Randomized Trial of Milrinone Versus Placebo for Prevention of Low Systemic Blood Flow in Very Preterm Infants

Abstract

To assess the effectiveness of early prophylactic milrinone versus placebo for prevention of low systemic blood flow in high-risk preterm infants. Double-blind randomized placebo controlled trial of milrinone (loading dose 0.75 microg/kg/min for 3 hours then maintenance 0.2 microg/kg/min until 18 hours after birth) versus placebo. Infants born <30 weeks gestational age and <6 hours of age were eligible and were monitored with serial echocardiography, head ultrasound scanning, and continuous invasive blood pressure. Primary outcome was maintenance of superior vena cava (SVC) flow > or =45 mL/kg/min through the first 24 hours. The exit criterion was hypotension unresponsive to volume and inotropes. Ninety infants were enrolled, equal proportions maintained SVC flow > or =45 mL/kg/min after treatment commenced. No significant difference was observed in SVC flow, right ventricular output, and blood pressure during the first 24 hours; or grades 3 to 4 periventricular/intraventricular hemorrhage and death. Heart rate was higher and constriction of the ductus was slower in the infants randomized to milrinone. Milrinone did not prevent low systemic blood flow during the first 24 hours in very preterm infants, and no adverse effects were attributable to milrinone. Use of a preventative treatment with rescue model allowed comparison of an inotrope with placebo in this high-risk group of infants.