Trucker MD
Color blind? CO poisoning? Two common truck questions

For the physicians who see a steady stream of trucking patients, most of their questions relate to life in the truck, life on the road, and what health conditions can threaten a driver’s career.

Color blind?
I can still recognize traffic signals and devices showing the standard red, amber, and green traffic signal colors, but I am definitely a bit color blind. Can I lose my CDL?

Like most color blind drivers, you have adapted to recognizing the difference in the colors. Also lights are designed so that red is always on top or left, yellow in the middle and green on the bottom or right.  

Can you being a bit color blind cause you to lose your CDL? Probably not. Most CDMEs (Commercial Driver Medical Examiners) offer color blind drivers a manual exam that consists of distinguishing these three colors in real time. This means pointing to a red object, yellow object and then a green object. Successfully doing this constitutes a pass.

Carbon monoxide poisoning?
I have been getting sick after spending several nights sleeping in my truck.  My physician says the headaches, nausea, vomiting and mental confusion point to carbon monoxide poisoning. The company I drive for says it could not be CO poisoning because diesel fuel combustion engines don’t produce enough carbon monoxide to make you sick. Why is this?

As you know, diesel engines detonate fuel using pressure and temperature, rather than with an artificial spark. This process operates with excessive oxygen, ensuring a much more complete combustion than is typical in a gasoline engine. That’s why you often hear that diesel engines don’t produce enough CO to make you sick.

It is completely possible to get carbon monoxide poisoning from a diesel engine in a road tractor. Contributing factors such as weather, temperature and engine condition can greatly affect the chance of carbon monoxide poisoning. A good example of this: A driver in a truck with an exhaust problem when it is cold and raining is at greater risk than the same person in the same truck on a sunny day. The reason is the barometric pressure holds the carbon monoxide closer to the ground and allows it to enter the truck.

This CO poisoning topic comes up frequently. In fact, I was recently discussing this with a driver who once had an experience where a neighboring truck was basically pumping diesel fumes straight into the sleeper vent all night. The inside of the sleeper was all hazy and the diesel odor was extremely strong, but it did not cause any health problems beyond teary eyes.

While CO poisoning is possible, I am not quick to say it’s the likely cause. The diagnosis can be made by one test. Do you get better when you are at home for a few days? If the answer is yes, get your exhaust system checked. Also, I suggest you install a carbon monoxide detector in your truck. LL

John McElligott is an MD, Fellow of the American College of Physicians, and medical director of the St. Christopher Trucker Development and Relief Fund. Jeff Heinrich, who serves as the column’s medical editor, has a Doctor of Education degree and is Physician Assistant Certified.

This column is the opinion of the writer and does not necessarily reflect the opinions of Land Line Magazine or its publisher. Please remember everyone’s health situation is different. If you have questions regarding medical issues, consult your personal physician.