Pulmonary arteriovenous malformations are a well documented complication of superior cavopulmonary (Glenn) connections. We report the successful management of a case of severe hypoxemia in the early postoperative period of a patient who underwent the Fontan operation. The patient had previously been diagnosed with pulmonary arteriovenous malformations; the use of inhaled nitric oxide was followed up with reversal of life-threatening hypoxemia. At 6-month postoperative follow-up, the patient was asymptomatic with near normal aortic saturation.