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Alcohol Impaired DrivingDr. Bruce A. Goldberger
Professor and Director of ToxicologyDepartments of Pathology & Psychiatry
University of Florida College of MedicineGainesville, Florida
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Toxicology - What is it?
The study of the nature, effects, and detection of poisons and the
treatment of poisoning.
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What is a Poison?
Any substance that causes injury, illness, or death
especially by chemical means.
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TOXICOLOGY in MedicineWhat is the Question ???
Document use, exposure, impairment, toxicity, cause of death, …
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“What is there that is not poison? All things are poison and nothing without poison. Solely the dose determines that a thing is not a poison.”
– Paracelsus (1493-1541)
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The Role of Alcohol in Traffic Accidents
(Grand Rapids Study)
Relative Probability of Causing an Accident
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Traffic Fatalities
Source: NHTSA
ImpairmentFlorida Statutes Annotated Section 316.1931(a) …The person is under the influence of … any chemical substance…or any controlled substance…, when affected to the extent that the person's normal faculties are impaired.
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Overview Introduction to ethanol Effects of ethanol on driving Pharmacology of ethanol Pharmacology issues in DUI cases
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Introduction Ethanol is a dose-dependent
depressant drug Social Lubricant -
Effects include loss of inhibitions, altered judgment, relaxation, increased confidence, expansiveness, vivacious personality, loquaciousness
Depressant Effects -Slurred speech, ataxia, sedation, stupor, coma, death
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Units of Measure
0.08 g/dL0.08 g/100 mL0.08 gm% 0.08 % w/v80 mg/dL (medical)
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Effect of Alcohol- Central Nervous System -
Continuum of depression, not discrete effects Low BAC - apparent stimulant effect (depression
of inhibitory processes) Increasing BAC: judgment, decision-making,
perception, reaction time are impaired. Impairment develops prior to overt signs of
intoxication, ataxia, slurring, loss of balance Mental/physical abilities diminished well before
the appearance of a “classic drunk”
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Stages of Alcohol Intoxication- Dubowski -
• Subclinical <0.05 g/dL• Euphoria 0.03 - 0.12 g/dL• Excitement 0.09 - 0.25 g/dL• Confusion 0.18 - 0.30 g/dL• Stupor 0.25 - 0.40 g/dL • Coma 0.35 - 0.50 g/dL Death >0.45 g/dL
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Why 0.08? – The SCIENCE
Virtually all drivers, including experienced drinkers are impaired at a
BAC of 0.08 (based on a review of hundreds of scientific studies)
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Common Issues in DUI case? Time to peak blood alcohol concentration ? Validity of a rising BAC defense? Is the drinking history (amount/time) consistent
with the BAC? How many drinks did it take to reach the
measured BAC? What was the BAC at the time of driving/crash
as opposed to the time of testing? How does alcohol affect driving? Tolerance?
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Absorption Controlled by diffusion Absorption at each site
depends on quantity of alcohol, time in contact, vascularity and surface area
Small intestine/duodenum (large surface area)
Absorption is affected by gastric emptying
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Variables in Stomach Emptying Food in stomach Meal size/composition Dose of alcohol Beverage type Anatomy of the gut; surgery Time of day
empties faster in morning Smoking (delays emptying) GI motility Drug use
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Effect of Food on Blood Alcohol Concentration (BAC)?
• Empty Stomach• Peak BAC occurs
earlier• Magnitude of BAC
is higher
• Food in stomach• Food competes
with ethanol for sites in the small intestine, slows absorption
• Lower peak BAC• Diminished
feelings of intoxication
• Shorter time to zero BAC
BAC
Time
Fed
Fasted
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Blood Alcohol Curve- Time to Peak BAC -
Single dose, empty stomach, peak BAC in 1hr in most individuals
Social drinking situation, multiple drinks over several hours, peak BAC typically within 30 min of last drink
Distribution Alcohol distributes throughout body Distributes according to water content Increased water content, increased alcohol
content Percentage of total body water (Widmark)
Men approximately 70%Women approximately 55%
- alcohol distributes in smaller volume in women, higher BAC
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A standard drink contains:
1 fluid ounce of 100 proof ethanol or
½ fluid ounce of pure ethanol
100 proof distilled spirits: 1 fl. oz.wine: 3-4 fl. oz.beer: 12 fl. oz.
