Supplementary Material for: Postoperative Pulmonary Complications after Surgery in Patients with Interstitial Lung Disease

Background: Patients with interstitial lung disease (ILD) have a high incidence of postoperative pulmonary complications (PPCs) after lung resection, but there is little data about these complications in ILD after other types of surgery. Objectives: The aim of this study was to examine the characteristics and predictors of PPCs after major surgery in patients with ILD. Methods: We included 336 patients with ILD who underwent major surgery between January 2005 and December 2010 at two tertiary hospitals in Korea. All types of surgery that had been performed under general anesthesia were included. Demographic characteristics, preoperative lung function, and operative conditions including anesthesia time and estimated blood loss were compared between patients with and without PPCs. Results: PPCs occurred in 37 patients (11%). Thirteen patients developed pneumonia, the most common PPC, and 11 had acute exacerbation of ILD. In multivariable analysis, BMI <23 (OR = 2.488, 95% CI: 1.084-5.710, p = 0.031), emergency surgery (OR = 23.992, 95% CI: 2.629-218.949, p = 0.005), lung surgery (OR = 5.090, 95% CI: 1.391-18.628, p = 0.014), and longer anesthesia time (OR = 1.595, 95% CI: 1.143-2.227, p = 0.006) were statistically significant risk factors. Conclusions: The incidence of PPCs detected over all surgeries was not as high as that reported for lung surgery alone in ILD patients. Lower BMI, emergency surgery, lung surgery, and longer anesthesia time were risk factors. Operative conditions as well as lung function should be considered in preoperative planning and management for ILD patients undergoing major surgery.