Major Head And Neck Injury - pediagenosis
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Wednesday, June 19, 2019

Major Head And Neck Injury

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.

   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).
   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.
   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.

Major Head And Neck Injury

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.

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°.

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.
   If the pupils are of normal diameter (3–5 mm) and reactive, this suggests underlying normal function, and is associated with a good outcome.
   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.
   If both pupils are small, this suggests either opiate overdose or brainstem injury.
   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.

Any necessary investigations are integrated into the primary and secondary trauma survey as described in Chapters 8 and 9.

Bedside investigations
   Blood glucose monitoring must be early and then regularly repeated in all cases of neurological impairment in the Emergency Department.

Laboratory investigations
   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.
   FBC/U  E/clotting profile/blood group and hold.
   ABGs/lactate ensure accurate assessment of oxygenation, ventilation and shock.

   CT brain and neck.
   MRI is not indicated in the initial assessment, but may be useful to assess spinal cord injury.

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.

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