Other namesAsphyxiation
The neck contains several vulnerable targets for compression, including the carotid arteries and the trachea.
SpecialtyCritical care medicine
Frequency9.8 million unintentional worldwide (2015)[1]
Deaths35,600 worldwide (2015)[2]

Asphyxia or asphyxiation is a condition of deficient supply of oxygen to the body which arises from abnormal breathing.[3] [4] Asphyxia causes generalized hypoxia, which affects all the tissues and organs, some more rapidly than others. There are many circumstances that can induce asphyxia, all of which are characterized by the inability of a person to acquire sufficient oxygen through breathing for an extended period of time. Asphyxia can cause coma or death.

In 2015, about 9.8 million cases of unintentional suffocation occurred which resulted in 35,600 deaths.[1][2] The word asphyxia is from Ancient Greek α- "without" and σφύξις sphyxis, "squeeze" (throb of heart).[5]


Situations that can cause asphyxia include but are not limited to: airway obstruction, the constriction or obstruction of airways, such as from asthma, laryngospasm, or simple blockage from the presence of foreign materials; from being in environments where oxygen is not readily accessible: such as underwater, in a low oxygen atmosphere, or in a vacuum; environments where sufficiently oxygenated air is present, but cannot be adequately breathed because of air contamination such as excessive smoke.

Other causes of oxygen deficiency include but are not limited to:


"Smother" redirects here. For other uses, see Smother (disambiguation).

Smothering is a 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.[6] 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.

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 onto an infant during co-sleeping, an accident that often goes unnoticed and is mistakenly thought to be sudden infant death syndrome.[6] 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 is often ascribed to a killing method that involves simultaneous smothering and compression of the torso.[7] The 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 victim's jaw up. The corpses had no visible injuries, and were supplied to medical schools for money.[8]

Compressive asphyxia

See also: Positional asphyxia

Compressive asphyxia (also called chest compression) is mechanically limiting expansion of the lungs by compressing the torso, preventing breathing. "Traumatic asphyxia" or "crush asphyxia" usually refers to compressive asphyxia resulting from being crushed or pinned under a large weight or force, or in a crowd crush.[9] An example of traumatic asphyxia is a person who jacks up a car to work on it from below, and is crushed by the vehicle when the jack fails.[7] Constrictor snakes such as boa constrictors kill through slow compressive asphyxia, tightening their coils every time the prey breathes out rather than squeezing forcefully. In cases of an adult co-sleeping with an infant ("overlay"), the heavy sleeping adult may move on top of the infant, causing compression asphyxia.

In fatal crowd disasters, compressive asphyxia from being crushed against the crowd causes all or nearly all deaths, rather than blunt trauma from trampling. This is what occurred at the Ibrox disaster in 1971, where 66 Rangers fans died; the 1979 The Who concert disaster where 11 died; the Luzhniki disaster in 1982, when 66 FC Spartak Moscow fans died; the Hillsborough disaster in 1989, where 97 Liverpool fans were crushed to death in an overcrowded terrace, 95 of the 97 from compressive asphyxia, 93 dying directly from it and 3 others from related complications; the 2021 Meron crowd crush where 45 died; the Astroworld Festival crowd crush in 2021, where 10 died; and the Seoul Halloween crowd crush in 2022, where at least 159 died during Halloween celebrations.[10][11]

In confined spaces, people are forced to push against each other; evidence from bent steel railings in several fatal crowd accidents has shown horizontal forces over 4500 N (equivalent to a weight of approximately 450 kg or 1000 lbs). In cases where people have stacked up on each other in a human pile, it has been estimated that those at the bottom are subjected to around 380 kg (840 lbs) of compressive weight.[12]

"Positional" or "restraint" asphyxia is when a person is restrained and left alone prone, such as in a police vehicle, and is unable to reposition themself in order to breathe. The death can be in the vehicle, or following loss of consciousness to be followed by death while in a coma, having presented with anoxic brain damage. The asphyxia can be caused by facial compression, neck compression, or chest compression. This occurs mostly during restraint and handcuffing situations by law enforcement, including psychiatric incidents. The weight of the restraint(s) doing the compression may contribute to what is attributed to positional asphyxia. Therefore, passive deaths following custody restraint that are presumed to be the result of positional asphyxia may actually be examples of asphyxia occurring during the restraint process.

Chest compression is a technique used in various grappling combat sports, where it is sometimes called wringing, either to tire the opponent or as complementary or distractive moves in combination with pinning holds,[13] 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 budō referred to as do-jime;[14] 胴絞, "trunk strangle" or "body triangle")[15] where a participant wraps his or her legs around the opponent's midsection and squeezes them together.[16]

Pressing is a form of torture or execution using compressive 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 as a result of inadequate circulation or perfusion, impaired respiratory effort, or inadequate ventilation.[17] There has long been a scientific debate over whether newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air.[17] It has been demonstrated that high concentrations of oxygen lead to generation of oxygen free radicals, which have a role in reperfusion injury after asphyxia.[18] Research by Ola Didrik Saugstad and others led to new international guidelines on newborn resuscitation in 2010, recommending the use of normal air instead of 100% oxygen.[19][20]

Mechanical asphyxia

Accidental deaths in the United States

Classifications of different forms of asphyxia vary among literature, with differences in defining the concept of mechanical asphyxia being the most obvious.[21]

