Pulmonary Gas Exchange Abnormalities in Patients With Mild COPD
Study Details
Study Description
Brief Summary
People with mild chronic obstructive pulmonary disease (COPD) can have significant physiological abnormalities and breathing inefficiency which become more pronounced during the stress of exercise, leading to intolerable breathing discomfort (dyspnea). To better understand the mechanisms of respiratory symptoms and exercise limitation in mild COPD, we will examine detailed lung function tests and other important measurements during rest and exercise in people with mild COPD compared with healthy non-smokers. This will be the first study to uncover the fundamental causes of breathing inefficiency and the related shortness of breath during physical exertion in patients with mild COPD. We hope to demonstrate that one simple measurement during exercise [the relation (ratio) between the total amount of air breathed (ventilation) and the amount of carbon dioxide breathed out] gives meaningful information about the extent of damage to the small airways and blood vessels in mild COPD and the overall gas exchanging function of the lungs, without the need for an arterial blood sample.
This is a case-controlled observational study not involving an intervention. Participants will complete 2 visits approximately 1 week apart, each conducted at the same time of day. Visit 1 will consiste of screening for iligibility, symptom and activity assessments, pulmonary function tests and an incremental cycle cardiopulmonary exercise test (CPET) for familiarization purposes. Visit 2 will include spirometry followed by an incremental cycle CPET with detailed measures of ventilatory, gas exchange, sensory-perceptual and arterial blood gas responses.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
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Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Mild COPD Symptomatic smokers with mild COPD |
|
| Healthy Control Non-smokers, matched to mild COPD group for age (at least 50 years) and gender |
Outcome Measures
Primary Outcome Measures
- ventilatory equivalent for carbon dioxide (VE/VCO2) [Measured at its nadir during an exercise test. Participants will be followed for the amount of time taken to complete 2 study visits, an expected average duration between 1 and 2 weeks.]
Exercise will consist of a symptom-limited incremental test on a cycle ergometer
Secondary Outcome Measures
- dead space to tidal volume ratio (VD/VT) [Measured at standardized work rates during exercise]
- arterial blood gas measurements [Measured at standardized work rates during exercise]
Measurements will include arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), pH, hydrogen ion (H+), plasma bicarbonate (HCO3-) and lactate.
- dyspnea intensity measured using the modified 10-point Borg scale [Measured at standardized work rates during exercise]
Eligibility Criteria
Criteria
Inclusion Criteria:
-
Stable symptomatic patients with GOLD grade 1B mild COPD;
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at least 50 years of age;
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a cigarette smoking history ≥20 pack-years;
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a Baseline Dyspnea Index focal score ≤9;
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post-bronchodilator forced expiratory volume in 1 second (FEV1) ≥80 %predicted and an FEV1/forced vital capacity (FVC) ratio <0.7 and < lower limit of normal.
Exclusion Criteria:
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clinically significant comorbidities;
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contraindications to exercise testing;
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history/clinical evidence of asthma;
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body mass index <18.5 or >30 kg/m2;
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use of supplemental oxygen.
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Respiratory Investigation Unit at Kingston General Hospital | Kingston | Ontario | Canada | K7L 2V7 |
Sponsors and Collaborators
- Queen's University
- Ontario Lung Association
Investigators
- Principal Investigator: Denis E O'Donnell, MD, FRCPC, Queen's University and Kingston General Hospital
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- DMED-1458-12