DIV6 (iii) a rigid structure, known as a frame or shell; and (iv) an air delivery tube. 1.1 Cushioning Element The cushioning element, or cushion, generally includes a soft, conforming structure made from a material such as a silicone, a gel, or a foam. In use the cushion is held against the appropriate part of the face to effect a seal. The cushioning element should form an adequate seal with the entrance to the airways in order to maintain ient air pressure for splinting open the s. In some cases it may not be ary to form a complete seal ed an adequate supply of air can be provided at appropriate pressures and flow rates for effective therapy.

Nasal pillows and nasal puffs form a seal on the outside of the nares, whereas nasal prongs and nasal cannulae are positioned further into the nares and may form a seal on an inside surface of a nare, rather than an outside surface. The location of the seal is a consideration because different es have different orientations, meaning that the force vector needed to form a seal may have a different ion. This may result in a headgear that is appropriate for one design being opriate for another. Furthermore, different seal types may be preferred by different patients, and may be regarded as being more comfortable by some patients. 1.2 Headgear System A mask system typically further comprises a range of frame and headgear systems intended to provide force vectors of appropriate magnitude and direction to hold the cushion in place. 1.3 Frame Many mask systems include a rigid, or semi-rigid, structure referred to as a shell or frame. Together the cushioning t and the frame may define a chamber. Typically, the cushion, headgear and an air delivery tube are attached to the frame. The frame serves as an anchoring point for the cushion, headgear and tube. Past efforts in mask design have been directed towards isms for anchoring the frame in a fixed position with respect to the face James & Wells Ref: 504864DIV6 and then attaching the cushion to the frame to form a seal. 1.4 Tube Many mask systems require some form of tube, hose, or conduit to deliver the flow of air to the mask for ing by the patient. In use, tube drag forces can disrupt the effectiveness of the seal. This can be the result of the weight of the tube and/or movement of the patient.

While tube drag can be alleviated to some extent by the use of swivels, ball and socket , and tube anchoring arrangements, many patients feel the need to over-tighten headgear straps in an t to reduce the problem, leading to discomfort. 2 PRIOR ART Design of an effective respiratory mask system requires consideration of many factors.

Apparently subtle changes may improve or decrease comfort or effectiveness.

While millions of people suffer from the condition of sleep disordered breathing, many fail to comply with therapy because of problems with comfort, ease of use, stability, leak, and obtrusiveness, and thus expose themselves to health risks.

Some prior art mask s attempt to anchor a rigid frame in a fixed position with respect to the face and e patients to increase headgear tension to a level sufficiently high to overcome the seal disruptive effects of patient movement, and/or tube drag.

Whilst some smaller t interfaces (such as some nasal puffs, and some nasal prongs) may be less obtrusive than larger masks (such as a ace mask) they can suffer from a lack of stability. Interface stability of such smaller interfaces was improved by holding the frame in a fixed position in front and below the patient’s nares. The cushion, including the nozzles, extends from this frame to the nares. The frame was held in a rigid fashion (i.e. a set location) aiming to ensure correct alignment of the pillows.

Some prior art t interfaces included swivel elbows or ball-and-socket joints.

Some headgear designs incorporated semi-rigid elements that increased stability of the mask frame. Some frames were designed having a horizontally l tube attachment point.

James & Wells Ref: 504864DIV6 Some prior patient interfaces have required patients to increase headgear tension forces to a high level in an t to overcome disruptive forces. This can lead to excessive forces on sensitive regions of the face, ing in discomfort to the patient.

Referring to Fig. 1, a prior art atory mask system may include a cushion 24 comprising, for example, nasal pillows. The cushion 24 is supported on a rigid frame or shell 18 and a flexible component 22, for example a gusset, is provided between the cushion 24 and the frame 18. An air delivery hose or tube 16 is ted to the frame 18 for the delivery of the flow of pressurized breathable gas. A rigid headgear 20 is connected to the frame 18 to maintain the cushion 24 in sealing contact with the nose of the patient 1. ns which may be used in such a prior art respiratory mask system as shown in Fig. 1 include those disclosed, for example, in ResMed Ltd.’s Swift® LT.

Fig. 2 schematically illustrates another respiratory mask system according to the prior art, the Fisher & Paykel ty® 481 mask. A cushion 24 comprising nasal prongs 23 is attached to a mask frame or shell 18. The mask frame includes headgear connectors 26 provided on sides of the mask frame 18. A vent including a plurality of vent holes 28 is also provided in the mask frame 18.

The mask frame 18 is connected to an air ry hose or tube 16 by a swivel elbow 17. The air delivery tube 16 is connected to a flow of pressurized breathable gas, such as generated by a blower or flow tor, by a coupling element 30.

As the headgear is connected to the mask frame 18 by the headgear connectors 26, any relative movement between the mask frame 18 and the patient’s face may result in a disruption of any seal that may have formed.

SUMMARY OF THE INVENTION One aspect relates to providing comfortable, stable, effective, unobtrusive patient interface systems for delivering a supply of air at positive pressure to the entrance of a patient's airways. Another aspect relates to a patient interface system that fits a wide range of patients, has James & Wells Ref: 504864DIV6 improved manufacturability and improved ease-of-use. r aspect relates to providing patient interface systems where forces applied to the patient interface structure, such as from tube drag forces or movement of the patient, does not disrupt the seal between the patient interface structure and the patient’s airways.

Yet another aspect relates to providing patient interface systems where the patient interface structure, which includes a seal, and a seal positioning and izing structure are coupled to the patient and the air delivery tube is decoupled from the seal. Another aspect is that forces on an air delivery tube and elbow are decoupled from pillows and headgear.

A further aspect relates to patient interface systems in which tension of the seal positioning and stabilizing ure may be set with a lesser regard to overcoming tube drag as the effects of tube drag are isolated from disrupting the seal via decoupling. Thus in accordance with this aspect, the tension of the seal positioning and stabilizing structure may be reduced and patient comfort increased.

Still r aspect relates to providing patient ace systems in which the patient interface structure is connected to a swivel elbow assembly without the use of a rigid frame or shell.

Another aspect of the present technology is a conforming patient interface structure that reduces the number of, or does not include, rigid components. For e, in one form the patient interface does not include a rigid frame.

Another aspect of the present logy is a patient interface structure that in use flexibly wraps around an underside of a patient’s nose and accommodates different alar angles. r aspect of the present technology is a patient interface ure that accommodates movement of an air ry tube whilst maintaining an effective seal.

Another aspect of the present technology is a stabilizing structure that s a seal effecting force to a region close to the g surface, e.g. the base of the nose. A force close to the g surface reduces a bending arm.

James & Wells Ref: 504864DIV6 According to yet r aspect of the technology, a front portion of a seal positioning and stabilizing structure is molded from a le polymer, for example silicone. ably, the seal positioning and stabilizing structure does not include hard plastic stabilizers.

According to a sample embodiment, a patient interface system for delivery of a supply of air at positive pressure to the ce of a patient's airways for treatment of sleep disordered ing comprises an air ry tube connected to a flexible portion of a plenum; a vent structure having sufficient ty to support its own weight under gravity and/or not to block or fold under tube movement or tube drag; a patient interface structure, the patient interface structure comprising a seal forming structure arranged on a top portion of the plenum; and a seal positioning and stabilizing structure ted to a flexible portion of the plenum, wherein the seal-forming ure is substantially led from a tube drag force.

According to another sample embodiment, a nasal pillow for delivery of a supply of air at positive pressure to the entrance of a patient's airways for treatment of sleep disordered breathing comprises a stalk; a frusto-conical portion connected to the stalk at a base portion of the frusto-conical portion, the frusto-conical portion sing a spring ure at base of the frusto-conical portion configured to engage the top lip of the patient and rotate the stalk away from the t’s top lip.

According to yet another sample embodiment, a patient interface structure for delivery of a supply of air at positive pressure to the ce of a patient’s airways for treatment of sleep disordered breathing comprises a le base portion; a seal-forming structure connected to base portion; and lateral connectors connected to the flexible base portion substantially in a same plane as a base of the seal-forming structure, wherein the flexible base portion comprises a flexible side-walled plenum comprising an orifice adapted to receive the supply of air, the orifice having an axis substantially parallel to an axis of the seal-forming structure.

According to a further sample embodiment, a decoupling assembly for decoupling forces applied by a tube on a patient interface structure configured to deliver of a supply of air at James & Wells Ref: 504864DIV6 positive pressure to the entrance of a patient’s airways for treatment of sleep disordered breathing, the patient interface structure comprising a flexible base n connected to a sealforming structure, the patient interface structure being held in engagement with the patient in use by a seal positioning and stabilizing structure connected to the flexible base portion, the decoupling assembly comprising the flexible base portion, the seal-forming structure, and at least one of a n of the seal positioning and stabilizing structure, a swivel elbow, a ball and socket, a swivel sealing ring, and the tube.

According to a still further sample embodiment, a seal positioning and stabilizing structure for a patient interface structure for ry of a supply of air at positive pressure to the entrance of a t’s airways for treatment of sleep disordered breathing comprises a flexible molded strap comprising a stiffened portion.

In another aspect of the disclosure, a patient interface d to be connected to an air delivery tube comprises an under-the-nose gas delivery unit and a plurality of components operatively d to the gas delivery unit, said components including headgear, a plenum, frame, or base, and an elbow; and a decoupling system to decouple (or alternatively means for decoupling) at least a n of a drag (or other dynamic force) from the air ry tube which would ise be applied to the gas ry unit. The gas delivery unit may be in the form of nasal prongs which are inserted into the nares to form a seal within the wearer's nasal es, s that seal against the lower, exterior surface of the nares, or nasal cannulae (which are partly inserted into the nasal passages but do not arily form a seal therewith). The nozzles may include stalks, heads or other structure to help contribute to decoupling of drag or other dynamic forces. The plurality of components may also include a sealing ring which may contribute to decoupling of tube drag force. The decoupling system (or means for decoupling) may include two or more (or all) of said components (as well as the gas delivery unit itself, e.g, various portions of nozzles) working in concert with one another to decouple the force from the gas delivery unit.

James & Wells Ref: 504864DIV6 Other aspects, features, and advantages will become nt from the following detailed ption when taken in conjunction with the accompanying gs, which are a part of this disclosure and which illustrate, by way of example, other aspects and principles.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings facilitate an understanding of the various embodiments, wherein: Fig. 1 schematically depicts a t interface system according to the prior art; Fig. 2 schematically illustrates a patient interface system ing to the prior art; Fig. 3a schematically depicts a patient interface system according to a sample embodiment; Fig. 3b schematically illustrates a vector provided by sample embodiments; Fig. 4 schematically rates a patient ace structure according to a sample embodiment; Fig. 5a schematically illustrates a patient interface system according to r sample embodiment; Fig. 5b schematically illustrates a flexible elbow according to a sample embodiment; Figs. 5c and 5d schematically illustrate an elbow configuration according to a sample embodiment; Fig. 6 schematically illustrates a patient interface system according to another sample embodiment; Fig. 7a schematically illustrates a t interface system according to other sample embodiments; Figs. 7b and 7c schematically illustrate straps according to sample embodiments; Fig. 7d schematically illustrates a patient interface structure according to a sample embodiment; Fig. 8a schematically illustrates a patient interface structure including nasal pillows in James & Wells Ref: 504864DIV6 accordance with a sample embodiment; Fig. 8b tically illustrates a connector of a t interface structure according to a sample embodiment; Fig. 8c schematically illustrates a patient ace structure including nasal pillows in ance with another sample embodiment; Fig. 8d schematically illustrates a patient interface structure including nasal pillows in accordance with another sample embodiment; Fig. 8e schematically illustrates a t interface structure including nasal pillows in accordance with another sample embodiment; Fig. 8f schematically illustrates a patient interface structure including nasal pillows in accordance with another sample embodiment; Fig. 8g schematically illustrates a patient interface structure including nasal pillows in accordance with another sample embodiment; Fig. 8h schematically rates a linking element of the patient ace structure of Fig. 8f; Fig. 8i tically illustrates a patient interface structure including nasal pillows in accordance with another sample embodiment; Fig. 8j schematically illustrates the linking element of the patient interface structure of Fig. 8i; Figs. 8k schematically illustrates a t interface structure ing nasal pillows in accordance with another sample embodiment; Figs. 8l and 8m schematically illustrate a comparison between sample embodiments; Fig. 8n schematically illustrates a patient interface structure including nasal pillows in accordance with another sample embodiment; Figs. 9a and 9b schematically illustrate a patient interface structure to elbow or frame connection in accordance with a sample embodiment; James & Wells Ref: DIV6 Fig. 10 tically depicts a patient interface system according to a sample ment; Fig. 11 schematically depicts a patient interface system according to a sample embodiment; Figs. 12a and 12b schematically illustrate a side view and a rear view, respectively, of a patient interface system according to another sample embodiment; Figs. 13a and 13b schematically rate a side view and a rear view, respectively, of a patient interface system according to another sample embodiment; Figs. 14a and 14b schematically rate a side view and rear view, respectively, of a patient interface system according to another sample embodiment; Figs. 15a and 15b schematically illustrate a side view and rear view, respectively, of a patient interface system according to another sample embodiment; Figs. 16a - 16g schematically illustrate left and right main straps of a main strap loop of a seal oning and stabilizing structure according to a sample embodiment; Figs. 17a – 17g schematically illustrate a sample embodiment of a patient interface structure according to sample embodiments; Fig. 17h and 17i schematically illustrate a swivel seal ring according to a sample embodiment in connection with a patient interface structure ing to a sample embodiment; Fig. 17j schematically illustrates a patient interface system according to a sample embodiment including an air delivery tube, an elbow, a swivel seal ring, and a patient ace structure; Fig. 17k schematically illustrate a seal formed between an elbow and a swivel seal ring according to a sample embodiment; Fig. 17l schematically illustrates a seal ring according to another sample embodiment; Fig. 17m tically illustrates a seal ring according to another sample embodiment; James & Wells Ref: 504864DIV6 Figs. 17n and 17o schematically rate a swivel seal ring according to another sample embodiment; Figs. 18a – 18c schematically illustrate a connection of the patient interface structure to the seal positioning and stabilizing ure according to one sample embodiment; Figs. 18d – 18q tically illustrate a connection of the patient interface structure to the seal positioning and stabilizing ure according to other sample embodiments; Figs. 18r and 18s schematically illustrate cross ns of a patient interface structure according to a sample embodiment; Figs. 19a – 19e schematically illustrate a ladder lock connector according to a sample embodiment; Figs. 20a and 20b schematically illustrate a seal positioning and stabilizing structure strap connector according to a sample embodiment; Figs. 21a and 21b schematically illustrate another sample embodiment of a seal positioning and stabilizing structure strap tor; Figs. 22a and 22b schematically illustrate a sample embodiment of a seal positioning and stabilizing structure strap connector; Figs. 23a – 23c tically illustrate a seal positioning and stabilizing structure strap connector according to another sample ment; Figs. 24a – 241 schematically rate a seal positioning and stabilizing structure comprising connectors according to another sample embodiment; Figs. 24m – 24q schematically illustrate a t interface system according to a sample embodiment including the seal positioning and stabilizing structure of Figs. 24a – 24l; Fig. 24r schematically illustrates a strap connector according to another sample embodiment; Figs. 25a – 25f schematically illustrate seal positioning and stabilizing structure connectors according to other sample embodiments; James & Wells Ref: 504864DIV6 Figs. 26a and 26b schematically illustrate nasal pillows according to a sample embodiment; Figs. 27a and 27b schematically illustrate a nasal pillow according to another sample ment; Figs. 28a and 28b schematically illustrate a nasal pillow according to another sample embodiment; Figs. 29a and 29b schematically illustrate a nasal pillow according to another sample ment; Figs. 30a and 30b schematically illustrate a nasal pillow according to another sample embodiment; Figs. 31a and 31b schematically illustrate a nasal pillow ing to another sample embodiment; Figs. 32a – 32f schematically illustrate a nasal pillow according to another sample embodiment; Figs. 33a and 33b schematically illustrate a nasal pillow according to another sample ment; Fig. 34 schematically rates nasal pillows according to r sample embodiment; Fig. 35 schematically illustrates a nasal pillow according to another sample embodiment; Figs. 36 schematically illustrates a nasal pillow according to another sample embodiment; Fig. 37 schematically illustrates a nasal pillow according to yet r sample embodiment; Figs. 38a and 38b schematically illustrates a nasal pillow according to another sample embodiment; James & Wells Ref: 504864DIV6 Figs. 39a – 39h schematically illustrate nasal pillows according to other sample embodiments; Fig. 40 schematically illustrates a nasal pillow configuration according to another sample embodiment; Fig. 41 schematically illustrate a nasal pillow according to another sample embodiment; Figs. 42a – 42c schematically illustrate a patient interface system ing to a sample embodiment in various stages of sealing engagement with a patient; Figs. 43a – 43c schematically rate a patient interface system according to a sample embodiment in various stages of g engagement with a patient; Figs. 44a and 44b schematically illustrate a patient interface system according to a sample embodiment; Figs. 45a – 45e schematically illustrate a patient interface system according to a sample embodiment; Figs. 46a and 46b schematically illustrate straps of seal oning and stabilizing structures according to sample embodiments; and ] Figs. 47a and 47b tically illustrate a patient interface system according to a sample embodiment.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS The following description is provided in relation to several embodiments which may share common characteristics and features. It is to be understood that one or more features of any one embodiment may be combinable with one or more features of the other embodiments. In addition, any single feature or ation of features in any of the embodiments may constitute additional embodiments.

