A patient's conscious level indicates their degree of wakefulness and awareness of their environment. Any impairment suggests underlying brain dysfunction.

All patients with an altered conscious level are at risk of airway obstruction. This is because the brain controls the muscles which normally hold the tongue in a forward position and once the patient becomes deeply unconscious the tongue falls uncontrollably back and causes a partial or complete obstruction. The unconscious patient is also at risk of aspiration, when the acidic contents of the stomach regurgitates and spills into the trachea. This could result from passive aspiration, or during active vomiting, and causes a major threat of sudden hypoxia, and aspiration pneumonia.

A reduced conscious level could come from inside the brain (primary causes) or as a consequence of something unstable within the body (secondary causes).

Some of these causes are reversible using the ABCDE approach; others will require medical treatments in addition to this, such as Naloxone for example if the patient has received an opiate overdose.

The main purpose is to judge how effectively the brain is getting blood flow, cerebral perfusion, and how that is affecting consciousness, orientation and limb movement.

Interaction with the patient is the key to judging deficit. This will enable you to assess the conscious level and whether the patient coherently responds to the environment around them. It is useful if you have been caring for the patient in the previous hours or days as this will help you compare the degree of deterioration, but this maybe your first experience of the patient.

A(C)VPU

The first is the easiest but simplest method called A(C)VPU. It is a basic and quick tool.

What am I looking for in a patient?

• Alert - opens eyes spontaneously. This is normal.

• New Confusion or agitation - an acute change from the patient's 'normal' mental status. A patient who is normally confused, for example due to dementia, and is behaving normally for themselves would not be classed as confused, but a patient who is displaying new or worse confusion or agitation would be classed as newly confused.

• Voice - opens eyes, makes a noise or moves when you speak and goes back to sleep during or after the time you are speaking. This is a growing concern.

• Pain - responds to painful stimuli. May open their eyes, make a noise or withdraw their limbs, grimace or try to resist the painful stimuli.

• Unresponsive - totally unresponsive, despite voice or painful stimuli.

(Royal College of Physicians 2017)

If a patient only responds to pain or is unresponsive there is a major threat to the airway and breathing. This patient should always be referred to anaesthetic care, unless senior doctors have decided that the patient is not suitable for further escalation of care. In this case, good airway protection and respiratory management can still be used within the limits of ward care.

A(C)VPU is used within the NEWS2 scoring system as part of the ABCDE assessment. New confusion has been added because it is often a significant indicator of deterioration or infection. Patients may not recognise their family, surroundings, know the month and year or could be distressed and agitated, trying to climb out of bed. The family, a useful resource to normal behaviour, will often tell you that this is completely out of character (Royal College of Physicians 2020).

Glasgow Coma Scale

Glasgow Coma Scale (GCS) is used to assess a patient's level of consciousness by observing their ability to open their eyes (eye opening), answer questions (verbal response) and move their limbs (motor response). The scale allows the nurse to make rapid, repeated evaluations of the patient's neurological condition. Each response carries a numerical value that closely correlates with the patient's best level of responsiveness. The highest possible score is 15 reflecting somebody who is fully alert and orientated. The lowest possible score is 3 indicating no verbal response (E1), no verbal response (V1) and no movement in response to painful stimulus (M1) The nurse should monitor the patient vigilantly and report any changes to the medical staff.

GCS uses similar methods to those used for AVPU. Eye opening evaluates the patient's level of wakefulness thereby assessing the integrity of the brain stem. If there is no response a peripheral pain stimulus is used (e.g. applying pressure with increasing intensity, to the side of the finger nail for a maximum of 10-15 seconds.

