Often oxygen is administered. In severe cases, patients are treated in a pressurized oxygen chamber called a hyperbaric chamber which quickly and thoroughly forces the carbon monoxide from the body. Many hours, even days, may be required for carbon monoxide to be eliminated from the body unassisted. During this time, additional damage can occur. Yes, continued exposure to carbon monoxide can cause permanent brain, nerve, or heart damage.
Some people require years of recovery, while others remain permanently incapacitated.
If the person lost consciousness they typically will have relapses for several weeks and continue to suffer from headaches, fatigue, loss of memory, difficulty thinking, irrational behavior, and irritability. And third, replace heating units with direct-vent sealed combustion units.