BACKGROUND AND OBJECTIVES: The cardiotoxic effect of racemic bupivacaine (50:50) is still the major safety-related variable for regional blocks requiring higher concentrations and volumes. Recent animal studies suggested that the manipulation of racemic bupivacaine enantiomers could contribute for a better therapeutic efficacy by decreasing its potential toxicity. This study aimed at evaluating the efficacy of 0.5% bupivacaine enantiomeric mixture (S75-R25) as compared to plain S(-100%) bupivacaine in lumbar epidural anesthesia for varicose vein surgery. METHODS: Participated in this randomized double-blind study 30 female patients aged 15 to 65 years, physical status ASA I or II scheduled for elective lower limb varicose vein surgery, who were allocated into two groups: S75-R25 Group - 20 ml (100 mg) of 0.5% (S75-R25) bupivacaine; and Levogyrous Group - 20 ml (100 mg) of 0.5% plain S(-100) bupivacaine without adjuvants. Characteristics of sensory and motor block as well as the incidence of side effects were investigated. RESULTS: Significant demographic differences and a longer surgical time were found in the S75-R25 Group. Faster spread and lower analgesic effects of the isomeric mixture were statistically significant. Motor block was significantly deeper in the S75-R25 Group. Side effects were negligible for both groups. CONCLUSIONS: Fewer side effects, good patients acceptance and the lack of post-operative transient neurological symptoms point towards the safety of both solutions in lumbar epidural anesthesia for elective varicose vein surgery. The sample, however, is still small for final conclusions.
ANESTHETICS, Local; ANESTHETICS, Local; ANESTHETIC TECHNIQUES, Regional
