Friday, 16 October 2015
Hall D1 Foyer (Floor 3) (Coex Convention Center)
In Suk Sol, MD
,
Department of Pediatrics and Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
Yoon Hee Kim, MD
,
Department of Pediatrics and Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
Min Jung Kim, MD
,
Department of Pediatrics and Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
Seo Hee Yoon, MD, PhD
,
Department of Pediatrics and Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
Young a Park, MD
,
Department of Pediatrics and Institute of Allergy, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
Yong Ju Lee, MD
,
Hallym Sacred Heart Kangnam Hospital, Seoul, South Korea
Kyung Won Kim, MD, PhD
,
Department of Pediatrics and Institute of Allergy, Yonsei University College of Medicine, Seoul, South Korea
Myung Hyun Sohn, MD, PhD
,
Department of Pediatrics and Institute of Allergy, Yonsei University College of Medicine, Seoul, South Korea
Kyu-Earn Kim, MD, PhD
,
Department of Pediatrics and Institute of Allergy, Yonsei University College of Medicine, Seoul, South Korea
Background: Impulse Oscillometry (IOS) was developed as a non-invasive method to evaluate lung function by measuring respiratory resistance and reactance. Respiratory resistance and reactance were measured over tidal breaths (whole-breath analysis) and measured separately during inspiration and expiration (inspiratory-expiratory analysis). It was known that reactance from inspiratory-expiratory analysis can detect expiratory flow limitation. We investigated characteristics of inspiratory-expiratory measurement obtained by IOS in children with asthma.
Methods: We enrolled 96 children with asthma (66 male) and 30 healthy controls (16 male) aged 4 to 18 yrs. All children with asthma were diagnosed in accordance with ATS/ERS guideline. Spirometry and whole-breath and inspiratory-expiratory impulse oscillometry were performed in all enrolled children. The measurements were assessed in asthmatic children compared to control subjects.
Results: In whole-breath IOS analyses, asthmatic children had increased resistance at 5Hz (0.82 ± 0.3 vs. 0.69 ± 0.2 kPa/L/s, P = 0.009), increased R5－R20 (0.64 ± 0.17 vs. 0.54 ± 0.15 kPa/L/s), decreased reactance at 5 Hz (－0.42 ± 0.2 vs.－0.3 ± 0.14 kPa/L/s, P = 0.001), and increased reactance area (AX) (3.3 ± 1.8 vs. 2.3 ± 1.2 kPa/L, P = 0.001) than control subjects. In inspiratory-expiratory IOS analysis, expiratory AX was higher than inspiratory AX in both asthmatic children (3.5 [2.4 – 4.8] vs. 2.8 [1.8 – 3.7] kPa/L, P < 0.001) and control subjects (2.2 [1.5 – 3.4] vs. 2.0 [1.2 – 3.0] kPa/L, P = 0.02). The change in AX between expiration and inspiration (DAX) was larger in asthmatic children compared to control subjects (－0.56 [－1.5 - －0.1] kPa/L vs. －0.27 [－0.71 - －0.18] kPa/L, P = 0.023). Whereas the change in X5 between expiration and inspiration (DX5) was not significant between asthmatic children and control subjects (0.1 [0.03 – 0.28] vs.0.09 [0.01 – 0.17] kPa/L/s, P = 0.231).
Conclusions: Children with asthma significantly differed from healthy controls in whole-breath impulse oscillometry. Larger inspiratory-expiratory variation in AX analysis asthmatic children than control subjects could reflect airway narrowing on expiration in childhood asthma.
Key words: Impulse oscillation system, Asthma, whole-breath analysis, inspiratory-expiratory analysis
