Effects of High-flow Oxygen Therapy and Non-invasive Ventilation on Lung Volumes and on Upper Airway

Study Overview
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Brief Summary
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Respiratory failure is the most frequent organ failure and cause for admission in the Intensive Care Unit (ICU) . It is a severe complication with an ICU mortality ranged from 31% to 33%. Symptomatic treatment of hypoxemic respiratory failure is a controversial topic with different options: 1) standard oxygen therapy, 2) high flow nasal cannula oxygen therapy (HFNC) and 3) non-invasive ventilation (NIV). The aim of the study is to compare HFNC versus NIV ventilation using CT scan. The hypothesis of this study is that in hypoxemic critically ill patients, the increase of lung volumes with NIV would be significantly higher than the increase of lung volumes with HFNC.

Official Title
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Effects of High-flow Oxygen Therapy and Non-invasive Ventilation on Lung Volumes and on Upper Airway in Hypoxemic Critical Care Patients: a Physiological Randomized Controlled Trial

Conditions
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Respiratory Failure

Intervention / Treatment
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* Procedure: HFNC
* Procedure: NIV


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient with hypoxemia at any time of ICU stay defined as follow: standard oxygen therapy flow ≥ 3L/min to maintain a pulsed oxygen saturation ≥ 95% Adult (age ≥ 18 years) (2) A CT scan prescribed by the physician in charge of the patient as part of the exploration of the patient's pathology and not as part of a dedicated prescription for the study. Exclusion Criteria: NIV contraindication (need for immediate endotracheal intubation and mechanical ventilation; hemodynamic instability defined by systolic blood pressure < 90 mmHg or mean blood pressure < 65 mmHg, use of vasopressors; Glasgow Coma Scale score of 12 points or less) History of recent facial trauma not compatible with the use of nasal cannulas Pregnancy Refusal of study participation protected person Patient not affiliated to the social security system or not benefiting from such a system Lack of signed informed consent

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: HFNC (Hight-flow oxygen therapy)<br>In the HFNC group, patients will receive HFNC oxygen therapy for 20 minutes. Oxygen will be passed through a heated humidifier and continuously delivered through medium or large nasal cannulas (OptiflowTM, Fisher and Paykel Healthcare) depending on patient anatomy, with a gas flow of 50 litres per minute and the FiO2 will be adjusted to maintain a SpO2 between 95% and 98%. | Procedure: HFNC<br>* In the HFNC group, patients will receive HFNC oxygen therapy for 20 minutes.<br>|
| Active Comparator: Non-invasive ventilation (NIV)<br>In the NIV Group, patients will receive NIV for 20 minutes delivered with a naso-buccal or face mask according to the patient's tolerance. The pressure-support level will be adjusted with the aim of an expired tidal volume of 6 to 8 ml per kilogram of predicted body weight, with a positive end-expiratory pressure (PEEP) of 5 cmH2O. The FiO2 will be adjusted to maintain a SpO2 between 95% and 98%. | Procedure: NIV<br>* Patients will receive NIV for 20 minutes delivered with a naso-buccal or face mask according to the patient's tolerance.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variation in poorly aerated lung volume | The poorly aerated volume will be measured by CT scan | the day of inclusion | 
| Variation in non-aereted lung volume | The non-aereted volume will be measured by CT scan | the day of inclusion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variation in cross-sectional upper airway area | The variation will be measured by CT-scan in mm | the day of inclusion | 
| Variation in normally aerated lung volume | The normally aerated lung volume will be measured by CT scan | the day of inclusion | 
| Variation in Positive End Expiratory Pressure (PEEP) |  | the day of inclusion | 
| Variation in Total lung volume | The total lung volume will be measured by CT-scan | the day of inclusion | 
| Variation in O2 gas exchange | Change in PaO2 in mmHg | the day of inclusion | 
| Variation in CO2 gas exchange | Change in PaO2 in mmHg | the day of inclusion | 
| Variation in respiratory rate | Respiratory rate is the number of cycles per minute | the day of inclusion | 
| Variation in cardiac output (Qc) | the cardiac output is in L/min | the day of inclusion | 
| Variation in patient comfort | Patient comfort through a numeric rating scale (NRS) from 0 (no discomfort) to 10 (maximum imaginable discomfort) | the day of inclusion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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intensive care, non-invasive ventilation, high-flow nasal oxygen therapy, hypoxemic respiratory failure, upper airway