ABSTRACT
Objective To discuss the characteristics of pulmonary function in children patients with positive bronchodilating response using impulse oscillation system(IOS) and provide the evidence for clinical diagnosis and performing IOS.Methods Seventy children patients with bronchodilating response using IOS were recruited randomly for this study.Forty children patients with positive bronchodilating response were regarded as positive group and the other thirty children patients with negative bronchodilating response were regarded as negative group.The IOS parameters,for example,total respiratory impedance (Z5),respiratory resistance at 5 Hz(R5),reactance at 5 Hz(X5),peripheral respiratory resistance(Rp) in the two groups were analyzed.Results Z5,R5,X5 of the positive group [(123.45 ± 24.75)％,(120.09 ± 25.40)％,(138.62 ± 33.48)％] were higher than those of the negative group [(103.89 ± 16.30)％,(102.67 ± 18.16)％,(111.85 ± 14.93)％].There were significantly different between the two groups (P ＜ 0.05).Moreover,Rp ≥ 19.89 cmH2O/ (L·s)(1 cmH2O =0.098 kPa) in the positive group was 50.00％(20/40),which was higher than that in the negative group[23.33％(7/30)].There was significant difference between the two groups(P＜ 0.05).Conclusions The impedance of children patients with positive bronchodilating response using IOS is significantly increased,especially X5.When IOS parameters ≥ 100％,especially X5 ≥ 100％,which suggest that perform the bronchodilation test in order to decrease the rate of missed diagnosis of asthma.
ABSTRACT
PURPOSE: The normal values for lung resistance and lung capacity of children, as determined by impulse oscillometry (IOS), are different for children of different ethnicities. However, reference values there is no available reference value for Korean preschool children have yet to be determined. The aim of the present study was to determine the normal ranges of IOS parameters in Korean preschool children. METHODS: A total of 133 healthy Korean preschool children were selected from 639 children (aged 3 to 6 years) who attended kindergarten in Seongnam, Gyeonggi province, Korea. Healthy children were defined according to the European Respiratory Society (ERS) criteria. All subjects underwent lung function tests using IOS. The relationships between IOS value (respiratory resistance (Rrs) and reactance (Xrs) at 5 and 10 Hz and resonance frequency (RF)) and age, height, and weight were analyzed by simple linear and multiple linear regression analyses. RESULTS: The IOS success rate was 89.5%, yielding data on 119 children. Linear regression identified height as the best predictor of Rrs and Xrs. Using stepwise multiple linear regressions based on age, height, and weight, we determined regression equations and coefficients of determination (R2) for boys (Rrs5=1.934-0.009xHeight, R2=12.1%; Xrs5=0.774+0.006xHeight-0.002xAge, R2=20.2% and for girls (Rrs5=2.201-0.012xHeight, R2=18.2%; Xrs5=-0.674+0.004xHeight, R2=10.5%). CONCLUSION: This study provides reference values for IOS measurements of normal Korean preschool children. These provide a basis for the diagnosis and monitoring of preschool children with a variety of respiratory diseases.