Hyperbaric oxygen for COVID-19 patients with severe hypoxia prior to vaccine availability.

Introduction: Few treatments have demonstrated mortality benefits among hospitalized hypoxic COVID-19 patients. We evaluated the use of hyperbaric oxygen (HBO2) therapy as a therapeutic intervention among hospitalized patients with a high oxygen requirement prior to vaccine approval. Methods: We extracted data on patients with COVID-19 hypoxia who required oxygen supplementation ranging from a 6L nasal cannula up to a high-flow nasal cannula at 100% FiO2 at 60L/minute with a 100% non-rebreather mask at 15 L/minute and were eligible for off-label HBO2 therapy from October 2020 to February 2021. We followed the Monitored Emergency use of Unregistered and Investigational Interventions or (MEURI) in conjunction with the consistent re-evaluation of the protocol using the Plan-Do-Study-Act (PDSA) tool [1]. We compared patient characteristics and used Fisher's exact test and a survival analysis to assess the primary endpoint of inpatient death. Results: HBO2 therapy was offered to 36 patients, of which 24 received treatment and 12 did not receive treatment. Patients who did not receive treatment were significantly older (p ≺ 0.01) and had worse baseline hypoxia (p = 0.06). Three of the 24 (13%) patients who received treatment died compared to six of 12 (50%) patients who did not receive treatment (RR ratio: 0.25, p = 0.04, 95% CI: 0.08 to 0.83). In the survival analysis, there was a statistically significant reduction in inpatient mortality in the treatment group (HR: 0.19, p = 0.02, 95% CI: 0.05-0.74). However, after adjusting for age and baseline hypoxia, there was no difference in inpatient mortality (hazard ratio: 0.48, p = 0.42, 95% CI: 0.08-2.86). Conclusion: The survival benefit of HBO2 therapy observed in our unadjusted analysis suggests that there may be therapeutic benefits of HBO2 in treating COVID-19 hypoxia as an adjunct to standard care.

Physiologic and biochemical rationale for treating COVID-19 patients with hyperbaric oxygen.

The SARS-Cov-2 (COVID-19) pandemic remains a major worldwide public health issue. Initially, improved supportive and anti-inflammatory intervention, often employing known drugs or technologies, provided measurable improvement in management. We have recently seen advances in specific therapeutic interventions and in vaccines. Nevertheless, it will be months before most of the world's population can be vaccinated to achieve herd immunity. In the interim, hyperbaric oxygen (HBO2) treatment offers several potentially beneficial therapeutic effects. Three small published series, one with a propensity-score-matched control group, have demonstrated safety and initial efficacy. Additional anecdotal reports are consistent with these publications. HBO2 delivers oxygen in extreme conditions of hypoxemia and tissue hypoxia, even in the presence of lung pathology. It provides anti-inflammatory and anti-proinflammatory effects likely to ameliorate the overexuberant immune response common to COVID-19. Unlike steroids, it exerts these effects without immune suppression. One study suggests HBO2 may reduce the hypercoagulability seen in COVID patients. Also, hyperbaric oxygen offers a likely successful intervention to address the oxygen debt expected to arise from a prolonged period of hypoxemia and tissue hypoxia. To date, 11 studies designed to investigate the impact of HBO2 on patients infected with SARS-Cov-2 have been posted on clinicaltrials.gov. This paper describes the promising physiologic and biochemical effects of hyperbaric oxygen in COVID-19 and potentially in other disorders with similar pathologic mechanisms.