Major Head And Neck
Injury
This chapter covers patients who have suffered a
significant head (Glasgow Coma Scale; GCS 13) and/or neck injury, often as
part of multi-system trauma (Chapters 8 and 9). Of trauma-related deaths, 70%
are from head injury, and many of these deaths are preventable.
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Primary brain injury occurs at the moment of trauma. Prevention is the
only way to minimise primary injury, which is why collection of injury data is
an integral part of Emergency Medicine. Seatbelts, helmets, car and road design
all prevent primary brain injury, as does road safety enforcement (speeding,
drink driving).
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Secondary brain injury occurs after trauma, and may be preventable by
expert medical care. The most common preventable conditions that cause
secondary brain injury are hypoxia and hypotension.
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Cervical spine injury: in the context of a major head injury, a cervical
spine injury is assumed until proved otherwise. All patients should arrive at
the Emergency Department immobilised on a spinal board with a cervical collar
and supports.
Aside from
an AMPLE history (Chapter 9), information from witnesses may be available from
the ambulance crew. Periods of loss of consciousness and amnesia before or
after the event are helpful to assess neurological damage.
Airway, breathing and cervical
spine
The patient
is immobilised on a spinal board, with a rigid cervical collar, together with
blocks and tape. Immobilisation is painful after about 20 minutes, and pressure
sores can develop in patients with reduced sensation and/or mobility. The
patient should be safely removed from the board as soon as possible, usually as
part of the log roll in the secondary survey.
If a patient
does need to be intubated and ventilated (Chapter 6), it is very important to
establish objective neurological status (see Disability, below) before
intubation, as it is impossible after- wards due to the muscle paralysis
necessary for ventilation.
Circulation
Having
established that the blood will be oxygenated, the next challenge is to ensure
that enough blood is perfusing the brain.
This is
dictated by:
The brain’s
normal self-regulation of CPP is impaired in brain injury: it is critical that
MAP does not fall below 80 mmHg. CPP can be maintained by increasing MAP or
reducing ICP. MAP can be increased by giving intravenous fluids and inotropes
(e.g. adrenaline) according to the CVP and MAP. ICP can be reduced by reducing
venous pressure: avoid excessive intravenous fluid and elevate the head of the
bed by 30°.
Disability
This refers
to the brief structured assessment of functional neurological impairment as a
result of the head injury.
Glasgow Coma Scale
The Glasgow
Coma Scale (GCS) was devised in the 1970s before the advent of CT to predict
the need for neurosurgical intervention. The motor component is the most
important, but also the most difficult to assess. If the GCS is not assessed
using optimal stimula- tion, poor-quality information will be collected,
resulting in poor decisions. Pressing on a fingernail with a pen, and firm
sternal pressure, are commonly used; if a spinal injury is possible, pressure
on the supraorbital nerve in the supraorbital notch is effective.
Pupil size and reactivity
The pupils’
size and reactions give useful information about the patient’s neurological
status, assuming that no drugs that influence the pupil size (e.g. atropine,
adrenaline) have been given.
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If the pupils are of normal diameter (3–5 mm) and reactive, this suggests
underlying normal function, and is associated with a good outcome.
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If one pupil is fixed and dilated, this may indicate that the brain on
the same side is under increased pressure, stretching the IIIrd nerve.
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If both pupils are small, this suggests either opiate overdose or
brainstem injury.
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Having both pupils fixed and dilated is associated with a poor outcome,
unless caused by drugs (e.g. atropine, adrenaline) or local eye injury.
Focal limb movement deficit
If limb
movement differs from one side to the other (excluding direct reasons e.g.
broken arm) consider whether there may be a spinal or brain injury.
Investigations
Any
necessary investigations are integrated into the primary and secondary trauma
survey as described in Chapters 8 and 9.
Bedside investigations
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Blood glucose monitoring must be early and then regularly repeated in all
cases of neurological impairment in the Emergency Department.
Laboratory investigations
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An alcohol level is only useful if negative. If positive it does not rule
out the need for imaging. Some countries have mandatory blood testing for all
road trauma patients.
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FBC/U E/clotting profile/blood group and hold.
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ABGs/lactate ensure accurate assessment of oxygenation, ventilation and
shock.
Imaging
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CT brain and neck.
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MRI is not indicated in the initial assessment, but may be useful to
assess spinal cord injury.
Management
After
stabilisation and CT scan, a decision needs to be made about what further care
is necessary. The process to achieve this depends on local policy, but there
are essentially four groups of patients:
Urgent neurosurgery
This small
but important group comprises patients with extradural (epidural),
intracerebral or posterior fossa bleeding. Some subdural bleeds, e.g. those
resulting in marked midline shift, may also require surgery.
Intensive care
These
patients need a period of ventilation in an ICU, which has facilities for ICP
monitoring using a bolt drilled through the skull, and that offers ready access
to neurosurgery, should this become necessary.
Ward care
Ward care is
for patients who need close neurological monitoring on a normal ward with the
ability to have an urgent medical review should their condition deteriorate. The
Emergency Department observation ward is sometimes used for this group of
patients. Post-injury care including follow-up is advisable, as even patients
with apparent normal function after head injury can have significant problems
(e.g. poor concentration, emotional lability) that are helped by psychological
support.
Catastrophic head injury
If the CT
shows no chance of survival, this must be explained to the patient’s relatives
in sympathetic but unambiguous terms. Organ donation should be sought by a member
of staff experienced at explaining this, as the opportunity to donate organs is
usually very much appreciated in the long term.
