Milrinone improves oxygenation in neonates with severe persistent pulmonary hypertension of the newborn

Abstract

Background: Many neonates with severe persistent pulmonary hypertension of the newborn (PPHN) are nonresponders to inhaled nitric oxide (iNO). Milrinone is a promising adjunctive therapy because of its pulmonary vasodilator properties and cardiotropic effects. Design: Case series of neonates with severe PPHN (defined as oxygenation index [OI] >20, failure of iNO therapy, and echocardiographic confirmation of PPHN). Setting: Tertiary neonatal intensive care unit. Subjects: Full-term (≥37 weeks) neonates with severe PPHN who received intravenous milrinone. Measurements: The primary end point was the effect of intravenous milrinone on OI and hemodynamic stability over a 72-hour study period. Secondary end points examined included duration of iNO and degree of cardiorespiratory support. Results: Nine neonates at a mean gestation of 39.25 ± 2.76 weeks, birth weight of 3668 ± 649.1 g, and baseline OI of 28.1 ± 5.9 received milrinone treatment after a poor initial response to iNO treatment. Intravenous milrinone was commenced at a median age of 21 hours (range, 18-49 hours), and patients were treated for median of 70 hours (range, 23-136). Oxygenation index was significantly reduced after milrinone treatment, particularly in the immediate 24 hours of treatment (8.0 ± 6.6, P < .001). There was a significant improvement in heart rate (179 ± 15.2 vs 149.6 ± 22.4, P < .001) over the same period. Infants who received milrinone did not develop systemic hypotension; in fact, there was a nonsignificant trend toward improved blood pressure. Conclusions: Intravenous milrinone produces early improvements in oxygenation without compromising systemic blood pressure. © 2006 Elsevier Inc. All rights reserved.