Interactions between the enhanced recovery after surgery pathway and risk factors for lung infections after pulmonary malignancy operation.

Background: Lung infection is a common complication after thoracic surgery and can lead to severe consequences. Our study was designed to explore the risk factors for postoperative lung infections (POLI) following pulmonary malignancy operation and assess the protective effect of enhanced recovery after surgery (ERAS) and their potential interactive relationships.

Methods: A retrospective study included 1,768 patients who underwent surgery between 2013 and 2017 in Ruijin Hospital, Shanghai Jiaotong University School of Medicine was performed. Uni- and multivariate analyses were performed to identify risk factors. Andersson's model was applied to evaluate the additive interaction between these factors.

Results: Smoking [95% confidence interval (CI): 1.178-2.198], preoperative heart disease (95% CI: 1.448-4.091), and massive intraoperative blood loss (95% CI: 1.568-3.674) were independent risk factors for postoperative lung infections (POLI), whereas ERAS implementation was protective (95% CI: 0.249-0.441). Interaction analyses indicated that non-ERAS was reciprocally independent with smoking and surgical procedure. It had a synergistic interaction with heart disease [attributable proportion due to interaction (AP) =0.540 (95% CI: 0.179-0.901), synergy index (S) =2.580 (95% CI: 1.016-6.551)], and poor lung function [AP =0.395 (95% CI: 0.016-0.775)], as well as a tendency of antagonistic interaction with blood loss.

Conclusions: Intraoperative blood loss, heart disease, and smoking are independent risk factors of POLI. ERAS implementation is a protective factor and is firstly verified to be more effective on reducing POLI in patients with heart diseases, poor lung function, and less intraoperative blood loss. We provide evidences to implement ERAS and a clue of the most optimal indications for ERAS.