Continuous mini-infusion of bupivacaine into the epidural space during labor. Part III: A clinical study of 225 patients.
Obstetric analgesia was accomplished by segmental continuous blockade in 225 women. The technique involved automatic pump infusion of 0.25 per cent bupivacaine solution into the epidural space at a rate of 5 ml per hour after initial doses of 2 and 5 ml bupivacaine. If the analgesia was insufficient one or two single injections of 5 ml of bupivacaine were added. Statistical evaluation of the results could be carried out for 218 women, 158 of whom were nulliparae and 60 multiparae. Fully satisfactory analgesia was achieved in 96 per cent of the nulliparae and 88 per cent of the multiparae in the first stage of labor. In the second stage of labor 46 per cent of the mothers were given pudendal blockade to maintain statisfactory analgesia. The positioning of the patient in the first stage of labor from supine to semirecumbent was of importance to spread the analgesic agent caudally, to the sacral nerve roots, and to control the pain due to stretching of the vagina and perineum. In the total material 17 per cent of the neonates were delivered by vacuum extraction. When the infusion into the epidural space was started in early labor, the incidence of vacuum extraction was 9 per cent, as compared with 38 per cent when it was started at 6 cm cervical dilatation or later (p less than 0.01). 9.8 per cent of the neonates were delivered by cesarean section. Fetal head malposition occurred in 8.7 per cent. A drop in blood pressure was noted in 7 per cent of the women. The condition of the newborn was unaffected by the analgesia. The mini-infusion system minimized the risk for infection. The danger in case of accidental intravascular injection was reduced, due to slowly administered bupivacaine. At the maternity department this technique has created a positive attitude towards epidural blockade, as midwives and doctors have found it safe and easy.