Vasopressin Improves Vital Organ Blood Flow During Closed-Chest Cardiopulmonary Resuscitation in Pigs

Abstract

This study was designed to compare the effects of epinephrine with those of vasopressin on vital organ blood flow during closed-chest cardiopulmonary resuscitation (CPR) in a pig model of ventricular fibrillation. Vasopressin was compared with epinephrine by randomly allocating 28 pigs to receive either 0.2 mg/kg epinephrine (n = 7), 0.2 U/kg vasopressin (low dose) (n = 7), 0.4 U/kg vasopressin (medium dose) (n = 7), or 0.8 U/kg vasopressin (high dose) (n = 7) after 4 minutes of ventricular fibrillation and 3 minutes of closed-chest CPR. Left ventricular myocardial blood flow, determined by use of radiolabeled microspheres during CPR, before and then 90 seconds and 5 minutes after drug administration was 17 +/- 2, 43 +/- 5, and 22 +/- 3 mL.min-1.100 g-1 (mean +/- SEM) in the epinephrine group; 18 +/- 2, 50 +/- 6, and 29 +/- 3 mL.min-1.100 g-1 in the low-dose vasopressin group; 17 +/- 3, 52 +/- 8, and 52 +/- 6 mL.min-1.100 g-1 in the medium-dose vasopressin group; and 18 +/- 2, 95 +/- 9, and 57 +/- 6 mL.min-1.100 g-1 in the high-dose vasopressin group (P < .001 at 90 seconds and 5 minutes between epinephrine and high-dose vasopressin, and P < .01 at 5 minutes between epinephrine and medium-dose vasopressin). At the same times, calculated coronary systolic perfusion pressures were 12 +/- 2, 36 +/- 5, and 18 +/- 2 mm Hg in the epinephrine group; 10 +/- 1, 39 +/- 6, and 26 +/- 5 mm Hg in the low-dose vasopressin group; 11 +/- 2, 49 +/- 6, and 38 +/- 5 mm Hg in the medium-dose vasopressin group; and 10 +/- 2, 70 +/- 5, and 47 +/- 6 mm Hg in the high-dose vasopressin group (P < .01 at 90 seconds and 5 minutes between epinephrine and high-dose vasopressin); and calculated coronary diastolic perfusion pressures were 15 +/- 2, 24 +/- 2, and 19 +/- 2 mm Hg in the epinephrine group; 13 +/- 1, 25 +/- 2, and 20 +/- 1 mm Hg in the low-dose vasopressin group; 13 +/- 2, 25 +/- 2, and 21 +/- 2 mm Hg in the medium-dose vasopressin group; and 13 +/- 2, 35 +/- 3, and 24 +/- 2 mm Hg in the high-dose vasopressin group (P < .05 at 90 seconds between epinephrine and high-dose vasopressin). Total cerebral blood flow was significantly higher after high-dose vasopressin than after epinephrine (P < .05 at 90 seconds and P < .01 at 5 minutes between groups). Five animals in the epinephrine, 5 in the low-dose vasopressin, 7 in the medium-dose vasopressin, and 6 in the high-dose vasopressin groups were successfully resuscitated and survived the 1-hour observation period. We conclude that administration of vasopressin leads to a significantly higher coronary perfusion pressure and myocardial blood flow than epinephrine during closed-chest CPR in a pig model of ventricular fibrillation.