Info

Coma

Complete unconsciousness; coma; anesthesia. Depressed or abolished reflexes. Subnormal temperature. Incontinence of urine and feces. Impairment of circulation and respiration. Possible death.

0.45+

Death

Death from respiratory arrest.

*Reprinted by permission from KM Dubowsky. Copyright 19S7, (2).

*Reprinted by permission from KM Dubowsky. Copyright 19S7, (2).

Biochemical effects:

Hyponatremia and hypochloremia are common in the chronic alcoholic (3). Hyperlipidemia also may be found.

What is the Legal Interpretation of Alcohol (Ethanol) Intoxication?

Objective impairment of driving ability is observed at threshold blood alcohol concentrations of 35-40 mg/dL. However, values less than 50 mg/dL are considered evidence of "not under the influence" by courts in most states. Values greater than 150 mg/dL are prima facie evidence of "under the influence"; most persons are obviously intoxicated in this range. In 1971 the National Safety Council Committee of Alcohol and Drugs released the following statement: "The National Safety Council Committee on Alcohol and Drugs takes the position that a concentration of 80 milligrams of ethanol per 100 milliliters of whole blood (0.08% w/v) in any driver of a motor vehicle is indicative of impairment in his driving performance."

Can Postmortem Changes and Specimen

Storage Affect Blood Alcohol (Ethanol) Concentrations?

Blood alcohol concentrations obtained at autopsy are valid until putrefaction begins. This may vary from several hours to a few days, depending on the environment. Sodium fluoride in a concentration of 10 mg/mL of blood should be added to the sample, and the specimen should be stored in the refrigerator. If the blood is analyzed soon after withdrawal or if the blood is kept in the refrigerator, results are usually reliable even if no sodium fluoride has been added. If the air space above the blood samples in the container is large, alcohol can evaporate and a falsely low blood alcohol level can result. Putrefactive changes before autopsy or during storage may cause a falsely high blood alcohol concentration. Ethanol can be produced in the specimen container; this is more like in the absence of a preservative. Because fluoride inhibits bacteria far more than fungi, higher fluoride concentrations are required for the inhibition of fungal growth (4).

Can the Sites Where Blood Was Withdrawn Affect Alcohol (Ethanol) Concentrations?

Although there is no major difference in the alcohol concentrations of blood samples from the intact heart chambers and the femoral vessels (5), autopsy samples from pooled blood in the pericardial sac or pleural cavity are unsatisfactory. We therefore recommend that blood be withdrawn from peripheral vessels.

Is There Normal "Endogenous"

Blood Alcohol (Ethanol) in a Living Person?

Blood alcohol concentrations are generally believed to be negligible in the absence of ingested alcohol. "Endogenous" ethanol in human blood exists at a concentration of about 0.0002 g/dL, which is below the limit of detection for most methods (6).

Which Conditions or Factors May Lower the Tolerance to Alcohol (Ethanol) So That Death

May Occur at Levels That Are Not Usually Fatal?

First in such a list would be postural asphyxia, for example, in drunks who fall asleep face down. Also, depressant drugs in the tricyclic, analgesic, barbiturate, and benzodiazepine classes all potentiate the effect of alcohol (7). Also included in such a list would be infancy and childhood; ischemic heart disease;* chronic bronchitis and emphysema;* other chronic debilitating diseases; poisoning with carbon tetrachloride* or carbon monoxide;* and other causes of hypoxia.*

How Can One Estimate Blood Alcohol (Ethanol) Concentrations From Vitreous, Urine, or Tissue Alcohol Levels and From Alcohol in Stomach Contents?

The ratio of serum, plasma, urine, vitreous, and various tissues has been compiled by Garriot (8). The values may vary considerably. For vitreous, the ratios varied from 0.46-1.40. These variations may depend on whether blood alcohol concentrations were increasing or decreasing at the time of death. Most other body fluids and tissues showed ranges closer to 1. Most urine values were above the blood alcohol concentrations. In another study (9), the blood/vitreous (B/V) ratio in the early absorption phase was 1.29 (range, 0.71-3.71; SD 0.57) and in the late absorption and elimination phase, the B/V ratio was 0.89 (range, 0.32-1.28; SD 0.19). Blood ethanol concentrations probably can be estimated using B = 1.29 V for early absorption and B = 0.89V for later phases. A urine/blood ethanol ratio of 1.20 or less indicates that the diceased was in the early absorption phase.