In DiMaio and DiMaio's 2001 textbook on forensic pathology, mechanical asphyxia is caused by pressure from outside the body restricting respiration.[21] Similar narrow definitions of mechanical asphyxia have occurred in Azmak's 2006 literature review of asphyxial deaths and Oehmichen and Auer's 2005 book on forensic neuropathology.[21] According to DiMaio and DiMaio, mechanical asphyxia encompasses positional asphyxia, traumatic asphyxia, and "human pile" deaths.[21]

In Shkrum and Ramsay's 2007 textbook on forensic pathology, mechanical asphyxia occurs when any mechanical means cause interference with the exchange of oxygen and carbon dioxide in the body.[21] Similar broad definitions of mechanical asphyxia have occurred in Saukko and Knight's 2004 book on asphyxia, and Dolinak and Matshes' 2005 book on forensic pathology.[21] According to Shkrum and Ramsay, mechanical asphyxia encompasses smothering, choking, positional asphyxia, traumatic asphyxia, wedging, strangulation and drowning.[21]

Sauvageau and Boghossian propose in 2010 that mechanical asphyxia should be officially defined as caused by "restriction of respiratory movements, either by the position of the body or by external chest compression", thus encompassing only positional asphyxia and traumatic asphyxia.[21]

First aid

If there are symptoms of mechanical asphyxia, it is necessary to call the Emergency Medical Services.[22] In some countries, such as the US, there may also be self-acting groups of voluntary first responders who have been trained in first aid.[23] In case of mechanical asphyxia, first aid can be provided on your own. In such a situation, you need to do the following:

See also


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  2. ^ a b Wang H, Naghavi M, Allen C, Barber RM, Bhutta ZA, Carter A, et al. (October 2016). "Global, regional, and national life expectancy, all-cause mortality, and cause-specific mortality for 249 causes of death, 1980–2015: a systematic analysis for the Global Burden of Disease Study 2015". Lancet. 388 (10053): 1459–1544. doi:10.1016/s0140-6736(16)31012-1. PMC 5388903. PMID 27733281.
  3. ^ Sasso R, Bachir R, El Sayed M (29 June 2018). "Suffocation Injuries in the United States: Patient Characteristics and Factors Associated with Mortality". Western Journal of Emergency Medicine. 19 (4). Western Journal of Emergency Medicine: 707–714. doi:10.5811/westjem.2018.4.37198. ISSN 1936-9018. PMC 6040911.
  4. ^ Aslam HM, Saleem S, Afzal R, Iqbal U, Saleem SM, Shaikh MW, et al. (2014). ""Risk factors of birth asphyxia"". Italian Journal of Pediatrics. 40 (1). doi:10.1186/s13052-014-0094-2. ISSN 1824-7288. PMC 4300075.
  5. ^ "Asphyxia Origin". Online Etymology Dictionary. Archived from the original on 6 September 2015. Retrieved 19 July 2015.
  6. ^ a b Ferris JA. "Asphyxia". Archived from the original (DOC) on 14 June 2006. Retrieved 1 March 2006.
  7. ^ a b DiMaio V, DiMaio D (2001). "Asphyxia". Forensic Pathology (Second ed.). Boca Raton: CRC Press. ISBN 978-0-8493-0072-1. Archived from the original on 13 May 2016. Deaths Occurring Following the Application of Choke or Carotid Holds
  8. ^ "Burking Law & Legal Definition". Archived from the original on 24 June 2018. Retrieved 7 August 2015.
  9. ^ Ronel A (2 May 2021). "Why the Mount Meron Disaster Happened, and How to Prevent Stampedes? Scientists Explain". Haaretz. Archived from the original on 22 May 2021. Retrieved 22 May 2021. likely to die from what is called traumatic asphyxia – strong pressure on the chest
  10. ^ "Hillsborough inquests: The 96 who died". BBC News. 26 April 2016. Archived from the original on 19 March 2018. Retrieved 22 February 2018.
  11. ^ "Astroworld Festival victims' deaths ruled as accident due to asphyxiation, medical examiner finds". KTRK-TV. 16 December 2021. Archived from the original on 16 December 2021. Retrieved 16 December 2021.
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  13. ^ Ohlenkamp N. "Principles of Judo Choking Techniques". Archived from the original on 21 December 2008. Retrieved 3 March 2006.
  14. ^ "Classification of Waza Names". The Kodokan Judo Institute. Archived from the original on 15 April 2012. Retrieved 4 March 2006. Do-jime is a prohibited technique in Judo nd 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 colloquial term for the guard position
  15. ^ "IJF Referee Rules". International Judo Federation. Archived from the original on 15 April 2012. Retrieved 6 March 2006.
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  18. ^ Kutzsche S, Ilves P, Kirkeby OJ, Saugstad OD (June 2001). "Hydrogen peroxide production in leukocytes during cerebral hypoxia and reoxygenation with 100% or 21% oxygen in newborn piglets". Pediatric Research. 49 (6): 834–42. doi:10.1203/00006450-200106000-00020. PMID 11385146.
  19. ^ ILCOR Neonatal resuscitation Guidelines 2010
  20. ^ "Norwegian paediatrician honoured by University of Athens". Royal Norwegian Embassy in Athens. Archived from the original on 4 March 2016.
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Further reading