Sensitivity of Forced Oscillation Technique in Children With Asthma and Normal Spirometry

Study Overview
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Brief Summary
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Exhibiting variable airway obstruction is a key factor in the diagnosis of asthma but too often it is undetected by spirometry. Study hypothesis: The forced oscillation technique (FOT) will show airway obstruction in asthmatic children with normal spirometry pointing out its advantage in measuring AW obstruction in this population. We will conduct a prospective observational study in 6-18 years old children with the diagnosis of asthma and a normal spirometry results. Each subject will undergo evaluation including: asthma control questionnaire, spirometry, FOT and Fractional exhaled nitric oxide (FeNO) to assess the sensitivity of FOT in diagnosing airway obstruction in this circumstances.

Detailed Description
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Background: Asthma diagnosis and control are based on history of recurrent typical symptoms and variable airflow obstruction by by measuring maximal expiratory flows with spirometry. However, in many children with asthma spirometry can be normal. The forced oscillation technique (FOT) is a simple, noninvasive technique performed during tidal breathing that is relatively easy to apply. The objective of this study is to assess the sensitivity of FOT in children with asthma and normal spirometry. Study design: this will be a prospective observational study. Population: 6-18 years old children visiting the pediatric pulmonary clinic at the investigators institution with the diagnosis of asthma and normal spirometry results (FEV1 & FEV1/FVC >80% and FEF25-75>65%) either on treatment or before treatment. Study protocol: After obtaining written informed consent, participants will fill asthma control questionnaires. Family history and risk factors for asthma will be reviewed. Data on blood eosinophils and skin prick test for allergy will be collected from the medical files. Medication (controller and reliever) will be also documented. FOT will be measured using the TremoFlo C-100 Airwave Oscillometry System (Thorasys , Montreal, Quebec, Canada). R5, R20, R5-20 (resistances at the reported frequency), X5 (reactance at 5hz), AX5 (reactance area at 5hz), Fres (resonance frequency) will be reported. Fractional exhaled nitric oxide (FeNO) will be measured using the single breath exhalation technique.

Official Title
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Sensitivity of Forced Oscillation Technique (FOT) in Children With Asthma and Normal Spirometry

Conditions
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Asthma in Children

Intervention / Treatment
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* Device: Forced oscillation technique (FOT)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of asthma Must be able to perform spirometry and FOT tests Normal spirometry results (FEV1 & FEV1/FVC >80% and FEF25-75>65%) Exclusion Criteria: Chronic lung disease other than asthma Severe chronic medical condition such as heart failure, neuromuscular disease etc.

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| asthmatic children<br>Children with the diagnosis of asthma and normal spirometry results. Each subject will undergo evaluation including: asthma control questionnaire, spirometry, FOT and Fractional exhaled nitric oxide (FeNO). | Device: Forced oscillation technique (FOT)<br>* FOT will be measured using the TremoFlo C-100 Airwave Oscillometry System (Thorasys , Montreal, Quebec, Canada). R5, R20, R5-20 (resistances in the reported frequency), X5 (reactance in 5hz) and Ax5 (reactance area in 5hz) will be reported.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| R5 | Resistances at the frequency of 5 hertz in kilopascal per liter per second | One year | 
| R20 | Resistances at the frequency of 20 hertz in kilopascal per liter per second | One year | 
| R5-R20 | The difference between R5 to R20 in kilopascal per liter per second | One year | 
| Xrs 5 | Reactance at the frequency of 5 hertz in kilopascal per liter | One year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| FeNO | Fractional exhaled Nitric Oxide (parts per billion) | One year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Forced oscillation technique, Airway obstruction, Asthma