VOL: 99, ISSUE: 17, PAGE NO: 24
Gail P. Mooney, MSc, PGDip Res Methods, RGN, is lecturer, School of Health Science, University of Wales Swansea;
Dee M. Comerford, MSc, DMS, CertEd, SRN, is clinical nurse specialist in pain control, Carmarthenshire NHS Trust.
Neurological observation is the collection of information on a patient’s central nervous system (consisting of the brain and spinal cord). Both medical practitioners and nurses carry out neurological assessments. They are routinely recorded in A&E and neurological wards, but may also be required in other clinical settings and situations.
Observations are recorded:
To aid with diagnosis of a neurological disorder;
As baseline observations;
Following a neurosurgical procedure;
Medical practitioners carry out a full neurological assessment, which comprises:
The nursing assessment includes level of consciousness, pupillary reaction, motor function and vital signs.
Levels of consciousness
Consciousness can be categorised as:
Full consciousness - the patient is awake, alert and aware of their surroundings;
Drowsiness - the patient responds slowly, sometimes without purpose, to stimuli. They may not verbally respond or, if they do, responses may be incoherent;
Unconsciousness - the patient does not respond to any painful stimuli and is unaware of their surroundings.
A patient’s level of consciousness can deteriorate if there is an underlying problem with the brain due to problems such as head injury, space-occupying lesion (for example, brain tumour), haemorrhage or raised intracranial pressure (ICP). The ICP is determined by the amount of brain tissue, blood and cerebrospinal fluid within the skull, as well as the patient’s position. It is normally ≤15mmHg (Smeltzer and Bare, 1996).
Mallet and Dougherty (2000) recommend that vital signs should be assessed in the following order:
Respirations - the brain controls breathing so any problems with the brain can affect respirations. The rate, depth and pattern of breathing should be recorded;
Temperature - the hypothalamus regulates body temperature, and problems within the hypothalamus will lead to abnormal temperatures;
Blood pressure and pulse - raised blood pressure, bradycardia and a fall in respiratory rate may be indicative of increased ICP. Usually the patient’s level of consciousness will have begun to deteriorate before there is any alteration in the vital signs observation.
Normal pupil size can be anything from 2-6mm in diameter - the average is about 3.5mm (Blows, 2001). A change in pupil size and reaction to light is an indication of raised ICP and compression of the optic nerve.
Initially, it should be noted whether the pupils are of equal size. A pen torch, with a bright narrow beam, should be used to observe the pupils’ reaction to light - each should be tested separately. Rapid constriction is recorded as a positive reaction (+). No constriction is recorded as a negative reaction (-) (Murray, 1998). If the reaction is not brisk it may be described as ‘sluggish’.
Pupil size should also be noted and is usually recorded in the diameter range of 1-9mm. Viney (1996) states that while pupillary response to light does not parallel the depth of coma, it does measure the integrity of the neuronal pathways governing pupil size - reactive pupils indicate that the mid-brain is intact.
The upper limbs are used to assess motor responses since the lower limbs can reflect spinal function - some patients with cerebral dysfunction may have involuntary movements of their limbs (Aucken and Crawford, 1998). The nurse must look for any differences between the right and left side of the body.
There are two types of limb movement:
Flexion is the normal response made when moving the limbs spontaneously or in response to painful stimuli. An extension response - for example, the head extended, jaw clenched shut, arms close to the body with stiffly extended elbows, wrists and fingers flexed, legs stiffly extended, feet plantar flexed - is abnormal (Blows, 2001). This type of movement can be observed without any stimuli being applied (Murray, 1998).
The Glasgow Coma Scale
Over the years, many assessment tools have been developed to improve neurological assessment. The most popular and universally used tool is the Glasgow Coma Scale (GCS), developed in 1974 by Teasdale and Jennett.
The GCS is divided into three sections: eye opening, verbal responses and motor responses. The patient is assessed and scored in each area and the scores are added together to give the patient’s GCS score - the highest possible score is 15; the lowest is 3. A patient who is fully aware and orientated will score 15; a lower score will reflect the patient’s level of consciousness (see Box).
Pupil reaction is not included in the GCS, though it is often incorporated into locally adapted neurological observation charts.
Eye opening - this should be spontaneous when the patient is approached. If the patient’s eyes do not open spontaneously, determine whether they open to speech or painful stimuli. If the eyes are open, do not assume that the patient is fully aware and orientated to their surroundings. Some patients with head injuries may have spontaneous blinking and eye movement; this does not indicate full consciousness (Muxlow, 2000).
Verbal response - this determines state of consciousness. Patients who are fully orientated will know their name, where they are, the date and year. A confused patient may be able to hold a conversation, but when asked questions may give replies which are incorrect or inapt. They may use inappropriate words, which do not make sense to the assessor, or they may make incomprehensible sounds such as moans or groans. Some stimuli may be required to obtain a response from the patient - this type of patient is not aware of their surroundings.
Motor response - this is assessed by giving the patient some simple commands, for example ‘squeeze my hand (both sides)’, ‘lift your legs up off the bed’, and ‘show your tongue’. The strength of the patient’s limbs should be noted - it is essential to observe for weaknesses. When a patient does not respond to simple commands then response to painful stimuli is assessed. There are three recognised stimuli that can be used when assessing motor response:
Trapezium squeeze - use the thumb and two fingers to squeeze and twist the muscle;
Supraorbital pressure - run a finger along the bony rim above the eye. This is not recommended if the patient has facial fractures;
Sternal rub - using the knuckles of a clenched fist, apply pressure along the sternum (Shah, 1999).
The practice of pinching the patient and/or using a pinprick test is no longer recommended for assessing motor response and should not be used during a neurological evaluation.
The advantage of the GCS is that it is widely known and used and provides a standardised assessment of neurological observations. It is simple to use and requires only a pen torch with a bright beam and a copy of the assessment tool. However, Ellis and Cavanagh (cited in Woodrow, 2000) have noted that there may be variations in the recording of pupil size and motor weakness.
Inaccurate and inconsistent recordings could have a detrimental effect on the patient’s well-being and may affect their care plan. Nurses therefore need to be educated in the correct use of the tool, in order to address potential irregularities.
Frequency of neurological assessment
There is no published consensus on how frequently neurological observations should be recorded. One factor which will determine the frequency is the patient’s presenting condition and medical diagnosis. If the patient’s condition is deteriorating, observations may need to be carried out as frequently as every 10-15 minutes. Clinicians’ professional knowledge and judgement will dictate the necessary timing interval for the assessment.
Factors to consider
When assessing neurological status the patient’s medical and nursing notes should first be reviewed, and the medical diagnosis and any other previous symptoms or diseases noted. For example, the patient may have a known neurological disease such as multiple sclerosis, or may have had a previous cerebral vascular accident, both of which could affect the outcome of the assessment. It is also important to note what medications/drugs may have been taken. Some drugs - such as benzodiazepines and opioids - can affect a person’s level of consciousness.
Accurate and consistent recording of neurological observations is essential to establish the patient’s neurological status and to illustrate any changes. Nurses need appropriate training in order to achieve accurate assessment.
The GCS is widely used in the management of patients with actual or potential neurological problems. Nurses play a vital role in the early detection of any change in a patient’s neurological status, and are in a prime position to alert the appropriate medical practitioner to a potentially critical deterioration in the patient’s condition.