Recruitment maneuvers to reduce pulmonary atelectasis after cardiac surgery: A meta-analysis of randomized trials

Abstract Background Pulmonary atelectasis is a common postoperative complication that may lead to intrapulmonary shunt, refractory hypoxemia, and respiratory distress. Recruitment maneuvers may relieve pulmonary atelectasis in patients undergoing cardiac surgery. We conducted a meta-analysis of randomized controlled trials to evaluate the effectiveness of recruitment maneuvers in these patients. Methods We conducted a search in PubMed, Embase, Cochrane Library, and the ClinicalTrials.gov registry for trials published before March 2020. Individual effect sizes were standardized, and a meta-analysis was performed to calculate a pooled effect size by using random-effects models. Pulmonary atelectasis was assessed postoperatively. Secondary outcomes included hypoxic events, arterial oxygen tension (Pao2)/inspired oxygen fraction (Fio2) ratio, cardiac index, mean arterial pressure, and postoperative complications including pneumothorax and pneumonia. Results We reviewed 16 trials involving 1455 patients. Patients receiving recruitment maneuvers had a reduced incidence of pulmonary atelectasis (group with recruited pressure >40 cmH2O: risk ratio [RR], 0.20; 95% confidence interval [CI], 0.07-0.57; group with recruited pressure Conclusions Recruitment maneuvers may reduce postoperative pulmonary atelectasis, hypoxic events, and pneumonia and improve Pao2/Fio2 ratios without hemodynamic disturbance in patients undergoing cardiac surgery.