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

¹ National & Kapodistrian University of Athens, Dept of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, Pulmonary Rehabilitation Centre, "M. Simou and G.P. Livanos" Laboratories; and Dept of Physical Education and Sport Science, Athens, Greece
² National & Kapodistrian University of Athens, Dept of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, Pulmonary Rehabilitation Centre, "M. Simou and G.P. Livanos" Laboratories
³ World Wide Medical, Pfizer Inc. NY, USA

^* To whom correspondence should be addressed. E-mail: E-mail:gianvog{at}phed.uoa.gr.

	Abstract

The present study investigated how end-expiratory rib cage and abdominal volume regulation during exercise is related to the degree of dynamic chest wall hyperinflation in patients with different spirometric severity of COPD based on the GOLD classification.

Forty-two COPD patients and eleven healthy age-matched subjects were studied during a ramp-incremental cycling test to the limit of tolerance (Wpeak). Volume variations of the chest wall [at end-expiration (EEVcw) and end-inspiration] and its compartments [rib cage (Vrc) and abdominal (Vab)] were computed by Optoelectronic Plethysmography.

At Wpeak only patients in GOLD stages III and IV exhibited a significant increase in EEVcw (by 454±509 and 562±363 ml, respectively). These patients did not significantly reduce end-expiratory Vab, whereas patients in GOLD stage II resembled healthy subjects in that they significantly reduced end-expiratory Vab (by 287±350 ml). In patients, the greater the increase in EEVcw at Wpeak, the smaller were the reductions in end-expiratory Vab (r=0.76; p=0.0001) and the greater was the increase in end-expiratory Vrc (r=0.62; p=0.001).

In COPD patients with different spirometric disease severity, greater degrees of exercise-induced dynamic chest wall hyperinflation are accompanied by lower degrees of end-expiratory abdominal volume displacement and larger increases in end-expiratory rib cage volume.