Patient interface, seal forming structure and method of manufacturing of the same

Abstract

The present specification is directed to a seal forming structure for a patient interface for delivery of air to a patient's airway, wherein the seal forming structure comprises a first section of a thermoformable material and a second section of another material. The present specification is also directed to a patient interface comprising such a seal forming structure, wherein the patient interface further comprises a shell. The specification is also directed to methods for manufacturing such a patient interface.

Claims

1. A patient interface for treatment of sleep disordered breathing using air pressure by delivery of air to a patient's airway, the patient interface comprising a shell, a carrier portion constructed from a more resilient material than the shell, and a seal forming structure, wherein the carrier portion is T-shaped and comprises a platform region with a generally flat surface, wherein the seal forming structure comprises a first section of a thermoformable material and a second section of another material, the second section comprises a face contacting surface, wherein the first section has a first dimension and a second dimension that is greater than the first dimension, the second dimension being substantially parallel to the face contacting surface and substantially perpendicular to the first dimension, wherein the first section is completely enclosed within the second section, the second section configured to be in contact with an entire perimeter of the first section and configured to contact the patient's face, in use, and wherein the seal forming structure is attached to the platform region.

2. A patient interface according to claim 1, wherein the second section comprises a planar border section for connection to flail the platform region, the planar border section being substantially parallel to the second dimension.

3. A patient interface according to claim 2, wherein the planar border section is a first planar border section, wherein the second section includes a second planar border section opposite the first planar border section, and wherein the second planar border section is configured to directly contact the patient's face, in use.

4. A patient interface according to claim 1, wherein the second section comprises a sealing flange for sealing against a patient's face and a support flange.

5. A patient interface according to claim 1, wherein the thermoformable material is polycaprolactone (PCL) and wherein the material of the second section is an elastic material.

6. A patient interface according to claim 1, wherein the face contacting surface and the second dimension are substantially parallel to the platform region.

7. A patient interface according to claim 1, wherein the first section is substantially malleable above a softening temperature and is substantially rigid below the softening temperature.

8. A patient interface according to claim 7, wherein the softening temperature is between 40° C. and 100° C.

9. A patient interface according to claim 1, wherein the thermoformable material is movably adapted to complement physical characteristics of a patient's face when heat is applied, and is adapted to retain its complementary shape when heat is removed.

10. A patient interface according to claim 1, wherein an outermost perimeter of the first section defines a substantially oval shape in cross-section, and an outermost perimeter of the second section defines substantially the same shape.

11. A patient interface according to claim 10, wherein the first dimension extends along a minor axis and the second dimension extends along a major axis.

12. A patient interface for treatment of sleep disordered breathing using air pressure by delivery of air to a patient's airway, the patient interface comprising a shell and a seal forming structure, wherein the seal forming structure comprises a first section of a thermoformable material and a second section of another material, and wherein the first section is, in a cross sectional view, an elongated section, wherein a longitudinal end of the first section is connected to the shell and areas of the first section not being in contact with the shell are enclosed by the second section, wherein the longitudinal end of the first section is a first mating device made in one piece of the thermoformable material, the first mating device includes a first surface that directly contacts a second surface of a second mating device of the shell in order to form a chemical bond, a moulded mechanical interlock, or a mechanical interlock in the form of a snap-fit connection.

13. Method of manufacturing the patient interface of claim 12, the method comprising: providing the shell and the first section of thermoformable material; connecting the first mating device of the first section of thermo-formable material onto the second mating device of the shell in order to form the chemical bond, the moulded mechanical interlock, or the mechanical interlock in the form of the snap-fit connection; and subsequently, overmoulding the first section of thermoformable material with a second section of another material and thereby forming the seal forming structure.

14. A patient interface according to claim 12, wherein the first mating device is the interface for the chemical bond, wherein the interface for the chemical bond is one of a projection and an aperture.

15. A patient interface according to claim 12, wherein the first mating device is the moulded mechanical interlock, wherein the moulded mechanical interlock connects the first mating device to the second mating device, the second mating device may be received in holes of the first mating device.

16. A patient interface according to claim 12, wherein the first mating device includes one of a projection and an aperture, and the second mating device includes the other of the projection and the aperture, wherein the projection is receivable within the aperture in order to removably secure the seal forming structure to the shell without an additional fastener.

17. A patient interface according to claim 16, wherein the projection includes an overhang that engages the aperture to form the snap-fit connection.

18. A patient interface according to claim 16, wherein the first mating device includes the projection, which extends beyond the second section so as to not be enclosed by the second section.

19. A patient interface according to claim 12, wherein the second section includes a first end and a second end partially enclosing the first section, the first end includes a sealing flange for sealing against a patient's face and a support flange spaced apart from the sealing flange.

20. A patient interface according to claim 12, wherein the first section is completely enclosed when the first mating device is coupled to the second mating device.

21. A patient interface according to claim 12, wherein the first mating device directly contacts the second mating device, and does not contact the second section.

22. A patient interface according to claim 12, wherein the second mating device of the shell is formed as a projection.

23. A patient interface according to claim 12, wherein the second section completely encloses all of the first section besides the first mating device, wherein the second section is formed from a single material, and wherein the second section includes a sealing flange.

24. A patient interface for treatment of sleep disordered breathing using air pressure by delivery of air to a patient's airway, the patient interface comprising a shell and a seal forming structure, wherein the seal forming structure comprises a first section of a thermoformable material and a second section of another material, wherein the first section comprises a perimeter section and a plurality of radially extending web portions connecting the perimeter section to the shell.

25. A patient interface according to claim 24, wherein each web portion of the plurality of web portions includes a first end coupled to the perimeter section, and a second end opposite the first end and extending toward a center of the seal forming structure, the second end being coupled to the shell.

26. A patient interface according to claim 24, wherein a maximum outer dimension of the shell is less than a maximum outer dimension of the perimeter section.

27. A patient interface according to claim 24, wherein the shell is spaced apart inwardly from the perimeter section.

28. A patient interface according to claim 24, wherein the plurality of web portions contact an outermost perimeter of the shell.

29. A patient interface according to claim 24, wherein the first section is completely enclosed by a combination of the second section and the shell.

30. A patient interface according to claim 24, wherein the second section is connected to the shell between adjacent web portions of the plurality of web portions.

31. A patient interface according to claim 24, wherein the second section is connected to both the first section and the shell.

