Vasopressin improves vital organ blood flow after prolonged cardiac arrest with postcountershock pulseless electrical activity in pigs

Objective: Although a benefit of vasopressin when compared with epinephrine was shown during cardiopulmonary resuscitation (CPR) after a short duration of ventricular fibrillation cardiac arrest, the effect of vasopressin during prolonged cardiac arrest with pulseless electrical activity is currently unknown. Design: Prospective, randomized laboratory investigation using an established porcine model with instrumentation for measurement of hemodynamic variables, vital organ blood flow, blood gases, and return of spontaneous circulation. Setting: University hospital laboratory. Subjects: Eighteen domestic pigs. Interventions: After 15 mins of cardiac arrest and 3 mins of chest compressions, 18 animals were randomly treated with either 0.8 units/kg vasopressin (n = 9) or 200 μg/kg epinephrine (n = 9). Measurements and Main Results: Compared with epinephrine, vasopressin resulted, at both 90 secs and 5 mins after drug administration, in significantly higher (p < .05) median (25th-75th percentiles) left ventricular myocardial blood flow (120 [range, 96193] vs. 54 [range, 11-92] and 56 [range, 41-80] vs. 21 [range, 1140] mL/min/100 g, respectively) and total cerebral blood flow (85 [78-102] vs. 24 [18-41] and 50 [44-52] vs. 8 [5-23] mL/min/100 g, respectively). Spontaneous circulation was restored in eight of nine animals in the vasopressin group and in one of nine animals in the epinephrine group (p= .003). Conclusions: Compared with a maximum dose of epinephrine, vasopressin significantly increased left ventricular myocardial and total cerebral blood flow during CPR and return of spontaneous circulation in a porcine model of prolonged cardiac arrest with postcountershock pulseless electrical activity.