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Set of flashcards Details
| Flashcards | 29 |
|---|---|
| Language | English |
| Category | Chemistry |
| Level | University |
| Created / Updated | 13.01.2016 / 07.02.2016 |
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What 4 common types of cases or circumstances is forensic alcohol toxicology used in? (4p)
1. Sexual assault
2. Impaired driving
3. Assault or homicide
4. Coroner's death investigation
About 14g of alcohol is in these 3 common, "measurements" of drinks... (3p)
1. One shot (40% alc v/v, 1.5fl. oz or 43mL)
2. One glass of wine (12% alc v/v, 5fl. oz, 142mL)
3. One regular bottle of beer (5% alcohol, 12fl. oz, 341mL)
What are the 3 main focuses in pharmocokinetics, in the view of forensic toxicology? (3p)
1. Absorption
2. Diffusion
3. Metabolism or elimination
What are the 2 main focuses in pharmacodynamics, in the view of forensic toxicology? (2p)
1. Drug effects
2. Drug interactions
How is the [drug] in the blood related to the [drug] in the tissue? What does this infer? (2p)
1. [Drug]blood <--> [Drug]tissue
2. Alcohol level in blood = alcohol level in brain
What are 4 factors affecting [Drug]blood? (4p)
1. Dosage
2. Rate of "infusion"
3. Rate of metabolic break-down of a drug
4. Time since ingestion
What are 4 factors affecting ethanol absorption (by oral administration)? (4p)
1. The presence of food
2. Alcohol concentration in beverage consumed (rate minimal ~20% alcohol v/v)
3. Dosage (eg. number of drinks)
4. Rate of ingestion (eg. funnels vs social drinking)
Explain what distribution is under the context of alcohol pharmacology, and how it distributes in the two sexes. (3p)
Distribution: the delivery of ethanol to various tissues and dilutions within the circulatory system
1. Men = ~70% water content by weight
2. Women = ~60% water content by weight
Explain the process of elimination for alcohol. (4p)
1. Alcohol is metabolized primarily in the liver
2. Undergoes oxidation the acetaldehyde
3. Undergets oxidation from acetaldehyde to acetic acid
4. Breaks down into CO2 and H2O
What is an important attribute in alcohol dehydrogenase (ADH), the primary biotransformation enzyme for alcohol metabolism? (2p)
1. ADH is constitutive (non-inducible)
2. Inducible metabolic enzyme systems become important to ethanol metabolism at higher BACs, in excess of 100mg/100mL
What is the percentage breakdown for the metabolization of ethanol in the body? (4p)
95% metabolized in the liver
1-2% unchanged in urine
1-2% unchanged in the breath
Traces unchanged in sweat, tears, etc.
At what kind of rate is ethanol eliminated at? What is the forensically relevant concentration window? (2p)
1. Ethanol is eliminated at a constant rate
2. The forensically relevant concentration window is >20mg / 100mL
What is the elimination rate of the general population? In light to moderate drinkers?(1p)
1. Rate = ~10-25mg/100mL per hour, but includes heavier drinkers.
2. Upper limit is for light to moderate drinkers is considered to be ~20mg/100mL per hour
In what shape is the elimination rate observed in a graph? (1p)
Linear alcohol is eliminated at a constant rate
In three main stages, explain the effects of alcohol on the body according to BACs. (3p)
1. Relatively low BACS --> loss of information processing and judgement
2. At higher BACs --> loss of motor function
3. At very elevated BACs --> basic brain functions --> possible coma, respiratory depression, death, etc.
What 3 facts in pharmocodynamics is important in understanding forensic alcohol toxicology? (3p)
1. Alcohol is a central nervous system (CNS) depressant
2. Alcohol effects are dose-dependent
3. Correlations between estimated BACs and the degree of impairment are often requested by the court
Define the frequency of use in alcohol-drinking, in four categories. (4p)
1. Light drinker (<1 drink/day)
2. Moderate drinker (~1-2 drinks/day)
3. Heavy drinker (~3-4 drinks/day)
4. Abusive drinker (>5 drinks/day)
Describe the effects of the 7 ranges of BAC, and the effects that one has (as part of the general population - without special toleration)
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What four things may vasodilation lead to? (4p)
1. Reduced blood pressure
2. Increased blood rate (to alow ealthy blood flow in the dilated vessels)
3. Muscle fatigue
4. Hypothermia (potentially fatal, even in summer months)
What are the effects of alcohol on aggression? (2p)
1. Alcohol does not cause aggressive behaviour, but through disinhibitory effects, facilitates behaviour that may otherwise have been kept under control
2. Cannot lead to automatism as one will pass out before the effect is possible
What are 6 sensitive faculties necessary for driving that are affected by alcohol intake? (6p)
1. Divided attention
2. Choice reaction time
3. Judgement (risk, hazard, speed, distance)
4. Tracking (eg. steering)
5. Vigilance (concentrated attention)
6. At progressively higher BACs, visual and auditory effects, along with coordination, become increasingly impaired
What are 3 types of methods used to analyze ethanol in forensic applications? (3p)
1. Chromatographic methods
2. Enzymatic methods
3. Headspace methods
Describe the procedure of headspace methods (4p)
1. Sample of blood (~0.5mL) is placed into ~20mL vial and hermetically sealed
2. Samples are heated (~40°C)
3. Ehtanol in sample undergoes equilibrium partitioning between blood and the air above (headspace)
4. A sample of the headspace is injected into a gas chromatography (GC)
How is the ethanol detected after being separated through gas chromatography? How accurate is the ethanol analysis by these methods? (3p)
1. Ethanol is detected by flame ionization detection (FID) which analyzes the mass spectra for each target compound
2. Ethanol analysis by these methods are typically very accurate and precise (accuracy often within 5-10% of actual values, with precision also on that order)
3. BACs measured may be used to estimate toxicity well
Sinc alcohol is a relatively volatile drug (BP = 73°C), how can we use Henry's Law to analyze ethanol in breath? (2p)
1. A volatile substance in solution (eg. ethanol in blood) will achieve, at equilibrium such that the concentration i nthe vapour will be proportional to the concetration in solution, under conditions of constant temperature and pressure
2. EtOHvapour <--> EtOHsolution
What is deep lung air? (1p)
Deep lung air: the last 1/3rd of expired air following a deep breath in
Within how many hours is a breath test considered accurate of the time of driving while drunk? (1p)
Within 2hrs of the time driving while drunk counts as being the same as when the person was driving
What is the Blood-Breath ratio (BBR) as described by Henry's law? What are the true BBR averages and how are the evidentiary instruments used in Ontario calibrated? (3p)
1. BBR = CEtOH(Blood) / CEtOH(breath)
2. The true BBR averages are ~2350-2450
3. The evidentiary instruments used in Onario are calibrated to use a BBR of 2100-1
What is the 2 differences between the Intoxilyzer 5000C and Intoxilyzer 8000C? Define the law used (3p)
1. The sample of breath is introduced into a chamber sample where it is exposed to IR radiation at:
- 3 different wavelengths (3.39, 3.48, and 3.80µm) for the Intoxilyzer 5000C
- 2 different wavelengths (3.4 and 9µm) for the Intoxilyzer 8000C
2. The absorbance (A) of IR radiation at
- 3.39µm for Intoxilyzer 5000C is proportional to ethanol concentration (c) according to Beer's law
- 3.4µm for Intoxilyzer 8000C is proportional to ethanol concentration (c) according to Beer's law
A = εbc
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