32. A seal forming structure for a patient interface for treatment of sleep disordered breathing using air pressure by delivery of air to a patient's airway, wherein the seal forming structure comprises a section of a material including a first end, a second end, and an insertion axis extending along and between the first end and the second end, said first end including a sealing flange intersecting the insertion axis and configured to contact the patient's face, said second end including a groove configured to receive a section of thermo-formable material along the insertion axis during assembly of the thermoformable material into the groove, wherein the second end is configured to couple to a shell, wherein the groove is configured to remain exposed whether the shell is coupled or uncoupled to the seal forming structure.

33. A seal forming structure according to claim 32, wherein during use of the patient interface the seal forming structure, the shell and a patient's face define an interior space, the groove located outside of the interior space and exposed to ambient during use.

34. Method of manufacturing a patient interface for treatment of sleep disordered breathing using air pressure by delivery of air to a patient's airway, the method comprising: providing the shell and the seal forming structure referred to in claim 32; moulding the shell and the seal forming structure to one another with a moulding material; and locating the section of thermoformable material in the groove.

35. A patient interface according to claim 32, wherein the groove comprises at least one undercut to retain the section of thermoformable material.

36. A patient interface according to claim 32, wherein the thermoformable material is configured to be spaced apart from the shell.

37. A seal forming structure according to claim 32, wherein the groove is symmetrical about the insertion axis.

38. A seal forming structure according to claim 32, wherein the groove forms a substantially T-shaped cross-section.

39. A seal forming structure according to claim 32, wherein the insertion axis intersects with the sealing flange.

40. A seal forming structure according to claim 32, wherein the groove is configured to have the thermoformable material molded therein.

41. A seal forming structure according to claim 32, wherein the second end is configured to be molded to the shell.

42. A seal forming structure according to claim 32, wherein the groove is configured to form a chemical bond with the thermoformable material.

43. A seal forming structure according to claim 32, wherein the groove is at least partially formed between a base, a first wall, and a second wall opposite the first wall, wherein the first wall includes a first undercut and the second wall includes a second undercut, wherein the first wall includes a first end coupled to the base and a second free end, and wherein the second wall includes a third end coupled to the base and a fourth end configured to be molded to the shell.

44. A seal forming structure according to claim 32, wherein the insertion axis is parallel between the first end and the second end.

45. A seal forming structure according to claim 32, wherein the groove is configured to receive the section of thermoformable material along the insertion axis in a direction toward the sealing flange.

Description

3 BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present technology is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference numerals refer to similar elements including:

3.1 Treatment Systems

(2) FIG. 1a shows a system including a patient 1000 wearing a patient interface 3000, in the form of a nasal pillows, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000. A bed partner 1100 is also shown.

(3) FIG. 1b shows a system including a patient 1000 wearing a patient interface 3000, in the form of a nasal mask, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000.

(4) FIG. 1c shows a system including a patient 1000 wearing a patient interface 3000, in the form of a full-face mask, receiving a supply of air at positive pressure from an RPT device 4000. Air from the RPT device is humidified in a humidifier 5000, and passes along an air circuit 4170 to the patient 1000.

3.2 Respiratory System and Facial Anatomy

(5) FIG. 2a shows an overview of a human respiratory system including the nasal and oral cavities, the larynx, vocal folds, oesophagus, trachea, bronchus, lung, alveolar sacs, heart and diaphragm.

(6) FIG. 2b shows a view of a human upper airway including the nasal cavity, nasal bone, lateral nasal cartilage, greater alar cartilage, nostril, lip superior, lip inferior, larynx, hard palate, soft palate, oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

(7) FIG. 2c is a front view of a face with several features of surface anatomy identified including the lip superior, upper vermilion, lower vermilion, lip inferior, mouth width, endocanthion, a nasal ala, nasolabial sulcus and cheilion. Also indicated are the directions superior, inferior, radially inward and radially outward.

(8) FIG. 2d is a side view of a head with several features of surface anatomy identified including glabella, sellion, pronasale, subnasale, lip superior, lip inferior, supramenton, nasal ridge, alar crest point, otobasion superior and otobasion inferior. Also indicated are the directions superior & inferior, and anterior & posterior.

(9) FIG. 2e is a further side view of a head. The approximate locations of the Frankfort horizontal and nasolabial angle are indicated. The coronal plane is also indicated.

(10) FIG. 2f shows a base view of a nose with several features identified including naso-labial sulcus, lip inferior, upper Vermilion, naris, subnasale, columella, pronasale, the major axis of a naris and the sagittal plane.

(11) FIG. 2g shows a side view of the superficial features of a nose.

(12) FIG. 2h shows subcutaneal structures of the nose, including lateral cartilage, septum cartilage, greater alar cartilage, lesser alar cartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue, frontal process of the maxilla and fibrofatty tissue.

(13) FIG. 2i shows a medial dissection of a nose, approximately several millimeters from a sagittal plane, amongst other things showing the septum cartilage and medial crus of greater alar cartilage.

(14) FIG. 2j shows a front view of the bones of a skull including the frontal, nasal and zygomatic bones. Nasal concha are indicated, as are the maxilla, and mandible.

(15) FIG. 2k shows a lateral view of a skull with the outline of the surface of a head, as well as several muscles. The following bones are shown: frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal, temporal and occipital. The mental protuberance is indicated. The following muscles are shown: digastricus, masseter, sternocleidomastoid and trapezius.

(16) FIG. 2l shows an anterolateral view of a nose.

3.3 Patient Interface, Seal Forming Structure and Method of Manufacture

(17) FIG. 3a shows a patient interface in the form of a nasal mask in accordance with one form of the present technology.

(18) FIG. 4a shows a cross sectional view of patient interface in accordance with one form of the present technology.

(19) FIG. 4b shows an enlarged detail of the patient interface of FIG. 4a.

(20) FIGS. 5a-5c show various aspects of patient interfaces in accordance with forms of the present technology.

(21) FIGS. 6a-6g show still different aspects of patient interfaces in accordance with forms of the present technology.

(22) FIGS. 7a-7c show still further aspects of patient interfaces in accordance with forms of the present technology.

(23) FIGS. 8a and 8b show still further aspects of patient interfaces in accordance with forms of the present technology.

(24) FIG. 9a shows a molding tool for manufacture of a patient interface in accordance with the present technology.

(25) FIG. 9b shows a patient interface manufactured with the tool depicted in FIG. 9a.

4 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

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

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

4.1 Therapy

(28) In one form, the present technology comprises a method for treating a respiratory disorder comprising the step of applying positive pressure to the entrance of the airways of a patient 1000.

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

(30) In certain examples of the present technology, mouth breathing is limited, restricted or prevented.

