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Updated: Mar 27, 2026
Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Impulse Oscillometry as a Predictor of Asthma Exacerbations in Young Children
Johannes Schulze1, Silke Biedebach, Martin Christmann
1Department of Allergy, Pulmonology and Cystic Fibrosis, Children's Hospital, Goethe University, Frankfurt am Main, Germany.
Insights
Impulse oscillometry (IOS) effectively predicts asthma exacerbations in young children, outperforming traditional lung function tests. This simple method identifies peripheral airway obstruction, indicating a higher likelihood of exacerbations even when symptoms are absent.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Asthma Research
Background:
- Previous studies identified predictors of pediatric asthma exacerbations (AEs) using spirometry measures like forced expiratory volume (FEV1) and bronchial hyperresponsiveness (BHR).
- A post-hoc analysis of a pediatric asthma study highlighted the need for better predictive tools for AEs.
Purpose of the Study:
- To prospectively identify predictors of AEs in children using impulse oscillometry (IOS).
- To compare the predictive capabilities of IOS with previously identified markers such as FEV1 and BHR.
Main Methods:
- Prospective study involving 75 children (4-7 years) with intermittent asthma.
- Pulmonary function, BHR (methacholine challenge), allergen testing, and IOS were measured during symptom-free periods.
- Receiver-operating characteristic (ROC) curves and logistic regression were used to determine predictive accuracy (AUC).
Main Results:
- IOS parameter Rrs5 showed the highest predictive accuracy (AUC 0.80) for AEs in 54 children.
- FEV1 (AUC 0.62) and BHR (AUC 0.61) also predicted AEs, but less effectively than IOS.
- Logistic regression combining all parameters achieved 86% accuracy in predicting individual AE risk.
Conclusions:
- Impulse oscillometry is a simple and effective method for predicting AEs in young children with asthma.
- Airway resistance measured by IOS is a superior predictor of AEs compared to FEV1 and methacholine testing.
- Peripheral airway obstruction during symptom-free periods is suggested by IOS findings, correlating with increased AE likelihood.
Background:
In a post-hoc analysis of a pediatric asthma study, we identified the predictors of asthma exacerbations (AEs) and related them to forced expiratory volume (FEV1), the FEV1/FVC ratio, and bronchial hyperresponsiveness (BHR).
Objectives:
We sought to detect predictors of AEs in a prospective study that utilizes impulse oscillometry (IOS) and to compare the results to previously determined predictors.
Methods:
A moderate AE was defined as an increased use of salbutamol during coughing episodes. Pulmonary function and BHR were measured during symptom- and medication-free periods. Additionally, allergen testing and IOS were included. To calculate the sensitivity and specificity of AE detection, a receiver-operating characteristic (ROC) curve was plotted, and accuracy was measured with the area under the ROC curve (AUC). A logistic regression analysis was used to predict the probability of an exacerbation.
Results:
Seventy-five pediatric patients (4-7 years of age) with intermittent asthma were included. In 69 patients, the following cut-off values demonstrated the best sensitivity and specificity combination for predicting an AE: FEV1 103.2% (AUC 0.62), BHR (PD20methacholine) 0.13 mg (AUC 0.61), and, in 54 children, Rrs5 0.78 kPa × l-1 × s (AUC 0.80). Logistic regression analysis demonstrated that the combination of all parameters predicted the individual risk of AEs with an accuracy of 86%.
Conclusions:
IOS, a simple method, predicted the probability of AEs in young children. Airway resistance, measured by IOS, was superior to FEV1 and methacholine testing. The current data suggest that peripheral airway obstruction is present during symptom-free periods and that these children more likely experience AEs.
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