Certified Transport Registered Nurse Certification Practice Exam

A P/F ratio of 200-300 indicates which condition?

1. Severe ARDS

2. Mild ARDS

3. Moderate ARDS

4. Normal lung function

The correct answer is: Mild ARDS

A P/F ratio, which is the ratio of arterial oxygen partial pressure (PaO2) to the fraction of inspired oxygen (FiO2), is a critical parameter used to assess the severity of acute respiratory distress syndrome (ARDS). In the context of ARDS classification, a P/F ratio of 200-300 indicates mild ARDS. Mild ARDS is characterized by impaired gas exchange but not to the extent seen in moderate or severe cases. When the P/F ratio falls within this range, it suggests that there is some level of hypoxemia present, but the patient does not have critical failure—reflecting the ability of the lungs to maintain relatively good oxygenation compared to more severe levels of ARDS where the P/F ratio drops significantly lower. Understanding the classification and the P/F ratio is essential for guiding treatment and management strategies for patients suffering from ARDS, ensuring that appropriate clinical interventions can be applied based on the severity of the condition.