Neurological assessment Part 3 - Glasgow Coma Scale

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Author
Phil Jevon, PGCE, BSc, RGN, is resuscitation officer/clinical skills lead, honorary clinical lecturer, Manor Hospital, Walsall.

Nursing Times; 104: 29, 28-29.

The Glasgow Coma Scale (GCS) is used to assess level of consciousness in a wide variety of clinical settings, particularly for patients with head injuries (NICE, 2007). In this practical procedure, assessment of the patient's best eye-opening response will be outlined and discussed, and, in next week's article, assessment of the patient's best verbal and motor responses will be described.

What the GCS assesses

The GCS assesses the two aspects of consciousness:

• Arousal or wakefulness: being aware of the environment;

• Awareness: demonstrating an understanding of what has been said.

The 15-point scale assesses the patient's level of consciousness by evaluating three behavioural responses:

• Eye opening;

• Verbal response;

• Motor response.

Eye opening

Assessment of eye opening involves the evaluation of arousal (being aware of the environment):

• Score 4: eyes open spontaneously;

• Score 3: eyes open to speech;

• Score 2: eyes open in response to pain only, for example trapezium squeeze (caution if applying a painful stimulus);

• Score 1: eyes do not open to verbal or painful stimuli.

• Record 'C' if the patient is unable to open her or his eyes because of swelling, ptosis (drooping of the upper eye lid) or a dressing.

Verbal response

Assessment involves evaluating awareness:

• Score 5: orientated;

• Score 4: confused;

• Score 3: inappropriate words;

• Score 2: incomprehensible sounds;

• Score 1: no response. This is despite both verbal and physical stimuli.

• Record 'D' if the patient is dysphasic and 'T' if the patient has a tracheal or tracheostomy tube in situ.

Motor response

Assessment of motor response is designed to determine the patient's ability to obey a command and to localise, and to withdraw or assume abnormal body positions, in response to a painful stimulus (Adam and Osborne, 2005):

• Score 6: obeys commands. The patient can perform two different movements;

• Score 5: localises to central pain. The patient does not respond to a verbal stimulus but purposely moves an arm to remove
  the cause of a central painful stimulus;

• Score 4: withdraws from pain. The patient flexes or bends the arm towards the source of the pain but fails to locate the source of the pain (no wrist rotation);

• Score 3: flexion to pain. The patient flexes or bends the arm; characterised by internal rotation and adduction of the shoulder and flexion of the elbow, much slower than normal flexion;

• Score 2: extension to pain. The patient extends the arm by straightening the elbow and may be associated with internal shoulder and wrist rotation;

• Score 1: no response to painful stimuli.

Painful stimulus

A true localising response to pain involves the patient bringing an arm up to chin level. Painful stimuli that can elicit this response include trapezium squeeze (Fig 4), suborbital ridge pressure (Fig 5) (not recommended if there is a suspected/confirmed facial fracture) and sternal rub (caution, not recommended in some organisations) (Fig 6) (Jevon, 2007).

The procedure

• Explain the procedure to the patient.

• Ascertain the patient's acuity of hearing.

• Ideally, use an interpreter if the patient does not speak English.

• Check the patient's notes for any medical condition that may affect the accuracy of the GCS, for example previous stroke, affecting the movement of the patient's arms (Fig 1).

• Check the neurological observation chart for the GCS scale (Fig 2).

• Check if the patient opens their eyes without the need to speak or to touch them; if the patient does, then the score is 4E.

• If the patient does not open their eyes, talk to them (Fig 3). Start off with a normal volume and speak louder if necessary. If they now open their eyes, the score is 3E.

• If the patient does not open their eyes to speech, administer a painful stimuli, for example trapezium squeeze (using the thumb and two fingers grasp the trapezius muscle where the neck meets the shoulder and twist ) (Fig 4). Or apply suborbital pressure (locate the notch on the suborbital margin and apply pressure to it) (Fig 5). An alternative is the sternal rub (using the knuckles of a clenched fist to apply grinding pressure to the sternum; not recommended for repeated assessment) (Fig 6).

• If the patient opens their eyes to a painful stimulus record the score as 2E (Dougherty and Lister, 2005). If the patient does not respond, then the score is 1E.

References

Adam, S., Osborne, S. (2005) Critical Care Nursing Science and Practice (2nd ed). Oxford: Oxford University Press.

Dougherty, L., Lister, S. (2005) The Royal Marsden Hospital Manual of Clinical Nursing Procedures (6th ed). Oxford: Blackwell Publishing.

Jevon, P. (2007) Treating the Critical Care Patient. Oxford: Blackwell Publishing.

NICE (2007) Head Injury: Triage, Assessment, Investigation and Early Management of Head Injury in Infants, Children and Adults. www.nice.org.uk56

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