Efficiency of Preoxygenation in Obese Patients: Pressure Assisted Versus Traditional Method

June 10, 2008 updated by: Maisonneuve-Rosemont Hospital

Efficiency of Preoxygenation in Obese Patients: Evaluation of Traditional Method Versus Pressure Assisted Preoxygenation.

The purpose of this clinical trial is to evaluate whether pre-oxygenation of obese patients with BiPAP 4cm H2O, renders any benefit to the quality of pre-oxygenation measured by the expired oxygen fraction (FeO2) and whether it is as well tolerated as the traditional method of spontaneous breathing for 3 minutes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Traditional pre-oxygenation in obese patients has been proven to allow a time of apnea far reduced when compared with patients closer to their ideal body weight. This effect is attributable to several factors :

  • Reduced FRC
  • Increased closing capacity
  • Diminished tidal volume due to increased resistance of the airway, diminished compliance of the thoracic cage and diminished strength and endurance of respiratory muscles.
  • Increase in atelectasis formation upon induction of general anaesthesia.
  • Increased O2 consumption due to the increased workload of respiratory muscles and to the general increase in metabolism.
  • Increase in true shunt. Studies have demonstrated a reduction in atelectasis formation by application of CPAP during pre-oxygenation and PEEP during anaesthesia. Also, 25º inclination of the patient in the supine position, on the operating table, has demonstrated prolongation of time of apnea in a significant amount. Outside the operating room, PEEP of 5 cmH2O has been demonstrated useful in prolonging time of apnea when used during pre-oxygenation in hypoxic patients requiring tracheal intubation in the intensive care.

Yet, few studies have evaluated BiPAP in the operating room setting as to the effect on FeO2 and to the tolerance by the patients.

Thus, it is our intent to evaluate the efficiency of application of an inspiratory assistance pressure of 4cmH2O and PEEP 4cmH2O during a 3 minutes pre-oxygenation trial as to the level of FeO2 attained, the rate of attainment of FeO2 > 90% and the tolerance by the patient of the procedure, when compared with a 3 minute trial of the traditional method.

For this purpose, consenting, non pre-medicated obese patients scheduled for surgery in the operating ward of our institution will be brought earlier to the operating room, the day of their surgery. In an idle operating room, they will go through two trials of 100% O2 pre-oxygenation lasting 3 minutes each, at an interval of 20 minutes during which the patients will rest in a semi-sitting position, breathing spontaneously at ambient air. The order of the two trials will be randomly assigned between standard pre-oxygenation vs BiPAP pre-oxygenation. Both patients and anesthesia assistants providing the pre-oxygenation will be blinded as to the ongoing trial. Data from the anesthesia machine will be recorded visually to be analysed subsequently by a blinded third party. During each trial, the comfort of the patient on a local 4 point scale will be graded every minute.

At the end of the study period, patients will be returned to the waiting area of the operating ward before the scheduled time of their surgery. The protocol is intended to not interfere with the planned anesthesia technique or the surgery in any way.

Study Type

Interventional

Enrollment (Actual)

30

Phase

  • Not Applicable

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
    • Quebec
      • Montreal, Quebec, Canada, H1T 2M4
        • Maisonneuve-Rosemont Hospital

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

18 years to 75 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • BMI > 30
  • Scheduled for surgery

Exclusion Criteria:

  • Non fasted patient
  • Clinically significant gastro-oesophageal reflux
  • Intestinal occlusion
  • Presence of nasogastric tube
  • Facial hair
  • Claustrophobia

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

  • Primary Purpose: PREVENTION
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: TRIPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: 1
Standard preoxygenation
Procedure: Standard preoxygenation
Spontaneous breathing of 100% oxygen in a facemask for 3 minutes.
ACTIVE_COMPARATOR: 2
BiPAP assisted preoxygenation
Procedure: BiPAP assisted preoxygenation
Spontaneous breathing of 100% oxygen in a facemask with application of an inspiratory pressure of 4cm H2O and a positive end-expiratory pressure of 4cm H2O, for 3 minutes.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
rate of increase of fractional expired oxygen level
Time Frame: every 10 seconds during each 3 minute preoxygenation period
every 10 seconds during each 3 minute preoxygenation period

Secondary Outcome Measures

Outcome Measure
Time Frame
Level of fractional expired oxygen. Patient tolerance. Ease of preoxygenation administration. Presence of secondary effects (gastric reflux, respiratory discomfort, burps)
Time Frame: every minute during each 3 minute preoxygenation trial and at the end of each trial
every minute during each 3 minute preoxygenation trial and at the end of each trial

Collaborators and Investigators

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

Sponsor

Maisonneuve-Rosemont Hospital

Investigators

  • Study Director: Pierre Drolet, MD, FRCPC, Maisonneuve-Rosemont Hospital
  • Principal Investigator: Mihai L Georgescu, MD, resident, Maisonneuve-Rosemont Hospital / Université de Montréal

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

March 1, 2008

Primary Completion (ACTUAL)

May 1, 2008

Study Completion (ACTUAL)

May 1, 2008

Study Registration Dates

First Submitted

May 5, 2008

First Submitted That Met QC Criteria

May 6, 2008

First Posted (ESTIMATE)

May 7, 2008

Study Record Updates

Last Update Posted (ESTIMATE)

June 12, 2008

Last Update Submitted That Met QC Criteria

June 10, 2008

Last Verified

May 1, 2008

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 07122

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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