Patent ID: 8122886

Claim:
A CPAP mask assembly for use with a system for supplying breathable gas pressurized above atmospheric pressure to a user for treatment of obstructive sleep apnea, the CPAP mask assembly comprising: a mask having an inlet tube that is, in use, adapted to be in fluid communication with a gas supply conduit, said mask including a shell made from polycarbonate or another rigid plastic material, the shell being provided with a sealing membrane to provide a gas tight seal with the user in use; and a vent including a plurality of gas washout orifices regularly separated and spaced from one another, each said orifice having an inner side that, in use, is positioned towards the user's face, and an outer side that, in use, is positioned adjacent atmosphere, each said orifice being open in use at least during the inhalation and exhalation phases of the user's breathing cycle, wherein the vent includes an insert and the orifices are provided in the insert, wherein the use of the insert in the mask reduces the decibel noise levels 1 meter from the mask.