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NCT Number: NCT06305273

Effectiveness of Two Different Body Positions During Facemask Ventilation in Obese Patients

It is important to provide enough oxygen to the patients who are asleep during surgery. One way to do this is by using a mask placed over the face to help them breathe. When it becomes difficult getting enough oxygen into the patient's body using the mask, it's called difficult mask ventilation. There can be different reasons for this, and having a higher BMI is one of them. Body physique is assessed by Body Mass Index (BMI). This calculation gives an indication of a person's weight relative to their height.

There is some evidence in the research literature to suggest that when the patient is positioned in a way that helps their airway, like using a device to lift their head and torso 25 degrees , it might help the process of getting enough oxygen work better. The study aims to determine if patients with high BMI can breathe better using a face mask while they are in a head elevated position compared to lying flat on their back.

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Mount Sinai Hospital

Toronto, Ontario, M5G 1X5, Canada

Location status: Recruiting

Location contact

Dr. Fabricio B Zasso, MD, MHSc, MBA

CONTACT

[email protected]

416-586-5270

About this study

Facemask ventilation is an important technique applied by anesthesiologists after induction of general anesthesia and before tracheal intubation. It is also used as a rescue maneuver in situations where a patient's consciousness is compromised affecting oxygenation. Obesity is well known to be one of the difficult predictors for facemask ventilation. In fact, the occurrence of difficult facemask ventilation is more frequent in obese patients than non obese. One of the maneuvers described to optimize the effectiveness of facemask ventilation in the general population is positioning the patient in a 25 degree head elevated position. A previous study has demonstrated improvement in facemask ventilation in obese patients with BMI from 30 to 40 kg/m2 in the head elevated position, compared to supine. However, it is not yet determined if this is applicable to patients with a BMI above 40 kg/m2. Adult obese patients with BMI of at least 40 kg/m2 will be randomized to be ventilated after induction of general anesthesia via a face mask while in one of the positions: supine or head elevated, while the volume of air that enters and exits the lungs is measured. Participants will then be changed to the second position, ventilated in the same manner and measures obtained again.

Do patients with class 3 obesity positioned in the head elevated position can be better ventilated with a face mask and positive pressure, compared to the supine position?

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • BMI > 40 kg/m2
  • age > 18 years
  • scheduled for elective surgery under general anesthesia
  • have the ability to comprehend the rationale for the study and provide consent

Exclusion criteria

  • pregnancy,
  • risk of aspiration of gastric content
  • patients using glucagon-like peptide(GLP)-1 agonists
  • emergency cases
  • upper airway disease or airway anatomical abnormalities
  • presence of major cardiovascular, respiratory, or cerebral vascular disease
  • if the provider anesthesiologist indicates an awake technique to secure the airway

Treatment and study plan

Head position for face mask ventilation during induction supine

Other

Participant to be ventilated starting 2 minutes after induction of general anesthesia via a face mask while in supine position. Participants will be crossed over to the head elevated position after the first measurement is obtained.

Head position for face mask ventilation during induction head elevated

Other

Participant to be ventilated starting 2 minutes after induction of general anesthesia via a face mask while in head elevated position. Participants will be crossed over to the supine position after the first measurement is obtained.

Primary outcomes

  1. Average tidal volume

    Time frame: During induction.

    The primary outcome for this trial is the average tidal volume in 10 ventilations in each position, flat or head elevated.

Secondary outcomes

  1. Predictors for difficult mask ventilation like BMI

    Time frame: During induction

    Secondary outcome will be: the incidence and correlation of other predictors for difficult mask ventilation like BMI.

  2. Predictors for difficult mask ventilation like presence of beard

    Time frame: During induction

    Secondary outcomes will be: the incidence and correlation of other predictors for difficult mask ventilation like, presence of a beard.

  3. Predictors for difficult mask ventilation like Mallampati classification III or IV

    Time frame: During induction

    Secondary outcomes will be: the incidence and correlation of other predictors for difficult mask ventilation like Mallampati classification III or IV.

  4. Predictors for difficult mask ventilation like age of 57 yo or older.

    Time frame: During induction

    Secondary outcomes will be: the incidence and correlation of other predictors for difficult mask ventilation like, age of 57 yo or older.

  5. Predictors for difficult mask ventilation like severely limited mandibular protrusion

    Time frame: During induction

    Secondary outcomes will be: the incidence and correlation of other predictors for difficult mask ventilation like severely limited mandibular protrusion.

  6. Predictors for difficult mask ventilation like history of snoring.

    Time frame: During induction

    Secondary outcomes will be: the incidence and correlation of other predictors for difficult mask ventilation like history of snoring.

  7. Oropharyngeal airway

    Time frame: During induction

    Incidence of use of an oropharyngeal airway during the protocol.

  8. Insufficient mask ventilation

    Time frame: During induction.

    Incidence of insufficient mask ventilation (defined as tidal volume (Vt) < 4 ml/kg IBW), or failed facemask ventilation defined as absence of End-tidal carbon dioxide(EtCO2) after 3 consecutive ventilations.

Study contacts

Contact information is provided by the study sponsor or research team.

Fabricio Zasso, MD

CONTACT

[email protected]

416-586-4800

Sponsors and collaborators

Lead sponsor

Mount Sinai Hospital, Canada

Other

Registry information

Official study title

Effectiveness of Two Different Body Positions During Facemask Ventilation in Class 3 Obesity Patients: a Randomized Crossover Trial

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Mar 12, 2024
Registry last updated
Jun 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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