Asphyxia - Oxygen Deficiency

Oxygen Deficiency

The body creates the need to breathe from the excess carbon dioxide in the blood. The body has chemosensors to detect oxygen levels in the blood, but these don't typically control respiratory rate. Many gases, though non-toxic, are classified as simple asphyxiants in their pure form or in high concentrations for this very reason.

One form of asphyxiation is from entering a low oxygen atmosphere or an inert atmosphere, such as in a food oil tank that has a covering blanket of nitrogen or argon to shield the oil from atmospheric oxygen. Without sufficient oxygen to sustain life, people will act normally at first but will then abruptly feel dizzy and black out in a matter of seconds as the remaining oxygen in the blood stream is consumed. Oxygen deficient atmospheres are the basis for many occurrences of single and multiple deaths; the deceased will be found lying prone on the bottom of a tank, and then the observer will rush in to rescue them, and succumb to the same effect, hence the need to vent or purge the inert gases from all tanks before entry.

Other causes of oxygen deficiency include:

• Carbon monoxide inhalation, such as from a car exhaust: carbon monoxide has a higher affinity than oxygen to the hemoglobin in the blood's red blood corpuscles, bonding with it tenaciously, and, in the process, displacing oxygen and preventing the blood from transporting oxygen around the body
• Contact with certain chemicals, including pulmonary agents (such as phosgene) and blood agents (such as hydrogen cyanide)
• Self-induced hypocapnia by hyperventilation, as in shallow water or deep water blackout and the choking game
• A seizure which stops breathing activity
• Sleep apnea
• Drug overdose
• Ondine's curse, central alveolar hypoventilation syndrome, or primary alveolar hypoventilation, a disorder of the autonomic nervous system in which a patient must consciously breathe; although it is often said that persons with this disease will die if they fall asleep, this is not usually the case
• Acute respiratory distress syndrome.
• Exposure to extreme low pressure or vacuum to the pattern
• Hanging
• Respiratory diseases
• Drowning