EIT-guided individualized PEEP titration versus conventional lung-protective ventilation to prevent pulmonary complications in laparoscopic bariatric surgery: a study protocol for a randomized controlled trial

Obese patients face significantly elevated risks of postoperative pulmonary complications (PPCs), yet conventional fixed-level positive end-expiratory pressure (PEEP) ventilation often fails to address their heterogeneous respiratory mechanics. Robust evidence is lacking to guide optimal PEEP in mechanically ventilated obese patients, in whom the optimal PEEP exhibits considerable interindividual variability. While electrical impedance tomography (EIT)-guided PEEP titration demonstrates potential for optimizing alveolar recruitment and ventilation-perfusion matching, its clinical efficacy in reducing PPCs following laparoscopic bariatric procedures remains unestablished. This randomized controlled trial (RCT) rigorously evaluates whether a strategy combining standardized recruitment maneuvers (RMs) with EIT-guided individualized PEEP reduces the incidence of PPCs within 72 h postoperatively compared to a strategy combining RMs with fixed PEEP (8 cmH₂O). This study is a prospective, single-center, single-blind, randomized controlled clinical trial. Patients scheduled for laparoscopic bariatric surgery will be selected and randomly assigned to either the Group P or Group C. Group P will be ventilated using the PEEP value determined by EIT, while Group C will be ventilated with a fixed PEEP value of 8 cmH2O.The primary outcome is the incidence of postoperative pulmonary complications (PPCs) within 72 h after surgery. While previous studies suggest that individualized PEEP may improv oxygenation, reduce atelectasis, and optimize ventilation/perfusion (V/Q) matching, its clinical impact on PPCs in laparoscopic bariatric surgery remains uncertain. This RCT tests whether RMs with EIT-guided individualized PEEP reduce PPCs compared to RMs with fixed PEEP (8 cmH₂O), thereby isolating the effect of individualized PEEP selection. This study will determine whether EIT-guided individualized PEEP offers clinical benefit over fixed PEEP, potentially supporting further investigation in larger multicenter settings. This study was registered on clinicaltrials.gov (NCT07207772).