Continuous infusion epidural analgesia in labor: the effect of adding sufentanil to 0.125% bupivacaine.

The purpose of this study was to determine if the addition of sufentanil would improve the quality of analgesia obtained with 0.125% epidural bupivacaine infusions given to women in active labor. Forty healthy laboring women were randomly assigned to two equal groups. Group 1 had epidural analgesia instituted with the bolus injection of 10-15 ml 0.125% bupivacaine containing sufentanil 2 micrograms/ml, followed 30 minutes later by initiation of an epidural infusion of 0.125% bupivacaine containing sufentanil 1 microgram/ml at a rate of 10 ml/hr. Group 2 had epidural analgesia instituted with 10 or 15 ml of 0.25% bupivacaine with an epidural infusion of 0.125% bupivacaine begun 30 minutes later at a rate of 10 ml/hr. Infusion rates were altered as required to maintain an analgesic level to the tenth thoracic dermatome. Analgesia assessed by visual analog pain scores was significantly better in group 1. Significantly fewer epidural injections were required in group 1, and less motor weakness occurred in these patients. The addition of sufentanil to epidural bupivacaine infusions given in labor improves analgesia and reduces "top-up" requirements.