Keywords Chronic obstructive pulmonary disease;Muscular fatigue of diaphragm;Diaphragm electromyogram;Phrenic nerve conduction time;Action potential;Noninvasive positive pressure ventilation;

• 慢性阻塞性肺疾病;膈肌疲劳;膈神经传导时间;动作电位;无创正压通气;