What is the normal arterial range for PaCO2?

What is the normal arterial range for PaCO2?

• A. 35-45 mm Hg
• B. 25-35 mm Hg
• C. 22-30 mm Hg
• D. 30-40 mm Hg

Answer: (A)

PaCO2 shows how effectively the lungs are removing carbon dioxide, reflecting ventilation. In a healthy adult, the normal arterial PaCO2 is about 35–45 mm Hg. This range represents the balance between CO2 production in the body and its elimination by the lungs. If ventilation increases, PaCO2 drops below normal; if ventilation decreases, PaCO2 rises above normal. This value helps interpret acid-base status and distinguish respiratory from metabolic disturbances. The other ranges listed are too low to be normal for an adult, indicating hypocapnia from over-ventilation rather than normal ventilation.

PaCO2 shows how effectively the lungs are removing carbon dioxide, reflecting ventilation. In a healthy adult, the normal arterial PaCO2 is about 35–45 mm Hg. This range represents the balance between CO2 production in the body and its elimination by the lungs. If ventilation increases, PaCO2 drops below normal; if ventilation decreases, PaCO2 rises above normal. This value helps interpret acid-base status and distinguish respiratory from metabolic disturbances. The other ranges listed are too low to be normal for an adult, indicating hypocapnia from over-ventilation rather than normal ventilation.