FRCA Notes

Intra-operative Emergencies in Neurosurgery

Resources

  • May be evidenced by direct observation of brain tissue, raised ICP on neuromonitoring or haemodynamic features

Management

  • Management principles include maintaining CPP, cerebral oxygenation, normothermia, normoglycaemia and reducing CMRO2 e.g. avoid seizures
  • ICP can be reduced in standard fashion:
    • Reduce cerebral blood volume by ensuring adequate venous drainage and elevating the head
    • Control PCO2 to 4.5-5kPa, but temporary reductions to 4.0-4.5kPa may be appropriate
    • Adequate depth of anaesthesia
    • Osmotherapy e.g. hypertonic saline, mannitol
    • Steroids
    • CSF drainage e.g. via EVD

Intra-operative aetiology

  • Cortical stimulation during epilepsy surgery
  • Resection of tumours from frontal or temporal lobe
  • Acute haemorrhage
  • Ischaemia
  • Homeostatic derangements e.g. electrolyte derangement, hypoglycaemia, hypocapnia
  • Drug withdrawal or subtherapeutic anti-epileptic levels

Symptoms

  • The awake patient may demonstrate:
    • Loss of consciousness
    • Focal or generalised motor movements
    • Muscle rigidity
    • Pupillary dilation

  • The anaesthetised, paralysed patient may not demonstrate overt clinical signs of seizure activity
  • There may be tachycardia, hypertension or hypercarbia
  • Processed EEG monitoring may demonstrate seizure activity

Management

  • Prophylactic anticonvulsants in those undergoing surgeries where there is a high risk
  • Immediate intra-operative management:
    • ABCDE
    • Stop causative surgical stimulation
    • Irrigate the surgical site with ice-cold saline to suppress cortical activity
    • Boluses of IV anaesthetic
    • IV benzodiazepines