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Drug Impaired Driving Dwain C. Fuller, D-FTCB, TC-NRCC Technical Director of Toxicology, VANTHCS Private Practice Forensic Toxicology Consultant [email protected] Traffic Safety Initiative Conference, Austin, Texas April 2014 Overview Types of Toxicology Human Performance Toxicology Laboratory Testing Interpretation Challenges Limitations New Drugs Copyright 2014, Dwain C. Fuller, D-FTCB Forensic Toxicology Forensic Urine Drug Testing Postmortem Forensic Toxicology Human Performance Toxicology Copyright 2014, Dwain C. Fuller, D-FTCB Drugs and poisons in human biological specimens with legal implications. Three sub-disciplines:

Drug Impaired Driving

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Drug Impaired Driving

Dwain C. Fuller, D-FTCB, TC-NRCCTechnical Director of Toxicology, VANTHCSPrivate Practice Forensic Toxicology [email protected]

Traffic Safety Initiative Conference, Austin, TexasApril 2014

Overview

Types of Toxicology

Human Performance Toxicology

Laboratory Testing

Interpretation Challenges

Limitations

New Drugs

Copyright 2014, Dwain C. Fuller, D-FTCB

Forensic Toxicology

Forensic Urine Drug Testing

Postmortem Forensic Toxicology

Human Performance Toxicology

Copyright 2014, Dwain C. Fuller, D-FTCB

Drugs and poisons in human biological specimens with legal implications.

Three sub-disciplines:

Forensic Toxicology

Forensic Urine Drug Testing

Postmortem Forensic Toxicology

Human Performance Toxicology

Copyright 2014, Dwain C. Fuller, D-FTCB

Drugs and poisons in human biological specimens with legal implications.

Three sub-disciplines:

Forensic Toxicology

Forensic Urine Drug Testing

Postmortem Forensic Toxicology

Human Performance Toxicology

Copyright 2014, Dwain C. Fuller, D-FTCB

Drugs and poisons in human biological specimens with legal implications.

Three sub-disciplines:

Forensic Toxicology

Forensic Urine Drug Testing

Postmortem Forensic Toxicology

Human Performance Toxicology

Copyright 2014, Dwain C. Fuller, D-FTCB

Drugs and poisons in human biological specimens with legal implications.

Three sub-disciplines:

Human Performance Toxicology

Effects of drugs on living humans

Performance of what? Driving

Walking

Making judgments

Drug Facilitated Sexual Assault

Other

Copyright 2014, Dwain C. Fuller, D-FTCB

The Role of the Toxicologist

Testing Alcohol

Drugs

Other intoxicants

Interpretation Substance

Concentration

Context

Other factors

Testimony

Copyright 2014, Dwain C. Fuller, D-FTCB

Testing - Alcohol

Usually dual column gas chromatography-flame ionization-headspace Identifies analytes by differing retention times on two different

chromatographic columns

Well-established and specific

Sometimes enzymatic analysis (hospital specimens) Doesn’t directly measure ethanol

Measures an enzyme/substrate/cofactor reaction

May produce false or elevated results under certain conditions

Rarely gas chromatography/mass spectrometry (GC/MS) Highly defensible

Probably “overkill”

Copyright 2014, Dwain C. Fuller, D-FTCB

Testing - Drugs

Two step process Screening Typically “immunoassay” Based on antibody-antigen reactions Non-specific Limited in scope Must meet threshold requirement Not forensically defensible without confirmation

Confirmation/Quantitation Typically mass spectrometric (GC/MS, LC/MS, LC/MS/MS, etc.) Usually qualitative and quantitative for DUID Must meet LOD requirement Wide scope possible, but usually restricted to limited menu Labor intensive = time consuming = expensive Often different analytical scheme and analyses for different drugs

Copyright 2014, Dwain C. Fuller, D-FTCB

Side Note: New Technologies

Copyright 2014, Dwain C. Fuller, D-FTCB

The Dream!

Side Note: New Technologies

Copyright 2014, Dwain C. Fuller, D-FTCB

The Reality!