4.2 Treatment Systems

(31) In one form, the present technology comprises an apparatus or device for treating a respiratory disorder. The apparatus or device may comprise an RPT device 4000 for supplying pressurised air to the patient 1000 via an air circuit 4170 to a patient interface 3000.

4.3 Patient Interface

(32) A non-invasive patient interface 3000 in accordance with one aspect of the present technology comprises the following functional aspects: a seal-forming structure 3100, a plenum chamber 3200, a positioning and stabilising structure 3300 and one form of connection port 3600 for connection to air circuit 4170. In some forms a functional aspect may be provided by one or more physical components. In some forms, one physical component may provide one or more functional aspects. In use the seal-forming structure 3100 is arranged to surround an entrance to the airways of the patient so as to facilitate the supply of air at positive pressure to the airways.

(33) 4.3.1 Seal-Forming Structure

(34) In one form of the present technology, a seal-forming structure 3100 provides a seal-forming surface, and may additionally provide a cushioning function.

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

(36) In one form, the seal-forming structure 3100 comprises a sealing flange 3110 and a support flange 3120. The sealing flange 3110 comprises a relatively thin member with a thickness of less than about 1 mm, for example about 0.25 mm to about 0.45 mm, that extends around the perimeter 3210 of the plenum chamber 3200. Support flange 3120 may be relatively thicker than the sealing flange 3110. The support flange 3120 is disposed between the sealing flange 3110 and the marginal edge of the plenum chamber 3200, and extends at least part of the way around the perimeter 3210. The support flange 3120 is or includes a spring-like element and functions to support the sealing flange 3110 from buckling in use. In use the sealing flange 3110 can readily respond to system pressure in the plenum chamber 3200 acting on its underside to urge it into tight sealing engagement with the face.

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

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

(39) In one form, the non-invasive patient interface 3000 comprises a seal-forming portion that forms a seal in use on an upper lip region (that is, the lip superior) of the patient's face.

(40) In one form the non-invasive patient interface 3000 comprises a seal-forming portion that forms a seal in use on a chin-region of the patient's face.

(41) 4.3.2 Plenum Chamber

(42) The plenum chamber 3200 has a perimeter 3210 that is shaped to be complementary to the surface contour of the face of an average person in the region where a seal will form in use. In use, a marginal edge of the plenum chamber 3200 is positioned in close proximity to an adjacent surface of the face. Actual contact with the face is provided by the seal-forming structure 3100. The seal-forming structure 3100 may extend in use about the entire perimeter of the plenum chamber 3200.

(43) 4.3.3 Positioning and Stabilising Structure 3300

(44) The seal-forming portion 3100 of the patient interface 3000 of the present technology may be held in sealing position in use by the positioning and stabilising structure 3300.

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

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

(47) In certain forms of the present technology, a positioning and stabilising structure 3300 comprises a strap that is extensible, e.g. resiliently extensible. For example the strap may be configured in use to be in tension, and to direct a force to draw a cushion into sealing contact with a portion of a patient's face. In an example the strap may be configured as a tie.

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

(49) 4.3.4 Vent

(50) In one form, the patient interface 3000 includes a vent 3400 constructed and arranged to allow for the washout of exhaled carbon dioxide.

(51) One form of vent 3400 in accordance with the present technology comprises a plurality of holes, for example, about 20 to about 80 holes, or about 40 to about 60 holes, or about 45 to about 55 holes.

(52) The vent 3400 may be located in the plenum chamber 3200. Alternatively, the vent 3400 is located in a decoupling structure 3500, e.g., a swivel.

(53) 4.3.5 Decoupling Structure(s)

(54) In one form the patient interface 3000 includes at least one decoupling structure 3500, for example, a swivel or a ball and socket.

(55) 4.3.6 Connection Port

(56) Connection port 3600 allows for connection to the air circuit 4170.

(57) 4.3.7 Forehead Support

(58) In one form, the patient interface 3000 includes a forehead support 3700.

(59) 4.3.8 Anti-Asphyxia Valve

(60) In one form, the patient interface 3000 includes an anti-asphyxia valve.

(61) 4.3.9 Ports

(62) In one form of the present technology, a patient interface 3000 includes one or more ports that allow access to the volume within the plenum chamber 3200. In one form this allows a clinician to supply supplemental oxygen. In one form, this allows for the direct measurement of a property of gases within the plenum chamber 3200, such as the pressure.

4.4 Further Description of Examples of the Patient Interface, the Seal Forming Structure and Manufacturing Methods

(63) FIG. 5a shows one aspect in accordance with the present technology. In this aspect of the present technology, a seal forming structure 3100 of a patient interface 3000 is provided. This seal forming structure 3100 may be a user formable pad preferably consisting of or comprising a thermo-formable material. In accordance with the center section/middle Figure of FIG. 5a, e.g., heat (depicted as wavy lines) may be applied to seal forming structure 3100, such that this seal forming structure 3100 softens. In this regard, it is pointed out that the present specification is in particular and preferably directed to a thermo-formable structure. However, even though the embodiments are directed thereto, the skilled person will understand that the present technology may also be employed be means of other user formable structures. The seal forming structure 3100 may then, in this softened state, be applied to a patient's face (see right depiction in FIG. 5a) and assume the approximate shape of the patient's face. When the seal forming structure 3100 cools down again, it will remain in this shape. Thereby, an individual or customized shape and thus fit of the seal forming structure on this particular user's face is achieved.

(64) To achieve this, the seal forming structure 3100 may have a thermo-formable section 3150 (see, e.g., FIGS. 4a and 4b). This section may be made of a material having a specific transition temperature. Below this transition temperature, which may also be referred to as a melting temperature or as a softening point, the material maintains its shape. Above this transition temperature, the material may be deformed. Typically, this transition temperature is above the temperature a patient interface 3000 typically assumes in use. That is, this transition temperature may be, e.g., in the range of 40° C.-100° C. Lower temperatures of this range, such as 40° C. to 60° C. may be preferred to avoid to allow contact with a user's skin for customization without causing pain or skin damage to the face due to the material's temperature. As discussed, a user may heat the seal forming structure 3100 (either on its own or with the remainder of the patient interface 3000) above the transition temperature, e.g., by means of warm water, infrared radiation, microwave radiation or other means of heating available in the user's household and then deform the seal forming structure 3100, preferably by applying it to or pressing it on his or her face. When the seal forming structure 3100 then cools down again below the transition temperature, it will maintain the respective shape. As a result the seal forming structure may better fit to the patient's physiognomy of the face. Thus, a better sealing may be achieved and a more comfortable fit of the patient interface 3000 to the user.

