Epidural analgesia for labour using a continuous infusion of bupivacaine and alfentanil

Seventy women who requested epidural pain relief in labour received a continuous epidural infusion at 8 ml h-1, which contained either 0.25% bupivacaine (n = 29), or a mixture of 0.125% bupivacaine and 0.005% alfentanil (n = 31), assigned randomly. Increments of 4 ml 0.25% bupivacaine were given on demand to prevent residual pain from uterine contractions. The two groups were compared for motor block of the lower limbs, number of increments required, type of delivery and neonatal Apgar scores. The group of women receiving the mixture of bupivacaine and alfentanil required between them seven increments; the group receiving bupivacaine alone required 15. One of the women receiving the mixture and eight of the women receiving bupivacaine alone had almost complete motor block. There were no differences in the mode of delivery or in the neonatal Apgar scores.