A heart-lung transplant is a procedure carried out to replace both heart and lungs in a single operation. Due to a shortage of suitable donors it is a rarely done prcedure, for instance only about 100 such transplants are performed each year in the USA.
Most candidates for heart-lung transplants have life-threatening damage to both their heart and lungs. In the USA, most prospective candidates have between 12 and 24 months to live. At any one time, there are about 250 people on the United Network for Organ Sharing (UNOS) in the USA - about 40 of those will die before a suitable donor is foud.
Conditions which may necessitate a heart-lung transplant include:
Candidates for a heart-lung transplant are usually required to be:
The patient is anesthetised. When the donor organs arrive, they are checked for fitness - any organs that show signs of damage are discarded and the operation cancelled. Some patients are concerned that their organs will be removed and the donor organs not suitable. Since this is a possibility, it is standard procedure that the patient is not operated on until the donor organs arrive and are judged suitable, depite the time delay this involves.
Once suitable donor organs are present, the surgeon makes an incision starting above and finishing below the sternum, cutting all the way to the bone. The skin edges are retracted to expose the sternum. Using a bone saw, the sternum is cut down the middle. Rib spreaders are inserted in the cut, and spread the ribs to give access to the heart and lungs of the patient.
The patient is connected to a heart-lung machine, which circulates and oxygenates blood. The surgeon removes the failing heart and lungs. Most endavour to cut blood vessels as close a possible to the heart to leave room for trimming, especially if the donor heart is of a different size than the original organ.
The donor heart and lungs are positioned and sewn into place. As the donor organs warm up to body tempreature, the lungs begin to inflate. The heart may fibrillate at first - this occurs because the cardiac muscle fibres are not contracting synchronously. Internal paddles can be used to apply a small electric shock to the heart to restore proper rhythm.
Once the donor organs are functioning normally, the heart-lung machine is withdrawn, and the chest is closed.
Most patients spend several days in intensive care after the operation. If there are no complications (eg infection, rejection), some are able to return home after just 2 weeks in hospital. Patients will be given anti-rejection drugs, and antibiotics to prevent infection. A schedule of frequent follow up visits is necessary.
National Heart, Lung and Blood Institute (NHLBI) (http://www.nhlbi.nih.gov)