Progressive Care Nursing Certification (PCCN) Practice Exam

ABG results for a patient with COPD show pH 7.24, pCO2 78, pO2 54, and HCO3 30. What does this indicate?

1. Acute respiratory acidosis

2. Compensated metabolic acidosis

3. Compensated respiratory alkalosis

4. Acute metabolic alkalosis

The correct answer is: Acute respiratory acidosis

The arterial blood gas (ABG) results show a pH of 7.24, indicating acidosis since a normal pH range is approximately 7.35 to 7.45. The pCO2 level is 78 mmHg, which is significantly elevated above the normal range of 35-45 mmHg, suggesting that the patient is retaining CO2, typically seen in respiratory disorders like COPD. The pO2 of 54 mmHg indicates hypoxemia, which is common in COPD patients due to compromised lung function. The bicarbonate (HCO3) level is 30 mEq/L, which is higher than normal (22-26 mEq/L) and indicates a compensatory mechanism. In the case of respiratory acidosis, the kidneys often retain bicarbonate to help counteract the increase in acidity caused by excess CO2 retention. However, the key indicators in this scenario are the low pH and significantly high pCO2, which confirm that the primary issue is acute respiratory acidosis. This simplifies the interpretation: the low pH signifies an acidosis state, the high pCO2 confirms it as primarily respiratory in nature, and the elevated HCO3 suggests some compensation has begun, but it does