TY - JOUR
T1 - A symptom-limited incremental step test determines maximum physiological responses in patients with chronic obstructive pulmonary disease
AU - Dal Corso, Simone
AU - De Camargo, Anderson Alves
AU - Izbicki, Meyer
AU - Malaguti, Carla
AU - Nery, Luiz Eduardo
N1 - Funding Information:
Funded by a research grant from São Paulo Research Foundation (FAPESP – Processo 2010/09732-6 ). AAC received a master fellowship grant from PROSUP/CAPES . CM is a Postdoctoral Fellow at Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo (UNIFESP). LEN and SDC are Established Investigators of the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).
PY - 2013/12
Y1 - 2013/12
N2 - Background Step tests have been used to evaluate exercise tolerance and effort-related hypoxemia in different diseases. A symptom-limited incremental step test (IST) has never been tested in COPD patients. Aim To compare maximal physiological responses between an IST and cardiopulmonary exercise testing (CPET), to test the reproducibility of the IST on different days, and to provide a predict equation to estimate VO2 from the IST in patients with COPD. Material and methods At the same day, thirty-four patients (VEF 1 46 ± 14% of pred) underwent a CPET on cycle ergometer and the first IST (IST-1) (1 h apart). After 2-5 days, patients repeated the IST (IST-2). Pulmonary gas exchange was measured during all tests. Results Peak VO2 was significantly higher in IST-1 and IST-2 than in CEPT (Mean ± SD: 1.19 ± 0.39 L, 1.20 ± 0.40 L, 1.07 ± 0.35 L) with no difference for ventilation (VE), heart rate (HR), and perception of effort. ISTs were highly reproducible, with significant intraclass correlation coefficient (CCI [95% confidence interval]) for number of steps (0.98[0.95-0.99]), VO2 (0.99 [0.98-0.99]), VE (0.97[0.93-0.99]), HR (0.92[0.81-0.97]), and SpO2 (0.96[0.90-0.98]). Desaturation was significantly higher for IST-1 and IST-2 compared with cycling (Mean ± SD: -6 ± 5%, -6 ± 4%, -3 ± 3%). Number of steps and patient weight explained 81% of the variance in peak VO2 (p < 0.001). Conclusion A symptom-limited incremental step test, externally paced, elicits maximal cardiopulmonary and metabolic responses, and is well tolerated and reproducible in patients with COPD.
AB - Background Step tests have been used to evaluate exercise tolerance and effort-related hypoxemia in different diseases. A symptom-limited incremental step test (IST) has never been tested in COPD patients. Aim To compare maximal physiological responses between an IST and cardiopulmonary exercise testing (CPET), to test the reproducibility of the IST on different days, and to provide a predict equation to estimate VO2 from the IST in patients with COPD. Material and methods At the same day, thirty-four patients (VEF 1 46 ± 14% of pred) underwent a CPET on cycle ergometer and the first IST (IST-1) (1 h apart). After 2-5 days, patients repeated the IST (IST-2). Pulmonary gas exchange was measured during all tests. Results Peak VO2 was significantly higher in IST-1 and IST-2 than in CEPT (Mean ± SD: 1.19 ± 0.39 L, 1.20 ± 0.40 L, 1.07 ± 0.35 L) with no difference for ventilation (VE), heart rate (HR), and perception of effort. ISTs were highly reproducible, with significant intraclass correlation coefficient (CCI [95% confidence interval]) for number of steps (0.98[0.95-0.99]), VO2 (0.99 [0.98-0.99]), VE (0.97[0.93-0.99]), HR (0.92[0.81-0.97]), and SpO2 (0.96[0.90-0.98]). Desaturation was significantly higher for IST-1 and IST-2 compared with cycling (Mean ± SD: -6 ± 5%, -6 ± 4%, -3 ± 3%). Number of steps and patient weight explained 81% of the variance in peak VO2 (p < 0.001). Conclusion A symptom-limited incremental step test, externally paced, elicits maximal cardiopulmonary and metabolic responses, and is well tolerated and reproducible in patients with COPD.
KW - Cardiopulmonary exercise test
KW - COPD
KW - Exercise tolerance
KW - Field test
KW - Oxygen uptake
KW - Step test
UR - http://www.scopus.com/inward/record.url?scp=84890309240&partnerID=8YFLogxK
U2 - 10.1016/j.rmed.2013.06.013
DO - 10.1016/j.rmed.2013.06.013
M3 - Article
C2 - 23863809
AN - SCOPUS:84890309240
SN - 0954-6111
VL - 107
SP - 1993
EP - 1999
JO - Respiratory Medicine
JF - Respiratory Medicine
IS - 12
ER -