Cuff pressure regulator for endotracheal-tube cuff

Claim 1

A cuff pressure regulator for controlling the pressure applied by the cuff of an endotracheal tube to the inner wall of the trachea, comprising a first chamber including means for the connection thereof to a pressurized gas supply source; a second chamber adapted to be connected to the cuff of the endotracheal tube, said second chamber having an orifice therein for venting said second chamber to the outisde of said regulator; a third chamber, said third chamber having means for maintaining the pressure therein at the same pressure as that surrounding said cuff; pressure regulating valve means interposed between said first and second chambers for controlling the flow of gas therebetween; valve driving means separating said second and third chambers and being connected to said pressure regulating valve means, said valve driving means displacing said pressure regulating valve means in response to a pressure difference between said second and third chambers, said pressure regulating valve means being opened by said valve driving means when the pressure in said second chamber is lower than a predetermined cuff pressure and closed when the pressure in said second chamber reaches said predetermined pressure; and pressure setting means connected to said valve driving means for setting said predetermined cuff pressure at which opening and closing of said pressure regulating valve means is initiated, whereby gas having a pressure higher than said predetermined cuff pressure is supplied from the pressurized gas supply source to said first chamber; and flow controlling valve means for controlling the flow of gas through the orifice in said second chamber, said means allowing the gas to slowly discharge through said orifice when the cuff pressure is being maintained at said predetermined cuff pressure and preventing discharge of gas through said orifice when the gas pressure in said first chamber falls below said predetermined cuff pressure.