Factors influencing variable outcomes after ventricular fibrillation cardiac arrest of 15 minutes in dogs

Animal experiments with cardiac arrest and cardiopulmonary resuscitation (CPR) despite controlled insult and postinsult life support, have yielded variable individual outcomes. This report concerns 10 dog experiments with a standardized model of VF cardiac arrest with no flow for 10 min followed by CPR basic life support (BLS) from VF 10 to 15 min and then CPR advanced life support (ALS) with epinephrine at 15 min. Defibrillating countershocks began at 17 min, for restoration of spontaneous circulation. After controlled ventilation to 20 h and intensive care to 96 h, outcome was evaluated using the overall performance category (OPC) 1 (normal) (n5) vs. OPC 2-4 (impaired) (n5) (P less than 0.001). We searched for correlations between normal vs. impaired outcome in various prearrest, arrest and postarrest factors that are suspected to influence postarrest neurologic deficit. Prearrest variables were similar in the normal and impaired groups. Resuscitation variables were similar in both. Coronary perfusion pressure during CPR-ALS was higher in the normal outcome group (P = 0.03). Among postarrest variables, postarrest reperfusion pressure pattern (initial hypertensive bout), blood glucose, cardiac output, Hct, pHa, PaO2 and PaCO2 were the same. Our data support the importance of maximizing coronary perfusion pressure not only for restoration of heart beat but also as a possible predictor of improved cerebral outcome.