Preoxygenation Method With a Calibrated Leak

Study Overview
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Brief Summary
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During preoxygenation, imperfect seal between the face mask and patient's face can induce an inward air leak decreasing its effectiveness. We assume that noninvasive ventilation could cancel the effect of the leak. This is a prospective study. Healthy volunteers are randomised in cross-over between spontaneous breathing or noninvasive ventilation pressure support preoxygenation in the presence or absence of a calibrated leak on the inspiratory circuit.

Detailed Description
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During preoxygenation, imperfect seal between the face mask and patient's face can induce an inward air leak decreasing its effectiveness. We assume that noninvasive ventilation could cancel the effect of the leak. We planned an experimental study with healthy volunteers (residents in anesthesiology). Healthy volunteers are randomised in cross-over between preoxygenation through spontaeous breathing or noninvasive ventilation pressure support preoxygenation in the presence or absence of a calibrated leak on the inspiratory circuit. The inspiratory fraction of oxygen is 100%. The exhaled gas (oxygen and carbon dioxide) are monitored.The subjects breathed through a mouthpiece (with a nose clip) connected to an anesthetic ventilator. The primary endpoint is the time to achieve end expiratory fraction of oxygene of 90% or more. The secondary endpoint is the proportion of subject with end expiratory fraction of oxygen of 90% or more after a 3 min period (recommended in clinical guidelines).

Official Title
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Effect of Preoxygenation With Spontaneous Breathing or Noninvasive Positive Pressure Ventilation With or Without a Calibrated Leak. An Experimental Study in Healthy Volunteers

Conditions
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Preoxygenation, Non Invasive Ventilation

Intervention / Treatment
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* Procedure: preoxygenation without inward leak
* Procedure: preoxygenation with inward leak


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy volunteers Exclusion Criteria: any pathological condition active tobaco

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: 2 groups : spontaneous breathing and non invasive pressure support ventilation 2 conditions : without inward air leak and with inward air leak
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: spontaneous breathing<br>preoxygenation through spontaneous breathing of 100% oxygen gas flow with or without an inward air leak | Procedure: preoxygenation without inward leak<br>* breathing a 100% inspired oxygen gas flow during 3 to 10 minutes<br>Procedure: preoxygenation with inward leak<br>* breathing a 100% inspired oxygen gas flow during 3 to 10 minutes with an inward air leak made possible through a specific calibrated piece on the inspiratory branch<br>|
| Active Comparator: pressure support ventilation<br>preoxygenation through non invasive pressure support ventilation of 100% oxygen gas flow (inspiratory trigger sensitivity set at -2 l.min-1, the positive inspiratory support set at +6 cmH2O, the PEEP set at +5 cmH2O and the maximal airway pressure was limited at 15 cmH2O.) with or without an inward air leak | Procedure: preoxygenation without inward leak<br>* breathing a 100% inspired oxygen gas flow during 3 to 10 minutes<br>Procedure: preoxygenation with inward leak<br>* breathing a 100% inspired oxygen gas flow during 3 to 10 minutes with an inward air leak made possible through a specific calibrated piece on the inspiratory branch<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| end expiratory fraction of oxygen | end expiratory fraction of oxygen measured in exhaled gas | 10 minutes |