Inhaled nitric oxide and prevention of pulmonary hypertension after congenital heart surgery: a randomised double-blind study

Background Pulmonary hypertensive crises (PHTC) are a major cause of morbid ity and mortality after congenital heart surgery. inhaled nitric oxide is f requently used as rescue therapy. We did a randomised double-blind study to investigate the role of routinely administered inhaled nitric oxide to pre vent pulmonary hypertension in infants at high risk. Methods We enrolled 124 infants (64 male, 60 female; median age 3 months [I QR 1-5]), 76% with large ventricular or atrioventricular septal defects, wh o had high pulmonary flow, pressure, or both. and were undergoing correctiv e surgery for congenital heart disease. They were randomly assigned continu ous low-dose inhaled nitric oxide (n=63) or placebo (n=61) from surgery unt il just before extubation. We measured the numbers of PHTC, time on study g as, and hours spent in intensive care. Analysis was done by intention to tr eat. Findings Compared with placebo, infants receiving inhaled nitric oxide had fewer PHTC (median four [IQR 0-12] vs seven [1-19]; relative risk, unadjust ed 0.66, p<0.001, adjusted for dispersion 0.65, p=0.045) and shorter times until criteria for extubation were met (80 [38-121] vs 112 h [63-164], p=0. 019). Time taken to wean infants off study gas was 35% longer in the nitric oxide group than in the placebo group (p=0.19), but the total time on the study gas was still 30 h shorter for the nitric oxide group (87 [43-125] vs 117 h [67-168], p=0.023). No important toxic effects arose. Interpretation In infants at high risk of pulmonary hypertension, routine u se of inhaled nitric oxide after congenital heart surgery can lessen the ri sk of pulmonary hypertensive crises and shorten the postoperative course, w ith no toxic effects.