Hyperbaric oxygen therapy applied research in traumatic brain injury: from mechanisms to clinical investigation

Traumatic brain injury (TBI) is the leading cause of mortality and morbidity for millions of young people and military personnel around the world every year. Regardless of severity, neurological dysfunction is a sequela of TBI. Although many preclinical and clinical trials have been carried out to explore its underlying pathophysiology, few effective treatment options have been used to ameliorate the prognosis of TBI, particularly with regard to the recovery of neurological deficits. Translational medicine has increasingly emphasized secondary brain injury, as distinguished from the mechanical damage occurring at the moment of traumatic impact; this includes cerebral ischemia, vasospasm, metabolic dysfunction, oxygenation absence and edema. Hyperbaric oxygen therapy (HBOT) is defined as the inhalation of pure oxygen in a hyperbaric chamber that is pressurized to greater than 1 atm. High concentrations of oxygen in the blood could affect brain tissue hypoxia readily thereby avoiding neuronal cell death through increased cerebral oxygen metabolism. Therefore, HBOT has been suggested as a scientific and effective treatment for TBI. The effectiveness and feasibility of HBOT has been confirmed by several studies. Following the widespread application of HBOT in cerebrovascular diseases and TBI, non-standard therapies frequently occur in primary care institutions, causing great controversy. The systematic analysis of the progress of both animal and clinical studies in this article provides the basis for further study of HBOT.