Influence of bulla volume on postbullectomy outcome.

Abstract

To quantify the contribution of the resected volume and the presence of associated, functionally significant emphysema to the postoperative improvement of pulmonary function after resection of giant lung bullae. Patients undergoing elective surgery for giant bullae who had had complete pulmonary function and radiographic studies performed were reviewed retrospectively. All 25 patients underwent surgery at the thoracic surgery unit of the University of Pisa, Pisa, Italy. Pulmonary function was assessed before and 12 months after surgery. On the chest radiograph, the location of bullae, and the signs of compression and emphysema were evaluated. The radiographic total lung capacity (TLC(x-ray)) and the volume of bullae were measured according to the ellipse method. Postoperatively, functional and radiographic changes were analyzed. The percentage change in forced expiratory volume in 1 s (Delta FEV(1)%) after surgery was the main outcome measure. The influence of factors related to emphysema and bulla volume on the functional improvement postbullectomy was assessed by stepwise multiple regression. Before surgery, the TLC(x-ray) overestimated the TLC measured by nitrogen washout, with a mean difference between the two measurements of 1.095 L. A close relationship was found between the TLC(x-ray) and the plethysmographic TLC (n=6; r=0.95). After surgery, dyspnea lessened (P<0.05) and FEV(1) increased (P<0.01). Statistically, the radiographic bulla volume was the single most important factor determining the Delta FEV(1)% (r=0.80, P<0.0001). These findings suggest that the preoperative size of bullae is the most important contributor to the improvement in ventilatory capacity after bullectomy, and that it is possible to predict the expected increase of postoperative FEV(1) from preoperative bulla volume.