Atanassoff P G, Weiss B M, Brull S J, Horst A, Külling D, Stein R, Theiler I
Department of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Anesth Analg. 1996 Feb;82(2):317-20. doi: 10.1097/00000539-199602000-00018.
The purpose of this investigation was to establish an objective (quantitative) method for determining onset time of motor block induced by different local anesthetics. Twenty-four consenting patients undergoing transurethral surgery during spinal anesthesia were randomized to receive direct obturator nerve block with 10 mL of plain bupivacaine 0.5% (n = 12) or 10 mL of plain etidocaine 1% (n = 12). Another 14 patients (control group) received obturator nerve "block" with saline. After identification of the obturator nerve, patients underwent testing of nerve conduction by recording compound motor action potentials (CMAPs) of thigh adductor muscles in response to stimulation provided by a nerve stimulator at 0.2 to 0.5-mA currents. Testing ended when CMAP amplitudes had returned to their baseline values (control group) or when motor blockade was 90% complete (local anesthetic groups). In all 38 patients, the amplitude of the thigh CMAPs decreased immediately after injection of saline or local anesthetic. While CMAP amplitudes in the control group returned to their initial (baseline) values after 3-6 min, the patients receiving etidocaine or bupivacaine achieved > or = 90% motor blockade after 6 and 13 min, respectively. In the present report, the time to > or = 90% block was significantly faster in patients given etidocaine compared with those given bupivacaine. We conclude that electromyographic recording of CMAPs can be used to compare the ability of different local anesthetics to induce motor block.
本研究的目的是建立一种客观（定量）方法，以确定不同局部麻醉药引起运动阻滞的起效时间。24例在脊髓麻醉下行经尿道手术且表示同意的患者被随机分为两组，一组接受10毫升0.5%的布比卡因原液直接闭孔神经阻滞（n = 12），另一组接受10毫升1%的依替卡因原液直接闭孔神经阻滞（n = 12）。另外14例患者（对照组）接受用生理盐水进行的闭孔神经“阻滞”。在识别闭孔神经后，患者通过记录大腿内收肌的复合运动动作电位（CMAPs）来接受神经传导测试，该电位是对神经刺激器以0.2至0.5毫安电流刺激的反应。当CMAP振幅恢复到基线值（对照组）或运动阻滞达到90%完成时（局部麻醉药组），测试结束。在所有38例患者中，注射生理盐水或局部麻醉药后，大腿CMAP振幅立即下降。对照组的CMAP振幅在3 - 6分钟后恢复到初始（基线）值，而接受依替卡因或布比卡因的患者分别在6分钟和13分钟后达到≥90%的运动阻滞。在本报告中，接受依替卡因的患者达到≥90%阻滞的时间比接受布比卡因的患者明显更快。我们得出结论，CMAP的肌电图记录可用于比较不同局部麻醉药诱导运动阻滞的能力。
