Exercise Limitation in Recipients of Lung Transplants

Lung transplantation is a viable option for improving survival and quality of life in selected patients with end-stage lung diseases such as chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, and cystic fibrosis.1 Following lung transplantation, there are substantial improvements in pulmonary function and a subsequent improvement in exercise capacity; however, peak exercise remains reduced to 40% to 60% of predicted values even up to 2 years after transplantation. Williams et al2 tested maximal exercise capacity in recipients of a single-lung transplant (SLT) (n=6) and in recipients of a double-lung transplant (DLT) (n=7) at 3 months and again at 1 to 2 years after transplantation. At 3 months after transplantation, peak oxygen consumption (V̇o2peak) was 46% of predicted values in the SLT group and 50% of predicted values in the DLT group. At 1 to 2 years after transplantation, there was no improvement in maximal oxygen consumption (V̇o2max) or maximal work capacity in either group, despite improvements in lung function and return to regular activities (ie, school or work) in most of the recipients of transplants. Evans et al3 compared whole-body exercise (cycling) in 9 recipients of SLT who were 5 to 38 months after transplantation versus a control group of subjects without known pathology or impairments. Measurements of V̇o2peak taken during cycling were reduced in the SLT group compared with the control group (P<.001) and were only 36.8%±3.1% (X̅±SD) of predicted values in the SLT group. This reduction in exercise capacity poses an interesting challenge to physical therapists. An understanding of the potential factors contributing to exercise limitation in this population, therefore, is imperative to prescribing an exercise program that emphasizes the appropriate body systems and leads to improvement in functional capacity of these people.