An interventional study of High flow oxygen through nasal cannula and face mask and standard oxygen therapy through non-rebreather face mask, and measurement of oxygen and carbon dioxide fraction in the hypopharynx in Healthy Volunteers, sponsored by I.M. Sechenov First Moscow State Medical University. Completed at 1 site in Russia. Open to participants aged 18 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-25.
Sponsored by I.M. Sechenov First Moscow State Medical University · Not applicable, Interventional, and Other
The COVID-19 pandemic has become a huge global problem, affecting all spheres of human life, resulting in enormous social, economic consequences and human tragedies. With very decent results of treatment of patients of average severity in the conditions of bed units, the results of treatment of the most severe category - patients of intensive care units who required tracheal intubation remain extremely unsatisfactory. According to different data, mortality in this category of patients reaches 80-90%. However, observational, randomized studies and their meta-analyses have shown high efficiency of high-flow oxygen therapy through nasal cannulas, reaching 50-60%. Some pilot bench studies (on manikins) have shown the advantages of high-flow oxygen therapy over standard oxygen therapy in reducing anatomical dead space and preserving a given inspiratory fraction of oxygen in the laryngeal pharynx of the manikin, but the actual state of the laryngeal pharyngeal gas composition was not studied. Some patients breathe through open mouth that decreases the efficacy oh high flow oxygen through nasal cannula. The aim of the study is to measure the inspiratory (FiO2) and expiratory (FeO2) oxygen fractions and the inspiratory and expiratory carbon dioxide fractions (FiCO2 and FeCO2, respectively) in the hypopharynx of healthy volunteers during high-flow oxygen therapy through nasal cannula and face mask, and during standard oxygen therapy through non-rebreather face mask under different physiological conditions.
Randomized controlled trials showed reduction of tracheal intubation in high- flow oxygen therapy through nasal cannula group in patients with acute respiratory failure as compared to standard oxygen therapy and noninvasive ventilation before Coronavirus disease-19 (COVID-19) pandemic.
The World Health Organization (WHO) declared the outbreak a pandemic of COVID-19 on March 11th, 2020. Since then observational, randomized studies and their meta-analyses have shown the high effectiveness of high-flow oxygen therapy through nasal cannulas (HFNC), reaching 50-60% in acute hypoxemic respiratory failure.
Bench studies showed the advantages of HFNC compared with standard oxygen therapy, consisting in reducing the anatomical dead space and maintaining a given inspiratory oxygen fraction in the hypopharynx of the mannequin, but the actual state of the gas composition of the hypopharynx during HFNC was not studied. Some patients breathe through open mouth that decreases the efficacy oh high flow oxygen through nasal cannula.
The aim of the study is to measure the inspiratory (FiO2) and expiratory (FeO2) oxygen fractions and the inspiratory and expiratory carbon dioxide fractions (FiCO2 and FeCO2, respectively) in the hypopharynx of healthy volunteers during high-flow oxygen therapy through nasal cannula and face mask, and during standard oxygen therapy through non-rebreather face mask under different physiological conditions.
I.M. Sechenov First Moscow State Medical University is the lead sponsor of 133 studies on the registry; 27 are open to participants now.
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Exclusion Criteria:
High flow oxygen through nasal cannula and face mask and standard oxygen therapy through non-rebreather face mask, and measurement of oxygen and carbon dioxide fraction in the hypopharynx High flow oxygen through nasal cannula and face mask, and standard oxygen therapy through non-rebreather face mask, and measurement of oxygen and carbon dioxide fraction in the hypopharynx of healthy volunteers in different physiological conditions
Device: High flow oxygen through nasal cannula and face mask and standard oxygen therapy through non-rebreather face mask, and measurement of oxygen and carbon dioxide fraction in the hypopharynx
High flow oxygen through nasal cannula and face mask, and standard oxygen therapy through non-rebreather face mask, and measurement of oxygen and carbon dioxide fraction in the hypopharynx of healthy volunteers in different physiological conditions
Inspiratory oxygen fraction (FiO2) in the hypopharynx
Inspiratory oxygen fraction (FiO2) in the hypopharynx during high flow oxygen therapy through nasal cannula and face mask, and standard oxygen therapy through non-rebreather face mask different physiological conditions
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Expiratory oxygen fraction (FeO2) in the hypopharynx
Expiratory oxygen fraction (FeO2) in the hypopharynx during high flow oxygen therapy through nasal cannula and face mask, and standard oxygen therapy through non-rebreather face mask different physiological conditions
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Expiratory fraction of carbon dioxide (FeCO2) in the hypopharynx
Expiratory fraction of carbon dioxide (FeCO2) in the hypopharynx during high flow oxygen therapy through nasal cannula and face mask, and standard oxygen therapy through non-rebreather face mask different physiological conditions
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Respiratory rate (RR)
Respiratory rate (RR)
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Peripheral oxygen saturation (SpO2)
Peripheral oxygen saturation (SpO2) during different physiological conditions
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
The ratio of oxygen saturation by pulse oximetry/inspiratory oxygen fraction to respiratory rate (ROX-index)
The ratio of oxygen saturation by pulse oximetry/inspiratory oxygen fraction to respiratory rate (ROX-index) during different physiological conditions
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Comfort
Visual-analog scale (VAS) for comfort evaluation (from 1 to 10, 1-full comfort, 10-full comfort)
Time frame: 5 minutes after the start of each combination of breathing pattern, device type, fraction of inspired oxygen and preset flow
Plan to share: Yes — All data will be shared upon reasonable request
Supporting information: Study protocol, Icf, Csr
This study is completed, as verified in May 2025. You cannot join it, but the record below documents what was studied.
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I.M. Sechenov First Moscow State Medical University