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Hyperbaric oxygen as an adjuvant treatment for patients with COVID-19 severe hypoxaemia: a randomised controlled trial
  1. Mariana Cannellotto1,
  2. Mariano Duarte2,3,
  3. Guillermo Keller4,5,6,
  4. Ramiro Larrea7,
  5. Eleonora Cunto8,
  6. Viviana Chediack8,
  7. Mariela Mansur7,
  8. Daniela M Brito7,
  9. Elizabeth García5,
  10. Héctor E Di Salvo5,
  11. Fabrizio Verdini1,
  12. Cecilia Domínguez8,
  13. Liliana Jorda-Vargas1,
  14. Javier Roberti9,10,
  15. Guillermo Di Girolamo4,6,
  16. Esteban Estrada1,11
  1. 1 Research Department, Argentine Association of Hyperbaric Medicine and Research (AAMHEI), Buenos Aires, Argentina
  2. 2 Laboratory of Arterial Hypertension, Cardiology Department, Hospital de Clinicas Jose de San Martin, Buenos Aires, Argentina
  3. 3 Segunda Cátedra de Fisiología, Universidad de Buenos Aires Facultad de Medicina, Buenos Aires, Argentina
  4. 4 Instituto Alberto C Taquini de Investigaciones en Medicina Traslacional - Facultad de Medicina, Universidad de Buenos Aires and CONICET, Buenos Aires, Argentina
  5. 5 General Medicine, Hospital General de Agudos Donación Santojanni, Buenos Aires, Federal District, Argentina
  6. 6 Tercera Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
  7. 7 General Medicine, Municipal Hospital of San Isidro, San Isidro, Argentina
  8. 8 Intensive Care Unit, Hospital de Infecciosas Dr Francisco Javier Muñiz, Buenos Aires, Argentina
  9. 9 Qualitative Research in Health, Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina
  10. 10 Centre for Research on Epidemiology and Public Health (CIESP), CONICET, Buenos Aires, Argentina
  11. 11 Hyperbaric Medicine, Hospital Alta Complejidad JD Perón, Formosa, Argentina
  1. Correspondence to Dr Javier Roberti, Institute for Clinical Effectiveness and Health Policy, Buenos Aires, Argentina; javierroberti{at}


Background Hyperbaric oxygen (HBO2) therapy has been proposed to treat hypoxaemia and reduce inflammation in COVID-19. Our objective was to analyse safety and efficacy of HBO2 in treatment of hypoxaemia in patients with COVID-19 and evaluate time to hypoxaemia correction.

Methods This was a multicentre, open-label randomised controlled trial conducted in Buenos Aires, Argentina, between July and November 2020. Patients with COVID-19 and severe hypoxaemia (SpO2 ≤90% despite oxygen supplementation) were assigned to receive either HBO2 treatment or the standard treatment for respiratory symptoms for 7 days. HBO2 treatment was planned for ≥5 sessions (1 /day) for 90 min at 1.45 atmosphere absolute (ATA). Outcomes were time to normalise oxygen requirement to SpO2 ≥93%, need for mechanical respiratory assistance, development of acute respiratory distress syndrome and mortality within 30 days. A sample size of 80 patients was estimated, with a planned interim analysis after determining outcomes on 50% of patients.

Results The trial was stopped after the interim analysis. 40 patients were randomised, 20 in each group, age was 55.2±9.2 years. At admission, frequent symptoms were dyspnoea, fever and odynophagia; SpO2 was 85.1%±4.3% for the whole group. Patients in the treatment group received an average of 6.2±1.2 HBO2 sessions. Time to correct hypoxaemia was shorter in treatment group versus control group; median 3 days (IQR 1.0–4.5) versus median 9 days (IQR 5.5–12.5), respectively (p<0.010). OR for recovery from hypoxaemia in the HBO2 group at day 3 compared with the control group was 23.2 (95% CI 1.6 to 329.6; p=0.001) Treatment had no statistically significant effect on acute respiratory distress syndrome, mechanical ventilation or death within 30 days after admission.

Conclusion Our findings support the safety and efficacy of HBO2 in the treatment of COVID-19 and severe hypoxaemia.

Trial registration number NCT04477954.

  • COVID-19
  • hyperbaric medicine
  • respiratory

Data availability statement

Data are available on reasonable request. Additional information available on request to authors.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Data are available on reasonable request. Additional information available on request to authors.

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  • Handling editor Lara Nicole Goldstein

  • Contributors Concept: MC, GK and EE. Design: MC, GK, LJ-V and DM. Data collection: MD, GK, RL, EC, VC, MM, DMB, EG, HEDS, FV, CD and GDG. Data analysis: MC, MD, GK, LJ-V and EE. Visualisation: LJ-V and JR. Interpretation: MC, MD, GK, RL, DMB, HEDS, FV, LJ-V, GDG, JR and EE. Investigation: MC, MD, GK, LJ-V, JR and EE. Draft writing: LJV, MC and JR. Guarantor: MC. All authors reviewed and commented the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests MC is medical director, FV is medical liaison and LJ-V is scientific director and management in clinical research of Biobarica Hyperbaric Medical Centers Net.

  • Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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