ABSTRACT
Dyspnea is the major symptom for most patients with chronic respiratory diseases. In this chapter, the authors review available data on the longitudinal changes in dyspnea ratings in both clinical trials and observational studies, analyze the relationships among changes in dyspnea and the changes in other clinical measurements, and discuss appropriate instruments for assessing longitudinal changes in dyspnea. They describe findings primarily in patients with chronic obstructive pulmonary disease (COPD)because most investigations have been performed in longitudinal population. Thus, progressive dyspnea in patients with COPD may be related not only to progressive airflow limitation but also to worsening of diffusing capacity, exercise capacity, and psychological status. Longitudinal changes in dyspnea are an important measurement in patients with cardiorespiratory diseases, as dyspnea can be a principal symptom in these conditions. Dyspnea can longitudinally worsen even while lung function remains stable, and vice versa.