In this specification, the word ising" is to be understood in its "open" sense, James & Wells Ref: 504864DIV6 that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of". A corresponding g is to be attributed to the corresponding words "comprise," "comprised" and "comprises" where they appear.

The term "air" will be taken to include breathable gases, for example air with supplemental oxygen. It is also acknowledged that blowers or flow generators described herein may be designed to pump fluids other than air. The term "rigid" will be taken to mean not y deforming to finger pressure, and/or the tensions or loads typically tered when g up and maintaining a patient interface in sealing relationship with an entrance to a patient’s airways. The term "semi-rigid" means being sufficiently rigid to not substantially distort under the effects of tube drag. 3 PATIENT INTERFACE SYSTEMS 3.1 Introduction Fig. 3a schematically illustrates an aspect of the present technology whereby headgear tension is directed close to the base of the nose and ially disruptive effects of tube drag are isolated or decoupled from the seal. See also Fig. 4. By way of contrast, refer to Fig. 1 where ar structure attempts to stabilize a frame at a point spaced from the g surface (the base of the nose) and y the tube is directly coupled to the headgear via the rigid frame.

Referring to Fig. 3a, a patient interface system according to a sample embodiment may comprise a patient interface structure 32 configured to sealingly engage the airways of the patient 1. The patient interface structure 32 may comprise a seal, for example, nasal pillows or nasal prongs, to gly engage the patient’s airways. As used herein, the term "nasal pillow" refers to a -like structure that is configured to be inserted at least partly into the nasal passageway of the patient and form a seal against an outer surface of the t’s nare.

Nasal pillows in accordance with the present technology include: a frusto-cone, at least a portion of which forms a seal on an ide of the patient's nose; a stalk, a flexible region on the underside of the cone and connecting the cone to the stalk. In addition, the structure to which James & Wells Ref: 504864DIV6 the nasal pillow of the present technology is ted includes a flexible region nt the base of the stalk. The le regions can act in t to tate a universal joint structure that is accommodating of relative movement- both displacement and angular- of the frusto-cone and the structure to which the nasal pillow is connected. For example, the frusto-cone may be axially displaced towards the structure to which the stalk is connected.

A related pillow in accordance with the present technology is described in WO 2006/130903 A1, the ts of which are hereby incorporated by reference, for example in paragraphs [00254] and [00255] and Fig. 66c. The term "nasal prong" refers to a nozzle-like structure that is configured to be inserted into the patient’s nasal eway and form a seal with the interior of the patient’s nasal passageway. It should also be appreciated that the patient interface structure 32 may comprise a nasal patient interface structure or a full face patient interface structure, i.e. a structure ured to cover part of, or all of, the patient’s nose and/or mouth and seal against the patient’s face. The patient interface ure may be formed of, for example, silicone, foam, or gel.

The patient interface structure 32 may be connected to an air delivery hose or tube 16 by a decoupling arrangement 34. The decoupling arrangement 34 may include, for example, a flexible portion of the patient interface structure 32, a swivel elbow including, e.g., a ball and socket connection, and/or a swivel seal ring. The air ry hose may be a retractable hose, as disclosed, for example, in U.S. Application 12/211,896, filed September 17, 2008, the entire contents of which are incorporated herein by reference.

] The patient interface system may also comprise a seal positioning and stabilizing structure 36 that is configured to position and stabilize the patient interface structure 32 in sealing engagement with the patient’s s. The seal positioning and stabilizing structure 36 may be flexible. As shown in Fig. 3a, the seal positioning and stabilizing structure is connected to the patient interface structure 32. The seal positioning and stabilizing structure 36 may include a side straps, or members, 38 ured to extend along each side of the patient’s face, only one James & Wells Ref: 504864DIV6 being shown in Fig. 3a, a top strap 40 configured to extend across the top of the patient’s head, and a rear strap 42 configured to extend around the back of the patient’s head.

In use, each side strap 38 of the seal positioning and stabilizing structure 36 may be attached to the patient interface structure 32. For example, a connector may be ed on each side of the patient interface ure 32, one on each side of the nose of the patient 1. It should be appreciated that multiple connectors may be provided to the patient interface structure and in any arrangement, for e two connectors on each side of the nose of the patient. The pair of connectors form a connection between the patient interface structure 36 and the seal positioning and stabilizing ure 36 as described in more detail herein. Th e tion is close to the entrance to the nares of the patient 1. In this way, the straps 38, 40, 42 of the seal positioning and stabilizing structure 36 hold the seal in position against the face of the patient more directly than in prior art arrangements, such as the prior art ement shown in Fig. 1. In the prior art arrangement of Fig. 1, the tion of the seal positioning and stabilizing structure strap to the frame is displaced from the entrance to the patient’s nares and the patient interface structure is held against the face of the t in an indirect manner.

In the arrangement shown in Fig. 3a, the decoupling arrangement 34 is provided between the connection of the straps 38 of the seal positioning and stabilizing structure 36 and the connection with the air delivery tube 16 so that tube drag does not directly impact the seal formed between the patient interface structure 32 and the patient’s airways.

In a typical prior art arrangement, for example the one shown in Fig. 1, the tension of the ar is often set at a level both to form a seal and to overcome tube drag that may occur.

However, according to the sample embodiment shown in Fig. 3a, the tube drag is to some extent decoupled from the seal formed between the patient interface structure 32 and the patient’s airways and the tension provided by the seal oning and stabilizing structure need only be set at a level ary for sealing. Hence, the tension may be set with a lesser regard for overcoming tube drag. The sed tension provides increased patient comfort.

James & Wells Ref: 504864DIV6 As shown in Fig. 3a, the flexible seal positioning and stabilizing structure 36 may be configured so that the force vectors provided by the straps 38, 40, 42 of the seal positioning and stabilizing structure 36 maintain the patient interface structure 32 in sealing engagement with the nares of the t 1. It should be appreciated, however, that other seal positioning and stabilizing structures may be utilized, as described in more detail herein. For exa mple, straps may be routed around and engaged with the ears of the t. According to another sample embodiment , the straps may be eliminated and a nasal clip may be used to hold the seal of the patient interface structure 32 in position.

The seal positioning and izing ure 36 may be formed of a foam and fabric laminated material, such as BREATHOPRENE®. Alternatively, the seal positioning and izing structure 36 may be made from silicone or other polymers. One of the benefits of using silicone or BREATHOPRENE® is there is no difference in temperature of t’s skin when using either silicone or BREATHOPRENE® headgear. However, silicone can or over time (typically oxidizes to yellow). Therefore, it may be ble to add a tint, such as light blue, to the silicone to reduce the visual impact of discoloration. Sharp corners of the headgear may also be rounded to reduce incidences of irritation to the patient’s skin.

The silicone could be polished or matte on both sides or matte on one side and polished on the other – preferably matte on both sides, or matte on the skin contacting side and polished on the outer side. Matte surface finish gives the perception of comfort.

The decoupling arrangement 34 acts as a flexible connection and links the patient ace structure 32 to the air delivery tube 16. According to the sample embodiment shown in Fig. 3a, only the seal of the patient ace structure 32 is held in a set location. There is no shell or frame that needs to be held in a set location. The decoupling arrangement 34 is free to move with the air delivery tube 16, thereby reducing tube drag and increasing the stability of the seal formed between the patient interface structure 32 and the airways of the patient 1.

Use of the seal positioning and stabilizing structure 36 also s rotation of the James & Wells Ref: 504864DIV6 plane of the patient interface structure 32 with respect to the seal positioning and stabilizing structure 36 to odate different abial angles and different positions of the mask in use. For e, the connectors provided on the patient ace structure 32 may include a plurality of connection points to allow the relative position of the patient interface structure 32 with respect to the seal positioning and stabilizing structure 36 to be changed or adjusted. The axis about which rotation may be ed may be defined as being parallel to a line drawn through both eyes of the patient, and being located below the nose of the patient.

] As shown in Fig. 3b, a desirable vector 404 will produce force normal to the nares.

The entire vector 404 pulls the seal, e.g. the pillows, against the nares.

The vectors of the seal positioning and stabilizing structure 36 of the sample ments are configured to force the seal, e.g. the pillows, up against the patient’s nose. The vectors may be modified by the direction of the straps 38, 40, 42. For example, the straps 38 may extend higher on the face (i.e. closer to the eyes than the ears of the patient’s cheek) to increase force in the vertical axis thereby increasing the force up and against the user’s nose.

The shape of the straps 38, 40, 42 may also be configured to provide a desirable vector: According to sample embodiments, an arrangement without a frame requires ation of the pillows using the seal positioning and stabilizing structure alone. The width of the straps may be varied to force the seal to tilt in the direction indicated by the vector 404. The width of the straps may be gradually increased from the cheek region to the nasal region to ize the patient interface structure 32.

Altering the thickness of the straps changes the rigidity and thus force distribution along the straps.

Referring to Figs. 44a and 44b, a patient interface system according to a sample embodiment includes a patient interface ure 32 including a flexible base 6. A seal is supported by the flexible base 6. The t interface structure 32 is configured to be held in sealing engagement with the entrance to the patient’s airways. The patient ace structure 32 James & Wells Ref: 504864DIV6 is held in g engagement with the patient’s face by a seal positioning and stabilizing structure 36 that includes a main strap loop 74 and a rear strap 42. The main strap loop 74 includes a right main strap 74r and a left main strap 74l that are configured to be connected at respective first ends to the patient interface ure 32. The right and left main straps 74r, 74l are configured to be connected to each other at respective second ends, for example by a connector 71, for e a buckle. A rear strap 42 of the seal positioning and izing structure 36 extends around the back of the patient’s head at a position above the patient’s ears and is connected at respective ends to the right and left main straps 74r, 74l at positions between the first and second ends of the straps 74r, 74l.

Referring to Figs. 47a and 47b, a patient interface system according to another sample embodiment includes a patient interface ure 320 including a flexible base. A seal is supported by the flexible base. The patient interface structure 320 is configured to be held in sealing engagement with the entrance to the patient’s airways. The patient interface structure 320 is held in sealing ment with the patient’s face by a seal positioning and stabilizing structure that includes a main strap loop 74 and a rear strap 85 having adjustable ends 85e. The main strap loop 74 includes a right main strap 74r and a left main strap 74l that are ured to be connected at respective first ends to the patient interface structure 320. The right and left main straps 74r, 74l may be connected to each other at respective second ends, for example by a connector, for example a buckle. The rear strap 85 of the seal positioning and stabilizing structure extends around the back of the patient’s head at a on above the patient’s ears and is connected at respective ends to the right and left main straps 74r, 74l at positions between the first and second ends of the straps 74r, 74l.

The right and left main straps 74r, 74l may be formed, for example, from silicone. The silicone may be, for example, translucent or arent. The t interface system is therefore less obtrusive and presents a visually more appealing appearance (e.g. to a patient’s bed partner).

The "take off angle" of the straps 74r, 74l from a connection point provides a more James & Wells Ref: 504864DIV6 direct angle to a base of the patient’s temple and are lly higher up on the patient’s face.

The patient interface structure also conforms, or wraps around, the region of the t’s mouth and provides less interference with the area around the mouth. The seal oning and stabilizing structure also covers less of an extent of the t’s face. 3.2 Patient Interface Structure 3.2.1 Patient Interface Structure Including Nozzle Assembly Seal Referring to Fig. 4, a t interface ure 32 according to a sample embodiment includes a seal 2 configured to sealingly engage the patient’s airways. The seal 2 may comprise a nozzle assembly 3 that may comprise a pair of nasal pillows 4 connected to a base portion 6. The pillows 4 each include a conical portion 8 at least part of which is adapted to form a seal with a nare of the t 1. As discussed above, a portion of each pillow 4 is ured to be inserted into the patient’s nasal passageway, but not to form a seal inside the nasal passageway. The conical portion 8 of the pillow 4 includes a sealing surface, or zone, 8a that is configured to engage the nare of the patient and form a seal. The sealing surface, or zone, 8a may be as disclosed, for example in Fig. 21 of reference. Each nasal pillow 4 also includes a stalk, or neck portion, 10 which connects the nasal pillow 4 to a flexible base 6. The stalk, or neck portion, 10 may have a length of between about 3 mm to about 6 mm.

The flexible base 6 is able to wrap around the ide of the nose in use when under tension, and can accommodate different facial geometries. The flexible base 6 includes a pair of connectors 12 configured for connection to a seal positioning and stabilizing structure. The seal positioning and izing structure connectors 12 are arranged at a top portion 6t of the flexible base 6, generally in the same plane as the base of the stalks of the nasal pillows 4. As used herein, the term "top portion" refers to the portion of the flexible base that is adjacent to the seal of the patient interface structure. When viewed from the side (for e in Figs. 17g and 17h) an axis through the stalks of the pillows is generally parallel to a normal to the aperture 324 James & Wells Ref: 504864DIV6 wherethough a supply of air is delivered. This arrangement facilitates a generally narrower patient interface ure than for example the ResMed SWIFT® I (see for example Fig. 76A of to a wider overall mask structure, and hence a patient interface structure in accordance with the present technology is more amenable to side-sleeping by a patient. Other patient interface ures, such as in the Fisher & Paykel OPUS™ and OPUS™ 360, include air delivery at an obtuse angle with respect to the angle of the axis of the nasal pillow when viewed from a ponding orientation to Figs. 17g and 17h. This approach may lead to a greater bulk of structure.

