Augmentation of bupivacaine analgesia in labor by epidural morphine

The analgesic properties and motor effect of epidural 0.25% 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.