Driving pressure-guided individualized PEEP versus fixed low PEEP in obese patients undergoing bariatric surgery: a randomized clinical trial

Obese patients are vulnerable to atelectasis, impaired oxygenation, and postoperative pulmonary complications (PPCs) during and after general anesthesia. Driving pressure-guided individualized positive end-expiratory pressure (PEEP) can improve intraoperative respiratory mechanics, but whether these physiological benefits translate into fewer PPCs in bariatric surgery remains uncertain.

In this single-center, parallel-group randomized clinical trial, 116 adults with obesity scheduled for elective laparoscopic bariatric surgery were randomized 1:1 to a driving pressure-guided individualized PEEP strategy or a conventional fixed low-PEEP strategy. All patients received volume-controlled ventilation with a tidal volume of 7 ml/kg predicted body weight and an inspired oxygen fraction of 0.50. After a standardized recruitment maneuver, the driving pressure group underwent stepwise PEEP titration to identify the PEEP level associated with the lowest driving pressure; the conventional group received fixed PEEP of 5 cm H₂O. The primary endpoint was the severity and incidence of PPCs within the first 5 postoperative days. Secondary endpoints included respiratory mechanics, oxygenation, hospital length of stay, postoperative nausea and vomiting, surgical site infection, and mortality.

All 116 randomized patients completed the trial. Any PPC occurred in 41 of 58 patients (70.7%) in the driving pressure group and 44 of 58 patients (75.9%) in the conventional group (odds ratio, 0.77; 95% CI, 0.33 to 1.79; P = 0.68). PPC severity scores were 1.0 ± 0.9 and 1.1 ± 0.8, respectively (mean difference, -0.10; 95% CI, -0.41 to 0.21; P = 0.53). Severe PPCs (grade >  = 3) occurred in 3 patients (5.2%) in each group. Compared with conventional ventilation, driving pressure-guided ventilation produced lower intraoperative driving pressure, higher dynamic compliance, and a higher PaO2/FiO2 ratio 1 h after surgical start; these physiological improvements were not accompanied by shorter hospital stay or fewer postoperative adverse events.

In obese patients undergoing laparoscopic bariatric surgery, a driving pressure-guided individualized PEEP strategy improved intraoperative respiratory mechanics and early oxygenation but did not reduce PPCs compared with conventional fixed low-PEEP ventilation. These findings suggest that optimizing respiratory-system driving pressure alone may be insufficient to improve short-term clinical pulmonary outcomes in this surgical population.