Effects of Individualized Positive End-Expiratory Pressure on Patients Undergoing One-Lung Ventilation During Thoracic Surgery: A Systematic Review and Meta-Analysis.

Objective: To evaluate the impact of individualized positive end-expiratory pressure (PEEP) versus fixed PEEP on postoperative pulmonary complications (PPCs), intraoperative oxygenation, and respiratory mechanics in thoracic surgery. One-lung ventilation (OLV) poses potential risks of PPCs. PEEP may mitigate lung injury, but the optimal PEEP level remains uncertain.

Methods: We searched PubMed, Embase, Web of Science, and Cochrane for randomized controlled trials (RCTs) comparing individualized PEEP versus fixed PEEP during OLV published up to December 2024. The primary outcome was the occurrence of overall PPCs during hospitalization. Secondary outcomes included postoperative hypoxemia, atelectasis, pneumonia, acute respiratory distress syndrome (ARDS), intraoperative oxygenation, dynamic compliance, driving pressure, and hospital length of stay. Risk ratios (RRs) and mean differences were calculated using the DerSimonian-Laird method. Study quality was evaluated using the Cochrane Risk of Bias tool version 2 for RCTs trials. Trial sequential analysis (TSA) was used to assess result reliability.

Results: Six RCTs (with a total of 1,844 patients) were included, with 5 studies (1,814 patients) reporting PPCs. Individualized PEEP did not significantly reduce overall PPCs (RR, 0.78; 95% confidence interval, 0.59-1.03; p = 0.08), hypoxemia, pneumonia, or atelectasis; however, it reduced postoperative ARDS and improved intraoperative oxygenation and lung compliance. TSA revealed that the current sample size of 1,814 in PPCs was below the required 3,660, and that the z-curve did not cross the TSA monitoring boundaries.

Conclusions: Individualized PEEP in thoracic surgery may improve intraoperative oxygenation, pulmonary mechanics, and reduce postoperative ARDS but does not significantly lower overall PPCs. Overall, the quality of the evidence is low and inconclusive, and further investigation is warranted.