THE
SCIENTIFIC BASIS FOR THE DEFENSE OF DUI IN THE FED STATE
David Anaise MD JD
520-628-7777
Defense of a person arrested for DUI has long been based primarily on attempts
to discredit the accuracy of the breath analyzer and show that for a variety of technical and
scientific reasons the alcohol level measured by the Breath analyzer during the
arrest was in error. In response to this defense, legislators have passed laws
that have now essentially codified that the result of breath analyzer
measurements must be presumed to be as accurate as venous blood alcohol. As a result, such defenses
have largely been denied. In this article I argue that even if the results of
breath analyzer could be rendered reasonably accurate in the post absorptive
phase, it should not be used in the absorptive state because breath analyzer
overestimates the true BAC by as much as 100%. The challenge, thus
is not on the accuracy of the breath- analyzer but rather on the theory that it
is impermissible to admit such results as scientist agree that during the
absorptive phase equilibration of alcohol has not yet occurred and the pulmonary
vein blood alcohol ( estimated by BrAC) does not reflect the alcohol levels in
the brain.
The absorptive phase also has unique advantages in the defense of the accused
because of the effect of first pass metabolism which effectively reduces by half
the amount of alcohol circulating in the systemic circulation and the increased
elimination of alcohol observed in the fed state. As a result, a much larger
amount of alcohol is needed (almost twice) to intoxicate an individual in the
fed state as compared to the fasting state. A scientific defense can thus be
mounted to show that the breath analyzer in the fed state is grossly inaccurate
because based on the amount of alcohol ingested by the accused it will be
practically impossible for the BAC to reach the level of legal intoxication
measured by Widmark’s formula
First pass metabolism (FPM)
First Pass Metabolism is the difference between the quantity of alcohol that has
reached the systemic circulation by the intravenous route and the quantity that
entered the circulation by the oral route (see Figure1). As shown in Fig
1, the amount of alcohol absorbed through the bowel is only a fraction of the
alcohol dose provided assuming 100% absorbtion by the IV route.
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Gentry,
et al. at Dr. Charles S. Liebers laboratory published a study on FPM. They provided social drinkers with a generous drink
(300 milligrams per Kg dose of 10% wt/vol alcohol). When the subjects ingested
alcohol with a standard meal, 28% of the alcohol dose did not reach the systemic
circulation. In some cases, only half the dose was absorbed.
They argued that the site of the first pass is the stomach, because when alcohol
was given directly to the duodenum the BAC measured as area under the curve was
similar to the intravenous rather than intra-oral route. In experiments where
the pylorus of animals was ligated, only about a third of the alcohol reached
the systemic circulation after four hours.
The
enzymreADH responsible for degradation of alcohol is most conspicuous but not the
only enzymatic system capable of metabolizing ethanol in the gastric mucosa. ADH
is abundant in the mucus producing cells lining the mucosa of the human stomach.
The stomach ADH is efficient in eliminating alcohol because there are several
iso-enzymes that allow for handling of alcohol at different concentrations.
Dr. Michael Levitt from the Research Service Veteran Affairs Medical Center in
Minnesota Medical School agreed with Dr. Gentry’s analysis of first pass
metabolism . He stated that at least 35% of alcohol does not reach the systemic
circulation. Dr. Levitt argues however that the site of the destruction of
alcohol is the liver. According to Levitt, the first pass metabolism is
dependent on the rate of alcohol delivery to the liver. When transit from the
stomach is delayed, the liver very efficiently removes the low alcohol
concentration at first pass and prevents alcohol from arriving at the systemic
circulation. When the alcohol passes quickly into the small intestine, the liver
is overwhelmed by the amount of alcohol provided and its capacity to remove a
significant portion of alcohol from the systemic circulation is greatly
diminished. The importance of this observation is that the Widmark formula used
so frequently in laboratories assessing alcohol intoxication is often erroneous.
Why the Widmark formula is grossly
inaccurate at the fed state
The formula used by Widmark is rather simple and is based on the uniform
distribution of alcohol in water. Basically, the blood alcohol concentration BAC
is the amount of alcohol ingested, divided by the amount of water in the body.