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Erik Widmark (1889-1945)
First to describe blood alcohol relationship in quantitative terms: A = C P R
A = DOSE of ethanolC = CONCENTRATIONP = WEIGHTR = % total body water
R (men) = 0.51-0.86R (women) = 0.47-0.64
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Utility of the Widmark Equation
· You may estimate a DOSE of ethanol from a BAC
· You may estimate a BAC from a DOSE· This may be significant in DUI cases to
corroborate/disprove drinking history· Some assumptions are necessary· Assumptions need to be clearly stated by
the expert
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Elimination· Average elimination:
0.015 g/dL/h· Range: 0.01 - 0.025 g/dL/h· Relatively constant and independent
of concentration
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Retrograde Extrapolation Allows estimation of the
theoretical BAC in the linear (post absorptive phase)
Requires multiple assumptions Range of elimination rates
to cover population variations 0.01 - 0.02 g/dL/h
Alcoholics up to 0.035 g/dL/h Liver dysfunction 0.009 g/dL/h
BAC
Time
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Tolerance Larger dose needed to achieve desired response Acute tolerance (Mellanby Effect)
Effects of alcohol are perceived to be greater when BAC is ascending, rather than descending
Chronic tolerance (Develops over time)Tolerance lost within 5-7 days of abstinence
Kinetic: faster metabolism Dynamic: Emetic and sedative effects Experience: adaptation, speaks slowly, hold on
to chair, etc. to appear less intoxicated
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Summary Alcohol produces a continuum of effects,
rather than discrete effects Interpretation of DUI cases may involve
expert testimony Alcohol pharmacology plays an important
role Calculations may be subject to certain
assumptions or generalizations All assumptions need to be clearly stated by
the expert
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Drug Impaired Driving
Overview Drug vs. Alcohol-related DUI Effects of drugs other than alcohol Documentation of drug effects Interpretation of drug effects
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Two general approaches…. May require the driver to
be “affected by” May require the drug to
impair a driver’s ability to operate a vehicle safely, incapable of driving safely or require a driver to be under the influence, impaired or affected by an intoxicating drug
Per-se or zero tolerance drug laws
Make it a criminal offense to have a specified drug or metabolite in the body while operating a motor vehicle
Any amount (zero tolerance) or a specified level (per se)
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Drug Impaired Driving- National -
More difficult to prosecute than alcohol-impaired driving
Under-reported, under-recognized Drugs are constant factor in traffic crashes Full impact relatively unknown 9 million people drive after using drugs Drugs (other than alcohol) found in 17.8%
fatally injured drivers
Source: DHHS and NHTSA32
Drug Impaired Driving- National -
Drugs detected in 10 to 22% of drivers involved in crashes, often in combination with alcohol
Drugs detected in up to 40% of injured drivers requiring medical treatment
Drug use among drivers arrested for motor vehicle offenses is 15-50%
Highest rates reported among those arrested for impaired or reckless drivingSource: NHTSA
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Drug Impaired DrivingDrugs associated with impaired driving: Cannabinoids/Marijuana Depressants
- Sedative/hypnotics, therapeutics, muscle relaxants, antidepressants, antihistamines
Stimulants- Cocaine, methamphetamine
Narcotic Analgesics- Morphine, codeine, hydrocodone, oxycodone,
methadone34
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Effect of Drugson Driving
Which Drugs Can Affect Driving?1. Any drug that can affect the brain’s
perception, collection, processing, storage or critical evaluation processes.
2. Any drug that affects communication of the brain’s commands to muscles or organ systems that execute them.
3. For the most part, drugs that affect the central nervous system (CNS).
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Drug Impairment Issues· More complex than alcohol· Often in combination with other drugs
and/or alcohol (additive or synergistic effects)
· Scientific literature is complex· May require a toxicologist to interpret the
results and provide an opinion· These complex issues must be explained to
the court using every day language37
Effects of Drugs on Driving Coordination
Effects on nerves/muscles - steering, braking, accelerating, manipulation of vehicle
Reaction TimeInsufficient response
JudgmentCognitive effects, risk reduction, avoidance of potential hazards, anticipation, risk-taking behavior, inattention, decreased fear, exhilaration, loss of control
TrackingStaying in lane, maintaining distance
AttentionDivided, not focused. Time-shared task with high demand for info processing
Perception90% of info processed while driving is visual. Glare resistance, recovery, dark and light adaptation, dynamic visual acuity
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Driving DomainsSensory/Perceptual
Alertness Arousal
Attention Processing Speed
Executive Functioning
Reaction Time Psychomotor Functioning
39Source: Barry Logan, Ph.D.
