Lai Y Y, Chang C L, Yeh F C
Department of Anesthesiology, College of Medicine and Hospital, National Cheng Kung University, Tainan City, Taiwan.
Ma Zui Xue Za Zhi. 1993 Mar;31(1):31-4.
Despite vast clinical experience and success with intravenous regional anaesthesia (IVRA), the site and mode of action of the local anesthetic agents remains controversial. Many investigations have been published, but conclusions are variable. The principal site of action of lidocaine in IVRA was studied using 15 ASA I-II patients receiving surgical operation on the hands and forearms. A 22 gauge plastic cannula was inserted into the median cubital vein at the elbow. A double cuff tourniquet was secured on the upper arm, as described by Bier and modified by Homes. Another single tourniquet was then applied on the forearm as near the plastic catheter as possible. Two different concentrations of lidocaine (0.5% and 2%) in a total dose of 3 mg kg-1 was slowly injected into the vein via the catheter after the limb was exsanguinated and the tourniquets were inflated. The results showed that 0.5% lidocaine produced analgesia only on the intercuff area; there was no analgesic response noted on the forearm distal to the third tourniquet after a 15 minutes observation. However patients who received 2% lidocaine experienced in analgesia rapidly on the intercuff area and also slowly on the forearm and hand. The anesthesia developed from the fingertips upward. Based on this evidence, we concluded that the principal site of action of lidocaine in IVRA depends on concentration. The lower concentration acts on the sensory nerve endings and the small nerves. Whereas, the higher concentration acts on both nerve trunks and nerve endings.
尽管静脉区域麻醉（IVRA）有着丰富的临床经验且成效显著，但局部麻醉药的作用部位和作用方式仍存在争议。已经发表了许多研究，但结论各不相同。使用15例接受手部和前臂手术的ASA I-II级患者，研究了利多卡因在IVRA中的主要作用部位。在肘部的肘正中静脉插入一根22号塑料套管。按照比尔（Bier）描述并经霍姆斯（Homes）改良的方法，在上臂固定一个双袖带止血带。然后在靠近塑料导管的前臂尽可能近的位置再应用一个单止血带。在肢体放血且止血带充气后，通过导管将两种不同浓度（0.5%和2%）、总剂量为3mg/kg的利多卡因缓慢注入静脉。结果显示，0.5%的利多卡因仅在袖带间区域产生镇痛作用；观察15分钟后，在第三个止血带远端的前臂未观察到镇痛反应。然而，接受2%利多卡因的患者在袖带间区域迅速出现镇痛作用，在前臂和手部也缓慢出现镇痛作用。麻醉从指尖向上发展。基于这些证据，我们得出结论，利多卡因在IVRA中的主要作用部位取决于浓度。较低浓度作用于感觉神经末梢和小神经。而较高浓度则作用于神经干和神经末梢。
