alcohol impaired driving

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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.