Methylene Blue in the Hepatopulmonary Syndrome

To the Editor: The hepatopulmonary syndrome, which is characterized by hypoxemia due to intrapulmonary shunting or a ventilation-perfusion mismatch (or both), develops in some patients with liver cirrhosis. Patients with this syndrome have no apparent parenchymal lung disease but may have orthodeoxia, the unusual finding of increased hypoxemia with the change from a supine to a standing position.1 Increased endogenous production of nitric oxide may play a part in the hyperdynamic circulation that is typical of patients with the hepatopulmonary syndrome. An increased concentration of exhaled nitric oxide has recently been reported in one such patient; hypoxemia resolved and the . . .