TY - JOUR T1 - Critical Velocity Determined by a Non-Exhaustive Method in Subjects With COPD JF - Respiratory Care DO - 10.4187/respcare.05637 SP - respcare.05637 AU - Marceli Rocha Leite AU - Juliana Souza Uzeloto AU - Bruna Spolador de Alencar Silva AU - Ana Paula Coelho Figueira Freire AU - Fabiano Francisco de Lima AU - Eduardo Zapaterra Campos AU - Diego Giulliano Destro Christofaro AU - Carlos Augusto Kalva-Filho AU - Dionei Ramos AU - Ercy Mara Cipulo Ramos Y1 - 2017/12/05 UR - http://rc.rcjournal.com/content/early/2017/12/05/respcare.05637.abstract N2 - BACKGROUND: Exercise training is an effective and low-cost tool for COPD rehabilitation. Thus, validating a non-exhaustive method to determine a patient's anaerobic threshold would be a very interesting tool in practical settings. We aimed to test the reproducibility of critical velocity values determined in a non-exhaustive manner (CVNE) and tolerance for exercise performed at this physiological marker in subjects with COPD. METHODS: Twelve subjects with COPD were evaluated in this cross-sectional study. The study was divided into 2 phases: Phase A consisted of reproducibility of CVNE for subjects with COPD, and Phase B determined the tolerance for exercise tests performed at this physiological marker.RESULTS: The proposed protocol for determining CVNE presented fair reproducibility according to blood lactate concentrations (intraclass correlation coefficient = 0.58). However, we cannot consider that the tests were reproducible due to the wide CI (0.03–0.85). Furthermore, moderate and strong correlations were observed between the CVNE determined by lactate concentration, by oxygen consumption (V̇O2) (r = 0.66), and by heart rate (r = 0.88). However, a high limit of agreement was observed ±1.45 km/h and ±1.55 km/h, respectively. In the tolerance for exercise test, none of the subjects presented lactate destabilization, whereas 3 tests were interrupted by oxygen saturation decline and 1 test was interrupted by hemodynamic instability.CONCLUSIONS: Although most of the subjects presented good tolerance for exercise at CVNE, fair levels of reproducibility were observed in subjects with COPD, even using lactate. Thus, the use of CVNE determined through double 3-min efforts should be considered with caution. ER -