The hepatopulmonary syndrome (HPS) has been defined as the triad of liver disease, arterial hypoxemia, and intrapulmonary vascular dilatation that causes right-to-left shunting of blood flow.^1,2 As in adults, HPS in children also occurs in many types of liver diseases and the prevalence of this complication may range from 5% to 29%.³ The clinical findings of the syndrome include varying signs and symptoms of liver disease, finger clubbing, shortness of breath, cyanosis, dyspnea, platypnea, and orthodeoxia. Arterial hypoxemia may be so severe (PaO₂ = 50 mm Hg while breathing room air) that continuous oxygen supplementation is required and is associated with poor outcome.^2,4 Several reports suggest that orthotopic liver transplantation can lead to complete resolution of severe hypoxemia.^3,5,6

Adult patients with HPS have been reported to have significantly higher exhaled nitric oxide (NO) levels compared with healthy controls and with cirrhotics without hypoxemia.^7,8 The mechanisms that lead to an increased production of exhaled NO are still unknown but this vasoactive gas seems to be involved in the pathogenesis of the hemodynamic abnormalities of this syndrome. To our knowledge this phenomenon has not been observed in children. The purpose of this report was to evaluate exhaled NO levels in a 6-year-old boy affected by HPS.

	CASE REPORT

A 6-year-old boy was referred to our hospital for the evaluation of liver transplantation attributable to HPS. At the age of 1 year the patient had growth, speech, and motor development delay. At 30 months he presented with altered liver function tests (serum glutamic-oxaloacetic transaminase . . . [Full Text of this Article]