Aim: To investigate whether the measurement of arterial oxygen saturation (SpO(2)) with pulse oximetry can identify those patients for whom spirometric screening for COPD would be useful, and those patients for whom spirometric assessment would not be useful.
Methods: Two hundred and ten patients, aged over 40, without significant dyspnoea, referred by their primary care physicians to the outpatient pulmonary clinic. The value of SpO(2) was recorded with a finger clip pulse oximeter sensor. Diagnostic values were obtained in order to diagnose COPD (defined as an FEV(1)/FVC ratio <0.70), and in order to detect patients with an FEV(1) <80% of predicted value.
Results: With SpO(2) <98%, sensitivity for detecting COPD was 79% and specificity 37%. Similar values were obtained for detecting patients with FEV(1) <80%. When only patients with FEV(1) <50% were considered, using a value of <98% for SpO2, sensitivity was 77%.
Conclusion: Pulse oximetry is not a useful test for selecting patients for screening spirometry in order to diagnose COPD.