The results of a small comparative clinical trial published online in Emergency Medicine Journal reveals hyperbaric oxygen therapy (breathing oxygen under pressure – also known at HBO2 in this article) can resolve severe breathing difficulties experienced in COVID-19 patients much quicker when compared to standard therapy.

Takes 3 rather than 9 days; safe and effective for very sick patients, say researchers. Researchers wanted to find out if it reduced the risk of progression to respiratory distress, the need for mechanical ventilation, and death.

Three different public hospitals in Buenos Aires, Argentina participated in the trial using 40 COVID-19 adult patients experiencing severe breathing difficulties being randomly assigned to receive either standard therapy plus HBOT or HBOT only at 1.45 ATA. Despite oxygen saturation, none of the patients had been able to achieve an oxygen saturation of 90% (what is considered the lowest safe % of oxygen in the blood). Two-thirds of the patients were men with the average age being 55.

Standard therapy consisted of antibiotics (ceftriaxone 2 g/day and azithromycin 500 mg/day for 7days), dexamethasone 8 mg/day, paracetamol 1 g every 6 hours in case of high temperature, and monitoring for complications. Oxygen was supplied with a reservoir mask. HBO2 consisted of 5 or more sessions lasting 90 minutes each.

The final analysis was compiled looking at the 19 people in the HBOT group and the 20 patients in the comparison group.

The difference in oxygen saturation before and after treatment was significant for most HBO2 sessions, and showed an immediate and successive daily improvement, and at a steeper rate, than in those given standard therapy. The time taken to restore normal breathing was also shorter among those treated with HBO2: 3 days compared with 9 among those given standard therapy alone.

The researchers accept that their study involved a small number of patients who were relatively young. And because the study was stopped early due to its apparent success, this limited their capacity to assess other outcomes.

Nevertheless, they write: “Our findings suggest that supplementing oxygen through HBO2 treatment contributed to an increased [oxygen saturation] in patients with COVID-19 with severe hypoxaemia [breathing difficulties], with no significant adverse effects.

“Cases of severe COVID-19 that need mechanical ventilation have a high mortality risk. Therefore, novel therapeutic strategies are needed, and this study offers evidence supporting HBO2 treatment.”

They add: “This treatment could be easily available in various settings. Portable hyperbaric chambers offer a fast set up to avoid transferring patients to other hospital areas, attenuating the risk of virus transmission.”

But larger trials are needed to further confirm the treatment’s effects on survival, they say.

In a linked editorial, Dr John Kirkby of Washington University in St Louis, Missouri, cautions that the patients were not necessarily typical of all those admitted to hospital with COVID-19 and severe breathing difficulties.

And because none of them received antiviral drugs or monoclonal antibody preparations, this might also suggest they had less severe infection. The hyperbaric pressure was also relatively low.

Nevertheless, Kirkby concludes: “As we all look to improve our global capabilities to combat the effects of COVID-19, this study demonstrates the value of looking to make the most of available resources to properly evaluate novel treatment modalities, such as a lower cost, portable, lower pressure HBO2 to make a clinical impact on this pandemic.”

Cited from BMJ