Hepatopulmonary (hep-uh-toe-POOL-moe-nar-e) syndrome is an uncommon condition that affects the lungs of people with advanced liver disease. Hepatopulmonary syndrome is caused by blood vessels in the lungs expanding (dilating) and increasing in number, making it hard for red blood cells to properly absorb oxygen. This leaves the lungs unable to deliver adequate amounts of oxygen to the body, which leads to low oxygen levels (hypoxemia).
Exactly how the liver disease is linked to the lung condition isn't yet known. A liver transplant is the only cure for hepatopulmonary syndrome.