Background: Traumatic brain injury (TBI) is classified into mild, moderate and severe, based on the Glasgow Coma Score (GCS). However, TBI patients are often influenced by ethanol, which in itself can attenuate the level of consciousness. This study investigated the effect of ethanol on the GCS group classification in TBI patients.
Methods: The Oslo University Hospital trauma database was searched for all patients admitted with a head injury where the blood ethanol concentration (BEC) had been measured (n = 1004). The effect of BEC on GCS groups was analysed using multivariate ordinal logistic regression.
Results: This study identified 546, 142 and 316 patients in the mild, moderate and severe groups, respectively. Increasing BEC by 1 g kg(-1) and pre-hospital intubation had OR = 1.34 and 16.34 for being in a more severe GCS group, respectively. Increasing head abbreviated injury scale (head-AIS) was significantly associated with being in a more severe GCS group. The modelled probability of detecting a head-AIS of 4 or 5 in a patient with BEC of 2.0 g kg(-1) was 20%, 38% and 65% in the mild, moderate and severe groups, respectively.
Conclusions: Increasing BEC was associated with increasing odds of being in a more severe GCS group. However, because the modelled probability of significant brain injury was high in patients with high levels of BEC, a reduced level of consciousness in intoxicated patients mandates further radiological investigations.
Keywords: TBI; coma; ethanol; head injury; prognosis.