Successful resuscitation after prolonged periods of cardiac arrest: A new field in cardiac surgery

Abstract

Cardiopulmonary resuscitation is associated with high mortality and poor neurological recovery. Cardiopulmonary resuscitation can cause ischemia-reperfusion injury of the whole body and brain. We assessed the hypothesis that controlled reperfusion of the whole body with cardiopulmonary bypass would limit reperfusion injury after 15 minutes of normothermic cardiac arrest with better survival and neurological recovery. Eleven pigs were exposed to normothermic ischemia for 15 minutes by inducing ventricular fibrillation, followed by cardiopulmonary resuscitation (control group, n = 4) or 60 minutes of cardiopulmonary bypass (treatment group, n = 7). Conditions of reperfusion and the reperfusate were controlled with cardiopulmonary bypass. Animals were observed for up to 7 days, and neurological assessment (Neurological Deficit Score: 0, normal; 500, brain death), magnetic resonance imaging, and brain histology were performed. All animals in the control group died after 20 minutes of cardiopulmonary resuscitation (n = 4). All (n = 7) survived in the treatment group. Clinically apparent neurological recovery occurred within 24 hours; 1 fully conscious pig could not walk. The Neurological Deficit Score was 98 +/- 31 in all animals (n = 7) after 24 hours and decreased to 0 after 48 hours in 4 of 5 eligible animals; 1 animal had a Neurological Deficit Score of 110 after 3 days. Brain histology revealed hypoxic and apoptotic neurons with an inconclusive correlation regarding neurological recovery. Clinically apparent neurological recovery after a period of 15 minutes of cardiac arrest occurred with cardiopulmonary bypass instead of cardiopulmonary resuscitation for reperfusing the whole body. This approach contrasts with cardiopulmonary resuscitation, in which resuscitation has been reported as successful after only 3 to 5 minutes of cardiac arrest. Cardiopulmonary bypass might be a key to improve survival and neurological recovery after cardiac arrest.