Anesthetic Methods in the Management of Carotid Endarterectomies Daniel Park MD CA-2 Boston Medical Center

General Anesthesia versus Regional/Local Anesthesia Remains a controversial topic Cochrane review 2004 –7 randomized trials, 41 non-randomized trials –Insufficient evidence to make a clear decision between GA and regional

Regional Anesthesia Deep Cervical Plexus Block –Three separate injections –Line drawn connecting the tip of the mastoid proxess and the Chassaignac tubercle (ie transverse process of C6) –Another line drawn 1 cm posterior to the first line; C2 transverse process lies 1 to 2 cm caudad to the mastoid process –22 G needle x3 advanced perpendicular to the skin and slightly caudad until contacting the transverse process (depth about 1.5 to 3 cm) –If paresthesias elicited, inject 3 to 4 ml of solution, if not elicited, walk along transverse process in a caudad or cephalad direction »OR –Inject in single injection at C4 transverse process and rely on cephalad spread of the anesthetic to C2 and C3 nerves

Regional Anesthesia Deep Cervical Plexus Block Complications –Intravascular injection –Intrathecal injection –Paralysis of the ipsilateral diaphragm –Laryngeal block causing hoarseness, coughing and dysphagia

Regional Anesthesia Superficial Cervical Plexus block –Anesthetize C2 to C4 branches –Midpoint of the posterior border of the sternocleidomastoid muscle –Injection of solution along the posterior border and medial surface of the muscle –May block accessory nerve causing trapezius muscle paralysis

Cerebral Monitoring Why is it important? –Once compromise is discovered (or predicted) carotid shunt can improve cerebral oxygen delivery –Carotid shunt can be placed in both external or internal carotid artery; however internal carotid is much more effective

Cerebral Monitoring Why not shunt everyone? –Potential displacement of atheromatous debris, introduction of air embolism or thrombosis of shunt –Increases surgical time –Presence of shunt makes surgical field less than optimal

Cerebral Monitoring Awake patient the gold standard –Assessment of grip strength of the contralateral hand –Responsive to verbal commands –Same anesthesiologist for assessment in comparison of before and after crossclamping