Pulmonary and Total Blood Volume in COPD

Background Patients with chronic obstructive lung disease (COPD) suffer from a progressive loss of lung function that leads to poor quality of life, and often invalidity and early death. This is markedly affected by a reduced exercise capacity and dyspnoea, but the underlying mechanisms are unknown. In the present study, we aim to investigate whether this may involve a reduced pulmonary blood volume secondarily to a reduced total blood volume. Methods Design: Prospective matched comparative study Intervention: None Outcomes: The primary outcome is pulmonary blood volume estimated to total blood volume ratio between patients with COPD and healthy controls individually matched for age, sex, and height. Statistical design: All statistical analyses will be performed using R statistical software version 4.1.1 (R Project for Statistical Computing) within RStudio statistical software version 1.4.1717 (RStudio), and a two-tailed p\<0.05 will be considered statistically significant. Inspection of normality and variance homogeneity will be done by creating qq-plots and histogram. Regulatory considerations: This study will be submitted for approval by Regional Ethical Committee. Perspective: This study will help uncover fundamental aspects of the pathophysiology of COPD.