Carotid endarterectomy: Intraoperative monitoring of cerebral perfusion

Abstract

Carotid endarterectomy (CEA) is a commonly performed surgical procedure aiming to relieve the neurological symptoms of carotid artery atherosclerosis and to prevent embolic stroke. There is unequivocal evidence to support CEA in both symptomatic and asymptomatic patients with certain degrees of carotid artery stenosis and the operation is increasingly performed early following neurological symptoms. One of the goals for the anaesthetist during CEA is to protect the brain from ischaemic injury. The brain is particularly susceptible to ischaemic insult during carotid cross-clamping and therefore the anaesthetist and surgeon must be able to detect significant falls in cerebral perfusion and intervene appropriately. The commonest intervention in this situation is the insertion of a surgical shunt, which is not without associated risk. Several methods exist for monitoring cerebral perfusion during CEA although the ideal method has yet to be determined as none is perfect. Techniques available include continuous clinical assessment in the awake patient, electroencephalography (EEG), somatosensory evoked potentials (SSEPs), transcranial Doppler (TCD), near infrared spectroscopy (NIRS), xenon blood flow and internal carotid artery stump pressure monitoring.