Abstract
We hypothesized that abdominal binding (AB) would relieve dyspnea and improve exercise tolerance by enhancing neuromuscular efficiency of the diaphragm during exercise in COPD. In a randomized crossover study, 16 patients (9 men) aged 65.6±2.3 yrs with GOLD stage I-III COPD (FEV1= 64.4±5.1 %predicted) underwent symptom-limited constant load cycle exercise testing at 75% of their peak incremental work rate without (CTRL) and with AB sufficient to increase end-expiratory gastric pressures (Pga,ee) by 5-8 cmH2O at rest. Assessments of exercise endurance time (EET), dyspnea, ventilation (VE), breathing pattern (BP), operating lung volumes (OLVs), diaphragm EMG activity expressed as a percentage of maximum (EMGdi%max) and transdiaphragmatic pressure swings (Pdi,swing) were compared between AB and CTRL at rest and during exercise. Compared to CTRL, AB increased Pga,ee by 6.2±2.4 cmH2O and enhanced neuromuscular efficiency of the diaphragm during exercise (by ∼25%), as evidenced by increased Pdi,swing in the setting of an unchanged EMGdi%max. Nevertheless, AB had no effect on EET or on VE, BP, OLVs and/or dyspnea intensity ratings during exercise. In the absence of changes in VE, BP, OLVs and EMGdi%max, isolated and acute improvements in neuromuscular efficiency of the diaphragm during exercise with AB in COPD were not associated with dyspnea relief and improved exercise tolerance.
- Copyright ©ERS 2015
