Carbon Monoxide:

Asphyxia:

CO belongs to a class of substances known as asphyxiants.

Two Categories of asphyxiants:

• Due to cessation of breathing
  - Mechanical obstruction to normal respiration - strangulation, drowning, confinement in an O₂-less vault, cave-in, exposure to outer space, etc. Also referred to as Stagnant or Central Hypoxia
  - Action of certain drugs which depress the respiratory center - morphine, chloroform. Ditto

• Due to a deficiency of O₂ - No interference with O₂ entering the lungs
  
  - Carbon monoxide - reaction in blood stream interferring with O₂ carriage by blood. Also referred to as Anemic Hypoxia
  - Cyanide - reaction in cells / tissues interfers with O₂ useage by mitochondrial oxidative enzymes in the cells. Also referred to as Histotoxic Hypoxia