The effects of carotid sinus nerve blockade on hemodynamic stability after carotid endarterectomy

Abstract

Objective : To determine whether intraoperative administration of bupivacaine reduces the incidence of hypotension after carotid endarterectomy (CEA). Design : Prospective, double-blinded, randomized controlled trial. Setting : A single-institute, tertiary-care medical center. Participants : Patients ( n = 135) who were referred for CEA without prior ipsilateral CEA, diabetes mellitus, or allergies to local anesthetics. Interventions : 2 mL of 0.25% bupivacaine or 2 mL NaCl (control) injected by the surgeon at the carotid sinus immediately after CEA. Measurements and Main Results : Blood pressure and heart rate were measured before induction, before carotid reperfusion, 2 minutes after reperfusion, before carotid sinus injection, and every 15 minutes thereafter for 2 hours. Anesthesia was induced and maintained with fentanyl, pancuronium, and 0.5% to 1% enflurane. Hypertension was defined as a systolic blood pressure 30% above baseline or greater than 180 mmHg. Hypotension was defined as a systolic blood pressure 30% below baseline or less than 100 mmHg. Postoperative incidences of hypertension, hypotension, and the associated use of corrective medications were compared in both groups using the chi-squared test to determine statistical significance. Patients in the bupivacaine group ( n = 61) had a similar incidence of postoperative hypotension as controls ( n = 74) but a higher incidence of hypertension (40% v 24%; p = 0.043). The bupivacaine group required vasodilators more often (33% v 18%; p = 0.04). Baseline hypertension and preoperative use of β-blockers also were predictive of postoperative hypertension. Conclusions : Carotid sinus area infiltration with bupivacaine after CEA does not reduce the incidence of postoperative hypotension but significantly increases the incidence of postoperative hypertension. Thus, its routine use cannot be recommended in carotid endarterectomy.