THE EFFECTS OF INHALED NITRIC-OXIDE ON POSTOPERATIVE PULMONARY-HYPERTENSION IN INFANTS AND CHILDREN UNDERGOING SURGICAL REPAIR OF CONGENITAL HEART-DISEASE

The role of inhaled nitric oxide in the immediate postbypass period af ter surgical repair of congenital heart disease is uncertain. In a con trolled, randomized, double-blind study, we tested the hypothesis that inhaled nitric oxide (NO) would reduce pulmonary hypertension immedia tely after surgical repair of congenital heart disease in 40 patients with preoperative evidence of pulmonary hypertension (mean pulmonary a rterial pressure [MPAP] exceeding 50% of mean systemic arterial pressu re [MSAP]). Patients were then followed in the intensive care unit (IC U) to document the incidence of severe pulmonary hypertension Of the p atients, 36% (n = 13) emerged from bypass with MPAP >50% MSAP. In thes e patients, inhaled NO reduced MPAP by 19% (P = 0.008) versus an incre ase of 9% in the placebo group. No effect on MPAP was observed in pati ents emerging from bypass without pulmonary hypertension (n = 23). Inh aled NO was required five times in the ICU, always in the patients who had emerged from cardiopulmonary bypass with pulmonary hypertension ( 5 of 13 [38%] versus 0 of 23). We conclude that, in infants and childr en undergoing congenital heart surgery, inhaled NO selectively reduces MPAP in patients who emerge from cardiopulmonary bypass with pulmonar y hypertension and has no effect on those who emerge without it. Impli cations: In a randomized double-blind study, inhaled nitric oxide sele ctively reduced pulmonary artery pressures in pediatric patients who d eveloped pulmonary hypertension (high blood pressure in the lungs) imm ediately after cardiopulmonary bypass and surgical repair.