Patient interface

1. A patient interface comprising:

a plenum chamber pressurisable to a therapeutic pressure of at least 6 cmH2O above ambient air pressure, said plenum chamber including a plenum chamber inlet port sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient;

a first seal-forming structure constructed and arranged to form a seal with a region of the patient's face surrounding an entrance to the patient's mouth such that the flow of air at said therapeutic pressure is delivered to the mouth, the first seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use;

a second seal-forming structure constructed and arranged to form a seal with a region of the patient's face surrounding an entrance to the patient's nose such that the flow of air at said therapeutic pressure is delivered to the patient's nose, the second seal-forming structure constructed and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; and

a vent structure to allow a continuous flow of gases exhaled by the patient from an interior of the plenum chamber to vent to ambient, said vent structure being sized and shaped to maintain the therapeutic pressure in the plenum chamber in use;

the patent interface further comprising:

a pair of spaced apart support portions provided within the plenum chamber on opposite sides of the patient interface between the second seal forming structure and an anterior wall of the plenum chamber, each support portion comprising a superior face portion and an inferior face portion that are disposed within the plenum chamber, the superior face portion being spaced apart from the first seal-forming structure and the second seal-forming structure, wherein the support portions are configured to oppose compression in an anterior-posterior direction, and wherein the support portions are provided to portions of the second seal forming structure which are configured to seal, in use, against the patient's lip superior.

2. The patient interface of claim 1 , wherein each support portion comprises a strut.

3. The patient interface of claim 1 , wherein the support portions are connected to portions of the second seal forming structure which, in use, seal to the patient's lip superior, directly inferior to the lower corners of the patient's nose.

4. The patient interface of claim 1 , wherein the support portions are curved when viewed in a cross-section parallel to a sagittal plane.

5. The patient interface of claim 1 , wherein the support portions are curved when viewed in a cross-section parallel to a frontal plane.

6. The patient interface of claim 1 , wherein the plenum chamber comprises an oral portion and a nasal portion.

7. The patient interface of claim 6 , wherein each support portion is connected to the oral portion of the plenum chamber adjacent a boundary of a lateral side wall portion of the oral portion and a lateral side wall portion of the nasal portion.

8. The patient interface of claim 6 , wherein each support portion is connected to the oral portion of the plenum chamber adjacent a boundary of an anterior wall portion of the oral portion and an anterior wall portion of the nasal portion.

9. The patient interface of claim 6 , wherein lateral side wall portions of the plenum chamber curve inwardly adjacent a boundary with the nasal portion, wherein each support portion is substantially contiguous with an adjacent lateral side wall portion.

10. The patient interface of claim 1 , wherein the patient interface further comprises a positioning and stabilising structure configured to generate a force to hold the seal-forming structure in a therapeutically effective position on the patient's head.

11. The patient interface of claim 1 , wherein posterior surfaces of lateral portions of the second seal forming structure slope in a superior-anterior direction from a boundary of the first and second seal forming structures.

12. The patient interface of claim 1 , wherein a boundary between the first seal-forming structure and the second seal-forming structure comprises a ridge.

13. The patient interface of claim 12 , wherein:

the ridge has a radius of curvature of less than 2 mm; and

the ridge forms an angle between the first seal-forming structure and the second seal-forming structure, the angle is between about 20 degrees and about 90 degrees.

14. The patient interface of claim 12 , wherein the ridge extends across substantially an entire boundary between the first seal forming structure and the second seal forming structure.

15. The patient interface of claim 1 , wherein:

the first seal-forming structure is connected to an oral portion of the plenum chamber;

the second seal-forming structure connected to a nasal portion of the plenum chamber; and

at least a portion of the oral portion of plenum chamber comprises a flexible shell, wherein the flexible shell is formed from a material having a Young's modulus of less than 0.4 GPa; and wherein

at least one component is releasably connected to the flexible shell, wherein the at least one component is stiffer than a portion of the flexible shell adjacent the at least one component,

wherein the plenum chamber is at least partially formed by a shell and the vent structure is provided to the shell.

16. The patient interface of claim 15 , wherein the at least one component comprises one or more of: a vent module; a headgear connector; a headgear connector connected to a rigidizing arm; a rigidizing member; a less flexible shell portion.

17. The patient interface of claim 1 , wherein each support portion of the pair of support portions is directly connected to the second seal forming structure and the anterior wall of the plenum chamber.

18. The patient interface of claim 1 , wherein at least a portion of each of the pair of support portions is disposed inferior to a nasal aperture of the second seal forming structure, the inferior direction extending perpendicular to the anterior-posterior direction.

19. The patient interface of claim 1 , wherein the portions of the second seal forming structure are configured to contact the patient proximate to entrances to the nares where the ala meets the area above the lip superior.

20. The patient interface of claim 1 , wherein the support portions extend radially inwardly within the plenum chamber towards one another from opposite sides of the patent interface.

21. The patient interface of claim 1 , wherein the superior face portion is disposed between the first seal-forming structure and the second seal-forming structure.