Tension 14 is d to t interface structure 32 by the seal positioning and izing ure to hold the nasal pillows 4 of the seal 2 in sealing engagement with the nares of the patient 1. A lower portion 6l of the flexible base 6 forms part of a decoupling arrangement. For example, the lower portion 6l of the flexible base 6 may comprise a gusset, such as the gusset disclosed in WO 01/97893 A1, which is incorporated herein by reference. As used herein, the term "lower portion" refers to the portion of the flexible base that is configured to be connected to an air delivery tube or hose, or to a frame or shell. The lower portion 6l may define a plenum with flexible side walls. The plenum is flexible, but not so limp or floppy that it cannot support its own weight. In other words, the plenum is capable of holding its shape before pressurization by the flow of breathable gas. In this sense, the plenum may be described as semirigid.

The plenum may have flexible bellows-like structure on left- and right-hand sides, and narrowed portions adjacent the top lip and underside of nose to avoid contact ith in use.

See for example Fig. 17a where the end of line 329 is located in a flexible bellows-like region 339 and the end of arrow 320 is adjacent a narrowed region 321, as also shown in Fig. 18r. See also Fig. 17d where T4 tes a thickness suitable to provide the flexibility rated in Figs. 42a - 42c and Figs. 43a - 43c. The flexibility of the plenum is facilitated by manufacture in a James & Wells Ref: 504864DIV6 material such as silicone with a Shore A durometer in the range of about 20 to about 60, more preferably about 30 to about 50, most preferably about 40. A harder ne may use thinner walls, a softer silicone may use thicker walls. A rounded bellows-like structure also tates flexibility independent of the material it is constructed from. Another plenum may be molded from polyurethane foam. Prior patient interfaces such as the Fisher & Paykel INFINITY™ 481, OPUS™, OPUS™ 360, and the Respironics OPTILIFE™ include a range of rigid materials such as polycarbonate. Other masks such as the AIRSEP™ Ultimate mask include rigid headgear tors.

The t interface ure 32 may be formed in one piece, for example by molding a material such as silicone. In one form of the sample embodiment, the range of movement provided by the flexibility of the pillows 4 with respect to the top portion 6t of the le base 6 may be relatively small compared with the range of movement ed by the lower part 6l of the flexible base 6 acting as part of the ling arrangement.

In use, a strap of the seal positioning and stabilizing structure is attached to each seal positioning and stabilizing ure connector 12, one on each side of the nose of the patient, for example as shown in Fig. 3, establishing a connection. The connection is close to the plane of the entrance to the nares of the patient. In this way, the straps of the seal positioning and stabilizing structure 36 more directly hold the nasal s 4 in position than in prior art arrangements, such as shown in Fig. 1, where the connection is displaced from the plane of the entrance to the nares of the patient. Other prior art patient interfaces such as the Fisher & Paykel INFINITY™ 481, OPUS™, OPUS™ 360, and the Respironics OPTILIFE™ place the point of connection at some distance from the nares. The lower portion 6l of the flexible base 6 acts as part of a decoupling arrangement between the plane of connection with the straps of the seal positioning and stabilizing structure 36 and the connection with the air delivery tube 16 so that tube drag does not directly impact the seal formed between the nasal pillows 4 and the nares of the patient.

James & Wells Ref: 504864DIV6 Referring to Figs. 8b and 8n, a patient interface ure 32 according to another sample embodiment may comprise a seal 2 comprising a nozzle assembly 3 having a pair of nasal pillows 4. The flexible base 6 may include ally formed connectors 50. The patient ace structure 32 may be coupled to a decoupling arrangement, e.g. a swivel ring, to decouple tube drag forces as will be described in more detail.

Each nasal pillow 4 may include a conical portion 8 and a neck portion 10. Each conical portion 8 may comprise a sealing zone 8a configured to form a seal against the patient’s nare. The nasal pillows 4 may be formed with the patient interface structure 32 or may be removably attached to the patient interface structure 32, for example as described in WO 2005/063328, the entire contents of which are incorporated by reference. The patient interface structure 32 may further comprise an aperture 46 for introduction of a flow of breathable gas into the patient interface structure 32. The aperture 46 may be formed in a lower portion 61 of le base 6 and be surrounded by a flange 48 that is configured for engagement with an air delivery tube, or a swivel elbow assembly, or a ball and socket joint. It should also be appreciated that the flange 48 of the patient interface structure 32 may be configured for connection to a frame or shell.

The patient interface ure 32 may be formed of a flexible al, such as silicone. The patient interface structure 32 may be formed of one piece, including the nasal pillows 4, the flange 48, and a pair of tors 50 provided at each end of the patient ace structure 32. As shown in Fig. 8b, each connector 50 may comprise a first slot 52 and a second slot 54 for receipt of an end of a strap of the seal positioning and stabilizing ure. The first slot 52 and a second slot 54 are separated by a crosspiece 56 which may engage the end of the strap to retain the end of the strap in contact with the connector 50. The patient interface ure, including the connectors 50, is flexible and forces applied by the seal positioning and stabilizing structure, for example by side straps, stretch the connector 50 to increase the force that the crosspiece 56 exerts on the seal positioning and stabilizing structure strap.

James & Wells Ref: 504864DIV6 The patient interface structure 32, including the connectors 50, may be integrally formed, for example by molding. The patient interface structure 32 may be formed so as to have varying densities and/or hardnesses. For example, the nasal pillows 4 and/or the le base 6 may be formed of a first y and/or hardness and the connectors 50 may be formed of a second density and/or hardness. The second density and/or hardness may be higher than the first y and/or hardness. This permits the patient interface structure 32 to be formed so as to have a softer feeling in those areas that engage the t’s face (e.g. the nozzle assembly of the seal) and a harder, or more rigid, feeling in the area connected to the seal positioning and stabilizing structure. The hardness, e.g. durometer, of the patient interface structure may be different from the hardness of the seal positioning and stabilizing structure discussed below. For example, the durometer of the connectors and/or le base of the patient interface structure may be different from the straps and/or the connectors of the straps of the seal positioning and stabilizing ure. 3.2.2 Patient Interface ure Including Nasal Prongs as Seal Figs. 5a and 6 illustrate an aspect of the present technology whereby the point of connection of the seal positioning and stabilizing structure is moved closer to the base of the seal, for example close to the base of nasal pillows or prongs. Referring to Fig. 5a, a patient interface system according to a sample embodiment includes a patient ace structure 32a comprising a seal 2a including a nozzle assembly 3a. The nozzle ly 3a comprises a pair of nasal prongs 4a. Each nasal prong 4a includes a stalk, or neck portion, 10a that connects the nasal prong 4a to a flexible base 6a of the patient interface structure 32a. Flaps 4b are provided between the nasal prongs 4a and the stalks 10a. The nasal prongs 4a form a seal with the nasal passageways of the patient when the nozzle assembly 2a is held by a seal positioning and stabilizing structure in engagement with the face of the t.

A pair of seal positioning and stabilizing structure connectors 12a are provided on a flexible base 6a of the patient ace structure 32a. tors 12a are provided on the James & Wells Ref: 504864DIV6 flexible base 6a for the connection of straps of a seal positioning and stabilizing structure with the patient interface structure 32a.

The tors 12a may include a plurality of connection points 13a, 13b to allow the relative position of the patient interface structure 32a with respect to the seal positioning and stabilizing ure 36 to be changed or adjusted. ing again to Fig. 2, a patient interface system may include the patient interface structure of Fig. 5a and a mask shell or frame as shown in Fig. 2 that is modified to not include the connectors on the frame and includes a vent having a plurality of vent holes. The mask frame may be connected to an air delivery tube by a swivel elbow. The ends of the swivel elbow may e ball and socket type connections to the frame and the air delivery tube so that the swivel elbow acts as a decoupling element or joint. The delivery tube may receive a flow of pressurized breathable gas by being connected through a coupling element to a flow generator or blower. It should be appreciated that the mask frame of Fig. 2 may be formed of a flexible material, instead of a rigid material as in the prior art shown in Fig. 2, and the connectors 12 may be provided on the flexible frame.

In another sample embodiment, the elbow may be flexible. In such a form, it may be desirable to locate the vent holes elsewhere on the mask system. Alternatively, a solid vent insert may be placed in the flexible elbow. In another form, reinforcement may be provided to the le elbow to maintain its structural integrity and prevent the tube from occluding. 3.2.3 t Interface Structure Including Nasal Prongs Seal and Connectors on Nasal Prongs ing to Fig. 6, in another sample embodiment , the seal positioning and stabilizing structure connectors 12a are provided at a point just below the flaps 4b of the nasal prongs 4a. The seal positioning and stabilizing structure tors 12a are connected to the neck, or base, portions 10a of the nasal prongs 4a. ing to this embodiment, the plane of connection formed by the seal positioning and stabilizing ure connectors 12a is closer to the James & Wells Ref: 504864DIV6 plane of the entrance to the nares of the patient than the embodiment shown in Fig. 5a. The patient ace structure of Fig. 6 may also be used with a mask frame such as shown in Fig. 2 that is modified to not include connectors on the frame. It should also be appreciated that the patient interface structure of Fig. 6 may be used with a mask frame such as shown in Fig. 2 that is modified to be formed of flexible material. 3.2.4.1 Patient Interface Structure Including Linking Element - First Embodiment Referring to Figs. 8a and 8b, a patient interface structure according 32 according to another sample embodiment may comprise a seal 2 sing a nozzle ly 3 having nasal pillows 4. The patient interface structure 32 may include an optional linking portion or t 47 ured to link n forces d by the seal positioning and stabilizing structure from one side of the patient ace structure 32 to the other side in order to isolate forces applied by the seal positioning and stabilizing structure at the top portion 6t of the flexible base 6, and thereby e tube drag forces at the lower portion 61 of the flexible base 6 of the patient interface structure 32. By ing forces in such a way, the sealing zones 8a of the nasal pillows 4 of the seal 2 are stabilized against the patient’s nares in use. In some forms of the technology, there may be no physical linking element. The line of force defined by the linking element is preferably close to the base of the nose when used in an under-the-nose type mask such as nasal pillows or nasal prongs.

As shown in Fig. 8a, the linking element 47 may take the form of a stiffened and/or reinforced top portion 6t when compared to the lower portion 6l of the flexible base 6. The lower portion 6l may include, or take the form of, a gusset, for example as disclosed in WO 01/97893.

The gusset may also be configured similarly to an accordion, having multiple ridges to increase its springiness and flexibility, for example as disclosed in of which are incorporated herein by reference.

The gusset may also be reinforced to control where and how it collapses, i.e. so that it can move laterally and axially but cannot ss ally. Reinforcement may include James & Wells Ref: 504864DIV6 supporting ribs, thickened sections or regions, or a rigid or semi-rigid skeleton with a flexible material surrounding it.

] Stiffening and/or reinforcing may be achieved by a thickening of the material used in the t interface structure 32, for example increasing the thickness of the silicone by up to about 10 mm at the top portion 6t when ed to the lower portion 6l of the flexible base 6.

Such stiffening and/or reinforcing may also be achieved through the use of a higher hardness material positioned at the top portion 6t, for e silicone of a durometer between about 50 – 80 on the Shore A hardness scale. Additionally, or alternatively, metal inserts, for example a wire(s) or mesh(es), may be used in the g element 47. Stiffening and/or reinforcing may also be achieved by a gel insert. The gel insert may also increase patient comfort, for example at the septum. Furthermore, stiffening and/or reinforcing may also be achieved by a foam insert.

The foam insert may increase patient comfort, for example at the septum, and act as a secondary seal should a leak form at the primary seal. The linking element 47 may also be formed of a comolded , generally nsible material, for example nylon, TPE, metal, or alloy. The linking t 47 may also be in the form of a beaded, thickened portion, as described in more detail below. bly, stiffening and/or reinforcing the top portion 6t, for example to form the g element 47, will result in the lower portion 6l being more extensible so that forces applied by the seal positioning and stabilizing structure are more isolated from the lower portion 6l. This allows the lower n 6l of the flexible base 6, for example the gusset, to flex more easily while ensuring that the nasal pillows 4 are held in sealing contact with the nares of the patient.

In another form, the linking element 47 may be configured in such a way that it is stiff along its length, e.g. from connector 50 to connector 50, but elastic through its height, i.e. in the general ion of the nasal s 4. This enables the neck portions 10 of the nasal pillows 4 to flex more readily while maintaining the primary function of the linking element 47, i.e. isolating the forces applied by the seal positioning and izing structure.

In a variant, the linking element 47 may be formed from a material that can be molded James & Wells Ref: 504864DIV6 to the patient’s face, for example the plastic al used to form mouth guards. This would provide the t of isolating forces and increasing the comfort of the patient interface system due to its unique fit. 3.2.4.2 Patient Interface Structure Including Linking Element – Second Embodiment As shown in the sample embodiment of the patient interface structure shown in Fig. 8a, the linking t 47 may extend across the entire top portion 6t of the flexible base 6, from tor 50 to tor 50, and including the entire width. See, for example, W1 in Fig. 17a.

According to another sample embodiment of the patient interface structure 32 shown in Fig. 8c, the linking element 47 may extend over a section, or sections, of the top portion 6t of the flexible base 6, for example only the n of the top portion 6t between the nasal pillows 4. The linking element 47 may cover a fraction of the width of the top n 6t, for example half the width. The tension linking element 47 may cover a section, or sections, of the top portion 6t as long as it is sufficient to isolate the forces as described above. 3.2.4.3 Patient Interface Structure Including Linking Element - Third Embodiment Referring to Fig. 8d, the linking element may be formed as a series of ridges 47a. The number of ridges 47a may be determined in order to sufficiently isolate forces as described above. As shown in Fig. 8d, the ridges 47a may be provided to the top portion 6t only between the nasal pillows 4. The ridges 47a may be thicker than the top portion 6t. The ridges 47a may be generally ar or rectangular or any other shape. The ridges 47a may extend upwards and/or downwards from the top n 6t. The ridges 47a may also be formed from a material of higher hardness than that used to form top portion 6t, for example higher durometer silicone, or metal. The ridges 47a may be formed in one piece with the patient interface structure 32, or may be retrofitted to the patient interface ure 32. For e, the linking element, e.g. the ridges 47a, may be adhesively attached to the patient interface structur32. The ridges 47a may also be independent of one another, or the ridges 47a may be joined together. In the case of the James & Wells Ref: 504864DIV6 linking ts comprising inserts, the inserts may be separately provided, or connected together. The ridges 47a may also be formed of individual shapes, sizes, thicknesses, materials, and/or hardnesses. 3.2.4.4 Patient Interface ure Including g Element - Fourth Embodiment Referring to Fig. 8e, the ridges 47a may be provided to the top portion 6t along the entire length of the flexible base 6, i.e. from connector 50 to tor 50. 3.2.4.5 t Interface Structure ing g Element - Fifth Embodiment Referring to Fig. 8f, the linking element 47 may be formed in the top n 6t of the flexible base 6 of the patient interface structure 32. For example, the patient interface structure 32 may be molded around the linking element 47 so that the linking element 47 is embedded within the top portion 6t of the flexible base portion 6 of the patient interface structure 32. The linking element 47 may be , for example, of metal or plastic material. The linking element may also be in the form of, for example, a wire or a mesh. 6 Patient Interface Structure Including Linking Element - Sixth Embodiment ] Referring to Figs. 8g and 8h, according to another sample embodiment, the linking element 47 may be provided along the top portion 6t of the flexible base 6. The linking element 47 may include slots or openings 47o that correspond with the first and second slots 52, 54 of the connector 50 to accept the straps of the seal positioning and stabilizing structure that connect to the patient interface structure 32. As shown in Fig. 8h, the linking element 47 may have an e that matches the top portion 6t of the flexible base 6 of the patient interface structure 32 and comprise openings 47p that are configured to receive the stalks or neck portions 10 of the pillows 4. The linking element 47 may also include slits 47s that allow the portions of the linking element 47 around the openings 47p to be displaced with respect to one another to insert the linking element 47 over the pillows 4 and onto the top portion 6t of the flexible base 6.

