Impulse Oscillometry Testing in Chronic Cough in Children

Introduction

Persistent cough is relatively common in children. It is estimated that 2 billion US$ per year is spent in the United States alone on cough and cold remedies.1 The cough is a symptom that causes a significant degree of distress to the sufferer and leads to increased parental anxiety.2

Abstract

INTRODUCTION

Chroni cough is a troublesome problem for children and the investigation to identify the underlying etiology is often inclusive.

OBJECTIVE

To assess lung function in children with chronic cough using impulse oscillometry (IOS).

METHODS

Sixty-seven children with chronic cough and 35 other children using age- and sex-matched controls were enrolled in this randomized control study. Patients and controls were subjected to IOS at the study entrance.

RESULTS

Airway resistance did not differ between cases and controls at baseline. Both cases and controls displayed significant reduction in resistance following bronchodilation; however, this was significantly more in cases (median ΔR5 Hz%: controls=−17.5, range: −45.1 to −8.7, cases=−6.4, range: −20.8 to −1.1, P<.001, median ΔR20 Hz%: controls=−11.5, range:−37.6 to −5.4, cases: −1.8, range:−20.1 to −0.4, P<.001, median ΔX5 Hz%: controls: −23.1, range: −48.6 to −9.9, cases: −8.6, range: −34.2 to −2.4, P=.01, median ΔZ5 Hz%: controls=−17.4, range: −44.8 to −9.8, cases: −6.8, range: −27.0 to −4.9, P<.001).

CONCLUSION

A proportion of patients with chronic cough tend to respond to bronchodilators by a significant reduction in airway resistance, as measured with IOS; an observation that supports an empirical trial of bronchodilators.

Keywords

impulse oscillometry, lung function, children, chronic cough