Title: “Chronic Hyperinflation and Exertional Dyspnea in COPD Patients Pre- and Post-Lung Transplant”
Supervisor: Dr. Bill Sheel
Committee members: Dr. Don McKenzie, Dr. Robert Levy, Dr. Jordan Guenette
Abstract: In COPD patients, chronic hyperinflation due to abnormal gas exchange, emphysematous deterioration of lung tissue, and airflow limitation not only contribute to ventilatory impairments but also systemic physiological consequences of disease, primarily exertional dyspnea. Dyspnea is the subjective experience of breathing discomfort and is the most common and distressing symptom of COPD for patients at rest and especially during exercise. Pharmaceutical interventions consistently and successfully relieve dyspnea in those with COPD in the short-term. What is yet unclear is how best to mitigate the severity of breathlessness long-term. COPD lung transplant patients provide a model to further investigate the mechanisms of dyspnea as it relates to mechanical constraints and the absence thereof. In British Columbia this year, nearly all lung transplants performed will be double lung transplants. Single lung transplant patients may still be subjected to the poor function of the remaining diseased native lung. However, with double lung transplant patients for COPD, this surgical intervention provides an opportunity to address the question if dyspnea persists chronically in the absence of ventilatory and mechanical constraint.
The purpose of this proposed work is to compare ratings of dyspnea, the mechanics of breathing, and hyperinflation in COPD patients pre- and post-double lung transplantation during submaximal exercise. This study will evaluate changes in lung mechanics and chest wall mechanics due to hyperinflation using optoelectronic plethysmography (OEP). OEP is a non-invasive motion-capture analysis tool used to capture the motion and displacement of the chest wall and calculate relative changes in lung volume. It is hypothesized that while overall severity of dyspnea will improve post-transplant, those who still experience hyperinflation following transplant, either due to chronic abnormal structural changes pre-transplant or due to differences between donor and recipient organs, will experience more severe exertional dyspnea post-operatively.