Estudo comparativo entre bupivacaína a 0,5%, mistura enantiomérica de bupivacaína (S75-R25) a 0,5% e ropivacaína a 0,75% associadas ao fentanil em anestesia peridural para cesarianas

摘要

BACKGROUND AND OBJECTIVES: Clinical trials with local anesthetic levo-enantiomers have shown higher safety due to lower cardiotoxicity. This study aimed at evaluating quality of anesthesia and maternal/fetal repercussions of 0.5% bupivacaine, enantiomeric 0.5% bupivacaine (S75-R25) and 0.75% ropivacaine, all associated to fentanyl, in epidural cesarean section anesthesia. METHODS: Participated in this study 90 full-term pregnant women, physical status ASA I, submitted to elective cesarean section under epidural anesthesia, who were divided into tree groups: group I - 23 ml racemic 0.5% bupivacaine with epinephrine; Group II -23 ml enantiomeric 0.5% bupivacaine (S75-R25) with epinephrine; Group III - 23 ml of 0.75% ropivacaine. Fentanyl (2 ml) was associated to local anesthetics in all groups. The following parameters were evaluated: onset, analgesia duration, sensory and motor block degree, time to hysterotomy and delivery, quality of muscle relaxation and anesthesia, maternal hemodynamic and respiratory changes, newborn vitality (evaluated through Apgar score and cord-blood gases analysis), and side-effects. RESULTS: There were no differences among groups, except for anesthesia quality. In groups with predominant levo-enantiomer fraction were clinically worse with the need for anesthetic complementation in three cases. Analgesia duration was longer in the ropivacaine group. CONCLUSIONS: Enantiomeric mixture 0.5% bupivacaine (S75-R25) and 0.75% ropivacaine for epidural anesthesia have provided as good conditions as racemic 0.5% bupivacaine for the surgical act. Newborn repercussions have shown that all solutions were equally safe.