] The t 47 may be formed of, for example, metal or plastic. For example, the linking element 47 may be a thin metal sheet that is stamped into the configuration shown in Fig.

James & Wells Ref: 504864DIV6 8h. It should also be appreciated that the connectors 50 of the patient interface structure 32 may be ated and the straps of the seal positioning and stabilizing structure connected directly to the g element 47 without any direct connection to the patient interface structure 32. 3.2.4.7 Patient Interface Structure Including Linking Element – Seventh Embodiment Referring to Figs. 8i and 8j, a linking t 47 may extend around the neck ns of the pillows 4. As shown in Fig. 8j, the linking element 47 may have a figure eight configuration and e openings 47p that are configured to receive the neck portions 10 of the pillows 4. The linking element 47 may be formed from, for example, metal or plastic. For example, the linking element 47 may be formed from a wire. 3.2.4.8 t Interface Structure Including Linking Element - Eighth Embodiment Referring to Fig. 8k, according to another sample embodiment, the linking element 47 may comprise a bridging portion between the stalks or neck ns 10 of the nasal s 4.

The linking element 47 may be integrally formed, e.g. by molding, with the patient interface ure 32. The linking element 47 may also be formed of a different al than the material used to form the patient interface structure 32. For example, the linking element 47 may be formed of a higher durometer material than the patient interface structure material. The linking element 47 may be formed to be more rigid than the top portion 6t of the flexible base 6 of the patient interface structure 32. 3.2.5 Nasal Pillow Seals - Offset Referring to Figs. 27a and 27b, each nasal pillow 4 may comprise a pillow orifice 5 for delivering breathable gas to the nares of the patient. Each pillow 4 is inserted into a nare of the patient and is sealed at a g surface 11. As shown in Fig. 27b, the pillow orifice 5 is offset from a neck orifice 9 of the stalk or neck portion 10 along a major axis 13 of the elliptically shaped nasal pillow 4 by shifting the pillow orifice 5 along the major axis 13. The portion 11a of the sealing surface 11 that is in t with the upper lip of the patient is thus reduced, which James & Wells Ref: 504864DIV6 may increase patient comfort. Although the pillow orifice 5 is shown shifted from the neck orifice 9 along the major axis 13, it should be appreciated that the pillow orifice 5 may be d along the major axis 13 and/or the minor axis 15. 3.2.6 Nasal Pillows Seal Including Dual Walls Referring to Figs. 17a – 17f, a patient interface structure 320 includes connectors 322 on each side and connected to a flexible base 329 of the patient interface structure 320 by extensions 323. It should be appreciated that the connectors 322 may be ted by the extensions 323 to respective neck portions 332 of a pair of nozzles 328 in a manner similar to that discussed above with respect to Fig. 6. The connectors 322 may be linear with the upper surface of the le base 329 (as shown in Figs. 17b and 17d). Alternatively, the connectors 322 may be tilted or angled to alter the position of the patient interface structure 320 when connected to the seal positioning and stabilizing structure.

The patient interface structure 320 comprises a seal 333 comprising a nozzle assembly comprising the pair of s taking the form of nasal pillows 328. As shown in Figs. 17b and 17d, the pillows 328 each comprise a neck portion 332 that is connected to the flexible base 329 that defines a nasal breathing cavity 336. As also shown in Figs. 17d and 17e, each nasal pillow 328 comprises an inner l portion 334 and an outer conical portion 330. Such pillows are disclosed, for example, U.S. Patent Application Publications 2007/0144525 A1 and 2006/0283461 A1, the entire contents of each being incorporated herein by reference. It should also be appreciated that the nasal pillows may be as described in, for e, U.S. Patent 7,318,437, the entire contents of which are orated herein by reference. The outer conical portion 330 ses a sealing surface, or zone, 330a that is configured to seal against the patient’s nare. As shown in Fig. 17d, the inner conical n 334 and the outer conical n 330 may have different thicknesses.

Referring to Figs. 17d, 17f and 17g, the flexible base 329 includes an aperture 324 for the introduction of the flow of breathable gas. The flexible base 329 r comprises a flange James & Wells Ref: 504864DIV6 326 that extends radially inwardly and defines the aperture 324. The flange 326 may comprise a chamfer 327 for insertion of a swivel sealing ring as discussed in more detail below. The flexible base 329 of the patient ace structure 320 may thus be connected to a frame, a swivel elbow, or a tube or conduit as also described in more detail below.

It should also be appreciated that the flexible base 329 may include a linking element(s), similar to the one disclosed and discussed with respect to Figs. 8a – 8g,for example in between the neck portions 332 of the nasal pillows 328.

] Referring to Fig. 17a, the aperture 324 may have a diameter D1 of about 17 mm – 20 mm, for example about 18.5 mm. The patient ace structure 320 may have a width W1 of about 25 mm – 35 mm, for e about 30.5 mm. The patient interface structure 320 may have a length L1 of about 80 mm – 90 mm, for example about 84.5 mm. The seal oning and stabilizing structure connector 322 may have a length of about 12 mm – 18 mm, for example about 15.5 mm.

Referring to Fig. 17d, the flexible base 329 may have a length L3 of about 45 mm – 50 mm, for example about 47.5 mm. The patient ace structure 320 may be a height H1 of about 30 mm - 37 mm, for example about 33 mm. The base portion 329 may have a height H2 of about 15 mm – 23 mm, for example about 19 mm. ing to Figs. 17d and 17g, the extensions 323 may have a ess T1 of about 1.5 mm – 2.0 mm, for example about 1.8 mm. The flexible base 329 may have a thickness T2 between the nasal pillows 328 of about 1.5 mm – 2.5 mm, for example about 2.0 mm. It should be appreciated that the thickness T2 may be greater, for example in the case where a linking element is formed in one piece with the patient interface structure 320 between the nasal pillows 328. The flange 326 may have a thickness T3 of about 1.5 mm – 2.5 mm, for example about 2.0 mm. The flexible base 329 may have a thickness T4 of about 0.6 mm – 1.0 mm, for example about 0.8 mm.

The stalks 32 may have a length of about, for example, 3 mm to about 6 mm.

James & Wells Ref: 504864DIV6 3.2.6.1 Nasal Pillows Seal Including Dual Walls – Equal Displacement and Non- Concentric Referring to Figs. 28a and 28b, the pillows 328 may comprise the outer conical portion 330 and the inner conical n 334. A portion 360a of a sealing zone 360 of the outer conical portion 330 that is in contact with the upper lip of the patient is ced an equal ce 362 from the stalk or neck portion 332 of the pillow 328 as a portion 360b of the sealing zone 360 that is in sealing engagement with the nares of the patient. The sealing zone 360 and the pillow orifice 354 are non-concentric with the stalk 332 of the pillow 328. 3.2.6.2 Nasal Pillows Seal Including Dual Walls – Unequal Displacement and Concentric Referring to Figs. 29a and 29b, the portion 360a of the g zone 360 that engages the upper lip of the patient is displaced a distance 364 that is not equal to the distance 366 that the portion 360b is displaced from the stalk 332. The pillow orifice 354 and the sealing zone 360 are tric with the stalk 332. 3.2.6.3 Nasal Pillows Seal Including Dual Walls – Unequal Displacement and Concentric with Supporting Rib Referring to Figs. 30a and 30b, the portion 360a is displaced an unequal amount from the stalk 332 than the sealing zone n 360b. The sealing zone 360 and the pillow orifice 354 are concentric with the stalk 332. A supporting rib 368 may be provided under the portion 360b of the sealing zone 360 to maintain the pillow sealing zone in an upright position so that it may seal at the nares. 3.2.6.4 Nasal Pillows Seal Including Dual Walls – Concentric and Angled As shown in Figs. 31a and 31b, the inner conical portion 334 and the outer conical portion 330 are tilted at an angle 370 with respect to the stalk 332 of the pillow 328. The angle tilts the pillow towards the face of the patient and may be, for e, -30˚ to 45˚, as another example 15˚. The portion 360a configured to engage the upper lip of the patient has a larger radius than the sealing zone portion 360b to provide for greater t comfort. The pillow James & Wells Ref: 504864DIV6 orifice 354 and the sealing zone 360 are eccentric with respect to the stalk 332.

Nasal Pillows Seal Including Dual Walls – Symmetrical, tric and Angled Referring to Figs. 32a – 32f, the orifice of the inner l surface1100, the outer 1000 walls and stalk 1200 of the nasal pillow 1150 are concentric with t to a center line CL. The radius of the portion 1600 on the opposite side to portion 1500 is smaller than the radius of the portion 1500 that is adjacent to the upper lip of the patient. The larger radius of portion 1500 has a thickened region 1550 that assists in avoiding t between the nasal pillow and the top lip, pushing the structure away therefrom. Avoiding contact with the top lip can improve comfort for some ts. An advantage of this is that the need to provide a separate manual pillows rotation mechanism may be reduced since the pillow may automatically move away from the top lip, adjusting to the naso-labial angle of the patient. This may in part be assisted by flexure of the t interface structure connectors 84 of the seal positioning and stabilizing structure.

The base of the pillow 1150 is angled with respect to the top of a linking element 1400. The angle α allows the linking element 1400 to tilt. Referring to Fig. 32d, to engage the pillows 1150 with and entrance to the patient’s airways, the pillows are placed at the entry to the nares. As shown in Fig. 32e, as the seal positioning and stabilizing structure is adjusted, strap tension begins to pull the s into the nares. Continued insertion of the pillows into the nares causes the stalk 1200 to collapse into the linking element 1400 via trampoline 1300, moving the linking element 1400 into contact with base of pillows 1150.

The thickened region 1550 results in a relatively stiffer spring structure than the r portion 1600 that may rotate the patient ace structure away from the top lip. Since the base of the pillow 1150 is angled  with respect to the linking element 1400, the linking element 1400 aligns with the base of the pillow 1150 so that they are flush or in constant contact along the whole surface of the base of the pillows 1150. This means that the linking element James & Wells Ref: 504864DIV6 1400 and adjacent trampoline 1300 rotates upwards, i.e. rotates by α° s the top of the patient’s nose. The linking element 1400 and the trampoline 1300 are thereby angled away from the bottom of the pillows or upper lip of the patient. This improves the comfort and stability of the patient interface system.

The rotation of the trampoline 1300 and the linking element 1400 away from the patient’s upper lip could similarly be achieved by skewing the shape of the trampoline 1300 and/or linking element 1400 (e.g. by ng the dimensions of the flexible base of the patient interface ure), change the trampoline properties so that it is stiffer in some regions ed to other regions to force the stalk to collapse in a certain way (e.g. stiffer towards the bottom of the pillows/upper lip side) or changing the ties of the stalk to cause it to collapse more in one direction than another (e.g. stiffer towards the bottom of the pillows/upper lip side). 3.2.6.6 Nasal Pillows Seal Including Dual Walls - Offset Inner and Outer Conical Portions Referring to Figs. 33a and 33b, the nasal pillows 328 may se elliptical inner and outer conical portions 334, 330, respectively. As shown in Figs. 33a and 33b, the orifices 354, 355 of the inner and outer l portions 334, 330, respectively, may be offset along a major axis of the ellipses. The radius of the portion 360a of the sealing zone 360 configured to engage the upper lip of the patient is larger than the radius of the portion 360b configured to seal the nare of the patient. 3.2.7 Nasal Pillows Seal - Truncated Referring to Fig. 34, the s 328 may be ed with cut outs, or truncated portions, 350 for improved upper lip comfort of the patient. As shown in Fig. 35, according to one variant, the pillow orifice 354, the sealing zone 360, and the stalk 332 are concentric. The upper lip contacting side of the pillow 328 includes a truncated portion 350 to t interference and discomfort.

As shown in another variant illustrated in Fig. 36, the pillow orifice 354 and the James & Wells Ref: 504864DIV6 sealing zone 360 are concentric along the centerline 358. The stalk 332 is not concentric with the centerline 358 so that the stalk e 356 is offset from the pillow orifice 354. As shown in Fig. 36, the stalk 332 may be offset in a direction away from the truncated n 350. In a further variant shown in Fig. 37, the stalk 332 may be offset in a direction towards the truncated portion 3.2.8 Nasal Pillows Seal – Coincident Sealing Surface and Stalk As shown in Figs. 38a and 38b, the stalk 332 may be provided at a position coincident with the portion 360b of the sealing zone 360 that is configured to engage the patient’s upper lip. 3.2.9 Nasal s Seal – Bent Stalk and/or g Surface Referring to Figs. 39a – 39h, the outer conical portion 330 of the pillow 328 may be ed at an angle with respect to the stalk 332 and/or the stalk may be angled and/or have a variable cross section. 3.2.10 Nasal Pillows Seal – Rose Bud As shown in Fig. 40, the nasal pillows 328 may be conjoined. The ns 360a of the sealing zones configured to contact the patient’s upper lip may have a shallow radius and the portions 360b configured to engage the nares may have a large radius at the outer edges of the sealing zones to increase the fit range of the pillows. The pillows 328 may have a generally rose bud shaped configuration, as shown in the drawings. 3.2.11 Nasal Pillows Seal – Olive Referring to Fig. 41, the sealing zone of the pillow may have a large radii on either side, or both sides. The pillow may act as a nasal dilator. As shown in the drawings, the pillows 328 may have a generally olive shaped uration. 3.2.12 Patient Interface Structure Including Foam Seal Referring to Figs. 45a – 45e, a patient interface system according to another sample embodiment includes a patient interface structure 32 that es a flexible base 6. A seal 2 is provided on the flexible base 6. The seal 2 may be formed of foam. A swivel elbow 17 is James & Wells Ref: 504864DIV6 connected to the flexible base 6 for ry of a flow of breathable gas from a hose or tube or t (not shown) connected to the swivel elbow 17 into a nasal breathing cavity defined by the flexible base 6 and the seal 2.

The patient interface structure 32 is held in sealing engagement with the t’s face by a seal oning and stabilizing structure 36 that comprises side straps 38, a top strap 40 (Fig. 45c), and a rear strap (not shown). Although the side straps 38 are shown connected to the flexible base 6 in an integral fashion, it should be appreciated that the side straps 38 may be connected to the flexible base 6 in a manner that allows connecting and disconnecting the side straps 38 from the flexible base 6, for example as discussed in more detail herein. It should also be appreciated that one, or both , side straps 38 may be configured to be connectable and disconnectable from the flexible base 6.

As shown in Fig. 45b, the seal 2 includes an aperture 19 that is ured to surround both nares of the patient. As shown in Fig. 45c, the flexible base 6 is conformable and in use wraps around the nose of the patient 1. As also shown in Figs. 45c – 45e, the seal 2 may be ured to seal in part above the tip of the patient’s nose. 3.3 Seal Positioning and Stabilizing Structure 3.3.1 Seal Positioning and Stabilizing Structure – First Embodiment Referring again to Figs. 7a – 7c, the seal positioning and stabilizing structure 36 may be , for example, from a flat silicone sheet. Typically, a headgear for a respiratory mask is formed from a foam and fabric laminate, such as BREATHOPRENE®. Such ar is die cut and thus has squared edges. This can appear bulky on the face of the patient and can be uncomfortable due to its edges. In the sample embodiments disclosed herein, seal positioning and stabilizing structure made from silicone may be molded to have rounded edges. Such rounded edges improve comfort. In one form, the rounded edges may have a radius of greater than about 0.5 mm. As shown in Fig. 7b, the straps 38, 40, 42 of the seal positioning and stabilizing structure 36 may have the rounded edges 420 formed on the patient contacting (i.e.

