Effects of CPAP in Severe Therapy-resistant Asthma

Study Overview
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Brief Summary
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The purpose of this study is to verify the effects of continuous positive airway pressure (CPAP) on exercise capacity of children and adolescents with severe therapy-resistant asthma (STRA). A randomized, controlled, crossover clinical trial will be conducted. We expect the use of CPAP to increase exercise capacity in children and adolescents with STRA.

Detailed Description
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This project aims to verify the effects of continuous positive airway pressure (CPAP) on exercise capacity of children and adolescents with severe asthma therapy-resistant (STRA). A randomized, controlled, crossover clinical trial will be conducted. Children and adolescents between 6 and 18 years old, with a diagnosis of STRA, will be included in the study. Patients wil be recruited in the São Lucas Hospital (HSL) Asthma Outpatient Clinic of the Pontifical Catholic University of Rio Grande do Sul. Patients who accept to participate in the study will perform a medical consultation according to routine outpatient asthma clinic, anthropometric evaluation and pulmonary function tests. Afterwards, they will be randomized into control and intervention groups. Participants in the intervention group will use noninvasive ventilation (NIV) in CPAP mode with 10cmH2O of positive end-expiratory pressure (PEEP), fraction of inspired oxygen (FiO2) of 0.21, for a period of 40 minutes. Participants in the control group will use NIV (CPAP), with a minimum PEEP of 1cmH20 and a FiO2 of 0.21 also for 40 minutes. Afterwards, patients from both groups will perform a maximum cardiopulmonary exercise test (CPET). A sample size of 18 individuals to be included in the study was estimated. The variables studied will be maximal oxygen consumption and the anaerobic threshold (that measures exercise capacity), distance and time (to measure exercise tolerance), peripheral oxygen saturation, peak expiratory flow and the sensation of dyspnea at the end of the CPET.

Official Title
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Effects of Continuous Positive Airway Pressure (CPAP) on Exercise Capacity of Children and Adolescents With Severe Therapy-resistant Asthma

Conditions
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Asthma

Intervention / Treatment
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* Device: Continuous Positive Airway Pressure (CPAP)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Individuals with a clinical diagnosis of severe therapy-resistant asthma (STRA), of both sexes, aged between 6 and 18 years, who are under regular follow-up in the asthma outpatient clinic at São Lucas Hospital, PUCRS. The criteria for the classification of STRA is based on the Global Initiative for Asthma (GINA) guidelines: Asthma requiring treatment in steps 4-5 of GINA (≥800 mg/day of budesonide or equivalent, associated with long-acting ß2-adrenergic agonist (LABA); Use of continuous oral corticoid or omalizumab, presenting uncontrolled disease; Uncontrolled disease characterized by: 1) persistent symptoms or asthma control test (ACT) <20 (> 3 months); 2) acute exacerbations (with intensive care unit admission, at least 2 hospitalizations, or 2 courses of oral corticoid over the last 12 months); Or 3) non-reversible obstruction of pulmonary function, even after corticoid use. Exclusion Criteria: - Subjects with cognitive/motor limitations or other chronic diseases (neurological diseases, cardiac anomalies, congenital or immunodeficiencies), which may compromise the evaluation of asthma, as well as the procedures proposed by the present study.

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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Patients will be randomized, through a sealed envelope, to initially compose the intervention group or the control group. The sequential order of randomization will be kept confidential with a single investigator, so that the other professionals involved and responsible for data collection will be blinded throughout the study period. Individuals who initially composed the intervention group will then perform, in a second moment, the procedures of the control group.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Continuous Positive Airway Pressure (CPAP)<br>Participants in the intervention group will use CPAP device, for a period of 40 minutes, with the following parameters: PEEP of 10cmH2O and FiO2 0.21. | Device: Continuous Positive Airway Pressure (CPAP)<br>* In the first moment, CPAP will be installed, and the researcher will hold a mask in the position in which it is coherent, explaining the method to the patient and allowing their gradual adaptation. Patients will adapt for a few minutes to make sure the mask is consistent with the specifications, so that the patient is comfortable. Participants in the intervention group will start with a PEEP of 1cmH2O that will increase by 2 cmH2O until a PEEP of 10 cmH2O is reached. Therefore, participants in the intervention group will remain with CPAP, PEEP of 10cmH2O, FiO2 0.21, for a period of 40 minutes.<br>|
| Placebo Comparator: CONTROL<br>Participants in the control group will use CPAP device, for a period of 40 minutes, with the following parameters: PEEP of 1cmH2O and FiO2 0.21. | Device: Continuous Positive Airway Pressure (CPAP)<br>* In the first moment, CPAP will be installed, and the researcher will hold a mask in the position in which it is coherent, explaining the method to the patient and allowing their gradual adaptation. Patients will adapt for a few minutes to make sure the mask is consistent with the specifications, so that the patient is comfortable. Participants in the intervention group will start with a PEEP of 1cmH2O that will increase by 2 cmH2O until a PEEP of 10 cmH2O is reached. Therefore, participants in the intervention group will remain with CPAP, PEEP of 10cmH2O, FiO2 0.21, for a period of 40 minutes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise capacity | Exercise capacity will be assessed by the VO2max, evaluated during a cardiopulmonary exercise test. Gas capture measurement will be performed by an ergospirometric system using a VO2000 (Medical Graphics Corporation, St. Paul, Minnesota-USA) gas analyzer, which provides information on ventilatory variables every 20s. | Immediately after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Exercise tolerance | Exercise tolerance will be assessed by measuring distance in the cardiopulmonary exercise test. | Immediately after intervention | 
| Exercise duration | Exercise tolerance will be assessed by measuring time in the cardiopulmonary exercise test. | Immediately after intervention | 
| Peripheral oxygen saturation | Peripheral oxygen saturation will be evaluated at rest, every 60s and at the end of the CPET using a portable pulse oximeter (Nonin®, Minneapolis, USA). | Immediately after intervention | 
| Peak expiratory flow | Peak expiratory flow will be assessed using a peak flow meter immediately after CPET. | Immediately after intervention | 
| Subjective feeling of dyspnea | Subjective feeling of dyspnea will be evaluated using the Modified Borg Scale, which uses a graduation from 0 to 10, at the end of the CPET. | Immediately after intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Asthma, Continuous positive airway pressure, Oxygen consumption