The program ALCOMETER by Saturn ® Data International gives you an opportunity to make automated calculation of maximal theoretically possible concentration of ethanol in blood (per mille ‰) depending on the volume and strength of consumed drinks by Widmark formula
- Usage of alcohol in excessive amounts is dangerous for your health and the health of others, driving under the influence of alcohol is unacceptable.
- These automated calculations are approximate, they can not be invoked as evidence in court and challenge the laboratory results.
- For accurate and rapid determination of actual alcohol content in individual human body without resort of invasive methods (associated with blood test) you have the opportunity to use specialized instruments - professional Alcotesters by Dräger Concern (Germany).
Terms and definitions.
Blood alcohol content is perceived as the concentration of ethanol expressed in per mille.
Per mille is a thousandth of volume, so that the expression "blood alcohol concentration is 0,2 ‰ (per mille)" one should understand that in one liter of blood (or at 1000 milliliters) there is 0.2 milliliters of pure ethanol.
Knowing the concentration of ethanol in the blood at any given time, it is possible to calculate at any time the concentration of alcohol and the amount of certain alcoholic drinks used for reaching such concentration. Besides, it is possible to calculate the time required for complete alcohol excretion from the body, that is, the time interval until the occurrence of "sobriety", that is important, for instance, when driving and operating machinery.
The countdown of the scientific approach to the calculations began since the appearance of works of Erik Matteo Prochet Widmark, Swedish explorer who in the 20-th of the twentieth century conducted a series of studies on this subject in Germany and published his "Theoretical basis and practical application of forensic determination of alcohol» (Widmark EMP (1932) Die theoretischen Grundlagen und die praktische Verwendbarkeit der gerichtlichmedizinischen Alkoholbestimmung. Urban & Schwarzenberg, Berlin Wien). It was there where "Widmark formula" was published which is in use up to now and described the method of determining of alcohol concentration, subsequently named after him:
(formula 1), where
- c - the concentration of alcohol in blood ‰ (per mille),
- A – the amount of pure alcohol drunk in grams,
- m – body mass in kilograms,
- r - Widmark distribution coefficient (0.70 - for men, 0.60 - for women).
To get the actual concentration of ethanol in blood by making calculations to formula 1, you must subtract from 10% to 30% of the so-called resorption deficit from the mass of alcohol consumed - A, because some part of alcohol will not reach the peripheral blood.
However, it should be noted that actually you must take into consideration factors affecting the concentration of alcohol in human blood.
Here are factors that affect the concentration of alcohol in the body: body weight, height, sex, period of time during which alcohol was consumed, type of alcoholic drink that was consumed, satiety / hunger, kind of food consumed before, during and after alcohol taking up, resorption rate and the coefficient of reduction, the rate of metabolism and excretion of ethanol from the body, especially the process of ethanol oxidation in the liver of a particular person (subject to a number of enzymes that are active and determine individual tolerance to alcohol and depends on heredity), addiction to alcohol, and other.
Resorption factor - mass of alcohol absorbed by a man.
Reduction factor - mass part of a man, affected by alcohol.
Pharmacokinetics of ethanol.
- Phase of absorption or resorption: alcohol enters the body normally during the use of alcoholic drink and is absorbed through the mucous membranes of gastrointestinal tract. Absorption begins in the mouth, esophagus and stomach. However, because of the short time of contact of mucous membranes of the mouth and esophagus with alcohol the part of resorbed alcohol is very small. The stomach absorbs about 20% of total consumed amount of alcohol. Virtually, all of the rest of alcohol is absorbed in small intestine. With an empty stomach the resorption ends in about 30-60 minutes. After the absorption into blood stream, a small part of alcohol, unchanged, begins to flow through the lungs, some of it released in the stomach once again.
Resorption deficit: some part of alcohol, for unknown reasons to date, disappear and fall short to reach the peripheral blood stream. On empty stomach the loss of consumed alcohol is about 10%, and 30% on full stomach. Resorption deficit also depends on the concentration of alcohol in drink.
- Phase of diffusion or distribution of alcohol in the body media: at first the alcohol concentration in the arterial blood is higher than in the venous, followed by the alignment of concentrations. Organs with higher water content reach higher concentrations than organs with low water content. Particularly fast concentrations are equalized in organ and in blood stream in brain and kidneys.
- Phase of removal or elimination: reduction of alcohol concentration in blood in the course of time is mainly due to the chemical reaction with the conversion of ethanol into acetaldehyde with the help of hepatic enzyme alcohol dehydrogenase. In this way 90-95% of the resorbed alcohol is utilized.
Hourly elimination. The reduction of ethanol concentration in blood E. Widmark suggested indicate as β, reduction of concentration in an hour, respectively, β (60). Numerous, independent of each other studies in many countries have shown that the average index of physiological elimination of ethanol per hour corresponds to 0,15 ‰. This is the so-called average rate of elimination of ethanol from the body. It does not depend on sex, or body weight, and even (!) does not vary in cases of liver disease advanced stages. In practice, this parameter may be used for calculations for the attainment of a stage of "sobriety." For example, elimination of 1,5 ‰ of alcohol from the blood will take 10 hours. A man who consumed alcohol with the maximum concentration of 3 ‰ (in blood) will be sober in about 20 hours.
Alcotester (Breathalyzer) is a device for quantitative determination of alcohol in human body, based on the analysis of exhaled air.
First samples of Alcotesters appeared in the early of 1930s in USA and could only show the presence of alcohol in blood, but were not able to determine the amount. Regularly they were in use by police since 1939, but their capabilities came closer to capabilities of modern models only after a few decades.
The first "breathing tube" was patented by German company Dräger in 1953. For more than 60 years Dräger was engaged in this subject-matter and now it is a trendsetter, its instruments became standard of engineering solutions. The devices are widely used for monitoring the sobriety at enterprises with dangerous manufacture and for pre-trip inspections of drivers. The fact that alcotesters have the Certificate of the Ministry of Health means evidently that they may be used in medical practice. In order that alcotesters indications may testify in court as evidence, they should be completed with the entire set of authorizing documents, which are as follows: Certificate of compliance, Ministry of Health registration certificate, and the approval certificate about the type of instrument. The last document requires the availability of valid verification certificate.