Closed-loop Oxygen Control for High Flow Nasal Therapy

Study Overview
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Brief Summary
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In patients with acute hypoxemic respiratory failure (AHRF), High Flow Nasal Therapy (HFNT) improves oxygenation, tolerance, and decrease work of breathing as compared to standard oxygen therapy by facemask. Current guidelines recommend adjusting oxygen flow rates to keep the oxygen saturation measured by pulse oximetry (SpO2) in the target range and avoid hypoxemia and hyperoxemia. The hypothesis of the study is that closed loop oxygen control increases the time spent within clinically targeted SpO2 ranges and decreases the time spent outside clinical target SpO2 ranges as compared to manual oxygen control in ICU patients treated with HFNT.

Official Title
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Safety and Efficacy of a Closed-loop Oxygen Control for High Flow Nasal Therapy in ICU Patients: a Randomized Cross-over Study (The HILOOP Study)

Conditions
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High Flow Nasal Cannula, Oxygen Therapy, Hypoxemia, Hyperoxemia, Acute Respiratory Failure, Respiratory Insufficiency

Intervention / Treatment
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* Device: Oxygen close-loop
* Device: No intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult (>17yo) patients admitted to the ICU treated with HFNT for at least 8h Requiring FiO2 ≥ 30% to keep SpO2 in the target ranges defined by the clinician Written informed consent signed and dated by the patient or one relative in case that the patient is unable to consent, after full explanation of the study by the investigator and prior to study participation. Exclusion Criteria: Patient with indication for immediate continuous positive airway pressure (CPAP), noninvasive ventilation (NIV), or invasive mechanical ventilation Hemodynamic instability defined as a need of continuous infusion of epinephrine or norepinephrine > 1 mg/h Low quality on the SpO2 measurement using finger and ear sensor (quality index below 60% on the Massimo SpO2 sensor, which is displayed by a red or orange colour bar) Severe acidosis (pH ≤ 7.30) Pregnant woman Patients deemed at high risk for need of mechanical ventilation within the next 8 hours Chronic or acute dyshemoglobinemia: methemoglobin, carbon monoxide (CO) poisoning, sickle cell disease Tracheotomised patient Formalized ethical decision to withhold or withdraw life support Patient under guardianship Patient deprived of liberties Patient included in another interventional research study under consent Patient already enrolled in the present study in a previous episode of acute respiratory failure

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: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Oxygen close-loop<br>Four hours period where the fraction of inspired oxygen delivered will be automatically titrated based on SpO2 values. | Device: Oxygen close-loop<br>* The Automatic FiO2 option provides automated adjustment of the ventilator Oxygen setting to maintain the patient's SpO2 in a defined target range. When using the software option, the user defines the SpO2 target range, as well as the SpO2 emergency limits, and the device adjusts the Oxygen setting to keep the patient's SpO2 in the target range.<br>|
| Active Comparator: Manual FiO2 adjustment<br>Four hours period where the fraction of inspired oxygen delivered will be manually adjusted by the healthcare personnel based on SpO2 values. | Device: No intervention<br>* Manual FiO2 adjustment according to SpO2 values<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of time spent in optimal SpO2 range | The optimal SpO2 range will be defined according to the SpO2 targets determined by the clinician. | 4 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of time spent in sub-optimal SpO2 range | SpO2 values outside the optimal range but still within an acceptable limit (2-3 percent above and below the optimal range) | 4 hours | 
| Percentage of time spent out of range | Above or below the suboptimal limits specified at the begginning of the study | 4 hours | 
| Percentage of time with SpO2 signal available | Time with SpO2 signal available | 4 hours | 
| Mean SpO2/FiO2 | Mean oxygenation value | 4 hours | 
| ROX index | Is a predictor of HFNT success/failure defined as (SpO2/FiO2)/respiratory rate | 4 hours | 
| Percentage of time with SpO2 below 88 and 85 percent | Duration of time with SpO2 <85 percent and <88 percent, respectively | 4 hours | 
| Number of events with SpO2 below 88 and 85 percent | Frequency of SpO2 decreases <85 percent and <88 percent, respectively | 4 hours | 
| Mean FiO2 | Mean fraction of inspired oxygen | 4 hours | 
| Percentage of time with FiO2 below 40 percent and above 60% | Percentage of time that FiO2 is <40 percent and >60 percent, respectively | 4 hours | 
| Number of manual adjustments | Frequency of manual adjustments of FiO2 | 4 hours | 
| Number of alarms | Frequency of alarms | 4 hours | 
| Patient comfort | Comfort score by visual analogic scale (from 0 to 10) | 4 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High flow nasal cannula, Nasal high flow, Oxygen close-loop, Hypoxemia, Hyperoxemia