Abstract: An improved fresh gas device includes a gas mixer connected to a source of oxygen and to a source of at least one other gas for mixing oxygen to form a gas mixture to be supplied to a patient. A line bypasses the mixer and is provided with a switch for initiating pressure pulses in the bypass line and a pneumatically operated valve is provided downstream of the mixer and is controllable responsive to the pressure in the bypass line.

Abstract: An apparatus for wetting respiratory gas comprises a receiver having an interior wetting chamber and a cartridge receiving chamber which communicates at its lower end with the wetting chamber and which has an open end for receiving a heater cartridge. The heater cartridge is disposable in the cartridge receiving chamber and it includes an inner portion containing a heater element and an outer sleeve portion which has a lower end disposed in the wetting chamber and has side walls which are spaced from the wall of the inner portion of the cartridge containing the heater element. The receiver contains a duct for supplying water into the space between the sleeve and the inner portion of the cartridge containing the heater so that the water will be heated in its passage around the inner portion and may be discharged through openings at the lower end of the sleeve into the wetting chamber.