Guidelines for Assessing the Glasgow Coma Scale and Pupil Responses in Adults

1. Introduction and Background
2. Patient Assessment
3. The Glasgow Coma Scale
4. Assessment of the Glasgow Coma Scale
5. Pupillary Responses

1. Introduction and Background

Assessment of conscious level is an essential component of neurological examination and is usually performed together with assessment of pupillary size and reaction, vital signs, and focal neurological signs in the limbs. The Glasgow coma scale developed by Teasdale and Jennett (1974) is the most widely used assessment tool to measure a patient's level of consciousness. It is the method favoured by The Leeds Teaching Hospitals NHS Trust and these guidelines have been developed to standardise practice so that the Glasgow coma scale and pupil responses can be assessed in a consistent manner to minimise misinterpretation. The guidelines focus on the practical aspects of carrying out and interpreting the Glasgow coma scale and pupil responses. Recommendations for assessing eye opening, verbal response and motor response are specified.

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2. Patient Assessment

The following are important points to note when assessing a patient's level of consciousness using the Glasgow coma scale and calculating a Glasgow coma score (GCS).

2.1 The arms give a wider range of responses and for this reason are always observed using the Glasgow coma scale. Spinal reflexes may cause the arms/legs to flex briskly in response to pain and must not be interpreted as a response.

2.2 Always record the best arm response. If the motor response is different on each side, the better response is incorporate within the Glasgow coma scale.

2.3 Responses must be recorded on the relevant observation chart in black ink. Changes in a patient's neurologic function, pupil responses, or the GCS must be recorded in relevant nursing documentation including the date, time, and signature.

2.4 As the GCS is an assessment of conscious level, it cannot be determined with accuracy in the patient who is receiving anaesthetic agents; neurological assessment then focuses on pupillary responses.

2.5 Some drugs may affect pupillary reaction and the effects of any prescribed medication must be considered when assessing the pupils.

2.6 A GCS can still be determined in a patient who is sedated although it must be noted that the score obtained might not be an accurate reflection of what the patient is capable of.

2.7 Within the neurosurgical intensive care and high dependency units, a GCS must be assessed at verbal handover/beginning of the shift by both nurses (at the same time) in order to avoid misinterpretation and facilitate continuity.

2.8 When a patient with an impaired level of consciousness is transferred to another ward/department (e.g. recovery, ICU), a GCS must be assessed by both the nurse escorting the patient and the nurse receiving the patient (at the same time) in order to avoid misinterpretation and facilitate continuity of assessment.

2.9 Although the Glasgow coma scale should be communicated using its individual components, a score from 3 to 15 may be used to summarise the scale. A deterioration of one point in the ‘Motor Response' or one point in the ‘Verbal Response' or an overall deterioration of two points in the GCS is of clinical significance and must be reported to medical staff.

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3. The Glasgow Coma Scale

The Glasgow coma scale is based on three aspects of a patient's behaviour - eye opening, verbal response and motor response (see Table 1). A score is applied to each category and totalled to give an overall value ranging from 3 to 15. As well as calculating a total GCS - a score for each of the three components must be calculated and recorded as a separate score.

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4. Assessment of the Glasgow Coma Scale

 4.1 Best eye opening response
If a patient's eyes are closed as a result of swelling or facial fractures this is recorded as ‘C' on the chart. Eye opening is then meaningless under these circumstances.

a. Spontaneous eye opening

It is important to exclude the fact that a patient is asleep before proceeding to assess eye opening.
This is recorded when a patient is observed to be awake with eyes open. This observation is made without any speech or touch. Spontaneous eye opening is allocated a score of 4.

b. Eye opening to speech

If there is no spontaneous eye opening, this is recorded when a patient opens his eyes to loud, clear commands. Eye opening to speech is allocated a score of 3.

c. Eye opening to pain

There is no eye opening to loud, clear commands. Eye opening to pain is recorded when a patient opens his eyes to a painful stimulus: finger tip pressure and supraorbital ridge pressure are the two most commonly used methods of applying a painful stimulus.

These guidelines recommend that eye opening to pain is assessed by applying supraorbital ridge pressure to stimulate the supraorbital nerve, increasing the pressure until a response is obtained.

While critics might argue that supraorbital ridge pressure could cause the patient to grimace and keep the eyes closed, finger tip pressure could lead to misinterpretation of the eye opening response due to other complicating factors such as hemiparesis and high spinal cord injury. Further, the response elicited by finger tip pressure might also be misinterpreted as a motor response, particularly when the problems associated with ‘localising' and ‘withdrawing' to pain are taken into account.

Eye opening to pain is allocated a score of 2.

d. None

This is recorded when no response to a painful stimulus is observed. No eye opening is allocated a score of 1.

A patient with flaccid ocular muscles may lie with his eyes open all the time. This is not a true arousal response and should be recorded as a ‘No Eye Opening' response and allocated a score of 1. It should not be documented as spontaneous eye opening.

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4.2 Best verbal response

If a patient has an endotracheal tube or tracheostomy tube in situ, this is recorded as ‘T' on the chart under ‘No Response' and allocated a score of 1.

If a patient is dysphasic, best verbal response cannot be determined with accuracy. This is recorded as a ‘D' on the chart under ‘No Response' and allocated a score of 1.

a. Orientated

To be classified as orientated, patients must be able to identify:

Who they are
Where they are
The month/year

All three components must be identified correctly for a patient to be classified as orientated. A patient who is fully orientated to time, place and person is allocated a score of 5.

b. Confused

A patient is classified as confused when one or more of the above questions are answered incorrectly. A patient who is confused is allocated a score of 4.

c. Inappropriate words

A patient is classified as using inappropriate words when conversational exchange is absent - there is a tendency to use single words more than sentences. The use of oaths is common. A patient who is using inappropriate words is allocated a score of 3.

d. Incomprehensible sounds

This is recorded when words and speech cannot be identified. A patient may be mumbling, groaning or screaming. A patient who is making incomprehensible sounds is allocated a score of 2.

e. None

The patient does not respond verbally to verbal or physical stimuli. No verbal response is allocated a score of 1.

