Comparison of the hemodynamic effects of milrinone with dobutamine in patients after cardiac surgery

Abstract

Objective: To compare the hemodynamic effects, efficacy, and safety of intravenous milrinone (M), 50 microg/kg during 10 minutes followed by 0.5 microg/kg/min, with intravenous dobutamine (D), 10 to 20 microg/kg/min, in patients with low cardiac output after cardiac surgery.

Design: Randomized, open-label, multicenter study.

Setting: Cardiothoracic surgery departments, operating rooms, and intensive care units in 6 university hospitals.

Participants: Patients (n = 120; 60 per group) after elective cardiac surgery.

Interventions: None.

Measurements and main results: Analysis compared the hemodynamics at baseline and the percentage change from baseline during 4 hours of the drug infusion. The incidence of adverse events was recorded. Both groups had low mean (+/- SEM) cardiac indices (M, 1.6 ([0.03] L/min/m(2); D, 1.7 [0.03] L/min/m(2)) in association with adequate mean pulmonary capillary wedge pressures (M, 13.7 [1.3] mmHg; D, 12.7 [1.9] mmHg) at baseline. Group M had significantly higher systemic arterial pressures and systemic vascular resistances compared with group D; otherwise, the hemodynamics in both groups were comparable. During the study, hemodynamic responses included the following: group D had greater increases in cardiac index (at 1 hour, D = 55%, M = 36%; p < 0.01), heart rate (at 1 hour, D = 35%, M = 10%; p < 0.001), arterial pressures (mean arterial pressure at 1 hour, D = 31%, M = 7%; p < 0.001), and left ventricular stroke work index (at 1 hour, D = 75%, M = 45%; p < 0.05). Group M had greater decreases in mean pulmonary capillary wedge pressure (at 1 hour, D = -3%, M = -14%; p < 0.05). Comparisons of adverse events showed that dobutamine was associated with a higher incidence of hypertension (D = 40%, M = 13%; p < 0.02) and change of rhythm from sinus to atrial fibrillation (D = 18%, M = 5%; p < 0.04). Milrinone was associated with a higher incidence of sinus bradycardia (D = 2%, M = 13%; p < 0.03).

Conclusions: Milrinone and dobutamine are appropriate and comparable for the pharmacologic treatment of the low- output syndrome after cardiopulmonary bypass.