USES

• measurement of oxygenation saturation from mixed venous blood (SvO2) in the pulmonary artery
• requires Pulmonary Artery Catheter insertion in most clinical settings

DESCRIPTION

• measures the end result of O2 consumption and delivery

METHOD OF INSERTION AND/OR USE

O2 flux = (cardiac output x (Hemoglobin concentration x SpO2 x 1.34) + (PaO2 x 0.003)) – oxygen consumption

• SvO2 = mixed venous oxygen saturation
• measured via a sample of blood from a pulmonary artery catheter (PAC)
• measures the end result of O2 consumption and delivery
• is used in ICU as a measure of O2 extraction by the body
• normal SvO2 = 65-70%
• SvO2 > ScvO2 as it contains blood from both SVC and IVC
• if SvO2 low then either consumption elevated or demand high
• 0.5 corresponds to a theoretical critical PvO2 of 26mmHg -> level where tissue dysoxia is highly likely
• > 0.8 corresponds with high flow states: sepsis, hyperthyroidism, severe liver disease