Comparison of doubling and quadrupling methacholine concentration regimens using the tidal volume method.

摘要

The methacholine challenge is commonly used to measure airway responsiveness. Two doubling concentration methods have been outlined by the American Thoracic Society: the tidal breathing method and the dosimeter method. Quadrupling concentrations are an option with the dosimeter method as a time-saving measure. We reasoned that the tidal volume method could also be performed with quadrupling concentrations and performed a study to compare doubling and quadrupling concentrations.Fifteen nonpregnant, nonlactating adults with asthma but no allergic or infectious exacerbations within more than 4 weeks were recruited to perform 2 methacholine challenges in random order at the same time of day within 1 week, one with doubling and one with quadrupling concentrations of methacholine. The study was approved by the University of Saskatchewan Ethics Committee, and signed informed consent was obtained.