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Background: The purpose of this study was to determine the correlation between SpO2 and arterial 02 saturation measured with blood gas analyzer (SaO2) in hypoxemic and non-hypoxemic patients. Hypoxemia was considered as SP02<90%.
Methods: In this study, Sp02 and SaO2 were measured simultaneously. Mean±SD of SpO2 and SaO2 with coefficient of correlation, accuracy, sensitivity and specificity were measured and calculated.
Results: This study included 152 patients. The accuracy of pulse oximetry was 90.8%, sensitivity was 93.3% and specificity was 89.1%. The hypoxemic and non-hypoxemic patients had good correlation between Sp02 and SaO2 (in hypoxemic group: r = 0.865, p<0.001; in non-hypoxemic group: r = 0.95, p<0.001). In 22 patients with SpO2 <80%, the mean±SD of SpO2 and SaO2 were 70.63±9.13% and 74.40+10.24%, respectively (p=0.003); in 44 patients with 90%>Sp02>80%, the mean ±SD of SpO2 and Sa02were 86.31 ±2.83% and 87.30±4.22% (p=0.105), respectively; and in 86 patients with Sp02>90%, the mean±SD of SpO2 and Sa02 were 94.37±2.18% and 94.17±3.71% (p=0.590), respectively.
Conclusions: In pulmonary diseases with Sp02 > 80%, pulse oximetry has high accuracy in estimating SaO2 and may be used instead of arterial blood gases (ABG). In patients with SpO2 < 80%, however, the exact estimation of SaO2 and the evaluation of oxygenation by pulse oximeter is not a good substitution for ABG analyzer.