Score Eye opening
Best motor response
Best verbal response
• confused conversation - 4
• inappropriate words - 3
• incomprehensible sounds - 2
Any patient with a GCS of 8 or less will have reduced airway reflexes and a high risk of aspiration. These patients, and those in whom the GCS falls by more than 2 points, should be referred to the ICU, if appropriate, as they will almost certainly require intubation.
In non-trauma patients who have been unconscious for 6 hours:
• 40% will have taken some form of sedative
• 40% have hypoxic brain injury (for example, following cardiac arrest)
• 30% have a cerebrovascular cause (infarct or haemorrhage)
Because hypoxic brain injury and stroke are by far the most common causes of non-traumatic coma, it is not surprising that 23% of these patients die within 1 hour, 64% within 1 week, 76% within 1 month, and 88% within 1 year.
Traumatic brain injury (TBI) is common and is the leading killer and cause of disability in children and young adults. Most research on brain injury and brain protection has been done in TBI but the principles are the same for all brain injury, whether caused by trauma or not.
There are many different causes of an unconscious patient and there is sometimes no history. A systematic approach is therefore required. Unconscious patients should always be considered an emergency. A, B, C, D, E is the system used to assess them:
• A - ensure patent, safe airway and treat if needed
• B - ensure adequate breathing and treat if needed
• C - assess circulation and treat if needed
• D - assess disability. The simple AVPU scale can be used at first, but the Glasgow Coma score should also be recorded so that any later changes can be documented precisely
• E - expose and examine the patient fully once A, B, and C is stable. Certain clusters of signs may point to a particular diagnosis
• While all this is going on, request a bedside glucose measurement.
Patients with focal neurological signs but no meningism are likely to have a stroke or tumour. Patients with meningism are likely to have meningitis or subarachnoid haemorrhage. Patients with neither focal signs nor meningism are likely to have hypoxic brain injury, intoxication, metabolic problems, severe sepsis, hypothermia, or epilepsy (non-convulsive status epilepticus is unusual, but one-fifth of patients with status may not appear to be convulsing).
The diagnosis and deliberation must not delay the need to actively treat A, B, C. In meningococcal meningitis securing the airway, and administering oxygen and intravenous fluid could save the patient's life more quickly than antibiotics (although in practice these are given together). Indications for intubation in brain injury, if appropriate, are:
• loss of protective laryngeal reflexes from any cause
• ventilatory insufficiency (hypoxaemia or hypercapnia)
• spontaneous hyperventilation causing a low CO2
• respiratory arrhythmia
• in certain situations where patients may need intubation prior to transfer (significantly deteriorating conscious level, bilateral fractured mandible, bleeding into the airway, or seizures).
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