Introduction
There have been numerous recent inquiries regarding use of hyperbaric oxygen (HBO2) for patients with COVID-19. Questions have been raised pertinent to two possible mechanisms for HBO2 in this clinical context:
- support of oxygenation
- attenuation of pulmonary inflammation
Based on a review of the current literature, discussion with hyperbaric researchers working on this topic, and senior UHMS members, the following conclusions and recommendations are provided.
CONCLUSIONS AND RECOMMENDATIONS
- At this time there is insufficient evidence for the UHMS to endorse the routine use of HBO2 for COVID-19 patients outside the context of an IRB-approved clinical trial.
- The UHMS encourages appropriately powered, well-designed prospective clinical trials consistent with good clinical practice to determine whether the use of HBO2 is associated with clinically significant benefit in COVID-19 patients.
- Due to the potential for rapid clinical deterioration the treatment of COVID-19 patients with HBO2 should be confined to hospital-based programs comfortable with the management of critically ill patients, and as part of an IRB-approved clinical trial.
- The UHMS is unaware of any evidence that the use of HBO2 in this population is associated with patient harm or worsening clinical status. It is unknown what effects HBO2 will have on the infected lung. Further prospective research is needed to determine whether the use of HBO2 is associated with clinically significant pulmonary oxygen toxicity in this patient population.
- Hyperbaric medicine departments treating patients during this pandemic must maintain strict infection control measures. Please refer to the UHMS Guidelines for Infection Control.
BACKGROUND
The current COVID-19 pandemic has stretched medical systems and created considerable anxiety among health care workers and the general population. The search for novel treatments in an effort to reduce mortality and morbidity associated with COVID-19 is intense. The clinical findings of severe hypoxia and overwhelming inflammation have prompted questions around the use of HBO2.
A recent case-series of five patients in China1 has prompted multiple discussions related to the possible utility of HBO2 for COVID-19 patients. The mechanisms through which HBO2 may be beneficial are outlined below and include support of oxygenation and attenuation of pulmonary inflammation.
Support of Oxygenation
Patients with COVID-19-associated lung injury can develop severe hypoxemia, requiring increasing fractions of inspired oxygen. HBO2 is likely to raise arterial PO2 for the relatively brief period in which it can be realistically administered. However, arterial and tissue PO2 rapidly decrease to baseline at the end of hyperbaric exposure. It is hypothesized that COVID-19 patients have an accumulated oxygen debt, and that HBO2 offers a reprieve from this debt and possibly initiates recovery. There is also a concern about exacerbating pulmonary oxygen toxicity, especially in patients receiving high oxygen concentrations for prolonged periods before and after HBO2. Pulmonary oxygen toxicity was not reported in the case series in China1. It is unknown what effects (beneficial or adverse ) HBO2 will have on the COVID-19-affected lung.
Attenuation of Pulmonary Inflammation
HBO2 has demonstrated anti-inflammatory effects in other organs, but this has not been tested for COVID-19-associated lung injury. We are not aware of data supporting antiviral effects of HBO2.
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1 Ruiyong Chen, Xiaoling Zhong, Yanchao Tang, Yi Liang, Bujun Li, Xiaolan Tao, Changbo Liao.
The outcomes of hyperbaric oxygen therapy to severe and critically ill patients with COVID-19 pneumonia. Correspondence to: Dr. Xiaoling Zhong, HBOT Department of General Hospital of the Yangtze River Shipping, Wuhan China.
The Importance of IRB-Approved Prospective Research
At the time of publication there are at least six clinical trials nearing IRB approval or are already recruiting patients (refer to clinicaltrials.gov and the UHMS COVID-19 link for further details). Properly designed and conducted prospective trials will provide a sound foundation for future research and may result in a refinement of clinical practice. We must be cautious about implementing unsubstantiated treatment approaches.
There are multiple unanswered questions related to patient selection, timing of treatment initiation, hospital resource management, clinical efficacy, treatment protocols, treatment duration, and the logistical and safety issues associated with infection control. The many unknowns surrounding the use of HBO2 for COVID-19 patients underlie the UHMS’s position that there is insufficient evidence to endorse the use of routine adjunctive HBO2 for COVID-19 patients outside the context of an IRB-approved clinical trial.
Research on COVID-19 Patients with HBO2:
There are several clinical trials related to the use of HBO2 for COVID-19 patients. Please refer to the links below for further details and updates on study status.
- Clinical Trials search results in hyperbaric and COVID-19
- (this URL will be updated when we have a list of studies posted under the COVID-19 link). |
