Normal arterial pO2 range is:

• A. 60–80 mmHg
• B. 80–110 mmHg
• C. 90–120 mmHg
• D. 100–140 mmHg

Answer: (B)

PaO2 is the partial pressure of oxygen in arterial blood, indicating how well oxygen moves from the lungs into the blood. In a healthy adult breathing room air at sea level, the oxygen tension in arterial blood typically sits around 95–100 mmHg, and a normal reference range is commonly considered to be about 80–110 mmHg to accommodate individual variation and measurement differences. Values below 80 mmHg indicate hypoxemia, while values above about 110 mmHg are not usually seen as a normal resting value on room air.

Thus, the range that best matches a normal arterial pO2 is 80–110 mmHg.