Corte P, Young I H
Chest. 1985 Aug;88(2):167-75. doi: 10.1378/chest.88.2.167.
Continuous distributions of ventilation-perfusion (VA/Q) ratios were measured in ten subjects with moderately severe symptomatic asthma. Six of the subjects had only minimal VA/Q inequality (mean log SD of bloodflow 0.5) despite having airways obstruction similar to that in the four subjects with marked VA/Q inequality (mean log SD of bloodflow 1.0). The six patients with minimal VA/Q inequality developed marked widening of their VA/Q distributions while breathing 100 percent oxygen (mean log SD bloodflow 1.1), and four of these patients maintained more modest widening after receiving an intravenous antihistamine, clemastine (mean log SD bloodflow 0.75). The four subjects with a wide control VA/Q distribution showed smaller changes while breathing pure oxygen and no change after receiving clemastine. FEV1 improved with clemastine treatment in the first four patients only. The results suggest that the majority of patients with moderately severe asthma have compensatory pulmonary vasoconstriction, causing better VA/Q matching which is responsive to hypoxia and, possibly, histamine. The data demonstrate a relationship between active compensatory vasoconstriction and airway sensitivity to antihistamine.
对10名中度严重症状性哮喘患者的通气-灌注（VA/Q）比值的连续分布进行了测量。其中6名受试者尽管存在与4名VA/Q比值明显不均等（血流平均对数标准差为1.0）的受试者相似的气道阻塞，但仅有最小程度的VA/Q不均等（血流平均对数标准差为0.5）。6名VA/Q不均等程度最小的患者在吸入100%氧气时其VA/Q分布明显变宽（血流平均对数标准差为1.1），其中4名患者在接受静脉注射抗组胺药氯马斯汀后保持了较适度的变宽（血流平均对数标准差为0.75）。4名对照VA/Q分布较宽的受试者在吸入纯氧时变化较小，接受氯马斯汀后无变化。仅前4名患者的FEV1在氯马斯汀治疗后有所改善。结果表明，大多数中度严重哮喘患者存在代偿性肺血管收缩，导致更好的VA/Q匹配，这对缺氧以及可能对组胺有反应。数据表明了活跃代偿性血管收缩与气道对抗组胺药敏感性之间的关系。
