[Correction of the alkylnitrite method for the detection of ethanol in blood taking into account toxico-kinetic and anthropometric data].

The correction coefficient for the systemic inaccuracy arising during determination of blood ethanol by alkylnitrite gas chromatography and concomitant calibration of aqueous solutions was estimated to equal 0.82; this finding was confirmed by the results of the toxico-kinetic assay for the measurement of total body water (TBW) from the kinetic curve characterizing the time dependence of ethanol concentration in the exhaled air, saliva, capillary and venous blood in combination with 4 anthropometric methods and (in several cases) direct physical detection of TBW. When detecting the blood ethanol level with a correction coefficient of 0.82, the mutual position of the kinetic curves for ethanol concentrations in the blood and the exhaled air (recalculated for the blood level with a coefficient of 2100) as well as in the blood and saliva agreed with that reported in the available literature; it significantly differed from the position of the curves obtained with a correction coefficient of 0.95. The causes accounting for the systematic inaccuracy and erroneous values of the correction coefficients in earlier studies are discussed.

[Correction of the alkylnitrite method for the measurement of ethanol in blood: direct experimental evidence].

A coefficient (multiplier) for the correction of a systemic inaccuracy of ethanol detection in the blood by the alkylnitrite method arising from calibration against an aqueous solution has been improved. The experiment was carried out as a multilaboratory study (with the participation of six laboratories). The value of the coefficient was estimated at 0.82 +/- 0.014 (SD) instead of 0.95 computed earlier (CV = 1.7%). The main factor influencing the value of the coefficient turned out to be the time of preparation of the model ethanol-blood mixture for comparison with the aqueous solution. The coefficient of 0.82 was obtained using fresh blood samples that of 0.93 to 0.96 with blood samples previously stored during 3-10 days. The results of the study suggest different ethanol distribution patterns in vivo and in vitro in the aqueous phase of the blood stored for a few days.

[Comparison of beta60, beta-slope elimination rates in different periods after alcohol intake].

Ethanol elimination rate, beta60, calculated from hourly measurements of alcohol concentration in blood after its acute intake at a dose of 0.8 g/kg body weight was compared with that after intake of 2 g/kg body weight (experiments 1 and 2 respectively). In the latter experiment, coefficients of variation (CV) of relative mean individual elimination rate proved to be practically equal (11 +/- 3%) for all subjects of the study group (men of different age). This value was significantly smaller than in either separate age group (young and adult men) included in experiment 1(18 +/- 5% and 29.9 + 9% respectively). For each man consuming alcohol at a dose of 0.8 g/kg body weight, ethanol elimination rates were also compared 20, 15, and 10 min after intake. Coefficients of variation in this experiment turned out to be significantly higher, viz. 39%, 60%, and 68% respectively. Similar variations of the ethanol elimination rate were observed in saliva (32-50%). Possible causes of these changes and differences as well as their practical implications are discussed in the context of reliability of forensic medical examination. It is concluded that calculation of individual elimination rate values should be made 60 min after intake of alcohol whereas values obtained within 20 min are unreliable.

[Ethanol elimination rate (beta60, beta-slope) in different age groups after intake of a moderate or high dose of alcohol].

Ethanol elimination rate (beta60) was measured in different age groups of men and women following its single intake at a dose of 0.8 g/kg body weight (experiment 1) and 2 g/kg (experiment 2). Samples of capillary blood were collected 20, 40, 60, 90, 120, and 300 min (experiment 1) or 360 min after the termination of the intake (experiment 2). The phase of alcohol elimination was deduced from the kinetic curve. Each alcohol dose was consumed during 1-2 minutes or 1-1.5 hours (experiments 1 and 2 respectively). The value of (beta60) in experiment 1 was estimated at 0.17 +/- 0.04 per thousand/hour in young men aged between 18-26 years, 0.22 per thousand/hour in adult men of 32-48 years, and 0.21 per thousand/hour in women aged between 19-41 years. The difference between alcohol elimination rates in young and adult men on the one hand and between young men and women on the other hand was statistically significant (p < 0.01 and p < 0.05 respectively). In the second experiment, ethanol elimination rate was practically identical in men of the above age groups (0.16 +/- 0. 02 per thousand/hour) and significantly higher than in 64-66 year-old men (0.14 +/- 0.03 per thousand/hour). The values of ethanol elimination rate in men of group 2 calculated by the Weedmark formula proved underestimated by 17 +/- 5% regardless of their age. Men of both age groups included in experiment 1 showed an alcohol excretion rate overestimated by 8 +/- 5% and 31 +/- 6% respectively compared with 10 +/- 7% in women. It is suggested that a single intake of alcohol may lead to an instantaneous rise in the hepatic concentration of ethanol unrelated to the consumed amount that however affects its metabolic rate. It is concluded that the duration of ethanol intake has greater effect on the rate of its elimination from the body than the amount of consumed alcohol, especially in alcohol-tolerant subjects.

[Estimation of ethanol concentrations in biological media. Comparison of alkylnitrite and direct vapor-phase methods].

Ethanol assays in the blood, saliva and urine were made according to two methods: alkylnitrite gas-liquid chromatography and direct vapor-phase method without thermostating. N-propanol was used as an internal standard. For saliva and urine the methods produced similar results. For blood, the direct vapor-phase method detected significantly lower level of ethanol compared to alkylnitrite one (p = 0.001). 24-h storage of the samples in refrigerator does not deviate the results. Recommendations are provided for most effective usage of each method.

[Kinetics of ethanol in biological sections].

Ethanol concentration in alveolocapillary blood (ACB), venous blood (VB), capillary blood (CB), saliva and urine was measured in healthy men and women aged 19-45 years 20, 40, 60, 90, 120, 180, 240 and 300 min after a single intake of 20% ethanol solution in soda water in a dose 0.8 g/kg body mass. Two types of kinetic curves were established. Calculations with Vidmark equation for different biomedia were made. Ethanol levels in all BM studied coincided in the resorption phase. In the elimination phase, ethanol concentration forms a sequence: ACB < saliva < VB < urine. Correlations and correlation coefficients of ethanol concentrations in different BM were estimated. The ethanol concentration correlation urine/ACB 1.71 +/- 0.15 and VB/ACB 1.45 +/- 0.07 is proposed for use in tests for alcohol intoxication.