A Wayne State University School of Medicine toxicologist and his colleagues warn in a letter published in the New England Journal of Medicine that mud bogging may poison participants of the motor sport.
Mud bogging is the driving of modified vehicles, including pickup trucks and sport utility vehicles, in trenches of deep mud and water. Drivers compete to determine whether they can successfully transit the obstacle, or see who can drive the farthest before their vehicle conks out or becomes bogged down. The competitions, which have their genesis in the southern United States, have spread throughout the country and into Canada.
Andrew King, M.D., Wayne State University assistant professor of Emergency Medicine, and a medical toxicologist and emergency physician for the Detroit Medical Center, and colleagues have found that participants run the risk of carbon monoxide poisoning.
In a letter published Sept. 10 in the New England Journal of Medicine, Dr. King cites two incidents in which mud bogging competitors were treated for carbon monoxide poisoning.
In the first case, an 18-year-old male driver and a 16-year-old female passenger lost consciousness while mud bogging. Upon arrival at an emergency room, their carboxyhemoglobin levels were 18.5 percent and 15 percent, respectively. Normal levels of carbon monoxide in the bloodstream are less than 2 percent. In smokers, that may rise to 10 percent. Severe symptoms are generally seen at levels greater than 25 percent.
The patients were treated with 90-minute sessions of hyperbaric oxygen. Both declined further treatment.
The second case involved two male passengers, ages 16 and 19, who lost consciousness in the rear seat of a vehicle while mud bogging. Both were treated with hyperbaric oxygen sessions until symptoms resolved.
Those affected in the mud bogging incidents cited may develop so-called "delayed neurological sequelae," which are ill-defined neurological deficits that may not appear until a month or so after exposure, Dr. King said. The hyperbaric treatment seeks to prevent or mitigate those effects.
The carbon monoxide poisoning most likely results when the exhaust pipes of the vehicles become filled with mud, forcing the gas to flood the passenger cabins. Because the gas is colorless, odorless and tasteless, drivers and passengers may not realize they are being poisoned.
Because early detection of carbon monoxide exposure is theoretically beneficial, portable battery-powered detectors may help prevent carbon monoxide poisoning if installed in the passenger compartments of mud bogging vehicles. Such units are available at many hardware stores.
"Maximizing ventilation by keeping the windows open is also likely helpful," Dr. King said, "but the best way to avoid exposure is avoidance of the activity all together."
His coauthors of the letter, Nathan Menke, M.D., Ph.D.; Katherine Fitzpatrick, M.D.; and Michael Lynch, M.D.; are colleagues at the University of Pittsburgh Medical Center, where Dr. King completed his residency and fellowship. The cases cited occurred in West Virginia, and the patients were treated at the University of Pittsburgh Medical Center.