Transcript Waiting for the Patient to “Sober Up”: Effect of Alcohol

Waiting for the Patient to “Sober Up”:
Effect of Alcohol Intoxication on
Glasgow Coma Scale Score of Brain
Injured Patients
Jason L. Sperry, MD, Larry M. Gentilello, MD, Joseph
P. Minei, MD, Ramon R. Diaz-Arrastia, MD, PhD,
Randall S. Friese, MD, and Shahid Shafi, MD, MPH
J Trauma. 2006;61:1305–1311.
Background
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The Glasgow Coma Scale (GCS) is a
physiologic measure of level of
consciousness. It is commonly used to
assess severity of traumatic brain injury (TBI).
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13~15 (mild), 9~12 (moderate), ≤8 (severe)
widely used for clinical decision making
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ATLS guideline: GCS ≤8 :endotracheal intubation
Brain Trauma Foundation’s (BTF) management
guidelines: GCS ≤8 and abnormal head CT scan:
intracranial pressure monitoring
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TBI is the most important determinant of
GCS score, but factors other than TBI may
alter level of consciousness and GCS score.
Alcohol (CNS depressant) intoxication is
reported to be present in 35% to 50% of TBI
patients
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≥80 mg/dL: minor motor impairments
≥150 mg/dL: gross motor impairment (balance
and coordination)
≥200 mg/dL: amnesia or coma
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The implications of whether alcohol confounds the
GCS score of patients with brain injury are important.
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If alcohol intoxication decreases the GCS score of TBI
patients,
 the effect of alcohol needs to be accounted for, so that
unnecessary interventions are not performed.
if alcohol intoxication does not significantly decrease the
GCS score of TBI patients,
 a low GCS score should not be attributed to alcohol
intoxication, and other causes should be aggressively
sought so that a delay in needed interventions does not
occur.
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Published data on the effects of alcohol on
GCS scores of TBI patients are conflicting.
The purpose of the current study was to
determine whether alcohol intoxication alters
GCS scores of patients with and without TBI.
Our specific hypothesis was that patients
intoxicated with alcohol had a reduced GCS
score compared with nonintoxicated patients
with similar severity of brain injury.
Methods
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A 10-year retrospective analysis of a large,
urban Level I trauma center registry (1995–
2004) was undertaken.
The study population consisted of blunt headinjured patients who were tested for BAC in
the emergency department.
Patients with incomplete information on initial
GCS score or final Abbreviated Injury Score
(AIS) for head injuries, and those with fatal
head injuries (AIS 6), were excluded.
n=1075
Nonintoxicated
Intoxicated
(BAC=0 mg/dL)
(≥legal limit for
driving, 80mg/dL)
n=504
n=571
Nonintoxicated patients were
more often injured because of
MVC whereas intoxicated
patients were more likely injured
by assault.
nonintoxicated patients sustaining
more severe head injuries
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Correlation between BAC level and GCS score
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stratified by severity of head injury
The effects of systemic hypotension, airway control, and
severity of injury on measurement of GCS score
Severely intoxicated patients (BAC >250 mg/dL)
Specific GCS components (eye, verbal, and motor
scores).
Patients without documented TBI (n= 4,988)
Multivariate linear regression techniques were used to
determine whether BAC was an independent predictors
of GCS score.
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For all statistical tests, a p value <0.05 was
considered significant.
Because a small change in mean GCS score
may be statistically significant with this larger
sample size, we defined a difference of at
least one point in total GCS score as clinically
significant.
Results
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There was no linear relationship between
blood alcohol concentration and GCS score.
(Spearman correlation coefficient =0.033, p= 0.275)
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There was no difference in mean GCS score
between the two groups.
(nonintoxicated 10.1± 4.8, intoxicated 10.3± 4.7, p =0.500)
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When stratified by
severity of head injury,
difference in mean
GCS score between the
two groups was less
than a single point in all
grades of TBI, except in
those with head AIS 5,
where the difference
was 1.4 GCS points.
Endotracheal intubation
Hypotension (SBP<90 mmHg)
Severe injury (ISS>18)
Normotensive
Severely injured
difference in mean GCS score was 1.5
difference in mean GCS score was 1.4
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Similarly, mean GCS
score did not differ by
more than 1 point in
each TBI category in
the severely intoxicated
patients (BAC >250
mg/dL).
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We compared mean eye,
verbal, and motor scores
in nonintoxicated versus
intoxicated patients for
each TBI category and
did not find any
difference greater than 1
point.
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Mean GCS score for patients without
documented TBI (n=4,988) also showed no
difference greater than a single GCS point.
(nontoxicated 12.8 ±0.08 versus intoxicated 13.2 ±0.06, p >0.001)
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Blood alcohol concentration was not an independent
determinant of GCS score in a multivariate model.
Discussion
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The primary finding of this study is that
alcohol intoxication does not significantly alter
the GCS score of trauma patients with TBI,
except for patients with the most severe
Injuries.
These results reject the study hypothesis
(and conventional wisdom), and validate the
value of the GCS as a measure of level of
consciousness determined by severity of TBI,
unaffected by alcohol intoxication.
Possible explanation of our findings
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The effect of alcohol on an individual patient’s
level of consciousness is highly variable,
depending upon the frequency and rate of
alcohol consumption, as well as the rate of its
metabolism.
Hence, although an individual patient’s GCS
score may be lowered by alcohol intoxication,
it may not be true for the group as a whole.
Possible explanation of our findings
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level of intoxication used in this study (mean and
median BAC around 200 mg/dL) was not high enough
to impair patients’ mental status.
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Galbraith reported that a BAC>200 mg/dL was required to
depress the level of consciousness.
Jagger found that alcohol significantly lowered GCS scores of
TBI patients and the effect was most pronounced in those with
a BAC>200. But, interestingly, even in this group, there was
no effect of alcohol on GCS score of 70% of the patients.
In another study, Minion reported that 88% of patients with
BAC in excess of 400 mg/dL were alert and oriented to time,
place, and person.
It is also entirely possible that BAC has little meaning
because of the individual’s tolerance of alcohol.
Possible explanation of our findings
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Finally, it is possible that the GCS score is
not a sensitive measure of mental status in
intoxicated patients with TBI.
Of course, the most logical explanation of our
findings is that any decrease in the level of
consciousness in trauma patients is a result
of factors other than alcohol intoxication,
most important of which is the severity of
brain injury.
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Other factors that may affect the level of
consciousness include severity of other nonneurologic injuries, presence of shock or
hypothermia, concomitant use of other CNS
depressants, and hypoxia or hypercarbia.
Our findings underscore the fact that in
patients with depressed GCS score, these
factors should be aggressively sought and
treated, without waiting for alcohol to wear off.
Limitations of this study
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It is a single institution experience, and may
only reflect local patient characteristics.
Retrospective reviews: unmeasured or
unknown confounding variables
Throughout the study period, BAC levels
were drawn selectively, likely resulting in
selection bias.
Conclusion
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Alcohol intoxication does not reduce the GCS
score more than one point for patients with
TBI, except for patients with the most severe
injuries.
Hence, diagnostic and therapeutic
interventions indicated by patients’ GCS
scores should be undertaken promptly, and
not delayed waiting for patients to “sober up”.
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