The drunkest drinking driver in Sweden: blood alcohol concentration 0.545% w/v

This article examined drinking drivers (N = 81) who had unusually high blood alcohol concentrations (BAC > or = 0.400% w/v) when apprehended. These drinking drivers were investigated in relation to age, gender, weekday and time of day of arrest, amount of alcohol in the body and the rate of disappearance of alcohol from the blood.

The concentration of ethanol in whole blood was determined in triplicate by headspace gas chromatography and the rate of disappearance of ethanol (burn-off rate) was calculated when two blood specimens were taken about 1 hour apart (mean = 65 minutes, range = 33-110 minutes).

Seven of the 81 drunk drivers were women (9%) with a mean age of 40 years (range = 29-52 years) and 74 were men (91%) with a mean age of 44 years (range = 28-68 years). The mean, median and range of BACs for the women were 0.422% w/v, 0.413% w/v and 0.403-0.451% w/v, compared with BACs of 0.425% w/v, 0.416% w/v and 0.400-0.545% w/v for the men, respectively (p > .05). The BAC was not dependent on subjects' age (F = 1.04, 7/73 df, p > .05) nor the weekday when they were apprehended (F = 1.62, 6/74 df, p > .05). Most drunk drivers (49%) were apprehended between 12 noon and 6 PM, 40% were involved in traffic accidents and 17% did not hold a valid driving license. The mean (+/-SD) disappearance rate of ethanol from blood was 0.023% +/- 0.01% w/v per hour (N = 26), with a range of 0.013 to 0.061% w/v per hour.

Drinking alcohol to reach a BAC of 0.400% w/v or more and attempting to drive a motor vehicle indicates an exceptionally high cellular tolerance to the impairment caused by this drug. The alcohol burn-off rate was relatively high in these heavy drinkers (mean = 0.023% w/v per hour), which probably reflects the development of metabolic tolerance as well.