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.

Recurrence of Neurological Deficits in an F/A-18D Pilot Following Loss of Cabin Pressure at Altitude.

INTRODUCTION: Supersonic, high altitude aviation places its pilots and aircrew in complex environments, which may lead to injury that is not easily diagnosed or simply treated. Decompression illness (either venous or arterial) and environmental conditions (e.g., abnormal gases and pressure) are the most likely adverse effects aircrew often face. Though symptomatic aircrew personnel may occasionally require hyperbaric oxygen treatment, it is rare to require more than one treatment before returning to baseline function. CASE REPORT: This challenging aviation case details the clinical course and discusses the salient physiological factors of an F/A-18D pilot who presented with neurological symptoms following loss of cabin pressure at altitude. DISCUSSION: Most crucial to this discussion was the requirement for multiple hyperbaric oxygen treatments over several days due to recurrence of symptoms. The likelihood of recurrence during and after future flights cannot be estimated with accuracy. This case illustrates a degree of recurrences for neurological symptoms in aviation (hypobaric exposure to hyperbaric baseline environment) that has not previously been described. Robinson T, Evangelista JS III, Latham E, Mukherjee ST, Pilmanis A. Recurrence of neurological deficits in an F/A-18D pilot following loss of cabin pressure at altitude. Aerosp Med Hum Perform. 2016; 87(8):740-744.