A case of a distinct difference between the measured blood ethanol concentration and the concentration estimated by Widmark's equation.
In the last century, several mathematical models have been developed to calculate blood ethanol concentrations (BAC) from the amount of ingested ethanol and vice versa. The most common one in the field of forensic sciences is Widmark's equation. A drinking experiment with 10 voluntary test persons was performed with a target BAC of 1.2 g/kg estimated using Widmark's equation as well as Watson's factor. The ethanol concentrations in the blood were measured using headspace gas chromatography/flame ionization and additionally with an alcohol dehydrogenase (ADH)-based method. In a healthy 75-year-old man a distinct discrepancy between the intended and the determined blood ethanol concentration was observed. A blood ethanol concentration of 1.83 g/kg was measured and the man showed signs of intoxication. A possible explanation for the discrepancy is a reduction of the total body water content in older people. The incident showed that caution is advised when using the different mathematical models in aged people. When estimating ethanol concentrations, caution is recommended with calculated results due to potential discrepancies between mathematical models and biological systems.
Institute of Forensic Medicine, Freiburg University Medical Centre, Freiburg, Switzerland. annette.thierauf@uniklinik-freiburg.de
Annette
A
Thierauf
Jürgen
J
Kempf
Jörg
J
Eschbach
Volker
V
Auwärter
Wolfgang
W
Weinmann
Heike
H
Gnann
D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D000428:Alcohol Drinking / Q000097:blood; D001834:Body Water; D002492:Central Nervous System Depressants / Q000097:blood*; D002849:Chromatography, Gas; D000431:Ethanol / Q000097:blood*; D005260:Female; D005410:Flame Ionization; D053593:Forensic Toxicology; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008875:Middle Aged; D055815:Young Adult
D002492:Central Nervous System Depressants; D000431:Ethanol