Open chest versus closed chest cardiac resuscitation

Abstract

1. 1. External defibrillation was attempted in experiments on forty-one dogs. In all instances the heart could be readily defibrillated, as indicated by the electrocardiogram. However, a return of pulse and blood pressure seldom occurred beyond a fifty-second time limit. 2. 2. In experiments on seventy dogs the heart was permitted to fibrillate for 120 seconds before a countershock was directly applied. Electrical defibrillation promptly occurred but there was no return of systemic blood pressure. Following immediate massage there was a quick return of a coordinated beat and a normal blood pressure. 3. 3. In experiments on eighty-three dogs the heart was allowed to fibrillate for 120 seconds; then ventilation and massage were instituted before a direct countershock was applied to the ventricles. This was followed in each case by normal circulation and eighty-three survivals. 4. 4. For successful cardiac resuscitation, the re-establishment of the oxygen system is the primary act and the restoration of the heart beat is secondary. 5. 5. It appears that it is a minor problem to defibrillate the heart through an intact chest. However, to restore the life functions of an animal after some fifty seconds, supplemental measures have to be taken such as cardiac massage, or intra-arterial transfusion or infusion. 6. 6. Under ideal circumstances, when a trained team and equipment are in readiness in a room, a few seconds spent on external countershocking might be conceivable. We are carrying out additional studies continuously.