(65) This may be achieved in various embodiments of the present technology. Turning generally to FIG. 4a, a patient interface 3000 typically comprises a shell 3250. If the patient interface 3000 is realized as a mask, this shell 3250 may also be referred to as a chassis or as a mask chassis. The shell 3250 may be formed from a relatively rigid material, such as polycarbonate. However, other materials, such as polyamide, polybutylene terephthalate and/or others may also be used for this embodiment and the other embodiments of the present technology. Typically, the patient interface 3000 also comprises a connection port 3600 for connection to a breathing gas line. The connection port 3600 may either be adapted for direct connection of a breathing gas line or for indirect connection to such a breathing gas line, e.g., by means of a swivel elbow. The patient interface 3000 may also comprise a vent 3400 including a plurality of apertures for washing out a exhaled air. Furthermore, the embodiment depicted in FIGS. 4a and 4b also comprises a seal forming structure 3100, such as a pad. This seal forming structure 3100 includes the thermo-formable section 3150. The thermo-formable section 3150 may have a substantial oval shape in cross-section (see e.g., FIG. 4b). Thus, the thermo-formable section 3150 may have a substantially round shape, and have a first dimension (e.g., a horizontal dimension as shown in FIG. 4b) measured generally perpendicularly to a larger, second dimension (e.g., a vertical dimension as shown in FIG. 4b). The seal forming structure 3100 also comprises a second portion 3160 of another material. In the embodiment depicted in FIGS. 4a and 4b, this section of another material completely surrounds or encloses the thermo-formable section 3150, which may therefore also be referred to, in this embodiment, as a thermo-formable core section. Thus, the second portion 3160 may adapt a shape that is substantially the same as the thermo-formable section 3150. In other words, the second portion 3160 may also have a substantially oval shape. However, the second portion 3160 may have a pair of sides that are substantially straight (e.g., as opposed to curved), and may be substantially parallel to the second dimension. As depicted, the second section 3160 is adapted to come into contact with a patient's face (e.g., via one of the substantially straight sides) during use of the patient interface 3100. Typically, the second section 3160 is therefore preferably formed of a skin-friendly and/or seal enhancing material, such as, for example, silicon. In the depicted embodiment, the patient interface also comprises a carrier portion 3252 or cushion structure. One end of the carrier portion 3252 may be T-shaped. The carrier portion 3252 may be formed integrally with shell 3250. However, alternatively, carrier portion 3252 may also be formed from another material than shell 3250. For example, carrier portion 3252 may also be formed of a material being more resilient then shell 3252 to allow, e.g., for bending of the carrier portion 3252. As depicted in FIG. 4b, carrier portion 3252 may have a T-shaped end section—also see FIGS. 5b and 5c being sections along line A-A of FIG. 5a. Such an end section may include a platform region 3254 (preferably the T-beam of the T-shape cross sectional structure), which may be generally flat. The seal forming structure 3100 may be applied to this platform region 3254, e.g., by means of an adhesive such as an adhesive strip 3190, so that the other substantially straight side contacts the platform region 3254. In this regard, seal forming structure 3100 may also have a substantially flat end section to allow for easy connection to platform region 3254 by means of adhesive 3190.

(66) FIGS. 5b and 5c depict the cross-section of different embodiments. The main difference of the two embodiments depicted in FIGS. 5b and 5c resides in the fact that the seal forming structure 3100 of the embodiment in FIG. 5c includes a sealing flange 3110. This sealing flange 3110 may also be referred to as a sealing membrane or as a sealing lip. This sealing flange 3110 is a structure comprising, in a cross sectional view as depicted in FIG. 5c, an elongation which is substantially larger than its thickness. In this regard, the sealing flange 3110 may also be referred to as being a thin section. The sealing flange 3110 may allow for a particularly safe and comfortable seal between the patient interface and the user's face. As depicted, the sealing flange 3110 is formed integrally with the second section 3160. That is, in other words, the sealing flange 3110 is formed as a part of this second section 3160.

(67) As discussed, in the embodiments depicted in FIGS. 4 and 5, the thermo-formable section 3150 may be completely enclosed by, surrounded by or embedded within the second section 3160. In other words only the second material of section 3160 of seal forming structure 3100 may be exposed to the outside. In again other words, a patient using this patient interface may only come into contact with second section 3160, but not with the thermo-formable section 3150. This may be beneficial, as the patient, when handling seal forming structure 3100, would only come into contact with the section 3160, which may be generally formed of skin-friendly material. This may broaden the choice of thermo-formable materials to be used for thermo-formable section 3150. Furthermore, it may also give the patient a more comfortable feel of the seal forming structure 3100, as the patient only comes into contact with materials, which are already known to him. In particular, this may also improve patient compliance.

(68) Still further aspects of the embodiment depicted in FIG. 5a to FIG. 5c may include that the seal forming structure 3100, e.g., a user formable pad, may be applied to a carrier portion 3252, that is a carrier system, preferably by means of adhesive. The shaping of the seal forming structure 3100 will transfer to the carrier system by deforming the respective component. Prior to forming, the seal forming structure 3100 may be substantially flat and shaped suitable to correspond to the carrier portion 3252. This may also include the additional advantages of the respective seal forming structure 3100 being replaceable and enabling an upgrade of existing patient interfaces.

(69) The present technology, however, is not limited to the embodiment depicted in FIGS. 4 and 5. Another preferred embodiment of the present technology is also depicted in FIGS. 6a to 6g. FIG. 6a again depicts the general outline of a patient interface 3000 including a shell or chassis 3250 and a seal forming structure 3100. Again, a connection portion 3600 for connection of a tube or an elbow is included. FIG. 6b depicts a cross-sectional view along line A-A of FIG. 6a. It should be noted that FIGS. 6a and 6b (as well as FIGS. 6c to 6e) depict a patient interface 3000 (or parts/details thereof) during the manufacturing process, that is before the patient interface is ready for use by a patient. In particular, the seal forming structure 3100 is not yet completely formed in these FIGS. 6a to 6e. To the contrary, in these Figures, the patient interface 3000 to be formed includes the shell 3250 and the thermo-formable section 3250 of seal forming structure 3100. The shell 3250 and the thermo-formable section 3150 may be connected to each other in a variety of ways, as depicted in FIGS. 6c to 6e. According to FIG. 6c, there may be provided an interface 3256 shaped to support a chemical bond between the thermo-formable section 3150 and the shell 3250, such interface may be a projection. In the embodiments discussed in conjunction to FIGS. 6a to 6g, the respective section of the shell 3250 may also be referred to as a substrate, onto which the thermo-formable section 3150 is applied. According to FIG. 6d, there may also be provided a molded mechanical interlock 3258 for connection of the shell or substrate 3250 and the thermo-formable section 3150. This may be achieved by provision of a grid like structure comprising holes between structural sections 3258. Furthermore, the tool sections may also be connected to each other by means of a mechanical interlock 3260, such as a snap fit, as depicted in FIG. 6e. However, as will be apparent, the skilled person may also use other means to interconnect the substrate 3250 and the thermo-formable section 3150.

