Which value is a typical alveolar PO2?

Which value is a typical alveolar PO2?

• A. 90
• B. 88
• C. 70
• D. 104

Answer: (D)

Alveolar PO2 reflects the oxygen tension in the air sacs where gas exchange occurs, and under normal room-air breathing at sea level it hovers around 100 mmHg. This value is close to arterial PO2 because oxygen diffuses into the blood, keeping PaO2 near the same range. Among the options, 104 mmHg best matches this typical alveolar level, while 90 or 88 would be lower than expected for alveolar gas in normal conditions, and 70 is too low. So 104 is the best choice.

Alveolar PO2 reflects the oxygen tension in the air sacs where gas exchange occurs, and under normal room-air breathing at sea level it hovers around 100 mmHg. This value is close to arterial PO2 because oxygen diffuses into the blood, keeping PaO2 near the same range. Among the options, 104 mmHg best matches this typical alveolar level, while 90 or 88 would be lower than expected for alveolar gas in normal conditions, and 70 is too low. So 104 is the best choice.