Events

Baseline

  • Prep and baseline recordings should be performed on all patients to rule out any EEG abnormalities that may complicate interpretation

Monitoring

  • Continuous real time electrophysiological feedback on cortical perfusion to determine post op neurological deficits

Manipulation

  • Cross clamping the common carotid artery
  • Temporarily clamping feeding arteries to vascular abnormalities
  • Permanent clipping aneurysm
  • Cortical resection and retraction

Events

  • 50% decrease criteria levels are used to detect global cortical and perfusion changes in passive cortical electrophysiological activity

Closing

  • Monitoring should be continued until undraping
  • Slowly developing perfusion changes can occur

Carotid Endarterectomy

  • To remove atherosclerotic plaque from the carotid artery, which can dislodge ad cause a stroke
  • CEA includes clamping the branches of the carotid artery above and below the plaque so that the material can be surgically removed
  • Because the clamping can produce significant cerebral ischemia, the EEG is used to evaluate collateral perfusion of the brain
    • EEG is also beneficial for detection of hypertension and hypoxia during an CEA
  • Clinical changes occur in about 80% of patients with in 60-90 seconds of cross clamping
  • Most strokes associated with CEA occur after the cross clamp is released
  • Late changes after cross clamping may indicate limited collateral perfusion and an increase in the BP may transiently improve responses, but shunting should still be performed.

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