Abstract: Objective: To investigate the characteristics of phrenic nerve motor conduction (PNC) and motor evoked potentials of diaphragm elicited through magnetic stimulation (dMEP) in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) who experienced acute respiratory failure. Methods: PNC and dMEP were performed in 20 AECOPD patients who experienced acute respiratory failure enough to require mechanical ventilation with a Keypoint 4 electromyography device and a Magpro Compact magnetic stimulator. 20 healthy subjects were chosen as a control group. Results: The latency of PNC in AECOPD group was longer than that of the control group (P<0.01); the common logarithm of the amplitude of PNC was lower in AECOPD group than that of the control group (P<0.01); the latencies of cervical and cortical dMEP, CMCT in AECOPD group were longer than those of the control group (P<0.01 for each); the common logarithm of the amplitude of cervical dMEP in AECOPD group was decreased compared with that of the control group (P<0.01); it showed no statistical difference between two groups in the common logarithm of the amplitude of cortical dMEP (P>0.05).13 patients in AECOPD group were reexamined after weaning, the differences between two groups were the same as before weaning in latency and the common logarithm of the amplitude of PNC, the latency and the common logarithm of the amplitude of cervical dMEP and the common logarithm of the amplitude of cortical dMEP; there were no statistical differences between two groups in the latencies of cortical dMEP and CMCT (P>0.05 for each). Conclusion: There may exist dysfunction of respiratory central motor conduction, phrenic nerve and (or) diaphragm in AECOPD patients, the combined use of PNC and dMEP may help evaluate the function of phrenic nerve, diaphragm and respiratory central motor conduction in AECOPD patients.

Key words: pulmonary disease, chronic obstructiverespiratory insufficiencyphrenic nerverespiration, artificialneural conductionevoked potentials, motortranscranial magnetic stimulationelectrophysiology, 诱发电位