Effects of intraoperative PEEP on postoperative pulmonary complications in high-risk patients undergoing laparoscopic abdominal surgery: study protocol for a randomised controlled trial.

Postoperative pulmonary complications (PPCs), strongly associated with higher mortality risk, can develop in up to 58% of patients undergoing abdominal surgery. More and more evidence shows that the use of a lung-protective ventilation strategy has a lung protection effect in patients undergoing abdominal surgery, however, the role of positive end-expiratory pressure (PEEP) during the intraoperative period in preventing PPCs for laparoscopic surgery is not clearly defined.A total of 208 patients with a high risk of PPC, undergoing laparoscopic abdominal surgery, will be enrolled and randomised into a standard PEEP (6-8 cm HO) group and a low PEEP (≤2 cm HO) group. Both groups will receive a fraction of inspired oxygen of 0.50 and a tidal volume of 8 mL/kg ideal body weight (IBW). Standard perioperative fluid management and analgesic treatments are applied in both groups. The primary end point is PPC within 7 days after surgery. Secondary end points are the modified Clinical Pulmonary Infection Score, postoperative extrapulmonary complications, postoperative surgical complications, intensive care unit length of stay, hospital length of stay, 30-day mortality.The study was approved by the Ethics Committee of Zhejiang Provincial People's Hospital (People's Hospital of Hangzhou Medicine College) (registration number KY2018026) on 22 October 2018. The first participant was recruited on 15 April 2019 and the estimated completion date of the study is October 2021. The results of this trial will be submitted to a peer-reviewed journal.http://www.chictr.org.cn, ID: ChiCTR1800019865. Registered on 2 December 2018; preresults.