Clinical outcomes of expiratory muscle training in severe COPD patients

SummaryThe most common symptoms in chronic obstructive pulmonary disease (COPD) patients are breathlessness and exercise limitation. Although both general and inspiratory muscle training have shown clinical benefits, the effects of specific expiratory muscle training remain controversial.ObjectiveTo investigate the effects of expiratory training on lung function, exercise tolerance, symptoms and health-related quality of life in severe COPD patients.MethodsSixteen patients (FEV1, 28±8% pred.) were randomised to either expiratory muscle or sham training groups, both completing a 5-week programme (30 min sessions breathing through an expiratory threshold valve 3 times per week) (50% of their maximal expiratory pressure (MEP) vs. placebo, respectively). Lung function, exercise capacity (bicycle ergometry and walking test), and clinical outcomes (dyspnoea and quality of life (St. George Respiratory Questionnaire (SGRQ)) were evaluated both at baseline and following the training period.ResultsAlthough lung function remained roughly unchanged after training, exercise capacity, symptoms and quality of life significantly improved. The improvement in both walking distance and the SGRQ score significantly correlated with changes in MEP.ConclusionOur results confirm that a short outpatient programme of expiratory training can improve symptoms and quality of life in severe COPD patients. These effects could be partially explained by changes in expiratory muscle strength.