REDUCED TRANSPLANT LUNG-VOLUMES AFTER SINGLE-LUNG TRANSPLANTATION FORCHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Single lung transplantation is now an extremely successful option for the treatment of end-stage chronic obstructive pulmonary disease (COPD ). This procedure involves placing a normal sized lung in a hyperinfla ted hemithorax. Preliminary observations of these patients suggest tha t the transplanted lung volume is smaller than expected and often the native (COPD) lung increases in volume. The purpose of this investigat ion was to quantify the volume contributions of the transplant and nat ive lung to the total lung capacity. In seven patients who underwent s ingle lung transplant for end-stage COPD the transplant and native lun g volumes were measured by computer-analyzed planimetry immediately af ter transplant and the following 6 mo post-transplant. The transplant lung volume was smaller than predicted immediately after transplant at only 33 +/- 5% (mean +/- SD) of predicted TLC. This did not change si gnificantly over the next 6 mo. Native lung volume increased following transplant to 74 +/- 19% predicted TLC at 1 mo and 80 +/- 16% at 6 mo . Five of the seven patients subsequently underwent measurement of ple ural pressures at TLC. The mean static pleural pressure at TLC was low at -16 +/- 5.1 cm H2O. in summary, following single lung transplantat ion for COPD the transplanted lung is significantly restricted. We con clude that the likely mechanism of this restriction is due to low tran spulmonary pressure generation.