Intrapulmonary epinephrine during prolonged cardiopulmonary resuscitation: improved regional blood flow and resuscitation in dogs.

Blood flow to vital organs was measured at five-minute intervals during 20 minutes of cardiopulmonary resuscitation (CPR) and ventricular fibrillation in two groups of anesthetized dogs (n = 15 per group). The relationship between organ blood flow and restoration of circulation after 20 minutes was assessed with no additional treatment in Group I and with intrapulmonary epinephrine in Group II. Cardiac output and organ blood flow did not vary significantly in Group I. In Group II, intrapulmonary epinephrine significantly improved blood flow to the myocardium, the brain, and the adrenals. A mean myocardial blood flow of less than 0.13 mL/min/g resulted in no survival, while a flow of greater than 0.16 mL/min/g resulted in survival. These studies show that a critical level of myocardial blood flow is required to restore ability of the heart to function as a pump after prolonged CPR, and that a drug that increases flow improves resuscitation efforts.