Last updated

Other namesAsphyxiation
The neck contains several vulnerable targets for compression, including the carotid arteries and the trachea.
Specialty Critical care medicine
Complications Coma
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.[ citation needed ] 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 σφύξιςsphyxis, "squeeze" (throb of heart). [3]


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:


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. [4] 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. [4] 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. [5] 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. [6]

Compressive 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. [7] 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. [5] 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. [8] [9]

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. [10]

"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, [11] 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; [12] 胴絞, "trunk strangle" or "body triangle") [13] where a participant wraps his or her legs around the opponent's midsection and squeezes them together. [14]

Pressing is a form of torture or execution using compressive asphyxia.

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. [15] There has long been a scientific debate over whether newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air. [15] 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. [16] 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. [17] [18]

Mechanical asphyxia

Accidental deaths in the United States
Accidental deaths 2020.webp

Accidental deaths 2004 in the United States.webp

Classifications of different forms of asphyxia vary among literature, with differences in defining the concept of mechanical asphyxia being the most obvious. [19]

In DiMaio and DiMaio's 2001 textbook on forensic pathology, mechanical asphyxia is caused by pressure from outside the body restricting respiration. [19] 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. [19] According to DiMaio and DiMaio, mechanical asphyxia encompasses positional asphyxia, traumatic asphyxia, and "human pile" deaths. [19]

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. [19] 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. [19] According to Shkrum and Ramsay, mechanical asphyxia encompasses smothering, choking, positional asphyxia, traumatic asphyxia, wedging, strangulation and drowning. [19]

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. [19]

First aid

If there are symptoms of mechanical asphyxia, it is necessary to call the Emergency Medical Services. [20] 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. [21] 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

Related Research Articles

<span class="mw-page-title-main">First aid</span> Emergency first response medical treatment

First aid is the first and immediate assistance given to any person with either a minor or serious illness or injury, with care provided to preserve life, prevent the condition from worsening, or to promote recovery until medical services arrive. First aid is generally performed by someone with basic medical training. Mental health first aid is an extension of the concept of first aid to cover mental health, while psychological first aid is used as early treatment of people who are at risk for developing PTSD. Conflict first aid, focused on preservation and recovery of an individual's social or relationship well-being, is being piloted in Canada.

<span class="mw-page-title-main">Choking</span> Mechanical obstruction of the flow of air from the environment into the lungs

Choking, also known as foreign body airway obstruction (FBAO), is a phenomenon that occurs when breathing is impeded by a blockage inside of the respiratory tract. An obstruction that prevents oxygen from entering the lungs results in oxygen deprivation. Although oxygen stored in the blood and lungs can keep a person alive for several minutes after breathing stops, choking often leads to death.

<span class="mw-page-title-main">Positional asphyxia</span> Inability to breathe due to body position or posture

Positional asphyxia, also known as postural asphyxia, is a form of asphyxia which occurs when someone's position prevents the person from breathing adequately. People may die from positional asphyxia accidentally, when the mouth and nose are blocked, or where the chest may be unable to fully expand.

<span class="mw-page-title-main">Strangling</span> Compression of the neck that may lead to unconsciousness or death

Strangling is compression of the neck that may lead to unconsciousness or death by causing an increasingly hypoxic state in the brain. Fatal strangling typically occurs in cases of violence, accidents, and is one of two main ways that hanging causes death.

<span class="mw-page-title-main">Hogtie</span> Physical restraint by tying the limbs together

The hogtie is a method of tying the limbs together, rendering the subject immobile and helpless. Originally, it was applied to pigs and other young four-legged animals.

Transient tachypnea of the newborn is a respiratory problem that can be seen in the newborn shortly after delivery. It is caused by retained fetal lung fluid due to impaired clearance mechanisms. It is the most common cause of respiratory distress in term neonates. It consists of a period of tachypnea (rapid breathing. Usually, this condition resolves over 24–72 hours. Treatment is supportive and may include supplemental oxygen and antibiotics. The chest x-ray shows hyperinflation of the lungs including prominent pulmonary vascular markings, flattening of the diaphragm, and fluid in the horizontal fissure of the right lung.

<span class="mw-page-title-main">Atelectasis</span> Partial collapse of a lung causing reduced gas exchange

Atelectasis is the partial collapse or closure of a lung resulting in reduced or absent gas exchange. It is usually unilateral, affecting part or all of one lung. It is a condition where the alveoli are deflated down to little or no volume, as distinct from pulmonary consolidation, in which they are filled with liquid. It is often referred to informally as a collapsed lung, although more accurately it usually involves only a partial collapse, and that ambiguous term is also informally used for a fully collapsed lung caused by a pneumothorax.

Erotic asphyxiation is the intentional restriction of oxygen to the brain for the purposes of sexual arousal. The term autoerotic asphyxiation is used when the act is done by a person to themself. Colloquially, a person engaging in the activity is sometimes called a gasper. Erotic asphyxiation can lead to accidental death due to asphyxia.

