Effective low dosage of mepivacaine in ultrasound-guided axillary nerve block: a double-blinded, randomized clinical trial of efficacy in patients undergoing distal upper extremity surgery

Published in J Clin Anesth. 2014 May;26(3):222-6

Authors: Perov S et al

STUDY OBJECTIVE:

To evaluate two low-dose volumes (20 mL or 30 mL) of 1.5% mepivacaine solution used for ultrasound-guided axillary blockade for outpatients undergoing distal upper limb surgery.

DESIGN:

Prospective, double-blinded randomized study.

SETTING:

Outpatient surgical setting of a university-affiliated hospital.

PATIENTS:

64 adult, ASA physical status 1, 2, and 3 patients, aged 28-46 years, scheduled for upper limb surgery.

INTERVENTIONS:

Patients were randomized to two groups to receive either 20 mL of 1.5% mepivacaine solution (n=31) or 30 mL of 1.5% mepivacaine solution (n=33) for ultrasound-guided axillary plexus blockade.

MEASUREMENTS:

Block duration, proportion of surgical and functional successful blocks, onset of sensory and motor blockade measured from 0 to 30 minutes following final needle extraction, total amount of preoperative sedative (midazolam), and intraoperative propofol administered were recorded.

MAIN RESULTS:

Following axillary plexus blockade, neither patient group showed any statistically significant difference in the percentage of functionally successful blockade (30 mL, 100%: 20 mL, 97%; P = 0.48), surgically successful blockade (30 mL, 100%; 20 mL, 94%; P = 0.23), cumulative sensory or motor blockade surgical time, block performance time, preoperative midazolam use, or intraoperative propofol use.

CONCLUSION:

Low volumes (30 mL or 20 mL) of 1.5% mepivacaine provides satisfactory anesthesia for ambulatory distal upper limb surgery with no significant difference in clinical outcomes.