INHALED NITRIC-OXIDE AND PERSISTENT PULMONARY-HYPERTENSION OF THE NEWBORN

Background Persistent pulmonary hypertension of the newborn causes sys temic arterial hypoxemia because of increased pulmonary vascular resis tance and right-to-left shunting of deoxygenated blood. Inhaled nitric oxide decreases pulmonary vascular resistance in newborns. We studied whether inhaled nitric oxide decreases severe hypoxemia in infants wi th persistent pulmonary hypertension. Methods In a prospective, multic enter study, 58 full-term infants with severe hypoxemia and persistent pulmonary hypertension were randomly assigned to breathe either a con trol gas (nitrogen) or nitric oxide (80 parts per million), mixed with oxygen from a ventilator. If oxygenation increased after 20 minutes a nd systemic blood pressure did not decrease, the treatment was conside red successful and was continued at lower concentrations. Otherwise, i t was discontinued and alternative therapies, including extracorporeal membrane oxygenation, were used. Results Inhaled nitric oxide success fully doubled systemic oxygenation in 16 of 30 infants (53 percent), w hereas conventional therapy without inhaled nitric oxide increased oxy genation in only 2 of 28 infants (7 percent). Long-term therapy with i nhaled nitric ox ide sustained systemic oxygenation in 75 percent of t he infants who had initial improvement. Extracorporeal membrane oxygen ation was required in 71 per cent of the control group and 40 percent of the nitric oxide group (P=0.02). The number of deaths was similar i n the two groups. Inhaled nitric oxide did not cause systemic hypotens ion or increase methemoglobin levels. Conclusions Inhaled nitric oxide improves systemic oxygenation in infants with persistent pulmonary hy pertension and may reduce the need for more invasive treatments. (C) 1 997, Massachusetts Medical Society.