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Conducting Respiratory Oscillometry in an Outpatient Setting
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Assessing direct and indirect airway hyperresponsiveness in children using impulse oscillometry
Satu Kalliola1, L Pekka Malmberg1, Merja Kajosaari2
1Skin and Allergy Hospital, Helsinki University Central Hospital, Helsinki, Finland.
Insights
Impulse oscillometry (IOS) effectively identifies airway hyperresponsiveness (AHR) in young children. Methacholine and exercise challenges using IOS can help diagnose probable asthma in children with lung symptoms.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Diagnostic Tools
Background:
- Airway hyperresponsiveness (AHR) is a key asthma indicator, but spirometry is challenging for young children.
- Impulse oscillometry (IOS) offers a less cooperative method for lung function assessment in pediatric populations.
Purpose of the Study:
- To determine if IOS-based AHR assessment can distinguish between pediatric obstructive symptom groups.
- To evaluate the utility of IOS in diagnosing respiratory conditions in young children.
Main Methods:
- 121 children (median age 6.0 years) with probable asthma, early wheezing, bronchopulmonary dysplasia, and controls underwent IOS.
- Direct AHR assessed via methacholine challenge; indirect AHR via exercise and mannitol challenges.
- A 40% increase in respiratory resistance at 5 Hz defined AHR.
Main Results:
- Exercise challenge with IOS differentiated children with current lung symptoms from others (P < .001).
- Methacholine challenge using IOS distinguished probable asthma, early wheezing, and BPD groups from controls (P < .001).
- Mannitol challenge did not differentiate study groups (P = .209).
Conclusions:
- Methacholine and exercise challenge tests using IOS are practical tools for evaluating AHR in young children.
- These IOS-based tests aid in identifying probable asthma in children with troublesome lung symptoms.
Background:
Airway hyperresponsiveness (AHR) is a hallmark of asthma but its assessment is usually restricted to older children who are capable of performing the maneuvers involved in spirometry. In younger children, a feasible option to perform the lung function measurement is impulse oscillometry (IOS), which requires less cooperation.
Objective:
To evaluate whether assessment of AHR by IOS could differentiate children with various obstructive symptoms from one another.
Methods:
One hundred twenty-one children (median age 6.0 years, range 3.7-8.1 years) were examined: 31 with probable asthma characterized by current troublesome lung symptoms, 61 with a history of early wheezing disorder (recurrent wheezing ≤24 months of age), 15 with a history of bronchopulmonary dysplasia, and 14 healthy controls. Indirect AHR was assessed by exercise and mannitol challenge tests, and direct AHR was assessed with methacholine using IOS. AHR to exercise was defined as an increase of at least 40% in respiratory resistance at 5 Hz. In the mannitol and methacholine challenges, the dose causing an increase of 40% in respiratory resistance at 5 Hz was calculated.
Results:
AHR to exercise was good at differentiating children with current troublesome lung symptoms from those in the other groups (P < .001). AHR to methacholine separated children with current troublesome lung symptoms, early wheezing disorder, and bronchopulmonary dysplasia from the controls (P < .001), whereas the mannitol test did not distinguish among the study groups (P = .209).
Conclusion:
The methacholine and exercise challenge tests with IOS identify children with probable asthma characterized by troublesome lung symptoms and therefore may represent a practical aid in the evaluation of AHR in young children.
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