Ventilatory efficiency before and after lung volume reduction surgery

Hilary F. Armstron, Nicole E. Dussault, Wilawan Thirapatarapong, Renee S. Lemieux, Byron M. Thomashow, Matthew N. Bartels

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Background: Lung volume reduction surgery (LVRS) has been shown to improve the clearance of carbon dioxide and minute ventilation (VE) in select patients with COPD. One variable often assessed in COPD is ventilatory efficiency (VE/VCO2). Methods: We compared 55 LVRS subjects with 25 controls from the National Emphysema Treatment Trial. VE/VCO2 was calculated from cardiopulmonary exercise testing at baseline and 6-months. We sought to assess VE/CO2changes with LVRS compared with controls who only received standard medical care. Results: At 6 months, the LVRS group significantly increased peak VO2, work load, VE, VCO2, and tidal volume while lowering peak and lowest VE/CO2(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.

Original languageEnglish (US)
Pages (from-to)63-71
Number of pages9
JournalRespiratory care
Issue number1
StatePublished - 2015


  • Chronic obstructive pulmonary disease
  • Exercise
  • Gas exchange

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine


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