Certified Transport Registered Nurse Certification Practice Exam

What does a P/F ratio of 100-200 indicate?

1. Normal lung function

2. Mild ARDS

3. Moderate ARDS

4. Severe ARDS

The correct answer is: Moderate ARDS

A P/F ratio, which stands for the PaO2/FiO2 ratio, is a valuable indicator used to assess the degree of hypoxemia in patients, particularly in the context of acute respiratory distress syndrome (ARDS). This ratio is calculated by dividing the arterial oxygen partial pressure (PaO2) by the fractional inspired oxygen (FiO2). When the P/F ratio falls between 100 and 200, it indicates that the patient is experiencing moderate ARDS. This classification is crucial because it helps healthcare professionals determine the severity of respiratory failure and guides treatment decisions. Moderate ARDS involves a significant level of impairment in oxygenation, requiring closer monitoring and potentially more aggressive intervention than mild ARDS, which is characterized by a P/F ratio above 200. In contrast, a P/F ratio below 100 would denote severe ARDS, while a ratio above 200 but below 300 would indicate mild ARDS. Thus, the range of 100-200 specifically corresponds to moderate ARDS, validating the answer provided as being correct. Understanding these classifications helps transport nurses and other healthcare providers to implement appropriate management strategies for patients with respiratory failure.