TRANSCRANIAL DOPPLER INTRAOPERATIVE MONITORING DURING CAROTID ENDARTERECTOMY - EXPERIENCE WITH REGIONAL OR GENERAL-ANESTHESIA, WITH AND WITHOUT SHUNTING

To determine whether continuous transcranial Doppler (TCD) can signifi cantly alter therapeutic conduct during carotid endarterectomy, a retr ospective study of 117 carotid endarterectomies was done. There was no perioperative mortality; one perioperative stroke was recorded in a p atient who was symptomatic preoperatively. Continuous TCD of the ipsil ateral middle cerebral artery (MCA) was attempted in 99 cases, and suc cessful in 90; nine patients (9.1%) had inadequate temporal windows fo r MCA access. MCA velocities and emboli were recorded before and durin g carotid cross-clamping, and on clamp release. There were no signific ant velocity differences between the patients with regional and genera l anesthesia, and patients with and without carotid shunts, but there was a statistically significant difference in the total number of embo li (air and particulate transients) noted for the shunted and nonshunt ed patients after clamp release: 12.7 versus 23.6, respectively (p = 0 .05). There was no significant difference when particulate and air mic roemboli were compared. During surgery TCD identified residual flow of less than 40% in the MCA in 17 patients (18.8%). TCD also identified hyperperfusion in two patients, shunt abnormalities in three patients, and influenced postop treatment in four patients, one of whom was ret urned to surgery. TCD is an important tool for identifying patients wh o would benefit from a shunt, preventing hyperperfusion, identifying p ostop emboli, and detecting technical errors.