Effect of residual lung expansion on pulmonary function after lobectomy.

Objectives: Pulmonary function after lobectomy is often higher than what is predicted. This occurrence could be related to postoperative expansion of the residual lung. The study aim was to determine if residual lung expansion affects pulmonary function after lobectomy.

Methods: The participants in this retrospective study were 142 patients who had undergone lobectomy via video-assisted thoracic surgery. Computed tomography and pulmonary function tests were performed preoperatively and 1 year postoperatively. Three-dimensional computed tomography volumetry was performed to assess lung volumes preoperatively and postoperatively, and the predicted postoperative forced expiratory volume in 1 s was calculated. The residual lung expansion ratio was defined as the postoperative-to-preoperative residual lung volume ratio, and the postoperative forced expiratory volume in 1 s ratio was defined as the measured-to-predicted postoperative forced expiratory volume in 1 s ratio. The effect of the residual lung expansion ratio on the postoperative forced expiratory volume in 1 s ratio as well as the factors affecting the postoperative forced expiratory volume in 1 s ratio were evaluated.

Results: The median residual lung expansion ratio was 1.17 (interquartile range: 1.10-1.24), and the median postoperative forced expiratory volume in 1 s ratio was 1.13 (interquartile range: 1.04-1.21). The residual lung expansion ratio significantly affected postoperative forced expiratory volume in 1 s ratio (p < 0.001).

Conclusion: After lobectomy, better residual lung expansion was associated with improved postoperative pulmonary function.