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Observational, randomized studies and their meta-analyses have shown the high effectiveness of high-flow oxygen therapy through nasal cannulas, reaching 50-60% in acute hypoxemic respiratory failure. Some bench studies showed the advantages of high-flow oxygen therapy 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 was not studied. The study aim is measurement of the inspiratory (FiO2) and expiratory (FeO2) fractions of oxygen, as well as the inspiratory (FiСO2) and expiratory (FeСO2) fractions of carbon dioxide in the hypopharynx of healthy volunteers during high-flow oxygen therapy through nasal cannulas in different physiological conditions.
Randomized controlled trials showed reduction of tracheal intubation in high-flow oxygen therapy through nasal cannulas 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.
The study aim is measurement of the inspiratory (FiO2) and expiratory (FeO2) fractions of oxygen, as well as the inspiratory (FiСO2) and expiratory (FeСO2) fractions of carbon dioxide in the hypopharynx of healthy volunteers during high-flow oxygen therapy through nasal cannulas in different physiological conditions.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Experimental | Experimental | High flow oxygen through nasal cannula, oxygen and carbon dioxide measurement in the hypopharynx |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| High flow oxygen through nasal cannula | Device | High flow oxygen through nasal cannula and measurement of oxygen and carbon dioxide fraction in the hypopharynx of healthy volunteers in different physiological conditions. |
| Measure | Description | Time Frame |
|---|---|---|
| Inspiratory oxygen fraction (FiO2) in the hypopharynx | Inspiratory oxygen fraction (FiO2) in the hypopharynx during different physiological conditions | 5 minutes |
| Expiratory oxygen fraction (FeO2) in the hypopharynx | Expiratory oxygen fraction (FeO2) in the hypopharynx during different physiological conditions | 5 minutes |
| Inspiratory fraction of carbon dioxide (FiCO2) in the hypopharynx | Inspiratory fraction of carbon dioxide (FiCO2) in the hypopharynx during different physiological conditions | 5 minutes |
| Expiratory fraction of carbon dioxide (FeCO2) in the hypopharynx | Expiratory fraction of carbon dioxide (FeCO2) in the hypopharynx during different physiological conditions | 5 minutes |
| Measure | Description | Time Frame |
|---|---|---|
| Respiratory rate (RR) | Respiratory rate (RR) during different physiological conditions | 5 minutes |
| Tidal volume (VT) | Tidal volume (VT) during different physiological conditions |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Andrey I Yaroshetskiy, MD, PhD, ScD | I.M. Sechenov First Moscow State Medical University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Sechenov University Clinic#4 | Moscow | Moscow | Russia |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 25981908 | Background | Frat JP, Thille AW, Mercat A, Girault C, Ragot S, Perbet S, Prat G, Boulain T, Morawiec E, Cottereau A, Devaquet J, Nseir S, Razazi K, Mira JP, Argaud L, Chakarian JC, Ricard JD, Wittebole X, Chevalier S, Herbland A, Fartoukh M, Constantin JM, Tonnelier JM, Pierrot M, Mathonnet A, Beduneau G, Deletage-Metreau C, Richard JC, Brochard L, Robert R; FLORALI Study Group; REVA Network. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med. 2015 Jun 4;372(23):2185-96. doi: 10.1056/NEJMoa1503326. Epub 2015 May 17. | |
| 34232336 |
