Patent ID: 8826910

Claim:
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.