Characterization and Prediction of Prolonged Air Leak After Pulmonary Resection: A Nationwide Study Setting Up the Index of Prolonged Air Leak

Abstract

The objective of this study was to better characterize prolonged air leak (PAL), defined as an air leak longer than 7 days, and to develop and validate a predictive model of this complication after pulmonary resection. All lung resections entered in Epithor, the French national thoracic database (French Society of Thoracic and Cardiovascular Surgery), were analyzed. Data collected between 2004 and 2008 (n=24,113) were used to build the model using backward stepwise variable selection, and the 2009 data (n=6,813) were used for external validation. The primary outcome was PAL. Results of the predictive model were used to propose a score: the index of PAL (IPAL). Prevalence of PAL after pulmonary resection was 6.9% (n=1,655) in the development data set. In the final model, 9 variables were selected: gender, body mass index, dyspnea score, presence of pleural adhesions, lobectomy or segmentectomy, bilobectomy, bulla resection, pulmonary volume reduction, and location on upper lobe. In the development data set, the C-index was 0.71 (95% confidence interval [CI], 0.70 to 0.72). At external validation, the C-index was 0.69 (95% CI, 0.66 to 0.72) and the calibration slope (ie, the agreement between observed outcomes and predictions) was 0.874 (<1). A score chart based on these analyses has been proposed. The formula to calculate the IPAL is the following: gender (F=0; M=4)-(body mass index-24)+2×dyspnea score+pleural adhesion (no=0; yes=4)+pulmonary resection (wedge=0; lobectomy or segmentectomy=7; bilobectomy=11; bulla resection=2; volume reduction=14)+location (lower or middle lobe=0; upper=4). Surgeons can easily use the well-validated model to determine intraoperative preventive measures of PAL.