Moderate Alcohol Levels May Protect Brain After Trauma

But high blood levels are deadly, new study finds

MONDAY, Dec. 18, 2006 (HealthDay News) -- Low to moderate blood alcohol levels improve the chance of survival for people brought into emergency rooms with traumatic brain injuries, a Canadian study finds.

The death rate among the 1,158 patients in the study was 24 percent lower for those with moderate blood alcohol levels than those with no alcohol in their blood. But the death rate for those with high levels was 73 percent higher than for those with no blood alcohol.

While the study was not designed to determine the cause of the protective effect, animal trials point to an answer, said study lead author Dr. Homer C. N. Tien, a staff surgeon at the University of Toronto Sunnybrook Health Sciences Centre.

"When the brain is injured, a lot of the damage is secondary, occurring after the accident," Tien said. "Animal studies have suggested that for a variety of reasons, alcohol can help prevent that secondary brain injury."

Of the brain-injury patients in the study, 740 had no alcohol in their blood. Another 315 had low to moderate blood alcohol levels, up to 230 milligrams per deciliter of blood, while 103 had levels of 230 or higher.

There were 403 deaths in the hospital. Of those with low to moderate blood alcohol readings, 27.9 percent died, compared to a 36.3 percent death rate for those with no blood alcohol. Nearly half of the people with the highest blood alcohol readings -- 44.7 percent -- died, the researchers said.

The reduced risk of death associated with moderate alcohol levels was still present when the researchers adjusted for other factors, such as the severity of the injuries and blood transfusions.

The study is in the December issue of the Archives of Surgery.

The finding could someday lead to an alcohol-based treatment to limit brain damage from severe head injuries, Tien said, but a lot of work would have to be done to make that possible. "If this were tested very vigorously and found to have a benefit, it could theoretically be used for brain injuries," he said.

The study clearly does not suggest a reason to drink before driving, Tien said. "This [study] concerns post-injury effects," he said. "If you drink and drive, your chances of getting into a fatal accident are much higher than if you are sober."

Half the people who die from auto accidents and other causes of trauma do so before they reach a hospital, the researchers noted.

The apparent protective effect of alcohol has to do with something that happens in brain cells, the study found. The researchers also assessed more than 500 patients who suffered severe injuries to the torso and found no effect of blood alcohol levels on the death rate.

Dr. David Okonkwo, clinical director of the University of Pittsburgh Brain Trauma Research Center, said the study "opens new questions that we should be studying in experimental models of brain injury.

"We know that alcohol has a modulatory effect on the activity of brain cells, but we don't know what the influence is of that modulatory effect in the setting of a brain injury," he said. "In that regard, this is an interesting finding."

Okonkwo reiterated the warning about drinking and driving. "Having a modest amount may be beneficial should you have a brain injury, but having no alcohol at all in the system greatly reduces the chance that you will have a brain injury in the first place," he said.

More information

You can learn more about head injury by visiting the National Institute of Neurological Disorders and Stroke.

SOURCES: Homer C.N. Tien, staff surgeon, University of Toronto Sunnybrook Health Sciences Centre, Canada; David Onkonkwo, M.D., Ph.D., clinical director, University of Pittsburgh Brain Trauma Research Center; December 2006, Annals of Surgery
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