James & Wells Ref: 504864DIV6 skin contacting) side 418 of the straps 38, 40, 42. The parting line 416 of the tool that forms the straps 38, 40, 42 may be further from the patient contacting side 418 to avoid flash near the patient’s face that can cause irritation. As shown in Fig. 7c, the straps 38, 40, 42 may include a larger radius 422 on the patient contacting side 418 by providing ns 424 on the opposite side that are rolled back from the parting line 416.

Other polymers, e.g. TPE, may be used to form the seal oning and stabilizing structure 36. The seal positioning and stabilizing structure 36 may include two side straps 38 (only one visible in Fig. 7a), a top strap 40, and a rear strap 42. Respective ends 38a of the side straps 38 are connected to connectors 12 (only one visible in Fig. 7a) provided on the flexible base 6 of the patient interface structure 32. The connectors 12 are d on sides of the flexible base 6 to which nasal pillows may be connected. The connection of the connectors 12 to the flexible base 6 enables the flexible base 6 to wrap around the base of the nose of the patient and be pulled back to retain the nasal s in a sealing relationship with the underside of the patient’s nose.

] The respiratory mask system of Fig. 7a may be adjusted by adjusting the connection of the ends 38a of the side straps 38 with the connectors 12. For e, the connectors 12 may each include a slot, or slots, configured to accept the end 38a of the side strap 38. The sealing force provided by the seal positioning and stabilizing structure 36 may be adjusted by adjusting the ends 38a of the side straps 38. For example, to increase the g force d by the seal positioning and stabilizing structure 36, the patient 1 may pull on the end(s) 38a of the side strap(s) 38. The sealing force may be decreased by shortening the end(s) 38a of the side strap(s) 38, e.g. by pulling the side strap(s) 38 back through the connector(s) 12. The patient interface structure 32 may be rotated with respect to the seal positioning and izing structure 36 about an axis generally parallel to a line drawn through both eyes of the patient and below the t’s nose by the inherent flexibility of the straps. It should also be appreciated that inelastic straps may be used. It should be further appreciated that angular adjustment of the patient interface James & Wells Ref: 504864DIV6 ure 32 with respect to the seal positioning and stabilizing structure 36 may be achieved by an adjustment buckle(s)/connector(s), such as those disclosed, for example, in U.S. Patent 6,907,882, the entire contents of which are orated herein by reference. 3.3.2 Seal Positioning and izing Structure – Second Embodiment Referring to Fig. 10, in another sample embodiment , the seal positioning and stabilizing ure 36 may comprise a strap 41 configured to encircle the patient’s head at a position above the patient’s ears. A side seal positioning and izing structure strap 38 (only one visible in Fig. 10) extends along each side of the face of the t 1 and is connected to a respective side of the patient interface structure 32. The patient interface ure may be connected to a swivel elbow or joint 17 through a decoupling arrangement 34, although it should be appreciated that the patient interface structure may be connected to a rigid, or semi-rigid, frame or shell. The swivel elbow is connected to an air ry tube 16 for the delivery of the flow of pressurized breathable gas.

A stiffening, or reinforcing, element 66 may be connected to each side strap 38. As shown in Fig. 10, in order to avoid impingement on the vision of the patient 1, the stiffening or reinforcing element 66 traverses the eye socket of the patient 1. The provision of the stiffening elements thus allows for the force vectors of the seal positioning and stabilizing structure to pass near the eyes of the patient without obscuring the patient's vision. Hence a tension force may be directed in a more ideal direction, orthogonal to the sealing surface, in this case the underside of the patient's nose.

The stiffening element 66 may be ucted from a material sufficiently stiff along the udinal length to resist g under the seal oning and stabilizing structure tension forces, but able to conform in an out of plane direction to lie flat on the patient’s face.

Suitable materials for the stiffening elements 66 include, for example, nylon, polypropylene, and silicone.

The stiffening elements 66 may be threaded through the side straps 38, or the James & Wells Ref: 504864DIV6 stiffening elements 66 may be adhered or stitched in place on the side straps 38. Alternatively, the ning elements may be movable on the side straps 38 of the seal positioning and stabilizing structure 36, for e, by sliding along the side straps 38. 3.3.3. Seal oning and Stabilizing Structure – Third Embodiment Referring to Fig. 11, in another sample embodiment , the top strap 40 may be configured to extend at an angle to the rear strap 42. This configuration produces force vectors that increase the sealing force applied by the seal positioning and stabilizing structure 36 without increasing the tension. A component of the force ed by the top strap 40 is directed upward, which increases the sealing forces applied to the patient interface ure 32. In other words, the sealing force ent of the top strap 40 is added to the sealing force component of the side straps 38 to provide improved sealing without increasing tension. 3.3.4 Seal Positioning and izing Structure – Fourth Embodiment Referring to Figs. 12a and 12b, a patient interface system according to another sample embodiment comprises a seal positioning and izing structure 36 connected to a patient interface structure 32 by lateral side arms 68 provided on each side of the face of the patient 1.

Each lateral side arm 68 may comprise a first side arm connector 68a connected to the patient interface structure and a second side arm connector 68b, with respect to the orientation shown in Fig. 12a, below the first side arm connector 68a, connected to the t interface structure 32.

The lateral side arm 68 may be connected to the rear strap 42 of the seal positioning and stabilizing structure 36 through a slot 68c provided in the lateral side arm 68 that receives the rear strap 42. As shown in Figs. 12a and 12b, a side strap 38 of the seal positioning and stabilizing structure 36 may extend along a portion of the lateral side arm 68. It should be appreciated, however, that the side strap 38 may be eliminated and the lateral side arm 68 may extend from the junction of the top strap 40 and the rear strap 42. Each lateral side arm 68 may be configured to lie on the face of the patient from a point in the l region of the temple to near the base of the patient’s nose.

James & Wells Ref: 504864DIV6 The lateral side arms 68 may be formed of material similar to the stiffening elements described above with nce to Figs. 10 and 11. Alternatively, the lateral side arms 68 may be formed from a soft flexible material, for example a laminate of compressed foam and fabric al, such as BREATHOPRENE®. The lateral side arms 68 may be ucted to be sufficiently stiff along the longitudinal length to avoid bending under the seal positioning and stabilizing structure tension forces, but able to conform in an out of plane direction to lie flat on the patient’s face.

The first and second side arm connectors 68a, 68b are connected to the patient interface structure 32 at two points and are sufficiently wide at the connections to e control over the rotational stability of the seal, but permit rotation of the patient interface 32 to present the seal, e.g. nasal pillows, at a right angle to the sealing surface. 3.3.5 Seal Positioning and Stabilizing Structure – Fifth Embodiment Referring to Figs. 13a and 13b, the lateral side arms 68 may be connected to the side straps 38 through slots 68c. The side straps 38 may be connected to the strap 41 by a strap connector 70. The side strap 38 is connected at one end to the strap tor 70 and at the opposite end to the lateral side arm 68 through the slot 68c. The strap connector 70 may be moved along the strap 41 to allow the t to adjust the position of the lateral side arms 68.

The patient may thus adjust the position of the lateral side arm 68 to effect a good seal n the patient ace structure 32 and the nares of the t, and the patient interface system may be adjustable to fit patients of a variety of sizes. 3.3.6 Seal Positioning and Stabilizing Structure - Sixth Embodiment Referring to Figs. 14a and 14b, according to another sample embodiment , the seal positioning and stabilizing structure 36 may be formed of a single piece, including the top strap 40, the rear strap 42, the side strap 38 and the lateral side arms 68. A buckle 71 may be provided on the top strap 40 to adjust the fit of the seal positioning and stabilizing structure 36 to the patient. It should be iated that the buckle may be provided additionally or alternatively to James & Wells Ref: 504864DIV6 the rear strap 42. The single piece seal positioning and stabilizing structure 36 may be connected to the patient interface structure 32 by tors such as hook and loop fasteners. Alternatively, the single piece seal positioning and stabilizing structure 36 may be a complete circular component that can wrap around the patient ace structure 32 at, for example, the base of the patient ace structure 32 between the patient interface structure 32 and the elbow 17, or at the top of the patient interface ure 32 between the flexible base of the patient interface structure 32 and the seal (e.g. nozzle arrangement). In another sample embodiment, the entire patient interface system, including the t interface ure 32 and the seal positioning and stabilizing structure 36 may be formed as a single component. Additionally, the elbow 17 may also be formed with the patient ace structure 32 and the seal positioning and izing structure 36.

As shown in Figs. 14a and 14b, and Figs. 12a – 13b, the lateral side portions 68 may divide into first and second side arm connectors 68a, 68b to form a triangular cut out proximal to the patient interface structure 32, as shown in the figures. The lengths of the first and second side arm connectors 68a, 68b affect the angle at which the patient interface structure 32 is positioned.

For example, if the first side arm connector 68a is longer than the second side arm connector 68b, the patient interface structure 32 is likely to rotate away from the patient’s nares. Conversely, if the second side arm connector 68b is longer than the first side arm tor 68a, the patient interface structure 32 is likely to rotate towards the patient’s nares. In another sample embodiment, the length of the first side arm connector 68a may be adjustable, y rotating the patient interface structure 32, by an adjustment mechanism, such as a buckle. Similarly, ment may be provided to the second side arm connector 68b to alter its length and thus rotate the patient interface structure, for example by an adjustment ism such as a buckle.

Adjustment may also be provided to both the first side arm connector 68a and the second side arm connector 68b to allow greater adjustment of the patient interface structure 32.

James & Wells Ref: 504864DIV6 3.3.7 Seal Positioning and Stabilizing ure - Seventh Embodiment Referring to Figs. 15a and 15b, according to another sample embodiment , the side strap 38, the top strap 40, and the rear strap 42 of the seal positioning and stabilizing ure 36 are connected by a tor 72. The side strap 38 may be connected to the patient interface structure 32 by a seal oning and stabilizing structure connector 12 which is provided on the patient interface ure 32. The patient interface ure 32 may be connected directly to an air ry tube 16 by a swivel elbow 17. The connector 72 allows the position of each of the straps 38, 40, 42 to be adjusted to allow the patient to effect a seal between the patient interface ure 32 and the airways of the patient and allows the seal positioning and stabilizing structure 36 to be sized and fitted to a variety of patients. 3.3.8 Seal Positioning and Stabilizing Structure – Eighth Embodiment Figs. 24m-24q show a patient interface assembly including an eighth embodiment of a seal positioning and stabilizing structure. The seal positioning and stabilizing structure includes a main strap loop 74, and rear strap 85. With nce to Fig. 24q main strap loop 74 includes a strap connector 82 arranged to t rear strap 85 at an angle A with respect to the crown engaging top portion main loop 74 of about 90° to about 140°, preferably about 95° to about 110°, most preferably about 100°. The closer the angle A is to the preferred values there is a progressive improvement in the fit range of the headgear, allowing the patient interface to comfortably fit a range from smaller to larger heads.

With further reference to Figs. 24q, 16a and 16d, the main strap loop 74 has a curved middle portion in between two lly straight portions. The first straight portion lies over the crown of the patient's head in use. The second straight portion has one end connected with a lateral portion of the patient interface structure, and is generally parallel therewith. The curved middle portion corresponds to the stiffened region 78 discussed below. The angle B between the two straight portions is preferably in the range of about 150° to about 90°, for example about 130° to about 90°, more preferably about 120° to about 100°, most preferably about 111°. The James & Wells Ref: 504864DIV6 closer the angle B is to the red values there is a progressive improvement in the fit range of the headgear, allowing the patient interface to comfortably fit a range from smaller to larger heads. Furthermore, the stiffened, curved portions allows headgear tension forces to be applied to the underside of the patient's nose at a more effective angle, preferably orthogonal to the underside of the nose, without the headgear obscuring the patient's vision, or ting sensitive eye s. In the preferred arrangement there is no sharp change in ion, compared to for example, the ResMed Swift® LT. Furthermore this headgear (i.e. seal positioning and stabilizing structure) arrangement avoids impinging on patient's ears in a wider range of head sizes. ing to Figs. 46a and 46b, an angle Y between a line lly perpendicular to the strap connector 82 and a line extending through the first end of the strap loop 74 may be in a range of from 90° to about 140°, preferably about 95° to about 125°, most preferably about 100°.

Referring to Figs. 16a-16g, as discussed previously with respect to Figs. 44a and 44b, the seal positioning and stabilizing structure may include a main strap loop 74 including right and left main straps 74r, 74l, shown in Fig. 16d and Fig. 16a, respectively. Each main strap 74r, 74l may e a first flexible region 76, a stiffened region 78, and a second flexible region 80. As shown in Figs. 16a-16g, the thicknesses of the regions 76, 78, 80 along the main strap 74r, 74l may be varied to enable the main strap 74r, 74l to be sufficiently stiff in areas under load and flexible in areas where conformance to the face is required. The first flexible region 76 is thinner than the stiffened region 78 and may have a thickness of about 0.5 mm – 1.5 mm, for example about 1 mm. The second flexible region 80 is also r than the stiffened region 78 and may have a thickness of about 1 mm - 3 mm, for example 2 mm. As shown in Figs. 16b, 16c, and 16e, the second flexible region 80 may have a varying thickness and the second flexible region may have increased flexibility at its thinnest portion. The ned region 78 is thicker than the first and second flexible regions 76, 80 and may have a thickness of about 3 mm - 10 mm, for example about 6 mm.

Preferably the main strap loop 74 is molded from a silicone having a Shore A hardness James & Wells Ref: 504864DIV6 in the range of about 40 to about 80, more preferably in the range of about 60 to about 70, most preferably about 65. Making the main strap loop 74 from a harder silicone makes it stiffer, and may allow it to be thinner than were it to be made from a softer silicone. Preferably the main loop 74 is not an air delivery tube, or not attached to an air delivery tube, gh it may be . Using the main loop as an air delivery tube, or coupled to one may reduce the benefits provided by the decoupling arrangements. While the main loop 74 made from the preferred silicone and thickness is more flexible than a foam and fabric structure reinforced with nylon stiffeners, it has sufficient structure that it retains a degree of shape when ng by itself, facilitating use by patients who might otherwise be confused by an overly floppy headgear ure that gives few clues as to how it should be used. Furthermore, making the main loop 74 from silicone in the preferred hardness range, and in the preferred thickness ranges means that improved ity of the seal may be ed, avoidance of sensitive regions of the face, and ed fit range without ing the use of harder or stiffer als (e.g. nylon stabilizers) that may cut into the patient's skin, or leave marks on their face. The curved shape of the stiffened region reduces or eliminates the need for , stiffer stabilizers that may be required were the angle between the crown-engaging top portion and the front portion of the main loop 74 sharper. Furthermore, the use of silicone in the main loop provides a degree of flexure upon movement of the air delivery tube, decoupling it from affecting seal, unlike a more rigid, or inextensible stabilizer. Silicone may provide an improved "grip" to the patient's skin. Molding the main loop is a relatively simple, low waste manufacturing step and does not require additional assembly processes (such as stitching a stiffener to a foam and fabric laminate). Die g a shape that cannot be readily nested from a sheet may result in wasted material. In accordance with a preferred form of the present technology, the rear strap 85 is relatively straight, and hence can be die cut from a sheet of material with relatively little waste. Hence the preferred form of seal positioning and stabilising structure is more cost effective.

The main straps 74r, 74l may have a width of about 5 mm to about 15 mm, for James & Wells Ref: 504864DIV6 example about 10 mm, in the region configured to engage the crown of the patient’s head and may widen to a width of about 15 mm to about 25 mm, for example about 20 mm in the region configured to contact the patient’s face in the region of the cheek, for example in the region around the strap connector 82. The width of the straps 74r, 74l may narrow between strap connector 82 and the tor 84, for example from about 20 mm to about 10 mm, and then increase toward the tor, for example to about 15 mm to about 25 mm, for example about mm.

