Ohe Masashi, Kishi Fujiya, Hizawa Nobuyuki
Department of General Medicine, Social Insurance Hospital, Sapporo, 062-8618, Japan.
Hokkaido Igaku Zasshi. 2010 Mar;85(2):97-103.
Dose-related curves of the airway responses to Methacholine by Astograph are frequently biphasic. That is, respiratory resistance (Rrs) increases slowly at first and rapidly after that. We proposed (-dGrs/dt)/Grs obtained by using Astograph as an index of dynamic property of the airway, which we suggested was related to a coefficient of the contraction or dilatation of the airway. Grs represents respiratory conductance. By calculating (-dGrs/dt)/Grs, we found that biphasic dose-related curves were composed of the slow and subsequently rapid contraction of the airways. And by mathematical analysis, we found that all segments of the airway contracted simultaneously at a uniform velocity. The combination of slow and rapid contraction explains three types of the airway responses, that is, the monophasic reactivity of the airway with slow contraction, the monophasic reactivity of the airway with rapid contraction and the biphasic reactivity of the airway with slow and subsequently rapid contraction. We found that the frequency of the monophasic reactivity of the airway with slow contraction was significantly higher in patients with COPD than in healthy subjects or in patients with mild asthma. But there was no significant difference in (-dGrs/dt)/Grs values among healthy subjects, patients with mild asthma and patients with COPD.
使用Astograph测定的气道对乙酰甲胆碱反应的剂量-反应曲线通常呈双相。也就是说，呼吸阻力（Rrs）起初缓慢增加，之后迅速增加。我们提出将使用Astograph测得的（-dGrs/dt）/Grs作为气道动态特性的指标，我们认为这与气道收缩或扩张系数有关。Grs代表呼吸传导率。通过计算（-dGrs/dt）/Grs，我们发现双相剂量-反应曲线由气道的缓慢收缩和随后的快速收缩组成。通过数学分析，我们发现气道的所有节段以均匀速度同时收缩。缓慢收缩和快速收缩的组合解释了三种气道反应类型，即气道缓慢收缩的单相反应性、气道快速收缩的单相反应性以及气道缓慢收缩随后快速收缩的双相反应性。我们发现，慢性阻塞性肺疾病（COPD）患者气道缓慢收缩的单相反应性频率显著高于健康受试者或轻度哮喘患者。但健康受试者、轻度哮喘患者和COPD患者之间的（-dGrs/dt）/Grs值无显著差异。
