Background: Lung-protective ventilation strategies are recommended for patients undergoing mechanical ventilation. However, there are currently no guidelines to follow regarding recruitment maneuvers (RMs). We attempted to identify the effects of RMs on patients undergoing laparoscopic abdominal surgery. Methods: We searched for randomized controlled trials (RCTs) in PubMed, the Cochrane Library databases, Embase, Web of Science and the ClinicalTrials.gov registry for trials published up to December 2021. The primary outcome was postoperative pulmonary complications (PPCs). The secondary outcomes consisted of the static lung compliance, driving pressure (DP), intraoperative oxygenation index (OI), OI in the post-anesthesia care unit (PACU), mean arterial pressure (MAP) and heart rate (HR). Seventeen RCTs with a total of 3480 patients were examined. Results: Patients who received RMs showed a considerable reduction in PPCs (risk ratio (RR) = 0.70; 95% confidence interval (CI): 0.62 to 0.79; p < 0.01), lower DP (weighted mean difference (WMD) = −3.96; 95% CI: −5.97 to −1.95; p < 0.01), elevated static lung compliance (WMD = 10.42; 95% CI: 6.13 to 14.71; p < 0.01) and improved OI (intraoperative: WMD = 53.54; 95% CI: 21.77 to 85.31; p < 0.01; PACU: WMD = 59.40; 95% CI: 39.10 to 79.69; p < 0.01) without substantial changes in MAP (WMD = −0.16; 95% CI −1.35 to 1.03; p > 0.05) and HR (WMD = −1.10; 95% CI: −2.29 to 0.10; p > 0.05). Conclusions: Recruitment maneuvers reduce postoperative pulmonary complications and improve respiratory mechanics and oxygenation in patients undergoing laparoscopic abdominal surgery. More data are needed to elucidate the effect of recruitment maneuver on the circulatory system.

Background Sepsis-induced acute lung injury (ALI) is one of the leading causes of death among critically ill patients. It is reported that Protectin DX (PDX), a kind of special pro-resolving mediator (SPM), has been recently discovered to contribute to the improvement of inflammatory diseases. However, its effect and mechanism on regulating ALI are still unknown. Methods We used C57BL/6J mice to construct ALI model via cecal ligation and puncture (CLP). Mice were injected intraperitoneally with saline or PDX one hour after modelling. We performed in-vitro experiments to explore the relationship between PDX and neutrophils. The neutrophils were isolated from healthy volunteers. They were treated with lipopolysaccharide (LPS) and different concentrations of PDX within one hour. Results We found that PDX can increase the survival rate of septic mice in eight days through the survival experiment, probably due to that PDX improved oxygenation of septic mice and alleviated sepsis-induced pathological lung injury and inflammation. Immunohistochemical and immunofluorescence experiments showed that PDX could effectively reduce the number of neutrophils in the lungs of septic mice. PDX reduced pro-inflammatory cytokines while attenuating sepsis-induced neutrophil activation. Moreover, western blotting results showed that PDX decreased the expression of MAPK (p38, ERK), NF-κB and p47phox-ser345 in lung tissue and neutrophils cultured in vitro. Conclusion Our experiments suggested that PDX can increase survival rate and reduce sepsis-induced ALI by inhibiting neutrophils activation via MAPK/NF-κB/p47phox-ser345 signaling pathway.