If SvO2 is 30-50%, what does this indicate?

If SvO2 is 30-50%, what does this indicate?

• A. Normal extraction
• B. Exhausted extraction; beginning of lactic acidosis
• C. Compensatory extraction
• D. Severe lactic acidosis

Answer: (B)

SvO2 shows the balance between oxygen delivery to the tissues and how much oxygen the tissues are using. When delivery meets demand, SvO2 stays in a normal range. If delivery falls or demand rises, tissues extract more oxygen, and SvO2 drops. A mixed venous saturation in the 30–50% range means extraction is exhausted—the tissues have pulled out as much O2 as they can, and delivery is still not enough for the demand. At this point, anaerobic metabolism begins, producing lactate, so you’re just at the start of lactic acidosis. In short, low SvO2 indicates inadequate oxygen delivery relative to consumption, with the early onset of metabolic stress driven by oxygen shortfall.

SvO2 shows the balance between oxygen delivery to the tissues and how much oxygen the tissues are using. When delivery meets demand, SvO2 stays in a normal range. If delivery falls or demand rises, tissues extract more oxygen, and SvO2 drops. A mixed venous saturation in the 30–50% range means extraction is exhausted—the tissues have pulled out as much O2 as they can, and delivery is still not enough for the demand. At this point, anaerobic metabolism begins, producing lactate, so you’re just at the start of lactic acidosis. In short, low SvO2 indicates inadequate oxygen delivery relative to consumption, with the early onset of metabolic stress driven by oxygen shortfall.