Respiratory failure may be caused by several types of pulmonary dysfunctions, including parenchymal disease, a pulmonary embolism, and emphysema. However, the most common diseases that lead to lung transplantation are chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), cystic fibrosis (CF), alpha-1 antitrypsin (AAT) deficiency, and idiopathic pulmonary arterial hypertension (IPAH). COPD, along with emphysema, is a progressive disease that limits the airflow to and from the lungs, which in turn causes dyspnea; it is also the most common reason for lung transplantation in adults. IPF is also a progressive lung disease in which the interstitium of the lungs scars over time. CF is the most common reason for lung transplantation in children, and it is an autosomal genetic disease characterized by a buildup of thick mucus in the lungs that then leads to numerous serious infections. AAT deficiency is a genetic condition that increases the risk for lung diseases such as COPD; this risk increases dramatically with tobacco use. Finally, IPAH is characterized by an increase in the pressure in the pulmonary vasculature.
Prior to transplantation, both the donor and the recipient must meet certain prerequisites. First of all, the blood types must be matched. Then, the size of the transplant must be considered; the donated lung(s) must be of sufficient size to permit adequate oxygenation of the patient while fitting into the recipient’s chest cavity. On the other hand, the recipient must show signs of end-stage lung disease, all other viable options must have failed, and he/she must have no other chronic medical conditions. Necessary medical testing for these potential transplant donors and recipients include blood and tissue typing, chest x-rays, pulmonary function tests, and ventilation/perfusion lung scans. As of 2005, there is also a lung allocation score, developed by the United Network for Organ Sharing (UNOS), which takes several health measures of the patients into account. This system replaced the “first-come, first-serve” basis for transplantation.Want an expert to write a paper for you Talk to an operator now
There are four types of lung transplants. Firstly, there are the single-lung and double-lung transplantations. In a single-lung transplant, the more diseased lung is removed (if both are equally diseased the right one is taken so the heart does not obstruct the procedure) and the donor lung is transplanted. These transplants are generally used for patients suffering from emphysema, IPF, or IPAH, but they are not utilized in patients with infectious lung disease. In a double-lung transplant, both lungs are replaced by lungs from a single donor. Patients with disease caused by infection usually receive double-lung transplants as well as children suffering from CF; however, patients suffering from emphysema or IPAH may also undergo this type of transplant. Since both lungs come from a single donor in this case, wait times may unfortunately be prolonged. Generally, donor lungs are obtained from patients who have met the medical criteria for “brain death,” while their heart functions to maintain organ viability. Patients who are too ill to undergo complete cadaveric lung transplantation may be candidates for single or double lobar transplantation. Bilateralliving-donor lobar lung transplantation, in which two healthydonors donate their right or left lower lobes, provides greater organ availability. This type of transplantation is not done for emphysema and is usually reserved for patients with CF, IPF, or IPAH.
Then, there is also the heart-lung transplant. Some patients in need of a lung transplant may also be suffering from severe cardiac disease and need a new heart as well. The three organs needed can either come from one donor, which has almost double the wait time than a double-lung transplant, or from several donors, which is known as a “domino transplant.” In this case, the new heart and lungs are transplanted into the patient and then the old heart is removed and transplanted into another patient. This is the rarest form of lung transplantation.
The two major complications leading to death after transplantation are rejection and infection. Transplant rejection is most common within the first six months after the procedure. Symptoms include fever, chest congestion, dyspnea, and pain around the new lung. The most common complication within the first year of lung transplantation is primary graft dysfunction, and after the first year it is chronic graft dysfunction due to bronchiolitis obliterans syndrome (BOS). The medications used to prevent rejection may weaken the patient’s immune system, allowing for infections to occur. Long-term use of immunosuppressive medications can also cause diabetes and increase the risk of cancer. The nature of the underlying disease that caused the need for transplantation most significantly influences mortality rate. For example, first year mortality is the highest for IPAH and the lowest for COPD, while mortality after ten years is the highest for COPD and the lowest for CF and AAT deficiency. Also, the median survival for single-lung recipients is two years less than that for double-lung recipients.
Even in the absence of other problems, transplanted lungs begin to show signs of failure after about five years. Until then there usually is no need for a change in lifestyle unless the patient, for example, was using alcohol and tobacco. Some patients will need to go through pulmonary rehabilitation, a program including exercise and counseling. Overall, lung transplantation is quite an expensive treatment with only marginal gains in quality-adjusted life years for most recipients (patients suffering from post-operative BOSsee little to no gains in quality-adjusted life years). The number of lung transplants performed each year will not increase until organ availability increases.