Obstructive Lung Disease Is About More Than Just Airways: Blood Supply Matters

Abstract

Within their small air sacs, our lungs exchange oxygen (O2) from the air for the carbon dioxide (CO2) produced by our bodies. In these air spaces, O2 moves into small blood vessels while CO2 moves from the blood out into the air. Lung diseases can impair airflow and reduce the number of blood vessels in the lungs, making it harder to take in O2 and eliminate CO2. These changes to the lungs contribute to symptoms like breathlessness. The relationship between airflow and blood flow in our lungs is called V/Q, where V is for ventilation—the movement of air—and Q is for perfusion—blood flow to the lungs. While people with healthy lungs have good a good match between V and Q, those with certain lung diseases often have poor V/Q matching. In this article, we describe the origins of V/Q mismatch and its impact on lung function.