Transcript Forensic Toxicology - St. Edward's University

Ethanol Toxicology
 Ethanol production
 Fermentation of sugar or starch
 Can only achieve 20% ethanol
 Distillation
 Distilled alcoholic beverages are usually 40
to 50% ethanol by volume (80-100 proof)
 Elimination
 5-10% in the urine
 Saliva, expired air and sweat
 Liver (enzymatic oxidation to
acetaldehyde, acetic acid and carbon
dioxide)

Breath
Ethanol
Testing
Theory
 Henry’s law
 Ethanol in breath Vs ethanol in blood
 2100 to 1 ratio
 2300 to 1 ratio
 Types of analyzers
 Chemical
 Reaction of ethanol with potassium
dichromate/sulfuric acid solution
 Colored solution that results is measured
spectrophotometrically
 IR spectrophotometry
 Electrochemical oxidation - fuel cell
Assessment of Ethanol
Impairment
 In a British study:
 Detectable deterioration
of drivers at between 30
– 50 mg/dL
 Obvious deterioration
observed at between 60
– 100 mg/dL
 In another British study:
 Pilots exhibited
impairment at 40 mg/dL
 Blood alcohol concentration:
 10-50 mg/dL: Impairment detectable by
special tests
 30-120 mg/dL: Beginning of sensorymotor impairment
 90-250 mg/dL: Sensory-motor
incoordination; impaired balance
 180-400 mg/dL: Increased muscular
incoordination; apathy; lethargy
 250-400 mg/dL: Impaired consciousness;
sleep; stupor
 350-500 mg/dL: Complete
unconsciousness; coma
 450 and greater mg/dL: Death from
respiratory arrest
Example:
Find the BAC for 128 lb. male drinking 12 oz. beer (4.5 percent alcohol
by volume) in one hour's time.
A.
Convert pounds to kilograms: 128lbs / (2.2046 lbs/kg)
= 58.06 kg.
B.
Find total body water: 58.06 kg. x .58 = 33.675 liters or
33,675 milliliters water
C.
Determine the weight in grams of 12 oz. Of 4.5% alcohol:
12 oz. x .045 x 29.57 ml/oz x 0.79 g/ml = 23.36 grams
D.
If we put 1 oz. of alcohol into the subject's total body water, we
would have grams of alcohol/ml. of water, e.g.,
23.36 grams ÷ 33,675 milliliter = .0006937 grams alcohol/ml of water
E.
We now want to find the alcohol concentration in the blood. Blood
is composed of 80.6 percent water; therefore, .0006937 X .806 =
.000559 grams alcohol/milliliter blood.
F.
Instead of grams alcohol per milliliter blood, we need the
figure in terms of grams per 100 milliliter, also known as grams
percent. Multiply the .000559 grams alcohol/ milliliter blood by
100, i.e., .000559 grams per milliliter X 100 = .0559 grams alcohol
per 100 milliliters, or .0559.
(This is the BAC which 1 oz. of alcohol would produce in a 128 lb
male if there were instantaneous consumption, absorption, and
distribution of the alcohol throughout the body.)
G.
To adjust for the actual amount consumed, one multiplies the
above figure by the amount of alcohol in the beverage consumed.
Thus, if the 128 lb. male described above consumed a single 12 oz.
can of beer containing 4.5 percent alcohol by volume, he would have
consumed 12 oz. X .045 = .54 oz. of alcohol. Since 1 oz. of alcohol
would produce a BAC of .0559 and .54 oz. of alcohol has been
consumed, the actual alcohol level would be .0559 x .54 = .030 BAC
for one can of beer.
H.
In real life, time must pass for the consumption, absorption, and distribution of alcohol
throughout the body. Therefore, we calculate what the actual BAC level would be at the end of one
hour after consuming the single can of beer. During this period, the body would have disposed of
alcohol through metabolism at a rate characteristic of that individual, primarily his recent frequency
and quantity of drinking. Utilizing a conservative (below average) metabolism rate of .012 per hour,
we can calculate the BAC level as .0302 - .012 per hour X 1 hour = .0182 BAC at the end of one hour
for our 128 lb. male who drank 1 can of beer. (As noted above, the BAC Estimator program roundsoff BAC estimates to two decimal places, thus it would report a calculated BAC of .0182 as .02.) Note
that the time of metabolism is calculated from the beginning of drinking, not when the consumption is
completed.
Stages of Acute Alcohol Intoxication*
Blood-Alcohol
Concentration
g/ 100mL
0.01-0.05
Stage of
Alcoholic
Influence
Sub clinical
Clinical Signs/ Symptoms
Influence/ effects not apparent or obvious
Behavior nearly normal by ordinary observation
Impairment detectable by special tests
0.03-0.12
Euphoria
Mild euphoria, sociability, talkativeness
Increased self-confidence; decreased inhibitions
Diminution of attention, judgment, and control
Beginning of sensory-motor impairment
Slowed information processing
Loss of efficiency in critical performance tests
0.09-0.25
Excitement
Emotional instability; loss of critical judgment
Impairment of perception, memory, and comprehension
Decreased sensory response; increased reaction time
Reduced visual acuity, peripheral vision, and glare
recovery
Sensory-motor incoordination; impaired balance
Drowsiness
0.18-0.30
Confusion
Disorientation, mental confusion; dizziness
Exaggerated emotional states (fear, rage, grief, etc.)
Disturbances of vision (diplopia, etc.) and of perception of
color, form, motion, dimensions
Increased pain threshold
Increased muscular incoordination; staggering gait; slurred
speech
Apathy, lethargy
0.25-0.40
Stupor
General inertia; approaching loss of motor functions
Markedly decreased response to stimuli
Marked muscular incoordination; inability to stand or walk
Vomiting; incontinence of urine and feces
Impaired consciousness; sleep or stupor
0.35-0.50
Coma
Complete unconsciousness; coma; anesthesia
Depressed or abolished reflexes
Subnormal temperature
Impairment of circulation and respiration
Possible death
0.45+
Death
Death from respiratory arrest
*Reprinted by permission of K.M. Dubowski, 1997.