Similowski T, Mehiri S, Duguet A, Attali V, Straus C, Derenne J P
Service de Pneumologie et Réanimation and Laboratoire de Physiopathologie Respiratoire, Groupe Hospitalier Pitié-Salpêtrière,Paris, France.
J Appl Physiol (1985). 1997 Apr;82(4):1190-9. doi: 10.1152/jappl.1997.82.4.1190.
Cervical magnetic stimulation (CMS), a nonvolitional test of diaphragm function, is an easy means for measuring the latency of the diaphragm motor response to phrenic nerve stimulation, namely, phrenic nerve conduction time (PNCT). In this application, CMS has some practical advantages over electrical stimulation of the phrenic nerve in the neck (ES). Although normal ES-PNCTs have been consistently reported between 7 and 8 ms, data are less homogeneous for CMS-PNCTs, with some reports suggesting lower values. This study systematically compares ES- and CMS-PNCTs for the same subjects. Surface recordings of diaphragmatic electromyographic activity were obtained for seven healthy volunteers during ES and CMS of varying intensities. On average, ES-PNCTs amounted to 6.41 +/- 0.84 ms and were little influenced by stimulation intensity. With CMS, PNCTs were significantly lower (average difference 1.05 ms), showing a marked increase as CMS intensity lessened. ES and CMS values became comparable for a CMS intensity 65% of the maximal possible intensity of 2.5 Tesla. These findings may be the result of phrenic nerve depolarization occurring more distally than expected with CMS, which may have clinical implications regarding the diagnosis and follow-up of phrenic nerve lesions.
颈部磁刺激（CMS）是一种检测膈肌功能的非自主性测试方法，是测量膈肌对膈神经刺激的运动反应潜伏期（即膈神经传导时间，PNCT）的简便手段。在该应用中，与颈部膈神经电刺激（ES）相比，CMS具有一些实际优势。尽管正常的ES-PNCT一直报告在7至8毫秒之间，但CMS-PNCT的数据不太一致，一些报告显示其值较低。本研究系统地比较了同一受试者的ES-PNCT和CMS-PNCT。在不同强度的ES和CMS过程中，对7名健康志愿者进行了膈肌肌电图活动的表面记录。平均而言，ES-PNCT为6.41±0.84毫秒，受刺激强度影响较小。对于CMS，PNCT显著更低（平均差异1.05毫秒），随着CMS强度降低呈现明显增加。当CMS强度为2.5特斯拉最大可能强度的65%时，ES和CMS的值变得相当。这些发现可能是由于CMS时膈神经去极化发生的位置比预期更远，这可能对膈神经病变的诊断和随访具有临床意义。
