This observational study aims to elucidate the patterns and predictors of intraoperative lung protective ventilation (LPV) in adult patients undergoing non-cardiac surgery at Fraser Health Authority, a large Canadian health authority on the west coast of Canada, between 2014-2023. It also assesses the impact of pre-COVID vs. 2020s era on LPV compliance, and interactions of predictors with pre-COVID vs. 2020s era. LPV is defined as both 1) tidal volume of 6-8mL/kg ideal body weight and 2) positive end-expiratory pressure of 5 cmH2O or more. Intraoperative data will be derived from the intraoperative anesthesia information management system, and the perioperative data from the regional electronic medical record. The investigators will use a predictive logistic regression model to ascertain statistically significant predictors to LPV. Hypothesized predictors of LPV compliance based on literature and expert opinion will be considered for inclusion in the model. Pre-COVID and 2020s data will be compared, and interactions with predictors will be explored. As a secondary analysis, a Shewhart chart will be used to elucidate any special cause variation in LPV compliance introduced by the COVID pandemic. For details of descriptive analyses, model derivation, and Shewhart chart methodology, please refer to study protocol.
