Assessing Asthma Control by Impulse Oscillometry and Fractional Expiratory Nitric Oxide in Children With Normal Spirometry

Hee-Jeong Yun; Sang-Yong Eom; Youn-Soo Hahn

doi:10.1016/j.jaip.2023.04.039

Assessing Asthma Control by Impulse Oscillometry and Fractional Expiratory Nitric Oxide in Children With Normal Spirometry

J Allergy Clin Immunol Pract. 2023 Sep;11(9):2822-2829.e1. doi: 10.1016/j.jaip.2023.04.039. Epub 2023 May 11.

Authors

Hee-Jeong Yun¹, Sang-Yong Eom², Youn-Soo Hahn³

Affiliations

¹ Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea.
² Department of Preventive Medicine, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea.
³ Department of Pediatrics, College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Korea. Electronic address: yshahn@chungbuk.ac.kr.

PMID: 37178768
DOI: 10.1016/j.jaip.2023.04.039

Abstract

Background: Because spirometric parameters fail to address current status of asthma in some patients, additional tests are required for better evaluation of asthma.

Objective: We aimed to test the ability of impulse oscillometry (IOS) and fractional expiratory nitric oxide (FeNO) in identifying inadequately controlled asthma (ICA) that was not uncovered by spirometry.

Methods: Recruited asthmatic children between ages of 8 and 16 years underwent spirometry, IOS, and FeNO measurements on the same day. Only subjects who had spirometric indices within normal range were included. Asthma Control Questionnaire-6 scores of 0.75 or lower and greater than 0.75 indicated well-controlled asthma (WCA) and ICA. Percent predicted values of IOS parameters and IOS reference values for upper and lower limits of normal (>95th and <5th percentiles, respectively) were calculated on the basis of previously published equations.

Results: There were no significant differences in all spirometric indices between the WCA (n = 59) and the ICA (n = 101) groups. The % predicted values of IOS parameters except resistance at 20 Hz (R20) were significantly different between the 2 groups. Receiver operating characteristic analysis showed that the highest and lowest areas under the curve were 0.81 and 0.67 for the difference between the resistances at 5 Hz and 20 Hz (R5-R20) and R20 in discrimination of ICA versus WCA. The areas under the curve for IOS parameters were improved by combination with FeNO. The better discriminative ability of IOS was also supported by the higher values of the concordance index for the resistance at 5 Hz (R5), R5-R20, the reactance at 5 Hz (X5), and the resonant frequency of reactance than those for spirometric parameters. Compared with those with normal values, subjects with abnormal IOS parameters or high FeNO had significantly higher odds of having ICA.

Conclusions: The IOS parameters and FeNO were shown to be useful in identifying children with ICA when spirometry was normal.

Keywords: Asthma; Control; Fractional exhaled nitric oxide; Impulse oscillometry; Pediatric; Spirometry.

MeSH terms

Asthma* / diagnosis
Child
Forced Expiratory Volume
Humans
Nitric Oxide*
Oscillometry
Respiratory Function Tests
Spirometry

Substances

Nitric Oxide