Amrinone versus dopamine and nitroglycerin in neonates after arterial switch operation for transposition of the great arteries

Abstract

Objective: To compare the efficacy and safety of amrinone and a combination of dopamine and nitroglycerin in neonates after reconstructive surgery for transposition of the great arteries. Design: A prospective, randomized, double-blind study. Setting: Pediatric intensive care unit in a university hospital. Participants: Thirty-five neonates with transposition of the great arteries. Interventions: A loading dose of amrinone, 2 mg/kg, followed by a maintenance infusion of 7.5 μg/kg/min, were administered to 16 neonates before separation from cardiopulmonary bypass. The remaining 19 patients were administered a combination of dopamine, 5 μg/kg/min, and nitroglycerin, 1 μg/kg/min. An open-label epinephrine infusion was administered in both groups as required. Measurements and Main Results: The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (1.7 ± 0.5 L/min/m 2 (mean ± SD]) compared with the dopamine-nitroglycerin group (1.4 ± 0.4 L/min/m 2; p < 0.04). The systemic vascular resistance in the amrinone group was lower (26 ± 8 Wood units × m 2) than in the dopamine-nitroglycerin group (35 ± 12 Wood units × m 2; p < 0.02). The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.34 ± 0.08) compared with the amrinone group (0.28 ± 0.06; p < 0.02). Lower platelet counts were observed in the amrinone group, but no difference in hemorrhagic complications was seen between the groups. Conclusion: With the dosage regimen used, supplemented with epinephrine, amrinone provides a higher cardiac output and more favorable oxygen dynamics than a combination of dopamine and nitroglycerin.