Continuous Infusion Epidural Analgesia during Labor: A Randomized, Double-blind Comparison of 0.0625% Bupivacaine / 0.0002% Fentanyl Versus 0.125% Bupivacaine

The analgesic efficacy of the continuous epidural infusion of 0.0625% bupivacaine/0.0002% fentanyl was compared with the infusion of 0.125% bupivacaine alone in a randomized, double-blind study of nulliparous women. Each patient received, in sequence1)3 ml of 0.5% bupivacaine with 1:200,000 epinephrine; 2) 6 ml of study solution 1 (bupivacaine-fentanyl group0.125% bupivacaine/ 0.0008% fentanyl; bupivacaine-only group0.25% bupivacaine alone); and 3) a continuous epidural in fusion of study solution 2 at a rate of 12.5 ml/h (bupivacaine-fentanyl group0.0625% bupivacaine/0.0002% fentanyl; bupivacaine-only group0.125% bupivacaine alone). The epidural infusion was discontinued at full cervical dilatation, but patients who lacked perineal anesthesia received one or two 5-ml boluses of study solution 3 (bupivacaine-fentanyl group0.0625% bupivacaine alone; bupivacaine-only group0.125% bupivacaine alone). During the first stage of labor, 36 of 41 (88%) women in the bupivacaine-fentanyl group, and 37 of 39 (95%) women in the bupivacaine-only group, had analgesia of excellent or good quality (P = NS). During the second stage, 22 of 37 (59%) women in the bupivacaine-fentanyl group, and 23 of 35 (66%) women in the bupivacaine-only group, rated their analgesia as excellent or good (P = NS). Women in the bupivacaine-only group were more likely to have motor block at full cervical dilatation (P