A Physiological Study to Assess Awake Prone Positioning and Respiratory Support in Healthy Volunteers

Study Overview
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Brief Summary
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Awake prone positioning (APP) has been proven to reduce the intubation rate for patients with COVID-19-induced hypoxemic respiratory failure. Our recent meta-analysis found APP was only effective for patients who were treated by high-flow nasal cannula (HFNC), not for patients using conventional oxygen therapy (COT).In a recent multicenter RCT, Perkins and colleagues reported that continuous positive airway pressure (CPAP) was superior to HFNC and conventional oxygen therapy in reducing intubation rate. Thus, it is essential to evaluate the physiological mechanism of APP under different respiratory supports, such as COT, HFNC, or CPAP. We hypothesize that HFNC or CPAP is more effective when combined with APP than COT combined with APP. Electrical impedance tomography (EIT imaging) has been broadly utilized to assess patient ventilation homogeneity and respiratory volume monitor (RVM) has been used to evaluate patient's tidal volumes breath-by-breath. In this study, 20 healthy volunteers will use different respiratory support devices (HFNC, CPAP, and COT) in different settings and their combinations withAPP in a random sequence, assessed by EIT and RVM.

Detailed Description
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Awake prone positioning (APP) has been proven to reduce the intubation rate for patients with COVID-19-induced hypoxemic respiratory failure. Our recent meta-analysis found APP was only effective for patients who were treated by high-flow nasal cannula (HFNC), not for patients using conventional oxygen therapy (COT).In a recent multicenter RCT, Perkins and colleagues reported that continuous positive airway pressure (CPAP) was superior to HFNC and conventional oxygen therapy in reducing intubation rate. Thus, it is essential to evaluate the physiological mechanism of APP under different respiratory supports, such as COT, HFNC, or CPAP.

Official Title
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A Physiological Study to Assess the Effects of Awake Prone Positioning in Healthy Volunteers Under Different Respiratory Support: A Randomized Crossover Study

Conditions
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Healthy

Intervention / Treatment
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* Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: healthy adults aged between 21 to 65 years Exclusion Criteria: Tested COVID positive within 21 days, or has any of the following symptoms in the last 21 days: sore throat, cough, chills, body aches for unknown reasons, shortness of breath for unknown reasons, loss of smell, loss of taste, fever at or greater than 100 degrees Fahrenheit. Currently have the following symptoms: sore throat, fever, coughing, shortness of breath, loss of smell or taste Non-English speaking Has any of the following diseases: asthma, chronic obstructive pulmonary disease, Uncontrolled Diabetes, hypertension, or untreated thyroid disease and spinal cord injury. Claustrophobia Pregnancy Pacemaker (EIT contraindication) face or chest skin injury that could not use a facemask or the electrode belt could not tolerate prone positioning for one hour

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 65 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: Other
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: awake prone positioning with room air<br>Participants will stay in the prone position | Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)<br>* in this group, healthy subjects will stay in prone position for 20 mins with respiratory support of high-flow nasal cannula or CPAP<br>|
| Experimental: awake prone positioning with high-flow nasal cannula<br>Participants will stay in the prone position and breathe with high-flow nasal cannula | Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)<br>* in this group, healthy subjects will stay in prone position for 20 mins with respiratory support of high-flow nasal cannula or CPAP<br>|
| Experimental: awake prone positioning with continuous positive airway pressure<br>Participants will stay in the prone position and breathe with continuous positive airway pressure via face mask | Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)<br>* in this group, healthy subjects will stay in prone position for 20 mins with respiratory support of high-flow nasal cannula or CPAP<br>|
| No Intervention: supine position with room air<br>Participants will stay in the supine position | |
| Active Comparator: supine position with high-flow nasal cannula<br>Participants will stay in the supine position and breathe with high-flow nasal cannula | Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)<br>* in this group, healthy subjects will stay in prone position for 20 mins with respiratory support of high-flow nasal cannula or CPAP<br>|
| Active Comparator: supine position with continuous positive airway pressure<br>Participants will stay in the supine position and breathe with continuous positive airway pressure via face mask | Other: awake prone positioning with advanced respiratory support (high-flow nasal cannula or continuous positive airway pressure)<br>* in this group, healthy subjects will stay in prone position for 20 mins with respiratory support of high-flow nasal cannula or CPAP<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ventilation distribution assessed by EIT | Regional ventilation assessed by regional tidal impedance variations relative to global tidal impedance variation (ΔzROI/Δzglobal) obtained by electrical impedance tomography (EIT) | 20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| tidal volume | the gas volume during tidal breathing | 20 minutes | 
| respiratory rates | breathing frequency during tidal breathing | 20 minutes | 
| comfort | subject's comfort which will be assessed by a 1-10 scale | 20 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Prone positioning, high-flow nasal cannula, continuous positive airway pressure