Hyperbaric Oxygenation reduces hypoxia in the body:

Hypoxia is not enough oxygen circulating in the body for a variety of reasons. Hypoperfusion, or a poor or decreased blood flow into brain tissues leads to hypoxia in the brain.  Hypoxia triggers electrical failure (ion activity) in brain cells. Worsening hypoxia may eventually result in ion pump failure, which ultimately leads to cell death.  Cells that have electrical failure but retain ion pump ability have been described as “idling” because they remain alive but non-functional.  SPECT studies (a type of brain “picture” that shows how blood is perfusing the brain) have confirmed the presence of these “idling cells,” which surround areas of focal ischemia and comprise the “ischemic penumbra” (area around dead cells that is alive but has limited oxygen supply). Restoring oxygen can salvage the penumbra cells and return them to  functioning status.  

Over time, victims of hypoxia, such as those who have had a stroke, find that they begin to recover function generally within the first three months after the event.  Hyperbaric oxygenation increases the likelihood of a return to function of the penumbral cells, anytime after the event, with better results before atrophy (a loss of body tissue or progressive decline) sets in. This may explain why the acute findings of hypoxic events are poor predictors of ultimate clinical outcomes.