Effect of ultrasound-guided recruitment maneuver on atelectasis: a systematic review and meta-analysis of randomized controlled trials

To summarize the existing evidence on the effects of ultrasound-guided recruitment maneuver (RM) during perioperative period on atelectasis, oxygenation and other clinical outcomes in adult patients undergoing abdominal surgery. In this systematic review and meta-analysis, PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, and WanFang databases were searched from inception to May 2023 for relevant randomized controlled trials (RCTs) comparing the perioperative use of ultrasound-guided RM with a control group in adult patients undergoing abdominal surgery. The primary outcome was the incidence of early postoperative atelectasis (within 24 h after surgery). A total of 12 RCTs with 895 patients were included. The ultrasound-guided RM significantly reduced the incidence of postoperative atelectasis (RR [risk ratio]: 0.44, 95% CI [confidence interval]: 0.34 to 0.57, P < 0.001), with a median fragility index of 4. Prespecified subgroup analyses demonstrated the consistent findings. Additionally, ultrasound-guided RM could decrease postoperative lung ultrasound score (MD [mean difference]: − 3.02, 95% CI: − 3.98 to − 2.06, P < 0.001), reduce the incidence of postoperative hypoxemia (RR: 0.32, 95% CI: 0.18 to 0.56, P < 0.001), improve postoperative oxygenation index (MD: 45.23 mmHg, 95% CI: 26.54 to 63.92 mmHg, P < 0.001), and shorten post-anesthesia care unit (MD: − 1.89 min, 95% CI: − 3.14 to − 0.63 min, P = 0.003) and hospital length of stay (MD: − 0.17 days, 95% CI: − 0.30 to − 0.03 days, P = 0.02). However, there was no significant difference in the incidence of atelectasis at the end of surgery between two groups (RR: 0.99, 95% CI: 0.86 to 1.14, P = 0.89). The use of ultrasound-guided RM perioperatively reduced the risk of atelectasis and improve oxygenation after abdominal surgery. Strategies to reduce the development of perioperative atelectasis are presented to highlight areas for future research.