FPGEE for National Association of Boards of Pharmacy (NABP) Practice Exam

At what partial pressure of oxygen is respiratory failure reported?

1. 40 mmHg

2. 50 mmHg

3. 60 mmHg

4. 70 mmHg

The correct answer is: 60 mmHg

Respiratory failure is characterized by an inadequate oxygenation of the blood, which can be assessed by measuring the partial pressure of oxygen (PaO2) in arterial blood. A PaO2 of 60 mmHg is generally considered the threshold for respiratory failure. Below this level, the body's ability to adequately oxygenate tissues diminishes significantly, leading to symptoms of hypoxemia and potential organ dysfunction. At a PaO2 of approximately 60 mmHg, individuals may exhibit clinical signs of respiratory distress and may require supplemental oxygen or mechanical ventilation to maintain adequate oxygenation. Values above this threshold, while still potentially concerning depending on the patient's overall clinical picture, are typically seen as sufficient to avoid the designation of respiratory failure, as they indicate better pulmonary gas exchange and oxygen delivery to tissues.