(70) As depicted (see, e.g., FIG. 6b) the thermo-formable section 3150 may have a generally elongated shape. That is, in a cross sectional view, one dimension of the thermo-formable section may be substantially larger than another dimension. In this regard, the thermo-formable section 3150 may be thin. In other words, the thermo-formable section 3150 may also be referred to as a fin 3150.

(71) In other words, and as described above and below, the FIG. 6a shows a frontal view of a mask chassis with a thermoformable fin around the entire circumference, FIG. 6b a cross section of same. FIGS. 6c to 6e illustrate different details of means of connection between chassis and thermoformable fin. FIG. 6f shows a chassis and thermo-formable fin (which may use any of the principles, e.g. as shown in and discussed with regard to FIGS. 6c to 6e) overmoulded in silicone to form a mask cushion. FIG. 6g shows a detail of a cross sections of the thermoformable fin deformed after the adaption process.

(72) As discussed, FIGS. 6a-6e depict the patient interface 3000 in an intermediate state of the production process. In addition to the structures discussed above in conjunction to FIGS. 6a-6e, a second material is applied to the patient interface 3000 to form the second section 3160 of seal forming structure 3100, here not simply a pad but a cushion-structure. In this context, it should be noted that the general discussion of a pad includes reference to a cushion and vice-versa. Again, typically a material suitable for skin contact, that is skin-friendly material may be used for the material of the second section 3160. As an example, silicon may be used.

(73) Generally, this second section 3160 of seal forming structure 3100 may be applied to the other parts by means of over molding. That is, the two component part depicted in FIGS. 6a-6e may be inserted into a tool for over molding and may be over molded, e.g., with silicon, to form the seal forming structure 3100, such as the pad or cushion. Thus, a three component (3K) patient interface would be formed with a thermo-formable element.

(74) After formation of the patient interface 3000 in such a way, the user may heat up the patient interface 3000 to soften the thermo-formable section or thermo-formable element 3150 and apply it to the face so that this element may take shape. The thermo-formable section, that is, in this embodiment, the thermo-formable fin, may also be (pre-)shaped to match a patient's generalized physiognomy quite closely, thereby limiting the amount of shaping required to achieve the adaptation to individual features. As indicated above, FIG. 6f shows a preferred structure before heating and customization while FIG. 6g shows the same preferred structure after thermoforming.

(75) FIGS. 6f and 6g show two cross sectional views along, e.g., lines A-A and B-B (which are basically identical cross sections but simply refer to different points in time, i.e. one before A-A and one after thermoforming B-B) of FIG. 6a, however, only after over-molding with a second material. While FIG. 6a shows the structure before thermoforming, FIG. 6b shows the structure after shaping by a patient has taken place. As will be apparent, the part of the thermo-formable section 3150 in FIG. 6g has been deformed vis-à-vis the former state of the thermo-formable section 3150 as seen in FIG. 6f. While the part of the thermo-formable section 3150 in FIG. 6f has a thin, fin-like shape, the part of the thermo-formable section 3150 in FIG. 6g has been compressed to adopt a more bulky cross-sectional shape. That is, in other words, the amount of forming required may not be uniform around the perimeter of the patient interface. Instead, there may be areas with more deformation and/or deflection and other areas with less deformation and/or deflection.

(76) Furthermore, FIGS. 6f and 6g also depict the seal forming structure 3100 to comprise both a sealing flange 3110 and a support flange 3120. These may be formed integrally with the second section 3160. In other words, these sections may also be referred to be part of the second section 3100, that is, in other words, the second section 3160 comprises the sealing flange 3110 and the support flange 3120. However, the skilled person will readily understand that the provision of sealing flange, e.g. membrane 3110 and undercushion 3120, in this embodiment is only exemplary—that is, the skilled person may also not include these features in the present embodiment or may, alternatively, include the features of a sealing flange 3110 and a support flange 3120 in the other embodiments, such as the embodiment depicted in FIGS. 4a to 5b.

(77) As is also depicted in FIGS. 6f and 6g, the thermo-formable material 3150 may be completely surrounded by other material. That is, all the surface sections of the thermo-formable section 3150 not being in contact with substrate 3250 are in contact with second section 3160 of seal forming structure 3100. In other words, no portion of the thermo-formable section 3150 is exposed to ambient, such that the user will not come into contact with thermo-formable section 3150, such that the user only comes to contact with material he is used to, which may improve, e.g., user compliance. In other words, as depicted and discussed, part of the thermo-formable material may not be covered or surrounded by second material or section 3160 of seal forming structure 3100 but in contact with and covered by substrate 3250.

(78) FIGS. 7a to 7c depict yet another embodiment of the present technology. Again, FIGS. 7a and 7b depict the patient interface 3100 before the final step of over molding and FIG. 7c depicts the patient interface 3000 after over-molding has taken place. According to FIG. 7a, the patient interface 3000 to be formed includes a shell or chassis 3250 with a connection port 3600 (also see the sectional view of FIG. 7b). Furthermore, the patient interface 3000 again comprises a thermo-formable section 3150. The thermo-formable section 3150 includes a perimeter section 3152 and a plurality of leg members or web portions 3154 connecting the perimeter section 3152 to the mask shell 3250. In the depicted embodiment, there are provided three web portions 3154, however, the skilled person will understand that also a different number of web portions 3154, such as 2, 4, 5 or more web portions may be provided. The web portions 3154 are preferably also made of the thermo-formable material, but may also be made of another material.

(79) FIG. 7c again depicts a cross sectional view along line A-A of FIG. 7a after over molding has taken place. As will be apparent, this embodiment, too, comprises a seal forming structure 3100 including a thermo-formable section 3150 and a second section 3160. As discussed above, the second section 3160 may include a sealing flange 3110 and may include a support flange 3120. Again, the patient interface may be formed in such a way that no section of the thermo-formable section 3150 is exposed to ambient, but the thermo-formable section 3150 is completely enclosed by the shell 3250 (at the connection points) and by the second section 3160 of the seal forming structure 3100.

