The association between forced expiratory volume in one second (FEV1) and pulse oximetric measurements of arterial oxygen saturation (SpO2) in the patients with COPD: A preliminary study

BACKGROUND: The study was aimed to explore the association between arterial oxygen saturation (SpO2) and spirometer parameters of disease severity in chronic obstructive pulmonary disease (COPD) patients with a view to identify whether the pulse oximetry can be used as an alternative to arterial values in the clinical management of COPD patients in a routine practice. MATERIALS AND METHODS: Thirty-one patients with COPD were included in this study. After evaluation of each patient through history taking, physical examination and chest X-ray, SpO2 % and data regarding spirometry (FEV1% predicted and FEV1/FVC % predicted) in all patients were measured. Linear correlations among the variables were analyzed using the regression analysis. RESULTS: In total 31 COPD patients according to the criteria established by the Global Initiative for Chronic Obstructive Disease (GOLD) were included in the study. There was not statistically significant correlation between FEV1 % predicted and SpO2 values (P > 0.05), but a great correlation existed between FEV1/FVC % predicted and SpO2 values (r = 0.556, P < 0.001). Median SpO2 values did not differ between GOLD stages (Kruskal-Wallis test: P = 0.17). CONCLUSION: The study may demonstrate that oxygen saturation measured by pulse oximetry appears to be independent of the degree of airways obstruction as quantified by the FEV1; although further evidence needs to be assessed these preliminary findings.