HBO has been used as a therapeutic or an alternative therapeutic strategy for neurological diseases for many years. For most neurological diseases, HBO is being used without FDA and UHMS approval, so treatment occurs mostly in “free-standing” clinics. One of the key issues that has prevented HBO from becoming more mainstream is lack of scientific evidence to support a possible neuroprotective effect.
At the JoEllen Smith Medical Center in New Orleans, a 1994 study, The Perfusion Metabolism Encephalopathy Study, tracked about 200 patients, including children, with nearly 50 different neurological conditions, over five and a half years. The study became the basis for the 80-treatment protocol used in the U.S. for chronic neurological conditions.76
Zhang’s book, Hyperbaric Oxygen for Neurological Disorders, has a basic science section that explains the effect of HBO on brain physiology and metabolism as well as pathophysiology. The book emphasizes the potential use of HBO in stroke treatment. Stroke is the second leading cause of death and the leading cause of long-term disability in the nation. Targeting stroke has the potential to take HBO to a new level in medical use.77
Other experimental applications for HBO use include: traumatic brain injury, cerebral palsy, autism, multiple sclerosis, and amyotrophic lateral sclerosis.
Surgeons are using HBOT in a wide variety of indications: Traumatology, Orthopedics, Plastic and Reconstructive Surgery, Urology, Surgical Oncology, Wound Healing, Burns, Soft Tissue Infections, Cardiothoracic Surgery, Intensive Care, etc.78
It is easy to understand and appreciate the relationship between availability of oxygen and normal brain function. Even short interruptions in brain oxygen levels can effect brain damage. Blood flow and oxygen delivery are crucial for normal functioning of the brain. Oxygen transport to the mitochondria is important in sustaining aerobic cellular respiration and energy production. The restoration of adequate oxygen is critical for recovery after cerebral ischemia. HBOT’s ability to increase oxygenation makes it an obvious treatment option in cerebral ischemia.
HBOT improves oxygen delivery, reduces brain edema, improves brain metabolism, inhibits inflammation, enhances superoxide dismutase, and increases the flexibility of the red blood cells. HBOT is shown to demonstrate physiological changes in the brain. Results are shown by comparing before and after brain scans, called Single Photon Emission Computed Tomography (SPECT), a sophisticated imaging technology.
SPECT is an imaging technique that uses gamma rays and a gamma-emitting marker that is injected into the bloodstream. SPECT scans are significantly less expensive than PET scans and are able to provide 3D information. The pictures are typically presented as a cross-sectional view, but the view can be reformatted as needed by computer.
“Holes” or defects in the pictures of the brain represent decreases in perfusion (blood flow) related to possible decreases in neuronal (brain cell) activity. Standardized views are correlated as follows: average brain activity is shown in blue, higher activity in red, and very high activity in white.
Neubauer and others have used SPECT imaging before and after treatment with HBOT in stroke patients. Better perfusion rates are typically shown in the post HBOT pictures with increased blood flow indicating more activity in the brain areas that have been damaged.
HBOT is used to treat stroke patients at some private HBOT centers. Its use in ischemic stroke is based on the theory that damaged cells, called “idling” neurons, exist in the ischemic penumbra and that improving oxygenation may stimulate these cells to function normally. It is a practical early intervention; if patients receive HBOT immediately after stroke the patients may gain time by preserving penumbral tissue. There is some evidence of the possibility that HBOT also activates neural stem cells.79
Zhang says that “A number of clinical trials posted at the www.clinicaltrial.gov website are recruiting… indicating a recent revival of interest in HBOT, partly due to the significant results of basic research that has been done for a couple of years.” In animal research, HBOT has proven effective if introduced with the first six hours after acute brain insult. HBOT initiated beyond 12 hours resulted in an increased amount of damaged brain tissue. Other recent clinical trials suggest the efficacy of HBOT begun up to 48 hours after ischemic stroke.80
78 D. Bakker, D. & F. Cramer, (Eds.). (2002). Hyperbaric oxygen: Perioperative care. Flagstaff, AZ: Best Publishing Company, 55.