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Gauging Brain Injuries

Researchers devise formula for who needs a CT scan

FRIDAY, May 4 (HealthScout) -- A new scorecard for evaluating the risk of internal head injury could significantly reduce the number of costly brain scans while insuring that serious trauma not go undiagnosed, new research shows.

Canadian scientists say they've come up with a seven-item formula for emergency-room physicians that accurately reflects which patients should receive a form of X-ray scan called computed tomography, better known as CT.

The imaging technology can identify brain damage not readily apparent by a person's symptoms or behavior. But it is expensive and mushrooming in popularity, so reserving the technology for those who need it most is key, say the researchers, who report their findings this week in The Lancet.

"I would wager that in the U.S. we could easily reduce [the use of] CT by 50 percent," says Dr. Ian Stiell, an emergency medicine specialist at the University of Ottawa, and a co-author of the study.

An estimated 1 million head-injury patients go to emergency rooms in North America for treatment each year. Most have mild or moderate trauma, but undiagnosed lesions in the brain -- intracranial bleeding, for example -- can prove life-threatening.

The problem, however, is that doctors haven't had an efficient way of determining which patients are most at risk of hidden brain wounds. As a result, they're likely to err on the cautious side and rely too heavily on CT scans. In 1992, an estimated 270,000 CT scans-each costing between $500 and $800-- were performed in U.S. emergency rooms, experts say.

In the new study, Stiell, who is also a senior scientist at the Ottawa Health Research Institute, and his colleagues sought to create a formula for determining which patients with mild head injuries can safely avoid CT scans, and which need them most.

The researchers looked at the use of CT in cases involving about 3,100 Canadians with mild to moderate head trauma, all of whom scored between 13 and 15 on the Glasgow Coma Scale, a common measure of brain injury that gauges visual, verbal and motor function.

Eighty percent had a coma score of 15, the best. Only 8 percent were later found to have such "clinically significant" head injuries as internal bleeding, the researchers say. And only 1 percent required surgery or other neurological treatment, like easing pressure from fluid buildup around the brain.

Based on those findings, Stiell's group identified five major risk factors, any of which is sufficient to merit a CT scan and neurological treatment. The five are: a Glasgow Coma Scale score that failed to rise to 15 within two hours after the injury; a suspected open skull fracture; evidence of fracture at the base of the skull; two or more episodes of vomiting, or being 65 or older.

People with at least one of the five major risk factors made up 32 percent of the 3,100 subjects.

Stiell's researchers also found two medium-risk signs in 22 percent of the study participants: the inability to recall events 30 minutes or more before the injury, and how the wound happened. For these patients, a CT isn't necessary but they should be observed.

The remaining 46 percent of the patients had none of the seven signs and could be sent home right away, Stiell says.

In the United States, Stiell says, almost everyone who goes to the emergency room with a concussion gets a CT test. "But our stats are suggesting that only 54 percent need a scan," he says.

In Canada, only large hospitals are likely to have CT scanners, Stiell says, so the formula is especially valuable for doctors in small clinics. In these settings, "If the patient had none of the five high risk factors but one of the two medium ones they'd get watched. If there was any sign of deterioration, then they'd be transferred" to a hospital with the imaging machine.

But Dr. James Kelly, a Northwestern University neurologist who specializes in head injuries, says physicians consider medicine a blend of science and art, and they're loath to hitch all their diagnostic efforts to a checklist.

Kelly has written guidelines on how to treat sports-related concussions for the American Academy of Neurology. But he believes that many, if not most, doctors have ignored or tried to refute them.

The Canadian study "will have an impact, but not a big impact, because many doctors will simply ignore it," says Kelly, who is familiar with the report.

Still, he adds, "All of us in medicine need to figure out whether what it is we're doing makes sense and what the science is and what the justification is for ordering this test."

Stiell, whose group is now conducting a follow-up study to determine the validity of their formula, agrees that doctors in the United States will be reluctant to adopt the tool.

"I think it's a sad reality that in the U.S. many tests are unnecessary and they're ordered more in a defensive mode" to avoid liability, he says.

What To Do

For a brief explanation of CT scans, check out this site from the University of Colorado.

For more on head trauma, try the Brain Injury Association.

Or you can read these HealthScout stories on head injuries.

SOURCES: Interviews with Ian G. Stiell, M.D., senior scientist, Clinical Epidemiology Unit, Ottawa Health Research Institute; and James Kelly, M.D., professor of neurology, Northwestern University Medical School, Chicago, Ill.; The Lancet, May 5, 2001
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