(80) In this embodiment, the thermo-formable section is not connected or bonded to the shell 3250 (or substrate) around the entire perimeter, but only in selected locations, e.g., at the web portions 3154. This may improve the forming range of the user formable seal forming structure 3100. In other words, the thermo-formable section 3150, which may also be fin-shaped, may protrude further away from the shell 3250, thereby adding additional degrees of freedom to the shaping. As discussed, the perimeter section 3150 may be in the shape of a fin, however, it may also take another shape and be referred to as a frame or stiffener portion 3152. In the cross sectional view of FIG. 7b, it can be seen that in the lower half of this cross sectional view, there is no direct connection between the thermo-formable section 3150 and the shell or substrate 3250. Instead, the gap G of FIG. 7b is filled with the material of the second section 3160, such as silicon, during the over molding process, resulting in a larger extension of the second section 3160 contributing to a larger adjustment range.

(81) FIGS. 8a and 8b show another embodiment of the present technology, FIG. 8b being an enlarged view of a detail of FIG. 8a. Again, the patient interface 3000 of this embodiment includes a shell or chassis 3250 with a connection port 3600. Furthermore, the patient interface 3000 also includes a seal forming structure 3100, which may include a sealing flange 3110 and which may also include a support flange 3120, as discussed above (although these structures do not necessarily need to be provided).

(82) Furthermore, the seal forming structure 3100 includes a pocket or groove 3130 adapted for receiving a thermo-formable section 3150. Generally, the shell 3250 and the seal forming structure 3100 define together a plenum chamber 3200. During use, seal forming structure 3100 and shell 3250 limit, together with a patient's face, a certain space, that is the plenum chamber 3200. This section may also be referred to as the interior of the patient interface. Conversely thereto, there is also an exterior 3270 of the patient interface 3000. That is the space other the space delimited, during use, by the patient interface 3000 and the patient. Preferably, the groove or pocket 3130 is only accessibly from the patient interface's outside 3270. In other words, the pocket or groove 3130 is provided on the outside 3250 of the patient interface 3000. As depicted in FIG. 8b the groove 3130 may be provided with at least one undercut 3132 and preferably a plurality of undercuts 3132, that is, e.g., two undercuts 3132, forming a mechanical interlock feature to prevent the thermo-formable section 3135 from coming loose during forming. Alternatively or in addition, a chemical bond can be formed between the thermo-formable section 3150 and the groove 3130.

(83) For production of this embodiment of the present technology, the shell or chassis 3250 and the section 3160 of the seal forming structure 3100 are molded in a two component molding process in such a way that the seal forming structure 3100 includes the groove or pocket 3130 into which thermo-formable material is introduced at a second stage after the molding, e.g., by means of potting and/or dosing processes. Again, the section 3160 of the sealing structure may be silicon and the thermo-formable material may be polycaprolactone (PCL).

(84) This embodiment allows for an alternative manufacturing process, which is particularly easy and allows a simple introduction of the thermo-formable section 3130.

(85) A still further embodiment of a patient interface 3000 of the present technology, as well as a corresponding manufacturing process, are depicted in FIGS. 9a and 9b. FIG. 9a depicts a manufacturing tool, such as a molding tool with two sections A and B. One of the two sections A and B is a movable section, while the other section is a fixed section of the tool. For example, section B may be a fixed tool section and section A may be a movable tool section. In this tool, there is placed an insert for a shell 3250 of the patient interface 3000 having a connection portion 3600. Furthermore, there is also placed an insert for the seal forming structure 3100 in this tool. Furthermore, an insert of thermo-formable material 3150 is also placed in this tool. Near and around the insert for the thermo-formable section 3150, there is provided a gap of cavity 3174. In particular, the insert for the seal forming structure 3100 may include a pocket or cavity 3130 into which the insert of thermo-formable material 3150 is placed.

(86) The thermo-formable material 3150 may be cast, pointed or dosed or molded into the groove 3130 or assembled as a separate component thereof. The resulting two-component-structure may be inserted into the tool A-B, together with the insert for the shell or chassis 3250. All these components may then be over molded in another step to complete the assembly. That is, a further material, such as silicon, is introduced to fill the cavity 3174 to connect the components with each other, so that the seal forming structure 3100, the thermo-formable material 3150, and the shell 3250, which form a resulting patient interface 3000, are integrally formed. The seal forming structure 3100, the thermo-formable material 3150, and the shell 3250 are permanently fixed in this one piece construction.

(87) A resulting patient interface 3000 is depicted in cross section in FIG. 9b. Again, this patient interface includes a shell or chassis 3250 with a connection port 3600, as well as a seal forming structure 3100, which may (or may not) comprise at least one of a sealing flange 3110 and a support flange 3120. Furthermore, the seal forming structure 3100 comprises a thermo-formable section 3150 and a second section 3160 of another material. The second section 3160 includes a first sub section 3162 and a second sub section 3164. Again, this second section may include the sealing flange 3110 and the support flange 3120. Furthermore, the seal forming structure 3100 of this embodiment also includes the second sub section 3164 integrally connecting the seal forming structure 3100 to the shell 3250. However, even though the structure 3160 is depicted to be a structure separate from the connecting structure 3164 of seal forming structure 3100, these sections may be made of the same material, such as silicon. However, alternatively, these sections may also be made from different materials.

(88) This embodiment may allow for still another manufacturing process and a simple molding process, as well as simplicity of tooling.

4.5 Glossary

(89) For the purposes of the present technology disclosure, in certain forms of the present technology, one or more of the following definitions may apply. In other forms of the present technology, alternative definitions may apply.

(90) 4.5.1 General

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

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

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

(94) In another example, pressure may be the pressure immediately surrounding or external to the body.

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

(96) Continuous Positive Airway Pressure (CPAP) therapy: CPAP therapy will be taken to mean the application of a supply of air to an entrance to the airways at a pressure that is continuously positive with respect to atmosphere. The pressure may be approximately constant through a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the pressure will vary between different respiratory cycles of the patient, for example, being increased in response to detection of indications of partial upper airway obstruction, and decreased in the absence of indications of partial upper airway obstruction.

(97) Patient: A person, whether or not they are suffering from a respiratory disease.

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

(99) 4.5.2 Aspects of the Respiratory Cycle

(100) Apnea: According to some definitions, an apnea is said to have occurred when flow falls below a predetermined threshold for a duration, e.g. 10 seconds. An obstructive apnea will be said to have occurred when, despite patient effort, some obstruction of the airway does not allow air to flow. A central apnea will be said to have occurred when an apnea is detected that is due to a reduction in breathing effort, or the absence of breathing effort, despite the airway being patent. A mixed apnea occurs when a reduction or absence of breathing effort coincides with an obstructed airway.

