A lung transplant is a surgical procedure that is performed on patients who are suffering from end-stage lung disease, an irreversible condition that can result from a number of disorders. A lung transplant is performed to replace a lung or pair of lungs that is unable to perform adequate gas exchange. This may be the result of end-stage lung diseases, such as severe cases of emphysema, pulmonary fibrosis, cystic fibrosis, and pulmonary hypertension.
To become a candidate for lung transplant, a patient will meet with a pulmonologist to discuss the advantages and disadvantages of the procedure. Factors that must be weighed include quality of life and life expectancy. Because post-operative care requires a great deal of support, friends and family should be involved with the decision process. After the patient undergoes several tests and exams, his or her case will be presented to a committee of specialists for review. Depending on the patient’s condition, the committee will decide whether transplantation is a suitable option. If the committee decides not to accept the patient as a candidate, further tests or an alternate therapy may be recommended. Once on the list, the candidate will be placed on the United Network for Organ Sharing. The method of selection will be explained in detail to the patient. While on the waiting list, patients and the transplant team will be in close contact.
A single lung transplant is most clearly indicated for patients with restrictive lung disease. Advantages are the relative simplicity of the surgical procedure, which avoids systemic anticoagulation and cardiopulmonary bypass; the greater range acceptable for donor/recipient size match; and the optimal use of organs with the heart (and the contralateral lung) available for other recipients. Disadvantages include the possibility of ventilation/perfusion mismatch between the native and transplant lungs and poor healing of the bronchial anastomosis. Wrapping of the bronchial anastomosis with omentum has ameliorated but not eliminated the latter problem. A double lung transplant removes all diseased lung tissue and theoretically is applicable in all patients who have no irreversible cardiac abnormality. However, division of the donor bronchial arteries and bronchocoronary collaterals makes tracheal healing problematic.
Advantages of double lung and heart-lung transplantation are the removal of all potentially diseased tissue from the thorax and, for heart-lung transplantation, a more dependable healing of the tracheal anastomosis because coronary-bronchial collaterals are present within the heart-lung block. Disadvantages are the more extensive nature of the operations, with heart-lung replacement requiring cardiopulmonary bypass, the close match necessary for thoracic size, the use of two or three donor organs for one recipient, and, in some cases, the replacement of a normal heart with one that may develop posttransplant dysfunction. Indications for heart-lung transplantation are pulmonary vascular disease or diffuse parenchymal lung disease in which removal of all lung tissue is indicated (eg, certain cases of cystic fibrosis). When there is no intrinsic or secondary cardiac abnormality, the native heart of the heart-lung transplant recipient can be a donor organ for cardiac transplantation.
When a donor lung becomes available, time is critical. The lung must be transplanted into the patient receiving the organ within 4 to 6 hours. A team of surgeons and anesthesiologists performs an operation to remove the lung from the donor. Additional surgical teams may be present to remove other organs. After the lung is removed from the donor, it is preserved and packed for transport. Although the donor is brain dead, this procedure is treated like any other operation using standard surgical practices and sterile techniques. Once the operation is complete and the incisions are closed, the donor's body is prepared for funeral or cremation. Organ procurement surgery respects the body and an open casket funeral is possible if desired. Typically, both lungs are removed from the donor together. If the recipient is in need of a double lung transplant, both lungs will be transplanted. Otherwise, the lungs are usually separated after they are removed from the donor and used for two single lung transplant recipients.
In the meantime, a recipient is located and prepared for surgery as well. Preparation involves administration of general anesthesia, and placement on an artificial breathing machine. The transplant of the lung begins with removal of the diseased lung and the blood vessel attachments to the heart and large airway (bronchus). When the lung is placed within the recipient, the blood vessels and bronchus from the donor lung must now be connected to the recipient's corresponding blood vessels and bronchus. Next, the blood flow and airflow are restored. After the transplant is complete the incision is closed. The patient will begin recovery in the intensive care unit (ICU).
When a double lung transplant is performed, it is much like two single lung transplants. The lung that is more diseased is transplanted first and then the less diseased lung is transplanted. Careful monitoring will take place in a recovery room immediately following the surgery and in the patient's hospital room. Patients must take immunosuppression, or anti-rejection, drugs to reduce the risk of rejection of the transplanted organ. The body considers the new organ an invader and will fight its presence. The anti-rejection drugs lower the body's immune function in order to improve acceptance of the new organs. This also makes the patient more susceptible to infection. Frequent check-ups with a physician, including x ray and blood tests, will be necessary following surgery, probably for a period of several years.
The outcome of lung transplantation can be measured in survival rates, and also in improved quality of life for recipients. Studies have reported improved quality of life after lung and heart-lung transplants. One study showed that at the two-year follow-up period, 86% of studied recipients reported no limitation to their activity. Demonstration of normal results for patients may include quality of life measurements, as well as testing to ensure lack of infection and rejection.
Fighting rejection is an ongoing process. The body's immune system considers the transplanted organ as an invader (much like an infection) and may attack it. To prevent rejection, organ transplant patients must take anti-rejection (immunosuppression) drugs (such as cyclosporine and corticosteroids) that suppress the body's immune response and reduce the chance of rejection. As a result, however, these drugs also reduce the body's natural ability to fight off various infections.