WASHINGTON, D.C. -- A small-scale study suggests that hyperbaric oxygen therapy may hasten recovery from stroke and save millions or even billions of dollars annually in health care costs, a medical researcher says.
The study also indicates that the new approach could give doctors a vital fourth hour to intervene after the onset of stroke. Current approaches are limited to about three hours.
Dr. Richard Neubauer, the director of the Ocean Hyperbaric Center, says that in a study involving 32 victims of acute stroke (within four hours of onset), 25 percent of those receiving hyperbaric oxygen therapy were discharged from the hospital within 24 hours. In comparison, none of the 16 stroke victims receiving standard treatment was discharged in less than 5 days and all but two were hospitalized 10 days or longer.
Neubauer presented the results of his study today at a meeting of the Space and Underwater Research Group of the World Federation of Neurology. The meeting is being coordinated by the Stroke Research Center of the Wake Forest University Baptist Medical Center.
But Dr. Stephen Thom, the president of the Undersea and Hyperbaric Medical Society, cautions that medial researchers still do not have a clear understanding of why hyperbaric oxygen therapy works and that more studies are needed to validate these results.
There is also disagreement within the medical community over whether hyperbaric oxygen therapy should be considered a treatment in itself or simply a tool to extend the time for using other treatments, said Dr. George Howard, professor of public health sciences and neurology at the Wake Forest University Baptist Medical Center.
Doctors hope that one result of their meeting this week will be a trial to further investigate hperbaric oxygen therapy, said Howard, who is on the planning committee for the trial. This could be either a large-scale pilot study, or a clinical trial involving 30 to 50 medical centers.
"The task is to see if we can come up with a consensus as to what the next step is," said Howard.
Stroke is the third leading cause of death in the United States and the leading cause of disability. It happens when a blood vessel serving the brain hemorrhages, or is blocked by a blood clot, impairing the flow of oxygen to that part of the brain. Each year roughly 600,000 Americans suffer a stroke, according to the American Heart Association.In 1994, almost 155,000 people died from stroke.
Hyperbaric oxygen therapy can revive dormant brain cells that have ceased functioning after a stroke, Neubauer said. Hyperbaric oxygen therapy placing patients in a whole-body chamber oin which atmospheric pressure can be raised to two or more times normal level.and breath pure oxygen
The key, he said, is to combine this therapy with a diagnostic test called single photon emission computerized tomography, or SPECT, scanning. SPECT scanning is used mostly by cardiologists, Neubauer said, but with the appropriate software it can be used to determine if a stroke victim has viable dormant brain cells that survived the stroke. These cells, surrounding the brain cells killed by the clot, are getting enough oxygen to survive but not enough to function properly.
By putting these victims in a hyperbaric chamber breathing pure oxygen at 1.5 times the normal atmospheric pressure, far more oxygen is dissolved into the blood plasma and other bodily fluids, including the cenral nervous system fluid.
"You are giving free molecular oxygen immediately available for metabolic use" to the impaired cells, Neubauer said.
"Hyperbaric oxygen therapy with SPECT scanning may at times predict which patients are going to recover," Neubauer said. "Thus, patients may be treated at home with all modalities of physical therapy and continued hyperbaric oxygen."
This could have far reaching economic consequences, he said. "If we can take one day off the hospital stay, one week off the nursing home and one week off the physical therapy, the savings are in the billions."
Currently the only treatment for acute stroke victims is to inject clot-busting drugs within three hours. But this is used in only about 5 percent of all stroke victims, Neubauer said, because the drugs cannot be given to victims with hemorrhages, with hypertension, or who may not tolerate the side effects of the drugs. Hyperbaric oxygen therapy has none of these limitations, and can be used up to four hours after stoke onset.
An extra hour represents a significant improvement, given the time it can take for a family to recognize that a stroke is occurring, get the patient to a major medical center from an outlying area, and to wait while brain images are made to determine if the stroke is caused by a brain hemorrhage or a blood clot.
Theoretically, Neubauer said, the combination of hyperbaric oxygen therapy with clot-busting drugs could extend the window for intervention to up to six hours.
Neubauer said he hopes a large-scale clinical trial will attract the attention of hospitals and health-maintenance organizations, which are being financially squeezed into finding more cost-effective ways to deliver care.
"The thing that will save it is its cost effectiveness."
The four-day meeting -- the Congress on Cerebral Ischemia, Vascular Dementia, Epilepsy and CNS Injury: New Aspects of Prevention and Treatment from Space and Underwater Exploration -- concludes today at the Washington Marriott Wardman Park Hotel, formerly the Sheraton Washington.