Progressive Care Nursing Certification (PCCN) Practice Exam

A patient presents with symptoms of agitation and tingling fingers. An ABG reveals a pH of 7.49 and PaCO2 of 25. What is the correct interpretation?

1. Normal acid-base balance

2. Compensated respiratory alkalosis

3. Uncompensated respiratory alkalosis

4. Uncompensated metabolic alkalosis

The correct answer is: Uncompensated respiratory alkalosis

The correct interpretation is that the patient is experiencing uncompensated respiratory alkalosis. In this scenario, the arterial blood gas (ABG) results show a pH of 7.49, which indicates alkalosis since normal blood pH ranges from approximately 7.35 to 7.45. The PaCO2 value of 25 mmHg is significantly low, confirming that respiratory factors are contributing to the alkalosis, as a decreased PaCO2 leads to an increase in blood pH. Uncompensated respiratory alkalosis indicates that the primary disturbance is respiratory in nature, with no metabolic compensation occurring. If there were compensation, one would expect to see a change in the bicarbonate (HCO3-) level, typically an increase if the body was trying to compensate for the low PaCO2 by retaining acid. However, without any noticeable change in bicarbonate levels, the condition remains uncompensated. Understanding these values and their implications allows for the recognition of respiratory alkalosis, characterized by increased pH and decreased carbon dioxide levels. Thus, the interpretation that the patient is experiencing uncompensated respiratory alkalosis is accurate based on the provided ABG results.