Comparison of Changes Among Airway Resistance, Peak Expiratory Flow Rate, Forced Expiratory Volume in One Second

Son, Byong Kwan; Kim, Jung Hee; Lim, Dae Hyun; Kim, Jeung Gyu

Abstract

PURPOSE
We usually measure the changes of peak expiratory flow rate (PEFR) or forced expiratory volume in one second (FEV1) to check the bronchial response after inhalation of bronchodilator. Airway resistance determined by interrupter technique (Rint) is simple and easily applicable even to the infant. A comparison among PEFR, FEV1 and Rint was done to find out the feasibility of using Rint instead of PEFR or FEV1 in checking the bronchial response after inhalation of bronchodilator.
METHODS
We checked PEFR, FEV1, Rint, and oxygen saturation with twenty eight asthmatic children, over 7 years old, visited emergency or out patient department with acute asthmatic attack. The same parameters were checked in 5, 10, 20 minutes after inhalation of bronchodilator. Comparison and relationship of measures as well as changes of measures after inhalation of bronchodilator among them were analyzed to confirm if Rint can replace PEFR or FEV1 in checking bronchial response after inhalation of bronchodilator.
RESULTS
PEFR, FEV1 and O2 saturation increased as time goes on but airway resistance decreased. The relationship among the changes of parameters of PEFR, FEV1 and Rint checked in 5, 10 and 20 minutes after inhalation of bronchodilator showed close correlation with was statistically significant. But, the measures checked in 20 minutes after inhalation statistically insignificant.
CONCLUSION
Rint can be used instead of PEFR and FEV1 in checking the bronchial response after inhalation of bronchodilator.