Blood alcohol level

Clinical Analysis Clinical, pharmaceutical, and forensic labs make frequent use of gas chromatography for the analysis of drugs. Because the sample s matrix is often incompatible with the GC column, analytes generally must be isolated by extraction. Figure 12.25b shows how gas chromatography can be used in monitoring blood alcohol levels. 

Laws passed in some states define a drunk driver as one who drives with a blood alcohol level of 0.10% by mass or higher. The level of alcohol can be determined by titrating blood plasma with potassium dichromate according to the unbalanced equation... 

Most cases of mild to moderate intoxication with alcohol, as well as cases in which blood alcohol levels (BALs) are at the lower limits of legal intoxication (80 to 100 mg%, 0.08 to 0.1% or 17.4 to 21.7 mmol/L), do not require formal treatment. Such intoxications are characterized by mood lability, loud or inappropriate behavior, slurred speech, incoordination, or unsteady gait. 

M Frezza, C Di Padova, G Pozzato, M Terpin, E Baraona, CS Lieber. High blood alcohol levels in women the rold of decreased gastric alcohol dehydrogenase and first-pass metabolism. N Engl J Med 322 95-99, 1990. 

Table 9.2. Typical effects associated with rising blood alcohol levels.

Ethanol (EtOH, alcohol ) naturally occurs in fruit in small quantities. Alcoholic drinks contain much higher concentrations. Their alcohol content is usually given as percent by volume. To estimate alcohol uptake and the blood alcohol level, it is useful to convert the amount to grams of ethanol (density 0.79 kg L ). For example, a bottle of beer (0.5 L at 4% v/v alcohol) contains 20 mb = 16 g of ethanol, while a bottle of wine (0.7 L at 12% v/v alcohol) contains 84 ml = 66 g ethanol. 

Ethanol is membrane-permeable and is quickly resorbed. The maximum blood level is already reached within 60-90 min after drinking. The resorption rate depends on various conditions, however. An empty stomach, a warm drink (e.g., mulled wine), and the presence of sugar and carbonic acid (e.g., in champagne) promote ethanol resorption, whereas a heavy meal reduces it. Ethanol is rapidly distributed throughout the body. A large amount is taken up by the muscles and brain, but comparatively little by adipose tissue and bones. Roughly 70% of the body is accessible to alcohol. Complete resorption of the ethanol contained in one bottle of beer (16 g) by a person weighing 70 kg (distribution in 70 kg 70/100 = 49 kg) leads to a blood alcohol level of 0.33 per thousand (7.2 mM). The lethal concentration of alcohol is approximately 3.5 per thousand (76 mM). 

Chronic consumption of alcohol can result in a tolerance to its overt effects but it still affects functional ability, such as that required to drive a vehicle. Tolerance can develop to such an extent that an individual can have very high alcohol levels (300 to 400 mg/dl) and still not appear to be affected. However, the ability to tolerate high blood alcohol levels does not change the level necessary to produce death. 

Chronic excessive consumption of alcohol can result in physical dependence or alcoholism. There is often a steady progress in the need to drink, so that the person starts drinking early in the day to maintain blood alcohol levels and avoid withdrawal effects. Alcoholism often results in a variety of organ system effects, some of which are related to accompanying malnutrition. Treatment for alcoholism must address the withdrawal effects as well as associated vitamin deficiencies associated with malnutrition. 

Some of this difference in outcomes can be attributed to differences in metabolism—how the drug is absorbed, distributed in the body, chemically converted, and excreted. Thus two persons with the same body weight can consume the same number of drinks and have different blood alcohol levels two hours later. For more subtle and less known reasons, the effectiveness of the drug in creating its effects and in reinforcing drug-taking behavior also varies. 

Georges, William R, and John C. Lawn. Battling Hardcore Drunk Driving. Police Chief, July 1999, pp. 47-50. Reports on efforts to combat hardcore drunk driving, defined as offenders caught repeatedly with high blood alcohol levels. The authors believe that effectively deterring... 

Ross, L.E. and Mundt, J.C., Multiattribute modeling analysis of the effects of low blood alcohol level on pilot performance, Hum. Factors, 30, 293, 1988. 

