Background: Lower respiratory tract infection (LRTI) after tracheal intubation under general anesthesia poses a serious threat to worldwide health care systems, especially those in developing countries. However, a significant number of studies have found inconsistent results in their investigation of the corresponding risk factors. Methods: Relevant articles published up to September 2015 were retrieved from PubMed, Ovid, Embase, China National Knowledge Infrastructure, Chinese Biological Medical Database, China Science and Technology Journal Database, and Wanfang Data. The z test was used to determine the significance of the pooled odds ratio (OR). ORs and 95% confidence intervals were used to compare the risk factors of LRTI after intubation under general anesthesia. Results: Fifteen case-control studies that included 27,304 participants were identified. We identified the following variables as independent risk factors: duration of general anesthesia >3 hours (OR, 2.45), age >60 years (OR, 2.35), normal endotracheal tube (OR, 1.63), deep intubation (OR, 2.66), unpracticed intubation (OR, 2.61), postoperative extubation time >2 hours (OR, 3.76), smoking history (OR, 3.02), chronic respiratory disease history (OR, 2.30), incomplete extubation indication (OR, 3.54), thoracic or craniocerebral surgery (OR, 1.90), and emergent surgery (OR, 2.54). Conclusions: Eleven risk factors, including surgery, anesthesia, and health condition, were related to LRTI after intubation under general anesthesia. Given the limitations of this study, well-designed epidemiologic studies with a large sample size should be performed in the future. (C) 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
