Correlation of unilateral thoracoscopic lung volume reduction with improvement in lung function and exercise performance in patients with severe pulmonary emphysema

This study was conducted to investigate the correlation of thoracoscopic lung volume reduction to changes in pulmonary function and exercise performance in patients with pulmonary emphysema. Unilateral thoracoscopic lung volume reduction treatment was performed in 30 patients with severe pulmonary emphysema. If large bullae were present, they were excised using an endoscopic stapling device, and the emphysematous pleura was contracted by neodymium:yttrium-aluminium-garnet laser to reduce the volume of nonfunctional lung air space. Pulmonary function and incremental exercise tests were performed before and at least 3 months after treatment. Follow-up functional evaluation showed a highly significant improvement in the forced expiratory volume in 1s (FEV₁), forced vital capacity, static compliance, and maximal oxygen uptake. The functional residual capacity as measured by the gas dilution method (FRC(gas)), was unchanged; however, it was found to be decreased significantly when measured by body plethysmograph (FRC(box)). Positive correlations existed between the reduction in FRC(box) and the increase in FEV₁ (r = 0.586, P = 0.0042) and maximal oxygen uptake (r = 0.550, P = 0.018). Pulmonary ventilation and exercise ability in patients with pulmonary emphysema were improved in a volume-dependent manner by thoracoscopic lung volume reduction. These findings indicate that patients with a preoperative trapped gas volume level exceeding 11 would be ideal candidates for thoracoscopic lung volume reduction.