Efficacy of inhaled iloprost in the management of pulmonary hypertension after cardiopulmonary bypass in infants undergoing congenital heart surgery. A case series of 31 patients

INTRODUCTION: Reactive pulmonary hypertension is frequent in children with high pulmonary flow and pressure. Inhaled iloprost and nitric oxide are the only substances approved as selective pulmonary vasodilators, but data about the effectiveness and safety of inhaled iloprost during cardiac surgery in infants and children are limited. METHODS: We retrospectively analysed the effects of inhaled iloprost after cardiopulmonary bypass weaning on the ratio of mean pulmonary artery to mean arterial pressure. The effectiveness of the inhalation set up was tested in an in vitro study. RESULTS: Thirty-one patients received inhaled iloprost during surgery. The clinically used inhalation set up for inhaled iloprost delivered 20% to 30% (500 to 750 ng * kg-1) of the nebulizer dose and caused a decrease in the ratio of mean pulmonary artery to mean arterial pressure from 0.6±0.2 to 0.4±0.1 and 0.4±0.1 (30 and 60 minutes after)p <0.05. In eleven (35%) patients norepinephrine infusion was started. CONCLUSION: Our data suggest that a single dose of inhaled iloprost significantly decreases the ratio of mean pulmonary artery to mean arterial pressure for at least 60 min. Vasopressor support may be indicated to avoid systemic hypotension. The filled dose in the nebulizer should be high enough to compensate for the high depletion rate of the pediatric inhalation system. However, our study allows no final decision about beneficial or detrimental effects of the off label use of inhaled iloprost to reduce pulmonary artery pressure during congenital heart surgery.