Asthma induced by cold air and its relation to nonspecific bronchial responsiveness to methacholine.
Asthma induced by cold air and its relation to nonspecific bronchial responsiveness to methacholine.
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冷空气诱发的哮喘及其与乙酰甲胆碱非特异性支气管反应的关系。
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
F. Hargreave
中科院分区：
文献类型：
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作者：
P. O'Byrne;G. Ryan;M. Morris;D. McCormack;N. Jones;J. Morse;F. Hargreave
我们比较了24名当前或既往哮喘患者和2名非哮喘患者在-18 ℃和0%湿度下对冷干燥空气等二氧化碳过度通气的支气管反应性与对吸入乙酰甲胆碱的支气管反应性。在连续4天中以随机顺序对每种药剂进行两次吸入试验。对冷空气的反应表示为使FEV 1降低10%所需的呼吸热交换（PD 10 RHE），对乙酰甲胆碱的反应表示为使FEV 1降低20%所需的激发浓度（PC 20乙酰甲胆碱）。PD 10 RHE与PC 20呈直线正相关（r = 0.86，p <0.001）。对每种药物的反应性是高度可重复的。所有21名有哮喘症状的受试者均可测量PD 10 RHE，2名正常受试者可通过外推获得PD 10 RHE，但3名有哮喘既往史的受试者无法测量。当前哮喘患者的PC 20为6.3 mg/ml或更低，2名非哮喘受试者的PC 20为14和16 mg/ml，既往哮喘患者的PC 20在26和54 mg/ml之间。结果表明，非特异性支气管反应性是影响支气管对冷空气反应的一个重要因素，无论是冷空气或乙酰甲胆碱是合适的刺激，以测量非特异性支气管反应性，和哮喘患者和非哮喘受试者之间观察到的支气管反应性的差异是符合定量的，而不是定性的反应性差异。
We compared bronchial responsiveness to isocapnic hyperventilation of cold dry air at -18 degrees C and 0% humidity with bronchial responsiveness to inhaled methacholine in 24 subjects with current or previous asthma and 2 nonasthmatics. Two inhalation tests with each agent were carried out in random order on 4 consecutive days. The response to cold air was expressed as the respiratory heat exchange required to reduce the FEV1 by 10% (PD10 RHE) and the response to methacholine as the provocation concentration required to reduce the FEV1 by 20% (PC20 methacholine). There was a close positive linear correlation between PD10 RHE and PC20 (r = 0.86, p less than 0.001). The responsiveness to each agent was highly reproducible. The PD10 RHE could be measured in all 21 subjects with current symptoms of asthma and it could be obtained by extrapolation in 2 normal subjects, but it could not be measured in 3 subjects with a past history of asthma. The PC20 in the current asthmatics was 6.3 mg/ml or less, in the 2 nonasthmatic subjects, it was 14 and 16 mg/ml, and in the previous asthmatics it was between 26 and 54 mg/ml. The results indicate that nonspecific bronchial responsiveness is an important factor influencing the bronchial response to cold air, that either cold air or methacholine are suitable stimuli to measure nonspecific bronchial responsiveness, and that the differences in bronchial responsiveness observed between asthmatics and nonasthmatic subjects are in keeping with a quantitative rather than a qualitative difference in responsiveness.