Comparative analysis of the arterial oxygen saturation (SaO2) and pulse oximetry measurements (SpO2) in patients with pulmonary tuberculosis

Measurement the arterial oxygen saturation (SaO2) by pulse oximetry (SpO2), using a fingertip sensor is commonly used in the management of patients with pulmonary diseases. The aim of study was to compare SaO2 results obtained from earlobe and SpO2 results obtained from fingertip in patients with pulmonary tuberculosis (PT). Methods: In 150 patients with PT (84 male and 66 female; aged 47.7±16.1; FEV1 74.4±28.1 % predicted) the paired samples were compared. In addition to SaO2, other parameters (pH, PaCO2, PaO2) were analyzed in the samples obtained from the earlobe. The Bland and Altman method, regression, and ROC-analysis were used. Results: The mean difference between SaO2 (94.4±3.6%) and SpO2 (94.9±3.7%) was minus 0.6 percentage point (pp). Limits of agreement were 4.0 pp and -5.1 pp. The value of the difference depended on PaO2 (correlation coefficient (R) was minus 0.49; coefficient of determination (R2) was 0.22; p According ROC curve analysis to determine value of SpO2 for the difference between SaO2 and SpO2 more 3 pp, when We did not find the influence of age, FEV1, pH, PaCO2 on the value of the difference between SaO2 and SpO2. Conclusion: Oxygen saturation results determined of different ways are often not identical. The difference between SaO2 and SpO2 are often more 3 pp when SpO2 results obtained from fingertip less than 94%.