Certified Pediatric Nurse (CPN)

Which acid-base imbalance is present in the following ABG: pH = 7.47, CO2 = 41, HCO3 = 28?

1. Respiratory acidosis

2. Metabolic acidosis

3. Respiratory alkalosis

4. Metabolic alkalosis

The correct answer is: Metabolic alkalosis

The pH value of 7.47 indicates that the blood is alkalotic, as normal arterial blood pH ranges from approximately 7.35 to 7.45. When the pH exceeds this range, the condition may be classified as alkalosis. In this case, the bicarbonate (HCO3) level is measured at 28 mEq/L, which is within the normal range of about 22 to 26 mEq/L, but it is slightly elevated. The carbon dioxide (CO2) level is at 41 mmHg, which is also within the normal range of about 35 to 45 mmHg. The elevation in pH combined with normal CO2 and slightly increased HCO3 suggests an alkalosis condition that is likely metabolic. In metabolic alkalosis, bicarbonate levels tend to increase, often due to factors such as excessive vomiting, diuretic use, or other metabolic conditions that lead to a rise in alkalinity. This combination of pH being elevated with HCO3 slightly above normal and CO2 remaining stable leads to the conclusion that metabolic alkalosis is present. Therefore, the analysis points to metabolic alkalosis as the accurate diagnosis from the available data.