Cardiovascular adaptation in the six-minute walk test in COPD patients: transversal study

Abstract

OBJECTIVE: To evaluate the behavior of cardiovascular adaptation and peripheral oxygen saturation in individuals with COPD submitted to the six-minute walk test (6MWT). MATERIAL AND METHODS: It was performed a descriptive study with person with a diagnosis of COPD confirmed by spirometry of both sexes. The Medical Research Council (MRC) dyspnea scale and the COPD Assessment Test (CAT) questionnaire were used to assess the magnitude of symptoms. The 6MWT was used to assess effort tolerance. To measure the maximum heart rate (HRmax) predicted for age, specific equations were used for the Brazilian population. RESULTS: 34 individuals with COPD were evaluated, 20 (58.8%) men; FEV1 / FVC ratio was 56.7% ± 10.2% after BD. Fourteen (41.2%) were classified as grade 2 and were classified as grade 2 (MRC scale). The means of the distances covered in the first and second TC6 were 383.5 ± 13.6; 408.6 ± 85.7 meters, corresponding to 70.7%; 75.1% in relation to the predicted value (p = 0.001). The mean maximum heart rate at the end of the first and second 6MWT were 94.1 ± 21.9; 92.3 ± 17.9 bpm and the heart rate post-percentage of the predicted maximum heart rate before and after the 6MWT were 61.1% ± 17.7%; 59.7% ± 21.5% and 14 (41.2%) patients presented O 2 desaturation on the 6MWT; 9 (26.5%) in the second test. CONCLUSIONS: Patients with COPD throughout the 6MWT show increased heart rate and O2 desaturation in exercise activity.