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Interpretation and Opinion of Impairment
Interpretation Factors Empirical Considerations Epidemiological Studies Case Reports Laboratory Studies Simulator Studies On-the-Road Driving Studies
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What is the Basis for the Opinion of Impairment?
Impairment is based on knowledge of the drug(s), intended effects, side effects and toxic effects
The toxicologist can rarely give an opinion based upon the drug report alone
The opinion may depend on the context of the case and information gathered by the investigator (situation, environment, observations, performance on FSTs, driving pattern, etc.) 42
What the Toxicologist cannot do….
· Determine impairment in a specific individual from a drug concentration alone
· Determine exactly how much drug was taken
· Determine exactly when a drug was taken
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Drug Interpretation Issues Multiple drug use Tolerance History of drug use (chronic vs. naïve) Health Metabolism Genetic/Ethnic differences Individual sensitivity/response Withdrawal Put in context of case
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Documentation of Drug Effects
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Recognition of the Drug-Impaired Driver
First Choice: DRE Certification Systematic, standardized, post-arrest procedure for
Drug Evaluation and Classification (DEC) DEC Certified officers are Drug Recognition Experts 12-step evaluation of behavior, appearance,
psychophysical tests, vital signs, eye measurements DRE documents drug signs and symptoms. These are
interpreted by a Toxicologist in a DUID case DRE cases provide the court with additional
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Recognition of the Drug-Impaired Driver
Non-DRE Officer Documentation of signs/symptoms in police
report Toxicologist can use the signs/symptoms to
determine whether impairment was due to drugs
The toxicologist needs information from many sources to render an opinion of impairment
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DRE MatrixIndicators consistent with Drug Categories
Depressants Stimulants Hallucinogens PCP Narcotics Inhalants Cannabis
HGN Present None None Present None Present None
Vertical Nystagmus
Present (High dose) None None Present None Present
(High dose) None
Lack of Convergence Present None None Present None Present Present
Pupil Size Normal1 Dilated Dilated Normal Constricted Normal4 Dilated6
Reaction to light Slow Slow Normal3 Normal Little or
none visible Slow Normal
Pulse Rate Down2 Up Up Up Down Up Up
Blood Pressure Down Up Up Up Down Up/Down5 Up
Body Temperature Normal Up Up Up Down Up/Down
Normal Normal
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Drug Signs
Signs and Symptoms:Depressants
Confusion Poor divided attention Sedation Droopy eyelids Slowed reaction times Memory effects HGN
Poor balance Poor coordination Unsteadiness Slurred speech Disorientation Low b.p. Low pulse
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Signs and Symptoms:Stimulants
Hypervigilant Excitability Anxious Self absorbed Agitated Paranoid Delusional Obsessive activity
Rapid speech Thought blending Tremors Hand wringing jaw clenching Dilated pupils Elevated b.p. Elevated pulse
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Signs and Symptoms:Stimulant Withdrawal
Hypersomnolence Fatigue Exhaustion Withdrawal Agitated Paranoia Delusions Tremors Chills
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Stimulant withdrawal can mimic depressant effects
Signs and Symptoms:Marijuana
Relaxed Sedation Confused Poor divided
attention Memory effects
Poor balance Poor coordination Reddening of eyes Eyelid tremors Elevated pulse Elevated b.p.
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Signs and Symptoms:Opiates
Euphoria Sedation Confusion Stupor Droopy eyelids Slowed reaction times
Slowed reflexes Poor balance Poor coordination Constricted pupils Low pulse Low b.p.
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Driving Behavior- Depressants -
· Weaving· Extreme lane of travel· Striking other vehicles· Striking fixed objects· Slow speed· Hit and run· Wrong way driving
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Driving Behavior- Stimulants -
· Drive-off-the road accidents· Leaving lane of travel· Speeding· High speed collisions· Erratic or risky driving
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Recent Trends in Florida· Marijuana· Xanax· Methamphetamine· Inhalants -
Difluoroethane (Dust-off)
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Is The Driver Impaired?
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Positive ToxicologyDrugs in Urine
· Good specimen to screen for large number of drugs
· Typically see metabolites · Indicates drug use within the past 2-3 days
or more· Cannot definitively establish impairment· “Consistent with” or “Explanation for” the
impairment59
Positive ToxicologyDrugs in Blood
· If in the blood, assumed to be affecting CNS and other target organs
· Typically see parent compounds (or both)· Quantitation
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Thank You!
Acknowledgement:
Many slides were provided by Dr. Sarah Kerrigan.