Progressive Care Nursing Certification (PCCN) Practice Exam

Given the arterial blood gas values of pH 7.55 and CO2 28, how should this condition be interpreted?

1. Respiratory acidosis

2. Compensated metabolic alkalosis

3. Non-compensated respiratory alkalosis

4. Metabolic alkalosis

The correct answer is: Non-compensated respiratory alkalosis

The interpretation of the arterial blood gas values reveals a pH of 7.55, indicating alkalosis, as a normal pH range is typically from 7.35 to 7.45. The CO2 level of 28 mmHg is lower than the normal range (which is about 35-45 mmHg), suggesting a respiratory component as carbon dioxide is an acidic component of the blood. When CO2 is low, it indicates that the body is effectively removing CO2, leading to respiratory alkalosis. In this context, when interpreting the results, an elevated pH alongside a low CO2 demonstrates that there has been an inappropriate increase in ventilation or removal of carbon dioxide. The situation leads to a state of respiratory alkalosis. The consideration of "non-compensated" indicates that there isn't another process occurring that would be correcting the alkalosis, such as a metabolic acid-base disorder. Compensated states would typically show a pH that approaches normal due to the body's physiological adjustments. The other options correspond to conditions characterized by different pH and CO2 relationships, indicating that they don't align with the given values of pH 7.55 and CO2 28 mmHg, which firmly places the interpretation in the realm