Cardiopulmonary bypass after prolonged cardiac arrest in dogs

Abstract

Ventricular fibrillation (VF) cardiac arrest of more than ten minutes can be survived by cerebral neurons, but restoration of spontaneous circulation (ROSC) by external CPR is unreliable. Cardiopulmonary bypass (CPB) permits control of pressure, flow, oxygenation, temperature, and composition of blood. After 12 1/2 minutes of normothermic VF cardiac arrest, CPB was used as a research tool for reperfusion and assisted circulation for two hours in ten dogs without thoracotomy, with plasma substitute priming, and without preceding CPR (a deliberately nonclinical scenario). Recovery was compared with that in ten control dogs in which standard CPR with advanced life support (ALS) for up to 30 minutes was used to achieve ROSC. Both groups subsequently had blood pressure, blood gases, ventilation, and other parameters controlled for 20 hours, and intensive therapy to 72 hours. CPB achieved ROSC more successfully (ten of ten vs six of ten controls) (P less than .05), and more rapidly, with fewer defibrillation attempts and with less epinephrine (P less than .05). CPB improved 72-hour survival (seven of ten vs two of ten controls) (P = .025). Between two and 24 hours, of those with ROSC, intractable cardiogenic shock killed four of six control dogs (NS). CPB was followed by fewer arrhythmias. CPB increased recovery of consciousness (five of ten CPB vs zero of six controls with ROSC) (P = .037), but achieved neurologic normality in only one of ten. Cardiac arrest and CPB (without CPR) resulted in less myocardial morphologic damage than did standard CPR (P less than .025).(ABSTRACT TRUNCATED AT 250 WORDS)