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Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Small Airway Dysfunction Measured by Impulse Oscillometry and Fractional Exhaled Nitric Oxide Is Associated With
Liang-Mei Lin1, Yu-Jun Chang2, Kuender D Yang3,4
1Respiratory Therapy Section for Children, Changhua Christian Children's Hospital, Changhua, Taiwan.
Insights
Impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) effectively predict childhood asthma control. Combining these non-invasive measures enhances accuracy in identifying uncontrolled asthma, aiding early intervention.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Asthma Research
Background:
- Impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) are sensitive, non-invasive tools for assessing airway resistance and inflammation.
- Limited population-based studies exist on using IOS and FeNO to predict asthma control in children.
Purpose of the Study:
- To evaluate the utility of IOS and FeNO in assessing childhood asthma control.
- To investigate their role in identifying small airway dysfunction and airway inflammation.
Main Methods:
- A prospective observational cohort study included 5,018 school children (6-12 years), with 560 asthmatic and 140 controls.
- Measurements included FeNO, spirometry, IOS, bronchial dilation test, total IgE, and the Childhood Asthma Control Test (C-ACT).
- Correlations were analyzed between FeNO, IOS, spirometry, and C-ACT for controlled vs. uncontrolled asthma.
Main Results:
- Uncontrolled asthmatic children showed significantly abnormal FeNO, IOS, and spirometry values compared to controls (P < 0.05).
- IOS parameters (R5, R5-R20, X5, Ax, △R5) and FeNO predicted lower C-ACT scores (AUCs 0.609–0.714).
- Combined FeNO (>20 ppb) and IOS significantly improved specificity for predicting uncontrolled asthma versus FeNO alone (P < 0.01). Small airway parameter R5-R20 was a strong risk factor (OR: 87.26).
Conclusions:
- Combined FeNO and IOS measurements strongly predict childhood asthma control status.
- These non-invasive methods offer valuable insights into small airway dysfunction and inflammation in pediatric asthma.
Background:
Impulse oscillometry (IOS) and fractional exhaled nitric oxide (FeNO) are sensitive and non-invasive methods to measure airway resistance and inflammation, although there are limited population-based studies using IOS and FeNO to predict asthma control.
Objective:
This study aimed to investigate the utility of IOS and FeNO for assessing childhood asthma control in terms of small airway dysfunction and airway inflammation.
Methods:
This prospective observational cohort study enrolled 5,018 school children (aged 6-12 years), including 560 asthmatic children and 140 normal participants. FeNO, spirometry, IOS, bronchial dilation test, total IgE, and childhood asthma control test (C-ACT) were measured. FeNO, IOS, spirometry, and C-ACT results were correlated with childhood asthma with and without control.
Results:
Uncontrolled asthmatic children had abnormal FeNO, IOS, and spirometric values compared with control subjects (P < 0.05). IOS parameters with R5, R5-R20, X5, Ax, △R5, and FeNO can predict lower C-ACT scales by the areas under receiver operating characteristic curves (AUCs) (0.616, 0.625, 0.609, 0.622, 0.625, and 0.714). A combination of FeNO (>20 ppb) with IOS measure significantly increased the specificity for predicting uncontrolled asthma patients compared with FeNO alone (P < 0.01). A multiple regression model showed that small airway parameter (R5-R20) was the strongest risk factor [OR (95% CI): 87.26 (7.67-993.31)] for uncontrolled asthma patients. Poor control with lower C-ACT scales correlated with high FeNO (r = -0.394), R5 (r = -0.106), and R5-R20 (r = -0.129) in asthmatic children (P < 0.05).
Conclusion:
A combined use of FeNO and IOS measurements strongly predicts childhood asthma with or without control.
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