Which medical gas is essential in treating carbon monoxide poisoning?

Oxygen is essential in treating carbon monoxide poisoning because it helps to displace carbon monoxide from hemoglobin, the molecule in red blood cells that carries oxygen. When carbon monoxide is inhaled, it binds to hemoglobin much more effectively than oxygen does, leading to a reduced ability of the blood to carry oxygen. Administering pure oxygen can significantly enhance the removal of carbon monoxide from the bloodstream. This is achieved through increased partial pressure of oxygen, which promotes the conversion of carbon monoxide back into carbon dioxide, allowing for its excretion from the body through the lungs.

Helium, nitrogen, and carbon dioxide do not play a significant role in the treatment of carbon monoxide poisoning. While nitrogen is an inert gas, helium is sometimes used in specific therapeutic situations but is not relevant for carbon monoxide exposure. Carbon dioxide may contribute to hypercapnia but does not counteract the harmful effects of carbon monoxide. Therefore, oxygen is the critical gas needed in this scenario for effective treatment and recovery.