Effect of alcohol intoxication on the diagnosis and apparent severity of brain injury.

Because alcohol intoxication is common among brain-injured patients, we performed this study to determine the extent to which alcohol alters the initial assessment of brain injury severity in these patients by depressing the level of consciousness. The Glasgow coma scale was used to measure the level of consciousness of 257 brain-injured adults admitted to the University of Virginia Hospital, both on arrival in the emergency room and 6 to 10 hours later. Improvement in the level of consciousness between the first and second measurements was significantly related to the blood alcohol concentration on admission. Patients with the highest blood alcohol concentrations showed the greatest improvement. Most of this effect occurred in patients with a blood alcohol concentration of 0.20% or higher. Alcohol intoxication is a potential source of bias in the clinical classification of brain injuries according to severity.