Waiting for the Patient to

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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. 20066113051311.

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Background

• 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).
• 1315 (mild), 912 (moderate), 8 (severe)
• widely used for clinical decision making
• ATLS guideline GCS 8 endotracheal intubation
• Brain Trauma Foundations (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
• 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.
• 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.

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Methods

• A 10-year retrospective analysis of a large,
  urban Level I trauma center registry (19952004)
  was undertaken.
• The study population consisted of blunt
  head-injured 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.

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Nonintoxicated (BAC0 mg/dL) n571
Intoxicated (legal limit for driving,
80mg/dL) n504
n1075
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nonintoxicated patients sustaining more severe
head injuries
Nonintoxicated patients were more often injured
because of MVC whereas intoxicated patients were
more likely injured by assault.
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• Correlation between BAC level and GCS score
• 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 gt250 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 lt0.05 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.

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Results

• There was no linear relationship between blood
  alcohol concentration and GCS score.
• (Spearman correlation coefficient 0.033, p
  0.275)
• 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.

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Hypotension (SBPlt90 mmHg)
Endotracheal intubation
Severe injury (ISSgt18)
Normotensive difference in mean GCS score was 1.5
Severely injured 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 gt250 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 (n4,988) also showed no difference greater
  than a single GCS point.
• (nontoxicated 12.8 0.08 versus intoxicated 13.2
  0.06, p gt0.001)

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• Blood alcohol concentration was not an
  independent determinant of GCS score in a
  multivariate model.

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Discussion

• 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.

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Possible explanation of our findings

• The effect of alcohol on an individual patients
  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 patients GCS score
  may be lowered by alcohol intoxication, it may
  not be true for the group as a whole.

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Possible explanation of our findings

• level of intoxication used in this study (mean
  and median BAC around 200 mg/dL) was not high
  enough to impair patients mental status.
• Galbraith reported that a BACgt200 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 BACgt200. 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 individuals tolerance of
  alcohol.

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Possible explanation of our findings

• 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
  non-neurologic 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.

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Limitations of this study

• 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.

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Conclusion

• 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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Thanks for your attention!