BACKGROUND:Patients with congestive heart failure or COPD may share an increased response in minute ventilation (V E ) to carbon dioxide output (V CO 2 ) during exercise. The goal of this study was to ascertain whether the V E /V CO 2 slope and V E /V CO 2 intercept can discriminate between subjects with congestive heart failure and those with COPD at equal peak oxygen uptake (V O 2 ). 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 V E /V CO 2 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 V O 2 < 16 mL/kg/min, but not > 16 mL/kg/min (28.3 ؎ 5.3 vs 28.9 ؎ 6.6). The V E /V CO 2 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 V O 2 < 16 mL/kg/min were considered, subjects with COPD had a higher likelihood to have the V E /V CO 2 intercept > 2.14 L/min (0.92 sensitivity, 0.96 specificity). Regardless of peak V O 2 , the end-tidal pressure of CO 2 (P ETCO 2 ) 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 P ETCO 2 . CONCLUSIONS: The ventilatory response to V CO 2 during exercise was significantly different between subjects with congestive heart failure and those with COPD in terms of the V E /V CO 2 slope with moderate-to-severe reduction in exercise capacity and in terms of the V E /V CO 2 intercept regardless of exercise capacity.
BackgroundPulmonary hyperinflation has the potential for significant adverse effects on cardiovascular function in COPD. The aim of this study was to investigate the relationship between dynamic hyperinflation and cardiovascular response to maximal exercise in COPD patients.MethodsWe studied 48 patients (16F; age 68 yrs ± 8; BMI 26 ± 4) with COPD. All patients performed spirometry, plethysmography, lung diffusion capacity for carbon monoxide (TLco) measurement, and symptom-limited cardiopulmonary exercise test (CPET). The end-expiratory lung volume (EELV) was evaluated during the CPET. Cardiovascular response was assessed by change during exercise in oxygen pulse (ΔO2Pulse) and double product, i.e. the product of systolic blood pressure and heart rate (DP reserve), and by the oxygen uptake efficiency slope (OUES), i.e. the relation between oxygen uptake and ventilation.ResultsPatients with a peak exercise EELV (%TLC) ≥ 75% had a significantly lower resting FEV1/VC, FEF50/FIF50 ratio and IC/TLC ratio, when compared to patients with a peak exercise EELV (%TLC) < 75%. Dynamic hyperinflation was strictly associated to a poor cardiovascular response to exercise: EELV (%TLC) showed a negative correlation with ΔO2Pulse (r = - 0.476, p = 0.001), OUES (r = - 0.452, p = 0.001) and DP reserve (r = - 0.425, p = 0.004). Furthermore, according to the ROC curve method, ΔO2Pulse and DP reserve cut-off points which maximized sensitivity and specificity, with respect to a EELV (% TLC) value ≥ 75% as a threshold value, were ≤ 5.5 mL/bpm (0.640 sensitivity and 0.696 specificity) and ≤ 10,000 Hg · bpm (0.720 sensitivity and 0.783 specificity), respectively.ConclusionThe present study shows that COPD patients with dynamic hyperinflation have a poor cardiovascular response to exercise. This finding supports the view that in COPD patients, dynamic hyperinflation may affect exercise performance not only by affecting ventilation, but also cardiac function.
Interstitial lung diseases (ILDs) are functionally characterized by a restrictive ventilatory defect due to a reduced distensibility of the lung parenchyma. ILD patients also show a reduced exercise tolerance, the main factors limiting exercise capacity being ventilatory and gas exchange abnormalities. Functional abnormalities in ILDs are typical, but not specific. Despite the fact that different lung function patterns have been described among ILDs, they overlap and their practical application to differentiate ILDs is poor. Resting pulmonary function and exercise-induced hypoxemia can aid in defining the prognosis of ILDs and in referring patients for lung transplantation. Additionally, spirometry and diffusing capacity are useful to monitor the response of patients to therapy.
FeNO measurements obtained by the new portable FeNO analyzer are reliable because they are directly comparable with those obtained by the stationary standard device. The use of portable instruments may facilitate the FeNO measurement in primary care.
Small airways are relevant to the pathophysiology of asthma. We investigated whether in asthmatic patients with normal forced expiratory volume in the 1st second (FEV(1)) values, impulse oscillometry system (IOS), as a measure of small airway function, contributed additional information to spirometry either at baseline or after bronchodilator, and whether it was related to the disease control. The fall in resistance from 5 to 20 Hz (R5-R20) and reactance at 5 Hz (X5) by IOS and spirometry measures of small airway function (forced expiratory flow at 25-75% [FEF(25-75)] and forced vital capacity/slow inspiratory vital capacity [FVC/SVC]) at baseline and after 400 micrograms of salbutamol were prospectively measured in 33 asthmatic patients (18 women; age range, 18-66 years). Disease control was assessed by the Asthma Control Test (ACT). R5-R20 but not X5 values were significantly related to FEF(25-75) and FVC/SVC values (p < 0.05 for both correlations). When the bronchodilator response was assessed, no correlation was found among IOS and spirometry changes. ACT scores were related to R5-R20, FEF(25-75), and FVC/SVC values (p < 0.01 for all correlations). In asthmatic patients with normal FEV(1) values, R5-R20 values were related to spirometry measures of small airway function. However, when the bronchodilator response was assessed, IOS and spirometry provided quite different results. Moreover, small airway dysfunction, as assessed by IOS and spirometry, was associated with poor disease control and history of asthma exacerbations. The results of this study confirm the value of IOS, as an investigative tool, and suggest that in asthmatic patients with normal FEV(1) values and poor disease control, small airway function should be investigated.
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