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442 P R I N C I P L E S A N D P R A C T I C E O F C R I T I C A L C A R E

Research vignette
Lange RT, Iverson GL, Brubacher JR, Franzen MD. Effect of blood GCS scores will likely over-estimate the severity of brain injury in
alcohol level on Glasgow Coma Scale scores following traumatic patients with abnormal head CT scans and BALs greater than
brain injury. Brain Injury 2010; 24(7–8): 919–27. 200 mg dl( ).
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Abstract Critique
Objective This study provides insight into what decision making trauma clini-
It is a common clinical perception that alcohol intoxication system- cians face on a daily basis: the confounding of alcohol intoxication
atically lowers Glasgow Coma Scale (GCS) scores when evaluating on neurological assessment including different levels of injury
traumatic brain injury (TBI). However, the research findings in this severity. Overall, the finding that GCS can be used in the majority
area do not uniformly support this notion. The purpose of this of trauma patients at face value gives confidence in assessment
study is to examine the effects of blood alcohol level (BAL) on GCS findings. Probably this confidence can be also applied to those
scores following TBI. patients with abnormal CT scans as in this study the GCS is over-
Method estimated rather than underestimated. It also reports that in higher
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Participants were 475 patients (64% male) who presented to a BALs (>200 mg dl ) the GCS is overestimated; this can also be
Level 1 trauma centre following a TBI. Patients were selected if they affirmed by experienced clinicians demonstrating the clinical
were injured in a motor vehicle accident and had an available day- validity of the study.
of-injury GCS, BAL and Computed Tomography (CT) brain scan. In terms of study design, it was a well-structured observational
Results study with well-defined inclusion and exclusion criteria, unpow-
Overall, acute alcohol intoxication did not significantly affect GCS ered, but with a strong sample (475) selected prospectively with
scores, even in patients with BALs of 200 mg dl( ) or higher. When retrospective follow up of vital sign and GCS documentation and
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controlling for the effects of injury severity, acute alcohol intoxica- CT results. However, there was no discussion relating to different
tion affected GCS scores only in those patients with BALs greater gender responses to alcohol despite 172 of the cohort being
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than 200 mg dl( ) who also had intracranial abnormalities female. Certainly this may be a question for further work in the
detected on CT scan. same area.
Conclusions
These findings suggest that GCS scores can be interpreted at face
value in the vast majority of patients who are intoxicated. However,

Learning activities

1. What effect would decreasing the concentration of extracel- patient elicits a flexion withdrawal response of the wrist, arm
lular potassium ions have on the transmembrane potential of and shoulder. Explain what this response means in terms of
a neuron? central or peripheral response.
2. Which brain structure coordinates endocrine and nervous 6. What is the pathophysiological basis for the rise in ICP? How
system activities? would this manifest on the ICP waveform?
3. Which component of the brain controls the cardiac centres, the 7. Explain the physiological mechanism for dilated (size 5), non
vasomotor centres and the respiratory rhythm centre? reactive pupils.
4. What information does the GCS provide? What does GCS 8. A patient recovering from a subarachnoid haemorrhage can
predict? not remember events prior to the haemorrhage event. What
5. During the testing of motor response a noxious stimulus is type of amnesia is this?
applied to the nail bed of the middle finger. The unconscious

ONLINE RESOURCES mulus%2520in%2520relation%2520to%2520glasgow%2520coma%25
20scale%2520observations.pdf
American Association of Neuroscience Nurses (AANN), http://www.aann.org Head Injury Society of New Zealand, http://www.head-injury.org.nz
Australasian Neuroscience Nurses’ Association, http://www.anna.asn.au Neuroscience tutorials, http://thalamus.wustl.edu/course/
The Brain Trauma Foundation, http://www.braintrauma.org Neurological Exam, http://www.neuroexam.com/neuroexam/
Brain Explorer, http://brainexplorer.org/ Neurological Foundation of New Zealand, http://www.neurological.org.nz/
Brain Injury Association Inc, http://www.biausa.org. Official Journal of the American Academy of Neurology (AAN), http://
GCS protocol, http://intensivecare.hsnet.nsw.gov.au/five/doc/gcs_R_am_rpa.pdf; neurology.org/
GCS procedure 1, http://www.nursingtimes.net/neurological-assessment-part-3- Physical Examination and Neurological Assessment, http://www.neurologyexam.
glasgow-coma-scale/1735582.article com/
GCS procedure 2,http://www.nursingtimes.net/neurological-assessment-part-4- Post traumatic amnesia protocol, http://www.psy.mq.edu.au/pta/
glasgow-coma-scale-2/1768984.article Rural Neurotrauma Assessment, http://www.racs.edu.au/media/16138/PUB_
GCS and use of painful stimulus, http://www.mpdgp.com.au/files/docs/laos%25 090824_-_Neurotrauma_(Standard_Version).pdf
20recommendations/the%2520use%2520of%2520painful%2520sti Society for Neuroscience, http://web.sfn.org/