Can alcohol intoxication be excluded as the cause of confusion following head injury?

Objective: To assess whether there is a breath alcohol level (BrAC) below which confusion in the head injured patient should not be attributed solely to the acute effects of alcohol

Method: Based in the Accident and Emergency Ward in Glasgow Royal Infirmary, a prospective observational study was carried out over a five month period. Patients admitted to the ward were recruited for the study if they had a primary diagnosis of head injury. The outcome measures recorded and analysed were sequential 2 hrly BrAC readings (mg/L) and Glasgow Coma Scale findings (Eye opening, motor and verbal responses). The relationship between these was investigated, which revealed additional relevant factors affecting level of consciousness.

Results: The breath alcohol analyser was found to be a useful non-invasive, quick and easy to use tool. The results obtained were consistent with the expected pattern of reducing BrAC levels over a 6 hour period. Within this group of patients, a poor correlation was found between each of the three responses of the Glasgow Coma Scale and BrAC readings. For those patients who remained confused, when their BrAC reading was less than 1 mg/L, other causes of a lowered level of consciousness were identified.

Conclusion: Confusion in the head injured patient with a BrAC of less than 1 mg/L, should alert one to the likelihood of causes other than alcohol intoxication.