Evaluation of interrupter resistance in methacholine challenge testing in children

Marije Koopman (1) , Hein J.L. Brackel (2) , Anja A.P.H. Vaessen-Verberne (3) , Wim Cj Hop (4) , Cornelis K van Der Ent (1)

1 Pediatric Pulmonology
2 Pediatrics
3 Pediatrics
4 Department of Epidemiology & Biostatistics

Bronchial hyperresponsiveness is a key feature of asthma and is assessed using bronchial provocation tests. The primary outcome in such tests (a 20% decrease in forced expiratory volume in 1 second (FEV₁)) is difficult to measure in young patients. This study evaluated the sensitivity and specificity of the interrupter resistance (R_int) technique, which does not require active patient participation, by comparing it to the primary outcome measure. Methacholine challenge tests were performed in children with a history of moderate asthma and bronchial hyperresponsiveness. Mean and individual changes in R_int and FEV₁ were studied. A receiver operating characteristic (ROC) curve was used to describe sensitivity and specificity of R_int. Seventy-three children (median age: 9.2 yrs; range: 6.3- 13.4 yrs) participated. There was a significant (p< 0.01) increase in mean R_int with increasing methacholine doses. However, individual changes of R_int showed large fluctuations. There was great overlap in change of R_int between children who did and did not reach the FEV₁ endpoint. A ROC-curve showed an area under the curve of 0.65. Because of low sensitivity and specificity, the use of R_int to diagnose bronchial hyperresponsiveness in individual patients seems limited.

Mots clés: Medicine

Marije Koopman, Hein J.L. Brackel, Anja A.P.H. Vaessen-Verberne, Wim Cj Hop, Cornelis K van Der Ent. Evaluation of interrupter resistance in methacholine challenge testing in children. Pediatric Pulmonology, 2010, 46 (3), pp.266. ⟨10.1002/ppul.21362⟩. ⟨hal-00599815⟩