Intraoperative protective ventilation with or without periodic lung recruitment manoeuvres on pulmonary complications after major abdominal surgery (REMAIN-1): protocol for a randomised controlled trial

Introduction Postoperative pulmonary complications (PPCs) are frequent after abdominal surgery and significantly affect postoperative outcomes. Intraoperative protective ventilation (IPV) has been demonstrated to mitigate PPCs. However, the comparative effectiveness of two common IPV regimens-IPV with or without periodic lung recruitment manoeuvres (PLRM)-in preventing PPCs is unclear. This study aims to compare the effects of these two IPV regimens on PPCs.Methods and analysis This study is a prospective, double-blinded, randomised controlled trial. A total of 1060 patients at intermediate or high risk for PPCs, scheduled to undergo major abdominal surgery, will be enrolled and randomly assigned to receive either an IPV with PLRM (intensive IPV group) or an IPV without PLRM (moderate IPV group). Patients assigned to the intensive IPV group will receive positive end-expiratory pressure (PEEP) of 6-10 cm H2O with lung recruitment manoeuvres performed every 30 min. Patients in the moderate IPV group will receive the same level of PEEP without lung recruitment manoeuvres. Both groups will receive a tidal volume of 7 mL/kg predicted body weight and an inspired oxygen fraction of 0.3-0.4. The primary outcome is respiratory failure within the first 7 postoperative days. Secondary outcomes include other PPCs, extrapulmonary complications, unplanned admissions to the intensive care unit, length of postoperative hospital stay and mortality from any cause.Ethics and dissemination This protocol has been approved by the Ethics Committee of the Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China. The first participant was recruited on 9 October 2022, with an estimated completion date of 30 May 2025. The results of this trial are expected to be published in peer-reviewed journals.Trial registration number NCT05556174.