Verbal response assesses the function of the speech areas in the temporal/frontal lobes by asking a series of questions relating to the patient's personal details (i.e. date of birth, where they are and the year and month. Motor response assesses the area in the brain that controls movement. If the patient is unable to obey commands, a central painful stimulus (supra-orbital ridge pressure or the trapezius muscle), observing the best level of response from the arms

The patient who unnaturally flexes as a response to painful stimuli will draw arms inwards, bending at the elbows and raising the arms towards the chin; the fists may clench and rotate (decorticate posturing). The second type of unnatural movement sees the patient go into extension. The whole body becomes rigid, the teeth often clench, arms and leg stretch down the length of the body. The hands rotate outwards so that the palms are facing away from the body and the toes point downwards. This is called decerebrate posturing and reflects damage to the brainstem.

Pupil Reaction

Performed alongside GCS is Pupil Reaction. This needs to be viewed from a position where the nurse can see both eyes for comparison. You are looking for regularity in all aspects; size, shape and reaction, unless the patient is known to have differences. In order to check this, an appropriate bright light (pen torch) is shone into each eye to see the speed of the pupils' closure, constriction. This is known as the pupillary reflex and is a brainstem reaction.

Each eye must be checked, and then the eyes viewed together to ensure similarity. The pupils may differ in size, with one becoming larger than the other – a unilateral dilated pupil. This is indicative of pressure from one side of the brain, and requires an urgent medical review with further investigation. In the worst case, the pupils become fixed and dilated demonstrating that the patient has ‘coned', a term used to describe herniation during which the brainstem has been squeezed through the Foramen Magnum at the base of the skull. This is a terminal sign.

The final assessment is the measurement of blood glucose through finger prick point of care testing. The brain relies upon glucose as the energy source but is unable to store it. As a result the brain relies on a good source from the bloodstream. Hypoglycaemia is dangerous to the brain, and the patient will become unconscious. If the blood glucose is found to be low (below 3 mmol/l) 2.5-5mls per kilogram of 10% glucose should be given as an infusion. Alternatively a bolus of 25-50 ml glucose 10% should be prescribed and given immediately. This should be administered via a large peripheral cannula, with a flush of saline before and afterwards because it is a thick solution and a potential irritant. The effect can be dramatic and the patient can wake quickly, but continue to monitor the blood sugar regularly, and check the patient frequently until stability is gained. The reason for the hypoglycaemic episode should be explored as this may be completely unexpected.

Treatment of a reduced conscious level involves firstly reviewing what you have already done for ABC as airway breathing and circulation problems can all be causes of reduced conscious level. Ensure the airway is open and that the patient is receiving 100% oxygen. Ensure perfusion is adequate and treat hypotension with fluid challenges. If the patient only responds to voice or is unresponsive they should be turned into the recovery position so the airway remains open and in the event of vomiting, the gastric contents will drain from the mouth rather than be inhaled and aspirated. Someone must remain with the patient at all times and vigilantly watch for signs of impaired breathing and circulation.

Ongoing vigilant monitoring of the brain must be undertaken accurately and repeatedly for the earliest detection of deterioration. Assess AVPU, GCS and pupil reaction and check blood glucose, treating hypoglycaemia if found.

Deterioration in the patient's condition may require urgent investigation such as a lumbar puncture, a procedure to remove a sample of spinal fluid for analysis, or a CT scan of the Head. Thorough, rapid planning is required as the patient will require safe transfer through this process, as movement immediately makes the patient vulnerable to further deterioration. As a consequence the patient must be accompanied by the most appropriate people and equipment.

The staff accompanying the patient to CT scanner must be experienced and be able to deal with any deterioration, such as resuscitation. An Anaesthetist should be asked to review the patient as they may need to be intubated before transfer in order to control the airway whilst the patient is kept still, supine and asleep for the scan. Secondly, the right equipment needs to travel with the patient. This includes oxygen, infusions and monitoring devices, such as the Dynamap so care is seamless. You may need to take a supply of fluids and emergency drugs with you as well.

• Royal College of Physicians (2017) National Early Warning Score (NEWS) 2. Retrieved from https://www.rcplondon.ac.uk/projects/outputs/national-early-warning-score-news-2

• Royal College of Physicians (2020) NEWS2: Additional implementation guidance. Retrieved from https://www.rcplondon.ac.uk/projects/outputs/news2-additional-implementation-guidance