REBOUND PULMONARY-HYPERTENSION AFTER INHALATION OF NITRIC-OXIDE

Background. We describe the hemodynamic response to initiation and wit hdrawal of inhaled nitric oxide (NO) in infants with pulmonary hyperte nsion after surgical repair of total anomalous pulmonary venous connec tion. Methods. Between January 1, 1992, and January 1, 1995, 20 patien ts underwent repair of total anomalous pulmonary venous connection. Ni ne patients had postoperative pulmonary hypertension and received a 15 -minute trial of inhaled NO at 80 parts per million. Five of these pat ients received prolonged treatment with NO at 20 parts per million or less. Results. Mean pulmonary artery pressure decreased from 35.6 +/- 2.4 to 23.7 +/- 2.0 mm Hg (mean +/- standard error of the mean) (p = 0 .008), and pulmonary vascular resistance decreased from 11.5 +/- 2.0 t o 6.4 +/- 1.0 U . m(2) (p = 0.03). After prolonged treatment with NO, pulmonary artery pressure increased transiently in all patients when N O was discontinued. Conclusions. After operative repair of total anoma lous pulmonary venous connection, inhaled NO selectively vasodilated a ll patients with pulmonary hypertension. Withdrawal of NO after prolon ged inhalation was associated with transient rebound pulmonary hyperte nsion that dissipated within 60 minutes. Appreciation of rebound pulmo nary hypertension may have important implications for patients with pu lmonary hypertensive disorders when interruption of NO inhalation is n ecessary or when withdrawal of NO is planned.