title: Effective Bronchoscopic Lung Volume Reduction Accelerates Exercise Oxygen Uptake Kinetics in Emphysema.
abstract: BACKGROUND
  The impact of bronchoscopic lung volume reduction (BLVR) on physiologic responses to exercise in patients with advanced emphysema remains incompletely understood. We hypothesized that effective BLVR (e-BLVR), defined as a reduction in residual volume > 350 mL, would improve cardiovascular responses to exercise and accelerate oxygen uptake (Vo₂) kinetics.
  
  
  METHODS
  Thirty-one patients (FEV1, 36% ± 9% predicted; residual volume, 219% ± 57% predicted) underwent a constant intensity exercise test at 70% peak work rate to the limit of tolerance before and after treatment bronchoscopy (n = 24) or sham bronchoscopy (n = 7). Physiologic responses in patients who had e-BLVR (n = 16) were compared with control subjects (ineffective BLVR or sham bronchoscopy; n = 15).
  
  
  RESULTS
  e-BLVR reduced residual volume (-1.1 ± 0.5 L, P = .001), improved lung diffusing capacity by 12% ± 13% (P = .001), and increased exercise tolerance by 181 ± 214 s (P = .004). Vo₂ kinetics were accelerated in the e-BLVR group but remained unchanged in control subjects (Δ mean response time, -20% ± 29% vs 1% ± 25%, P = .04). Acceleration of Vo₂ kinetics was associated with reductions in heart rate and oxygen pulse response half-times by 8% (84 ± 14 to 76 ± 15 s, P = .04) and 20% (49 ± 16 to 34 ± 16 s, P = .01), respectively. There were also increases in heart rate and oxygen pulse amplitudes during the cardiodynamic phase post e-BLVR. Faster Vo₂ kinetics in the e-BLVR group were significantly correlated with reductions in residual volume (r = 0.66, P = .005) and improvements in inspiratory reserve volume (r = 0.56, P = .024) and exercise tolerance (r = 0.63, P = .008).
  
  
  CONCLUSIONS
  Lung deflation induced by e-BLVR accelerated exercise Vo₂ kinetics in patients with emphysema. This beneficial effect appears to be related mechanistically to an enhanced cardiovascular response to exercise, which may contribute to improved functional capacity.
authors.affiliation: Faculty of Physical Education for Men, Alexandria University, Alexandria, Egypt.
authors.forename: Azmy
authors.initials: A
authors.lastname: Faisal
authors.affiliation: The NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, England; Respiratory and Critical Care Institute, Cleveland Clinic Abu Dhabi, United Arab Emirates.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Zoumot
authors.affiliation: The NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, England.
authors.forename: Pallav L
authors.initials: PL
authors.lastname: Shah
authors.affiliation: Department of Medicine, Queen's University, Kingston, ON, Canada.
authors.forename: J Alberto
authors.initials: JA
authors.lastname: Neder
authors.affiliation: The NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, England.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Polkey
authors.affiliation: The NIHR Respiratory Biomedical Research Unit at Royal Brompton and Harefield NHS Foundation Trust and Imperial College, London, England. Electronic address: n.hopkinson@ic.ac.uk.
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Hopkinson
mesh_terms: D001999:Bronchoscopy / Q000379:methods*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010991:Plethysmography; D011013:Pneumonectomy / Q000379:methods*; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000503:physiopathology / Q000601:surgery; D011656:Pulmonary Emphysema / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D012115:Residual Volume; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D010100:Oxygen
keywords: chronic obstructive pulmonary disease; exercise pulmonary; exercise testing