Abstract ID: A19
Abstract Title: The use of pre-operative ultrasound for carotid bifurcation mapping to aid in determination of optimal anesthetic technique for carotid endarterectomy. A retrospective analysis utilizing database queries against an automated information management system.
Poster Type: Either
ABSTRACT BODY
Carotid endarterectomy is the most frequent vascular surgical procedure performed in the United States. There is a widely held opinion that performance of the procedure under regional anesthesia (RA) is superior for the monitoring of cerebral functioning. Still, RA is sometimes unsuccessful and the case must be converted to general anesthesia (GA). One prominent reason for this is tight cervical retraction against the mastoid and styloid processes. We studied elective carotid endarterectomy under RA or GA using preoperative ultrasound elucidation of the level of carotid artery bifurcation as a major determinant for GA vs. RA. In this series, a high bifurcation, above the angle of the jaw, was considered inappropriate for carotid endarterectomy under RA. It has been our practice that patients were selectively anesthetized with GA if one or more of the following criteria were met: 1) anxiety disorder, 2) claustrophobia, 3) dementia, 4) irradiated neck, or 5) high carotid bifurcation as determined by ultrasound.
IRB approval was obtained to perform a database review. A retrospective analysis was performed by writing Structured Query Language (SQL) queries against our electronic database which is derived from our anesthesia automated information management system. These queries gave counts for the number of carotid endarterectomies based on CPT code for the surgeon of interest. Additionally counts and descriptions of the anesthesia techniques per patient were obtained. When more than one anesthesia type was listed for a patient, the patient's anesthesia record was reviewed.
Two hundred twenty-nine operations were performed from September 2001 to March 2004 using this protocol. Twenty (20) patients were felt to be inappropriate candidates for carotid endarterectomy under RA because of a high bifurcation of the carotid artery as determined by ultrasound, claustrophobia, anxiety disorder, diminished mental status, or irradiated neck. Four (4) patients required conversion to GA due to movement or agitation. Using this approach carotid endarterectomy was successfully accomplished in all patients. Two (2) patients suffered reversible ischemic neurologic deficit in the post-operative period. No patients died in the immediate postoperative period. Average length of stay was twenty-three (23) hours. Two patients ruled in for post-operative myocardial infarction thus prolonging their hospital length of stay. No acute post-operative carotid occlusion or compromise of the airway requiring neck re-exploration occurred
Determination preoperatively of unfavorable cervical anatomy allows for more optimal selection of anesthetic technique and a reduced likelihood of failure of RA. Ninety percent of our carotid revascularizations were performed under RA. The majority of the RAs were superficial cervical plexus blocks. Superficial cervical plexus block provides adequate anesthesia for the procedure without incurring the additional risks of deep cervical plexus block. Pre-operative mapping of the carotid bifurcation readily allowed the identification of individuals with high carotid artery bifurcation. We believe that excluding these individuals from RA increased the probability of success in carotid revascularization under RA.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A19