Diaphragmatic Mobility and Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is characterized by progressive obstruction of the airways which is partially irreversible. COPD patients commonly present increased resistance to airflow, air trapping, and pulmonary hyperinflation that alters the chest wall placing the respiratory muscles in mechanical disadvantage, thereby increasing both respiratory drive and the sensation of dyspnoea. Furthermore, to prevent dyspnoea, COPD patients reduce their daily living activities leading to loss of physical condition, social isolation, depression and anxiety,whilst compromising their quality of life. Forced expiratory volume in one second (FEV1) is the main parameter used to establish the severity of pulmonary impairment and disease progression. Nevertheless, some studies have suggested that FEV1 does not adequately reflect the clinical manifestations of the disease and is only weakly associated with the severity of dyspnoea, health related quality of life (HRQOL) features, and the ability to perform activities of daily living. Moreover, FEV1 appears not to be a predictor of mortality in COPD patients. Pulmonary hyperinflation has been related with adaptation in diaphragm muscle maintaining the muscle's capacity to generate power whilst reducing its displacement. The importance of the diaphragm in lung mechanics associated with hyperinflation has been the subject of frequent discussion owing to widespread use of lung volume reducing surgery which results in increased movement range of the diaphragm muscle. However, to date, the relationship between diaphragm mobility and functional capacity in COPD patients remains unknown. The objective of the present study was to evaluate the influence of diaphragm mobility in the exercise capacity and dyspnoea of patients with COPD.