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Alcohol Impaired Driving

Alcohol Impaired Driving. Dr. Bruce A. Goldberger Professor and Director of Toxicology Departments of Pathology & Psychiatry University of Florida College of Medicine Gainesville, Florida. Toxicology - What is it?.

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Alcohol Impaired Driving

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  1. Alcohol Impaired Driving Dr. Bruce A. Goldberger Professor and Director of Toxicology Departments of Pathology & Psychiatry University of Florida College of Medicine Gainesville, Florida

  2. Toxicology - What is it? The study of the nature, effects, and detection of poisons and the treatment of poisoning. 3

  3. What is a Poison? Any substance that causes injury, illness, or death especially by chemical means. 4

  4. TOXICOLOGY in MedicineWhat is the Question ??? Document use, exposure, impairment, toxicity, cause of death, … 5

  5. “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)

  6. The Role of Alcohol in Traffic Accidents (Grand Rapids Study) Relative Probability of Causing an Accident

  7. Traffic Fatalities Source: NHTSA

  8. Impairment Florida Statutes Annotated Section 316.193 1(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.

  9. Overview • Introduction to ethanol • Effects of ethanol on driving • Pharmacology of ethanol • Pharmacology issues in DUI cases

  10. 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

  11. Units of Measure 0.08 g/dL 0.08 g/100 mL 0.08 gm% 0.08 % w/v 80 mg/dL (medical)

  12. 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”

  13. 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

  14. 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)

  15. 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?

  16. 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 Absorption

  17. Variables in Stomach Emptying • Food in stomach • Meal size/composition • Dose of alcohol • Beverage type • Anatomy of the gut; surgery • Time of dayempties faster in morning • Smoking (delays emptying) • GI motility • Drug use

  18. 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 Effect of Food on Blood Alcohol Concentration (BAC)? BAC Fasted Fed Time

  19. 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

  20. 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

  21. 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.

  22. Erik Widmark (1889-1945) First to describe blood alcohol relationship in quantitative terms: A = C P RA = DOSE of ethanolC = CONCENTRATIONP = WEIGHTR = % total body water R (men) = 0.51-0.86 R (women) = 0.47-0.64

  23. 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

  24. Average elimination:0.015 g/dL/h Range: 0.01 - 0.025 g/dL/h Relatively constant and independent of concentration Elimination

  25. 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

  26. 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

  27. 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

  28. Drug Impaired Driving

  29. Overview • Drug vs. Alcohol-related DUI • Effects of drugs other than alcohol • Documentation of drug effects • Interpretation of drug effects

  30. 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)

  31. 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 NHTSA

  32. 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 driving Source: NHTSA

  33. Drug Impaired Driving Drugs associated with impaired driving: • Cannabinoids/Marijuana • Depressants- Sedative/hypnotics, therapeutics, muscle relaxants, antidepressants, antihistamines • Stimulants- Cocaine, methamphetamine • Narcotic Analgesics- Morphine, codeine, hydrocodone, oxycodone, methadone

  34. Effect of Drugs on Driving

  35. Which Drugs Can Affect Driving? • Any drug that can affect the brain’s perception, collection, processing, storage or critical evaluation processes. • Any drug that affects communication of the brain’s commands to muscles or organ systems that execute them. • For the most part, drugs that affect the central nervous system (CNS).

  36. 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 language

  37. Effects of Drugs on Driving • CoordinationEffects 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

  38. Driving Domains Source: Barry Logan, Ph.D.

  39. Interpretation and Opinion of Impairment

  40. Interpretation Factors • Empirical Considerations • Epidemiological Studies • Case Reports • Laboratory Studies • Simulator Studies • On-the-Road Driving Studies

  41. 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

  43. 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

  44. Documentation of Drug Effects

  45. 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 information

  46. 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

  47. DRE Matrix

  48. Drug Signs

  49. 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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