COMPARATIVE EFFECTS OF PLAIN AND EPINEPHRINE-CONTAINING BUPIVACAINE ON THE HEMODYNAMIC-RESPONSE TO CERVICAL PLEXUS ANESTHESIA IN PATIENTS UNDERGOING CAROTID ENDARTERECTOMY

Objectives: This study was designed to investigate whether the additio n of epinephrine as a vasoconstrictor additive to local anesthetic aff ects the hemodynamic profile after cervical plexus block in patients p resenting for carotid endarterectomy. Design: A prospective, double-bl ind, randomized trial. Setting: A university hospital. Participants: F orty patients scheduled for carotid endarterectomy under regional anes thesia (cervical plexus block). Interventions: Patients were randomize d to one of two groups. Group P (20 patients) received plain bupivacai ne; group E (20 patients) received bupivacaine with epinephrine, 5 mu g/mL. All patients received 2 mg/kg of bupivacaine, and group E receiv ed 2 mu g/kg of epinephrine. The electrocardiogram and intra-arterial blood pressure were monitored continuously, and recordings of heart ra te and blood pressure were recorded at predetermined intervals from be fore the block until the skin incision. Results: After the block, grou p E developed a sustained increase in heart rate of approximately 15% (p < 0.01), whereas group P showed no change. Systolic blood pressure increased significantly with time over the study period in both groups (p < 0.01). Diastolic blood pressure increased significantly in group P (p < 0.01) but not in group E. Conclusions: Concerning cervical ple xus block with bupivacaine, the use of epinephrine is associated with an increase in heart rate consistent with a beta-adrenergic effect fro m systemic absorption of the epinephrine. An increase in systolic bloo d pressure independent of the use of epinephrine also occurs, but epin ephrine appears to mitigate against an increase in diastolic blood pre ssure. Copyright (C) 1996 by W.B. Saunders Company