Classification and Risk-factor Analysis of Postoperative Cardio-pulmonary 
Complications after Lobectomy in Patients with Stage I Non-small Cell Lung Cancer

Background and objective There are incresing lung cancer patients detected and diagnosed at the intermediate stage when the pre-malignant or early lesions are amenable to resection and cure, owing to the progress of medical technology, the renewal of detection methods, the popularity of medical screening and the improvement of social health consciousness. The aim of this study is to investigate the risk factors of the occurrence of postoperative cardio-pulmonary complications in stage I non-small cell lung cancer (NSCLC) patients, based on routine laboratory tests, basic characteristics, and intraoperative variables in hospital. Methods The 421 patients after lobectomy in patients with stage I NSCLC at the West China Hospital of Sichuan University from January 2012 to December 2013 were included into the study and stratified into complication group and non-complication group, according to whether to occur postoperative cardio-pulmonary complications after lobectomy in 30 days. Results Of them, 64 (15.2%) patients were finally identified and selected into the complication group, compared with 357 (84.8%) in non-complication group: pneumonia (8.8%, 37/421) was the primary complication, and other main complications included atelectasis (5.9%, 25/421), pleural effusion (≥middle) (5.0%, 21/421), persistent air leak (3.6%, 15/421); The operation time (P=0.007), amount of blood loss (P=0.034), preoperative chronic obstructive pulmonary disease (COPD) (P=0.027), white blood cell (WBC) count (P<0.001), neutrophil-lymphocyte ratio (NLR) (P<0.001) were significantly different between the two groups. According to the binary logistics regression analysis, preoperative COPD (OR=0.031, 95%CI: 0.012-0.078, P<0.001) and WBC count (OR=1.451, 95%CI: 1.212-1.736, P