The effects of hyperbaric oxygen therapy (HBOT) on coronavirus disease-2019 (COVID-19): a systematic review

Background Oxygenation serves as a cornerstone in the treatment of COVID-19, and several methods have been extensively studied so far. Herein, we aimed to systematically review the studies discussing hyperbaric oxygen therapy (HBOT) to examine its reported efficacy and adverse events in patients with COVID-19. Methods We systematically searched and retrieved the relevant articles using keywords on the online databases, including PubMed, Scopus, Embase, Web of Science, and Cochrane databases up to April 11th, 2021. The retrieved records underwent a two-step title/abstract and full-text screening process, and the eligible papers were identified. National Institutes of health (NIH) quality assessment tool was used for this study. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) with ID CRD42021269821. Results Eight articles from three countries were included. All the included studies had good and fair quality scores, with no poor studies included in this systematic review (Good: n = 5, Fair: n = 3). Studies were divided into clinical trials and case reports/series. Most of the studies used HBOT less than 1.5-2 absolute atmospheres (ATA) for 90 min sessions and thereafter sessions were decreased to 60 min. Trials demonstrated most of the patients recovered after receiving HBOT, and blood oxygen saturation increased after several sessions of HBOT. Conclusion Overall, HBOT seems to be a safe and effective oxygenation method in patients with COVID-19. However, there is limited knowledge and evidence regarding the effects and mechanism of HBOT in COVID-19 treatment, and further evaluations require extensive well-designed studies. Keywords: COVID-19, Hyperbaric oxygenation, Hyperbaric oxygen therapy, SARS-CoV-2