TY - JOUR
T1 - Assessment of the peripheral ventilatory response to CO2 in heart failure patients
T2 - Reliability of the single-breath test
AU - Maestri, Roberto
AU - Bruschi, Claudio
AU - Olmetti, Francesca
AU - La Rovere, Maria Teresa
AU - Pinna, Gian Domenico
PY - 2013/9
Y1 - 2013/9
N2 - The assessment of chemoreflex sensitivity in heart failure patients is gaining increasing interest since recent studies demonstrated that augmented chemosensitivity is an independent predictor of mortality and represents an important pathogenic factor in the development of Cheyne-Stokes respiration. The single-breath CO2 test is a well-established method to quantify peripheral hypercapnic chemoreflex sensitivity. As the original criteria for the computation of the chemoreflex sensitivity in healthy subjects need to be modified in heart failure patients to take into account impaired cardiac function, the effects of such modifications on measurement reliability deserve investigation. Hence, we devised this study to assess the reliability of the single-breath CO2 test in heart failure patients. In 27 clinically stable, mild-to-moderate heart failure patients (age (mean±SD): 64±10 years, left ventricular ejection fraction: 34±7%, NYHA class: 2.7±0.4), the test was administered on two consecutive days in the same conditions. Reliability was assessed by the standard error of measurement (SEM) and by the intraclass correlation coefficient (ICC). The mean value of the chemoreflex sensitivity on the two days was: 0.25 ± 0.12 and 0.24 ± 0.12 l min-1 mmHg-1 (p = 0.45), respectively. The SEM was 0.05 l min-1 mmHg-1, indicating large intra-subject variability. Consequently, in order to be 95% confident that a real change has occurred between two measurements taken on the same individual (test-retest), the observed difference must be higher than ±0.15 l min-1 mmHg-1, which is about 60% of the mean value across our population. The ICC was 0.71, indicating thatintra-subject variability, although high, is a limited (29%) portion of inter-subject variability. Intra-subject variability should be carefully taken into account when using the single-breath CO2 test in assessing changes in individual patients. The observed ICC indicates that this test may provide useful information for diagnostic/classification purposes.
AB - The assessment of chemoreflex sensitivity in heart failure patients is gaining increasing interest since recent studies demonstrated that augmented chemosensitivity is an independent predictor of mortality and represents an important pathogenic factor in the development of Cheyne-Stokes respiration. The single-breath CO2 test is a well-established method to quantify peripheral hypercapnic chemoreflex sensitivity. As the original criteria for the computation of the chemoreflex sensitivity in healthy subjects need to be modified in heart failure patients to take into account impaired cardiac function, the effects of such modifications on measurement reliability deserve investigation. Hence, we devised this study to assess the reliability of the single-breath CO2 test in heart failure patients. In 27 clinically stable, mild-to-moderate heart failure patients (age (mean±SD): 64±10 years, left ventricular ejection fraction: 34±7%, NYHA class: 2.7±0.4), the test was administered on two consecutive days in the same conditions. Reliability was assessed by the standard error of measurement (SEM) and by the intraclass correlation coefficient (ICC). The mean value of the chemoreflex sensitivity on the two days was: 0.25 ± 0.12 and 0.24 ± 0.12 l min-1 mmHg-1 (p = 0.45), respectively. The SEM was 0.05 l min-1 mmHg-1, indicating large intra-subject variability. Consequently, in order to be 95% confident that a real change has occurred between two measurements taken on the same individual (test-retest), the observed difference must be higher than ±0.15 l min-1 mmHg-1, which is about 60% of the mean value across our population. The ICC was 0.71, indicating thatintra-subject variability, although high, is a limited (29%) portion of inter-subject variability. Intra-subject variability should be carefully taken into account when using the single-breath CO2 test in assessing changes in individual patients. The observed ICC indicates that this test may provide useful information for diagnostic/classification purposes.
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U2 - 10.1088/0967-3334/34/9/1123
DO - 10.1088/0967-3334/34/9/1123
M3 - Article
C2 - 23969511
AN - SCOPUS:84883161018
VL - 34
SP - 1123
EP - 1132
JO - Physiological Measurement
JF - Physiological Measurement
SN - 0967-3334
IS - 9
ER -