Mechanical External Cardiac Compression and Ventilation During Cardiopulmonary Resuscitation

Abstract

In 1962 Birch et al (1) varied the force, rate, and duration of systolic thrust during external cardiac compressions on Kenya baboons and mongrel dogs with ventricular fibrillation, using a mechanical device. They concluded that longer periods of chest compression per cycle and increasing rates and force of compression all increased perfusion within limits, as judged by arteriovenous pressure differences. The limits in dogs were 80 lb of force and a 0.25-second diastolic filling period. More force or shorter periods did not produce further augmentation of pressure differences. They suggested that the short systolic thrust so commonly used for external cardiac compressions should be abandoned in favor of a push-and-hold technique.