Effect of diluting fentanyl on epidural bupivacaine during labor analgesia.

In a randomized prospective study carried out on 60 laboring primiparous parturients, fentanyl 80 μg, either in 2 ml or in 8 ml, was added to 12 ml of 0.25% bupivacaine administered epidurally for pain relief. The aims of this protocol were to evaluate the effect of varying the volume of fentanyl added to epidural bupivacaine on the quality and duration of labor analgesia. There was no significant difference in either the duration or quality of analgesia between the two groups. The incidence of pruritus was higher in the fentanyl-diluted group (43% versus 23%). No clinical advantage was found in this study, therefore, when fentanyl 80 μg was added to 0.25% bupivacaine.