Toxicology of Alcohol.

Measuring intoxication. Alcohol or ethyl alcohol is a colorless liquid. Alcohol or ethyl alcohol is a colorless liquid.

Degree of intoxication has many variables, so, Degree of intoxication has many variables, so, rapid and specific procedures for measuring the degree of intoxication were developed. Methodology based on spectrophotometry (breathalyzer) and chromatography (blood analysis).

Alcohol is a depressant Cerebral cortex, forebrain first then deeper into the cerebrum then rear portions of the brain. Cerebral cortex, forebrain first then deeper into the cerebrum then rear portions of the brain. High doses effect the medulla, which regulates vital functions such as respiration and heart activity. High doses effect the medulla, which regulates vital functions such as respiration and heart activity.

MRI’s show the effects of alcohol on the adult brain.

Deaths from alcohol consumption

Factors determining the rate of alcohol absorption. 1. Total time taken to consume a drink. 2. Alcohol content of the beverage 3. Amount consumed 4. Quantity and type of food in the stomach. Normally, minutes until absorption is complete.

Elimination of Alcohol. 2 mechanisms: 1. Oxidation 2. Excretion

Oxidation Alcohol Dehydrogenase Acetaldehyde Dehydrogenase Alcohol Dehydrogenase Acetaldehyde Dehydrogenase Alcohol  acetaldehyde  acetic acid  CO 2 + H 2 O  Any non-oxidized alcohol will be exhaled unchanged in the breath.  Amount of alcohol exhaled is directly proportional to the concentration in the blood.

Chronic alcohol consumption

Elimination Alcohol is eliminated in the breath, urine, sweat. Alcohol is eliminated in the breath, urine, sweat. Alcohol can be measured by: 1. Direct chemical analysis of the blood for its alcohol (gas chromatography) 2. Alcohol content of the breath. (breathalyzer)

Some Biology! Humans have a “closed circulatory system” Humans have a “closed circulatory system” - Heart, arteries, capillaries, veins.

Absorption of Alcohol Only 20% alcohol is absorbed in the stomach, the rest is absorbed in the small intestine. Only 20% alcohol is absorbed in the stomach, the rest is absorbed in the small intestine.

Alcohol and its metabolites in exhaled air. After passing through the circulatory system any alcohol and other volatile substances in the blood along with carbon dioxide  alveoli within the lungs  bronchial tubes  exhaled breath. After passing through the circulatory system any alcohol and other volatile substances in the blood along with carbon dioxide  alveoli within the lungs  bronchial tubes  exhaled breath.

Blood Test Blood alcohol : alcohol in exhaled breath Blood alcohol : alcohol in exhaled breath i.e. 1 mL : 2,100 mL i.e. 1 mL : 2,100 mL Venous blood is taken for the blood test. Venous blood is taken for the blood test. BUT, BUT, alcohol is not at the same concentration in different vessels in the body during the absorption phase.

Breath Test Reflect the concentration in the pulmonary artery. Reflect the concentration in the pulmonary artery. After absorption phase is complete, After absorption phase is complete, venous blood test = breath test, for the determined amount of alcohol in the system venous blood test = breath test, for the determined amount of alcohol in the system

Breathalyzer Collects 52.5mL of exhaled air (1/40 th of 2,100mL). Collects 52.5mL of exhaled air (1/40 th of 2,100mL). Potassium dichromate is oxidized by the alcohol  color change. Potassium dichromate is oxidized by the alcohol  color change. Silver nitrate is the catalyst. Silver nitrate is the catalyst.

Summary Summary Quantity of alcohol is measured indirectly by measuring the absorption of light by potassium dichromate before and after its reaction

Interfering substances and false positives Potassium dichromate: other alcohol groups could be oxidized too! false positives Potassium dichromate: other alcohol groups could be oxidized too! false positives Acetone Acetone Acetaldehyde Acetaldehyde Methanol Methanol Isopropyl alcohol Isopropyl alcohol Paraldehyde Paraldehyde Mouthwash, burping, breath freshener, acid reflux Mouthwash, burping, breath freshener, acid reflux

Components of IR breathalyzer.

Field Sobriety Tests 1. Psychological test - horizontal gaze nystamus - walk and turn (divided attention task) - one leg stand, reciting the alphabet backwards (divided attention task). 2. Preliminary breath test test

Analysis of Blood Alcohol levels. GC allows for the separation of alcohol as well as other volatiles. GC allows for the separation of alcohol as well as other volatiles. Compare retention times and peak areas to known blood-alcohol standards. Compare retention times and peak areas to known blood-alcohol standards.

Impairment versus blood alcohol.

Collection and preservation of blood. 1. A non-alcoholic disinfectant is applied. 2. Blood is drawn under medically accepted conditions by a qualified individual. 3. Blood is sealed in an airtight container with an anti- coagulant (EDTA, potassium oxalate) and a preservative (sodium fluoride).

Alcohol and the Law. Person >0.10 (% w/v) is considered under the influence in most States. Person >0.10 (% w/v) is considered under the influence in most States. Now 0.08 (% w/v) in NYS. Now 0.08 (% w/v) in NYS. Other countries and states can be lower: Other countries and states can be lower: 0.08% w/v - Canada, France, Italy, Switzerland, U.K. 0.05% w/v - Finland, Ireland, Japan, Netherlands, Norway. Netherlands, Norway.

“Implied Consent” Law Operation of a motor vehicle automatically carries with it the choice of either: 1. Submitting to a test for alcohol intoxication OR OR 2. Be subject to a loss of license for 6 months –1 year.