Perioperative Lung Protection: General Mechanisms and Protective Approaches.

Postoperative pulmonary complications (PPCs) are one of the most important cause of perioperative morbidity and mortality in patients undergoing noncardiothoracic surgery, leading to increased hospital length of stay and mortality rate. The principal purpose of this review is to provide an overview of the perioperative lung protection strategies in patients undergoing elective noncardiothoracic surgery, informing clinicians on evidence-based perioperative care pathways. We also conducted a systematic review and meta-analysis of randomized controlled trials in noncardiothoracic surgery focusing on the following aspects: preoperative physiotherapy, intraoperative protective mechanical ventilation, postoperative prophylactic continuous positive airway pressure (CPAP) or high-flow nasal cannula (HFNC), and postoperative physiotherapy. Both preoperative physiotherapy (relative risk [RR], 0.49, 95% confidence interval [CI], 0.35-0.69, P < .01) and postoperative CPAP (RR, 0.53, 95% CI, 0.30-0.94, P = .029) reduced the incidence of PPCs. Intraoperative protective mechanical ventilation had unclear effects (RR, 0.90, 95% CI, 0.77-1.06, P = .22). No benefits were observed for HFNC (RR, 0.88, 95% CI, 0.70-1.11, P = .30) and physiotherapy regimens administered in the postoperative period only (RR, 0.89, 95% CI, 0.69-1.16, P = .40). Lung-protective strategies should be considered throughout the entire perioperative period. The prophylactic use of strategies initiated in the postoperative period only, such as physiotherapy, CPAP, or HFNC, offers limited benefits. Physiotherapy and patient training should be started early in the preoperative phase, and intraoperative protective mechanical ventilation should be titrated on an individual basis taking into account all the available evidence.