Cardiopulmonary bypass vs CPR as treatment for prolonged canine cardiopulmonary arrest

Although in vitro studies have demonstrated functional recovery of neurons after prolonged ischemia, in vivo experience with patients resuscitated from cardiopulmonary arrest demonstrates much less cerebral resistance to global ischemia. The purpose of our investigation was to compare the effectiveness of femoro-femoral veno-arterial cardiopulmonary bypass (CPB) to standard cardiopulmonary resuscitation in the treatment of prolonged cardiopulmonary arrest. Ten mongrel dogs were electrically fibrillated and left in cardiopulmonary arrest without any therapy for 12 minutes. Subsequently, either CPB (n = 5) or CPR (n = 5) was initiated and resuscitation attempted according to a standardized protocol that included administration of the calcium channel blocker lidoflazine in an effort to optimize cerebral and myocardial recovery. If there was return of spontaneous circulation, the animal was managed in an intensive care setting with invasive hemodynamic monitoring and ventilatory support for up to nine hours. Neurologic function was graded using a standardized neurologic deficit scoring (NDS) system at 12 hours after insult and daily for one week or until death. Prearrest hemodynamic and metabolic parameters were comparable in both groups (P greater than .05). All CPB animals were resuscitated successfully and alive at 24 hours after insult as opposed to none in the CPR group (P less than .005). In addition, three of the CPB animals were neurologically normal at final grading with NDS scores of zero. The other two CPB animals had persistent severe neurologic impairment and a mean NDS score of 51%. Thus CPB is more effective than CPR in the treatment of prolonged cardiopulmonary arrest. The improved outcome probably results primarily from improvement in blood flow with CPB.(ABSTRACT TRUNCATED AT 250 WORDS)