Validity of Peripheral Capillary Oxygen Saturation and Normal Mixed Venous Oxygen Tension in Measurement of O2 Content


1 Pediatric Pulmonologist, Pediatric Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.

2 Fellowship of Pediatric Pulmonology, Pediatric Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.


The change in venous oxygen saturation occurs earlier, and even its reduction is faster than arterial oxygen saturation. The aim of this study was to validate SvO2 and PvO2 for O2 content measurement in children hospitalized with respiratory distress.
Materials and Methods
In this cross-sectional study, 80 children who were admitted with respiratory distress were included in the study according to the study inclusion and exclusion criteria. Baseline characteristics such as age and gender were recorded in the data collection form, designed by the researcher. In order to determine the amount of SaO2 and PaO2 the arterial blood sample was prepared, venous blood sample was prepared to determine the amount of hemoglobin, SvO2 and PvO2. The gold standard for the determination of O2 content was the arterial blood sample. All samples were examined by a blood gas analyzer and then calculated using the formula of O2 content values. For SvO2 and PvO2 validation, we used diagnostic analysis methods including sensitivity, specificity, positive and negative predictive values. Cut-point value for SvO2 and PvO2 were 76.50 and 44.30, respectively.
In this study, the patients’ mean age was 5.15 ± 4.20 years. 62.5% (n=50) were male and 38.5% (n=30) were female. The values ​​of arterial and venous O2 content were 14.13 ± 3.05 and 11.95 ± 3.04 from a total of 80 patients. SvO2 and PvO2 for measuring O2 content had a sensitivity of 80.5 and 71.80%, respectively, and specificity of 80.5 and 78%, respectively.
SvO2 and PvO2 have good validity for evaluating O2 content in patients admitted to PICU. So that SvO2 had a sensitivity and specificity of over 80%, and PvO2 had a sensitivity and specificity of over 70%.