The effects of Different Concentrations and Equivalent Volumes of Levobupivacaine in Epidural Anesthesia

BACKGROUND: Levobupivacaine, the S(-) isomer of bupivacaine, is less cardiotoxic than racemic bupivacaine. Previous studies have examined different concentrations of levobupivacaine in similar ways. OBJECTIVES: This prospective, randomized, double-blind study was designed to determine the clinical efficacy and hemodynamic effects of different concentrations and equivalent volumes of levobupivacaine in epidural anesthesia. To our knowledge, this is the first study to evaluate the effects of concentration lower than 0.5% levobupivacaine. METHODS: Forty adult patients with an American Society of Anesthesiology (ASA) I-III physical status undergoing transurethral endoscopic surgery were randomly divided into 2 groups to receive either 10 mL of isobaric levobupivacaine (0.5% + 5 mL 0.9% saline [group 1; n = 20]) or 10 mL of isobaric levobupivacaine (0.75% + 5 mL saline 0.9% saline [group 2; n = 20]) for epidural anesthesia. An observer blinded to group division evaluated the time of onset, maximum level, and time to 2-segment regression of sensory block. RESULTS: There were no differences between the 2 groups in terms of hemodynamic parameters and time of onset of the sensory block. There were significant differences, however, between the 2 groups in the maximum level of the sensory block (group 1, T9; group 2, T8; P = 0.010) and the time to 2-segment regression of sensory block (group 1, 46.35 minutes; group 2, 62.94 minutes; P = 0.013). CONCLUSION: This study indicated that 10 mL of 0.5% levobupivacaine plus 5 mL of 0.9% saline is a suitable solution for use in epidural anesthesia because it produces a block clinically comparable to that of 10 mL of 0.75% levobupivacaine plus 5 mL of 0.9% saline for transurethral resection of prostate surgery.