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Driving-impaired patients leaving the emergency department. The problem of inadequate instructions.

STUDY OBJECTIVE
We evaluated the frequency with which blood alcohol concentrations were obtained in emergency department patients with presumed alcohol impairment, whether physicians counseled impaired patients not to drive, and whether safe transportation was available.


DESIGN
Retrospective chart review and search of the North Carolina Driver History file.


SETTING
Emergency departments of a university and affiliated Veterans Affairs Medical Center (VAMC).


PATIENTS
Consecutive adult patients at the university (n = 1554) and VAMC (n = 1461) emergency departments. Patients with presumed alcohol-induced impairment (university, 75; VAMC, 88) who did not require hospital admission were identified. Presumed alcohol-induced impairment was defined by any of the following: nurse or physician note specifying the patient was intoxicated; indication in the medical record that the patient had alcohol on their breath; claim by the patient of alcohol use the day of evaluation; or measurement of blood alcohol concentration.


MEASUREMENTS AND MAIN RESULTS
Blood alcohol concentrations were measured in 80% of presumed alcohol-impaired university patients (median blood alcohol concentration, 45 mmol/L) and 68% of VAMC patients (median blood alcohol concentration, 58 mmol/L). Driving skills deteriorate with blood alcohol concentrations of 11 mmol/L or greater; however, 63% of university and 88% of VAMC patients with measured blood alcohol concentrations of 11 mmol/L or greater were still impaired when discharged. Only 3.5% of university and 8.7% of VAMC patients impaired at discharge were advised not to drive, whereas 31% of university and 20% of VAMC patients impaired at discharge were supervised by a responsible person. The prevalence of previous driving-while-impaired convictions was high (university, 34%; VAMC, 58%).


CONCLUSIONS
Presumed alcohol-impaired patients seen in emergency departments frequently have blood alcohol concentrations measured. Despite documented evidence of driving impairment there is little evidence that such patients are counseled not to drive or that safe transportation home is available.