SESSION TITLE: ILD
SESSION TYPE: Slide Presentations
PRESENTED ON: Saturday, March 22, 2014 at 12:15 PM - 01:15 PM
PURPOSE: The relationship between maximal cardiopulmonary exercise testing (CPX) and submaximal exercise in patients with idiopathic pulmonary fibrosis (IPF) is poorly understood. CPX and the 6-minute walk test (6MWT) were compared with a focus on exercise tolerance (ET) and systemic oxidant stress (OS) in patients with IPF.
METHODS: Eighteen patients with IPF underwent maximal cycle ergometry CPX and the 6MWT. Blood samples were obtained for 15-F2t-isoprostanes (IP) before and immediately after CPX. CPX and 6MWT dependent variables were cycling duration (CD) and 6MWT distance (6MWTD), respectively. Correlation and multivariate linear regression (MVLR) analyses were performed.
RESULTS: Significant correlations (p<0.05) among CPX measures and CD included peak oxygen consumption (O2) and carbon dioxide (CO2) production as well as resting and peak end-tidal oxygen (PETO2) and carbon dioxide (PETCO2) with the greatest correlation between resting PETO2 and CD (r=0.76). Significant correlations (p<0.05) among CPX measures and 6MWTD included resting PETO2, peak respiratory rate, and peak IP with the greatest correlation between peak IP and 6MWTD (r=0.83). The DLCO, resting PET O2, and VE/VCO2 slope were significantly correlated to both submaximal and maximal ET. The VE/VCO2 slope was significantly correlated to DLCO, resting and peak PETO2 and PETCO2, and several measures of ventilatory efficiency. MVLR found none of the independent variables to be significant predictors of CD. Peak Borg RPE was found to be a significant (p=0.04) predictor and peak IP a nearly significant (p=0.07) predictor of 6MWTD.
CONCLUSIONS: In MVLR models CPX measures explain very little of maximal and submaximal exercise tolerance in patients with IPF. Further examination of submaximal and maximal exercise in patients with IPF is needed.
CLINICAL IMPLICATIONS: The significant relationship of the VE/VCO2 slope to many physiologic and functional measures is important and deserving of further examination in patients with IPF. The significant correlation of systemic OS to submaximal exercise tolerance and nearly significant role in a multivariate model also warrants further examination. Finally, the effect of maximal exercise on plasma IP suggests that the administration of supplemental oxygen to patients with IPF is in need of further attention and investigation.
DISCLOSURE: The following authors have nothing to disclose: Lawrence Cahalin, Carol Ramos, Ignacio Gaunaurd, Nicole Eustis, Constanza Sol, Meryl Cohen, Orlando Gomez-Marin, Diana Cardenas, Robert Jackson
No Product/Research Disclosure Information