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By no other research area in forensic medicine it could be shown more clearly how was maintained a basic medicolegal discourse leading to a continuous development of legal standards by advanced research, which included the newest methods of analytical possibilities and the latest scientific findings. The German forensic medicine has worked hard for an important share of the present day level in forensic ethanol research. The blood ethanol research became a Central European domain, for in the anglo-american society, it is not allowed to take a blood sample because of personality rights. The following passages report those selected areas in which German scientists rendered outstanding services.

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

Impairment due to ethanol is clearly a risk factor in deaths due to fire. However, it is less clear whether there is a physiological interaction between ethanol and carbon monoxide (CO) that would alter the carboxyhemoglobin saturation level (COHb sat.) that accounts for death. In an attempt to explore this issue further, 196 fire fatalities investigated by the Office of the Chief Medical Examiner, State of Maryland over a 3-year period were examined. COHb sat. and blood ethanol concentrations (BAC) were tabulated. Twelve cases positive for therapeutic or abused drugs other than lidocaine or atropine were excluded; 184 cases were included. The data indicate that ethanol does not affect the COHb sat. that accounts for death, since the percentage of cases positive for ethanol at a given COHb range shows no trends. Therefore, we conclude that although ethanol remains a risk factor in fire fatalities, the risk appears to be related to the impairment that it produces as opposed to a direct interaction with CO.

Problems related to blood contamination by other postmortem fluids in decomposed bodies (DB) make the interpretation of medicolegal blood alcohol levels (B EtOH) a very difficult task. So the aim of this paper is to show the utilization of vitreous humor (VH) as the biological fluid for an unequivocal determination of ethanol origin in DB for forensic purposes. Alcohol was determined in VH, blood (chest fluid - CF) and urine (Ur) collected from 27 DB in different states of putrefaction. A simple head-space gas-chromatographic method was used. In fifteen cases alcohol was found to be of endogenous production due to its absence in VH. In the twelve remainders, alcohol was detected in VH and CF in an atypical distribution. Examining the reliable scene and historical information together with the analytical data, ethanol origin in these cases was classified: endogenous production (3 cases), ingested (2 cases), both (2 cases), contaminated plus endogenous production (3 cases) and unable to determine (2 cases). According to the results obtained it was possible to conclude that alcohol analysis in VH is fundamental for determining the origin of ethanol detected in CF of DB. © 1999 Elsevier Science Ireland Ltd. All rights reserved.

An evaluation of the reliability of ethanol analysis in brain by the head-space gas chromatographic method has shown the following. 1. (a) This method may be used directly, without prior distillation, with homogenized brain tissue; 2. (b) a good correlation exists with values obtained on blood (blood/brain ratio of 0.97 and 1.32 for blood ethanol concentrations of 0.1 and 0.2 g/dl respectively); 3. (c) in non-preserved blood, there is a 15% deviance in the correlation resulting from changes in ethanol concentration; 4. (d) the same evaluation applied to ethanol analysis in liver reveals a poor correlation between the results in liver and blood; this is believed to result mainly from natural oxidative losses of ethanol in liver, and also from the variable fat content of the liver samples analyzed. Caution is emphasized with regard to interpretations of blood/brain and blood/liver ethanol concentration ratios for the purpose of determining pre- and post absorption stages of intoxication where samples involved are not properly preserved.

An experiment was carried out on rats to determine whether or not a skeletal muscle sample was suitable for the determination of ethanol concentration in a carcass. Gas chromatography was used to estimate the ethanol and n-propanol concentrations in the femoral muscle and intracardial blood. The ethanol concentration of each sample was corrected according to the moisture ratio of circulating blood, viz., 78.5%. The ethanol concentration ratio of blood to muscle was 1.03 two hours after ethanol administration. When the carcasses of rats pre-treated with ethanol were stored at 15 degrees C and 25 degrees C, respectively, the ethanol concentrations in muscle and blood increased with time. At all times the concentration was higher in blood than in muscle, and also higher in samples collected from the carcass stored at 25 degrees C than at 15 degrees C. When the control carcass was stored in the same manner, the postmortem production of ethanol was noticed in both blood and muscle. As in the experimental rats, the control rats exhibited a higher blood ethanol than muscle ethanol level. Again, the ethanol concentration was higher in samples collected from the carcass stored at 25 degrees C than at 15 degrees C. The ratio of ethanol to n-propanol was less than 20:1 in blood and less than 10:1 in muscle. These results suggest that skeletal muscle may be a suitable tissue for the postmortem detection of ethanol.

The acetaldehyde accumulation in blood during the equilibration time of samples processed by gas-liquid chromatographic headspace technique is reported. The quantitative loss of blood ethanol concentration is recorded at various temperatures and times of the preheating process. When the equilibration process is performed at 40 °C, minimal errors, due to ethanol oxidation, are observed.