Perinatal asphyxia is the medical condition resulting from deprivation of oxygen to a newborn infant that lasts long enough during the birth process to cause physical harm, usually to the brain. It remains a serious condition which causes significant mortality and morbidity. It is also the inability to establish and sustain adequate or spontaneous respiration upon delivery of the newborn, an emergency condition that requires adequate and quick resuscitation measures. Perinatal asphyxia is also an oxygen deficit from the 28th week of gestation to the first seven days following delivery. It is also an insult to the fetus or newborn due to lack of oxygen or lack of perfusion to various organs and may be associated with a lack of ventilation. In accordance with WHO, perinatal asphyxia is characterised by: profound metabolic acidosis, with a pH less than 7.20 on umbilical cord arterial blood sample, persistence of an Apgar score of 3 at the 5th minute, clinical neurologic sequelae in the immediate neonatal period, or evidence of multiorgan system dysfunction in the immediate neonatal period. Hypoxic damage can occur to most of the infant's organs, but brain damage is of most concern and perhaps the least likely to quickly or completely heal. In more pronounced cases, an infant will survive, but with damage to the brain manifested as either mental, such as developmental delay or intellectual disability, or physical, such as spasticity.

<span class="mw-page-title-main">Cerebral hypoxia</span> Oxygen shortage of the brain

Cerebral hypoxia is a form of hypoxia, specifically involving the brain; when the brain is completely deprived of oxygen, it is called cerebral anoxia. There are four categories of cerebral hypoxia; they are, in order of increasing severity: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury.

<span class="mw-page-title-main">Chokehold</span> Submission hold that reduces air or blood flow

A chokehold, choke, stranglehold or, in Judo, shime-waza is a general term for a grappling hold that critically reduces or prevents either air (choking) or blood (strangling) from passing through the neck of an opponent. The restriction may be of one or both and depends on the hold used and the reaction of the victim. While the time it takes for the choke to render an opponent unconscious varies depending on the type of choke, the average across all has been recorded as 9 seconds.

The choking game, or fainting game is the act of intentionally cutting off oxygen to the brain with the goal of inducing temporary loss of consciousness and euphoria. A related internet challenge, the blackout challenge, encourages the use of the choking game online.

<span class="mw-page-title-main">Respiratory disease</span> Disease of the respiratory system

Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.

<span class="mw-page-title-main">Intrauterine hypoxia</span> Medical condition when the fetus is deprived of sufficient oxygen

Intrauterine hypoxia occurs when the fetus is deprived of an adequate supply of oxygen. It may be due to a variety of reasons such as prolapse or occlusion of the umbilical cord, placental infarction, maternal diabetes and maternal smoking. Intrauterine growth restriction may cause or be the result of hypoxia. Intrauterine hypoxia can cause cellular damage that occurs within the central nervous system. This results in an increased mortality rate, including an increased risk of sudden infant death syndrome (SIDS). Oxygen deprivation in the fetus and neonate have been implicated as either a primary or as a contributing risk factor in numerous neurological and neuropsychiatric disorders such as epilepsy, attention deficit hyperactivity disorder, eating disorders and cerebral palsy.

Inert gas asphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air. Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium, nitrogen and methane. The term "physiologically inert" is used to indicate a gas which has no toxic or anesthetic properties and does not act upon the heart or hemoglobin. Instead, the gas acts as a simple diluent to reduce the oxygen concentration in inspired gas and blood to dangerously low levels, thereby eventually depriving cells in the body of oxygen.

Traumatic asphyxia, or Perte's syndrome, is a medical emergency caused by an intense compression of the thoracic cavity, causing venous back-flow from the right side of the heart into the veins of the neck and the brain.

An asphyxiant gas, also known as a simple asphyxiant, is a nontoxic or minimally toxic gas which reduces or displaces the normal oxygen concentration in breathing air. Breathing of oxygen-depleted air can lead to death by asphyxiation (suffocation). Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia).

Persistent fetal circulation is a condition caused by a failure in the systemic circulation and pulmonary circulation to convert from the antenatal circulation pattern to the "normal" pattern. Infants experience a high mean arterial pulmonary artery pressure and a high afterload at the right ventricle. This means that the heart is working against higher pressures, which makes it more difficult for the heart to pump blood.

<span class="mw-page-title-main">Neonatal resuscitation</span>

Neonatal resuscitation, also known as newborn resuscitation, is an emergency procedure focused on supporting approximately 10% of newborn children who do not readily begin breathing, putting them at risk of irreversible organ injury and death. Many of the infants who require this support to start breathing breath well on their own after assistance. Through positive airway pressure, and in severe cases chest compressions, medical personnel certified in neonatal resuscitation can often stimulate neonates to begin breathing on their own, with attendant normalization of heart rate.

<span class="mw-page-title-main">Crowd collapses and crushes</span> Type of disaster that occurs due to overcrowding

Crowd collapses and crowd crushes are catastrophic incidents that can occur when a body of people becomes dangerously overcrowded. When numbers are up to about five people per square meter, the environment may feel cramped but manageable; when numbers reach between eight and ten people per square meter, individuals become pressed against each other and may be swept along against their will by the motion of the crowd. Under these conditions, the crowd may undergo a progressive collapse where the pressure pushes people off their feet, resulting in people being trampled or crushed by the weight of other people falling on top of them. At even higher densities, the pressure on each individual can cause them to be crushed or asphyxiated while still upright.


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