Mask and vent assembly therefor

1. A method for attaching a removable, washout vent insert to a CPAP mask, the CPAP mask comprised of a shell having an inlet tube, the CPAP mask comprising polycarbonate material, the shell having only a single opening for purposes of CO 2 washout, the single opening being bounded by a rim of said polycarbonate material, the vent insert being made of a material more flexible than the polycarbonate material of the rim, the vent insert having a plurality of orifices to continuously exhaust CO 2 -laden gas from the CPAP mask during the entire breathing cycle of a patient while reducing noise generated by gas washout, the vent insert, in a cross-sectional view, having an inner flange and an outer flange, the inner and outer flanges defining a recess therebetween at a periphery of the vent insert, the method comprising:

squeezing the vent insert;

aligning the vent insert so it is oriented to match the shape of the single opening in the CPAP mask;

inserting the inner flange of the vent insert into the single opening; and

releasing the vent insert once the inner flange is within the single opening, the vent insert resiliently expanding to receive the rim in the recess, engage the inner flange with an inner surface of the rim, and engage the outer flange with an outer surface of the rim,

wherein an outer end of each orifice at an outer exit side of the insert is positioned outward of the outer surface of the rim,

wherein the recess of the vent insert and the single opening have non-circular, complementary shapes,

wherein a cross-sectional area of each orifice at an inner entry side of the vent insert is larger than a cross-sectional area of each orifice at the outer exit side of the vent insert, and

wherein the vent insert is insertable into the single opening in only a single orientation in which a smaller end of each orifice is positioned at the outer exit side of the vent insert.

2. The method of claim 1 , wherein the outer flange of the insert, as seen in cross-section, includes first and second flange portions on opposing sides of the insert to receive the rim on opposing sides of the single opening, and the first and second flange portions on each side of the insert extend a substantially equal distance from the single opening.

3. The method of claim 1 , wherein the vent insert is structured to continuously exhaust gas in the range of 4-18 cmH 2 O.

4. A method for attaching a washout vent insert to a CPAP mask, the CPAP mask comprised of a shell having an inlet tube, the CPAP mask having only a single opening for purposes of CO 2 washout, the single opening being bounded by a rim, the vent insert having a plurality of orifices to continuously exhaust CO 2 -laden gas from the CPAP mask during the entire breathing cycle of a patient, the vent insert structured and configured to reduce noise during gas washout, the vent insert having an inner flange and an outer flange, the inner and outer flanges defining a recess therebetween at a periphery of the vent insert, the method comprising:

squeezing the vent insert;

aligning the vent insert so it is oriented to match the shape of the single opening in the CPAP mask;

inserting the inner flange of the vent insert into the single opening; and

releasing the vent insert once the inner flange is within the single opening, the vent insert resiliently expanding to receive the rim in the recess, engage the inner flange with an inner surface of the rim, and engage the outer flange with an outer surface of the rim,

wherein the insert includes a main body and the inner and outer flanges are provided at the perimeter of the main body, the plurality of orifices are provided in the main body and the inner and outer flanges are radially outward of the plurality of orifices, and

wherein a cross sectional area of each orifice at an inner side of the vent insert is larger than a cross-sectional area of each orifice at an outer exit side of the vent insert, and the vent insert is insertable into the single opening in only a single orientation in which a smaller end of each orifice is positioned at the outer exit side of the vent insert.

5. The method of claim 4 , wherein each orifice in the vent insert is larger on an inside of the mask than on an outside of the mask.

6. The method of claim 4 , wherein squeezing the vent insert includes squeezing the vent insert about an axis that is substantially transverse to its longitudinal axis.

7. The method of claim 4 , wherein the vent insert resiliently expands from a squeezed position to receive the rim in the recess.

8. The method of claim 4 , wherein the inner flange of the vent insert is squeezed into the single opening, with the outer flange of the vent insert on top of the single opening, and part of the rim is received in the recess between the inner and outer flanges.

9. The method of claim 4 , wherein the vent insert includes an elongated, non-circular shape.

10. The method of claim 4 ,

wherein squeezing the vent insert includes squeezing the vent insert about an axis that is substantially transverse to its longitudinal axis,

wherein the vent insert resiliently expands from a squeezed position to receive the rim in the recess,

wherein the inner flange of the vent insert is squeezed into the single opening, with the outer flange of the vent insert on top of the single opening, and part of the rim is received in the recess between the inner and outer flanges, and

wherein the vent insert includes an elongated, non-circular shape.

11. The method of claim 4 , wherein the outer flange of the insert, as seen in cross-section, includes first and second flange portions on opposing sides of the insert to receive the rim on opposing sides of the single opening, and the first and second flange portions on each side of the insert extend a substantially equal distance from the single opening.

12. The method of claim 4 , wherein the vent insert is structured to continuously exhaust gas in the range of 4-18 cmH 2 O.

