Repair of ventricular septal defect in a child with severe pulmonary hypertension--response to inhaled nitric oxide.

Nitric oxide (NO), was administered successfully, to a child with severe pulmonary hypertension, following surgical repair of a large ventricular septal defect. Inhalation of NO, 20-25 parts per million (ppm) was continued for 24 h, resulting in mean pulmonary artery pressure (PAP) of 25 mmHg and permitting a reduction in both ventilatory and inotropic support. Weaning of NO was commenced. At 5 ppm, administration was discontinued. An immediate and dramatic increase in PAP occurred. A similar pattern resulted on further attempts, demonstrating the extreme sensitivity of the pulmonary vasculature to the effects of inhaled low dose NO and the selectivity of the response.