The rate and kinetic order of ethanol elimination was evaluated in human volunteers. Part I of the study involved dosing individuals with alcoholic beverages on two separate occasions. Breathalyzer tests were performed at 15-min intervals for a period of 5 h. Attention was focused on values obtained after peak blood ethanol levels had been reached. The second part of the study included having samples drawn from alcoholics at predetermined intervals during recovery from alcoholic intoxication. Blood ethanol concentration data was analyzed for kinetic order and a comparison of ethanol elimination rates of alcoholics and non-alcoholics was made. The predicative capability of estimating a BAC from both the zero and first order theories was also investigated. It was concluded that ethanol elimination is a zero order process. For subjects classified as non-drinkers (consume less than 6 ounces of ethanol/month), the mean ethanol elimination rate as determined in the study was 12 +/- 4 mg/h. For subjects classified as social drinkers (consume more than 6 ounces but less than 30 ounces of ethanol/month), the mean ethanol elimination rate was 15 +/- 4 mg%/h, and for alcoholics, the mean ethanol elimination rate was 30 +/- 9 mg%/h. These results indicate that the rate of ethanol elimination increases with drinking experience.

A breath-alcohol screening device, Alcolmeter pocket model, was evaluated in a controlled field trial with policeman operating the instruments. The results of tests made with subjects before they drank alcohol were always zero. The standard deviation (S.D.) of breath alcohol determinations increased with increase in the concentration of alcohol in the sample, being 0.036 mg/ml at a mean blood-ethanol concentration of 0.53 mg/ml. The S.D. varied among subjects tested (from 0.022 to 0.053 mg/ml) as well as among the instruments used (from 0.023 to 0.054 mg/ml). The breath test results were on average less than the actual blood-ethanol concentrations when a 2100:1 blood/breath ratio was used to calibrate the Alcolmeter device. Blood ethanol ( x ) and Alcolmeter readings ( y ) were highly correlated ( r = 0.95 ± 0.018) and the regression equation was y = −0.017 + 0.95 x . At a mean blood-ethanol concentration of 0.50 mg/ml, the Alcolmeter instrument will indicate 0.46 mg/ml on average. The standard error estimate was 0.085 mg/ml, being 17% of the mean Alcolmeter reading and this corresponds to 95% confidence limits of ±0.17 mg/ml. The results of this study show that Alcolmeter pocket-model is a useful device for breath-alcohol screening purposes at a blood-alcohol level of 0.50 mg/ml. A blood/breath ratio of 2300 should be used to calibrate the Alcolmeter device.

Of approximately 5,000 forensic cases with a positive ethanol result, over 1,000 were available in which both blood and urine were present for comparison of ethanol content. Data were examined for calculation of the urine to blood ethanol concentration ratio, with the intent of evaluating the validity of predicting a blood ethanol level given a urine ethanol level. The overall urine to blood ethanol concentration ratio was 1.57:1 with a range of 0.7 to 21.0:1. The extremely wide range of values implies that a large degree of error would be introduced if a mean ratio was used when predicting a blood ethanol level from a urine ethanol level.

Post-mortem subdural ethanol levels have been proposed as a useful test in certain forensic cases involving head trauma, particularly when the time interval from injury to death may have caused a lowering of the blood ethanol concentration to insignificant or undetectable levels. This study of 75 autopsied persons from whom both blood and subdural ethanol levels were obtained, shows the usefulness of the subdural ethanol level, especially where there is a prolonged or unknown post-traumatic time interval. Use of such a test is recommended in these situations.

The relationship between ethanol levels in blood and bile was determined in human postmortem specimens. The influences of several physical properties — surface tension, specific gravity and viscosity — and bile lipid content on the blood/bile ethanol ratio were evaluated. A gas chromatographic direct injection technique was employed to determine the ethanol concentrations in postmortem blood and bile specimens. A positive correlation was established between the levels in the two fluids. No correlation could be found between the blood/bile ethanol ratios and the aforementioned physical properties of bile. Correction of the observed bile ethanol for lipid content had an insignificant effect on the ratio. The average blood/bile ethanol ratio was 1.03 ± 0.29 (range: 0.32-2.91). The wide range observed makes it undesirable to use bile ethanol concentrations to predict specific blood ethanol concentrations. However, under certain conditions, bile ethanol levels may be used to estimate blood concentrations within a range of values.

Post-mortem ethanol levels in blood were compared to corresponding levels in rib bone marrow, vitreous humor, urine and bile. In forensic toxicology, a good correlation between blood and a tissue or body fluid is needed to estimate a blood alcohol concentration when blood is unavailable or contaminated. In this study, direct injection and headspace gas-chromatographic techniques were employed to quantitate the ethanol concentrations. Comparable findings by these two techniques showed a reproducibility of results. When the determined bone marrow ethanol levels were corrected for the lipid fraction, a consistent correlation could be established between ethanol levels in blood and bone marrow. The relationship (linearity and ratio range) between ethanol levels in blood and corrected levels in bone marrow was better than that between blood and vitreous humor, bile or urine. This study showed that blood ethanol levels can be predicted by extrapolating the corrected rib bone marrow ethanol level.