(101) Breathing rate: The rate of spontaneous respiration of a patient, usually measured in breaths per minute.

(102) Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

(103) Effort (breathing): Breathing effort will be said to be the work done by a spontaneously breathing person attempting to breathe.

(104) Expiratory portion of a breathing cycle: The period from the start of expiratory flow to the start of inspiratory flow.

(105) Flow limitation: Flow limitation will be taken to be the state of affairs in a patient's respiration where an increase in effort by the patient does not give rise to a corresponding increase in flow. Where flow limitation occurs during an inspiratory portion of the breathing cycle it may be described as inspiratory flow limitation. Where flow limitation occurs during an expiratory portion of the breathing cycle it may be described as expiratory flow limitation.

(106) Types of flow limited inspiratory waveforms:

(107) (i) Flattened: Having a rise followed by a relatively flat portion, followed by a fall.

(108) (ii) M-shaped: Having two local peaks, one at the leading edge, and one at the trailing edge, and a relatively flat portion between the two peaks.

(109) (iii) Chair-shaped: Having a single local peak, the peak being at the leading edge, followed by a relatively flat portion.

(110) (iv) Reverse-chair shaped: Having a relatively flat portion followed by single local peak, the peak being at the trailing edge.

(111) Hypopnea: Preferably, a hypopnea will be taken to be a reduction in flow, but not a cessation of flow. In one form, a hypopnea may be said to have occurred when there is a reduction in flow below a threshold rate for a duration. A central hypopnea will be said to have occurred when a hypopnea is detected that is due to a reduction in breathing effort. In one form in adults, either of the following may be regarded as being hypopneas: (i) a 30% reduction in patient breathing for at least 10 seconds plus an associated 4% desaturation; or (ii) a reduction in patient breathing (but less than 50%) for at least 10 seconds, with an associated desaturation of at least 3% or an arousal.

(112) Hyperpnea: An increase in flow to a level higher than normal flow rate.

(113) Inspiratory portion of a breathing cycle: The period from the start of inspiratory flow to the start of expiratory flow will be taken to be the inspiratory portion of a breathing cycle.

(114) Patency (airway): The degree of the airway being open, or the extent to which the airway is open. A patent airway is open. Airway patency may be quantified, for example with a value of one (1) being patent, and a value of zero (0), being closed (obstructed).

(115) Positive End-Expiratory Pressure (PEEP): The pressure above atmosphere in the lungs that exists at the end of expiration.

(116) Peak flow rate (Qpeak): The maximum value of flow rate during the inspiratory portion of the respiratory flow waveform.

(117) Respiratory flow rate, airflow rate, patient airflow rate, respiratory airflow rate (Qr): These synonymous terms may be understood to refer to the RPT device's estimate of respiratory airflow rate, as opposed to “true respiratory flow” or “true respiratory airflow”, which is the actual respiratory flow rate experienced by the patient, usually expressed in litres per minute.

(118) Tidal volume (Vt): The volume of air inhaled or exhaled during normal breathing, when extra effort is not applied.

(119) (inhalation) Time (Ti): The duration of the inspiratory portion of the respiratory flow rate waveform.

(120) (exhalation) Time (Te): The duration of the expiratory portion of the respiratory flow rate waveform.

(121) (total) Time (Ttot): The total duration between the start of the inspiratory portion of one respiratory flow rate waveform and the start of the inspiratory portion of the following respiratory flow rate waveform.

(122) Typical recent ventilation: The value of ventilation around which recent values over some predetermined timescale tend to cluster, that is, a measure of the central tendency of the recent values of ventilation.

(123) Upper airway obstruction (UAO): includes both partial and total upper airway obstruction. This may be associated with a state of flow limitation, in which the level of flow increases only slightly or may even decrease as the pressure difference across the upper airway increases (Starling resistor behaviour).

(124) Ventilation (Vent): A measure of the total amount of gas being exchanged by the patient's respiratory system. Measures of ventilation may include one or both of inspiratory and expiratory flow, per unit time. When expressed as a volume per minute, this quantity is often referred to as “minute ventilation”. Minute ventilation is sometimes given simply as a volume, understood to be the volume per minute.

(125) 4.5.3 Anatomy of the Face

(126) Ala: the external outer wall or “wing” of each nostril (plural: alar)

(127) Alare: The most lateral point on the nasal ala.

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

(129) Auricle: The whole external visible part of the ear.

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

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

(132) Columella: the strip of skin that separates the nares and which runs from the pronasale to the upper lip.

(133) Columella angle: The angle between the line drawn through the midpoint of the nostril aperture and a line drawn perpendicular to the Frankfurt horizontal while intersecting subnasale.

(134) Frankfort horizontal plane: A line extending from the most inferior point of the orbital margin to the left tragion. The tragion is the deepest point in the notch superior to the tragus of the auricle.

(135) Glabella: Located on the soft tissue, the most prominent point in the midsagittal plane of the forehead.

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

(137) Lip, lower (labrale inferius):

(138) Lip, upper (labrale superius):

(139) Greater alar cartilage: A plate of cartilage lying below the lateral nasal cartilage. It is curved around the anterior part of the naris. Its posterior end is connected to the frontal process of the maxilla by a tough fibrous membrane containing three or four minor cartilages of the ala.

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

(141) Naso-labial sulcus or Naso-labial fold: The skin fold or groove that runs from each side of the nose to the corners of the mouth, separating the cheeks from the upper lip.

(142) Naso-labial angle: The angle between the columella and the upper lip, while intersecting subnasale.

(143) Otobasion inferior: The lowest point of attachment of the auricle to the skin of the face.

(144) Otobasion superior: The highest point of attachment of the auricle to the skin of the face.

(145) Pronasale: the most protruded point or tip of the nose, which can be identified in lateral view of the rest of the portion of the head.

(146) Philtrum: the midline groove that runs from lower border of the nasal septum to the top of the lip in the upper lip region.

(147) Pogonion: Located on the soft tissue, the most anterior midpoint of the chin.

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

(149) Sagittal plane: A vertical plane that passes from anterior (front) to posterior (rear) dividing the body into right and left halves.

(150) Sellion: Located on the soft tissue, the most concave point overlying the area of the frontonasal suture.

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

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

(153) Subnasal point: Located on the soft tissue, the point at which the columella merges with the upper lip in the midsagittal plane.

