超声引导下臂丛神经阻滞后对神经动作电位的影响

Effect of Ultrasound-guided Brachial Plexus Block on Nerve Action Potential

目的:研究超声引导下臂丛神经阻滞对神经动作电位的影响。方法:选取2014年2月至2016年2月我院收治的前臂闭合桡骨骨折下行切开复位内固定术患者30例为研究对象,均用0.375%左布比卡因在超声引导下肌间沟臂丛神经阻滞。检测患者注药前及注药后1 min、2 min、3 min、4 min、5 min、10 min及15 min正中神经、尺神经、桡神经、肌皮神经运动潜伏时(ML)及其肌肉复合动作电位(CMAP)的变化。结果:注药后正中神经、尺神经、桡神经、肌皮神经的CMAP均明显下降,与注药前比较,差异均有统计学意义(P<0.05),其中注药后2 min改变最大。注药后正中神经、尺神经、桡神经、肌皮神经的ML在5 min内逐渐延长,与注药前比较,差异均有统计学意义(P<0.05),而5 min、10 min及15 min的ML没有显著变化。结论:超声引导下臂丛神经阻滞对不同神经分支动作电位具有抑制作用,且阻滞起效时间具有差异性;动作电位可以作为神经阻滞后客观和量化的指标。

Objective： To study the effect of ultrasound-guided brachial plexus block on nerve action potential. Methods： A total of 30 cases of patients with radial fracture of forearm underwent the open reduction and internal fixation operation in our hospital from Feb 2014 to Feb 2016 were selected as subjects, and 0.375% levobupivacaine in the ultrasound-guided brachial plexus block was used. The motor latency （ML） and muscle compound action potential （CMAP） of median nerve, ulnar nerve, radial nerve and musculocutaneous nerve were measured before and at 1 min, 2 min, 3 min, 4 min, 5 min, 10 min and 15 min after injection. Results： The CMAP of the median nerve, ulnar nerve, radial nerve and musculocutaneous nerve significantly decreased after injection （P〈0.05）, and the change was the largest at 2 min after injection. The ML of the median nerve, ulnar nerve, radial nerve and musculocutaneous nerve gradually increased in 5 rain after injection, and the difference was statistically significant compared with that before injection （P〈0.05）, while there was no significant difference in the ML at 5 min, 10 min and 15 min （P〉0.05） . Conclusions： Ultrasound-guided brachial plexus block has inhibitory effect on the action potentials of different nerve branches, and the onset time of blocking is different. The action potential can be used as an objective and quantitative index of nerve block.