Progressive Care Nursing Certification (PCCN) Practice Exam

An adult patient with status asthmaticus has ABGs indicating a worsening condition. Which ABG result most indicates this?

1. pH 7.50, pCO2 24, pO2 64, HCO3 23

2. pH 7.34, pCO2 47, pO2 59, HCO3 21

3. pH 7.44, pCO2 27, pO2 72, HCO3 25

4. pH 7.43, pCO2 39, pO2 69, HCO3 24

The correct answer is: pH 7.34, pCO2 47, pO2 59, HCO3 21

The selected answer reflects a significant acid-base disturbance consistent with worsening respiratory failure in a patient with status asthmaticus. In this scenario, the most notable ABG result is a pH of 7.34, which indicates acidemia. This level falls below the normal range of 7.35 to 7.45, emphasizing that the patient is in a state of acidosis, likely due to inadequate ventilation. The pCO2 value of 47 is also elevated, indicating that the patient is retaining carbon dioxide, which is indicative of respiratory acidosis. The normal range for pCO2 is generally between 35 and 45 mmHg. In status asthmaticus, the increased pCO2 levels and concurrent acidosis suggest that the patient is not effectively expiring CO2, which can occur due to bronchoconstriction and airway obstruction. Additionally, the low pO2 of 59 illustrates significant hypoxemia, which is common in severe asthma exacerbations where air exchange is compromised. In summary, this ABG result illustrates a picture of respiratory acidosis and hypoxemia, which are critical indicators of a worsening status in a patient with status asthmaticus, confirming the severity of the clinical condition.