National Registry of Certified Medical Examiners (NRCME) DOT Practice Exam

What minimum PaO2 level is needed for a driver with a chronic respiratory disorder?

1. 70 mm Hg

2. 55 mm Hg

3. 60 mm Hg

4. 65 mm Hg

The correct answer is: 65 mm Hg

A driver with a chronic respiratory disorder is required to meet specific health standards to ensure safe operations. The minimum partial pressure of oxygen in arterial blood (PaO2) level required for such individuals is critical because it indicates how well the lungs are able to oxygenate the blood. A PaO2 of 65 mm Hg is typically regarded as a baseline threshold, indicating that the individual has adequate oxygenation to maintain safety while driving. Levels below this threshold could lead to hypoxia, which may impair judgement, coordination, and overall driving ability. Therefore, a PaO2 of 65 mm Hg is established as the minimum acceptable level for drivers with chronic respiratory conditions, ensuring that they are less likely to experience oxygen deprivation that could adversely affect their driving performance. Higher PaO2 levels, while suggesting better oxygenation, may not be required as a minimum standard. Levels of 70 mm Hg, 60 mm Hg, and 55 mm Hg are either too high or too low in comparison to this minimum requirement, thereby reinforcing 65 mm Hg as the correct answer.