Impulse oscillometry (IOS) for detection of exercise induced bronchoconstriction in children with asthma ages 6–15 years

Abstract

Objectives

To determine the discriminatory value of various impulse oscillometry (IOS) parameters, and to find the cutoff value of the appropriate parameter for identifying exercise-induced bronchoconstriction (EIB) in children with asthma.

Methods

This cross-sectional study was conducted in India from October 2016 to March 2018 in children with asthma who were 6–15 years of age. One hundred and five children were enrolled and subjected to pre-exercise IOS and spirometry followed by free running treadmill test as an exercise challenge. All children could achieve minute ventilation >17.5–21 times of FEV₁ during the exercise challenge test. Then, IOS and spirometry were performed at 10 ± 2, 20 ± 2, and 30 ± 2 min post-exercise challenge. EIB was defined as reduction of FEV₁ ≥10% within 30 min of exercise. For purposes of analysis, the children were grouped into two categories: “EIB Present” or “EIB Absent”.

Results

The prevalence of EIB in our study was 20.95% (n = 22). ΔR5max percentage within 30 min post-exercise (AUC 0.74; 95% CI: 0.64, 0.84) had the best discriminating capacity among all IOS parameters for identifying EIB. A cutoff value of 14.1% increase in R5 within 30 min post-exercise was obtained for detection of EIB (sensitivity—95.45%, specificity—50.6%, PPV—33.87% and NPV—97.67%).

Conclusions

A percentage change in R5 with a cutoff value of 14.1% increase post-exercise had the best discriminatory capacity among all IOS parameters for detection of EIB in children with asthma. However, low positive predictive value (PPV) with high negative predictive value (NPV) made this cutoff value more apt to rule out EIB.

Keywords:

• EIB
• airway hyperresponsiveness
• early detection
• post-exercise
• R5
• FEV1

Acknowledgements

The authors thank all patients and the laboratory personnel in Pulmonary Function Test Laboratory, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi who contributed to this study. The authors thank Dr. Jitender Sodhi, Assistant Professor, Department of Hospital Administration, AIIMS, New Delhi for assistance in reviewing the language and grammar.

Authors’ contributions

All authors contributed to the study conception and design. Material preparation and data collection was done by Samriti Gupta. Data were analyzed by Aparna Mukherjee, Rakesh Lodha and Samriti Gupta. The first draft of the manuscript was written by Samriti Gupta and all authors commented on previous versions of the manuscript. All authors agreed to submit to the current journal, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Availability of data and material

The datasets generated during and/or analyzed during the current study are not available in the public domain, but could be obtained from the corresponding author on reasonable request.

Consent to participate

Written informed consent was obtained from the parents and assent was obtained from children >7 years of age.

Consent for publication

Written consent was taken from all participants for publishing the data.

Declaration of interest

The authors have no relevant financial or non-financial interests to disclose.

Ethics approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of All India Institute of Medical Sciences, New Delhi, India (Date—29–06-2016/No—372).

Funding

The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.