(154) Supramentale: The point of greatest concavity in the midline of the lower lip between labrale inferius and soft tissue pogonion

(155) 4.5.4 Anatomy of the Skull

(156) Frontal bone: The frontal bone includes a large vertical portion, the squama frontalis, corresponding to the region known as the forehead.

(157) Mandible: The mandible forms the lower jaw. The mental protuberance is the bony protuberance of the jaw that forms the chin.

(158) Maxilla: The maxilla forms the upper jaw and is located above the mandible and below the orbits. The frontal process of the maxilla projects upwards by the side of the nose, and forms part of its lateral boundary.

(159) Nasal bones: The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, the “bridge” of the nose.

(160) Nasion: The intersection of the frontal bone and the two nasal bones, a depressed area directly between the eyes and superior to the bridge of the nose.

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

(162) Orbit: The bony cavity in the skull to contain the eyeball.

(163) Parietal bones: The parietal bones are the bones that, when joined together, form the roof and sides of the cranium.

(164) Temporal bones: The temporal bones are situated on the bases and sides of the skull, and support that part of the face known as the temple.

(165) Zygomatic bones: The face includes two zygomatic bones, located in the upper and lateral parts of the face and forming the prominence of the cheek.

(166) 4.5.5 Anatomy of the Respiratory System

(167) Diaphragm: A sheet of muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity, containing the heart, lungs and ribs, from the abdominal cavity. As the diaphragm contracts the volume of the thoracic cavity increases and air is drawn into the lungs.

(168) Larynx: The larynx, or voice box houses the vocal folds and connects the inferior part of the pharynx (hypopharynx) with the trachea.

(169) Lungs: The organs of respiration in humans. The conducting zone of the lungs contains the trachea, the bronchi, the bronchioles, and the terminal bronchioles. The respiratory zone contains the respiratory bronchioles, the alveolar ducts, and the alveoli.

(170) Nasal cavity: The nasal cavity (or nasal fossa) is a large air filled space above and behind the nose in the middle of the face. The nasal cavity is divided in two by a vertical fin called the nasal septum. On the sides of the nasal cavity are three horizontal outgrowths called nasal conchae (singular “concha”) or turbinates. To the front of the nasal cavity is the nose, while the back blends, via the choanae, into the nasopharynx.

(171) Pharynx: The part of the throat situated immediately inferior to (below) the nasal cavity, and superior to the oesophagus and larynx. The pharynx is conventionally divided into three sections: the nasopharynx (epipharynx) (the nasal part of the pharynx), the oropharynx (mesopharynx) (the oral part of the pharynx), and the laryngopharynx (hypopharynx).

(172) 4.5.6 Materials

(173) Silicone or Silicone Elastomer: A synthetic rubber. In this specification, a reference to silicone may be a reference to liquid silicone rubber (LSR) or a compression moulded silicone rubber (CMSR). One form of commercially available LSR is SILASTIC (included in the range of products sold under this trademark), manufactured by Dow Corning. Another manufacturer of LSR is Wacker. Unless otherwise specified to the contrary, an exemplary form of LSR has a Shore A (or Type A) indentation hardness in the range of about 35 to about 45 as measured using ASTM D2240.

(174) Polycarbonate: a typically transparent thermoplastic polymer of Bisphenol-A Carbonate.

(175) 4.5.7 Aspects of a Patient Interface

(176) Anti-asphyxia valve (AAV): The component or sub-assembly of a mask system that, by opening to atmosphere in a failsafe manner, reduces the risk of excessive CO.sub.2 rebreathing by a patient.

(177) Elbow: A conduit that directs an axis of flow of air to change direction through an angle. In one form, the angle may be approximately 90 degrees. In another form, the angle may be less than 90 degrees. The conduit may have an approximately circular cross-section. In another form the conduit may have an oval or a rectangular cross-section.

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

(179) Headgear: Headgear will be taken to mean a form of positioning and stabilizing structure designed for use on a head. Preferably the headgear comprises a collection of one or more struts, ties and stiffeners configured to locate and retain a patient interface in position on a patient's face for delivery of respiratory therapy. Some ties are formed of a soft, flexible, elastic material such as a laminated composite of foam and fabric.

(180) Membrane: Membrane will be taken to mean a typically thin element that has, preferably, substantially no resistance to bending, but has resistance to being stretched.

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

(182) Seal: The noun form (“a seal”) will be taken to mean a structure or barrier that intentionally resists the flow of air through the interface of two surfaces. The verb form (“to seal”) will be taken to mean to resist a flow of air.

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

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

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

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

(187) Tie: A tie will be taken to be a structural component designed to resist tension.

(188) Vent: (noun) the structure that allows an intentional flow of air from an interior of the mask, or conduit to ambient air, e.g. to allow washout of exhaled gases.

(189) 4.5.8 Terms Used in Relation to Patient Interface

(190) Curvature (of a surface): A region of a surface having a saddle shape, which curves up in one direction and curves down in a different direction, will be said to have a negative curvature. A region of a surface having a dome shape, which curves the same way in two principal directions, will be said to have a positive curvature. A flat surface will be taken to have zero curvature.

(191) Floppy: A quality of a material, structure or composite that is one or more of: Readily conforming to finger pressure. Unable to retain its shape when caused to support its own weight. Not rigid. Able to be stretched or bent elastically with little effort.

(192) The quality of being floppy may have an associated direction, hence a particular material, structure or composite may be floppy in a first direction, but stiff or rigid in a second direction, for example a second direction that is orthogonal to the first direction.

(193) Resilient: Able to deform substantially elastically, and to release substantially all of the energy upon unloading, within a relatively short period of time such as 1 second.

(194) Rigid: Not readily deforming to finger pressure, and/or the tensions or loads typically encountered when setting up and maintaining a patient interface in sealing relationship with an entrance to a patient's airways.

(195) Semi-rigid: means being sufficiently rigid to not substantially distort under the effects of mechanical forces typically applied during respiratory pressure therapy.

4.6 Other Remarks

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

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

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

(199) Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this technology belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present technology, a limited number of the exemplary methods and materials are described herein.

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

(201) It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include their plural equivalents, unless the context clearly dictates otherwise.

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

(203) The terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

(204) Any relative term, such as “generally”, “substantially”, “about”, etc. preceding a respective feature should be understood to also encompass the respective features within its exact sense, unless stated otherwise. That is, e.g., “about 3 elements” also encompasses “(exactly) 3 elements” and “generally vertical” also encompasses “vertical”.

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

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

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