Respiratory mask having gas washout vent and gas washout vent assembly for a respiratory mask

Abstract

The present invention provides a vent assembly suitable for use with a respiratory mask of the type used in CPAP treatment. In one embodiment the vent is made of a thin air permeable membrane. Generally, the membrane is thinner than 0.5 mm. The membrane can be made of a hydrophobic material such as polytetrafluoroethylene (PTFE). The membrane can also be fabricated from expanded PTFE. The expanded PTFE membrane is mounted on a polypropylene scrim. The pores of the membrane have a reference pore size of 10 to 15 microns. In an alternative embodiment, the vent assembly includes a vent constructed from stainless steel. In another embodiment the membrane has a superficial cross-sectional area of approximately 500 mm 2 . In another embodiment the vent assembly comprises a membrane attached to a vent frame, the vent assembly forming an insert which can be removeably attached to a mask fame.

1 - 14 . (canceled) 
     
     
         15 . A respiratory mask, the respiratory mask comprising:
 a shell including a breathable gas inlet adapted to connect to a breathable gas supply conduit;   a seal provided to the shell and adapted to interface with a patient's nose and/or mouth; and   a gas washout vent including an air permeable member, wherein the member is constructed from an expanded polytetrafluoroethylene material.   
     
     
         16 . A respiratory mask according to  claim 15 , wherein the material is auxetic. 
     
     
         17 . A respiratory mask according to  claim 15 , wherein the gas washout vent is provided to the shell. 
     
     
         18 . A respiratory mask according to  claim 17 , wherein the member is structured to extend across an opening provided in the shell. 
     
     
         19 . A respiratory mask according to  claim 15 , wherein the seal includes nasal prongs or nasal pillows. 
     
     
         20 . A respiratory mask according to  claim 15 , wherein a thickness of the member is less than a thickness of the shell. 
     
     
         21 . A respiratory mask according to  claim 15 , wherein the member includes a plurality of pores having a pore size in the range of 10-15 microns. 
     
     
         22 . A respiratory mask according to  claim 15 , wherein the member includes a thickness less than 0.5 mm. 
     
     
         23 . A respiratory mask according to  claim 15 , wherein the member is hydrophobic. 
     
     
         24 . A respiratory mask according to  claim 15 , further comprising a mask restraining strap provided to the shell and structured to maintain the mask adjacent to the patient's face. 
     
     
         25 . A respiratory mask according to  claim 15 , wherein the gas washout vent includes two members each provided to a respective side of the shell.