复合肌肉动作电位波幅和肌力的相关性在危重病瘫痪诊断中的价值

Relationship between Amplitude of Compound Muscle Action Potential and Muscle Strength in Critically Ill Patients with Paralysis

目的探讨复合肌肉动作电位(compound muscle action potential,CMAP)波幅和肌力的相关性在协助重症患者肢体瘫痪定位中的价值。方法采用床旁肌电图测定,对30例伴有肢体无力的重症患者进行运动神经传导测定,同时收集测定神经所支配肌肉的肌力,与CMAP波幅进行比较。结果 5例患者神经传导测定CMAP波幅和速度均正常,其中3例为明显无力,符合中枢神经系统病变的诊断。6例肢体明显无力的患者,发现有运动神经传导阻滞和传导速度减慢,CMAP波幅下降,符合脱髓鞘性周围神经病的诊断。19例表现为CMAP波幅下降,其中8例波幅明显下降(3例未引出波形),无潜伏期延长或传导速度减慢,临床查体可见8例明显无力,10例轻度无力,1例肌力正常,支持神经肌肉病变的诊断。结论将CMAP波幅和肌力结合进行分析有助于重症患者肢体瘫痪的定位,尤其在明显无力的肢体测定时价值更大。

Objective To investigate the relationship between amplitude of compound muscle action po- tential （CMAP） and muscle strength in critically ill patients with paralysis. Methods Motor nerve conduction study was performed in 30 critically ill patients with paralysis. Muscle strength was evaluated at the same time. The relationship between the amplitude of CMAP and muscle strength was analyzed. Results Amplitude of CMAP and motor conduction velocity was normal in 5 patients with paralysis, including 3 with significant mus- cle weakness. The detection results supported the diagnosis that the lesions were located in central nervous sys- tem. Six patients with significant muscle weakness had motor never conduction block, slow conduction velocity, and decreased amplitude, which supported the diagnosis of demyelinating neuropathy. Nineteen patients had decreased amplitude of CMAP, including obviously decreased amplitude in 8 patients （ no response in 3 pa- tients）. Physical examinations identified 8 patients with significant muscle weakness, 10 with mild weakness,and 1 with normal muscle strength, which confirmed the diagnosis of neuromuscular disease. Conclusion The combined assessment of muscle strength and amplitude of CMAP is helpful for the diagnosis of critically ill pa-tients with paralysis, especially for those with significant muscle weakness.