Alcohol Drugs

Copyright 2014, Dwain C. Fuller, D-FTCB

Alcohol vs. Drugs in Driving

The most prevalent “drug”

Extremely well-studied and understood

Reasonably dependable dose-response relationship

“Per se” concentration

Hundreds of potential drugs

Prevalence not well-understood May be over or underestimated Less studied in a controlled fashion

Dose-response relationships less understood and more diverse

Proof of impairment usually required

Challenges for the Toxicologist

Combatting “cum hoc ergo propter hoc” logic. Understanding and appreciating literature biases. Drug impairment is often different to alcohol impairment. Motor skills Drowsiness Cognitive impairment

Drugs with different “phases” of action. Tolerance Stimulant use and abuse

How much is too much? (What equals 0.08 EtOH?) Polypharmacy and drug-alcohol interactions How can the report be negative? Forensic toxicology is not practiced in a vacuum!

Copyright 2014, Dwain C. Fuller, D-FTCB

The Burden of Proof

Copyright 2014, Dwain C. Fuller, D-FTCB

Impairment

DR

E/S

FS

T/O

bser

vatio

ns

Driving Behavior

Copyright 2014, Dwain C. Fuller, D-FTCB

Too fast

Too slow

Weaving

At cause accident Hitting fixed object

Hitting other vehicles or pedestrians

Hit and run

Failure to abide by traffic rules Traffic signs or signals

Wrong way driving

Stopped on road

SFST and DRE

Copyright 2014, Dwain C. Fuller, D-FTCB

SFST – Standardized Field Sobriety Test HGN – Horizontal Gaze Nystagmus WAT – Walk and Turn OLS – One Leg Stand

DRE – Drug Recognition Exam (or Expert) DRE examinations, as opposed to SFST, are best conducted under a

controlled environment rather than roadside. HGN – Horizontal Gaze Nystagmus VGN – Vertical Gaze Nystagmus Lack of Convergence Pupil Size Reaction to Light Pulse Blood Pressure Temperature Muscle Tone

DRE 12 Steps

1. Breath alcohol test Does alcohol account for the observed impairment? Usually no DRE eval if BAC>0.08

2. Interview of Arresting Officer3. Preliminary Examination Eye examinations and subject is questioned for any

evidence of medical complication4. Eye Examination HGN VGN Lack of convergence

Slide Courtesy of Laura Liddicoat, Wisconsin State Laboratory of Hygiene

DRE 12 Steps

5. Divided Attention Psychophysical Tests Romberg Balance Finger to Nose WAT OLS

6. Vital Signs Pulse (x3) Body temperature Blood Pressure

7. Dark Room Pupil size in room light, near total darkness, direct light

8. Muscle Tone

Slide Courtesy of Laura Liddicoat, Wisconsin State Laboratory of Hygiene

DRE 12 Steps

9. Examination for injection sites

10. Suspect’s Statements / Other Observations

11. Opinion of Evaluator DRE documents conclusions and category(s) of

drugs causing the impairment

12. Toxicological Examination Specimen for Toxicology testing is obtained and

sent to laboratory for analysis

Slide Courtesy of Laura Liddicoat, Wisconsin State Laboratory of Hygiene

DRE Matrix

Copyright 2014, Dwain C. Fuller, D-FTCB

Pupils

Copyright 2014, Dwain C. Fuller, D-FTCB

Horizontal Gaze Nystagmus

Copyright 2011, Dwain C. Fuller

Involuntary jerking of the eyes as angle of horizontal gaze increases

Caused by alcohol and CNS depressants

Angle of onset is related to BAC

Which Drugs Can Impair Driving?

Any drug that changes the way we perceive or react to the environment. (Perception, tracking, coordination, reaction time, attention, judgment, etc.) CNS depressants Multiple effects

Cannabinoids Chiefly cognitive

Stimulants Can enhance driving in some doses

Risk-taking

Exhaustion

Opioids drowsiness

Copyright 2014, Dwain C. Fuller, D-FTCB

Copyright 2014, Dwain C. Fuller, D-FTCB

CNS Depressants

HGN

Confusion

Sedation

Drowsiness

Droopy eyelids

Slurred speech

Poor balance

Poor coordination

Disorientation

Memory loss

Slowed reaction time

Low blood pressure

Slowed pulse

Poor divided attention performance

Benzodiazepines and Tolerance

Copyright 2014, Dwain C. Fuller, D-FTCB

Benzodiazepines are CNS depressants with activity ranging from anesthetic induction to sleep enhancement to anti-anxiety.