What is the blood alcohol level in mass percent if 8.76 mL of 0.049 88 M K2Cr207 is required for titration of a 10.002 g sample of blood ... 

As with most drugs that affect your brain, the rate at which your blood alcohol levels rise also affect your behavior—that is, faster changes in blood alcohol levels produce more dramatic effects on your behavior. As alcohol levels increase, more and more of your brain is turned off by alcohol s enhancement of GABA. Ultimately, when blood levels become too high, neurons critical to controlling your breathing and heart rate are inactivated... 

Poisoning may be characterized by inebriation, muscular incoordination, blurred vision, impaired reaction time, excitement due to loss of inhibitions, impairment of consciousness, coma, tachycardia, and slow respiration. A blood alcohol level of 80 mg/dl can produce recognizable features of drunkenness a level above 300 mg/dl is life threatening. In children, severe hypoglycemia and convulsions may also occur. 

United States Congress passes transportation spending bill including establishment of a national standard for drunk driving for adults at a 0.08% blood alcohol level (BAL). States are required to adopt this stricter standard by 2004 or face penalties. By 2001, more than half the states adopt this stricter standard. 

Alcohol and Car Driving The effects of alcohol and driving are a subject of great importance, as many countries have made laws designed to prevent car accidents. Accidents involving alcohol number as many as 50% of total accidents (Fig. 14-1). Hence, it is necessary to perform breath or blood tests to determine a driver s alcohol content. In the United Kingdom, a blood-alcohol level exceeding 80 mg/100 mL is an offense other countries such as the United States and Australia have lower limits. 

A 45-year-old man who has been injured in a car accident is brought into the emergency room. His blood alcohol level on admission is 275 mg/dL. Hospital records show a prior hospitalization for alcohol related seizures. His wife confirms that he has been drinking heavily for 3 weeks. What treatment should be provided to the patient if he goes into withdrawal ... 

ADH activity and to enhance the bioavailability of ethanol, with a resulting increase in blood ethanol levels. This exaggeration by certain drugs is particularly important for social drinkers, who commonly take several small drinks, but experience a cumulative effect on blood alcohol levels. 

When considering the issnes of alcohol tolerance and withdrawal, it is usefnl to review what is expected for the normal person in response to varions blood alcohol levels (BALs) ... 

Tolerance may occur to the point that patients can appear to be alert and talking coherently with blood alcohol levels in excess of 400 mg/dl, but these individuals are still at risk of respiratory arrest and death at that level of intoxication. Later, they will not remember what occurred during this time (they are in a blackout), and they may experience alcohol withdrawal symptoms when their BAL drops from 400 to 200, a level that is still indicative of intoxication for most people. 

However, on the basis of past experience I am confident that they all can be sung, provided that certain rules are followed. Firstly, the scansion must be worked over privately, as some words and phrases have to be accented at surprising places. Secondly, these are songs they should not be declaimed as poems. Thirdly, they are intended for communal singing, preferably with musical accompaniment and ideally with a blood alcohol level of around 35 mg per cent. 

DiPadova C, Roine R, Frezza M, Gentry RT, Baraona E, Lieber CS. Effects of ranitidine on blood alcohol levels after ethanol ingestion. Comparison with other H2-receptor antagonists. JAMA 1992 267 83-6. Erratum in JAMA 1992 268 2652. 

A forensic laboratory analyses blood samples from drivers suspected of driving under the influence of alcohol. The legal blood alcohol level for driving is 80 mg of alcohol in 100 mL of blood (80 mg%). The method used to analyse the blood samples will have been thoroughly validated at this concentration, to determine its accuracy and precision so as to ensure that innocent drivers are not found guilty, etc. If a lower limit of 50 mg% is introduced then the method will have to be validated at this lower concentration. 

The stronger the drink, the faster the blood alcohol level will rise and the sooner a person will get drunk. Gulping down cocktails and drinking wine like water are good ways to speed through the more pleasant, early effects of alcohol intoxication and go right to the less desirable ones. 

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