From the Research
Hyperoxemia in Venous Blood Gas
Hyperoxemia in a venous blood gas indicates an elevated level of oxygen in the venous blood. This can be seen in the following points:
- The mixed venous and central venous oxygen saturations reflect the balance between oxygen requirement and oxygen delivery, and thus may be used to assess the adequacy of tissue oxygenation 1.
- The oxygen saturation of the haemoglobin of mixed venous blood (SvO(2)) reflects the peripheral extraction of oxygen (O(2)), O(2) delivery and consumption 2.
- Central venous blood gas (VBG) parameters of pH and Pco2 are potentially good surrogates for determining arterial pH and Pco2 in a stable patient without severe acid-base disturbances 3.
- The correlation of VBG analysis plus pulse oximetry (SpO2) with ABG analysis can provide accurate information on acid-base, ventilation, and oxygenation status for undifferentiated critically ill patients 4.
Key Points to Consider
- Hyperoxemia in venous blood gas may indicate that the patient is receiving too much supplemental oxygen, or that there is an issue with the patient's oxygen delivery or consumption.
- The measurement of mixed venous oxygen saturation can help determine whether cardiac output and oxygen delivery are sufficient for metabolic needs 5.
- The speed of blood withdrawal does not affect the accuracy of mixed venous oxygen saturation measurements 5.
- Central venous saturation may have prognostic significance following major surgery, and further evaluation of peri-operative trends in central venous saturation is required 1.