Milrinone and nitric oxide: combined effect on pulmonary artery pressures after cardiopulmonary bypass in children

Abstract

Objective: To investigate the effect of milrinone combined with nitric oxide (NO) on the pulmonary artery pressures (PAP) after cardiopulmonary bypass (CPB), for repair of congenital heart defects (CHD) in children.

Design: Prospective, randomized, double-blind study.

Setting: University affiliated community hospital.

Participants: Ninety children with pulmonary hypertension and repair of CHD.

Interventions: After weaning from CPB, patients (30 in each group) received 3 drug regimens: group 1, nitric oxide (NO); group 2, a continuous infusion of milrinone; and group 3, a combination of the 2. Drugs were started after CPB and given for 20 minutes.

Measurements and main results: Pulmonary and systemic pressures, PaCO(2), SaO(2), and pH values were recorded before bypass, after weaning from CPB, 10 and 20 minutes after starting each regimen, and 10 minutes after the cessation of treatment. Mean systemic blood pressure was lower (p < 0.05) in the combined treatment group after discontinuation of the drugs. Although mean PAP values were lower in the combined group (p < 0.05), no difference was recorded with regard to pH, PaCO(2), and PaO(2). The ratio between pre- and post-treatment mean PAP was highest in group 3(1.26 +/- 0.5) and lowest in group 2 (0.99 +/- 0.3, p < 0.001). The mean PAP recorded after discontinuation of the drug was lower than the baseline value in groups 1 and 3 (p < 0.05).

Conclusions: The combination of milrinone and NO produced a more pronounced decrease in PAP than milrinone alone.