Sensitivity of FEV1 and indices of flow volume curve in the methacholine test.

Our aim was to asses the association between the decrease of FEV1 and the modifications of the indices (PEF, MEF25, MEF50 and MEF75% of FVC) during methacholine challenge. 105 patients of both sexes with mild bronchial asthma were included in this study and were subjected to methacholine test according to ATS standards. The results were analysed using analysis of variance (MANOVA), discriminant stepwise and multiple regression. The reduction of FEV1 induced by increasing dosage of methacholine was associated with a significant decrease of the other flow-volume curve indices but we can observe a different flow behaviour. The MEF50 was more significant during the first level of variations and the MEF75 and MEF25 being more significant during the subsequent phases. We conclude that the evaluation of the flow volume indices can be important for better study the site of action of methacholine.