PT  - JOURNAL ARTICLE
AU  - Hilary F Armstrong
AU  - Nicole E Dussault
AU  - Wilawan Thirapatarapong
AU  - Renee S Lemieux
AU  - Byron M Thomashow
AU  - Matthew N Bartels
TI  - Ventilatory Efficiency Before and After Lung Volume Reduction Surgery
AID  - 10.4187/respcare.03233
DP  - 2014 Nov 04
TA  - Respiratory Care
PG  - respcare.03233
4099  - http://rc.rcjournal.com/content/early/2014/11/04/respcare.03233.short
4100  - http://rc.rcjournal.com/content/early/2014/11/04/respcare.03233.full
AB  - 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.