Grant: Project Grant

Our lungs are beautifully designed to get oxygen from the air while eliminating the carbon dioxide produced by the body. To achieve that, a balanced amount of air should meet the right amount of blood in each lung region. Several lung diseases may disturb this perfect match. Amongst them, smoking-induced chronic obstructive pulmonary disease (COPD)) stands out as a devastating cause of shortness of breath that affects millions of Canadians. Many persons with COPD start feeling winded even when their breathing tests say they have only a minor disease. Thus, they might be dismissed by their doctors, who frequently believe that lack of exercise is the only culprit. We discovered, however, that their shortness of breath can be caused by too much air breathed, even with a slight effort. To help these persons, we must learn what drives their excessive breathing! We got good preliminary evidence indicating that a large fraction of the air that they breathe in is literally wasted as it does not help in taking oxygen and eliminating carbon dioxide. What we still don't know is whether this wasted air goes to areas of the lungs that have been destroyed by the disease (called emphysema) or, alternatively, the problem is an insufficient amount of blood going to areas that still receive a good amount of air. To solve this puzzle, we will use, for the first time, a cutting-edge technique based on magnetic resonance imaging (MRI) coupled with a CAT scan to precisely quantify the flow of air and blood in lung regions with and without emphysema. If we prove that part of their wasted ventilation is caused by too much air relative to blood in lung regions without emphysema, our study will open a new perspective to use the proper medications to treat the right persons: drugs to increase blood flow through the lungs (called pulmonary vasodilators) to decrease the wasted air thereby improving their shortness of breath.