Uncertainties about the use of inhaled nitric oxide in preterm infants

Respiratory failure in the premature neonate is frequently complicated by p ulmonary hypertension. When conventional therapies including administration of exogenous surfactant, conventional mechanical ventilation or high-frequ ency oscillatory ventilation using an appropriate high-volume strategy have failed. one should assess the pulmonary circulation status with colour-cod ed Doppler echocardiography. There is now considerable evidence that the re gulation of foetal and postnatal pulmonary circulation occurs via nitric ox ide (NO), and that persistent pulmonary hypertension of the neonate may be related to a relative deficiency in NO release. Low-dose (10-20 ppm), short -duration (1-2 d) inhaled NO has generally been shown to improve the oxygen ation and relieve pulmonary hypertension in premature neonates with severel y hypoxaemic respiratory failure. Whether this therapy (eventually prolonge d >1-3 wk?) would improve survival and lessen morbidity (e.g. intracranial haemorrhage and chronic lung disease) remains to be proven by appropriately designed controlled trials. Until these issues can be clarified, NO therap y for premature neonates should be still considered as an experimental drug , and its use restricted to clinical studies.