How Can One Use Alcohol (Ethanol) Concentrations in Postmortem Specimens To Estimate the Blood Alcohol Concentration at Various Times Before Death?

With certain limitations, one can base calculations of this kind on the assumption that the blood alcohol level decreases from its peak at a fairly constant rate of 0.015-0.018/h until death (10). If blood is not available, conversion factors (see above) must be used. Alcoholics have been reported to metabolize at a rate of up to 0.043%/h (6).

Example: The driver of an automobile had been drinking at a party until midnight. He had left his host at about 1:30 a.m. and was involved in a head-on collision at 2:15 a.m. He died in the emergency room of the hospital at 6:35 a.m. There were multiple injuries and the patient had exsanguinated. The autopsy was done at 1:30 p.m. Although this appears quite unlikely, let us assume that no satisfactory blood sample was obtained and that no blood or plasma expanders were given. If under such circumstances the alcohol concentration in the vitreous was found to be 157 mg/dL, what was the alcohol concentration in the blood at the time of the accident?

Vitreous and blood alcohol concentrations may be assumed to have remained unchanged after death. Therefore, the blood alcohol level at the time of death must have been approx 157 (vitreous humor alcohol) x 0.89 (conversion factor, see above) = 140 mg/dl. The time interval between the accident (2:15 a.m.) and death (6:35 a.m.) was 4 h and 20 min or 4 1/3 h. If we assume that the decedent was not an alcoholic and that the blood alcohol concentration was decreasing from its peak at a constant rate of 15 mg/dL/h, then the concentration at the time of the accident is estimated to have been 140 (concentration at time of death) + (4 1/3 x 15) = 140 + 65 = 205 mg/dL or 0.2%.

The blood alcohol concentration at the time of the accident could have been lower if the victim stopped drinking later than 1 h or 1 1/2 h before the accident. In the latter case, the peak alcohol level would have occurred after the accident, reflecting the time to absorb the latest drink.

The blood alcohol concentration at the time of the accident could have been lower or higher if the time when the patient stopped drinking, the time of the accident, or the time of the death is uncertain.

The blood alcohol concentration at the time of the accident could have been higher if the victim was a chronic alcoholic (based on the history or the presence of alcoholic hepatitis or alcoholic cirrhosis). The elimination rate in such persons may be as high as 40 mg/dL, which would change the figures in our example above to 140 + (4 1/3 x 40) = 140 + 173 = 313 mg/dl or 0.3%.

How Can One Use Alcohol (Ethanol) Concentrations in Postmortem Specimens To Estimate How Much the Victim Had Been Drinking?

Only rough estimates are possible. First, the peak blood alcohol level must be determined or calculated, as described in the previous paragraphs. Tables (see below) are available that relate blood alcohol level to the minimal amounts of whiskey, wine, or beer that must have been consumed (10). However, tables of this type are often based on the minimum amount of alcohol circulating in the body after specific numbers of drinks; such tables do not yield reliable results if used conversely. Furthermore, inasmuch as drinking and elimination of alcohol may take place concomitantly, over a longer period the total amount of alcohol consumed may have been much greater than the tables would indicate. It cannot be lower. According to these tables, 6 pints of ordinary beer or 8 fl oz of whiskey would be the minimal amounts needed to produce a blood alcohol level of about 200 mg/dL in a person weighing 140-180 pounds. The total body alcohol can be calculated from the blood alcohol level by using Widmark's formula:

Average concentration of alcohol in entire body = .68 Concentration of alcohol in the blood

In a person weighing 70 kg, the blood alcohol concentration would be increased 50 mg/dL (0.05%) by the absorption of 1 oz of ethanol (2 oz of 100-proof whiskey).

What Is the Alcohol

(Ethanol) Content of Various Beverages?

Strength of alcohol is measured in "proof'; absolute alcohol is 200 proof. Therefore, in the United States, alcohol content as volume percent is half the proof (for example, 100-proof whiskey contains 50% alcohol by volume). The alcohol content of various beverages is shown in the following table.

Approximate Alcohol Content in Various Beverages^

Beverage

Ethanol Content in %

Whiskey and gin Brandy

Sherry and port wines

Liqueurs

Beers (Lager) Light wines

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