ObjectiveTo describe the use of inhaled nitric oxide in the management of refractory postoperative chylothorax.DesignCase report.SettingA pediatric intensive care unit of a tertiary care children's hospital.PatientA neonate with refractory chylothoraces complicated by moderate pulmonary hypertension after a complicated arterial switch operation.InterventionsAdministration of inhaled nitric oxide through a ventilator circuit.Measurements and Main ResultsThe institution of inhaled nitric oxide at 20 ppm resulted in a marked reduction in chest tube drainage and a decrease in echocardiographically estimated pulmonary artery pressure from 50%-75% systemic to 30%-50% systemic. Chest tube drainage doubled when the nitric oxide was decreased to 10 ppm and, again, dramatically decreased after raising nitric oxide back to 20 ppm. After 8 days of nitric oxide therapy, the chest tube drainage ceased. Nitric oxide therapy was successfully discontinued 19 days after initiation, with no recurrence of chylothorax. There was no effect of nitric oxide on systemic blood pressure. Methemoglobin levels while on NO remained <1.7%.ConclusionConsideration may be given to the use of inhaled nitric oxide in the therapy of refractory chylothoraces complicated by central venous hypertension. (Crit Care Med 1999; 27:1022-1024)