what happens if you choke someone out
1 Our bodies use oxygen as a fuel source to make energy from the food we eat. Carbon dioxide, a waste product, enters the bloodstream and travels back to the lungs. 2  When we exhale, we breathe out carbon dioxide, nitrogen, and oxygen.  When someone is choking with a completely blocked airway, no oxygen can enter the lungs. The brain is extremely sensitive to this lack of oxygen and begins to die within four to six minutes. It is during this time that first aid must take place. Irreversible brain death occurs in as little as 10 minutes.