The impact of total body water on breath alcohol calculations.

Gregor S Reiter,Markus Boeckle,Christian Reiter,Monika H Seltenhammer

doi:10.1007/s00508-020-01663-4

Abstract

SummaryDue to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h−1) and women (0.074 ± 0.017 mg/L h−1). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).

Highlights

Evidence of alcohol in the breath was already mentioned in the nineteenth century [1, 23]
The measured sample had a mean total body water (TBW) of 37.18 ± 7.53 L, a body surface area (BSA) of 1.854 ± 0.225 m2, and a BrAC0 of 0.358 ± 0.093 mg/L
We found significant correlations between TBW as well as BSA with breath alcohol concentration at time zero min, 90 min, 120 min, and 150 min in the complete sample and for the female and male subsets

Summary

Introduction

Evidence of alcohol in the breath was already mentioned in the nineteenth century [1, 23]. Liljestrand and Linde presented a conversion factor of 1:2000 from BAC to BrAC [23, 29]. This specific conversion factor, commonly shortened to Q, has already been discussed and revised in many different publications [10, 16, 21, 26, 33]. The usage of BrAC has a more important role than BAC in Austria because of the 13th amendment of the Road Traffic Act (StVO) in 1986 in which blood sampling was almost entirely replaced by breath testing [38]. While BrAC is the most frequently used measurement of alcohol intoxication in Austria, the usage and units of

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Results

Discussion

Conclusion