Beilin Y, Arnold I, Telfeyan C, Bernstein H H, Hossain S
Department of Anesthesiology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029-6574, USA.
Reg Anesth Pain Med. 2000 Nov-Dec;25(6):596-9. doi: 10.1053/rapm.2000.9535.
Identification of the epidural space is often performed using the loss-of-resistance technique (LOR), commonly with air or saline. The effect of air or saline on the quality of labor epidural analgesia has not been adequately studied.
Women who requested labor epidural analgesia were randomly assigned to 1 of 2 groups depending on the syringe contents used for the LOR technique and injected into the epidural space. In the air group (n = 80) the anesthesiologist used 2 mL of air, and in the saline group (n = 80) the anesthesiologist used 2 mL of 0.9% saline. After LOR was obtained, a multiorifice epidural catheter was threaded 5 cm into the epidural space and 13 mL of bupivacaine 0.25% was administered in divided doses. The success of the epidural block was determined by asking the patient if she required additional medication 15 minutes later. The occurrence of paresthesias and intravascular or subarachnoid catheters was noted.
In the air group, 36% of patients requested additional pain medication, and in the saline group 19% requested additional medication (P =.022). We were not able to find a statistically significant difference between groups in the incidence of paresthesias (42% air v 51% saline), intravascular catheters (5% air v 8% saline), or subarachnoid catheters (0 in both groups).
Using 0.9% saline for the LOR technique is associated with better analgesia as compared with air for labor analgesia, and this advantage should be considered when selecting the syringe contents for the LOR technique.
硬膜外腔的识别通常采用阻力消失技术（LOR），常用空气或生理盐水。空气或生理盐水对分娩硬膜外镇痛质量的影响尚未得到充分研究。
根据用于LOR技术并注入硬膜外腔的注射器内容物，将要求进行分娩硬膜外镇痛的女性随机分为两组。在空气组（n = 80）中，麻醉医生使用2 mL空气，在生理盐水组（n = 80）中，麻醉医生使用2 mL 0.9%生理盐水。获得阻力消失后，将多侧孔硬膜外导管置入硬膜外腔5 cm，并分次注入13 mL 0.25%布比卡因。15分钟后询问患者是否需要额外用药，以确定硬膜外阻滞是否成功。记录感觉异常、血管内或蛛网膜下腔置管的发生情况。
空气组中，36%的患者需要额外的止痛药物，生理盐水组中19%的患者需要额外用药（P = 0.022）。我们未能发现两组在感觉异常发生率（空气组42%对生理盐水组51%）、血管内置管率（空气组5%对生理盐水组8%）或蛛网膜下腔置管率（两组均为0）方面存在统计学显著差异。
与空气相比，使用0.9%生理盐水进行LOR技术用于分娩镇痛时镇痛效果更好，在选择LOR技术的注射器内容物时应考虑这一优势。
