The use of inhaled nitric oxide in newborn medicine.

Persistent pulmonary hypertension is common in neonates with respiratory failure. It is characterized by pulmonary hypertension and extrapulmonary right-to-left shunting across the foramen ovale and ductus arteriosus. Nitric oxide has been found to be an important inter- and intracellular messenger in virtually every organ in the body. Inhaled nitric oxide (iNO) is a selective pulmonary vasodilator. The use of iNO improves oxygenation in severely hypoxemic neonates, showing both acute and sustained improvement. It decreases pulmonary arterial pressure, and improves ventilation-perfusion mismatch. This, in turn, may lessen the need for extracorporeal membrane oxygenation. This article reviews the discovery of nitric oxide, its metabolism, its use in persistent pulmonary hypertension of the newborn (PPHN), long-term follow-up, and safety issues related to NO. It has recently been approved by the FDA for the treatment of hypoxic respiratory failure associated with PPHN.