Approximate normal DO2 value?

Approximate normal DO2 value?

• A. 800 mL/min
• B. 1000 mL/min
• C. 2000 mL/min
• D. 150 mL/min

Answer: (B)

Oxygen delivery (DO2) is how much oxygen is carried to the tissues each minute. It depends on two things: how much blood the heart pumps (cardiac output) and how much oxygen that blood can carry (arterial oxygen content). The relationship is DO2 = CO × CaO2. Under normal resting conditions, CaO2 is about 20 mL O2 per 100 mL of blood (with Hb around 15 g/dL and SaO2 near 97%). If cardiac output is roughly 5 L/min, DO2 is about 5 L/min × 20 mL O2/100 mL = 1000 mL/min. So the approximate normal DO2 value is around 1000 mL/min. Values like 800 mL/min would imply a lower CO or CaO2, 150 mL/min is far too low for normal physiology, and 2000 mL/min would require a higher CO or CaO2 than typical at rest.

Oxygen delivery (DO2) is how much oxygen is carried to the tissues each minute. It depends on two things: how much blood the heart pumps (cardiac output) and how much oxygen that blood can carry (arterial oxygen content). The relationship is DO2 = CO × CaO2. Under normal resting conditions, CaO2 is about 20 mL O2 per 100 mL of blood (with Hb around 15 g/dL and SaO2 near 97%). If cardiac output is roughly 5 L/min, DO2 is about 5 L/min × 20 mL O2/100 mL = 1000 mL/min. So the approximate normal DO2 value is around 1000 mL/min. Values like 800 mL/min would imply a lower CO or CaO2, 150 mL/min is far too low for normal physiology, and 2000 mL/min would require a higher CO or CaO2 than typical at rest.