Abstracts and Programme: EUROANAESTHESIA 2011: The European Anaesthesiology Congress: Best Abstracts - Runner-up Session 1
Background and Goal of Study: PIEB resulted in reduced total local anesthetic dose and fewer additional boluses when compared to CEI1. We evaluated whether PIEB may decrease the incidence of motor block (MB) at full cervical dilatation and of instrumental delivery when compared with CEI.
Materials and Methods: Nulliparous term women with spontaneous labor and cervical dilation < 4 cm, were admitted to this study. Epidural analgesia was initiated and maintained with levobupivacaine (L) 0.0625% + sufentanil 0.5 μg/mL. After 20 mL loading dose (LD), patients were randomized to receive PIEB (10 mL every hour starting 60 min after the LD) or CEI (10 mL/h, starting immediately after the LD). Breakthrough pain was treated by PCEA with L 0.125%. MB was assessed by the Bromage-Breen2 scale (end point = occurrence of any motor block in either lower limb). Total L dose and hourly VAPS were noted. A sample of 70 subjects in each group guaranteed a power of at least 80% for a χ2 test of association between both technique and MB, and technique and instrumental delivery (significance level 5%). Statistics were performed by Fisher exact, χ2, Wilcoxon, Mann-Whitney tests and logistic regression where appropriate.
Results: We studied 145 subjects (PIEB =75; CEI =70). No differences in labor analgesia and duration of labor were observed. MB was reported in 37% in the CEI group and in 2.7% in the PIEB group (P< 0.001), and it was more frequent at full cervical dilatation in the CEI group (P< 0.001). The OR for MB was 21.17 (95%CI 4.9-129.3). MB occurred earlier in patients who received CEI (P< 0.001) with a HR of 7.83 (95%CI 1.99-30.81 P=0.0032). The incidence of instrumental delivery was 20% for the CEI group and 6.7% for the PIEB group (P=0.03). The longer the labor, the more the risk of instrumental delivery increased (P< 0.001, OR: 4.85, CI95%: 1.97-11.85). MB at full cervical dilatation significantly increased the risk of instrumental delivery (P=0.0019, OR: 230.26, CI 95%: 7.48-888.72). There was no difference in the cesarean section rate (21% CEI vs 17% PIEB). Total L dose was 36.9 mg (30.5-44.2) in the CEI group and 31.2 mg (25.0-37.5) in the PIEB group (P< 0.001).
Conclusions: PIEB resulted in less MB during labor and at full cervical dilatation and was also associated with a lower incidence of operative delivery when compared with CEI while providing equivalent labor analgesia.
1. Wong CA et al. Anesth Analg 2006.
2. Breen TW et al. Anesth Analg