Impact of a positive end-expiratory pressure on oxygenation, respiratory compliance, and hemodynamics in obese patients undergoing laparoscopic surgery in reverse Trendelenburg position: a systematic review and meta-analysis of randomized controlled trials.

Abstract

<h4>Background</h4>High and individual positive end-expiratory pressure (PEEP) during laparoscopic surgery may improve oxygenation and respiratory mechanics.<h4>Methods</h4>We searched RCTs in PubMed, Cochrane Library, Web of Science, and Google Scholar from from from January 2000 to December 2023 comparing the different intraoperative PEEP (low PEEP (LPEEP): 0-5 mbar; moderate PEEP (MPEEP): 6-9 mbar; high PEEP (HPEEP): >=10 mbar; individualized PEEP (iPEEP): PEEP set by special physiological technique) on arterial oxygenation, respiratory compliance (Cdyn) or driving pressure, mean arterial pressure (MAP), and heart rate (HR) in patients during laparoscopic surgery in reverse Trendelenburg position. 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.<h4>Results</h4>8 RCTs (n = 425) met the inclusion criteria. HPEEP vs. LPEEP increased PaO₂/FiO₂ (+ 129.93 [+ 75.20; +184.65] mmHg, p < 0.0001) with high variation of true effect (Chi² 34.92, p < 0.0001; I² 89%). iPEEP vs. LPEEP also increased PaO₂/FiO₂ + 130.23 [+ 57.18; +203.27] mmHg, p = 0.0005) with high variation of true effect (Chi² 26.95, p < 0.0001; I² 93%). HPEEP vs. LPEEP increased Cdyn (+ 15.06 [5.47; +24.65] ml/mbar, p = 0.002) with high variation of true effect (Chi² 93.16, p < 0.0001; I² 96%). iPEEP vs. LPEEP increased Cdyn (+ 22.46 [+ 8.56; +36.35] ml/mbar, p = 0.002) with high variability of the true effect (Chi² 53.92, p < 0.0001; I² 96%). HPEEP group had higher MAP as compared to LPEEP) + 4.36 [+ 0.36;+8.36], p = 0.03), variability of the true effect was nonsignificant. HR did nit differ between all comparisons.<h4>Conclusion</h4>In patients with obesity undergoing surgery in the reverse Trendelenburg position HPEEP and iPEEP may improve oxygenation, decrease driving pressure, and increase dynamic compliance compared to LPEEP with high variation of true effect without relevant hemodynamic compromise. Data with MPEEP comparisons are inconclusive.<h4>Prospero registration</h4>CRD42023488971; registered December 14, 2023.