Question 28

Last updated Fri, 04/28/2017 - 17:41
 Topic: Neurology and Neurosurgery
Pass rate
34%
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A 27-year-old male presents with a severe head injury (GCS 4 at the scene), sustained in a high-speed motor vehicle collision. His initial CT scan in the emergency department shows a 2x3x2.5cm frontal haemorrhagic contusion and diffuse oedema. He is taken directly to the operating theatre where an external ventricular drain (EVD) is inserted. The patient is settled into the ICU and his secondary survey does not reveal any other significant injuries. The initial ICP is 32 mmHg after the EVD is connected.


a) If the ICP is refractory to your initial management of sedation, paralysis and correct positioning, what further measures will you consider and why?

b) What are the risk factors for post-traumatic seizures in patients with traumatic brain injury?

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College Answer

a) If the ICP is refractory to your initial management of sedation, paralysis and correct
positioning, what further measures will you consider and why?

  • Ensure EVD patent and CSF draining (reduce CSF component of ICP)
  • Measures to maintain CPP > 60 mmHg
    • Fluids (avoid albumin – SAFE TBI)
    • Vasopressors
  • Repeat CT scan to exclude a new mass lesion
  • Osmotherapy (hypertonic saline or mannitol)
    • Goal Na+ 150, Osm 300-320
  • Consider barbiturates or propofol (decrease CMRO2)
  • Consider continuous paralysis (decrease CMRO2)
  • Consider moderate hypothermia (decrease CMRO2 and potentially neuroprotective)
    • Adverse outcome in paediatric TBI RCT from CCCTG
    • McIntyre MA suggesting titrated to ICP and prolonged duration may be beneficial
    • Ongoing trials including POLAR in ANZ
  • Decompressive craniotomy is contentious
    • DECRA showed decreased ICP and reduced ICU length of stay but no mortality benefit and a greater number of patients with an unfavourable neurological outcome in those who received decompressive craniectomy.
    • Patients with mass lesions (unless too small to require surgery) were excluded so this patient may not have been included in the study.
    • Only a single surgical intervention was used.

b) What are the risk factors for post-traumatic seizures in patients with traumatic brain injury?

  • GCS < 10
  • Cortical contusion
  • Depressed skull fracture
  • Subdural, epidural or intracerebral haematoma
  • Penetrating head wound
  • Seizure within 24 hours of injury
 

Discussion

This question interrogates the candidate's familiarity with the more outré methods of decreasing a person's intracranial pressure.

Lets face it, anybody can sedate, paralyse and position the patient. Those measures are basic.

a)What further measures will you consider and why?

The Brain Trauma Organisation Guidelines for Management Traumatic Brain Injury contain a set of guidelines, which I have mindlessly parroted here.

Ultimately, there is an escalating series of management strategies which are standard for this scenario.

Control ICP by immediate measures:

  • Open EVD to drain CSF
  • Osmotherapy
    • Hypertonic saline to keep Na+ around 150
    • Consider intermittent mannitol
  • Consider paralysis

Exclude new intracranial pathology:

  • CT brain

Maintain cerebral oxygen supply:

  • Normoxia
  • Normotension (CPP >60mmHg) - maintained with fluids or vasopressors
  • Monitor cerebral oxygenation, keep the SjO2 >50%

Decrease cerebral oxygen demand:

  • Sedate with propofol
  • Ensure adequate analgesia
  • Consider barbiturate coma
  • Consider hypothermia

Discuss a decompressive craniotomy with the neurosurgeon.

b) The risk factors for post-traumatic seizures

This answer was taken directly from the Brain Trauma Organisation Guidelines for Management Traumatic Brain Injury. Word for word, in fact; copy and paste. See it here.

I will reproduce them here for ease of reference;

  • Glasgow Coma Scale (GCS) Score < 10
  • Cortical contusion
  • Depressed skull fracture
  • Subdural hematoma
  • Epidural hematoma
  • Intracerebral hematoma
  • Penetrating head wound
  • Seizure within 24 h of injury

I should probably also digress for a moment to discuss the duration of seizure prophylaxis (the Brain Trauma Foundation recommends no more than 1 week). Post-traumatic seizure management is well covered elsewhere.

References

 

Oh's Intensive Care manual:

Chapter 43 (pp. 563) Cerebral protection by Victoria Heaviside and Michelle Hayes, and

Chapter 67 (pp. 765) Severe head injury by John A Myburgh.

Brain Trauma Organisation Guidelines for Management Traumatic Brain Injury is the definitive source.

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