Exercise-induced oxygen desaturation in COPD patients without resting hypoxemia

•Exercise-induced oxygen desaturation (EID) occurs frequently during the six-minute walk test (6MWT) in patients with Chronic Obstructive Pulmonary Disease (COPD)•We aimed to validate a proposed cut-off of baseline SpO2 ≤95% in pulse oximetry as simple screening procedure to predict EID during 6MWT.•We studied the prevalence and characteristics of patients exhibited EID to SpO2nadir ≤88%.•Baseline oxygen saturation solely is inaccurate to predict EID.•DLCO <50%, FEV1 <45%, PaO2 <10 kPa, baseline SpO2 <95%, and female sex were the strongest determinants of EID.

Exercise-induced oxygen desaturation (EID) is associated with increased risk of mortality in chronic obstructive pulmonary disease (COPD). Several screening tests have been proposed to predict EID, including FEV1, DLCO and baseline-SpO2. We aimed to validate a proposed cut-off of baseline-SpO2 ≤95% as simple screening procedure to predict EID during six-minute walk test (6MWT). In addition, we studied the prevalence and characteristics of patients exhibited EID to SpO2nadir ≤88%.402 non-hypoxemic COPD patients performed 6MWT. Sensitivity and specificity of baseline SpO2 ≤95% as a cut-off to predict EID and determinants of EID were investigated.158 patients (39%) exhibited EID. The sensitivity of baseline-SpO2 ≤95% to predict EID was 81.0%, specificity 49.2%, positive and negative predictive values were 50.8% and 80.0%, respectively. In a multivariate model, DLCO <50%, FEV1 <45%, PaO2 <10 kPa, baseline-SpO2 <95%, and female sex were the strongest determinants of EID.Baseline oxygen saturation solely is inaccurate to predict EID. A combination of clinical characteristics (DLCO, FEV1, PaO2, baseline-SpO2, sex) increases the odds for EID in COPD.

Graphical abstractA combination of certain lung function and baseline oxygen saturation characteristics revealed that the highest proportion of patients (95%) who exhibited exercise-induced oxygen desaturation (nadir-SpO2 ≤88%) are characterized by DLco <50% predicted and FEV1 <45% predicted with resting values of PaO2 <10 kPa and SpO2 <95%.Figure optionsDownload full-size imageDownload as PowerPoint slide