Siersted H C, Walker C M, O'Shaughnessy A D, Willan A R, Wiecek E M, Sears M R
Dept of Medicine, McMaster University, Hamilton, Ontario, Canada.
Eur Respir J. 2000 Jan;15(1):181-4. doi: 10.1183/09031936.00.15118100.
In the European Community Respiratory Health Study (ECRHS), airway responsiveness to methacholine was determined using the Mefar dosimeter protocol. Elsewhere, the 2-min tidal breathing method has become the preferred standardized method. The relationship between measurements of responsiveness by these two methods is not well established. This study measured airway responsiveness to methacholine by dosimeter and tidal breathing methods in 47 healthy asthmatic subjects aged 20-44 yrs. Tests were performed within 1 week and in random order. Baseline forced expiratory volume in one second (FEV1) varied by <10% between tests in 42/47 subjects. There was a close association between responsiveness determined by the two methods. A provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) value of < or =8.0 mg x mL(-1) (tidal method) used to categorize airway hyperresponsiveness agreed most closely with a provocative dose of methacholine causing a 20% fall in FEV1 (PD20) value of < or =0.5 mg (dosimeter method) (kappa statistic 0.78). Each doubling or halving of PC20 to define a level of hyperresponsiveness agreed closely with a doubling or halving of PD20. Assessment of airway responsiveness as provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second by the Mefar dosimeter protocol gave a close and predictable relationship with provocative concentration of methacholine causing a 20% fall in expiratory volume in one second assessed using the tidal breathing method. Airway hyperresponsiveness as determined by the accepted criterion of provocative concentration of methacholine causing a 20% fall in expiratory volume in one second < or =8 mg x mL(-1) was best correlated with provocative dose of methacholine causing a 20% fall in forced expiratory volume in one second <0.5 mg by Mefar dosimeter.
在欧洲共同体呼吸健康研究（ECRHS）中，使用Mefar剂量仪方案测定对乙酰甲胆碱的气道反应性。在其他地方，2分钟潮气呼吸法已成为首选的标准化方法。这两种方法测定的反应性之间的关系尚未完全明确。本研究采用剂量仪法和潮气呼吸法，对47名年龄在20 - 44岁的健康哮喘患者进行了对乙酰甲胆碱的气道反应性测定。测试在1周内进行，且随机安排顺序。42/47名受试者两次测试之间的基线一秒用力呼气量（FEV1）变化小于10%。两种方法测定的反应性之间存在密切关联。用于分类气道高反应性的、使FEV1下降20%时的乙酰甲胆碱激发浓度（PC20）值≤8.0 mg·mL⁻¹（潮气法），与使FEV1下降20%时的乙酰甲胆碱激发剂量（PD20）值≤0.5 mg（剂量仪法）最为密切相关（kappa统计量为0.78）。将PC20翻倍或减半来定义高反应性水平，与PD20的翻倍或减半密切一致。按照Mefar剂量仪方案，将气道反应性评估为使一秒用力呼气量下降20%时的乙酰甲胆碱激发剂量，与采用潮气呼吸法评估的使一秒呼气量下降20%时的乙酰甲胆碱激发浓度之间存在密切且可预测的关系。按照公认标准，即使一秒呼气量下降20%时的乙酰甲胆碱激发浓度≤8 mg·mL⁻¹所确定的气道高反应性，与Mefar剂量仪测定的使一秒用力呼气量下降20%时的乙酰甲胆碱激发剂量<0.5 mg相关性最佳。
