mixed venous oxygen saturation
The oxygen saturation of blood returning to the heart, measured in the pulmonary artery as an indicator of tissue oxygen extraction.
Full Definition
Mixed venous oxygen saturation (SvO2) is a hemodynamic parameter that reflects the balance between oxygen delivery and consumption throughout the body. This measurement is obtained from blood drawn from the pulmonary artery via a Swan-Ganz catheter, representing the mixing of venous blood from all body tissues. Normal SvO2 values range from 65-75%, with lower values indicating either decreased oxygen delivery (due to low cardiac output, anemia, or hypoxemia) or increased oxygen consumption (fever, agitation, shivering). In cardiac surgery, continuous SvO2 monitoring helps assess the adequacy of tissue perfusion and guides management decisions regarding cardiac output optimization, fluid administration, and inotropic support.
Usage
Usage note: SvO2 is the standard abbreviation; distinguish from central venous saturation (ScvO2).
In Context
- "The mixed venous oxygen saturation remained above 70% throughout the procedure, indicating adequate tissue perfusion." — anesthesia record
- "A declining mixed venous oxygen saturation prompted optimization of cardiac output with inotropic agents." — ICU progress note