Dyspnea in COPD: Relationship With Exacerbations Frequency

Study Overview
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Brief Summary
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The perception of breathlessness varies significantly among COPD patients with similar severity of airflow limitation; those with poorer perception report less exacerbations as compared to those with frequent exacerbations. Cross-sectional comparison of breathlessness perception in COPD patients with frequent exacerbations or without frequent exacerbations. To assess Breathlessness Perception the investigators will increase the ventilatory demand of the patients by CO2-rebreathing method.

Detailed Description
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The perception of breathlessness varies between individuals. This is a well-established concept in asthma, but mostly unexplored in COPD; the relationship between airflow limitation (FEV1, % ref.) and breathlessness (mMRC) is weak. The perception of breathlessness varies significantly among COPD patients with similar severity of airflow limitation; those with poorer perception report less exacerbations as compared to those with frequent exacerbations. It is a cross-sectional comparison of breathlessness perception in COPD patients with frequent exacerbations (≥2 or ≥1 with hospitalization in the previous year) or without frequent exacerbations (0 or 1 without hospitalization in the previous year). To assess Breathlessness Perception the investigators will increase the ventilatory demand of the patients by CO2-rebreathing method. CO2 rebreathing test will be conducted to evaluate the acute ventilatory response to CO2 inhalation used to estimate central chemoreceptor responsiveness in patients with the obstructive pulmonary disease. Simple descriptive statistics (unpaired T-test) and correlation analysis (bivariate and multivariate) will be used to analyze results.

Official Title
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Breathlessness Perception in COPD: Relationship With Exacerbation Frequency

Conditions
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Dyspnea

Intervention / Treatment
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* Procedure: Spirometry
* Procedure: CO Exhaled breath
* Procedure: P01
* Procedure: FeNO


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with diagnosis of COPD (Gold 2 or 3 or 4) >2 months from last exacerbation and no change in therapy Exclusion Criteria: patients on regular sedative drugs patients with neuromuscular diseases patients with respiratory failure and/or in long-term oxygen therapy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: No frequent exacerbators<br>Patients without exacerbations: 0 or 1 that did not required hospitalization in the previous year. Interventions: Spirometry Emogas analysis Modified Borg Dyspnea Scale CO Exhaled breath P01 FeNO | Procedure: Spirometry<br>* Before re-breathing (if the patient not performed one 6 months in advance).<br>* Other names: Inspiratory capacity (IC);Procedure: CO Exhaled breath<br>* In current smokers of both arms to confirm that the patient has not smoked in the past three hours and to asses the smoking status (heavy, moderate, light).<br>* Other names: COHb (%);Procedure: P01<br>* P01 is the negative airway pressure generated during the ﬁrst 100 ms of an occluded inspiration. It's an estimation of the neuromuscular drive to breathe.<br>Procedure: FeNO<br>* The measurement of fraction of exhaled nitric oxide during exacerbations of COPD is higher than normal.<br>|
| Active Comparator: Frequent exacerbators<br>Patients with frequent exacerbations: ≥2 or ≥1 if it required hospitalization in the previous year. Interventions: Spirometry Emogas analysis Modified Borg Dyspnea Scale CO Exhaled breath P01 FeNO | Procedure: Spirometry<br>* Before re-breathing (if the patient not performed one 6 months in advance).<br>* Other names: Inspiratory capacity (IC);Procedure: CO Exhaled breath<br>* In current smokers of both arms to confirm that the patient has not smoked in the past three hours and to asses the smoking status (heavy, moderate, light).<br>* Other names: COHb (%);Procedure: P01<br>* P01 is the negative airway pressure generated during the ﬁrst 100 ms of an occluded inspiration. It's an estimation of the neuromuscular drive to breathe.<br>Procedure: FeNO<br>* The measurement of fraction of exhaled nitric oxide during exacerbations of COPD is higher than normal.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The negative airway pressure generated during the ﬁrst 100 ms of an occluded inspiration, which is an estimation of the neuromuscular drive to breathe. (P01 ) |  | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Borg scale | 10-point subjective scoring system, in which a patient rates his/her effort of exertion. | Baseline | 
| Fractional exhaled nitric oxide (FeNO) |  | Baseline | 
| Inspiratory capacity (IC) | The sum of inspiratory reserve volume and tidal volume. | Baseline | 
| Ventilation at rest |  | Baseline | 
| CO exhaled test | Testing for Carbon Monoxide in exhaled breath in current smokers. | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Dyspnea perception, COPD, Exacerbations, CO2 rebreathing test