Application of a new parameter in the 6-minute walk test for manifold analysis of exercise capacity in patients with COPD

Journal Article

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International journal of chronic obstructive pulmonary disease

Int.J.Chron.Obstruct Pulmon Dis.

3-Nov

1235

1240

LR: 20151119; JID: 101273481; 0 (Biomarkers); S88TT14065 (Oxygen); OID: NLM: PMC4224096; OTO: NOTNLM; 2014 [ecollection]; 2014/11/03 [epublish]; epublish

New Zealand

1178-2005; 1176-9106

PMID: 25395845

eng

Journal Article; IM

10.2147/COPD.S71383 [doi]

Unknown(0)

25395845

BACKGROUND: New parameters in the 6-minute walk test (6 MWT) are required for comprehensive analysis of exercise capacity in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to apply a novel index, the desaturation distance ratio (DDR), to clinical research on COPD as an estimate of exercise capacity and to examine whether DDR is a potential parameter for manifold analysis of exercise capacity in patients with COPD. METHODS: A total of 41 patients with COPD (median age [interquartile range] =75 [68-79] years; and body mass index [BMI] =22.3 [19.4-23.8] kg/m(2)) participated in the study. The 6 MWT was performed along with anthropometric measurements and a pulmonary function test. The "desaturation area" was measured as the total area above the curve created using peripheral oxygen saturation (SpO2) values observed at each minute during the 6 MWT. Then the DDR was calculated as the ratio of the desaturation area to the 6-minute walk distance (6 MWD). RESULTS: The 6 MWD was 370 (328-445) m, and the decline in SpO2 values (DeltaSpO2) was -5.0% (-8.0% to -1.5%). The DDR correlated modestly with baseline pulmonary function in patients with COPD (forced expiratory volume in 1 second [% of predicted value]: r=-0.658, P0.001; and diffusing capacity of the lung for carbon monoxide [DL(CO)]: r=-0.470, P=0.002), comparable with the findings of the 6 MWD. The DDR correlated well with DeltaSpO2 (r=-0.656, P0.001) and with the increase in subjective sense of dyspnea during the 6 MWT, as assessed by Borg scale scores (DeltaBorg) (r=0.486, P=0.001), in contrast with the 6 MWD, which was not significantly correlated with DeltaSpO2 and DeltaBorg scale scores. CONCLUSION: The DDR is more informative for manifold analysis of exercise capacity associated with oxygen desaturation and subsequent sense of dyspnea by exercise in patients with COPD.

Ijiri,N., Kanazawa,H., Yoshikawa,T., Hirata,K.

Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan.; Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, Osaka, Japan.; Department of Sports Medicine, Graduate School of

20141103

PMC4224096

http://vp9py7xf3h.search.serialssolutions.com/?charset=utf-8&pmid=25395845

2014