Different End Points for Bronchial Hyperactivity (BHR) Tests.

Study Overview
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Brief Summary
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Bronchial challenge tests (BCT) are being used to diagnose bronchial hyperactivity (BHR) and quantify its severity.In older children and adults, BCT is done using spirometry to measure the value of 20% fall in FEV1 as an indicator for positive reactivity. However, in young children and infants that cannot perform spirometry, other measurements are used as indicators for BHR. Traditionally, in these populations, appearance of wheezing on auscultation is used as the indicator for BHR. More recently, other measures like 50% increase in respiratory rate or 5% decreases in oxygen saturation are mentioned as possible options to determine positive BHR. Nevertheless, as these measurements probably measure different parameters they could vary in time of appearance. The investigators also noted that in older children who perform spirometry, the order of appearance of these different physiologic measures is not constant. Decrease in O2 saturation, appearance of wheezing and increase in respiratory rate (RR) do not all appear at the same time and not in the same order of events. Some children are noted to have a decrease in FEV1 without wheezing - those children can be difficult to diagnose as asthmatics in the primary care setting where asthma is being diagnosed on clinical grounds alone: wheezing and response to bronchodilators. Children who do not wheeze are difficult to diagnose and therefore, are not getting the appropriate treatment. Nevertheless, the data in current literature is very scant or not existing regarding these issues. Thus the investigators designed a study to prospectively try to answer the questions: do clinically significant differences exist in the concentration of the metacholine and / or adenosine at the time time of appearances of these parameters, what comes first, and if so, how does it affect the diagnosis and the severity assessment of HRA in different age groups?

Detailed Description
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Bronchial challenge tests (BCT) are being used to diagnose bronchial hyperactivity (BHR) and quantify its severity. In older children and adults, BCT is done using spirometry to measure the value of 20% fall in FEV1 as an indicator for positive reactivity. However, in young children and infants that cannot perform spirometry, other measurements are used as indicators for BHR. Traditionally, in these populations, appearance of wheezing on auscultation is used as the indicator for BHR. More recently, other measures like 50% increase in respiratory rate or 5% decreases in oxygen saturation are mentioned as possible options to determine positive BHR. Nevertheless, as these measurements probably measure different parameters they could vary in time of appearance. The investigators also noted that in older children who perform spirometry, the order of appearance of these different physiologic measures is not constant. Decrease in O2 saturation, appearance of wheezing and increase in respiratory rate (RR) do not all appear at the same time and not in the same order of events. Some children are noted to have a decrease in FEV1 without wheezing - those children can be difficult to diagnose as asthmatics in the primary care setting where asthma is being diagnosed on clinical grounds alone: wheezing and response to bronchodilators. Children who do not wheeze are difficult to diagnose and therefore, are not getting the appropriate treatment. Nevertheless, the data in current literature is very scant or not existing regarding these issues. Thus the investigators designed a study to prospectively try to answer the questions: do clinically significant differences exist in the time of appearances of these parameters and if so, how does it affect the diagnosis and the severity assessment of HRA in different age groups? in this study we measure the metacholine and / or adenosine concentration at the time when the following parameters appear (what comes first): 20% fall in FEV1, 5% fall in oxygen saturation, 50% rise in respiratory rate, wheezing heard by the investigators using stethoscope.

Official Title
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Different End Points for Bronchial Hyperactivity (BHR) Tests, What Comes First?

Conditions
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Bronchial Hyperreactivity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients referred for HRA trigger testing Exclusion Criteria: None

Ages Eligible for Study
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Minimum Age: 1 Month
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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Which of the outcome ends points measures comes first in the diagnosis of bronchial hypersensitiveness. | Increasing concentrations of Metacholine or adenosine inhalations are given until there are 20% fall in FEV1 and / or 5% decrease in saturation and / or 50% increase in RR. The concentrations on which these outcomes occur are measured. | On which metacholine and / or adenosine increasing concentrations, there are 20% fall in FEV1 and / or 5% decrease in saturation and / or 50% increase in RR. Which comes first. Time frame: each BHR tests last up to two hours. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Age influence on which comes first outcomes. | Age in years and months will be recorded. Age influence on the distribution of the main outcome - which comes first - will be calculated. | The time frame of the study: four years. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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BRONCHIAL CHALLANGE TEST, ASTHMA, METACHLINE, ADENOSINE