What does a normal PaCO2 level indicate?

• A. No respiratory issue
• B. Respiratory acidosis
• C. Respiratory alkalosis
• D. Metabolic issue only

Answer: (A)

PaCO2 shows how well you’re ventilating; its normal range means the lungs aren’t driving an acid-base problem. So, when PaCO2 is normal, there isn’t a primary respiratory acidosis or alkalosis—that’s why the best choice is that there’s no respiratory issue.

But remember, you still have to check the other values, especially the pH and bicarbonate. A metabolic disturbance can exist even with a normal PaCO2, if the metabolic factor is the main driver or if partial compensation has occurred. If the pH is abnormal with a normal PaCO2, that points to a metabolic origin. If both pH and PaCO2 are normal, the overall acid-base status is normal.