NEW YORK (Reuters Health) – Hyperbaric oxygen (HBO2) appears to resolves severe COVID-19 breathing problems in a median of three days compared with nine days with standard therapy, researchers in Argentina report.
“Our findings support the safety and efficacy of HBO2 in the treatment of COVID-19 and severe hypoxaemia,” they write in the Emergency Medicine Journal.
“Cases of severe COVID-19 that need mechanical ventilation have a high mortality risk,” Dr. Javier Roberti of the Institute for Clinical Effectiveness and Health Policy in Buenos Aires and his colleagues note. “Therefore, novel therapeutic strategies are needed, and this study offers evidence supporting HBO2 treatment.”
The team conducted a small randomized controlled trial in three urban public hospitals to investigate the safety and efficacy of HBO2 to treat hypoxemia in patients with COVID-19 and to determine their time to hypoxemia correction. They estimated they needed a sample size of 80 patients, with a planned interim analysis after learning the outcomes of 50% of participants.
Between July and November 2020, 20 patients with COVID-19 and an oxygen saturation (SpO2) of 90% or lower despite oxygen supplementation received standard treatment for respiratory symptoms (supportive treatment, ceftriaxone, azithromycin, dexamethasone and acetaminophen) while 20 received the standard treatment plus HBO2.
The treatment was given over seven days; HBO2 at 1.45 atmosphere absolute (ATA) was provided in ninety-minute sessions once per day for five or more days.
At admission, frequent symptoms were dyspnea, fever and painful swallowing. Mean SpO2 was 85.1%; the average age in the treatment group was 52.8 years compared with 57.7 years among controls.
Patients who received HBO2 reached at least 93% SpO2 in a median of three days versus a median of nine days for the control group (P<0.010). The odds ratio for recovery from hypoxemia in the HBO2 group at day 3 vs. the controls was 23.2 (P=0.001).
HBO2 treatment had no statistically significant effects on acute respiratory distress syndrome, mechanical ventilation, or thirty-day mortality.
The trial was stopped after the interim analysis results showed a marked benefit of HBO2 treatment.
In an accompanying editorial, Dr. John Kirby of Washington University in St. Louis, Missouri, writes, “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.”
Dr. Brian T. Garibaldi, an associate professor of medicine and the director of the Johns Hopkins Biocontainment Unit at The Johns Hopkins Hospital in Baltimore, Maryland, was surprised that patients in the study had overall higher oxygen levels weeks out from treatment.
“This suggests that there is a benefit beyond the initial delivery of higher levels of oxygen, perhaps mediated by an anti-inflammatory effect at the cellular level,” Dr. Garibaldi, who was not involved in the study, told Reuters Health by email.
“I am worried that there could still be unappreciated side effects of hyperoxia, because we know that in other contexts hyperoxia can worsen lung injury and hyperbaric therapy itself can cause lung injury,” he cautioned. “I think we need a larger study to really understand these key issues.”
Dr. Garibaldi also noted that the small number of participants and the younger age in the treatment group could have introduced bias. “The study did not report on the patients’ baseline oxygen support,” he added, “which could provide additional information about how balanced the groups were before treatment assignment.”
Dr. Chidinma Chima-Melton, a pulmonologist at UCLA Health in Porter Ranch, California, who also was not involved in the research, told Reuters Health by email, “We have limited tools to improve oxygenation in severely hypoxemic COVID-19 patients, so if HBO2 is a viable and safe alternative, we can theoretically save more critically ill patients by correcting their hypoxemia and buying them more time for their lungs to heal.”
She acknowledged the study’s strengths, including its design and multiple sites, but said it was unclear how generalizable the results are to patients in the United States. “Treating patients with antibiotics ceftriaxone and azithromycin is not standard of care in the U.S.,” she explained.
“With only 40 patients, the study was severely underpowered,” she added. “Larger multisite studies need to be done, but the study is intriguing.”
Dr. Roberti did not respond to requests for comments.
The study did not receive commercial funding. Three authors are employees of Biobarica Hyperbaric Medical Centers Net, which manufactures hyperbaric chambers.
SOURCE: https://bit.ly/3n0fK7q and https://bit.ly/3pZ9gb2 Emergency Medicine Journal, online December 14, 2021.
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