A strap connector 82 may be provided in the stiffened region 78. The strap connector is ured to receive, for example, a rear strap configured to extend around the back of the head of the patient to secure the seal positioning and stabilizing structure to the patient, and facilitating lengthwise adjustment of the rear strap in one or two points. The back str ap may be formed of the same material as the main straps 74r, 74l, for example, silicone, or formed from foam and fabric, such as BREATHOPRENE®. It should be appreciated that the back strap may be formed of a different material than the main straps 74r, 74l, such as elastic, or from a combination of als. It should also be iated that the durometer of the main straps 74r, 74l may be varied along its length instead of, or in addition, to g the thickness of the main straps 74r, 74l.

Each main strap 74r, 74l includes a patient interface structure connector 84 that is configured to receive a corresponding connector formed on the patient ace structure, described below with respect to Figs. 17a – 17f. As shown in Figs. 16a - 16g, the patient interface structure connector 84 may be in the form of a triangular cut out formed in the end of the main strap 74r, 74l. It should be iated, however, that the patient interface structure connector 84 may comprise a cut out having a different shape than triangular. 3.3.9 Seal Positioning and Stabilizing Structure - Strap Connectors Silicone is more flexible than standard headgear materials, such as BREATHOPRENE®, and may not perform as desired in standard headgear strap connectors.

James & Wells Ref: 504864DIV6 For example, silicone has a tendency to slide in the connector(s) and become loose. As discussed in more detail below, sample embodiments of seal positioning and stabilizing structure strap connectors are particularly suitable for use with silicone seal positioning and stabilizing structure straps, although the sample embodiments are not limited to silicone seal positioning and stabilizing structure straps. 3.3.9.1 Ladder Lock Strap Connector Referring to Figs. 19a and 19b, the straps of the seal oning and stabilizing ure, for example top straps 40, may be d by a ladder lock connector 86. The ladder lock connector 86 may comprise a first side member 88 and a second side member 90. A first cross member 92 and a second cross member 94 extend between the first side member 88 and a second side member 90. A third cross member 96 is spaced from the first cross member 92 to define a first strap slot 100. A fourth cross member 98 is based from the second cross member 94 to define a second strap slot 102. A l aperture 104 is defined between the first cross member 92 and the second cross member 94 to allow threading of ends 40a of the top straps 40 through the central aperture 104 and over respective cross members 92, 94 and under tive cross members 96, 98, as shown in Fig. 19b. As shown in Fig. 19a, third and fourth cross members 96, 98 are wider than first and second cross members 92, 94 to increase the amount of contact between the cross s 96, 98 and the ends 40a of the straps 40. The increased width of the third and fourth cross members 96, 98 thus increases the frictional contact between the ladder lock connector 86 and the straps 40 to provide a more secure fitting of the seal positioning and stabilizing structure.

As shown in Fig. 19a, the first and second side s 88, 90 may include textured surfaces 89, 91, tively, configured to improve a user’s grip on the connector 86 to facilitate connection and/or adjustment of the straps 40 with respect to the connector 86. The textured surfaces 89, 91 may be, for example, ridges. Additionally, the side members 88, 90 may each e a depression at the textured surfaces 89, 91 to receive the user’s fingers.

James & Wells Ref: 504864DIV6 In a t form, shown in Figs. 19c – 19e, ladder lock connector 86 may have leaders 96a and 98a to ensure that end 40a of straps 40 are d tly. The ladder lock connector 86 may only be adjusted when in the configuration shown in Fig. 19b. If silicone seal positioning and stabilizing structure is used, it is unlikely that ladder lock connector 86 will remain aligned as shown in Fig. 19b due to the flexibility of silicone (for example, the ladder lock connector 86 tends to rotate 90). To resolve this, leaders 96a and 98a may be extended distally from cross members 96 and 98. The leaders 96a and 98a may be generally rectangular or any other desirable shape. The leaders 96a and 98a may enclose straps 40 and ends 40a or may enclose only a portion of straps 40 and ends 40a. The leaders 96a and 98a may be about 5 - 30mm long, for example about 10 mm long, as indicated by LL in Fig. 19d. The s 96a and 98a may closely conform to the perimeter formed by straps 40 and ends 40a, i.e. the outline of the strap 40 and the strap end 40a when looped through the connector. Alternatively, as shown in Fig. 19e the leaders 96a and 98a may leave at least a 1mm clearance C, for example about 2 mm, as another example no more than about 10 mm, around the perimeter formed by straps 40 and ends 40a. 3.3.9.2 Discretely Adjustable Strap tors Referring to Figs. 20a and 20b, a strap connector according to another sample embodiment ses a first strap 108 having a first strap connector 110 formed at an end thereof. A second strap 114 has a second strap connector 116 provided at an end thereof. The second strap 114 may comprise a stud 118 that is insertable into a selected aperture 112 formed in the end of the first strap 108. The stud 118 may be generally mushroom shaped in order to lock the first strap 108 in position. The seal positioning and izing structure may thus be adjusted by selecting the appropriate aperture 112 that provides the most comfortable fit for the patient while maintaining an effective seal n the patient ace structure and the patient’s s.

Referring to Figs. 21a and 21b, a seal positioning and stabilizing structure strap connector assembly according to another sample embodiment comprises a first strap 120 having James & Wells Ref: 504864DIV6 a stud 124 formed on an end thereof. A guide 122 is provided at the end of the first strap 120. A second strap 126 of the seal positioning and stabilizing structure may comprise a plurality of apertures or holes 130 that are selectively received by the stud 124 of the first strap 120. The second strap 126 may comprise a ladder lock connector 128 and an end thereof. The second strap 126 is threaded through the guide 122 of the first strap 120 and the stud 124 is inserted into a selected hole or aperture 130 to adjust the g of the seal positioning and stabilizing structure.

Referring to Figs. 22a - 23c, a seal positioning and stabilizing structure strap tor assembly ing to another sample embodiment comprises a first strap 300 having a spring 302 attached on an end thereof. A second strap 301 of the seal oning and stabilizing structure may comprise a ity of ridges or corrugations 303 that are selectively received by the spring 302 of the first strap 300. Spring 302 may comprise a resilient finger 325 that is able to flex when corrugations 303 are pulled past the resilient finger 325 when force F is applied. As shown in Fig. 22a, the resilient finger may be provided on a resiliently cantilevered finger 305 of the spring 302. As also shown in Fig. 22a, the spring 302 may include a cross bar 307 and the first strap 300 may be ted to the spring 302 by looping an end of the first strap 300 around the cross bar 307. Alternatively, the spring 302 may be integrally formed with the first strap 300 as shown in Figs. 23a – 23c. 3.3.9.3 Main Strap Connectors Referring to Figs. 24a-24p, the left main strap 74l of the seal positioning and stabilizing structure comprises a strap connector 82 configured to receive one end of a rear strap of the seal positioning and stabilizing ure. The left main strap 74 l also includes a patient interface structure connector 84l, e.g. a generally triangular cut out, is configured to receive left connector of the patient interface structure. The left main strap 74l also includes a plurality of locking projections 75 and a final locking projection 77. The locking projection 75 may have a generally round, oval, or ical uration. The final locking projection 77 is larger than James & Wells Ref: 504864DIV6 the locking projections 75 and extends above the locking projection 75, as shown for example in Fig. 24b, to prevent the seal positioning and stabilizing structure from being completely disassembled.

Referring to Figs. 24e-24h, the right main strap 74r of the seal oning and stabilizing ure ses a strap connector 82 ured to receive the other end of the rear strap. The right main strap 74r also includes a t interface structure connector 84r, e.g. cut out, that is configured for connection to a right connector of the patient interface structure. A locking connector 79, for example a ladder locking connector, is ed at an end of the right main strap 74r to receive the end of the left main strap 74l. As shown in Fig. 24i, the end of the left main strap 74l is inserted into the ladder locking connector 79 in the ion shown by the arrow to connect the left main strap 74l to the right main strap74r. The end of the left main strap 74l may e a depression 74d to aid in insertion of the end through the locking connector 79.

As shown in Fig. 24l, the locking connector 79 includes a locking projection 81 that is configured to engage the left main strap 74l between g projections 75 to maintain the connection between the left and right main straps 74l, 74r. The locking projection 81 is larger than the space between corresponding locking projections 75 to improve the retention of the main straps 74l, 74r. As shown in Fig. 24l, the final locking projection 77 is higher than the locking projection 75 to prevent the seal positioning and stabilizing structure from being completely disassembled. It should be appreciated that the main straps 74l, 74r and the locking projections 75, 77, 81 may be formed of material that is flexible enough to permit disassembly upon ation of a sufficient force. The main straps 74l, 74r and the g projections 75, 77, 81 may be configured to resist disassembly due to forces such as tube drag or forces normally applied to the seal positioning and stabilizing structure while wearing, and/or sleeping with, the mask system. An advantage of molding the main strap connectors into the straps is that it simplifies the manufacturing process, and is more cost-effective, since an additional fastener is not required.

James & Wells Ref: 504864DIV6 As shown in Fig. 24l, a slot 83 is provided in the right main strap 74r to permit the end of the left main strap 74l to flex downwardly as the locking projection 81 s the locking projections 75. The slot 83 permits the portion of the left main strap 74l that extends over the slot 83 to be displaced downwardly as the locking projection 81 engages the left main strap 74l between locking projections 75.

Referring to Fig. 24m, a rear strap 85 may be connected to the main straps 74l, 74r through the strap connectors 82. Ends 85e of the rear strap 85 may be provided with hook or loop type fasteners to engage corresponding loop or hook fastener material ed on the rest of the rear strap 85 to permit adjustment of the length of the rear strap 85 extending between the main straps 74l, 74r. Although Figs. 24m - 24q show the rear strap 85 as having two adjustable ends 85e, it should be appreciated that the rear strap 85 may be provided with only one adjustable The durometer of the left main strap 74l may be higher in ic areas to provide increased durability, ease of adjustment, and maintenance of shape. For example, the strap connector 82, the portion surrounding the cut out 84l, the g projections 75 and the final locking projection 77 may be provided with a higher durometer than the other portions of the left lateral member 74l. The higher durometer of the locking projection 75 and the final g tion 77 improve the function of the ladder lock buckle formed by the connection of the locking projection 75 with the ladder g connector 79 of the right main strap 74r. The higher durometer provided at the strap connector 82 may improve the durability of the seal positioning and stabilizing structure. The silicone material surrounding the slot of the strap connector 82 may also be of a thickness sufficient to prevent the slot from stretching too much in use. The higher ter of the portion surrounding the cut out 84l may improve connection stability and e durability.

Similarly, the right main strap 74r may have an increased durometer at the ladder locking connector 79, the strap connector 82 and the portion surrounding the cut out 84r to James & Wells Ref: 504864DIV6 provide benefits similar to that discussed above with t to the left main strap 74l.

As shown in Figs. 24a – 24q, the left and right main straps 74l, 74r are connected at top portion of the patient’s head. The rear strap 85 does not include a connection such as a buckle or ladder lock connector. This configuration permits the patient to sleep on either side, or on the patient’s back, without the ladder lock connector 79 causing any discomfort.

Referring to Fig. 24r, the left main strap 74l may e a tapered end 74t that facilitates ion of the left main strap 74l into the connector 79 of the right main strap 74r.

Referring to Figs. 25a-25d, ing to a variant the left main strap 74l may be provided with locking projections 75, but without a final locking projection. As shown in Fig. 25d, the locking projection 81 of the ladder locking connector 79 may be generally about the same size as the locking projections 75 of the left main strap 74l. This permits the connection of the main straps 74l, 74r in a comparatively easier manner than the connection disclosed in Figs.

] The right and left main straps 74r, 74lmay be adjustable by a spring loaded clip that, when squeezed together, opens up and allows the lateral side members to pass through, but when not squeezed holds the straps in a locked on. Such a spring loaded clip is similar to a draw cord that is used to allow for adjustment of a cord, for example a cord that functions as a bag closure or a cord that adjust the fit of a hat or cap.

Referring to Fig. 25e, in an alternative embodiment, the right main strap 74r may be provided with a slit or opening that, when relaxed, is closed, but when squeezed at its furthest edges (as shown by the arrows), opens up and allows the left main strap 74l to pass through the slit or opening. It should be appreciated that the left main strap may include the slit or opening and the right main strap may be inserted n.

The right and left main straps 74l, 74r of the main strap loop 74 may be formed, for e, from silicone. The silicone may be molded to comprise mushroom shaped studs 74m on both lateral side members 74l, 74r. The studs 74m, when pushed together, create an James & Wells Ref: 504864DIV6 interference fit as shown in Fig. 25f. The studs 74m may be any other shape, such as a tree shape, an arrow shape, or a lollipop shape. The studs 74m may also be retrofittable to the lateral side members 74l, 74r or molded with the lateral side members 74l, 74r. 3.3.9.4 Additional Strap Connectors Hook and loop fastener material, e.g. VELCRO®, may be provided to the main straps 74r, 74l, i.e. hook material on one lateral side member and loop al on the other. The hook and loop er material may be attached to the main straps by, for example, adhesive or overmolding the material into the main straps. Alternatively and/or additionally, other ment mechanisms, such as s, elastic or push clips, may be overmolded into the lateral side members. A preferred form of patient interface in accordance with the t technology includes three points of lengthwise adjustment: one on the crown of the patient's head for wise adjustment of the main loop, and one on either side of the patient's head (a subtotal of two) generally above the ears for lengthwise adjustment of the rear strap. Some prior art t interfaces may require adjustment of ten separate points in order to find a suitable seating for the headgear, making the process of fitting more complicated. Preferably the rear strap does not include a buckle at the rear of the patient's head, as such a buckle may be uncomfortable to lie 3.4 t Interface Structure and Seal Positioning and Stabilizing Structure Connectors 3.4.1 Connectors Extend Toward Flexible Base of Patient Interface Structure In use, the patient interface structure 320 may be connected to the main strap loop 74 of the seal positioning and stabilizing structure by ing a connector 322 into the patient interface structure connector (e.g. cut out) 84 of each main strap 74r, 74l. As shown, for example in Fig. 17c, the connector 322 is wider than the patient interface structure extension 323. The connector 322 is also wider than the cut out 84 in the main strap loop 74. The connector 322 is inserted through the cut out 84 to t the patient interface structure 320 to the main strap James & Wells Ref: 504864DIV6 loop 74, as shown in Figs. 18a – 18c. As shown in Figs. 16a and 17a, the cut out 84 and the connector 322 include complementary surfaces 84c, 322c, respectively, that are engaged when the connector 322 is connected to the main strap 74r, 74l. The connector 322 also includes sloped side walls 322s (Fig. 17c) that engage with sloped walls 84s (Fig. 16a) of the cut out 84 when the connector 322 is connected to the main strap 74r, 74l so that the connector 322 and the main strap 74r, 74l t a flush surface upon connection, as shown in Fig. 18b. As shown in Fig. 18a, the cut out 84 may include inwardly directed projections 84p that will engage the end of the connector 322 upon connection of the patient interface structure 320 to the main strap loop 74 (i.e. the right and left main straps 74r, 74l) to provide a more secure ment of the t ace structure 320 to the main strap loop 74 of the seal positioning and stabilizing structure. 3.4.2 Connectors Extend Toward Seal of Patient Interface Structure According to another sample ment, shown in Figs. 18d – 18f, the connector 322 may extend from the extension 323 generally in the direction of the nozzles 328 and away from the flexible base 329, as shown in Fig. 18d. The connector 84 is placed over the connector 322 so that when the connector 322 is engaged with the connector 84, the extension 323 is visible, as shown in Figs. 18e and 18f. The assembly may be secured in the same manner described above with respect to Figs. 18a – 18c and may provide a more secure connection when the mask system is in use.

