Emergency Surgery and Preoperative Frailty with Postoperative Pulmonary Complications in Elderly Patients Undergoing Major Abdominal Surgery

This single-center retrospective study investigated associations of emergency surgery and preoperative frailty with postoperative pulmonary complications (PPCs) in elderly major abdominal surgery patients. Of 350 initially recruited patients at The First Hospital of Jiaxing (Mar 2024-Mar 2025), 294 were eligible after screening and stratified into PPCs (n = 53) and non-PPCs (n = 241) groups. Multivariate logistic regression identified PPC predictors; interaction analysis evaluated their joint effect. Receiver operating characteristic curves evaluated the predictive performance of individual indicators and the combined model. Between-group disparities were identified in age, American Society of Anesthesiologists class, smoking, diabetes, emergency surgery, preoperative frailty, assess respiratory risk in surgical patients in Catalonia (ARISCAT) score, infusion volume, and postoperative day 1 visual analogue scale (VAS) pain score (all P < 0.05). The PPCs group had higher rates of emergency surgery (P = 0.002) and preoperative frailty (P < 0.001). Patients with both emergency surgery and preoperative frailty had a 35.7% PPCs rate (P < 0.001). Multivariate logistic regression identified age, ARISCAT score, postoperative day 1 VAS pain score, emergency surgery, and preoperative frailty as independent factors associated with PPCs (all P < 0.05). Emergency surgery and preoperative frailty were both independent risk factors for PPCs, and their combination showed a significant multiplicative interaction [interaction odds ratio (OR) = 1.363, 95% confidence interval (CI): 1.010-1.832, P = 0.044], yielding a joint OR notably higher than either factor alone. A combined model including age, emergency surgery, preoperative frailty, ARISCAT score, and postoperative day 1 VAS score achieved an area under the curve of 0.894 (95% CI: 0.833-0.956), which was higher than any single indicator (all P < 0.05). Preoperative frailty was associated with PPCs more strongly than emergency surgery in this cohort, and the two factors showed a joint association; assessment and intensified care are recommended.