Based on Widmark formula NHTSA created a chart used by law enforcement officers
where they can plot the body weight and the number of drinks in order to arrive
at the projected BAC or conversely, use the level of BAC measured in order to
state how many drinks the person has ingested prior to his arrest.
If Widmark formula is accurate then a group of people given identical amount of
alcohol per Kg body weight should have reasonably similar BAC. In fact, as
shown in Fig. 2 Jones et al have shown that when a group of volunteers received
0.6g of alcohol per Kg The BAC measured varied from as low as 0.04 to as
high as 0.18
Fig 2
Widmark formula was found to consistently overestimate the measured BAC ( dash) in both males ( upper) and females ( lower graph) ( see Fig 3)
Fig 3.
The Widmark formula is unreliable for three reasons. First, it doesn’t take into effect the different and large variation in the amount of water which exists among individuals and specifically, between men and women. The amount of alcohol in the body, also called volume of distribution, has been known to range from .59 to .90 for males and between .46 to .06 in females. Second, this formula assumes that the elimination rate is 015% per hour for all individuals, while studies have shown great differences in the rate of elimination among individuals, ranging from .011% to .022% and in alcoholics, up to .43% gram percent per hour.
Third, Widmark’s analysis is based on volunteer studies which
are very different from studies of social drinkers. Widmark has used volunteers
who have fasted overnight and were provided with one drink designed to raise the
blood alcohol level to barely the legal limit of .08%. In contrast, the typical
social drinker drinks several drinks over time and often mixed with food.
Calculation of BAC in the fed state
A.W. Jones, perhaps the most noted investigator of alcohol metabolism observed
that when the subject was given .8 gram per Kg of alcohol on an empty stomach,
the subject reached the intoxicating level of .10% at 40 minutes. When the same
subject was fed breakfast, his blood alcohol level, at 40 minutes, was less than
.05% or half of the maximum BAC during fasting. In contrast to a peak of 40
minutes in the fasting stage, the subject’s BAC after breakfast, peaked at two
hours. Finally, the area under the curve was significantly smaller. Fig 4
. Dr Jones
explained his results by stating that the delayed absorption of alcohol in the fed
state enhanced the first pass metabolism action discussed earlier. In the
fed state the liver
more efficiently removed alcohol from the circulation and the delay in stomach
emptying provided more time for ethanol to be destroyed
in the stomach by ADH. As more alcohol is destroyed by ADH in the stomach
and more alcohol is destroyed by the liver less alcohol is absorbed into the systemic circulation. Dr.
Jones opined:
“A more prolonged absorption phase and a later occurring peak was frequently
observed when alcohol was taken together with or after a meal compared with
drinking on an empty stomach.”
He then went on to say : “The BAC calculated according to Widmark’s equation
vastly exceeded the actual BAC sometimes by as much as 50% or more."
Thus,
a combination of first pass metabolism, a more gradual delivery of alcohol into
the liver and a faster metabolism associated with the fed state dramatically
change the Widmark calculation. If four bottles of beer would bring the BAC
level to .08% in a 70 kg. man, eight bottles of beer are needed to reach the
.08% in the fed state ( see figure above)
More recently ( ( Br J Clin Pharmacol. 1997 Dec;44(6):521-6. )) Dr. Jones
confirmed these observations by comparing the BAC obtained after IV
administration, in a fasting state and in the fed state. The corresponding areas
under the concentration-time profiles (AUC) and the peak BAC were twice as high
in fasting then subjects in the fed state. ( 1767 +/ -549, after meal and 3210
+/- 527 and 4786 +/- 446 mg dl-1 min after fasting and i.v. infusion,
respectively). Dr. Jones opined:" Drinking ethanol after eating a
meal, regardless of the nutritional composition, decreases the systemic
availability of ethanol. Because gastric emptying is slow and more prolonged
with food in the stomach, the delivery of ethanol to the duodenum and the liver
will be highly variable as will the hepatic clearance of ethanol".
Was the client intoxicated when he was
arrested during the absorptive phase ?