Referring to Fig. 18g, the left and right connectors 3221, 322r, respectively, of the patient interface structure 320 are connected to the left and right main straps 741, 74r, respectively, of the seal positioning and stabilizing structure through the left and right connectors (e.g. cut outs) 84l, 84r, respectively. The geometry of the connectors 322l, 322r matches the geometry of the cut outs 84l, 84r to provide an intuitive ly for the user. The user may get a tactile tion that the connectors 322l, 322r are properly ed into the cut outs 84l, 84r and led in the connected position.

James & Wells Ref: 504864DIV6 3.4.3 Connectors with Alignment Indicators Referring to Fig. 18h, in order to ensure t alignment of the patient interface structure 320 into the left main strap 74l and the right main strap 74r of the seal positioning and stabilizing structure, the connectors 322l, 322r may include indicia 340 which te the left side and the right side. The tors 322l, 322r may also include a left indicator tab 342 and a right indicator tab 344 to align the patient interface structure 320 correctly in the seal positioning and stabilizing structure. As shown in Fig. 18h, the indicator tabs 342, 344 may have different shapes to facilitate ent of the patient interface structure 320 in the seal oning and stabilizing structure. Although the alignment indicator tabs 342, 344 are shown on the connectors 322l, 322r of the patient interface structure 320, it should be appreciated that the alignment indicator tabs may be provided on the main straps 74l, 74r of the seal positioning and stabilizing structure, or that the alignment indicator tabs may be provided on both the tors of the patient interface structure and the main straps of the seal positioning and izing structure.

Referring to Fig. 18i, the connectors 322l, 322r, may include a ent number of ent indicator tabs 342, 344 to indicate the proper direction. For example, the left connector 322l may include one indicator tab 342 and the right connector 322r may include two indicator tabs 344. It should also be appreciated that the position of the alignment indicator tabs 342, 344 may be provided in different places to indicate the direction. For example, the left indicator tab 342 may be provided on a side of the connector 322l and the right indicator tabs 344 may be provided on top of the right seal positioning and stabilizing structure connector 322r. It should also be appreciated that the indicia 340 may also be provided, for example, on the ent indicator tabs 342, 344.

As shown in Fig. 18j, according to another sample embodiment, the t interface ure 320 may be aligned properly with the seal positioning and stabilizing structure by providing the left seal positioning and stabilizing structure connector 322l with a different shape James & Wells Ref: 504864DIV6 than the right seal positioning and stabilizing ure connector 322r. As shown in Fig. 18k, the left cut out 84l has a shape ponding to the left connector 322l and the right cut out 84r has a different shape corresponding to the ently shaped right connector 322r. The differently shaped connectors and cut outs ensures proper alignment of the patient interface ure 320 with the seal positioning and stabilizing ure in the assembled on shown in Fig 18l.

Referring to Figs. 18m-18p, the seal positioning and stabilizing structure connectors 322l, 322r may face upwards towards the pillows 328 of the patient interface structure 320. This configuration may be provided to avoid accidental disassembly of the patient interface structure 320 from the seal positioning and stabilizing ure. As shown in Figs. 18o and 18p, the connectors 322l, 322r may include d portions 322s that engage with stepped portions 84s of the lateral members 74l, 74r so that the connection between the patient interface structure and the seal positioning and stabilizing structure cannot be accidentally disassembled by pulling the seal positioning and stabilizing structure up from the tabs. The seal positioning and izing structure must be pushed inwards towards the nasal s 328 to disengage the stepped portions 322s and then pulled upwards in order to disassemble the connection of the patient interface ure and the lateral members of the seal positioning and stabilizing structure.

As shown in Fig. 18q, the cut out 84l may include a notch, or cut out 337, to improve bending of the material of the left strap loop 74l to facilitate connection and disconnection of the tor 322l from the cut out 84l. It should be appreciated that the cut out 337 may be alternatively, or additionally, provided to the right strap loop 74r.

As discussed above, the seal positioning and stabilizing structure is not connected to any "hard" parts, for example a rigid polycarbonate shell or frame such as used in prior art mask assemblies, although it should be appreciated that patient interface structure may be connected to a hard part, such as a rigid frame or shell, that is in turn connected to the seal positioning and stabilizing structure.

James & Wells Ref: 504864DIV6 3.5 Decoupling ements 3.5.1 Hinge or Universal Joint Referring again to Figs. 7a – 7d, the air delivery tube 16 may be connected to the patient interface structure 32 by a decoupling arrangement 44. The decoupling arrangement 44 may comprise, for example, a hinge ism. The decoupling arrangement 44 may comprises a connection between the tube 16 and the patient interface structure 32 that provides more than one axis of rotation. Referring to Fig. 7d, the flexible base 6 of the patient interface structure may be divided into the lower portion 6l and the top n 6t by a hinge or sal joint 440 to further isolate the tube drag forces from the forces of the seal positioning and stabilizing structure. 3.5.2 Flexible Elbow Referring to Fig. 5b, a flexible elbow 409 may comprise a le "skeleton" 411 comprising a plurality of rigid hoops, or rings, 405 connected by a flexible lattice 406. An overmold 408 formed of, for e, silicone is provided over the skeleton 402 to form the flexible elbow. The rings 405 provide a minimal support ure that ensures that the elbow 400 does not collapse, but ins the flexibility of the elbow 409 and prevent occluding. 3.5.3 Diaphragm In another form, the decoupling arrangement 44 may comprise a diaphragm between an elbow connected to the tube 16 and the t interface structure 32, or the flexible base 6 of the patient interface structure 32. The diaphragm may be a thinned section with a flat cross section. atively, the cross section of the diaphragm may be wave-shaped, zig-zagged, or any other desired shape.

Referring to Figs. 5c and 5d, the elbow 400 may have a rigid collar 410 that is supported by a diaphragm 414 that is provided between the collar 410 and a rigid frame 412, or a relatively more rigid section, of the patient interface ure. The diaphragm 414 may be flat, or have a wave-shaped configuration, or a concertina-type configuration. The diaphragm 414 James & Wells Ref: DIV6 may be formed of, for example, silicone. 3.5.4 Linking Element ing to Figs. 8l and 8m, seal positioning and stabilizing structure is used to stabilize a mask system on the face of the patient. However, the stabilization can be offset by air delivery tube drag forces. Typically, the frame of a mask system will direct forces from the ar and the air delivery tube in such a way that the mask is still able to seal. In the sample embodiments , seal positioning and stabilizing structure is connected to the patient ace structure, not to the frame. The patient interface ure thus needs to direct the forces, i.e. seal positioning and izing ure and air delivery tube drag forces. As shown in Fig. 8l, a patient interface structure according to an embodiment , for example the ment shown in Fig. 4, the air delivery tube drag force acts on the patient interface structure at the top portion 6t, which may cause the nasal s to be pulled away from the patient’s nares. The patient interface structure shown in Fig. 8l may not be able to direct seal positioning and stabilizing structure and air delivery tube forces while maintaining a seal.

As shown in Fig. 8m, the provision of a linking element(s) to the top portion to isolate the seal positioning and stabilizing structure forces and direct the seal positioning and stabilizing structure and tube drag forces appropriately. The lines of n force are directed through the top portion 6t of the patient interface structure 32, thereby allowing the base portion 6 of the patient interface structure 32 to decouple tube drag forces. The linking element facilitates decoupling of the top portion 6t with respect to the lower portion 6l by drawing the tension lines of force through the top portion of the t interface ure 32 and isolates such forces from the base portion of the patient interface structure. The tension linking element isolates the tube drag force at the base portion 6 of the patient interface structure, for example the lower portion 61, which may include, or be configured as, a gusset. By distributing the forces to the lower portion 6l, the patient interface structure is stabilized in the patient’s nares in use.

James & Wells Ref: 504864DIV6 3.5.5.1 Sealing Ring – First Embodiment Referring to Figs. 9a and 9b, a respiratory mask system according to another sample embodiment includes a t ace structure 32. Fig. 9a illustrates a cross section through the flexible base 6 of the t interface structure 32 in between the nasal pillows 4. It should be appreciated that the patient interface structure may be, for example, a nasal cushion or a full face cushion. It should also be iated that the t interface structure may be formed as a compact oro-nasal interface in a manner similar to that disclosed in U.S. Patent Application Publication 2007/0144525 A1, the entire contents of which are incorporated herein by reference.

For example, the compact oro-nasal interface may be modified to include connectors for the seal oning and stabilizing structure straps provided on the patient interface structure or the nozzles. The t interface structure 32 may be connected to an elbow 60 which may be connected to an air delivery tube. The elbow 60 may include a vent 62 to permit the t of the patient’s exhalation.

The patient interface structure 32 may be swivelably connected to the elbow 60 by a swivel seal ring 64. As shown in Figs. 9a and 9b, the patient interface structure 32 may e a flexible base 6 having an aperture 46 for the introduction of the flow of breathable gas. The aperture 46 may be surrounded by a flange 48 which extends radially inwardly around the aperture 46. The flange may include a chamfer 45 extending around the circumference of the flange 48. As shown in Fig. 9b, the flange 48 of the patient interface ure 32 is received in a space between a first flange 64a and a second flange 64b of the swivel seal ring 64 to form a secure seal assembly. The chamfer 45 allows the flange 48 of the patient interface structure 32 to be inserted and d from the space more easily. The swivel seal ring 64 is maintained on an end of the elbow 60 between a first flange 60a and a second flange 60b of the elbow 60. A radial seal is formed at the contact between the second flange 64b of the swivel seal ring 64 and the second flange 60b of the elbow 60. The connection of the flange 48 of the patient interface structure 32 to the swivel seal ring 64 permits the patient interface structure to swivel or rotate James & Wells Ref: 504864DIV6 with respect to the elbow. The swivel seal ring 64 thus assists ling tube drag forces from the seal. The ment of Figs. 9a and 9b thus replaces the patient interface structure me connection mechanism of the prior art with a t interface structure-to-elbow connection. 3.5.5.2 Sealing Ring – Second Embodiment In a variant shown in Figs. 17h and 17i, the flange 326 of the patient interface structure may have a varied thickness T3. For example, the flange 326 may be formed as a tapered flange 331 so that it is easier to insert into the swivel ring 64. The taper may be an angle α in the range of about 5° - 50°, for example about 15°. The surface of the d flange 331 may be polished to improve sealing. Alternatively, the e of the tapered flange 331 may be textured for easier sliding of the swivel ring 64.

Referring to Fig. 17j, the patient interface structure 320 is connected to a swivel elbow assembly 17 having a hose 16 connected thereto by a sealing ring 64 that is insertable into the aperture 324 of the patient interface structure 320 for engagement with the flange 326. As shown in Fig. 17k, the flange 326 comprises a tapered flange 331 that is ured to be inserted into a groove or slot d by the sealing ring 64.

The tapered flange 331 may be assembled to the sealing ring 64 by simply inserting the sealing ring 64 into the aperture 324 of the t interface structure 320, or by inserting the tapered flange 331 of the patient interface structure 320 over the g ring 64, or by a combination of these actions.

The tapered flange 331 and sealing ring 64 provide a small and simple connection of the patient interface structure 320 to the swivel elbow assembly 17 that does not affect the patient interface structure performance. The sealing ring 64 also allows the swivel elbow assembly 17 to be assembled to the patient interface structure 320 in such a way as not to compromise the retention of the swivel elbow assembly 17 with the patient interface structure 320.

James & Wells Ref: DIV6 3.5.5.3 Sealing Ring – Third Embodiment Referring to Fig. 17l, the aperture 324 of the patient ace structure 320 may include a threaded portion 324t and the sealing ring 64 may comprise a corresponding threaded portion 64t that allows the sealing ring 64 to be threadably fastened to the patient interface structure 320. 3.5.5.4 Sealing Ring – Fourth Embodiment As shown in Fig. 17m, ing to another variant, the aperture 324 of the patient interface structure 320 may have a plurality of holding portions 324h and a corresponding number of releasing portions, or openings, 324r. The sealing ring 64 comprises a corresponding number of projections 64p that are received in the ing portions 324r and rotated into engagement with the holding portions 324h to form a bayonet type connection between the sealing ring 64 and the patient interface structure 320. 3.5.5.5 Sealing Ring – Fifth Embodiment Referring to Figs. 17n and 17o, a swivel seal ring 64 may have an asymmetrical uration including a first flange 64a that has a larger diameter than a second flange 64b. A gap, or space, 64g is provided between the first and second flanges 64a, 64b to receive the flange of the t interface structure. The second flange 64b comprises a sloped surface 64s that facilitates insertion of the sealing ring 64 into the aperture of the patient interface structure. The second flange 64b is configured to contact an edge 60e of the elbow 60 to form a radial seal. 3.5.6 Trampoline Referring to Figs. 26a and 26b, the stalks or neck portions 10 of the nasal pillows 4 may be connected to the top portion 6t of the base portion 6 of the patient interface structure and comprise d, or reduced thickness, portions 7. The d portions 7 allow the pillows 4 to easily spring, or trampoline, and therefore adjust to suit the alar angle of the t more readily.

In a variant shown in Figs. 18p and 18s, the top portion 6t of the flexible base 6 may include thinned ns, or trampolines, 335 n the stalks, or neck portions, 332 of the James & Wells Ref: 504864DIV6 nasal pillows 328 and the linking element 47. 3.5.7 Flexible Base ] Referring to Figs. 42a – 42c, the flexible base 6 of the t ace structure is configured to conform to wrap around the underside of the nose of the patient in use when under tension. The flexible base 6 can assist in decoupling the seal, e.g. the nasal pillows 328, from tube drag forces on the tube 16, which may be connected to the patient interface structure by the elbow 17. As shown in Fig. 42a, ially no tube drag force is exerted on the patient interface ure. The nasal pillows 328 are both in sealing engagement with the patient’s nare.

Referring to Fig. 42b, a force may be exerted on the tube 16 on the right side of the patient’s face.

The flexible base 6 compresses on the right side of the patient’s face while permitting the nasal pillow 328 on the left side of the patient’s face to remain in sealing engagement with the patient’s nare. As shown in Fig. 42b, stalk, or neck n, 332 of the left nasal cushion 328 is less compressed than the stalk 332 of the right nasal cushion 328. It should be appreciated that the compressibility of the stalks 332 and, for example, thinned regions or trampolines around the stalks 332 may further assist in decoupling forces, for example tube drag, exerted on the tube or patient interface structure from the seal. As shown in Fig. 42c, in the case where tube drag is exerted to the left side of the patient’s face, the left side of the flexible base 6 is compressed, as is the stalk of the left nasal pillow 328. The right nasal cushion 328 remains in g engagement with the patient’s right nare. The stalk 332 of the right nasal cushion 328 may articulate to assist in maintaining the right nasal cushion 328 in sealing engagement. ing to Figs. 43a – 43c, the flexible base 6 may also assist in forces, e.g. tube drag, applied in an up and down direction. As shown in Figs. 43a, in a case where no external forces are applied, the nasal cushions 328 are in sealing engagement with the nares of the patient.

As shown in Fig. 43b, if an upward force is applied to the patient interface structure, the flexible base 6 assists in ling the force so the nasal cushions 328 remain in sealing engagement.

