Certified Transport Registered Nurse Certification Practice Exam

When PaO2 is unknown, what should FiO2 be started at?

1. 50%

2. 75%

3. 100%

4. 25%

The correct answer is: 100%

When the partial pressure of oxygen in arterial blood (PaO2) is unknown, initiating supplemental oxygen therapy generally begins at 100% FiO2. This approach is taken to ensure that the patient receives maximum oxygen delivery in emergency situations where the patient's oxygenation status is not clearly defined. Starting at 100% FiO2 allows for rapid correction of hypoxemia, which can be critical in managing conditions such as respiratory distress, shock, or other scenarios where oxygen saturation may be compromised. This high level of oxygen can help determine how well the patient responds and what adjustments may be necessary based on subsequent assessments of oxygenation, such as checking arterial blood gases or pulse oximetry results. After stabilization and evaluation, the FiO2 can be titrated down to the lowest effective concentration to maintain adequate oxygen saturation levels, minimizing the risk of oxygen toxicity. This is an essential nursing practice in transport settings, where rapid decisions can significantly impact patient outcomes.