Hypoxemia is defined as what?

• A. Increased oxygen in the blood
• B. Normal oxygenation
• C. Reduced oxygen in the blood
• D. Fluctuating oxygen saturation

Answer: (C)

Hypoxemia means there is not enough oxygen in the arterial blood. Clinically, it’s shown as a lower-than-normal PaO2 (the oxygen tension in arterial blood) or reduced oxygen saturation (SaO2). This is why the correct choice is “reduced oxygen in the blood.” The other descriptions don’t fit: increased oxygen in the blood would be hyperoxemia, normal oxygenation isn’t hypoxemia, and fluctuating oxygen saturation describes variability rather than a consistently low oxygen level.