(see also SVO2 Monitoring; Swan-Ganz Pulmonary Artery Catheter)
ScVO2 monitoring, like SVO2 monitoring, assesses tissue perfusion status and enables early detection of clinical response to interventions. While SVO2 measurement requires a pulmonary artery (PA) catheter, ScVO2 measurement is done by placing a fiber-optic central venous catheter into the superior vena cava (for continuous monitoring) or a simple catheter where values can be obtained through intermittent sampling (venous gas). Continuous ScVO2 monitoring permits early observation of changes in global oxygenation parameters and is routinely inserted in patients for monitoring of CVP and administration of inotropes/vasopressors and TPN. Because the blood measured by ScVO2 has not yet been diluted with blood from the coronary sinus, the value typically runs 7% higher than SVO2 in critically ill patients (normal ScVO2, 70%; normal SVO2, 60% to 80%). However, while both SVO2 and ScVO2 values differ slightly, they will both trend the same. ScVO2 is of particular value in treating septic shock and is a component of the 6-hour sepsis bundle. In the context of lactate > 4 mmol/L or SBP < 90 mm Hg despite 20 mL/kg fluid, the CVP should be maintained at >8 mm Hg and ScVO2> 70%.