Respiratory dysfunction and pulmonary disease in cirrhosis and other hepatic disorders

End-stage liver disease and its complications are a leading cause of death among adults in the United States, and thousands of patients await liver transplantation. The liver plays a central role in health and homeostasis and thus the diseased liver leads to many deleterious effects on multiple organ systems, including the pulmonary system. We review the general effects of cirrhosis on the respiratory system, including mild hypoxemia, atelectasis, and hepatic hydrothorax. Cirrhosis is associated with 2 unique entities that affect the pulmonary vasculature: hepatopulmonary syndrome and portopulmonary hypertension. Hepatopulmonary syndrome, which is found in approximately 20% of patients awaiting liver transplantation, refers to the triad of hepatic dysfunction, hypoxemia, and intrapulmonary vascular dilations, and responds well to liver transplantation. In portopulmonary hypertension, cirrhosis and portal hypertension lead to pulmonary arterial hypertension, and portopulmonary hypertension has been considered a contraindication for transplantation. Currently, patients must have mild to moderate pulmonary hypertension to be considered for transplantation, and may still require long-term therapy with vasodilators to prevent right-ventricular failure and, consequently, failure of the newly transplanted liver allograft.