Cohort Study of Intraoperative Lung Protective Ventilation Trends in a Large Canadian Health Authority

May 28, 2026 updated by: Perseus Missirlis

The goal of this observational study is to ascertain the practice patterns and predictors in performing lung protective ventilation as per clinical guidelines for adult patients undergoing non-cardiac surgery in Fraser Health Authority, a large Canadian authority in the lower mainland of British Columbia, Canada. In particular, the investigators explore changes 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 health region: the anesthesia informational management system for intraoperative data, and the electronic medical record for perioperative data.

Rationale for study:

Breathing problems after surgery affect 5% to 33% of patients and can lead to serious issues like lung infections, breathing failure, and longer hospital stays, with up to a 20% risk of death within 30 days for serious cases. A proven way to reduce these risks is lung protective ventilation (LPV), a technique used during surgery where the ventilator delivers smaller breaths based on clinical guidelines and calculated using a person's ideal body weight, while applying gentle pressure to keep the lungs slightly open. While this 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 use increased for patients with COVID-related lung problems, showing improved survival rates in ICUs. However, it's unclear if this practice carried over to surgical patients at-large or continued after the pandemic. Most studies on LPV during surgery have been conducted outside Canada, where healthcare practices and education may differ from within Canada. To address these gaps, the investigators aim to study LPV use during surgery in a large Canadian health system, identify factors that influence its use, and examine trends during and after the COVID pandemic. This research will help improve patient care by promoting the use of this effective technique in Canadian operating rooms.

Study Overview

Status

Completed

Conditions

Detailed Description

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.

Study Type

Observational

Enrollment (Actual)

28700

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • British Columbia
      • Surrey, British Columbia, Canada, V3T 0H1
        • Fraser Health Authority

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients from January 2014 to December 2023, age above 18, undergoing non-cardiac and non-thoracic surgery for greater than 30 minutes with an endotracheal tube placed. Both inpatients and outpatients are eligible.

Description

Inclusion Criteria:

  • over the age of 18
  • underwent general anesthesia with endotracheal tube placement for a procedure lasting ≥30 minutes.
  • included in both our clinical anesthesia record database and the National Surgical Quality Improvement Program (NSQIP) database, and linkable by usual identifiers (name, date of birth, medical record number, personal health number, date of surgery)

Exclusion Criteria:

  • no endotracheal tube utilized
  • cardiothoracic surgery
  • organ donation surgery
  • organ transplant recipient
  • Hyperthermic intraperitoneal chemotherapy
  • surgical procedure related to an occurrence or complication of prior procedure during the same admission/within 30 days,
  • multiple NSQIP assessed cases within 30 days only for same patient
  • cases in clinical anesthesia record database that are unable to be linked to NSQIP data or vice versa.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Pre-COVID cohort
Before January 2020. The investigators considered before January 2020 as the pre-COVID era, and after June 2020 as the COVID era. The former cutoff was chosen as January 2020 contained the first COVID case in British Columbia, the province containing the study sites. The latter cutoff was chosen as it constitutes three months after March 2020, when the World Health Organization (WHO) announced COVID's pandemic status, and British Columbia announced a state of emergency with the start of isolation policies. The investigators hypothesized that any impact of the COVID pandemic on lung protective ventilation practice patterns would unlikely to have occurred prior COVID's arrival in BC, but would likely be in full swing three months after initiation of widespread social isolation, a very palpable event in society.
2020s cohort
After June 2020. The investigators considered before January 2020 as the pre-COVID era, and after June 2020 as the COVID era. The former cutoff was chosen as January 2020 contained the first COVID case in British Columbia, the province containing the study sites. The latter cutoff was chosen as it constitutes three months after March 2020, when the WHO announced COVID's pandemic status, and British Columbia announced a state of emergency with the start of isolation policies. The investigators hypothesized that any impact of the COVID pandemic on lung protective ventilation practice patterns would unlikely to have occurred prior COVID's arrival in BC, but would likely be in full swing three months after initiation of widespread social isolation, a very palpable event in society.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Lung protective ventilation compliance
Time Frame: For patients not ventilated preoperatively: from insertion to removal of endotracheal tube (or until end of case if tube not removed). For already ventilated patients: from start to end of operation.
Compliance with ventilation guidelines is defined as meeting two criteria. The first is that their average tidal volume is 6-8 mL/kg ideal body weight and the second is that the average positive end expiratory pressure is at least 5 cm H2O. Patients ventilated according to one or neither of the above criteria will not be considered to have been ventilated according to established guidelines.
For patients not ventilated preoperatively: from insertion to removal of endotracheal tube (or until end of case if tube not removed). For already ventilated patients: from start to end of operation.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Perseus Missirlis

Collaborators

University of British Columbia

Investigators

  • Principal Investigator: Perseus Missirlis, MD, MSc, University of British Columbia

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2014

Primary Completion (Actual)

December 31, 2023

Study Completion (Actual)

December 31, 2023

Study Registration Dates

First Submitted

January 14, 2025

First Submitted That Met QC Criteria

February 8, 2025

First Posted (Actual)

February 11, 2025

Study Record Updates

Last Update Posted (Actual)

June 1, 2026

Last Update Submitted That Met QC Criteria

May 28, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FHREB 2020-083
  • H20-01683 (Other Identifier: University of British Columbia)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual patient data (IPD) is obtained from medical record registries at Fraser Health Authority. While IPD used in this study will not be shared, these data (and similar data at other time frames) are freely available to investigators of subsequent proposed studies, in collaboration with an investigator at Fraser Health Authority, through the usual data access application mandated by Fraser Health Authority.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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