Lumbar sympathetic blocks speed early and second stage induced labor in nulliparous women

Background Rapid cervical dilation reportedly accompanies lumbar sympatheti c blockade, whereas epidural analgesia is associated with slow labor. The a uthors compared the effects of initial lumbar sympathetic block with those of epidural analgesia on labor speed and delivery mode in this pilot study. Methods: At a hospital not practicing active labor management, full-term nu lliparous patients whose labors were induced randomly received initial lumb ar sympathetic block or epidural analgesia. The latter patients received 10 mi bupivacaine, 0.125%; 50 mu g fentanyl; and 100 pg epinephrine epidurall y and sham lumbar sympathetic blocks. Patients to have lumbar sympathetic b locks received 10 mi bupivacaine, 0.5%; 25 mu g fentanyl; and 50 mu g epine phrine bilaterally and epidural catheters, Subsequently, all patients recei ved epidural analgesia. Results: Cervical dilation occurred more quickly (57 is, 120 min/cm cervica l dilation; P = 0.05) during the first 2 h of analgesia in patients having lumbar sympathetic blocks (n = 17) than in patients having epidurals (n = 1 9). The second stage of labor was briefer in patients having lumbar sympath etic blocks than in those having epidurals (105 vs. 270 min; P < 0.05). Nin e patients having lumbar sympathetic block and seven having epidurals deliv ered spontaneously, whereas seven patients having lumbar sympathetic block and seven having epidurals had instrument-assisted vaginal deliveries. Cesa rean delivery for fetal bradycardia occurred in one patient having lumbar s ympathetic block. Cesarean delivery for dystocia occurred in five patients having epidurals compared with no patient having lumbar sympathetic block ( P = not significant). Visual analog pain scores differed only at GO min aft er block. Conclusions: Nulliparous parturients having induced labor and receiving ini tial lumbar sympathetic blocks had faster cervical dilation during the firs t 2 h of analgesia, shorter second-stage labors, and a trend toward a lower dystocia cesarean delivery rate than did patients having epidural analgesi a. The effects of lumbar sympathetic block on labor need to be determined i n other patient groups. These results may help define the tocodynamic effec ts of regional labor analgesia.