Chest wall volume regulation during exercise in COPD patients with GOLD stages II to IV

The present study investigated how end-expiratory ribcage and abdominal volume regulation during exercise is related to the degree of dynamic chest wall hyperinflation in patients with different spirometric severity of chronic obstructive pulmonary disease (COPD) based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. In total, 42 COPD patients and 11 age-matched healthy subjects were studied during a ramp-incremental cycling test to the limit of tolerance (W(peak)). Volume variations of the chest wall (at end expiration (EEV(cw)) and end inspiration) and its compartments (ribcage (V(rc)) and abdominal (V(ab))) were computed by optoelectronic plethysmography. At W(peak), only patients in GOLD stages III and IV exhibited a significant increase in EEV(cw) (increase of 454+/-509 and 562+/-363 mL, respectively). These patients did not significantly reduce end-expiratory V(ab), whereas patients in GOLD stage II resembled healthy subjects with significantly reduced end-expiratory V(ab) (decrease of 287+/-350 mL). In patients, the greater the increase in EEV(cw) at W(peak), the smaller the reductions in end-expiratory V(ab) and the greater the increase in end-expiratory V(rc). In chronic obstructive pulmonary disease patients with different spirometric disease severity, greater degrees of exercise-induced dynamic chest wall hyperinflation were accompanied by lower degrees of end-expiratory abdominal volume displacement and larger increases in end-expiratory ribcage volume.