Augmentation of bupivacaine analgesia in labor by epidural morphine

The analgesic properties and motor effect of epidural 0.257c bupivacaine (8 mL) were compared with those of epidural morphine (2 mg in 10 mL saline) followed by 8 mL of 0.25% bupivacaine. The study was performed on two groups of parturients (30 in each group) in active labor. Pain relief in the morphine-bupivacaine group lasted for a mean of 131.1 minutes (SD ± 49.8) as opposed to the plain bupivacaine group -57 minutes (SD ± 15.28). Satisfaction from analgesia in the morphine-bupivacaine group was higher as well. Motor involvement was not seen in either group. Perineal pain relief in the postpartum period lasted for a mean of 16 hours and 40 minutes in the morphine-bupivacaine group. It was concluded that the concomitant use of epidural morphine augmented the analgesic effect of 0.25% bupivacaine without motor effect.