All benzodiazepines can impair driving.

Not all drivers with benzodiazepines on board are necessarily impaired.

Tolerance to the psychomotor and sedative effects of short half-life benzodiazepines can develop within a matter of days to a few weeks.

Supra-therapeutic and acute doses of short half-life benzodiazepines are the most impairing.

Copyright 2014, Dwain C. Fuller, D-FTCB

CNS Stimulants

Improved reaction time

Relief from fatigue

Improved vigilance

Increased risk taking

Increased blood pressure

Increased pulse

Increased body temperature

Agitation

Hyperactivity

Irritability

Confusion

Suspiciousness

Paranoia

Delusions

Hallucination

Violence

Exhaustion

Fatigue

Hypersomnolence

Depression

Stimulants

Copyright 2014, Dwain C. Fuller, D-FTCBLogan, BK. Journal of Forensic Sciences. 41(3) 1996, 457-64

So does the number mean anything?

Copyright 2014, Dwain C. Fuller, D-FTCB

Provides the toxicologist with a starting point.

With some limitations, can be compared to normal therapeutic ranges.

Should be interpreted with caution.

Should never be interpreted without context.

Toxicologist should understand the limitations of his/her interpretative paradigm. Naturalistic studies

Controlled studies

Naturalistic studies

Copyright 2014, Dwain C. Fuller, D-FTCB

Studies often report the drug concentration of people who are stopped for poor driving, wrecks, or some other behavior that bring them in contact with law enforcement.

This produces a selection bias toward those who are impaired by a substance, and omits, perhaps even a majority of, subjects who may be unimpaired at the same concentrations.

These studies typically provide no information about how many people were stopped or came into contact with law enforcement for these same reasons in which no drugs were detected.

Naturalistic studies

Copyright 2014, Dwain C. Fuller, D-FTCB

Controlled Studies

Copyright 2014, Dwain C. Fuller, D-FTCB

The preferred studies are those which are placebo controlled and double blind. At times, actual driving performance (SDLP) Behavioral tests < Simulated driving < Actual driving Even at best, not real world

Limitation on controlled studies Institutional Review Board Issues Ethics Safety

Cost and Logistics Food Housing Compensation

SDLP – Standard Deviation of Lateral Position

Copyright Dwain C. Fuller 2012

Verster JC, Roth T. Int J Gen Med. 2011; 4: 359–371.

So why not use “per se” concentrations?

Copyright 2014, Dwain C. Fuller, D-FTCB

18 states have some form of “per se” concentrations for commonly abused illicit drugs ranging from no tolerance to specific concentrations Pros Eases interpretative burden

May discourage illicit drug use

Cons Choosing the per se concentration

Some drugs share metabolites with legitimate drugs

Legal THC use Marinol

Sativex

Prescription medications?

Synthetic Cannabinoids “Bath Salts”

Copyright 2014, Dwain C. Fuller, D-FTCB

New Drugs

Spice, K2, etc. Amphetamine analogs sold as “bath salts”, “plant food”, etc.

Synthetic Cannabinoids

Copyright 2014, Dwain C. Fuller, D-FTCB

Sold as incense or potpourri, “Not for Human Consumption”

Most were developed for pharmaceutical research on the cannabinoid receptor

Some are DEA scheduled

Ever moving target

“Bath Salts” - Cathinones

Copyright 2014, Dwain C. Fuller, D-FTCB

Widely varied synthetic stimulants and hallucinogens similar to amphetamine

Based on cathinone or “Khat” Native to Africa

Leaves chewed or made into tea

Some are DEA scheduled

Ever moving target

Questions and Discussion

Copyright 2014, Dwain C. Fuller, D-FTCB