A gas-powered resuscitator is operable either in a manual mode or an automatic mode. The resuscitator includes an oscillatory timing valve (14) having an outlet (23) connected to a bi-stable valve (25), the operation of which is piloted by a manual valve (16). The outlet (26) of the bi-stable valve (25) connects to the outlet (2) of the resuscitator via a rotatable control (32) and a patient valve (41). The outlet (26) of the bi-stable valve (25) also connects to the control inlet (34) of the timing valve (14). The manual valve (16) has a button (62) that can be pushed down manually in the manual mode or can be held down in the automatic mode by rotating a locking ring (262). The maximum duration of cycles is limited by operation of the timing valve (14), whether the resuscitator is operated manually or automatically.

A demand valve resuscitator includes an inlet for connection to a pressurized source of breathable gas, such as oxygen, and an outlet for connection to a patient's airway. A normally-closed-pressure-actuated main valve is positioned between the inlet port and an inhalation chamber for controlling the demand mode of operation. A main valve controller operates the main valve in response to a reduced pressure in the inhalation chamber resulting from the commencement of spontaneous breathing by the patient. The manual operating mode, i.e., not dependent upon the patient breathing spontaneously, is controlled by a bypass valve which supplies gas to the patient independently of the main valve. A manually adjustable pressure relief valve sets the peak gas pressure. Another manual control permits the operator to preset the maximum opening of the bypass valve and therefore the flow rate of gas to the patient.

A manual resuscitator controls the portion of gas delivered from the ventilation bag to the patient responsive to which of a plurality of masks the ventilation bag is connected. Different sized masks deliver different portions of the gas from the ventilation bag as would be appropriate for a patient of a size associated with the mask. Emergency personnel, or others, need only couple the correct size mask to the ventilation bag, and the correct volume of gas is automatically delivered to the patient.

An apparatus meant for human use to supplement breathing while at high altitude in aircraft for emergency use. The apparatus includes a valve as an actuator to discharge oxygen into an attached facemask. A small cylinder containing oxygen under pressure is inserted and attached to the valve. Once assembled, the invention is stored in aircraft to be available for instant use. If a cabin depressurization emergency should occur, an occupant may access oxygen immediately by pressing a valve lever to start the flow of oxygen. By adjusting a knob located on the valve lever the user may control the flow of oxygen and extend oxygen use to allow time for evasive action.

A pressurized gas flow controlling microvalve having a casing and cap which together define a valve chamber having gas flow inlet and outlet ports and a plunger positioned within the valve chamber moveable from a closed position sealing the outlet port to an open position permitting gas to flow through the valve, the plunger having mounted thereon an O-ring which provides the seal for the outlet port.