Résumé : Background: In obese patients (OP), the best intraoperative ventilation strategy remains to be defined. Dynamic lung compliance (C dyn ) and dead space fraction are indicators of efficient ventilation at an optimal positive end-expiratory pressure (PEEP). Herein, we investigated whether intraoperative dynamic lung compliance optimization through PEEP manipulations affects the incidence of postoperative hypoxemia (SpO 2 < 90%) in OP undergoing laparoscopic bariatric surgery (LBS). Methods: This was a single-center, prospective, randomized controlled study conducted from July 2013 to December 2015. After obtaining institutional review board approval and informed consent, 100 OP undergoing LBS under volume-controlled ventilation (tidal volume 8 mL/kg of ideal body weight) were randomized according to the PEEP level maintained during the surgery. In the control group, a PEEP of 10 cm H 2 O was maintained, while in the intervention group, the PEEP was adapted to achieve the best dynamic lung compliance. Anesthesia and analgesia were standardized. The patients received supplemental nasal oxygen on the first postoperative day and were monitored up to the second postoperative day with a portable pulse oximeter. Results: Demographics were similar between groups. There was no difference in the incidence of hypoxemia during the first 2 postoperative days (control: 1.3%; intervention: 2.1%; p = 0.264). Conclusions: The incidence of postoperative hypoxemia was not reduced by an open-lung approach with protective ventilation strategy in obese patients undergoing LBS. A pragmatic application of a PEEP level of 10 cm H 2 O was comparable to individual PEEP titration in these patients. Trial Registration: Clinicaltrials.gov identifier, NCT02579798; https://clinicaltrials.gov/ct2/show/NCT02579798.