Objective: To explore the application value of surface respiratory muscle electromyography and its ratio to tidal volume in the assessment of airway hyperresponsiveness in bronchial asthma patients. Methods: A case-control study was conducted to retrospectively analyze the data of 29 asthma patients who visited the outpatient department of respiratory medicine of the First Affiliated Hospital of Guangzhou Medical University from October 2015 to May 2017 and 27 non-asthmatic subjects who were recruited as the control group.Changes in surface respiratory muscle electromyography (parasternal, EMGpara, diaphragmatic, EMGdi), and its ratio to tidal volume (EMGpara/VT, EMGdi/VT) before and after the histamine challenge test were compared between the asthma group and the control group; and their receiver operating characteristic (ROC) curves were plotted. Results: The average age of 29 patients in the asthma group was (50±13) years (male: female=14∶15), while that of 27 subjects in the control group was (35±13) years (male: female=11∶16). After the histamine challenge test, EMGdi, EMGdi/VT, EMGpara, and EMGpara/VT in the 29 asthma patients were 16.5 (11.4, 19.7)μV, 1.8 (1.4, 2.3) μV·kg/ml, 11.9 (10.0, 15.0) μV, and 1.3 (1.0, 1.7) μV·kg/ml, respectively, which were significantly higher than those at baseline [12.0 (8.5, 6.0) μV, 0.9 (0.7, 1.3) μV·kg/ml, 9.4 (7.2, 12.8) μV, and 0.8 (0.7, 1.1) μV·kg/ml, all P<0.001]. Changes of EMGdi, EMGdi/VT, EMGpara, and EMGpara/VT(ΔEMGdi, ΔEMGdi/VT, ΔEMGpara, and ΔEMGpara/VT) in the asthma group before and after the provocation test were 37.2% (16.2%, 60.5%), 77.1% (40.3%, 145.9%), 28.9% (15.4%, 50.9%), and 62.2% (36.6%, 109.1%)%, respectively, which were significantly greater than those in the control group [0.9% (-17.2%, 9.0%), 0.7% (-13.3%, 20.1%), 3.9% (-11.0%, 10.0%), and-2.0% (-12.7%, 21.4%), all P<0.001]. The sensitivities of ΔEMGdi, ΔEMGdi/VT, ΔEMGpara, and ΔEMGpara/VT for diagnosing airway hyperresponsiveness were 79.3%, 86.2%, 75.9%, and 79.3%, respectively, while the specificities were 85.2%, 96.3%, 92.6%, and 92.6%, respectively. The areas under ROC curves (AUC) for ΔEMGdi, ΔEMGdi/VT, ΔEMGpara, and ΔEMGpara/VT were 0.842 (95%CI: 0.720-0.926), 0.917 (95%CI: 0.812-0.974), 0.843 (95%CI: 0.721-0.926), and 0.916 (95%CI: 0.810-0.973) respectively, with no statistically significant differences among these AUC values (all P>0.05). Conclusion: Surface respiratory muscle (parasternal, diaphragmatic) EMG and its ratio to tidal volume can accurately reflect the changes of airway resistance during bronchial provocation test, and differentiate asthma patients from non-asthmatic subjects, which therefore could be an alternative for the asthma diagnosis.
目的： 探讨体表呼吸肌肌电及其与潮气量比值评估支气管哮喘（简称哮喘）患者气道高反应性的应用价值。 方法： 采用病例对照研究，回顾性分析2015年10月至2017年5月就诊于广州医科大学附属第一医院呼吸内科门诊的29例哮喘患者资料，以27名非哮喘受试者为对照组。比较哮喘组和对照组支气管激发试验前后体表呼吸肌肌电［胸骨旁肌肌电（EMGpara）和膈肌肌电（EMGdi）］及其与潮气量（VT）比值（EMGpara/VT和EMGdi/VT）的变化，绘制各指标激发试验前后变化率即ΔEMGdi、ΔEMGdi/VT、ΔEMGpara和ΔEMGpara/VT诊断哮喘气道高反应性的受试者工作特征（ROC）曲线，评价其诊断效能。 结果： 哮喘组年龄为（50±13）岁，其中男14例，女15例；对照组年龄为（35±13）岁，其中男11名，女16名。激发试验后，哮喘组EMGdi、EMGdi/VT、EMGpara和EMGpara/VT［M（Q1，Q3）］分别为16.5（11.4，19.7）μV、1.8（1.4，2.3）μV·kg/ml、11.9（10.0，15.0）μV和1.3（1.0，1.7）μV·kg/ml，均高于激发试验前［分别为12.0（8.5，6.0）μV、0.9（0.7，1.3）μV·kg/ml、9.4（7.2，12.8）μV和0.8（0.7，1.1）μV·kg/ml，均P<0.001］。哮喘组激发试验前后ΔEMGdi、ΔEMGdi/VT、ΔEMGpara和ΔEMGpara/VT分别为37.2%（16.2%，60.5%）、77.1%（40.3%，145.9%）、28.9%（15.4%，50.9%）和62.2%（36.6%，109.1%），均高于对照组［分别为0.9%（-17.2%，9.0%）、0.7%（-13.3%，20.1%）、3.9%（-11.0%，10.0%）和-2.0%（-12.7%，21.4%），均P<0.001］。ΔEMGdi、ΔEMGdi/VT、ΔEMGpara和ΔEMGpara/VT诊断气道高反应性的灵敏度分别为79.3%、86.2%、75.9%和79.3%，特异度分别为85.2%、96.3%、92.6%和92.6%，ROC曲线下面积（AUC）分别为0.842（95%CI：0.720~0.926）、0.917（95%CI：0.812~0.974）、0.843（95%CI：0.721~0.926）和0.916（95%CI：0.810~0.973），AUC之间两两比较差异均无统计学意义（均P>0.05）。 结论： EMGdi、EMGpara、EMGdi/VT和EMGpara/VT均能有效反映支气管激发试验前后气道阻力的变化，区别非哮喘受试者与哮喘患者，可作为一种替代的哮喘辅助诊断手段。.