High-Flow Nasal Cannula (HFNC) Preoxygenation in Obese Patients Undergoing General Anesthesia

Study Overview
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Brief Summary
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This study aims to evaluate the effectiveness of the High Flow Nasal Cannula (HFNC) for the preoxygenation of obese patients undergoing a general anesthesia. The HFNC interface is compared to a standard anesthesia FaceMask (FM) preoxygenation with Continuous Positive Airway Pressure (CPAP), the current gold standard procedure for obese induction. The interest of HFNC preoxygenation is to increase the safe apnea time before critical arterial desaturation, useful in the management of difficult airways, especially in subjects with reduced respiratory reserves such as the obese.

Official Title
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Effectiveness of High-Flow Nasal Cannula (HFNC) Preoxygenation in Obese Patients Undergoing General Anesthesia: A Randomised Controlled Trial

Conditions
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Obesity, Preoxygenation, Anesthesia

Intervention / Treatment
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* Device: High Flow Nasal Cannula (HFNC)
* Device: Standard anesthesia FaceMask (FM)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Surgery with the need for general anesthesia with muscle relaxation ASA (American Society of Anesthesiologists) physical status score II-III BMI > 35 Exclusion Criteria: Severe respiratory disease (acute respiratory failure, Chronic obstructive pulmonary disease COPD, parenchymal pneumopathies,...) Severe nasal pathology (malformation, stenosis) Criteria or previous difficult intubation BMI > 50 Chest circumference > 150cm Implanted electronic device (pacemaker, neurostimulator, ...) Pregnancy

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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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HFNC - High Flow Nasal Cannula<br>Participants are preoxygenated by High Flow Nasal Cannula (HFNC) OptiFlow. | Device: High Flow Nasal Cannula (HFNC)<br>* Preoxygenation trough High Flow Nasal Cannula (HFNC) at 100% FiO2, 50 liters/min and closed mouth. After Rapid Sequence Induction (RSI), maintenance of apnea with HFNC at 100% FiO2, 70 liters/min and jaw thrust. At time of peripheral oxygen saturations (SpO2) decreases by 2% or after 10 minutes of apnea, the participant is intubated.<br>* Other names: OptiFlow;|
| Active Comparator: FM - FaceMask<br>Participants are preoxygenated by standard anesthesia FaceMask. | Device: Standard anesthesia FaceMask (FM)<br>* Preoxygenation trough standard anesthesia FaceMask (FM) at 100% FiO2, 12 liters/min, CPAP 7 cmH2O. After Rapid Sequence Induction (RSI), maintenance of apnea without mask. At time of peripheral oxygen saturations (SpO2) decreases by 2% or after 10 minutes of apnea, the participant is intubated.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Functional Residual Capacity (FRC) variation | The difference of FRC, estimated by lung Electrical Impedance Tomography (EIT), during general anesthesia induction (from a base period to the mechanical ventilation). | 20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time of safe apnea | The time (seconds) of apnea following preoxygenation and muscle relaxation before to peripheral oxygen saturations (SpO2) decreases by 2%, or the apnea time reaches 600 seconds. | 20 minutes | 
| Lowest SpO2 | The lowest SpO2 (%) during general anesthesia induction (from a base period to the mechanical ventilation). | 20 minutes | 
| Preoxygenation Comfort | The subjective comfort of the patient during the preoxygenation, expressed with a 0-5 scale at Post Anesthesia Care Unit (PACU) discharge. | 6 hours |