title: Exercise performance and differences in physiological response to pulmonary rehabilitation in severe chronic obstructive pulmonary disease with hyperinflation.
abstract: OBJECTIVE
  Pulmonary rehabilitation (PR) improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation.
  
  
  METHODS
  We evaluated 22 COPD patients (age, 66 ± 7 years; FEV1 = 37.1 ± 11.8% of predicted) who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography) and determined maximal workloads.
  
  
  RESULTS
  We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001) and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02). At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO2), and minute ventilation. The inspiratory (operating) rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO2 during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue.
  
  
  CONCLUSIONS
  In severe COPD, PR appears to improve oxygen consumption and reduce VCO2, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.
authors.affiliation: Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: André Luis Pereira de
authors.initials: AL
authors.lastname: Albuquerque
authors.affiliation: Politecnico di Milano, Milano, Italia.
authors.forename: Marco
authors.initials: M
authors.lastname: Quaranta
authors.affiliation: Aintree University Hospital, Liverpool, United Kingdom.
authors.forename: Biswajit
authors.initials: B
authors.lastname: Chakrabarti
authors.affiliation: Politecnico di Milano, Milano, Italia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Aliverti
authors.affiliation: Aintree University Hospital, Liverpool, United Kingdom.
authors.forename: Peter M
authors.initials: PM
authors.lastname: Calverley
mesh_terms: D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000534:rehabilitation*; D012016:Reference Values; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013647:Task Performance and Analysis; D035441:Thoracic Wall / Q000503:physiopathology; D013997:Time Factors; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology
chemical_list: D002245:Carbon Dioxide