Intraoperative Driving Pressure and Postoperative Pulmonary Complications After Abdominal Surgery – A Posthoc Propensity Score–Weighted Cohort Analysis of the LAS VEGAS Study Comparing Open to Closed Surgery

Abstract Background: It is uncertain whether associations between driving pressure (ΔP) during and occurrence of pulmonary complications after abdominal surgery depend on the surgical approach. Our primary objective was to test the time–weighted average ΔP (ΔPTW) association with postoperative pulmonary complications and our secondary objective was to test the association between ΔPTW and intraoperative Adverse Events. Methods: We realized a posthoc retrospective propensity score weighted cohort analysis of the ‘Local ASsessment of Ventilatory management during General Anesthesia for Surgery’ (LAS VEGAS) study including patients undergoing abdominal surgery from the study database including data from 146 hospitals across 29 countries. The primary endpoint was a composite of postoperative pulmonary complications. The secondary endpoint was the occurrence of intraoperative adverse events. Results: The analysis included 1,128 and 906 patients undergoing open or closed abdominal surgery repsectively. Absolute postoperative pulmonary complications rate was 5%. While driving pressure was lower in open abdominal surgery patients, time-weighted driving pressure was not different between groups. The association of ΔPTW with occurrence of postoperative pulmonary complications was significant in both groups, with a higher risk ratio in closed than in open abdominal surgery patients (1.11 [95%CI 1.10 to 1.20], P<0.001 vs. 1.05 [95% CI 1.05 to 1.05; P<0.001; risk difference 0.05: [95%CI 0.04 to 0.06], P<0.001). ΔPTW marginal effect estimation showed increased probability of pulmonary complication in both groups with a steeper increase in closed surgery patients at ΔPTW above 20 cmH2O∙hour-1. The association of ΔPTW with occurrence of intraoperative adverse events was also significant in both groups, with higher odds ratio in closed surgery (1.13 [95%CI 1.12 to 1.14]; P<0.001 vs. 1.07 [95%CI 1.05 to 1.10]; P<0.001; difference 0.05 [95%CI 0.03 to 0.07]; p<0.001). Conclusions: Our results show how driving pressure represents a marker for pulmonary complications and adverse events in abdominal surgery regardless of surgical approach.Trial registration: LAS VEGAS was registered at clinicaltrials.gov (trial identifier NCT01601223).