[Comparison of efficiency and merits of two parameters for bronchial challenge test by use of a simple equation]

The aim of this study was to investigate the relationship, merit and weakness of two parameters--the FEV1 and sGaw--for bronchial challenge test. The 36 cases of asthma patients were subjected to bronchial challenge test with FEV1 and sGaw as the test parameters simultaneously. A simple calculative equation was used. The Mch (challenge medicine) concentrations for a 20% decrease of FEV1(PC20FEV1) and for a 35% decrease of sGaw (PC35 sGaw) were figured out. The results showed that PC20 FEV1 and PC35 sGaw were 2.73 +/- 2.92 g/L and 1.50 +/- 2.03 g/L respectively. A significant difference between them was noted (P < 0.05), and their coefficient of correlation r = 0.738. The linear regression equation was PC35sGaw = 0.100 + 0.513 x PC20 FEV1. PC35sGaw was obviously lower than PC20 FEV1; the Mch amount for PC35sGaw was almost one half of that for PC20 FEV1, which indicated that sGaw was more sensitive than FEV1 as a parameter for bronchial challenge test. The FEV1, however, needs a relatively low standard of instrument, so it is more obtainable and popularized.