@article {1433740,
	title = {Lung deflation and oxygen pulse in COPD: results from the NETT randomized trial},
	journal = {Respir Med},
	volume = {106},
	number = {1},
	year = {2012},
	month = {2012 Jan},
	pages = {109-19},
	abstract = {BACKGROUND: In COPD patients, hyperinflation impairs cardiac function. We examined whether lung deflation improves oxygen pulse, a surrogate marker of stroke volume.

METHODS: In 129 NETT patients with cardiopulmonary exercise testing (CPET) and arterial blood gases (ABG substudy), hyperinflation was assessed with residual volume to total lung capacity ratio (RV/TLC), and cardiac function with oxygen pulse (O(2) pulse=VO(2)/HR) at baseline and 6 months. Medical and surgical patients were divided into "deflators" and "non-deflators" based on change in RV/TLC from baseline (∆RV/TLC). We defined deflation as the ∆RV/TLC experienced by 75\% of surgical patients. We examined changes in O(2) pulse at peak and similar (iso-work) exercise. Findings were validated in 718 patients who underwent CPET without ABGs.

RESULTS: In the ABG substudy, surgical and medical deflators improved their RV/TLC and peak O(2) pulse (median ∆RV/TLC -18.0\% vs. -9.3\%, p=0.0003; median ∆O(2) pulse 13.6\% vs. 1.8\%, p=0.12). Surgical deflators also improved iso-work O(2) pulse (0.53 mL/beat, p=0.04 at 20 W). In the validation cohort, surgical deflators experienced a greater improvement in peak O(2) pulse than medical deflators (mean 18.9\% vs. 1.1\%). In surgical deflators improvements in O(2) pulse at rest and during unloaded pedaling (0.32 mL/beat, p,
	keywords = {Aged, Blood Gas Analysis, Cohort Studies, Exercise Test, Female, Forced Expiratory Volume, Humans, Lung, Male, Middle Aged, Multivariate Analysis, Oxygen Consumption, Pneumonectomy, Pulmonary Disease, Chronic Obstructive, Stroke Volume, Total Lung Capacity},
	issn = {1532-3064},
	doi = {10.1016/j.rmed.2011.07.012},
	author = {Come, Carolyn E and Divo, Miguel J and San Jos{\'e} Est{\'e}par, Ra{\'u}l and Sciurba, Frank C and Criner, Gerard J and Marchetti, Nathaniel and Scharf, Steven M and Mosenifar, Zab and Make, Barry J and Keller, Cesar A and Minai, Omar A and Martinez, Fernando J and Han, MeiLan K and Reilly, John J and Celli, Bartolome R and Washko, George R}
}