The goal of this observational study is to ascertain the practice patterns and predictorsin performing lung protective ventilation as per clinical guidelines for adult patientsundergoing non-cardiac surgery in Fraser Health Authority, a large Canadian authority inthe lower mainland of British Columbia, Canada. In particular, the investigators explorechanges before/after the COVID-19 pandemic. The main questions it aims to answer are: - In this population, what is the general compliance rate to lung protective ventilation - In this population, what are the predictors of compliance before/after the COVID-19 pandemic.This is a retrospective study using linked patient data from two databases in the healthregion: the anesthesia informational management system for intraoperative data, and theelectronic medical record for perioperative data.Rationale for study:Breathing problems after surgery affect 5% to 33% of patients and can lead to seriousissues like lung infections, breathing failure, and longer hospital stays, with up to a20% risk of death within 30 days for serious cases. A proven way to reduce these risks islung protective ventilation (LPV), a technique used during surgery where the ventilatordelivers smaller breaths based on clinical guidelines and calculated using a person'sideal body weight, while applying gentle pressure to keep the lungs slightly open. Whilethis approach has been widely adopted in intensive care units over the past 20 years,it's less commonly used in operating rooms, with fewer than half of surgeries using it.Barriers include suboptimal default ventilator settings, patients at extremes of weight,and misunderstandings of LPV among clinicians. During the COVID-19 pandemic, LPV useincreased for patients with COVID-related lung problems, showing improved survival ratesin ICUs. However, it's unclear if this practice carried over to surgical patientsat-large or continued after the pandemic. Most studies on LPV during surgery have beenconducted outside Canada, where healthcare practices and education may differ from withinCanada. To address these gaps, the investigators aim to study LPV use during surgery in alarge Canadian health system, identify factors that influence its use, and examine trendsduring and after the COVID pandemic. This research will help improve patient care bypromoting the use of this effective technique in Canadian operating rooms.