Carbon dioxide (CO2) is a waste product of cellular metabolism. You get rid of it when you breathe out (exhale). This gas is transported in the opposite direction to oxygen: It passes from the bloodstream – across the lining of the air sacs – into the lungs and out into the open.

Carbon monoxide poisoning occurs when carbon monoxide builds up in your bloodstream. When too much carbon monoxide is in the air, your body replaces the oxygen in your red blood cells with carbon monoxide. This can lead to serious tissue damage, or even death.

Carboxyhemoglobin: Hemoglobin that has carbon monoxide instead of the normal oxygen bound to it. Carbon monoxide has a much stronger binding to hemoglobin than oxygen.

Carboxyhemoglobin is formed in carbon monoxide poisoning and leads to oxygen deficiency in the body.

Carbon Monoxide’s toxicity is due to its high affinity for hemoglobin, 230 times that of oxygen, resulting in an inadequate blood supply to an organ or part of the body, especially the heart muscles.

CO is produced by incomplete combustion of organic matter such as gasoline or wood. It is a common byproduct present in the exhaust of motor vehicles, heaters, and cooking equipment, along with many other substances generated during combustion. When CO binds to hemoglobin, it is called carboxyhemoglobin, as opposed to oxyhemoglobin when oxygen is bound. Chronic smokers have been known to have carboxyhemoglobin levels of up to 9–12%, with normal being less than 1%.

When patients succumb to the toxic effects of inhalation of combustion products, one of the first symptoms reported is headache, followed by more severe headache, vertigo, and nausea at higher concentrations and longer exposure times. Convulsions, respiratory arrest, and death result at the highest concentrations of CO. Importantly, many of the substances found in exhaust are potently toxic including carbon particulate, benzo-a-pyrene and even NO.

Hypercapnia (from the Greek hyper = “above” or “too much” and kapnos = “smoke”), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous product of the body’s metabolism and is normally expelled through the lungs.

Mild symptoms of hypercapnia or hypercarbia include:

  • flushed skin
  • drowsiness or inability to focus
  • mild headaches
  • feeling disoriented or dizzy
  • feeling short of breath
  • being abnormally tired or exhausted

Severe symptoms of hypercapnia or hypercarbia include:

  • unexplained feelings of confusion
  • abnormal feelings of paranoia or depression
  • abnormal muscle twitching
  • irregular heartbeat
  • hyperventilation
  • seizures
  • panic attack
  • passing out