Effects of rehabilitation on chest wall volume regulation during exercise in COPD patients

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
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; and Dept of Physical Education and Sport Science, Athens, Greece
³ Dipartimento di Bioingegneria, Politecnico di Milano, Milano, Italy

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

	Abstract

To investigate underlying mechanisms, we studied the effect of pulmonary rehabilitation on the regulation of total chest wall and compartmental (rib cage, abdominal) volumes during exercise in patients with chronic obstructive pulmonary disease.

Twenty patients (FEV₁:39±3% predicted) undertook high intensity exercise 3 days·week^-1 for 12 weeks. Before and after rehabilitation changes in chest wall volumes at the end of expiration (EEVcw) and inspiration (EIVcw) were computed by opto-electronic plethysmography during incremental exercise to the limit of tolerance (Wpeak).

Rehabilitation significantly (p<0.05) improved Wpeak [(mean±SEM) 57±7 versus 47±5 watt]. Post-rehabilitation at an identical work rate there were significant reductions in minute ventilation (35.1±2.7 versus 38.4±2.7 l·min^-1), breathing frequency (26±1 versus 29±1 breaths·min^-1), as well as in EEVcw (by 182±79 ml) and EIVcw (by 136±37 ml); inspiratory reserve volume was also significantly increased (by 148±70 ml). Volume reductions were attributed to significant changes in end-expiratory and end-inspiratory abdominal volumes (by 163±59 and 125±27 ml, respectively). The improvement in Wpeak was similar in patients who progressively hyperinflated during exercise and those who did not (by 24 and 26%, respectively).

Pulmonary rehabilitation lowers chest wall volumes during exercise by decreasing the abdominal volumes. The improvement in exercise capacity following rehabilitation is independent of the pattern of exercise-induced dynamic hyperinflation.

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