Impact of a positive end-expiratory pressure strategy on oxygenation, respiratory compliance, and hemodynamics during laparoscopic surgery in non-obese patients: a systematic review and meta-analysis

Background: Higher positive end-expiratory pressure (PEEP) during laparoscopic surgery may increase oxygenation and respiratory compliance. This meta-analysis aimed to compare the impact of different intraoperative PEEP strategies on arterial oxygenation, compliance, and hemodynamics during laparoscopic surgery in non-obese patients. Methods. We searched RCTs in PubMed, Cochrane Library, Web of Science, and Google Scholar from January 2012 to January 2022 comparing the different intraoperative PEEP (Low PEEP (LPEEP): 0 mbar; Moderate PEEP (MPEEP): 5–8 mbar; high PEEP (HPEEP): >8 mbar; individualized PEEP - iPEEP) on arterial oxygenation, respiratory compliance (Cdyn), mean arterial pressure (MAP), and heart rate (HR). We calculated mean differences (MD) with 95% confidence intervals (CI), and predictive intervals (PI) using random-effects models. The Cochrane Bias Risk Assessment Tool was applied. Results. 21 RCTs (n = 1554) met the inclusion criteria. HPEEP vs LPEEP increased PaO 2 (+ 29.38 [16.20; 42.56] mmHg, p < 0.0001) or PaO 2 /FiO 2 (+ 36.7 [+ 2.23; +71.70] mmHg, p = 0.04). HPEEP vs MPEEP increased PaO 2 (+ 22.00 [+ 1.11; +42.88] mmHg, p = 0.04) or PaO 2 /FiO 2 (+ 42.7 [+ 2.74; +82.67] mmHg, p = 0.04). iPEEP vs MPEEP increased PaO 2 /FiO 2 (+ 115.2 [+ 87.21; +143.20] mmHg, p < 0.001). MPEEP vs LPEP, and HPEEP vs MPEEP increased PaO 2 or PaO 2 /FiO 2 significantly with different heterogeneity. HPEEP vs LPEEP increased Cdyn (+ 7.87 [+ 1.49; +14.25] ml/mbar, p = 0.02). MPEEP vs LPEEP, and HPEEP vs MPEEP didn’t impact Cdyn (p = 0.14 and 0.38, respectively). iPEEP vs LPEEP decreased driving pressure (-4.13 [-2.63; -5.63] mbar, p < 0.001). No significant differences in MAP or HR were found between any subgroups. Conclusion. HPEEP and iPEEP during PNP in non-obese patients may improve oxygenation, increase Cdyn without clinically significant changes in MAP and HR. MPEEP could be insufficient to increase respiratory compliance and improve oxygenation. LPEEP could lead to hypoxemia and decreased respiratory compliance. PROSPERO REGISTRATION: CRD42022362379; registered October 09, 2022