INHALED NITRIC-OXIDE FOR CHILDREN WITH CONGENITAL HEART-DISEASE AND PULMONARY-HYPERTENSION

Background. Endothelium-derived nitric oxide (NO) is a potent vasodila tor and a major mediator of pulmonary vascular tone. Methods. Five inf ants underwent a trial of inhaled NO with hemodynamic monitoring in th e operating room after atrioventricular canal repair. An additional 15 patients with congenital heart disease and refractory pulmonary hyper tension were treated with inhaled NO for 1 day to 10 days postoperativ ely. Results. In the 5 infants with atrioventricular canal, corrective surgical intervention and conventional therapy (hyperventilation, ins pired oxygen fraction of 0.80, and inotropic agents) lowered mean pulm onary artery pressure from 49.5 +/- 10.5 to 20.0 +/- 2.2 mm Hg (p < 0. 001). Adding inhaled NO further decreased mean pulmonary artery pressu re to 18.0 +/- 2.8 mm Hg (p = not significant). Inhaled NO had no effe ct on ventricular function curves (inflow occlusion) in this group. In the 15 patients with refractory postoperative pulmonary hypertension, 11 had a favorable response to inhaled NO, with a decrease in mean pu lmonary artery pressure from 30.9 +/- 5.8 to 23.1 +/- 5.4 mm Hg (p < 0 .01) in 8 patients with pulmonary artery catheters. Conclusions. These studies demonstrate that inhaled NO has minimal beneficial effect on pulmonary artery pressure or cardiac output in infants after repair of atrioventricular canal. Inhaled NO is effective in decreasing PAP pos toperatively in select patients with congenital heart disease and pulm onary hypertension refractory to conventional therapeutic modalities.