13. A method for attaching a washout vent insert to a CPAP mask, the CPAP mask comprised of a shell having an inlet tube, the CPAP mask comprising polycarbonate material, the shell having only a single opening for purposes of CO 2 washout, the single opening being bounded by a rim of said polycarbonate material, the vent insert constructed and arranged to be more flexible than the polycarbonate material of the rim, the vent insert having a plurality of orifices to continuously exhaust CO 2 -laden gas from the CPAP mask during the entire breathing cycle of a patient while reducing noise generated by gas washout, the vent insert, in a cross-sectional view, having an inner flange and an outer flange, the inner and outer flanges defining a recess therebetween at a periphery of the vent insert, the method comprising:

squeezing the vent insert;

aligning the vent insert so it is oriented to match the shape of the single opening in the CPAP mask;

inserting the inner flange of the vent insert into the single opening; and

releasing the vent insert once the inner flange is within the single opening, the vent insert resiliently expanding to receive the rim in the recess, engage the inner flange with an inner surface of the rim, and engage the outer flange with an outer surface of the rim,

wherein an outer end of each orifice at an outer side of the insert is positioned outward of the outer surface of the rim,

wherein the insert includes a main body and the inner and outer flanges are provided at the perimeter of the main body, the plurality of orifices are provided in the main body and the inner and outer flanges are radially outward of the plurality of orifices,

wherein the recess of the vent insert and the single opening have non-circular, complementary shapes, and

wherein a cross-sectional area of each orifice at an inner entry side of the vent insert is larger than a cross-sectional area of each orifice at an outer exit side of the vent insert, and the vent insert is insertable into the single opening in only a single orientation in which a smaller end of each orifice is positioned at the outer exit side of the vent insert.

14. The method of claim 13 , wherein the shell is formed from a relatively more rigid material and a region surrounding or adjacent the plurality of orifices is formed from a relatively more flexible material compared to the relatively more rigid material.

15. The method of claim 13 , wherein the outer flange of the insert, as seen in cross-section, includes first and second flange portions on opposing sides of the insert to receive the rim on opposing sides of the single opening, and the first and second flange portions on each side of the insert extend a substantially equal distance from the single opening.

16. The method of claim 13 , wherein the vent insert is structured to continuously exhaust gas in the range of 4-18 cmH 2 O.

17. A method for attaching a washout vent insert to a CPAP mask, the CPAP mask comprised of a main body having a shell having an inlet tube, the main body having only a single opening for purposes of CO 2 washout, the single opening being bounded by a rim, the vent insert having a plurality of orifices to continuously exhaust CO 2 -laden gas from the CPAP mask during the entire breathing cycle of a patient, the vent insert having an inner flange and an outer flange, the inner and outer flanges defining a recess therebetween at a periphery of the vent insert, the method comprising:

temporarily flexing or deforming the vent insert to allow the inner flange to enter into the single opening; and

releasing the vent insert once the inner flange is within the single opening to allow the vent insert to return to an unflexed or undeformed position to receive the rim in the recess, engage the inner flange with an inner surface of the rim, and engage the outer flange with an outer surface of the rim, thereby securing the vent insert relative to the rim,

wherein the recess of the vent insert and the single opening have non-circular, complementary shapes,

wherein the vent insert is structured and configured to reduce noise during gas washout,

wherein a cross-sectional area of each orifice at an inner entry side of the vent insert is larger than a cross-sectional area of each orifice at an outer exit side of the vent insert, and

wherein the vent insert is insertable into the single opening in only a single orientation in which a smaller end of each orifice is positioned at the outer exit side of the vent insert.

18. The method of claim 17 , wherein temporarily flexing or deforming the vent insert includes squeezing the vent insert.

19. The method of claim 18 , wherein squeezing the vent insert includes squeezing the vent insert about an axis that is substantially transverse to its longitudinal axis.

20. The method of claim 17 , further comprising aligning the vent insert so it is oriented to match the shape of the single opening.

21. The method of claim 17 , wherein the inner flange of the vent insert is squeezed into the single opening, with the outer flange of the vent insert on top of the single opening, and part of the rim is received in the recess between the inner and outer flanges.

22. The method of claim 17 , wherein temporarily flexing or deforming the vent insert includes squeezing the vent insert,

wherein squeezing the vent insert includes squeezing the vent insert about an axis that is substantially transverse to its longitudinal axis,

further comprising aligning the vent insert so it is oriented to match the shape of the single opening, and

wherein the inner flange of the vent insert is squeezed into the single opening, with the outer flange of the vent insert on top of the single opening, and part of the rim is received in the recess between the inner and outer flanges.

23. The method of claim 17 , wherein the outer flange of the insert, as seen in cross-section, includes first and second flange portions on opposing sides of the insert to receive the rim on opposing sides of the single opening, and the first and second flange portions on each side of the insert extend a substantially equal distance from the single opening.

24. The method of claim 17 , wherein the vent insert is structured to continuously exhaust gas in the range of 4-18 cmH 2 O.