Background and objective: Epidural analgesia with bupivacaine plus either sufentanil or fentanyl is widely used during labour, but it is not clear which opioid is to be preferred. The study compared these opioids at equianalgesic doses in terms of analgesia, onset time and side-effects.

Methods: Ninety females in active labour were entered into the randomized, double-blind trial. A test dose of bupivacaine was given into the epidural space. Parturients in Group S received sufentanil 8 mL as a bolus dose, followed by an infusion at a rate of 5 mL h−1 of a mixture containing sufentanil 1 µg mL−1 and bupivacaine 1 mg mL−1. Patients in Group F received fentanyl 8 mL as a bolus, followed by an infusion at 5 mL h−1 of a solution containing fentanyl 3.5 µg mL−1 and bupivacaine 1 mg mL−1. Additional boluses of 5 mL were of the relevant solution were given if necessary.

Results: In a ratio of 1.0 : 3.5 (sufentanil 1 µg versus fentanyl 3.5 µg), both groups reported the same analgesia with the same onset time. The onset time to obtain 50% of the initial visual analogue score was 10 and 11 min for Groups S and F, respectively. Mean visual analogue scores in Groups S and F respectively declined from 77 and 82 before epidural blockade, to 29 and 27 during the first stage of labour, and to 69 and 59 respectively during the second stage. Overall satisfaction among parturients was high (98 and 96%), particularly during the first stage (98 and 98%), and also to a large degree during the second stage of labour (74 and 79%). Furthermore, only a few extra bolus doses were required (mean 0.9 and 1.2, Groups S and F, respectively). All the females could stand on their own, and almost all (81% Group S; 79% Group F) could walk 20 m without help. There were no serious adverse effects. Moderate side-effects occurred equally often with the possible exception of less nausea and vomiting in the fentanyl group.

Conclusions: Epidural analgesia for ambulatory parturients with bupivacaine plus either sufentanil or fentanyl (ratio 1.0 : 3.5) provides good analgesia with a low frequency of modest side-effects. No clinical differences were found between the opioids.