Epidural block for cesarean section: a comparative study between 0.5% racemic Bupivacaine (S50-R50) and 0.5% enantiomeric excess Bupivacaine (S75-R25) associated with Sufentanil.

BACKGROUND AND OBJECTIVES

Epidural 0.5% racemic bupivacaine associated with opioids is a technique used in cesarean sections; however, its toxicity has been questioned. 50% Enantiomeric excess bupivacaine has lower cardio- and neurotoxicity. The efficacy of epidural 0.5% racemic bupivacaine and 0.5% enantiomeric excess bupivacaine associated with sufentanil in parturients undergoing cesarean sections was evaluated.

METHODS

Fifty gravida at term, undergoing elective cesarean section under epidural block, were divided in two groups according to the local anesthetic used: Group I - 0.5% racemic bupivacaine with vasoconstrictor; and Group II - 0.5% enantiomeric excess bupivacaine (S75-R25) with vasoconstrictor. In both groups, the local anesthetic (100 mg) was associated with sufentanil (20 microg), and a total of 24 mL of the solution was used. The following parameters were evaluated: latency of the sensitive blockade; maximal level of the sensitive blockade; degree for motor blockade; time of motor blockade regression; duration of analgesia; maternal side effects; and neonatal repercussions.

RESULTS

Latency, maximal level of sensitive blockade, degree of motor blockade, and duration of analgesia were similar in both groups; the mean time for regression of the motor blockade was significantly smaller in Group II. The incidence of side effects was similar in both groups. Maternal cardiocirculatory changes and neonatal repercussions were not observed.

CONCLUSIONS

Epidural racemic bupivacaine and 50% enantiomeric excess bupivacaine provided adequate anesthesia for cesarean sections. 50% Enantiomeric excess bupivacaine is a promising alternative for this procedure, since it has faster regression of the motor blockade, which is desirable in obstetric patients.