Cardiopulmonary arrest and resuscitation produces tremendous physiological stress with resultant biochemical derangements. We undertook this study to determine insulin and glucose levels during cardiopulmonary arrest in the canine model. Baseline insulin and glucose levels were obtained from an ascending aortic arch catheter in six mongrel dogs. Ventricular fibrillation was induced by an electrical stimulus and ventilation was terminated. After five minutes of fibrillation, cardiopulmonary resuscitation (CPR) was initiated using external, mechanical CPR and a continuous epinephrine infusion at 5 micrograms/kg/min. Serum insulin and glucose levels were repeated 15 minutes after beginning CPR. Mean blood glucose 15 minutes after initiation of resuscitation (379 +/- 114 mg/dL) was significantly increased from prearrest levels (124 +/- 29 mg/dL, P less than .01). Mean serum insulin 15 minutes after initiation of resuscitation (11.3 +/- 3.3 microU/mL) was significantly decreased compared to prearrest levels (16.2 +/- 6.0 microU/mL, P less than .05). During ischemia, the myocardium becomes dependent primarily on glucose as a source of energy. Inappropriately low insulin levels during CPR may adversely affect an already compromised myocardial glucose metabolism. Further investigation is needed to determine the utility of insulin infusion during CPR.