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4.3 Best motor response

a. Obeys commands

This is recorded when the patient carries out the following command: assessing both sides, the patient is asked to grip and let go of the assessor's fingers. The patient must grip and un-grip to discount a reflex action. If in any doubt, then the patient is asked to raise the eyebrows. A patient who obeys commands is allocated a score of 6.

b. Localises to pain

The patient is unresponsive to verbal commands and is therefore assessed for response to painful stimuli.

It is important to differentiate between localising to pain and flexion to pain as localising is a purposeful response and an indication of better brain function. Flexion is not seen as a purposeful response and may be a reflex action. Supraorbital ridge pressure is considered to be the most reliable and effective technique to distinguish localising from flexion/abnormal flexion as the observed response to this method is less likely to be misinterpreted.

Procedure: a painful stimulus is applied to the supraorbital ridge (to stimulate the supraorbital nerve). In the presence of facial fractures or gross eye swelling, pinching the earlobe is more favourable than applying supraorbital ridge pressure.

To be classified as localising to pain, a patient must move his hand to the point of stimulation, bringing the hand up beyond the chin and across the midline of the body (Figure 1). A patient who is localising to pain is allocated a score of 5.

Figure 1: Localising to painful stimulus

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c. Normal flexion

In a normal flexion response to pain, no localising to pain is seen. This is recorded when in response to a painful stimulus, a patient bends the arms at the elbow (Figure 2). It is a rapid response (likened to withdrawing from touching something hot) and is associated with abduction of the shoulder. A patient who has a flexion response to pain is allocated a score of 4.

Figure 2: Normal flexion response to painful stimulus

d. Abnormal flexion

There is no ‘Normal flexion' to a painful stimulus. It is recorded when in response to a painful stimulus, the patient's elbow flexes. It is characterised by internal rotation and adduction of the shoulder and flexion of the elbow. It is a much slower response than ‘Normal flexion' and may be accompanied by spastic wrist flexion (Figure 3). A patient who has ‘Abnormal flexion' to pain is allocated a score of 3.

Figure 3: Abnormal Flexion response to painful stimulus

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e. Extension to pain

This is recorded when there is no ‘Abnormal flexion' to painful stimulus. A patient presents with straightening of the elbow joint, adduction and internal rotation of the shoulder and inward rotation and spastic flexion of the wrist (Figure 4). A patient who has ‘Extension' to pain is allocated a score of 2.

Figure 4: Extension response to painful stimulus

f. No motor response

This is recorded when there is no response to a painful stimulus. ‘No motor response' is allocated a score of 1.

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5. Pupillary Responses

Focal neurological observations are used to localise cerebral disease to a specific area of the brain while evidence of focal abnormalities may or may not co-exist with evidence of diffuse brain function. Pupil size and reaction to light are important neurological observations.

5.1 Normal pupils

a. Normal pupils are round and equal in size - average size is 2 to 5 mm in diameter.

b. A millimetre scale (as indicated on the neurological observation chart) is used to estimate the size of each pupil.

c. The shape of each pupil should be recorded in the nursing documentation. Abnormal pupil shapes may be described as ovoid, keyhole or irregular.

5.2 Reaction to light

When light is shone into the eye the pupil should constrict immediately. The withdrawal of the light should produce an immediate and brisk dilatation of the pupil. This is called the direct light reflex. Introducing the light into one pupil should cause a similar constriction to occur simultaneously in the other pupil. When the light is withdrawn from one eye, the opposite pupil should dilate simultaneously. This response is called the consensual light reflex.

5.3 Assessment

For the purpose of neurological assessment the size and reaction of the pupils to bright light are recorded.

a. If the pupil reacts briskly to light: record as '+'

b. If the pupil does not react to light: record as '-'

c. If the pupil is sluggish in response when compared to the other pupil: record as ‘S'

d. A sluggish pupil may be difficult to distinguish from a fixed pupil and may be an early focal sign of an expanding intracranial lesion and increased intracranial pressure. A sluggish response to light in a previously reacting pupil must be reported at once to medical staff.

5.4 Procedure

For the purpose of neurological assessment:

a. The pupils should be first observed simultaneously to determine size and equality

b. A bright light is shone into each eye and the result recorded. Any external light source should be eliminated if possible.

c. Pupil responses must always be monitored and recorded in the sedated patient with neurological injury.

d. The shape of the pupil should also be assessed. An ovoid pupil may be an indication of intracranial hypertension.

5.5 Points to note

a. Pinpoint non-reactive pupils are seen with opiate overdose and pontine haemorrhage.

b. The parasympathetic nerve fibres of the 3rd cranial nerve (oculomotor nerve) control constriction of the pupil. Compression of this nerve will result in fixed, dilated pupils.

c. Antimuscarinics dilate the pupil. For example, atropine sulphate 1% (eye drops) has a duration of action of 7 to 12 days after topical application. The effects of intravenous atropine sulphate on the pupil are dose related and higher doses further dilate the pupil. Effects are reversible when therapy is discontinued (AHFS Drug Information, 2004).

d. Non-reactive pupils may also be caused by local damage.

e. One dilated or fixed pupil may be an indication of an expanding/developing intra-cranial lesion, compressing the oculomotor nerve on the same side of the brain as the affected pupil.

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