Background: The aim of this study was to evaluate the influence of chronic obstructive pulmonary diseases (COPD) on postoperative pulmonary function and to elucidate the factors for decreasing the reduction of pulmonary function after lobectomy.
Methods: We conducted a retrospective chart review of 521 patients who had undergone lobectomy for lung cancer at Chiba University Hospital between 1990 and 2000. Forty-eight patients were categorized as COPD, defined as percentage of predicted forced expiratory volume at 1 second (FEV1) less than or equal to 70% and percentage of FEV1 to forced vital capacity less than or equal to 70%. The remaining 473 patients were categorized as non-COPD.
Results: Although all preoperative pulmonary function test data and arterial oxygen tension were significantly lower in the COPD group, postoperative arterial oxygen tension and FEV1 were equivalent between the two groups, and the ratio of actual postoperative to predicted postoperative FEV1 was significantly better in the COPD group (p < 0.001). With multivariable analysis, COPD and pulmonary resection of the lower portion of the lung (lower or middle-lower lobectomies) were identified as independent factors for the minimal deterioration of FEV1. Actual postoperative FEV1 was 15% lower and higher than predicted, respectively, in the non-COPD patients with upper portion lobectomy and the COPD patients with lower portion lobectomy. Finally, we created a new equation for predicting postoperative FEV1, and it produced a higher coefficient of determination (R(2)) than the conventional one.
Conclusions: The postoperative ventilatory function in patients with COPD who had lower or middle-lower lobectomies was better preserved than predicted.