Citation

Bielefeld L, Auwärter V, Pollak S, Thierauf-Emberger A. Forensic Sci. Int. 2014; 247C: 23-27.

Affiliation

Institute of Forensic Medicine, University Medical Center Freiburg, Albertstraße 9, 79104 Freiburg, Germany.

Copyright

(Copyright © 2014, Elsevier Publishing)

DOI

10.1016/j.forsciint.2014.11.008

PMID

25528644

Abstract

BACKGROUND: The Widmark's equation (C [BAC]=A/p×r) is the most commonly used formula in legal medicine to estimate the blood alcohol concentration (BAC) from the amount of ingested ethanol and vice versa. Within a drinking experiment with a target BAC of 1.2g/kg, a 75-year-old participant reached a maximum BAC of 1.83g/kg and showed signs of severe ethanol intoxication, while the other nine subjects (age: 19-31 years) had BACs close to the target BAC. This incident brought up the question, if the Widmark's equation is an appropriate tool for aged persons.

METHODS: A drinking experiment with 50 elderly voluntary test persons (22 males, 28 females, mean age and range [males]: 69.7 years, 60-84 years, mean age and range [females]: 68.5 years, 61-78 years) was performed. The amount of ethanol leading to a BAC of 0.6g/kg was estimated individually using the Widmark's equation (used Widmark factors: 0.7 for males, 0.6 for females). After drinking, the blood ethanol concentrations were measured using headspace gas chromatography/flame ionization detection.

RESULTS: The measured maximum BACs of the elderly participants were significantly higher (α=0.01) than the target BAC (mean maximum BAC and range: 0.627g/kg, 0.3-0.81g/kg, for males: 0.616g/kg, 0.32-0.78g/kg, for females: 0.635g/kg, 0.3-0.81). The calculated Widmark factors showed a high coefficient of variation (for males: 0.7±0.138 [0.55-1.2, CV: 19.7%], for females 0.59±0.119 [0.46-1.08, CV: 20.2%]).

CONCLUSION: The results demonstrate that BAC calculations by Widmark's equation in elderly individuals may be complicated by a high variation of Widmark factors. There is a tendency to an elevation of the actual BAC with increasing age.

Language: en