Bupivacaína levógira a 0,5% pura versus mistura enantiomérica de bupivacaína (S75-R25) a 0,5% em anestesia peridural para cirurgia de varizes

摘要

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.