Asphyxia

Asphyxia
Specialty	Emergency medicine

Suffocation redirects here, for the band, see Suffocation (band).

Asphyxia (from Greek a-, "without" and sphuxis, "pulse, heartbeat") is a condition of severely deficient supply of oxygen to the body that arises from being inable to breathe normally. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs most sensitive to hypoxia first, such as the brain, hence resulting in cerebral hypoxia. Asphyxia is characterized by air hunger, and in the absence of effective remedial action it will very rapidly lead to unconsciousness, brain damage and death.

Asphyxiation or suffocation refer to the process of asphyxia, where the body becomes increasingly hypoxic.

General

Asphyxiation is typically the result of various accidents. It is also the desired effect of various asphyxiation techniques, in which the aim is to cause asphyxia by partially or fully interfering with normal breathing. Asphyxiation techniques are used to maim or kill in capital punishment, suicide, torture, violence and warfare. They are also used non-fatally in martial arts, combat sports, BDSM and erotic asphyxia. Asphyxiation is typically caused by one of the following three different mechanisms:

• Inadequate availability of oxygen in the environment.
• Physical obstruction of the flow of air to or from the environment to the lungs.
• Chemical interference with breathing mechanism or with the chemical absorption of oxygen in the lungs.

The constriction of the artieries and/or veins in the neck such as in certain types of strangulations, do not cause asphyxia, but rather direct cerebral hypoxia.

List of causes of asphyxia

• Inadequate availability of oxygen in the environment
  • The filling of cryogenic vessels with liquified, oxygen-free gases such as nitrogen in an enclosed space
  • Workers climbing down into a fermentation vat in a brewery, not realising the vessel has filled with carbon dioxide gas
  • Workers climbing down into the holds of ships that contain heavier than air, oxygen-free gases
  • The misuse or failure of diving rebreathers where the breathing gas contains insufficient oxygen.
  • Breathing a hypoxic breathing gas mixture while diving in shallow water where the partial pressure of oxygen is too low to support consciousness. A hypoxic "bottom gas" is designed only to be breathed at depth.
  • Inhalation of overwhelming amounts of non-oxygen gases (such as helium) for recreational or amusement purposes.
• Physical obstruction of the flow of air to or from the environment to the lungs
  • Crushing or constriction of the chest or abdomen
  • Choking
  • Drowning
  • Strangulation, or external constriction of the neck or throat, e.g. by a rope (as in hanging), hands, or a constrictor snake
  • Reduction of the airways due to anaphylaxis or asthma
  • Inhalation of vomit
  • Positional asphyxia
  • The practice of erotic asphyxiation, also called "breath control play"
  • The choking game Children (9-16 years old) participating in an extremely dangerous and often deadly activity to get a rush or 'high'
• Chemical interference with the breathing mechanism or with the chemical absorption of oxygen in the lungs
  • A seizure which stops breathing activity
  • Sleep apnea
  • Contact with a pulmonary agent or cyanogenic compound
  • Drug overdose
  • Self-induced hypocapnia by hyperventilation followed by a breath hold. This is the basis for the schoolyard choking game and can be fatal; the mechanism is described in detail in shallow water blackout.
  • Ondine's curse, central alveolar hypoventilation syndrome, or primary alveolar hypoventilation, a disorder of the autonomic nervous system in which a patient must conciously breathe and will die if they fall asleep

Problems during childbirth can lead to the newborn experiencing asphyxia (asphyxia neonatorum).

Smothering

Smothering refers to the mechanical obstruction the flow of air from the environment into the mouth and/or nostrils, for instance by covering the mouth and nose with a hand or a plastic bag. 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. Normally, smothering requres atleast 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, 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. Other accidents involving a similar mechanism are cave-ins or when an individual is buried in sand or grain. In homicidal cases, the term burkingTemplate:Fn is often ascribed to a killing method that involves simoultaneous smothering and compression of the torso.

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

Compressive asphyxia

Compressive asphyxia (also called chest compression) refers to 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 . In accidents, the term traumatic asphyxia or crush asphyxia is usually used to describe compressive asphyxia resulting form being crushed or pinned under a large weight or force. An example of traumatic asphyxia include cases where an individual has been using a car-jack to repair a car from below; the car-jack slips and they are crushed under the weight of the vehicle. In fatal crowd disasters, such as the Heysel Stadium disaster, traumatic asphyxia is called riot-crush. Contrary to popular belief, it is not the blunt trauma from trampling that causes the large part of the deaths in such cases, 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 forimg a human pile, estimations have been made of around 380kg of compressive weight in the lowest layer.

Chest compression is also featured in various grappling combat sports, where it is sometimes called wringing. Such techniques are either used to tire the opponent, or as complementary or distractive moves in combination with pinning holds, or sometimes even as a submission holds. Examples of chest compression include the the knee-on-stomach position, or techniques such as leg scissors (in budo referred to as do-jimeTemplate:Fn, "trunk technique") where you wrap the legs around the opponent's midsection and squeeze them together.

Notes

• Template:Fnb Do-jime (also called leg scissors) is an illegal technique in Judo competition, and is considered a 'slight infringement' according to IJF rules, Section 27: Prohibited acts and penalties, article 21. It should not be confused with do-osae, which is a colloquially used term for the guard.
• Template:FnbIn a experiment where dogs were suffocated by placing an air-tight rubber mask over the dog's heads, it was shown that it took around 8 minutes for the dogs to go into cardiac arrest. Breathing movements continued and the animals engaged in violent struggle or had convulsions until the point of death. This can be contrasted with another experiment in dogs were suffocated by forcing them to breathe nitrogen, the dogs surviving only an average of 5 minutes. The reason is considered to be loss of oxygen into the environment when the animals were able to breathe freely.
• Template:FnbThe term "burking" comes from the method William Burke and William Hare used to kill their victims during the West Port murders. They killed the usually intoxicated victims by sitting on their chests and suffocating them by putting a hand over their nose and mouth, while using the other hand to push the victims jaw up. The corpses had no visible injuries, and were supplied medical schools for money.

References

Main reference:

• Ferris, J.A.J. Asphyxia, Drowning. www.pathology.ubc.ca. URL accessed on March 1 2006. (DOC format)

Other references:

External links

• Do-Jime. Image of a torso compression technique.
• Cross-side to chest compression choke