Comparison of Epidural Anesthesia with 0.5% Levobupivacaine and 0.5% Ropivacaine for Cesarean Section

Background: Ropivacaine and levobupivacaine, both single S-enantiomers, show less toxicity on the central nervous and cardiovascular system than racemic bupivacaine. Earlier studies have shown that levobupivacaine and bupivacaine are almost equipotent while ropivaciane was 60% less potent than bupivacaine. The aim of this prospective, double blinded study was to compare the clinical efficacy and safety of epidural anesthesia produced by 0.5% levobupivacaine and 0.5% ropivacaine for a cesarean section. Methods: Sixty-two parturients undergoing an elective cesarean section were randomized to receive either epidural levobupivacaine 0.5% 20 ml (n = 31) or epidural ropivacaine 0.5% 20 ml (n = 31). Surgery was commenced when the sensory block had reached the dermatome level, T6. The onset, duration, quality of the sensory and motor block and abdominal muscle relaxation were evaluated. The blood pressure and heart rate of the mother and neonatal outcome, as assessed by the Apgar score and umbilical pH, were also recorded. Results: There was no difference in the onset time, the segmental spread of sensory block and analgesic supplement between the two groups. However, levobupivacaine produced a longer duration of sensory block than ropivacaine (levobupivacaine 224.1 ± 66.6 min, ropivacaine 176.5 ± 32.8 min, P ＜ 0.05). The onset time (except Bromage scale 2), intensity and duration of the motor block and muscle relaxation were similar in both groups. There was no difference in the maternal and neonatal outcomes between the two groups. Conclusions: 0.5% levobupivacaine and 0.5% ropivacaine produced equivalent efficacy and safety in epidural anesthesia for a cesarean section, but levobupivacaine resulted in a longer duration of sensory block. (Korean J Anesthesiol 2007; 52: 284~90)