RT Journal Article
SR Electronic
T1 Dynamic oxyhemoglobin saturation changes during Walking and cycling tests in COPD
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P2504
VO 42
IS Suppl 57
A1 Ming-Lung Chuang
A1 I.-Feng Lin
YR 2013
UL http://erj.ersjournals.com/content/42/Suppl_57/P2504.abstract
AB Background: Resaturation of oxyhemoglobin saturation (SpO2) measured with pulse oximetry during exercise has not been addressed. We investigated the patterns and change in SpO2 (ΔSpO2) in six-minute walking test (6MWT) and cycling test in COPD patients.Methods: Sixty COPD patients with FEV1 54±18%pred estimated the oxygen-cost diagram (OCD) score and performed lung function test and 6MWT. Fifty patients performed cycling test. The patterns of ΔSpO2 were compared within individual tests and between both tests.Results: In the 6MWT, four patterns of SpO2 changed: mostly, desaturation-resaturation (46%). The ΔSpO2≥3% occurred at 1.23 minute. It resaturated at 3.5±1.4 minutes. The ΔSpO2 between the start and the nadir (ΔSpO2SN) was greater than that between the start and the end (ΔSpO2SE) (p<.0001). The non-desaturationers contained better inspiratory muscle strength, and less dyspnea and longer distance during the 6MWT than the others while the resaturationers had greater FEV1/FVC and smaller FRC than the other desaturationers (all p<.05).In the cycling test, three patterns of saturation changed: mostly, desaturation (58%). The ΔSpO2≥3% occurred at 68% of the cycling duration. The non-desaturationers had better body mass index, OCD score, lung function, work of walking, and peak exercise performance (all p<.05).In both tests, the ΔSpO2SN during the 6MWT was greater (p<.05) but the ΔSpO2SE was similar (p=.79). The non-desaturationers contained greater OCD scores (p<.01).Conclusions: Taking ΔSpO2SN rather than taking ΔSpO2SE during 6MWT is advocated. Exertional desaturation is related to demographics, lung function, and exercise performance. The OCD scores forecast desaturation in both tests.