A lung transplant is a life-saving surgical procedure performed to replace one or both diseased lungs with a healthy lung. The lungs are responsible for oxygenating the blood supply within the body. A person who needs a lung transplant may be suffering from lung disease such as emphysema, sarcoidosis, pulmonary hypertension or cystic fibrosis. Even though most people have two lungs, one healthy lung is usually able to function in place of two, allowing for a normal, healthy and active life. Therefore, a pair of lungs can be transplanted into two different recipients, saving two lives. A double-lung transplant, as well as a combination heart-lung transplant, can also be done for some patients.