As shown in Fig. 43c, if a downward force is applied to the patient interface structure, the James & Wells Ref: 504864DIV6 flexible base 6 assists in decoupling the force so that the nasal cushions 328 remain in sealing engagement with the nares. The stalks 332 may also compress, in the case of the upward force shown in Fig. 43b, or expand, in the case of the downward force shown in Fig. 43c, to assist in decoupling the force(s). It should also be appreciated that thinned regions, or trampolines, provided in the patient interface structure around the stalks and/or at the base of the frustoconical sealing surface or zone may assist in ling the force(s).

Although Figs. 42a – 42c depict decoupling of force(s) in the left to right directions, and Figs. 43a – 43c depict decoupling of force(s) in the up and down directions, the flexible base may assist in decoupling forces in other ions, e.g. directions that are ations of left to right, or up to down, or directions that are toward and away from the face of the patient.

As described above, the plenum of the base of the patient interface ure is semirigid , or flexible, so that the plenum will bend or flex when force, such as tube drag, is d to the patient interface structure. The plenum is semi-rigid, or flexible, enough to maintain the venting of the patient interface structure, for e through a vent provided in an elbow connected to the patient interface structure. In other words, the plenum is igid, or flexible, enough to prevent the plenum from collapsing on itself and ting venting of the patient interface structure. 3.5.8 Flexible Straps As discussed above with respect to Figs. 42a – 43c, the straps, e.g. the le main straps 74r, 74l, may stretch to assist in decoupling force(s) applied to the t interface structure, for example tube drag. The straps may also bend or flex to assist in decoupling force(s) applied to the patient interface structure. For example, the main s) 74r, 74l may bend or flex, in and/or out of a plane defined by the strap(s) to assist in decoupling the force. As another example, the forked region of the strap(s) 74r, 74l defined by the connector 84 may bend, flex, and/or stretch in response to the applied force(s).

Although the various sample embodiments have been described in relation to a seal James & Wells Ref: 504864DIV6 oning and stabilizing structure generally including side straps, a top strap and a rear strap, and a main strap loop and a rear strap loop, it should be appreciated that other seal positioning and stabilizing structures may be used. For example, the seal positioning and stabilizing structure may include straps that are routed around and engage the ears of the patient. The seal positioning and stabilizing structure may comprise elastic and/or inelastic . The seal positioning and stabilizing structure may also be provided in various sizes. The seal positioning and stabilizing structure may be formed from silicone. For example, the seal positioning and stabilizing structure may be molded from silicone as one single piece. However, it should be iated that the seal positioning and stabilizing structure may be molded in l pieces, for e two, three or six pieces. Alternatively, silicones of varying durometer (i.e. hardness) may be co-molded. The silicone may also vary in width and depth (thickness) throughout the seal positioning and stabilizing ure, as shown for example in Figs. 16a – 16g, to strengthen the seal positioning and stabilizing structure in areas where force trations are higher, e.g. the cheek . The straps may also have an anti-sweating feature. For example, the side of the straps configured to contact the patient’s face may be textured to minimize or prevent sweating.

It should also be appreciated that the seal positioning and izing structure and patient interface structure may be formed as one piece with interchangeable nasal pillows, for example as disclosed in Australian Application 2004308536, filed December 24, 2004, the entire contents of which are incorporated herein by reference.

It should also be appreciated that the patient interface systems may comprise a nasal clip, d of a seal positioning and stabilizing structure, to hold the patient interface structure in position on the patient’s face.

] The patient interface structures have been described above in relation to the illustrated sample embodiments as being formed of, for example, silicone. It should be appreciated that the patient interface ures may be formed of, for example, a foam material, such as disclosed in James & Wells Ref: 504864DIV6 International Applications , filed July 30,2007, and , filed July 27, 2007, and Australian Provisional Application 2007906102, filed November 6, 2007, the entire contents of all three applications being incorporated herein by reference. It should also be appreciated that the patient interface structure may comprise a gel.

While various sample embodiments discussed above have been described with respect to nasal pillows or prongs, it should be appreciated that other forms of nozzles or nare seals maybe used, for example as disclosed in U.S. Patent 4,782,832 (Trimble), U.S. Patent 7,201,169 (Wilkie et al.), U.S. Patent 328 (Wood), and While the invention has been described in connection with what are tly considered to be the most practical and red 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 ements included within the spirit and scope .

Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of r embodiment to realize yet other embodiments. Further, each independent e or component of any given assembly may constitute an additional embodiment. Furthermore, each individual component of any given ly, one or more portions of an individual component of any given assembly, and various combinations of components from one or more embodiments may include one or more ntal design es. In addition, while the invention has particular application to patients who suffer from OSA, it is to be appreciated that ts who suffer from other illnesses (e.g., congestive heart failure, diabetes, morbid obesity, stroke, ric surgery, etc.) can derive benefit from the above teachings. Moreover, the above teachings have applicability with patients and non-patients alike in non-medical applications.

JAWS Ref: 504864DIV6

Claims (66)

WHAT IS CLAIMED IS:

1. A patient interface system for delivery of a supply of air at positive pressure to the entrance of a patient’s airways for treatment of sleep disordered breathing, comprising: a patient interface structure which comprises a seal forming structure configured to sealingly engage a surface of the patient’s face, and a seal positioning and stabilising structure configured to in use connect to the patient interface structure, wherein the seal oning and stabilising structure comprises: a pair of side straps configured to extend along a respective side region of the patient’s face in use, a pair of top straps ured to extend across a top region of the patient’s head, the pair of top straps ing a first top strap and a second top strap, a rear strap configured to extend around a rear region of the patient’s head, wherein each side strap has increased rigidity as ed to the rear strap, wherein the pair of top straps comprises a strap connector for connecting the first top strap and the second top strap to one another and selectively adjusting a position of the first top strap relative to the second top strap when connected to thereby adjust an effective length of the top straps, wherein the strap tor comprises: a first part having a locking projection disposed on the first top strap, and a second part having a plurality of holes disposed in the section top strap, and n the locking projection is configured to in use engage with one of the holes to lock the first top strap in position relative to the second top strap.

2. The patient interface system according to claim 1, wherein the seal-forming structure is configured to cover part, or all, of one or more of the patient’s nose and mouth. JAWS Ref: 504864DIV6

3. The patient interface system according to either claim 1 or claim 2, wherein the t interface structure is a nasal patient ace structure.

4. The patient interface system according to either claim 1 or claim 2, wherein the t interface structure is a full face patient ace ure.

5. The patient interface system according to any one of claims 1 to 4, wherein the t interface structure is configured to in use flexibly wrap around at least a portion of an underside of the patient’s nose.

6. The patient interface system according to claims 1 to 5, wherein the patient interface structure is configured to accommodate different alar angles.

7. The patient interface system according to any one of claim 1 to 6, wherein the seal positioning and stabilising structure permits rotation of the patient interface structure about a rotation axis to change the orientation of the patient interface ure relative to the seal positioning and stabilising structure to accommodate different naso-labial angles in use.

8. The patient interface system according to any one of claims 1 to 7, wherein the seal positioning and stabilising structure permits rotation of the patient interface structure about a rotation axis to change the orientation of a the t interface structure relative to the seal positioning and stabilising structure to accommodate different positions of the patient interface structure in use.

9. The patient interface system ing to either claim 7 or claim 8, wherein the rotation axis is parallel to a line drawn through both eyes of the patient and located below the nose of the patient.

10. The patient interface system ing to any one of claims 1 to 9, wherein the patient interface structure further comprises an aperture for introduction of a flow of pressurised breathable gas into the patient interface ure.

11. The patient interface system according to any one of claims 1 to 10, wherein the patient ace structure includes a flexible base portion.

12. The patient interface system according to claim 11 when dependent on claim 10, wherein the flexible base portion includes the re.

13. The patient interface system according to any one of claim 1 to 12, wherein the seal g structure is supported by a / the flexible base portion. JAWS Ref: 504864DIV6

14. The patient interface system ing to any one of claims 1 to 13, wherein the patient ace ure is formed of a flexible material.

15. The patient interface system according to claim 14, wherein the flexible material is one or more of silicone, foam, and gel.

16. The patient interface system according to any one of claims 1 to 15, wherein the patient interface structure is formed in one piece.

17. The t interface system according to any one of claims 1 to 16, wherein the patient interface structure comprises areas with varying ies and/or hardness.

18. The patient interface system according to any one of claims 1 to 17, wherein the patient interface structure is relatively softer in areas configured to engage the patient’s face, and r wherein the patient interface is vely harder or more rigid in areas ted to the seal oning and stabilising structure.

19. The patient ace system according to any one of claims 1 to 18, wherein the patient interface structure is connected to a rigid, or semi-rigid, frame or shell.

20. The patient interface system according to claim 19, wherein the patient interface structure is more flexible than the rigid, or semi-rigid, frame or shell.

21. The patient ace system according to either claim 19 or claim 20, wherein the rigid, or semi-rigid, frame or shell is connected to the seal positioning and stabilising structure.

22. The patient interface system according to any one of claims 19 to 21, wherein the seal positioning and stabilising structure is more flexible than the rigid, or semi-rigid, frame or shell.

23. The patient interface system according to any one of claims 1 to 22, wherein one or more of the side straps, top strap and rear strap are configured to stretch to assist in decoupling s) applied to the patient interface structure.

24. The patient interface system according to any one of claims 1 to 23, wherein one or more of the side straps, top strap and rear strap are configured to bend to assist in decoupling force(s) applied to the patient interface structure.

25. The patient interface system according to any one of claims 1 to 24, wherein at least a portion of the seal positioning and stabilising structure is formed of a foam and fabric laminated material.

26. The patient interface system according to any one of claims 1 to 25, wherein the seal positioning and stabilising structure is configured to direct force s provided JAWS Ref: 504864DIV6 by the straps to maintain the patient interface ure in sealing engagement with the nares of the patient.

27. The patient interface system according to any one of claims 1 to 26, wherein the seal oning and stabilising ure is structured and arranged to produce a force normal to an underside of the t's nose.

28. The patient interface system according to claim 27, wherein the straps extend to a region of the t’s face / head to provide the force normal to the underside of the patient’s nose.

29. The patient interface system according to either claim 27 or 28, wherein the shape of the straps is configured to provide the vector of the force normal to the underside of the patient’s nose.

30. The patient interface system according to any one of claims 27 to 29, wherein the width of the straps is varied to cause the seal forming structure to tilt in the direction of the vector of the force normal to the underside of the patient’s nose.

31. The t interface system according to any one of claims 1 to 30, wherein each side strap has a first width which in use extends across a cheek region of the patient and a second width which in use extends across the patient’s nasal region, and wherein the second width is vely smaller than the first width.

32. The patient interface system according to any one of claims 1 to 31, wherein the thickness of the straps varies to change the rigidity and force bution along the straps.

33. The patient interface system according to any one of claims 1 to 32, wherein a patient contacting side of the straps comprises d edges.

34. The patient interface system according to any one of claims 1 to 33, wherein a/ the patient contacting side of the straps is textured to reduce or prevent sweating.

35. The patient interface system according to any one of claims 1 to 34, wherein each side strap is attached to the patient interface structure in use.

36. The patient interface system according to any one of claims 1 to 35, wherein each side strap is ted to a respective side of the patient interface structure in use.

37. The patient interface system according to any one of claims 1 to 36, wherein each side strap is constructed from a material sufficiently stiff along its longitudinal length to resist bending under the seal positioning and stabilising structure forces, and to conform in an out of plane direction to lie flat on the patient’s face. JAWS Ref: 504864DIV6

38. The patient interface system according to claim 37, wherein each side strap comprises a stiffening element which is ucted from materials including nylon, polypropylene, and/or silicone.

39. The patient interface system according to either claim 37 or claim 38, wherein each stiffening element is threaded through, adhered, or stitched to each respective side strap.

40. The patient ace system according to any one of claims 1 to 39, wherein each side strap traverses the patient’s eye socket without ing the patient’s vision.

41. The patient interface system according to any one of claims 1 to 40, wherein the side straps are configured to permit a/the force vectors of the seal positioning and stabilising structure to pass near the patient’s eyes without obscuring the patient's vision.

42. The patient interface system according to any one of claims 1 to 41, wherein the pair of top straps are configured to each extend at an angle to the rear strap.

43. The patient interface system ing to claim 42, wherein the angle is larger than

44. The patient interface system ing to any one of claims 1 to 43, n the configuration of the pair of top straps and rear strap provides force vectors that increase a sealing force d by the seal positioning and stabilising structure without increasing a tension force applied by the seal positioning and stabilising structure.

45. The patient interface system according to any one of claims 1 to 44, wherein a component of a/the force provided by the pair of top straps is directed upward to increases a/the sealing force applied to the patient interface structure.

46. The patient interface system according to any one of claims 1 to 45, wherein the locking tion is formed on an end portion of the first part of the strap connector.

47. The patient interface system according to any one of claims 1 to 46, n the holes are configured on an end portion of the second part of the strap connector.

48. The patient interface system according to any one of claims 1 to 47, n the locking projection is ed in the form of a stud.

49. The patient interface system according to claim 48, wherein the stud is mushroom shaped. JAWS Ref: 504864DIV6

50. The patient interface system according to any one of claims 1 to47, wherein the g projection is provided in the form of a spring member.

51. The patient interface system according to claim 50, wherein the spring member comprises a resilient finger.

52. The t interface system according to any one of claims 1 to 51, wherein the second part comprises a plurality of ridges or locking tions, wherein the holes are formed by spaces between the ridges or locking projections.

53. The patient ace system according to any one of claims 1 to 52, n the dimensions of at least a portion of the locking projection are larger than the dimensions of the holes to improve engagement of the first part with the second part.

54. The patient interface system ing to any one of claims 1 to 53, wherein the first part and the second part are relatively flexible to permit disengagement upon application of a sufficient force.

55. The patient interface system according to any one of claims 1 to 54, wherein the first part and the second part are formed of a flexible material.

56. The patient interface system according to any one of claims 1 to 55, wherein the first part and the second part are configured to resist disengagement by tube drag forces and/or forces normally applied to the seal positioning and stabilising structure in use.

57. The patient interface system according to any one of claims 1 to 56, wherein the locking tion is relatively le.

58. The patient interface system according to any one of claims 1 to 57, wherein the strap connector comprises a guide for one of the first part and the second part to be inserted through.

59. The patient interface system according to any one of claim 1 to 58, n the strap connector is moulded with the pair of top straps.

60. The patient interface system according to any one of claims 1 to 59, wherein one of the side straps comprises a connector, wherein the rear strap is ted to the side strap using the connector.

61. The patient interface system according to any one of claims 1 to 59, wherein each of the side straps comprises a connector, wherein end regions of the rear strap are connected to the side straps using each respective connector. JAWS Ref: 504864DIV6

62. The patient interface system according to either claim 60 or claim 61, wherein each connector ses a slot for receiving a portion of the rear strap therethrough.

63. The patient interface system according to claim 62, wherein a portion of the rear strap is provided with hook or loop type fasteners to engage corresponding loop or hook ers provided on another portion of the rear strap to permit adjustment of the length of the rear strap.

64. The t interface system according to any one of claims 1 to 63 comprising three points of lengthwise adjustment, wherein one point is on the crown of the patient's head for lengthwise adjustment of the pair of top straps, and another point on either side of the patient's head above the ears for wise adjustment of the rear strap.

65. The patient interface system according to any one of claims 1 to 64, wherein at least one portion of the patient interface structure is formed of a rigid, or semirigid

66. The patient interface system according to claim 65, wherein the rigid, or semirigid material is silicone. WO 52560 (PRIOR ART) WO 52560 moan: WO 52560 / 36W «7; :4 WO 52560 WO 52560 WO 52560 WO 52560 .0."— WO 52560 36(38,40,42<)