Pulmonary Gas Exchange Abnormalities in Patients With Mild COPD

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.

Study Overview

• Status: Completed
• Conditions: COPD

• Study Type: Observational
• Enrollment (Actual): 22

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Kingston, Ontario, Canada, K7L 2V7
      • Respiratory Investigation Unit at Kingston General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients fitting GOLD grade 1B criteria for mild COPD

Description

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 Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Mild COPD; Symptomatic smokers with mild COPD
Healthy Control; Non-smokers, matched to mild COPD group for age (at least 50 years) and gender

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ventilatory equivalent for carbon dioxide (VE/VCO2)	Exercise will consist of a symptom-limited incremental test on a cycle ergometer	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.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
dead space to tidal volume ratio (VD/VT)		Measured at standardized work rates during exercise
arterial blood gas measurements	Measurements will include arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), pH, hydrogen ion (H+), plasma bicarbonate (HCO3-) and lactate.	Measured at standardized work rates during exercise
dyspnea intensity measured using the modified 10-point Borg scale		Measured at standardized work rates during exercise

Collaborators and Investigators

• Sponsor: Queen's University
• Collaborators: Ontario Lung Association
• Investigators: Principal Investigator: Denis E O'Donnell, MD, FRCPC, Queen's University and Kingston General Hospital

Study record dates

Study Major Dates

• Study Start: July 1, 2013
• Primary Completion (Actual): January 1, 2015
• Study Completion (Actual): January 1, 2015

Study Registration Dates

• First Submitted: January 7, 2015
• First Submitted That Met QC Criteria: January 20, 2015
• First Posted (Estimate): January 27, 2015

Study Record Updates

• Last Update Posted (Estimate): November 20, 2015
• Last Update Submitted That Met QC Criteria: November 19, 2015
• Last Verified: November 1, 2015

More Information

Terms related to this study

• Keywords: exercise
• Additional Relevant MeSH Terms: Congenital Abnormalities
• Other Study ID Numbers: DMED-1458-12