Breathing assistance apparatus

1. A breathing assistance apparatus comprising:

a mask body adapted to cover a nose and a mouth of a patient; and

a mask cushion configured to contact facial contours of the patient, the mask cushion being a single wall membrane having an apex, the mask cushion comprising:

a cushion base coupled to a periphery of the mask body;

a side wall that extends from the cushion base and that defines a periphery of the mask cushion; and

a lip defining a patient-contacting surface that surrounds an opening configured to receive the nose and the mouth of the patient, the opening having an uppermost extent and a lowermost extent;

wherein the lip of the mask cushion comprises an upper thin region and a lower thin region that are separated from one another by portions of the mask cushion having a greater thickness, each of the upper thin region and the lower thin region having a smaller thickness than adjacent portions of the lip, wherein the upper thin region has at least a portion that is located above the opening at the apex and wherein the lower thin region has at least a portion that is located below the opening and defines a portion of the lowermost extent of the opening;

wherein the lower thin region defines a variable width;

wherein the upper thin region is configured to rest against a nasal bridge of the patient and the lower thin region is configured to rest against a chin of the patient;

wherein the lip of the mask cushion further comprises a pair of side thin regions, each of the pair of side thin regions extends along a respective side of the lip adjacent the opening and terminates at a location spaced above the lowermost extent of the opening such that only a portion of the opening within the respective sides of the lip is defined by the pair of side thin regions;

wherein each of the pair of side thin regions extends only partially across a lateral surface of the respective side of the lip such that the lip defines a relatively thicker laterally outward region located laterally outward of each of the pair of side thin regions; and

wherein each of the pair of side thin regions are located between the upper thin region and the lower thin region.

2. The breathing assistance apparatus of claim 1 , wherein the lower thin region extends to a lower edge of the lip.

3. The breathing assistance apparatus of claim 1 , wherein the width of the lower thin region increases in a direction from the lowermost extent of the opening to a lower edge of the lip.

4. The breathing assistance apparatus of claim 1 , wherein the upper thin region is arcuate in shape.

5. The breathing assistance apparatus of claim 1 , wherein a thickness of the lip in the thin region is between 0.2 mm and 0.3 mm.

6. The breathing assistance apparatus of claim 5 , wherein a thickness of at least a portion of the lip outside of the thin region is 1.0 mm.

7. The breathing assistance apparatus of claim 1 , wherein each of the pair of side thin regions extend from the upper thin region.

8. The breathing assistance apparatus of claim 1 , wherein the mask body is molded from polycarbonate.

9. The breathing assistance apparatus of claim 8 , wherein the mask cushion is made of silicone.

10. The breathing assistance apparatus of claim 1 , wherein the upper thin region is more flexible and configured to be collapsible to a greater degree when a force is placed against the mask cushion relative to other portions of the mask cushion.

11. A breathing assistance apparatus comprising:

a mask body adapted to cover a nose and a mouth of a patient; and

a cushion configured to contact facial contours of the patient, the cushion being a single wall membrane having an apex, the cushion comprising:

a cushion base coupled to a periphery of the mask body;

a side wall that extends from the cushion base and that defines a periphery of the cushion; and

a lip defining a patient-contacting surface that surrounds an opening configured to receive the nose and the mouth of the patient, the opening having an uppermost extent;

wherein the lip of the cushion comprises a thin region positioned at the apex, the thin region having a smaller thickness than adjacent portions of the lip, wherein a width of the thin region tapers inward between an upper edge of the lip and the uppermost extent of the opening; and

wherein the thin region comprises an upper thin region and a lower thin region that are separated from one another by portions of the cushion having a greater thickness, and wherein the lower thin region is configured to rest against a chin of a patient.

12. The breathing assistance apparatus of claim 11 , wherein the thin region extends all the way to, and defines a portion of, a periphery of the opening.

13. The breathing assistance apparatus of claim 12 , wherein each side of the thin region intersects the opening below the uppermost extent.

14. The breathing assistance apparatus of claim 11 , wherein a thickness of the lip in the thin region is between 0.2 mm and 0.3 mm.

15. The breathing assistance apparatus of claim 14 , wherein a thickness of at least a portion of the lip outside of the thin region is 1.0 mm.

16. The breathing assistance apparatus of claim 11 , wherein the mask body is molded from polycarbonate.

17. The breathing assistance apparatus of claim 16 , wherein the cushion is made of silicone.

18. The breathing assistance apparatus of claim 11 , wherein the thin region is more flexible and configured to be collapsible to a greater degree when a force is placed against the cushion relative to other portions of the cushion.