Increased Effective Lung Volume Following Lung Volume Reduction Surgery in Emphysema

Study objectives Lung volume reduction surgery (LVRS) for emphysema has a variable effect on spirometry with improvement linked to increases in lung elastic recoil. The mechanism by which recoil increases following LVRS has not been described completely. This study examines preoperative and postoperative pulmonary function to describe a mechanism for changes in airflow obstruction. Design Change in pulmonary function following LVRS. Setting Public teaching hospital in Australia. Patients Patients with severe emphysema and pulmonary function measurements made before and after LVRS. Measurements Routine pulmonary function testing performed with ventilated lung alveolar volume (Va) derived from the gas transfer measurement used as a proxy for the effective lung volume. Results Pulmonary function tests from 36 consecutive patients with measurements made at the same laboratory were analyzed. The mean FEV 1 was 29.1% predicted presurgery and increased following LVRS from 0.900 L (SD, 0.427 L) to 1.283 L (SD, 0.511 L; p 1 correlated well with the change in Va ( r = 0.63). The change in FEV 1 in those patients whose Vas did not increase (n = 7) was not significant. Conclusions The increase in Va reflects an increase of functional or ventilating lung volume and is associated with an improvement in spirometry following LVRS.