Converting from General Anesthesia to Cervical Block Anesthesia for Carotid Endarterectomy

Abstract

Between January 1, 1992 and June 30, 1998, vascular and general surgery residents performed 401 carotid endarterectomies (185 cervical block, 216 general anesthesia) under supervision of vascular attending surgeons. In January 1995, cervical block anesthesia was newly instituted. Initially anesthesiologists were randomly assigned to these cases and anesthetic technique was not standardized. At the surgeons' insistence later in the series, three specially trained anesthesiologists routinely administered cervical block anesthesia. As experience grew, surgeons realized that operating time greater than 2 hours and high neck dissections requiring mandibular retraction were poorly tolerated by cervical block anesthesia patients but that repeat carotid endarterectomies could be safely performed. Shunts were selectively inserted if significant electroencephalographic changes occurred or carotid stump pressures were less than 50 mm Hg systolic when general anesthesia was used; neurologic changes occurred when cervical block anesthesia was used; or there was a history of ipsilateral stroke for either anesthetic method.

Despite an initial learning curve with cervical block anesthesia, the stroke-mortality rate was similar between the two groups (general anesthesia: 1.9% [four cerebrovascular accidents, two deaths]; cervical block anesthesia: 1.6% [two cerebrovascular accidents, two deaths]). Eight (12%) of the first 66 cervical block anesthesia patients were converted to general anesthesia compared to 2 (1.7%) of the most recent 119 patients with cervical block anesthesia (p=0.03). After cervical block anesthesia was initiated, seven of the first eight repeat carotid endarterectomies were performed using general anesthesia compared to one of the most recent six repeat cases (p=0.02). As surgeons' comfort with cervical block anesthesia increased, 94% (100) of the most recent consecutive 106 carotid endarterectomies were performed using this technique.

These results suggest that carotid endarterectomy can be performed as safely using cervical block anesthesia as general anesthesia, specialized anesthesiologists are essential to achieve a successful outcome, selected repeat carotid endarterectomies can be performed using cervical block anesthesia, very cephalad lesions are best treated using general anesthesia, and surgical trainees can safely perform carotid endarterectomy under attending surgeon supervision if the operation is carried out expeditiously.