[Study of PEFV curves in 520 normal middle-aged and old humans]

Partial expiratory flow-volume(PEEV) curves and other pulmonary functions were performed for 520 (20-86 yr) normal midde-aged and old humans. The regression equations of V at FRC (VFRC, volume corrected VFRC (VFRC/FVC), flows at various lung volumes (V75, V50, V25) and specific time constants (S tau 75, S tau 50, S tau 25) were built with multiple stepwise regression analysis. VFRC decreased with increase of age, but after correction with FVC, the correlation of VFRC/FVC with age decreased. The regressions were tested with substitution of parameters with normal persons and proved to be correct. This study suggests that PEFV curve with convenient method has theoretical and practical significance.