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 addition of epinephrine as a vasoconstrictor additive to local anesthetic affects the hemodynamic profile after cervical plexus block in patients presenting for carotid endarterectomy.

DESIGN: A prospective, double-blind, randomized trial.

SETTING: A university hospital.

PARTICIPANTS: Forty patients scheduled for carotid endarterectomy under regional anesthesia (cervical plexus block).

INTERVENTIONS: Patients were randomized to one of two groups. Group P (20 patients) received plain bupivacaine; group E (20 patients) received bupivacaine with epinephrine, 5 micrograms/mL. All patients received 2 mg/kg of bupivacaine, and group E received 2 micrograms/kg of epinephrine. The electrocardiogram and intra-arterial blood pressure were monitored continuously, and recordings of heart rate and blood pressure were recorded at predetermined intervals from before the block until the skin incision.

RESULTS: After the block, group 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 plexus block with bupivacaine, the use of epinephrine is associated with an increase in heart rate consistent with a beta-adrenergic effect from systemic absorption of the epinephrine. An increase in systolic blood pressure independent of the use of epinephrine also occurs, but epinephrine appears to mitigate against an increase in diastolic blood pressure.