Hepatopulmonary syndrome is defined by the presence of liver disease, an increased alveolar-arterial gradient while breathing room air, and evidence for intrapulmonary vascular abnormalities. The clinical features of hepatopulmonary syndrome are the consequences of both hepatic and pulmonary dysfunction. More than 80 percent of patients present with symptoms of liver disease; the remainder experience dyspnea as their initial symptom. Hypoxia is a common finding.