Predictors of pulmonary complications after bariatric surgery

Background: Postoperative pneumonia (PP) and respiratory failure (PRF) are known to be the most common nonwound complications after bariatric surgery. Our objective was to identify their current prevalence after bariatric surgery and to study the preoperative factors associated with them using data from the American College of Surgeons' National Surgical Quality Improvement Program. Methods: Patients undergoing bariatric surgery were identified from the National Surgical Quality Improvement Program (2006-2008), a multicenter, prospective database. Univariate analysis and multivariate logistic regression analysis were performed. Results: Of 32,889 patients, PP was diagnosed in 187 patients (.6%) and PRF in 204 patients (.6%). The overall 30-day morbidity rate was 6.4%, with PP and PRF accounting for 18.7%. The 30-day mortality rate was greater for the patients with PP and PRF than those without (4.3% versus .16% and 13.7% versus .10%, P < .0001). The hospital length of stay was also longer in patients with PP/PRF (P < .0001). On multivariate analysis, congestive heart failure (odds ratio 5.3, 95% confidence interval 1.20-23.26) and stroke (odds ratio 4.1, 95% confidence interval 1.42-11.49) were the greatest preoperative risk factors for PP. Previous percutaneous coronary intervention (odds ratio 2.8, 95% confidence interval 1.64-4.74) and dyspnea at rest (odds ratio 2.64, 95% confidence interval 1.13-6.13) were the factors most strongly associated with PRF. Bleeding disorder, age, chronic obstructive pulmonary disease, and type of surgery were risk factors for both (P < .05). Smoking also predisposed to PP, and diabetes mellitus, anesthesia time, and increasing weight also predisposed to PRF (P < .05 for all). Conclusion: Although PP and PRF are infrequent, they account for one fifth of the postoperative morbidity and are associated with significantly increased 30-day mortality. They can be predicted by various risk factors, emphasizing the importance of patient optimization and careful selection before bariatric surgery. (Surg Obes Relat Dis 2012;8:574-581.) (c) 2012 American Society for Metabolic and Bariatric Surgery. All rights reserved.