title: Ventilatory efficiency before and after lung volume reduction surgery.
abstract: BACKGROUND
  Lung volume reduction surgery (LVRS) has been shown to improve the clearance of carbon dioxide and minute ventilation (V̇E) in select patients with COPD. One variable often assessed in COPD is ventilatory efficiency (V̇E/V̇CO2 ).
  
  
  METHODS
  We compared 55 LVRS subjects with 25 controls from the National Emphysema Treatment Trial. V̇E/V̇CO2 was calculated from cardiopulmonary exercise testing at baseline and 6-months. We sought to assess V̇E/V̇CO2 changes with LVRS compared with controls who only received standard medical care.
  
  
  RESULTS
  At 6 months, the LVRS group significantly increased peak V̇O2 , work load, V̇E, V̇CO2 , and tidal volume while lowering peak and lowest V̇E/V̇CO2 (improved ventilatory efficiency) and end-tidal carbon dioxide pressure. The control group did not display these changes. The changes were greatest in the LVRS subjects who improved their exercise capacity after surgery (> 10 W).
  
  
  CONCLUSIONS
  The changes were greatest in the LVRS subjects who showed the most functional improvement, indicating an association of improved ventilation with improved functional outcome.
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York hfa2104@columbia.edu.
authors.forename: Hilary F
authors.initials: HF
authors.lastname: Armstrong
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York.
authors.forename: Nicole E
authors.initials: NE
authors.lastname: Dussault
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York Department of Rehabilitation Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wilawan
authors.initials: W
authors.lastname: Thirapatarapong
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York.
authors.forename: Renee S
authors.initials: RS
authors.lastname: Lemieux
authors.affiliation: Department of Medicine: Pulmonary, Allergy and Critical Care, Columbia University Medical Center, New York, New York.
authors.forename: Byron M
authors.initials: BM
authors.lastname: Thomashow
authors.affiliation: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, New York Department of Rehabilitation Medicine, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York.
authors.forename: Matthew N
authors.initials: MN
authors.lastname: Bartels
mesh_terms: D000368:Aged; D002245:Carbon Dioxide; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology; D011013:Pneumonectomy; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology* / Q000601:surgery*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012115:Residual Volume; D012189:Retrospective Studies; D013990:Tidal Volume; D014797:Vital Capacity
chemical_list: D002245:Carbon Dioxide
keywords: chronic obstructive pulmonary disease; exercise; gas exchange