Abstract
INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) who have nocturnal oxygen desaturation (NOD) should be treated with nocturnal oxygen therapy (NOT) for avoiding morbidity and mortality. Nocturnal oximetry is an expensive and time consuming test that used for evaluating NOD individuals.
AIM: To evaluate whether desaturation during 6-minute walk test (6MWT) is useful for predicting NOD in COPD.
METHODS: Stable moderate or severe COPD patients were enrolled in this study. Spirometry and carbon monoxide diffusion test (DLCO), arterial blood gas analysis, 6MWT and nocturnal oximetry were performed. Patients with obstructive sleep apnea, hypoxemic respiratory failure, and who were receiving noninvasive mechanical ventilation therapy were excluded.
RESULTS: Totally 61 patients (55 male, age: 65.8±8.4) were analysed. Thirty of them had moderate and the others (n=31) had severe COPD. Forced expiratory volume 1 second was 1352±348ml (51.2%±11.8%). Patients who were desaturated during 6MWT had significantly lower DLCO, PaO2, SaO2 and higher PaCO2 levels than the patients who did not desaturated (p<0.001, p=0.001, p=0.001, p=0.02). NOD was more common in severe COPD patients or the patients with higher CO2 levels (p=0.02, p=0.001). Four patients (13%) with moderate COPD were desaturated during 6MWT, however they did not have NOD. Five (33%) of severe COPD patients who were desaturated during 6MWT(n=15) also had NOD. Moderate correspondence was found between 6MWT and NOD in severe COPD patients (Kappa=0.39, p<0.05).
CONCLUSION: 6MWT can be recommended as a simple, cheap tool for predicting NOD and selecting individuals for NOT particularly in severe COPD.
- © 2013 ERS
