Isolation valve

An isolation valve assembly for use in administering mouth-to-mouth emergency artificial respiration comprising:

• a housing assembly comprising an inlet member having a first cylindrical wall portion and an inlet pipe extending therefrom having an inside first diameter, and an outlet member having a second cylindrical wall portion with a plurality of exhaust ports therethrough and an outlet pipe extending therefrom having an inside second diameter, said first and second cylindrical wall portions being matingly engaged to define an interior chamber having a third diameter, which is greater than either said first or said second diameter,
• a flexible diaphragm secured across said interior chamber, said diaphragm having a one-way valve therein for allowing gas to pass only from said inlet member to said outlet member and sealing means for forming a gas tight seal against said outlet member and closing said exhaust ports when gas is directed through said one-way valve, and
• a cylindrical filter member spaced apart from said inlet pipe and secured in and extending across said interior chamber between said inlet pipe and said diaphragm, said filter member having a diameter greater than the inside diameter of either said inlet pipe or said outlet pipe, wherein said valve assembly has a back pressure of less than about 6 cm H.sub.2 O at a flow of 50 liters per minute.