Lab Exercise-Drug Recognition Evaluation

I am a police officer and Drug Recognition Expert and specialize in drug impaired driving. The drug impaired driving program classifies 7 different categories of drugs based on their psychological and physiological effects on the body. A full drug evaluation is a process which includes a series of questions, blood pressure, pulse, temperature, divided attention tests, eye examinations, and toxicology by way of blood or urine.


http://www.paloaltodailynews.com/pics/padn/400xN/padn/2006-11-18-sv-car-crash

There are seven categories of drugs that we consider for impairment. The drug symptomatology (and their exceptions) is categorized on a matrix card for quick reference. A much more intensive list of signs and symptoms are also utilized. Although each person is different, the majority of the time, drugs act a certain way upon the human body, both psychologically and physiologically.

http://www.bear-aide.com/images/DRC.jpg

The primary tasks for a Drug Recognition Expert are to determine driving impairment above and beyond alcohol impairment, if alcohol only is impairing the person, if the person has a medical condition or injury causing the impairment, or if the person is not impaired at all.

A drug evaluation consists of questions asked of the subject about what they have had to eat or drink in the past 24 hrs, physical disabilities and impairments, medication and drug usage, and sleeping habits. We also ask the subject if they know the approximate time without looking at a watch or clock. These questions assist in determining impairment factors, but also give us a chance to evaluate a persons speech patterns, body language, environmental interactions, and internal body clock.

Regardless of whether or not alcohol is suspected for the impairment, I request a breath sample showing the breath alcohol content from a deep lung breath from the subject. I can use an instrument calibrated to obtain and process breath alcohol.


http://www.alcoholtest.com/images/intox8000.gif


After the series of questions and breath sample, I request the subject perform a Standardized Field Sobriety test called Horizontal Gaze Nystagmus (HGN.) Nystagmus is an involuntary jerking of the eyeball which is not normally visible to the naked eye. However, certain drugs enhance nystagmus to the point where it is visible. Central nervous system (CNS) depressants (including alcohol), inhalants, and dissociative anesthetics (such as PCP) enhance nystagmus. There are other types of nystagmus, but for law enforcement purposes, I look for nystagmus resulting from drug use or a recent head injury. While having the subject perform this test, I look for equality in pupil size, the nystagmus itself, and how the person balances and follows instructions.


http://www.nhtsa.dot.gov/people/injury/enforce/nystagmus/hgn.jpg

The subject also performs divided attention tests such as the Walk and Turn, One Leg Stand, Rhomberg Balance, and the Finger to Nose test.

After completion of the divided attention tests, eye examinations are completed in which the subject's pupil size is measured in room light, near total darkness (NTD), and direct light. The pupil size is documented as normal, dilated, or constricted. During the direct light examination, the reaction to light (RTL) of the pupil is checked for normal reaction, slow reaction, or little to no reaction to the light stimulus.

Dilated Pupil

http://farm1.static.flickr.com/147/418554887_c823e282e7.jpg

Constricted Pupil

http://www.washoe.k12.nv.us/schools/safeanddrugfreeschools/images/Constricted_pupils.jpg

Pulse is checked 3 times during the examination and blood pressure once. Temperature is also taken during the evaluation. Once the evaluation is completed in its entirety, a blood or urine sample is obtained from the subject to identify the drugs used.

1) For the purposes of this lab experiment, I am taking the information from anonymous individuals that are under the influence of either a CNS stimulant drug, cannabis, or a narcotic analgesic, and testing whether or not the human physiological reactions fall into drug symptomatolgy categories for the certain drugs. I placed evaluations in 3 piles and mixed them up and randomly chose 1 test subject from each drug category. I will test the following aspects of the drug evaluation:

• Blood Pressure-normal 120/80
  
• Pulse rate- normal (for DRE purposes) 60-90 bpm
  
• Temperature-normal 98.6 plus or minus 1 degree
• Pupil Size-normal: room light 2.5-5.0mm, NTD 5.0-8.5mm, direct light 2.0-4.5mm
  