Assume the accused is charged with driving with blood alcohol level of .16%, The
state will argue that it would take the ingestion of eight beers to reach BAC of
0.16%. Defense expert can show that as twice the amount of alcohol is needed to
raise the level of BAC to intoxicated level at the fed state, 16 bottles of beer
rather than the 8 claimed by the state would be necessary to bring the level of
BAC to .16%. The illustration below depicts a man weighing 180 lbs who was
arrested one hour after drinking with and without meal fIG.5
The fed
state thus allows for a unique scientific defense in DUI cases. Defense
can argue that based on the actual ingestion of beer as entered into evidence at trial it would
have been impossible for the accused to ingest the amount of alcohol claimed by
the state. A waiter can testify that it will be practically impossible to serve
individual 16 beers over one hour. The defense can also argue that 16 beers
consumed exceeded the capacity of the bladder, and thus, the observation that
the accused has not emptied his bladder for a lengthy period of time can be used
as another evidence why the breath analyzer analysis was erroneous.
Breath analyzer overestimates the BAC
during the fed state
Simpson has challenged the accuracy and precision of breath alcohol measurements
for subjects in the absorptive state. In an article published in Clinical
Chemistry. Simpson has analyzed the articles written on the topic and published
in the scientific literature. Specifically, he reviewed two of Dr. Jones publications, four
of Dr. Dubowski’s publications, and three of Dr. Martin’s publications; all well
respected scientists leaders and teachers of the world renowned Borkenstein
course held yearly at Indiana University. fIg. 6
Dr.
Simpson concluded:
“Results from data in the literature indicate that breath testing is not the
reliable means of estimating a subject’s BAC during absorption… during
absorption, breath test results consistently overestimate the results that would
be obtained from a blood test by as much as 100% or more.” In some cases BrAC
overestimated BAC by 230% and 190%
Figure 7 explains this phenomenon. When one plots the breath alcohol and the venous blood alcohol simultaneously measured shortly after drinking, the breath analyzer curve rises first with the venous blood alcohol lagging behind until it intersects with the declining curve of the breath analyzer . BrAc peaks in 10 minutes and register a BrAC of 0.08% when at the same time venous blood reaches only 0.02%. BAC in contrast reaches a peak in 90 minutes to a level of 0.07%.
Widmark in 1931 was the first to recognize that during the absorptive period,
“The value from air analysis and blood analysis often do not agree,” . Dubowski
and Mason in 1974, stated:
“When the blood test is allowable, an administered breath test is discriminatory
because in law enforcement practice the state of absorption is always
uncertain.”
Mason and Dubowski in their leading article stated the following: “The use of
breath has an advantage of not requiring the intervention of a physician, nurse
or hospital personnel in the enforcement procedure, but the subsequent
calculation employs several presumptions whose validity cannot be assessed in an
individual case. This is a significant disadvantage to the value of the results
in the criminal justice system of the United States.”
, “Frequently there are unacceptable discrepancies between the result of
analysis of nearly simultaneous blood/breath specimens of the same subject. It
is questionable whether Henry’s Law is properly applicable assessing the
composition of breath that has left the shelter of the minute dimensions of the
alveoli. … It is possible that in a normal subject there is sufficient
biological variation in these respiratory parameters that there is no closely
regulated blood/breath ratio as might be anticipated from Henry’s Law in a
system”
“Failure of a subject to be post absorptive could lead to breath yielding a
significant higher calculated alcohol concentration than that that is in the
venous blood. If he is not post absorptive, the result of the breath test could
be discriminatory compared to blood tests which might have saved him from a
charge of driving while intoxicated being filed.”
“the existence of considerable published data originating from presumably
competent sources showing frequent unacceptable discrepancies between the
results of analysis for ethanol in blood and breath samples from the same
subject,”
The reason for the difference between the breath analyzer alcohol concentration
and the venous blood concentration is the buffering effect of the muscles on the
amount of alcohol circulated in the blood. Majority of water in the body is
distributed in the muscle. Fig 8
Fig 8. schematically depicts the passage of alcohol in the systemic circulation. Alcohol rich blood is first taken by the portal vein from the stomach to the liver ( dark blue). The liver eliminate approximately 20% of the alcohol per hour. The inferior vena Cava transport still heavily saturated blood to the pulmonary vein. The alcohol is then transported by the arterial circulation to the entire body. When the arterial blood alcohol reaches the muscle, the alcohol rapidly distributes among the muscle cells, and thus, less alcohol is available to circulate in the blood and influence the brain centers. The rapid decrease in blood alcohol concentration allows the liver to more efficiently remove alcohol at slightly faster rate than one bottle of beer per hour. [.02% per hour] This phenomenon is called the alcohol plunge and is best seen when alcohol is administered intravenously but is also seen in fasting individuals. Fig 9 depicts such an experiment following the administration of alcohol the BAC peaks in 30 minutes and for 35 minutes it exceeds the theoretic level calculated by the Widmark formula ( see dash line). If one drew a line from the measured 30 minute peak of BAc to paralel the post absorbtive line depicted in fig. 9, the resulting area under the curve will overestimate the actual BAC by more than 100%. This is the explanation to the observation made by Simpson. Note that the BAC measured 90 minutes to 420 minutes after drinking is destroyed by the liver at a beta 0.096/hr. If the curve 30-90 minutes could have been extrapolated, all the alcohol would have been eliminated in 2 hours leading to a beta of 0.4.
