Does clonidine 50 μg improve cervical plexus block obtained with ropivacaine 150 mg for carotid endarterectomy?: A randomized, double-blinded study

Study Objective: To evaluate the effects of adding 50 pig clonidine to 150 mg ropivacaine for superficial cervical plexus block in patients undergoing elective carotid endarterectomy (TEA). Design: Randomized, double-blind study. Setting: Departments of Anesthesia and Vascular Surgery of a university hospital. Patients: 40 ASA physical status II and III patients undergoing elective TEA during superficial cervical plexus block. Interventions: Superficial cervical plexus block was placed using 20 mL of 0.75% ropivacaine alone (Ropi group, n = 20) or with the addition of 50 mu g clonidine (Ropi-Clonidine group, n = 20). If required, analgesic supplementation was given with local infiltration with 1% lidocaine and intravenous fentanyl (50-mu g boluses). Nerve block profile, need for intraoperative analgesic supplementation, and time to first analgesic request were recorded. Measurements and Main Results: Median (range) onset time was 10 minutes (5-25 min) in the Ropi group and 5 minutes (5-20 min) in the Ropi-Clonidine group (P < 0.05). Intraoperative consumption of both 1% lidocaine and fentanyl was higher in patients of the Ropi group (15 mL [0-25 mL] and 250 mu g [50-300 mu g]) than in patients of the Ropi-Clonidine group (8 mL [0-20 mL] and 0 mu g [0- 150 mu g]; P < 0.05 and P < 0.05, respectively). First postoperative analgesic request occurred after 17 hours (10-24 hrs) in the Ropi group and 20 hours (10-24 hrs) in the Ropi-Clonidine group (P > 0.05). Conclusions: Adding 50 mu g clonidine to 150 mg ropivacaine for superficial cervical plexus block shortened the onset time and improved the quality of surgical anesthesia in patients undergoing elective TEA. (C) 2006 Elsevier Inc. All rights reserved.