The Addition of Fentanyl to Local Anesthetics Affects the Quality and Duration of Cervical Plexus Block

Abstract

Cervical plexus block is frequently associated with unsatisfactory sensory blockade. In this randomized, double-blind, placebo-controlled trial, we examined whether the addition of fentanyl to local anesthetics improves the quality of cervical plexus block in patients undergoing carotid endarterectomy (CEA). Seventy-seven consecutive adult patients scheduled for elective CEA were randomized to receive either fentanyl 1 mL (50 microg) or saline placebo 1 mL in a mixture of 10 mL bupivacaine 0.5% and 4 mL lidocaine 2% for deep cervical plexus block. Superficial cervical plexus block was performed using a mixture of 10 mL bupivacaine 0.5% and 5 mL lidocaine 2%. Pain was assessed using the verbal rating scale (0-10; 0 = no pain, 10 = worst pain imaginable), and propofol in 20-mg IV bolus doses was given to patients reporting verbal rating scale >3 during the procedure. Rescue medication consumption during surgery and analgesia requirements over the next 24 hours, as well as onset of sensory blockade, were recorded. A P value <0.05 was regarded as statistically significant. Fewer patients in the fentanyl group (4 of 38, 10.5%) required propofol compared with the placebo group (26 of 39, 66.7%; P < 0.001). In comparison with the placebo group, the fentanyl group consumed less propofol (median 0 [0-60] vs 60 [0-160] mg, respectively; P < 0.001), required postoperative analgesia less frequently (22 of 38 patients, 57.9% vs 35 of 39 patients, 89.7%, respectively; P = 0.002), and requested the first analgesic after surgery later (median 5.8 [1.9-15.6] vs 3.1 [1.0-11.7] hours, respectively; P < 0.001), whereas the onset time of sensory blockade was similar in both groups (median 12 [9-18] vs 15 [9-18] minutes, respectively; P = 0.18). The addition of fentanyl to local anesthetics improved the quality and prolonged the duration of cervical plexus block in patients undergoing CEA.