Usefulness of measuring peak expiratory flow rate for diagnosing the airway hyperresponsiveness in childhood

Hwang, Young Jun; Jin, Young A; Han, Man Yong; Chang, Wook; Lee, Kyu Hyung

Abstract

BACKGROUND: Airway hyperresponsiveness has been estimated by means of forced expiratory volume in 1 second(FEV1) through the methacholine inhalation challenge test(MIC). But it is difficult to do the forced expiratory maneuver for measuring FEV1 in children. It is relatively easy to measure peak expiratory flow rate(PEFR) by portable peak expiratory flow meter(PEFM).
OBJECTIVE
The purpose of this study is to evaluate whether FEV1 by means of MIC could be appropriately replaced by the measurement of PEFR. METHOD: A total of 30 subjects aged from 7 to 15 years with recurrent cough were enrolled in this study. MIC was performed with stepwise cumulative dose and both FEV1 and PEFR were measured at each step. The study was discontiued at the point of 20% reduction of FEV1 from the baseline value. FEV1 and PEFR were measured after salbutamol was inhaled by nebulizer. RESULT: There were significant correlations with reduction rates(r1=0.59, P<0.05) and recovery rates(r2=0.60, P<0.05) between FEV1 and PEFR, respectively. The sensitivity, specificity, positive predictive and negative predictive value of PEFR(PC20-FEV1 and PC20-PEFR<8 mg/ml) were 63.6, 94.7, 87.8 and 81.8%, respectively(P<0.05).
CONCLUSION
Although PEFR measurement by means of MIC revealed low sensitivity, high specificity and positive predictive value could be obtained. These results indicate that PEFR measurement by means of MIC may be useful for diagnosing the airway hyperresponsiveness in children, although it cannot be replaced completely.