摘要
吸入蒸馏水可引起哮喘患者支气管收缩和对甲胆碱的短暂敏感性增加。本研究的目的是确定经诱导的支气管收缩在蒸馏水刺激后对甲胆碱敏感性增加中的作用。18例哮喘患儿(9-17岁)因吸入蒸馏水而受到刺激。在吸入蒸馏水前、吸入1.5 h和吸入24 h后测定支气管反应性,即甲胆碱激发浓度使1秒用力呼气量(PC20)减少20%。吸入蒸馏水后,8例患者(I组)1次FEV1下降幅度大于15%(平均23%);然而,其余10例(ⅱ组)的降幅小于7%(平均1%)。PC20与甲胆碱的几何平均值和95%置信区间(CI)仅在吸入蒸馏水1.5小时后短暂下降。从0.78毫克开始下降。(95% CI 0.11-5.54 mg.ml-1)基线为0.25 mg.ml-1。I组攻毒后ml-1 (95% CI 0.03-2.14 mg.ml-1); and from 2.67 mg.ml-1 (95% CI 0.35-20.34 mg.ml-1) at baseline to 0.72 mg.ml-1 (95% CI 0.18-14.87 mg.ml-1) after challenge in Group II. The transient increase in sensitivity to methacholine observed following inhalation of distilled water occurred independently of the bronchoconstrictive response. This finding may have important clinical implications when hypo-osmolar solutions are used for delivery of drugs.