Current status of hyperbaric oxygen therapy for COVID-19.

Abstract

Since its outbreak in late December 2019, corona virus disease (COVID-19) has become a worldwide pandemic, hitting over 200 countries and regions around the world. In Japan, to prevent COVID-19 infection, the Japanese government recommends that people wear a mask, disinfect their hands with alcohol frequently, stay 2 m from others, avoid going out unnecessarily, and avoid the three Cs of “closed spaces with poor ventilation”, “crowded spaces with many people”, and “close contact”.1 Standard treatments for confirmed moderate and severe cases of COVID-19 infection in Japan are steroid, remdesivir, baricitinib and/or heparin, in addition to oxygenation supportive therapy, based on the Guideline of Medical Care for COVID-19, version 4.2, from the Japanese Ministry of Health, Labour and Welfare (https://www.mhlw.go.jp/content/000712473.pdf). The Japanese Society of Hyperbaric and Undersea Medicine released a position statement concerning COVID-19 infection on March 20, 2020, as hyperbaric oxygen therapy (HBO2) requires the three Cs, especially treatments in a multiplace chamber (https://www.jshm.net/file/covid19_1.pdf). Patients with a fever over 37.5°C, cough or sputum, and those with potential COVID-19 infection are not indicated for entrance into the HBO2 room. If a patient has confirmed COVID-19 infection, HBO2 is not recommended, excluding cases in which the benefit of HBO2 is superior to that without HBO2. The Japanese Society of Hyperbaric and Undersea Medicine has also declared that HBO2 is not recommended for the treatment of COVID-19-associated hypoxia. Instead, recommended treatment options include ventilator support or extracorporeal membrane oxygenation (https://www.uhms.org/images/MiscDocs/UHMS_Guidelines_-_COVID-19_V4.pdf). However, there have been five recent reports of patients with COVID-19-associated hypoxia using HBO2 to ameliorate their hypoxia (Table 1) as the increased amount of oxygen in the plasma due to HBO2 may mobilize stem cells, block the inflammatory cascade, interfere with interstitial fibrosis development in the lungs, delay the onset of severe interstitial pneumonia, and reduce the risk of multiple organ failure due to an overall abated COVID-19 viral load.2-5 These five reports included four case reports or case series and one analysis of 20 cases treated with HBO2 using a propensity-matched controls analysis. The report by Gorenstein et al.4 described the usefulness of HBO2 for patients with COVID-19 infection compared with controls without HBO2 (adjusted subdistribution hazard ratios were 0.37 for inpatient mortality [P = 0.14] and 0.26 for mechanical ventilation P = 0.046]). Based on these preliminary reports, a randomized control study to verify the safety and utility of HBO2 for patients with COVID-19, even severe cases, is now ongoing (https://www.uhms.org/images/Position-Statements/HBO2_and_COVID_8-10-2020_clinicaltrials_8-12-2020.pdf). No funding information provided. Approval of the research protocol with approval no. and committee name: This report was approved by the review board of our hospital (approval number: 298). Informed consent: N/A. Registry and registration no. of the study/trial: N/A. Animal studies: N/A. Conflict of interest: The author do not have conflict of interest to declare.