In diagnosis or monitor of the airway obstruction in bronchial asthma, the measurement of FEV1 in the standard method because of its reproducibility and accuracy. But the measurement of peak expiratory flow(PEF) by peak flow meter is much simpler and easier than that of FEV₁ especially in children. Yet there have been still no data of the predicted normal values of PEF measured by peak flow meter in Korean children. This study was conducted to provide equations to predict the normal value of PEF and correlation between PEF and FEV1 in healthy children.

PEF was measured by MiniWright peak flow meter, and the forced expiratory volume and the maximum expiratory flow volume curves were measured by Microspiro HI 501(Chest Co.) in 346 healthy children (age:5-16 years, 194 boys and 152 girls) without any respiratory symptoms during 2 weeks before the study. The regression equations for various ventilatory parameters according to age and/or height, and the regression equations of FEV₁ by PEF were derived.

1. The regression equation for PEF(L/min) was:12.6×age(year)+3.4×height(cm)-263(R²=0.85) in boys, and 6×age(year)+3.9×height(cm)-293(R²=0.82) in girls. 2. The value of FEFmax(L/sec) derived from the maximum expiratory flow volume curves was multiplied by 60 to compare with PEF(L/min), and PEF was faster by 125 L/min in boys and 118 L/min in girls, respectively. 3. The regression equation for FEV₁(ml) by PEF(L/min) was:7×PEF-550(R²=0.82) in boys, and 5.8×PEF-146(R²=0.81) in girls, respectively.

This study provides regression equations predicting the normal values of PEF by age and/or height in children. And the equations for FEV1, a gold standard of ventilatory function, was predicted by PEF. So, in taking care of children with airway obstruction, PEF measured by the peak flow meter can provide useful information.