RESUMO
OBJECTIVE: To compare the analgesic efficacy of epidural administration of 0.2% ropivacaine alone to that of 0.1% ropivacaine plus 0.0002% fentanyl during childbirth. PATIENTS AND METHODS: We performed a prospective, randomized single-blind study of 84 women in labor (aged 16 to 40 y, ASA I-II, weight over 110 kg, height over 150 cm, gestational age 37 to 42 weeks). The women were randomly assigned to two groups: group I consisted of 42 patients who received an initial bolus of 10 ml of ropivacaine 0.2% followed by continuous perfusion of ropivacaine 0.2% at a rate of 6 to 10 ml/h; group II was composed of 42 women who received an initial bolus of ropivacaine 0.2% with 50 micrograms of fentanyl followed by continuous infusion of ropivacaine 0.1% and fentanyl 2 micrograms/ml at a rate of 6 to 10 ml/h. Data recorded were parity and type of delivery, blood pressure, heart rate (HR), time to onset of pain relief, motor blockade on a modified Bromage scale, pain on a visual analog scale (VAS) and fetal HR, Apgar score and arterial and venous pH of umbilical blood. RESULTS: We found no significant differences in demographic or hemodynamic data in mothers or fetuses, in type of delivery or motor block, although the latter tended to be slightly lower in group II. In group II, the total anesthetic dose used was significantly lower (p = 0.003); time until onset of pain relief was significantly shorter (p = 0.044); and VAS scores were significantly lower at 15 min (p = 0.005), 30 min (p = 0.029), 60 min (p = 0.017) and 90 min (p = 0.002). The number of top-up boluses needed for deliveries involving instruments was significantly greater in group II (p = 0.37). CONCLUSION: The protocol of ropivacaine 0.1% with 2 micrograms/ml of fentanyl provides satisfactory analgesia throughout labor, allowing lower doses of local anesthetic to be used, with shorter onset of pain relief and reduced motor blockade; however the analgesia provided is insufficient for deliveries assisted by instruments.