Relationship Between Multiple Physiologic Variables and Change in Exercise Capacity After a Pulmonary Rehabilitation Program

Abstract

Exercise capacity was evaluated before and after a 6-week pulmonary rehabilitation program in 49 patients with chronic obstructive lung disease (FEV1 = 1.65 ±.63 L), and preprogram predictors of functional improvement were determined by examining multiple baseline variables. The change in maximal oxygen consumption between the two tests (JOURNAL/jcrh/04.02/00008483-198808000-00004/ENTITY_OV0312/v/2017-08-08T011828Z/r/image-pngO2 Emax) was used as an index of change in exercise capacity. PaCO2 during exercise was found to correlate best with JOURNAL/jcrh/04.02/00008483-198808000-00004/ENTITY_OV0312/v/2017-08-08T011828Z/r/image-pngO2 Emax (r =.38). However, when patients with limiting exertional oxygen desaturation were both studied and trained with supplemental low flow oxygen, most were able to exercise to a higher level after rehabilitation. Of the other variables, respiratory exchange ratio at rest (r =.35), mean pulmonary artery pressure at rest (r = -.33) and maximum minute ventilation (r =.33) had the highest correlations. None of these values was statistically significant by multiple regression analysis. Stepwise multiple linear regression analysis determined that these variables accounted for 32% of the variance in JOURNAL/jcrh/04.02/00008483-198808000-00004/ENTITY_OV0312/v/2017-08-08T011828Z/r/image-pngO2 Emax. These results suggest that the degree of physiologic dysfunction before rehabilitation correlates poorly with change in exercise capacity after rehabilitation. Therefore, patients should not be excluded from participation in a pulmonary rehabilitation program based solely on initially poor physiologic values.