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 porci ne model of asphyxial arrest. Design: Prospective, randomized laboratory investigation using an establish ed 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 endotra cheal tube. After 8 mins of cardiac arrest and 8 mins of cardiopulmonary re suscitation, a bolus dose of either 0.8 units/kg vasopressin (n = 6), 200 m ug/kg epinephrine (n = 6), or a combination of 45 mug/kg epinephrine with 0 .8 units/kg vasopressin (n = 6) was administered in a randomized manner. De fibrillation was attempted 6 mins after drug administration. Measurements and Main Results: Mean +/- SEM coronary perfusion pressure, be fore 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 gr oup; and 13 +/- 1 and 33 +/- 6 mm Hg in the epinephrine-vasopressin group, respectively (p = NS). At the same time points, mean +/- SEM left ventricul ar myocardial blood flow was 44 +/- 31 and 44 +/- 25 mL . min(-1) . 100 g(- 1) in the vasopressin group; 30 +/- 18 and 233 +/- 61 mL min-1 100 g(-1) in the epinephrine group; and 36 +/- 10 and 142 +/- 57 mL . min(-1) . 100 g(- 1) in the epinephrine-vasopressin group (p < .01 epinephrine vs. vasopressi n; p < .02 epinephrine-vasopressin vs. vasopressin). Total cerebral blood f low trended toward higher values after epinephrine-vasopressin (60 +/- 19 m L . min(-1) . 100 g(-1)) than after vasopressin (36 +/- 17 mL . min(-1) . 1 00 . g(-1)) or epinephrine alone (31 +/- 7 mL . min(-1) 100 . g(-1); p = .0 7, respectively). One of six vasopressin, six of six epinephrine, and four of six epinephrine-vasopressin-treated animals had return of spontaneous ci rculation (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 circulatio n was significantly more likely in epinephrine-treated pigs than in animals resuscitated with vasopressin alone.