Discriminant analysis of asthmatic patients and healthy adults using maximal expiratory indices

The selection of effective maximal expiratory was evaluated using discriminant analysis of asthmatic patients and healthy adults in this review. Maximal expiratory volume-time and flow-volume (MEVT and MEFV) curves were drawn for young non-smoking healthy subjects and for young male non-smoking asthmatic patients. Eleven indices, two MEVT (%FVC and FEV(1.0%)), six MEFV (PEFR, Flow(75), Flow(50), Flow(25), Flow(10) and Flow(50)/Flow(25)) and three mean time constant (MTC) indices (MTC(75-50), MTC(50-25) and MTC(25-RV)) were used for the discriminant analysis using an all possible selection procedure (APSP). In the eleven-indices discriminant analysis using a single index, Flow(75), Flow(50) and Flow(25) were effective indices. In the discriminant analysis through APSP, PEFR, Flow(75), MTC(75-50) and FEV(1.0%), which were at high lung volumes, were the set of the most effective four indices. These four indices appear to be effective in assessing bronchial asthma through a visual evaluation of MEFV curves. Therefore, discriminant analysis is appropriate in assessing the MEFV curves.