Comparison of epinephrine and vasopressin in a pediatric porcine model of asphyxial cardiac arrest

Objective This study was designed to compare the effects of vasopressin vs. epinephrine vs. the combination of epinephrine with vasopressin on vital organ blood flow and return of spontaneous circulation in a pediatric porcine model of asphyxial arrest. Design Prospective, randomized laboratory investigation using an established porcine model for measurement of hemodynamic variables, organ blood flow, blood gases, and return of spontaneous circulation. Setting University hospital laboratory. Subjects Eighteen piglets weighing 8-11 kg. Interventions Asphyxial cardiac arrest was induced by clamping the endotracheal tube. After 8 mins of cardiac arrest and 8 mins of cardiopulmonary resuscitation, a bolus dose of either 0.8 units/kg vasopressin (n = 6), 200 microg/kg epinephrine (n = 6), or a combination of 45 microg/kg epinephrine with 0.8 units/kg vasopressin (n = 6) was administered in a randomized manner. Defibrillation was attempted 6 mins after drug administration. Measurements and main results Mean +/- SEM coronary perfusion pressure, before and 2 mins after drug administration, was 13 +/- 2 and 23 +/- 6 mm Hg in the vasopressin group; 14 +/- 2 and 31 +/- 4 mm Hg in the epinephrine group; and 13 +/- 1 and 33 +/- 6 mm Hg in the epinephrine-vasopressin group, respectively (p = NS). At the same time points, mean +/- SEM left ventricular myocardial blood flow was 44 +/- 31 and 44 +/- 25 mL x min-(1) x 100 g(-1) in the vasopressin group; 30 +/- 18 and 233 +/- 61 mL x min(-1) x 100 g(-1) in the epinephrine group; and 36 +/- 10 and 142 +/- 57 mL x min(-1) x 100 g(-1) in the epinephrine-vasopressin group (p < .01 epinephrine vs. vasopressin; p < .02 epinephrine-vasopressin vs. vasopressin). Total cerebral blood flow trended toward higher values after epinephrine-vasopressin (60 +/- 19 mL x min(-1) x 100 g(-1)) than after vasopressin (36 +/- 17 mL x min(-1) x 100 g(-1)) or epinephrine alone (31 +/- 7 mL x min(-1) x 100 g(-1); p = .07, respectively). One of six vasopressin, six of six epinephrine, and four of six epinephrine-vasopressin-treated animals had return of spontaneous circulation (p < .01, vasopressin vs. epinephrine). Conclusions Administration of epinephrine, either alone or in combination with vasopressin, significantly improved left ventricular myocardial blood flow during cardiopulmonary resuscitation. Return of spontaneous circulation was significantly more likely in epinephrine-treated pigs than in animals resuscitated with vasopressin alone.