Abstract
Hyperbaric oxygen therapy (HBO) is a short-term intermittent inhalation treatment with oxygen in a hyperbaric chamber under conditions of pressure higher than atmospheric pressure. Its effect cannot be narrowed down to an increased supply of O2 to the tissues.
In addition to fully saturated hemoglobin, the increased amount of dissolved O2 in plasma is also gaining in importance (Henry's law). This improves its diffusion and availability in tissues.
HBO also has many unique effects that are difficult to replace by other methods. It is, among other things, a signaling effect on DNA (gene transcription) with the influence of many cellular processes (expression of hormones, enzymes, factors, upregulation of receptors).
Antioxidant, protective (hemoxygenase-1, heat shock proteins) and genes for growth and repair factors and hormones are upregulated, while proinflammatory and proapoptotic genes are downregulated. Standard textbooks list a wide range of effects of hyperbaric oxygen therapy.
SARS-CoV-2 is primarily a respiratory disease. It also affects part of the innate (non-specific) immunity and activates the inflammatory cascade, which leads to the release of cytokines and chemokines, especially in the lungs.
Neutrophils and monocytes accumulate at the site of infection. Inflammation is probably the cause of ARDS (Adult Respiratory Distress Syndrome).
It also spreads outside the lungs and the systemic inflammatory response can take the form of a "cytokine storm" with devastating clinical consequences. The severe course of covid-19 disease is characterized by a marked systemic inflammatory response, associated, among other things, with extensive macrophage activation, vascular endothelial damage, and a hypercoagulable state.
This often manifests as deep vein thrombosis or microthrombosis. These first appear in the lungs, later spread to other organ systems with subsequent multiorgan dysfunction and disseminated intravascular coagulopathy (DIC).
In addition to affecting non-specific immunity and improving oxygen supply to tissues, HBO also shows activation of fibrinolysis. It is therefore considered in conjunction with anticoagulant therapy as a contribution to the treatment of patients with covid-19.