Avoiding deep inspirations increases the maximal response to methacholine without altering sensitivity in non-asthmatics

作者：Chapman David G^*; King Gregory G; Berend Norbert; Diba Chantale; Salome Cheryl M

来源：Respiratory Physiology & Neurobiology, 2010, 173(2): 157-163.

DOI：10.1016/j.resp.2010.07.011

• Airway hyperresponsiveness
• Deep inspiration
• Asthma

Airway hyperresponsiveness is characterised by a leftward shift of the close-response curve (DRC) and an Increase in the maximal response Deep inspiration (DI) avoidance increases responsiveness in non-asthmatic, but not asthmatic, subjects The aim was to determine the effect of DI avoidance on the sensitivity and maximal response of the FEV(1) DRC to methacholine Thirteen non-asthmatic and ten asthmatic subjects underwent a standard cumulative high-dose methacholine challenge (0 1-200 mu mol) Subsequently, on separate days, increasing single closes of methacholine were administered after 10 min of DI avoidance A sigmoidal equation was fitted to the data to obtain values fora, the position constant, as a measure of sensitivity. The fall in FEV(1) at the highest common dose was used as a measure of the maximal response The change in flow at 40% control vital capacity on the maximal (V40m) and partial (V40p) curves were calculated from the first manoeuvre after methacholine and the ratio of the values for V40m and V40p was calculated as a measure of the bronchodilator effect of DI (BD(D1)) In non-asthmatic subjects. avoiding DI increased the maximum fall in FEV(1) at the highest common dose (p = 0 0001) but did not alter alpha (p = 0 75) Avoiding DI before challenge did not alter BD(D1) (p= 0 13) DI avoidance had no effect on airway responsiveness in asthmatic subjects. In non-asthmatic subjects. DI avoidance increases airway responsiveness by increasing

• 出版日期2010-9-30
• 单位河北医科大学