The basis of any medical test is to allow time for equilibration of the measured
substance within the blood. The breath analyzer measures a disproportionate
share of portal vein blood alcohol, which reaches the lung early but does not
have sufficient time to equilibrate with the brain cells as it is removed by the
muscle and the liver. It is the venous blood which reflect the actual
equilibration of BAC with the brain cells and thus it is the venous blood which
accurately reflects the level of intoxication of the accused.
Is Breath analyzer alcohol level a better
measure of the brain alcohol level?.
Advocates of breath analyzer have argued that BrAC mimics arterial blood
alcohol. The breath-analyzer is based on the theory that the
alcohol trapped in 2100cc of air equals 1cc of venous BAC, the so called
partition coefficient ( PC ). Jones et al have shown that the PC in the
absorbtive phas is only half of the PC during the post absorbtive phase.
Thus arterial blood over estimate venous blood by 100% in the absorptive phase.
see Fig 10.
Jones , Dubowski and others have argued that the arterial blood alcohol is more important than venous blood, because it reaches the brain faster and thus, measurement of breath analyzer is more accurate for the testing of intoxication. The support for this theory is not clear. In fact data suggest that brain BAC peaks later than blood alcohol not earlier. Dr. Bazelt noted , “Since brain tissue is lower (76% )in water content than blood (81%) it is to be expected that at equilibrium brain will contain slightly less alcohol than whole blood”. Scientists Measured the alcohol level of cerebral spinal fluid have shown that maximum CSF alcohol concentration was not reached until three hours after drinking in nine of the ten subjects.Fig 11
The
advent of MRI spectroscopy allows direct in –vivo measurement of alcohol in the
brain. Mendelson et al Measured blood and brain alcohol levels in 6 healthy
adult men after consumption of 0.7 g/kg of alcohol. They found that peak blood
alcohol levels were higher (125.67 +/- 10.91 mg/dl) and earlier (35 min post
drinking) than peak brain alcohol levels (26.25 +/- 6.38 mg/dl) detected 50 min
after alcohol intake.. These studies show that fifty minutes are needed for
alcohol to equilibrate in the brain and that venous blood rather than breath
analysis is a more reliable test of brain alcohol level after equilibration.
Conclusions
Taken together, theses data suggest that a scientific defense can be mounted to
discredit the results of breath analyzer in the fed state. Defense can argue
that in the fed state breath analyzer routinely overestimate the true BAC. As
brain absorption is prolonged and delayed the brain equilibrate with venous
blood and thus venous blood rather then the breath analyzer is the correct
measure for intoxication. The absorptive phase also has unique advantages in the
defense of the accused because of the effect of first pass metabolism which
effectively reduces the amount of alcohol circulating in the systemic
circulation and the increased elimination of alcohol observed in the fed state.
As a result, a much larger amount of alcohol is needed (almost twice) to
intoxicate an individual in the fed state as compared to the fasting state.
Based on the amount of alcohol ingested by the accused and entered into evidence
it will be practically impossible for the BAC to reach the level of legal
intoxication argued by the state based on Widmark’s formula.
about the author
I am a retired liver transplant surgeon now a
lawyer. I studied and published articles in pharmacology. I have
taken the Borkenstein course in the University of Indiana 2002 and the staff
college of the FDA Washington DC 1994. I provide forensic testimony and
consultation on medical legal issue. Please see my C.V.