@article {473226,
	title = {Lung deflation and oxygen pulse in COPD: results from the NETT randomized trial.},
	journal = {Respiratory medicineRespiratory medicine},
	volume = {106},
	year = {2012},
	month = {Feb},
	pages = {109-119},
	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\<0.0001 and 0.47 mL/beat, p\<0.0001, respectively) corresponded with significant reductions in HR and improvements in VO(2). On multivariate analysis, deflators were 88\% more likely than non-deflators to have an improvement in O(2) pulse (OR 1.88, 95\% CI 1.30-2.72, p=0.0008).CONCLUSION:In COPD, decreased hyperinflation through lung volume reduction is associated with improved O(2) pulse.},
	author = {Come, Carolyn E and Divo, Miguel J and San Jose 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 and NETT Research Group}
}