Asphyxia

Asphyxia (from Greek a-, "without" and σφυγμός (sphygmos), "pulse, heartbeat") is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. An example of asphyxia is choking. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs.

• 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 it 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
• Breathing an industrial atmosphere lacking oxygen (e.g. welding gases, or in containers purged with nitrogen).

Smothering

Smothering is the mechanical obstruction of the flow of air from the environment into the mouth and/or nostrils, for instance, by covering the mouth and nose with a hand, pillow, or a plastic bag.^[1] Smothering can be either partial or complete, where partial indicates that the person being smothered is able to inhale some air, although less than required. In a normal situation, smothering requires at least partial obstruction of both the nasal cavities and the mouth to lead to asphyxia. Smothering with the hands or chest is used in some combat sports to distract the opponent, and create openings for transitions, as the opponent is forced to react to the smothering. It is also used in BDSM as a type of facesitting.

In some cases, when performing certain routines, smothering is combined with simultaneous compressive asphyxia. One example is overlay, in which an adult accidentally rolls over an infant during co-sleeping, an accident that often goes unnoticed and is mistakenly thought to be sudden infant death syndrome.^[1] Other accidents involving a similar mechanism are cave-ins or when an individual is buried in sand or grain. In homicidal cases, the term burking^[2] is often ascribed to a killing method that involves simultaneous smothering and compression of the torso.^[3]

Compressive asphyxia

The knee-on-belly position compresses the chest, making it difficult for the person on the bottom to breathe.

Compressive asphyxia (also called chest compression) is the mechanical limitation of the expansion of the lungs by compressing the torso, hence interfering with breathing. Compressive asphyxia occurs when the chest or abdomen is compressed posteriorly.^[4] In accidents, the term traumatic asphyxia or crush asphyxia is usually used to describe compressive asphyxia resulting from being crushed or pinned under a large weight or force. An example of traumatic asphyxia includes cases in which an individual has been using a car-jack to repair a car from below, only to be crushed under the weight of the vehicle^[3] when the car-jack slips. Pythons, anacondas, and other constrictor snakes kill through compressive asphyxia.

In fatal crowd disasters, contrary to popular belief, it is not the blunt trauma from trampling that causes the large part of the deaths, but rather the compressive asphyxia from being crushed against the crowd. In confined spaces, people push and lean against each other; evidence from bent steel railings in several fatal crowd accidents have shown horizontal forces over 4500 N (comparative weight approximately 460kg). In cases where people have stacked up on each other forming a human pile, estimations have been made of around 380kg of compressive weight in the lowest layer.^[5]

The cause of death of detainees who have been restrained and left prone, for example in police vehicles, and are unable to move into safer positions has been referred to as 'positional asphyxia'.

Chest compression is also featured in various grappling combat sports, where it is sometimes called wringing. Such techniques are used either to tire the opponent or as complementary or distractive moves in combination with pinning holds,^[6] or sometimes even as submission holds. Examples of chest compression include the knee-on-stomach position, or techniques such as leg scissors (also referred to as body scissors and in budo referred to as do-jime,^[7] 胴絞, "trunk strangle" or "body triangle")^[8] where you wrap the legs around the opponent's midsection and squeeze them together.^[9]

Pressing is a form of torture or execution that works through asphyxia.

Perinatal asphyxia

Main article: Perinatal asphyxia

Perinatal asphyxia is the medical condition resulting from deprivation of oxygen (hypoxia) to a newborn infant long enough to cause apparent harm. It results most commonly from a drop in maternal blood pressure or interference during delivery with blood flow to the infant's brain. This can occur due to inadequate circulation or perfusion, impaired respiratory effort, or inadequate ventilation. Perinatal asphyxia happens in 2 to 10 per 1000 newborns that are born at term.

References

Further reading

• The Physiology, Pathology, and Treatment of Asphyxia by James Phillips Kay-Shuttleworth, 1834, 352 pages.
• Elsner R (September 1989). "Perspectives in diving and asphyxia". Undersea Biomed Res 16 (5): 339–44. PMID 2678664. http://archive.rubicon-foundation.org/2500. Retrieved on 2008-07-04. 

External links

• Cross-side to chest compression choke