Blood Ethanol Level Influences Presenting Glasgow Coma Scale Interpretation After Traumatic Brain Injury: A Transforming Research and Clinical Knowledge in Traumatic Brain Injury Study.

BACKGROUND AND

OBJECTIVES

Traumatic brain injury (TBI) often involves alcohol intoxication, yet the effects of elevated blood alcohol content (BAC) on the Glasgow Coma Scale (GCS) are poorly understood. This study investigates the effect of alcohol intoxication on the initial GCS evaluation of patients with TBI.

METHODS

Data from a subset of patients enrolled in the Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) prospective cohort study were analyzed through Mann-Whitney and Fisher exact tests, and regression analyses as appropriate. Clinical and demographic data were reviewed, and patients were grouped by presenting BAC.

RESULTS

In the cohort of 2032 patients, presenting BAC was available for 1448 patients; 25.6% (n = 370) of whom had a BAC ≥0.08 (+BAC). Intoxicated patients exhibited higher rates of recreational drug use (35% vs 19%; P < .001). Despite no difference in injury severity scores between the groups, +BAC patients were more likely to have a positive head computerized tomography (66% vs 53%; P < .001), a lower GCS at presentation (12 vs 13; P < .001), and be categorized as severe TBI (GCS 3-8) at emergency department presentation (26% vs 17%; P < .001). Importantly, the effect of BAC on the GCS remained significant after the use of multivariable regression analysis to control for Marshall score, nonhead injury severity scores, age, sex, and cannabinoid and hard drug use ( P = .007). Multivariable regression analysis also demonstrated a dose-dependent effect with only the most intoxicated patients (BACs 0.16-0.24 and ≥0.24) significantly affecting the GCS.

CONCLUSION

Patients with elevated BACs scored approximately 1 point lower on the GCS than patients with BACs under 0.08. BAC's effect on the GCS persisted even after controlling for other covariates by multivariable regression analysis. Providers should be aware of this when initially evaluating intoxicated patients with TBI as it can affect their clinical management.