The clinical effectiveness of epidural bupivacaine, bupivacaine with lidocaine, and bupivacaine with fentanyl for labor analgesia

Study Objective: To examine the efficacy of bupivacaine alone and in combination with lidocaine or fentanyl for epidural analgesia during labor. Design: Randomized, single-blind study. Setting: Labor and delivery unit at a university medical center. Patients: Forty-five primiparas requesting epidural analgesia. Interventions: Following epidural placement at L3-4 interspace, patients received either bupivacaine 0.5% (Group 1, n = 15), bupivacaine 0.25% with lidocaine 1% (Group 2, n = 15), or bupivacaine 0.5% with fentanyl 50 μg in 10 ml of saline (Group 3, n = 15). Patients in Groups 1 and 2 received 6 to 10 ml of local anesthetic depending on patient height, while patients in Group 3 received 5 ml of local anesthetic plus 50 μg of fentanyl in 10 ml of saline. All solutions contained epinephrine 1:200,000. Measurements and Main Results: Patients were assessed at regular intervals following administration of the epidural solution. Visual analog scale (VAS) scores were used to measure onset of analgesia, time to complete pain relief, duration of analgesia, and patient satisfaction with therapy. The frequency of shivering and pruritus and the extent of sensory/motor block also were evaluated. There were no intragroup differences in time to complete pain relief or patient satisfaction. However, patients in Group 3 noted the most rapid onset and longest duration of pain relief. Patients in Group 3 also experienced significantly less shivering and had the lowest degree of motor block. Two patients in Group 3 experienced mild pruritus. Conclusions: Epidurally administered fentanyl safely extended the duration of labor analgesia while reducing bupivacaine dose requirements and magnitude of motor block. In this setting, the combination of bupivacaine and lidocaine offered no clinical advantage over bupivacaine alone.