Cerebral hemodynamic changes and electroencephalography during carotid endarterectomy

Area of Science:

• Neurology
• Vascular Surgery
• Anesthesiology

Background:

• Patients undergoing carotid endarterectomy face risks of brain ischemia during arterial cross-clamping.
• Cerebral blood flow (CBF) monitoring is crucial for assessing neurological compromise during the procedure.

Purpose of the Study:

• To evaluate changes in CBF using an intravenous (IV) 133Xenon technique.
• To correlate CBF alterations with electroencephalogram (EEG) changes during carotid artery cross-clamping.

Main Methods:

• CBF was measured in 15 patients before anesthesia, during cross-clamping, post-release, and 24 hours post-operation.
• Electroencephalogram (EEG) was continuously monitored throughout the surgery.
• Patients received anesthesia with methohexitone, fentanyl, and nitrous oxide/oxygen; carotid shunts were not utilized.

Main Results:

• In 8 patients, cross-clamping did not affect EEG; anesthesia decreased CBF by 38%, with no further changes during clamping.
• In 7 patients, EEG deterioration occurred during cross-clamping, associated with a 33% CBF decrease; anesthesia did not alter CBF.
• A direct correlation was observed between the severity of EEG changes and the magnitude of CBF reduction during cross-clamping.

Conclusions:

• Anesthesia-induced CBF reduction is a normal response, but lack of change suggests underlying cerebrovascular disease.
• Significant CBF decrease during cross-clamping, especially with EEG changes, indicates compromised cerebrovascular reserve and potential ischemia risk.
• These findings highlight the importance of monitoring CBF and EEG to identify patients at risk during carotid endarterectomy.