A portable pneumatic pump for external cardiac massage has been described. The apparatus is easy to operate, involving only three maneuvers, namely, opening the gas valve, connecting the hose to the gas source, and turning the rate regulator to the desired speed. A two-transistor rate circuit controls a small relay which energizes the solenoid of the valve. A small 30 volt battery powers the transistors while a larger lantern battery is used for the solenoid. The control circuit may be bypassed by means of a switching jack, and the solenoid valve controlled externally for synchronization of the R wave. The apparatus has maintained adequate circulation so that dogs in ventricular fibrillation for 30-minute periods were easily restored to good health by external countershock. Arterial pressures were recorded in 3 recently deceased persons. Further experimental and clinical studies are being conducted to elucidate those circulatory and respiratory factors which will make external cardiac massage most likely to succeed.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine