Ventilatory response to carbon dioxide output in subjects with congestive heart failure and in patients with COPD with comparable exercise capacity.
Respir Care
; 59(7): 1034-41, 2014 Jul.
Article
in En
| MEDLINE
| ID: mdl-24046458
ABSTRACT
BACKGROUND:
Patients with congestive heart failure or COPD may share an increased response in minute ventilation (VÌE) to carbon dioxide output (VÌCO2 ) during exercise. The goal of this study was to ascertain whether the VÌE/VÌCO2 slope and VÌE/VÌCO2 intercept can discriminate between subjects with congestive heart failure and those with COPD at equal peak oxygen uptake (VÌO2 ).METHODS:
We studied 46 subjects with congestive heart failure (mean age 61 ± 9 y) and 46 subjects with COPD (mean age 64 ± 8 y) who performed a cardiopulmonary exercise test.RESULTS:
The VÌE/VÌCO2 slope was significantly higher in subjects with congestive heart failure compared with those with COPD (39.5 ± 9.5 vs 31.8 ± 7.4, P < .01) at peak VÌO2 < 16 mL/kg/min, but not ≥ 16 mL/kg/min (28.3 ± 5.3 vs 28.9 ± 6.6). The VÌE/VÌCO2 intercept was significantly higher in both subgroups of subjects with COPD compared with the corresponding values in the subjects with congestive heart failure (3.60 ± 1.7 vs -0.16 ± 1.7 L/min, P < .01; 3.63 ± 2.7 vs 0.87 ± 1.5 L/min, P < .01). According to receiver operating characteristic curve analysis, when all subjects with peak VÌO2 < 16 mL/kg/min were considered, subjects with COPD had a higher likelihood to have the VÌE/VÌCO2 intercept > 2.14 L/min (0.92 sensitivity, 0.96 specificity). Regardless of peak VÌO2 , the end-tidal pressure of CO2 (PETCO2 ) at peak exercise was not different in subjects with congestive heart failure (P = .42) and was significantly higher in subjects with COPD (P < .01) compared with the corresponding unloaded PETCO2 .CONCLUSIONS:
The ventilatory response to VÌCO2 during exercise was significantly different between subjects with congestive heart failure and those with COPD in terms of the VÌE/VÌCO2 slope with moderate-to-severe reduction in exercise capacity and in terms of the VÌE/VÌCO2 intercept regardless of exercise capacity.Key words
Full text:
1
Database:
MEDLINE
Main subject:
Oxygen Consumption
/
Pulmonary Gas Exchange
/
Pulmonary Disease, Chronic Obstructive
/
Heart Failure
Type of study:
Diagnostic_studies
/
Etiology_studies
/
Incidence_studies
/
Observational_studies
/
Risk_factors_studies
Limits:
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Language:
En
Year:
2014
Type:
Article