Validation of a Single Concentration Methacholine Inhalation Provocation Test (SCIPT) in Children

A new method to assess bronchial hyperresponsiveness (BHR) using a single concentration methacholine has already been validated in adults with asthma. Because the geometrical dimensions of the airways in children are different, the results from studies in adults cannot be extrapolated to children. In this study, we validated the single concentration methacholine inhalation provocation test (SCIPT) in children. Twenty-two children performed three methacholine inhalation challenge tests in random order. Two challenges were performed according to the SCIPT: doubling doses (0.03–1.8 mg; maximal cumulated dose 3.6 mg) were administered with an Aerosol Provocation System (Masterscope, Jaeger). The third challenge was performed according to a standard dosimeter method (SDM): doubling doses (0.002–1.8 mg; maximal cumulative dose 3.5 mg) were administered with a DeVillbiss 646 nebulizer. The degree of BHR is expressed as a PD20. A difference of < 1.5 dose step was assumed to be due to intraindividual variation. We...