In lung transplant surgery, someone with life-threatening respiratory problems is given one or two healthy lungs taken from a person who has died. If one lung is transplanted, the procedure is called a single-lung transplant. If both lungs are transplanted, it is a bilateral or double-lung transplant.
Lungs for transplantation usually come from young, healthy people who have had severe brain damage because of trauma or cardiac arrest (a stopped heart). Their lungs and other organs are maintained with life-support machinery.
Under certain circumstances, two living people can donate small parts of their lungs to one person in desperate need of a transplant. Each person donates one lobe (section) of a lung. This rare use of living donors is done in some cases because of a great shortage of suitable lungs from donors who have died. Entire lungs are never transplanted from a healthy living donor because of the high risk of complications. Living donor lung transplants are very uncommon.
Most lung donors have been healthy nonsmokers younger than 55. An extensive medical evaluation is done to make sure that the lungs are healthy and free of serious damage and disease. Following evaluation, the lungs are often judged unsuitable for transplantation.
Donors and recipients need to be about the same height, so the lungs will be the appropriate size. In addition, blood types are matched to reduce the risk that the recipient's immune system will attack a transplanted lung as a foreign object. This process is called organ rejection.
Relatively few lung transplants are done because of the general shortage of transplant donors and because so few donors meet the strict criteria for lung transplantation. The average wait for a lung transplant in the United States is just under two years. About 10% of those waiting die each year.
Potential donor organs usually are found through an organization called the United Network for Organ Sharing (UNOS). After matching for body size and blood type, people are selected to receive new lungs based on several criteria.