Capogna G, Celleno D, Lyons G, Columb M, Fusco P
Department of Anaesthesiology, Fatebenefratelli General Hospital, Rome, Italy.
Br J Anaesth. 1998 Jan;80(1):11-3. doi: 10.1093/bja/80.1.11.
We have used the technique of double-blind sequential allocation to quantify the minimum local analgesic concentration (MLAC) of extradural bupivacaine for women in early (median cervical dilatation 2 cm) and late (median cervical dilatation 5 cm) labour. The first bolus was 20 ml of the bupivacaine test solution. The concentration was determined by the response of the previous woman to a higher or lower concentration of bupivacaine according to up and down sequential allocation. Efficacy was assessed using a 100-mm visual analogue pain score (VAPS). The test solution had to achieve a VAPS of 10 mm or less to be judged effective. In early labour, the MLAC of bupivacaine was 0.048% w/v (95% confidence intervals (CI) 0.037-0.058% w/v), and 0.140% w/v (95% CI 0.132-0.150% w/v) in the late group. The MLAC of bupivacaine in late labour was greater by a factor of 2.9 (95% CI 2.7-3.2) compared with the MLAC in early labour (P < 0.0001, 95% CI difference 0.08-0.11). We conclude that advancing labour requires an increased concentration of extradural bupivacaine for pain relief.
我们采用双盲序贯分配技术，对硬膜外布比卡因用于早期（宫颈扩张中位数为2厘米）和晚期（宫颈扩张中位数为5厘米）分娩女性的最低局部镇痛浓度（MLAC）进行了量化。首次推注为20毫升布比卡因测试溶液。根据上下序贯分配，浓度由前一位女性对更高或更低浓度布比卡因的反应来确定。使用100毫米视觉模拟疼痛评分（VAPS）评估疗效。测试溶液必须达到10毫米或更低的VAPS才能被判定为有效。在分娩早期，布比卡因的MLAC为0.048% w/v（95%置信区间（CI）0.037 - 0.058% w/v），晚期组为0.140% w/v（95% CI 0.132 - 0.150% w/v）。与分娩早期相比，分娩晚期布比卡因的MLAC高2.9倍（95% CI 2.7 - 3.2）（P < 0.0001，95% CI差值0.08 - 0.11）。我们得出结论，随着产程进展，需要更高浓度的硬膜外布比卡因来缓解疼痛。
