Inhaled nitric oxide in persistent pulmonary hypertension of the newborn refractory to high-frequency ventilation

The birth weight and the gestational age of infants were 3125.5 ± 794 g (mean ± SD) and 39 ± 2.4 weeks, respectively. All neonates were ventilated for an average of 137.5 min (range 90-180 min) prior to NO therapy. The mean oxygenation index (OI) of all neonates prior to NO was 46.3 ± 5 (mean ± SEM). NO was initially administered at 20 parts per million (ppm) for at least 2 h and increased gradually by 2 ppm to a maximum of 80 ppm.Eighteen infants (75%) responded and six (25%) did not respond to the treatment. Three neonates died in the responding group, while all the non-responders died (P = 0.0001). The survival rate was 62.5% among all neonates. NO significantly decreased OI (P < 0.0001) and improved the arterial/alveolar (a/A) oxygen ratio (P < 0.0001) within the first 2 h of NO therapy in 61.1% of the responders. However, the OI and the a/A oxygen ratio remained almost the same throughout the treatment in the non-responders and the non-survivors.Inhaled NO at 20 ppm, following adequate ventilation for 2 h without significant response, could be used to identify the majority of the non-responders in order to seek other alternatives.A wide range of life-threatening lung diseases are characterized by compromised capacity of the lung to match ventilation and perfusion. This results in poor oxygenation of arterial blood and significant hypoxemia. Pulmonary hypertension and poor myocardial function often play a role in the pathophysiology of pulmonary disease [1]. Several vasodilator agents have been shown to decrease pulmonary vascular resistance, but their use was limited by concomitant decreases in systemic vascular resistance and worsening of intrapulmonary shunt [2]. Recently, selective pulmonary vasodilation with inhalational nitric oxide (INO) has been demonstrated in both clinical and experimental settings [3,4,5].This pilot study was conducted to evaluate the effect of INO in the management of neonates with severe persistent pulmonary hypertension refractory