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Driving pressure-guided individualized PEEP versus fixed low PEEP in obese patients undergoing bariatric surgery: a
Xuelong Zhou1, Jialiu2, Jingming Zhu2
1Department of Anesthesiology, Women's Hospital of Zhejiang University, Hangzhou, China.
Purpose:
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.
Methods:
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.
Results:
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.
Conclusion:
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.