• Pupillary Reaction to Light-normal, slow, or little to none
  

The common symptoms for the 3 categories are as follows:

CNS Stimulants:

• BP-elevated
  
• Pulse-elevated
  
• Temperature-elevated
  
• Pupil size-dilated
  
• RTL-slow

Cannabis:

• BP-elevated
• Pulse-elevated
  
• Temperature-normal
• Pupil size-dilated
• RTL-normal

Narcotic Analgesics:

• BP-below normal
• Pulse-below normal
  
• Temperature-below normal
• Pupil size-constricted
• RTL-little to none

All subjects reflected in this are anonymous and the information has been utilized in part from previous drug evaluations. The toxicology has been confirmed by an accredited lab.

2) Hypothesis:

I expect that a person psychoactively under the influence of the either a CNS stimulant, cannabis, or a narcotic analgesic will exhibit symptoms common with that drug category symptomatology.

Subject 1, 21 year old male: CNS Stimulant

• BP-140/100
  
• Pulse-114, 120, 106 bpm
  
• Temperature-100.2
  
• Pupil size- room light-7.5mm, NTD-8.5mm, direct light-7.0mm
  
• RTL-slow
  

Subject 2, 35 year old female: Cannabis

• BP-150/90
• Pulse-96, 100, 88 bpm
  
• Temperature-99.0
• Pupil size-room light-7.0mm, NTD-9.0mm, direct light-5.5mm
• RTL-normal

Subject 3, 55 year old male: Narcotic analgesics

• BP-100/60
• Pulse-54, 58, 52 bpm
  
• Temperature-96.2
• Pupil size-room light-3.0mm, NTD-3.5mm, direct light-3.0mm
• RTL-Little to none visible

3) For DRE evaluations I used the following equipment:

• Sphygmomometer (manual, not electric)
• Stethoscope
• Thermometer and sheath
• Nitrile gloves
• Pupil light
• Red glow stick stimulus (for pupil test)
• Pupillometer
• Watch

4) Data and bar graphs:

SYSTOLIC/ DIASTOLIC BLOOD PRESSURE
190
180
170
160
150							SYSTOLIC B/P
140							DIASTOLIC B/P
130
120							NORMAL
110							NORMAL
100
90
80
70
60
50
40
30
20
10
	CNS STIM	CANN	N/A	NORM
Pulse/ BPM
122
120
118
116
114
112
110
108
106
104
102
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
68
66
64
62
60
58
56
54
52
50
48
	CNS STIM			CANN			N/A			NORM
TEMP
102
101
100
99
98
97
96
95
94
	CNS STIM	CANN	N/A	NORM
PUPIL SIZE: ROOM LIGHT, NTD, DIRECT
9.5
9								NTD
8.5								ROOM
8								DIRECT
7.5
7								ROOM/ DIRECT THE SAME
6.5
6
5.5
5								NTD NORM
4.5								ROOM NORM
4								DIRECT NORM
3.5
3
2.5
2
1.5
1
	CNS STIM	CANN	N/A	NORM

5) The different measurements reflected on the DRE evaluations support the hypothesis. For each drug category, the measurements are accurate for the drug symptoms. A couple anomalies in the data in that the subject under the influence of a CNS stimulant had pupils of 8.5mm in NTD. That is the normal range, but in the high end. However, for DRE purposes, the totality of the pupils show a consistent dilation, which is how the documentation would occur. The other anomaly is the subject under the influence of cannabis had one pulse at 88 bpm which is in the normal range, rather than elevated. Again, the other 2 are elevated which would categorize as a whole as elevated.

6) One of the problems with the technique I chose is picking only one evaluation for each category, instead of more than one, which may have reflected less consistency with the drug symptoms. Also, polydrug use is a factor with drug evaluations and trying to find single category drug use is difficult.

7) Overall, the drug symptomatology for each of the 3 categories; CNS stimulants, cannabis, and narcotic analgesics are consistent with what the subjects exhibited during their DRE evaluations.