Objective: To assess the school-age medical and functional outcomes of inhaled nitric oxide (iNO)-treated premature infants.

Methods: The study cohort consisted of survivors from a randomised trial of iNO for 7 days or placebo in premature infants with respiratory distress syndrome requiring mechanical ventilation and surfactant replacement. Medical and functional outcomes, including somatic growth, hospitalisations and ongoing morbidities, were obtained from physical examination and questionnaire. A poor medical outcome was defined as multiple chronic morbidities or technology dependence. A suboptimal functional outcome was a total WeeFIM of <80 among children in school and not requiring intensive rehabilitation. Statistical comparisons were made using Wilcoxon rank sum or Fisher’s exact tests.

Results: 135 of 167 survivors (81%) were studied at 5.7 ± 1.0 years (65 placebo-treated and 70 iNO treated). No differences in anthropometric measures were detected: weight z-score (placebo −0.45 vs iNO −0.12; p = 0.11), head circumference z-score (placebo −0.93 vs iNO −0.85; p = 0.20), height z-score (placebo −0.06 vs iNO 0.23; p = 0.42). There was no difference in hospitalisations (p = 0.94). However, iNO-treated children were less likely to have poor medical outcomes (placebo n = 9, 14% versus iNO n = 2, 3%; p = 0.03). In addition, iNO-treated children were less likely to have functional limitations that interfered with educational and community activities (placebo 5/58, 9% vs iNO 0/60, 0%; p = 0.03). There was no difference in the frequency of severe neurodevelopmental disability (severe cerebral palsy, blindness, deafness, IQ <70).

Conclusions: These results demonstrate the long-term safety of iNO in premature infants. In addition, iNO treatment may decrease poor medical and suboptimal functional outcomes in this at-risk population.