coma scale

Glasgow Coma Scale

The Glasgow Coma Scale or GCS, sometimes also known as the Glasgow Coma Score is a neurological scale which aims to give a reliable, objective way of recording the conscious state of a person, for initial as well as continuing assessment. A patient is assessed against the criteria of the scale, and the resulting points give a patient score between 3 (indicating deep unconsciousness) and either 14 (original scale) or 15 (the more widely used modified or revised scale).

GCS was initially used to assess level of consciousness after head injury, and the scale is now used by first aid, EMS and doctors as being applicable to all acute medical and trauma patients. In hospital it is also used in chronic patient monitoring, in for instance, intensive care.

The scale was published in 1974 by Graham Teasdale and Bryan J. Jennett, professors of neurosurgery at the University of Glasgow. The pair went on to author the textbook Management of Head Injuries (FA Davis 1981, ISBN 0-8036-5019-1), a celebrated work in the field.

GCS is used as part of several ICU scoring systems, including APACHE II, SAPS II, and SOFA, to assess the status of the central nervous system. A similar scale, the Rancho Los Amigos Scale is used to assess the recovery of traumatic brain injury patients.

Elements of the scale

Glasgow Coma Scale
1 2 3 4 5 6
Eyes Does not open eyes Opens eyes in response to painful stimuli Opens eyes in response to voice Opens eyes spontaneously N/A N/A
Verbal Makes no sounds Incomprehensible sounds Utters inappropriate words Confused, disoriented Oriented, converses normally N/A
Motor Makes no movements Extension to painful stimuli Abnormal flexion to painful stimuli Flexion / Withdrawal to painful stimuli Localizes painful stimuli Obeys Commands

The scale comprises three tests: eye, verbal and motor responses. The three values separately as well as their sum are considered. The lowest possible GCS (the sum) is 3 (deep coma or death), while the highest is 15 (fully awake person).

Best eye response (E)

There are 4 grades starting with the most severe:

  1. No eye opening
  2. Eye opening in response to pain. (Patient responds to pressure on the patient’s fingernail bed; if this does not elicit a response, supraorbital and sternal pressure or rub may be used.)
  3. Eye opening to speech. (Not to be confused with an awaking of a sleeping person; such patients receive a score of 4, not 3.)
  4. Eyes opening spontaneously

Best verbal response (V)

There are 5 grades starting with the most severe:

  1. No verbal response
  2. Incomprehensible sounds. (Moaning but no words.)
  3. Inappropriate words. (Random or exclamatory articulated speech, but no conversational exchange)
  4. Confused. (The patient responds to questions coherently but there is some disorientation and confusion.)
  5. Oriented. (Patient responds coherently and appropriately to questions such as the patient’s name and age, where they are and why, the year, month, etc.)

Best motor response (M)

There are 6 grades starting with the most severe:

  1. No motor response
  2. Extension to pain (adduction of arm, internal rotation of shoulder, pronation of forearm, extension of wrist, decerebrate response)
  3. Abnormal flexion to pain (adduction of arm, internal rotation of shoulder, pronation of forearm, flexion of wrist, decorticate response)
  4. Flexion/Withdrawal to pain (flexion of elbow, supination of forearm, flexion of wrist when supra-orbital pressure applied ; pulls part of body away when nailbed pinched)
  5. Localizes to pain. (Purposeful movements towards painful stimuli; e.g., hand crosses mid-line and gets above clavicle when supra-orbital pressure applied.)
  6. Obeys commands. (The patient does simple things as asked.)

Interpretation

Individual elements as well as the sum of the score are important. Hence, the score is expressed in the form "GCS 9 = E2 V4 M3 at 07:35".

Generally, comas are classified as:

  • Severe, with GCS ≤ 8
  • Moderate, GCS 9 - 12
  • Minor, GCS ≥ 13.

Intubation and severe facial/eye swelling or damage, make it impossible to test the verbal and eye responses. In these circumstances, the score is given as 1 with a modifier attached e.g. 'E1c' where 'c' = closed, or 'V1t' where t = tube. A composite might be 'GCS 5tc'. This would mean, for example, eyes closed because of swelling = 1, intubated = 1, leaving a motor score of 3 for 'abnormal flexion'.

The GCS has limited applicability to children, especially below the age of 36 months (where the verbal performance of even a healthy child would be expected to be poor). Consequently the Paediatric Glasgow Coma Scale, a separate yet closely related scale, was developed for assessing younger children.

Revisions

  • Glasgow Coma Scale: While the 15 point scale is the predominant one in use, this is in fact a modification and is more correctly referred to as the Modified Glasgow Coma Scale. The original scale was a 14 point scale, omitting the category of 'abnormal flexion'. Some centres still use this older scale, but most (including the Glasgow unit where the original work was done) have adopted the modified one.
  • The Rappaport Coma/Near Coma Scale made other changes.

See also

References

  • Teasdale G, Jennett B. Assessment of coma and impaired consciousness. A practical scale. Lancet 1974,2:81-84. PMID 4136544.

External links

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