Pulmonary Gas Exchange Abnormalities in Patients With Mild COPD

Completed

• Conditions: COPD

• Registration Number: NCT02346604
• Lead Sponsor: Queen's University

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2013-07
• Primary Completion: 2015-01
• Study Completion: 2015-01
• Study First Submitted: 2015-01-07
• Study First Submitted QC: 2015-01-20
• Study First Posted: 2015-01-27
• Status Verified: 2015-11
• Last Update Submitted: 2015-11-19
• Last Update Posted: 2015-11-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 22

Inclusion Criteria

• Stable symptomatic patients with GOLD grade 1B mild COPD;
• at least 50 years of age;
• a cigarette smoking history ≥20 pack-years;
• a Baseline Dyspnea Index focal score ≤9;
• 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

• clinically significant comorbidities;
• contraindications to exercise testing;
• history/clinical evidence of asthma;
• body mass index <18.5 or >30 kg/m2;
• use of supplemental oxygen.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
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

Name	Time	Method
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

Trial Locations

Locations (1)

Respiratory Investigation Unit at Kingston General Hospital; 🇨🇦 Kingston, Ontario, Canada