Below is a description of methodology for
the calculation of alcohol dose (in mls) to achieve a peak blood alcohol
level. This method has been most
recently described in:
The advantages of this
method over the simplier Widmark equation are outlined here:
Methods
The alcohol dose required to produce a
specific peak BAL is a function of the participant’s total body water (TBW),
duration of the drinking period (DDP), time to peak BAL (TPB), and alcohol
metabolism rate (MR). Specifically:
Alcohol dose (g)
= ((10 * BAL * TBW)/0.8) + (10 * MR * (DDP + TPB)) * (TBW/0.8)
In the above formula, alcohol dose is
measured in grams, BAL in g/100 ml (e.g.,
.010 g/100 ml) DDP and TPB in hours and TBW in liters. We use 0.015
g/100ml/h as the average metabolism rate for all participants. Additionally, we
assumed that participants reached their peak BAL at 0.5 hours after cessation
of drinking. TBW is determined from gender-specific regression equations
provided in:
Watson, P. E. (1989). Total body water and
blood alcohol levels: Updating the fundamentals. In K. Crow & R. Batt
(Eds.) Human metabolism of alcohol (Vol. 1): Pharmacokinetics,
medicolegal aspects, and general interest (pp. 41-58).
Specifically:
Men: TBW (l) = 2.447 - 0.09516* AGE (years) + 0.1074*
HEIGHT(cm) + 0.3362* WEIGHT(kg)
Women: TBW (I) = -2.097 + 0.1069* HEIGHT(cm) + 0.2466*
WEIGHT(kg)
Finally, alcohol dose is converted from
grams to milliliters by dividing by the density of alcohol at 24° C, 0.7861
g/ml. Application of this procedure in several recent studies in our lab has
resulted in both exceptional accuracy and minimal variability in observed peak
BALs—especially relative to what is typically reported in alcohol challenge
studies.
BAL Dosing Software
A simple windows-based program (The BAL Calculator)
that performs these calculations is available.
You can download a zipped file that
contains all installation files or you can install directly by following this link (This should
probably not be attempted through a slow dial-up connection). Source code (zipped
files coded in Visual Basic) is also available for download.
Instructions for using the BAL Calculator
are available.
Updated
on 09-21-06 by J. Curtin