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Measurement of the inspiratory (FiO2) and expiratory (FeO2) fractions of oxygen (FiСO2 and FeСO2, respectively), as well as the inspiratory and expiratory fractions of carbon dioxide (FiСO2 and FeСO2, respectively) in the hypopharynx of healthy volunteers during high-flow oxygen therapy through nasal cannulas in different physiological conditions
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| 5 minutes |
| Peripheral oxygen saturation (SpO2) | Peripheral oxygen saturation (SpO2) during different physiological conditions | 5 minutes |
| Modified ventilatory ratio (mVR) | Modified ventilatory ratio (mVR) during different physiological conditions. mVR = [RR * tidal volume* (PetCO2 (mmHg) - 4 mmHg)] / [predicted body weight (kg) * 100 * 37,5 mmHg] | 5 minutes |
| The ratio of oxygen saturation by pulse oximetry/inspiratory oxygen fraction to respiratory rate (ROX-index) | ROX-index (SpO2/FiO2/RR) during different physiological conditions | 5 minutes |
| Comfort | Visual-analog scale (VAS) for comfort evaluation (from 1 to 10, 1-full comfort, 10-full comfort) | 5 minutes |
| Background |
| Grieco DL, Maggiore SM, Roca O, Spinelli E, Patel BK, Thille AW, Barbas CSV, de Acilu MG, Cutuli SL, Bongiovanni F, Amato M, Frat JP, Mauri T, Kress JP, Mancebo J, Antonelli M. Non-invasive ventilatory support and high-flow nasal oxygen as first-line treatment of acute hypoxemic respiratory failure and ARDS. Intensive Care Med. 2021 Aug;47(8):851-866. doi: 10.1007/s00134-021-06459-2. Epub 2021 Jul 7. |
| 37165464 | Background | He Y, Zhuang X, Liu H, Ma W. Comparison of the efficacy and comfort of high-flow nasal cannula with different initial flow settings in patients with acute hypoxemic respiratory failure: a systematic review and network meta-analysis. J Intensive Care. 2023 May 10;11(1):18. doi: 10.1186/s40560-023-00667-2. |
| 34874419 | Background | Ospina-Tascon GA, Calderon-Tapia LE, Garcia AF, Zarama V, Gomez-Alvarez F, Alvarez-Saa T, Pardo-Otalvaro S, Bautista-Rincon DF, Vargas MP, Aldana-Diaz JL, Marulanda A, Gutierrez A, Varon J, Gomez M, Ochoa ME, Escobar E, Umana M, Diez J, Tobon GJ, Albornoz LL, Celemin Florez CA, Ruiz GO, Caceres EL, Reyes LF, Damiani LP, Cavalcanti AB; HiFLo-Covid Investigators. Effect of High-Flow Oxygen Therapy vs Conventional Oxygen Therapy on Invasive Mechanical Ventilation and Clinical Recovery in Patients With Severe COVID-19: A Randomized Clinical Trial. JAMA. 2021 Dec 7;326(21):2161-2171. doi: 10.1001/jama.2021.20714. |
| 35072713 | Background | Perkins GD, Ji C, Connolly BA, Couper K, Lall R, Baillie JK, Bradley JM, Dark P, Dave C, De Soyza A, Dennis AV, Devrell A, Fairbairn S, Ghani H, Gorman EA, Green CA, Hart N, Hee SW, Kimbley Z, Madathil S, McGowan N, Messer B, Naisbitt J, Norman C, Parekh D, Parkin EM, Patel J, Regan SE, Ross C, Rostron AJ, Saim M, Simonds AK, Skilton E, Stallard N, Steiner M, Vancheeswaran R, Yeung J, McAuley DF; RECOVERY-RS Collaborators. Effect of Noninvasive Respiratory Strategies on Intubation or Mortality Among Patients With Acute Hypoxemic Respiratory Failure and COVID-19: The RECOVERY-RS Randomized Clinical Trial. JAMA. 2022 Feb 8;327(6):546-558. doi: 10.1001/jama.2022.0028. |
| 40849448 | Derived | Yaroshetskiy AI, Krasnoshchekova AP, Tkachenko FD, Rubashchenko AV, Zubarev DD, Konanykhin VD, Savelenok MI, Nosenko MM, Merzhoeva ZM, Avdeev SN. Gas composition and pressure in the hypopharynx during high-flow oxygen therapy through a nasal cannula in healthy volunteers with different breathing patterns. BMC Anesthesiol. 2025 Aug 23;25(1):416. doi: 10.1186/s12871-025-03267-9. |