The donor lung: conservation of a precious resource.

Lung transplantation became a reality in 1963 when Dr James Hardy performed the first successful single lung transplant in a patient with chronic pulmonary disease and bronchogenic carcinoma. His patient survived 18 days, eventually succumbing to renal failure. His opportunity for success was hampered by a lack of adequate immunosuppressive agents, limited perioperative monitoring, and a lack of adequate support systems such as haemodialysis. Over the next two decades numerous lung transplants were performed. Although all ended as failures, valuable information and experience accumulated in the areas of immune system alteration, diagnosis and treatment of rejection, and opportunistic infections. The role of prophylactic antibiotic regimens was better defined. Since the mid 1980s many of these issues have been resolved, and many centres currently perform lung transplantation with progressively better survival rates. The availability of cyclosporin as an immunosuppressive agent allowed reduced doses of corticosteroids to be used and has had a dramatic impact on the successful outcome of lung transplantation.The latest report from the United Network for Organ Sharing (UNOS) in the USA recognises 95 centres registered to perform heart-lung transplants and 91 to perform lung transplantation. As more centres have the technological expertise to perform transplantation, and as this technology expands to treat a wider range of chronic lung diseases, there has been an inevitable increase in the number of patients listed for transplantation and, consequently, significant prolongation of waiting times. This is a problem which is now aVecting all countries with active transplant programmes; in this paper these problems are discussed in relation to data for transplantation in the USA. Transplant physicians have constantly to analyse this fluctuation in waiting times. Patients must “get in” in the UNOS list at a time when they are significantly and irreversibly impaired by their chronic pulmonary disease, yet while still healthy enough to survive the prolonged wait. Although impossible to predict, the hope is that when the transplant actually occurs, the patient still preserves a minimum of strength and physical conditioning to survive the surgery. Even when many objective parameters are used in selection of transplant candidates, there is always a component of luck and conjecture in this process. Most transplant centres follow general criteria for the inclusion of patients on a waiting list. Patients with chronic obstructive lung disease are usually considered for transplantation when they are functionally disabled, reaching forced expiratory volume in one second (FEV1) of <20–25% of normal, when there is significant hypercapnia, hypoxaemia, or secondary pulmonary hypertension complicating the course of the disease, or when there is a rapid decline in functional parameters while receiving optimal medical treatment. Patients with pulmonary fibrosis have increased short termmortality when their FVC is <65% of normal and they fail to respond to corticosteroid agents. Patients with pulmonary fibrosis with a forced vital capacity (FVC) <65% of normal who have a low transfer factor (TLCO) of <30% predicted, and those becoming hypoxic with exertion have a poor prognosis and should be considered for transplantation. Patients with cystic fibrosis having an FEV1 of <30% of predicted, with either hypoxia or hypercapnia, or having a rapid decline in lung function with recurrent exacerbations should also be included. 6 Patients with severe primary pulmonary hypertension (mean PA >50 mm Hg) with increased central venous pressure and poor cardiac index (<2.5) who do not respond to vasodilators are at risk for increased mortality and are usually considered for single or double lung transplantation. Despite the careful use of all these criteria for listing patients at an appropriate time in the course of their illnesses, 15–20% of all patients listed for lung transplantation die while waiting for a suitable donor.