Cardiopulmonary bypass after cardiac arrest and prolonged closed-chest CPR in dogs

Abstract

We studied a clinically realistic field-to-hospital scenario in dogs with four-minute ventricular fibrillation (VF) cardiac arrest followed by 30-minute standard external CPR basic life support (BLS). At the end of this 34-minute insult, cardiopulmonary bypass (CPB) was used for early defibrillation and assisted circulation for one hour (n = 10). Recovery was compared with that of control dogs (n = 10) in which standard CPR with advanced life support (ALS) for another 30 minutes was used for restoration of spontaneous circulation (ROSC). Both groups had hemodilution and heparinization; controlled blood pressure, blood gases, ventilation, and other parameters for 20 hours; and intensive care to 72 hours. During CPR-BLS of 30 minutes in both groups signs of cerebral viability returned. CPB achieved ROSC more successfully (ten of ten vs five of ten CPR-ALS controls) (P less than .02); and more rapidly, with less defibrillation energy (first countershock in eight of ten) and with less epinephrine (P less than .01). CPB improved 72-hour survival (seven of ten vs three of ten controls) (P less than .05). Between two and 24 hours, of those with ROSC, cardiac complications killed three of ten CPB dogs (after weaning), and two of five CPR-ALS dogs (NS). All seven CPB survivors to 72 hours were neurologically normal; of the three CPR-ALS survivors, one remained with severe neurologic deficit and two were neurologically normal (seven of ten CPB vs two of ten controls, P = .025). Starting CPR-BLS within four minutes of arrest can maintain cerebral viability.(ABSTRACT TRUNCATED AT 250 WORDS)