Arterial oxygen content (CaO2) is measured in which units?

Arterial oxygen content (CaO2) is measured in which units?

• A. mL O2/dL or Vol%
• B. mg/dL
• C. L/dL
• D. μmol/L

Answer: (A)

CaO2 represents how much oxygen is carried by arterial blood per unit volume, so the units are milliliters of O2 per deciliter of blood, commonly written as mL O2/dL. It can also be expressed as a volume percent, because 1 vol% equals 1 mL O2 per 100 mL of blood. This reflects the oxygen content per blood volume, not a mass or molar quantity. Other units like mg/dL, L/dL, or μmol/L don’t directly describe oxygen content per blood volume, so they aren’t appropriate for CaO2.

CaO2 represents how much oxygen is carried by arterial blood per unit volume, so the units are milliliters of O2 per deciliter of blood, commonly written as mL O2/dL. It can also be expressed as a volume percent, because 1 vol% equals 1 mL O2 per 100 mL of blood. This reflects the oxygen content per blood volume, not a mass or molar quantity. Other units like mg/dL, L/dL, or μmol/L don’t directly describe oxygen content per blood volume, so they aren’t appropriate for CaO2.