Cardiopulmonary exercise testing in patients with chronic obstructive pulmonary disease.

Severe chronic obstructive pulmonary disease is characterized by limited exercise capacity as a result of changes in pulmonary mechanics, abnormal gas exchange, altered cardiac function, respiratory muscle dysfunction, nutritional factors, and dyspnea. Cardiopulmonary exercise testing is a safe, effective method for objectively studying exercise performance and may be carried out using simple walk tests or more complicated treadmill or cycle-ergometry testing. Indications in patients with chronic obstructive pulmonary disease include defining the etiology of dyspnea, evaluating work disability or impairment, and assessing the response to therapy or the need for supplemental oxygen. It is also indicated in preoperative evaluation and as part of a pulmonary rehabilitation program.