Question

A male patient presents to the emergency department. The arterial blood gas report is as follows: pH, 7.2; pCO2, 81 mmHg; and HCO3, 40meq/L. which of the following is the most likely diagnosis?

• A. Respiratory alkalosis
• B. Metabolic acidosis
• C. Respiratory acidosis
• D. Metabolic alkalosis

Answer 1

The Correct Option is C

To solve the given problem, we must analyze the arterial blood gas (ABG) values to determine the most likely diagnosis. We are provided the following values:

• pH: 7.2
• pCO2: 81 mmHg
• HCO3^-: 40 meq/L

Let's evaluate these:

1. Normal physiological values: The normal pH range is 7.35 to 7.45. The normal pCO2 range is 35 to 45 mmHg. The normal HCO3^- range is 22 to 26 meq/L.
2. In this case, the pH is 7.2, which indicates acidosis (since it is below the normal range of 7.35-7.45).
3. The pCO2 is elevated at 81 mmHg, suggesting a retention of CO2, which is typical of respiratory acidosis.
4. The HCO3^- is elevated at 40 meq/L, suggesting renal compensation by increasing bicarbonate to attempt to normalize the pH.
5. Conclusion: The primary issue is an elevated pCO2, leading to an acidic pH, indicative of respiratory acidosis. This also matches the elevated HCO3^- value, indicating compensation. Hence, the most likely diagnosis is respiratory acidosis, making this the correct choice for the given arterial blood gas values.