Situations that can cause asphyxia include but are not limited to:
airway obstruction (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: •
Acute respiratory distress syndrome •
Alcohol poisoning •
Carbon monoxide inhalation, such as that from a
car exhaust and the smoke produced by a lit
cigarette: 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) •
Choking by obstruction of a foreign body in the airway (for example: when eating) •
Cyanide poisoning •
Drowning •
Drug overdose • Exposure to extreme low pressure or
vacuum from
spacesuit damage (see
space exposure) •
Hanging, whether suspension or short drop hanging • Self-induced
hypocapnia by
hyperventilation, as in
shallow water or
deep water blackout and the
choking game •
Inert gas asphyxiation •
Congenital central 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 people with this disease will die if they fall asleep, this is not usually the case. •
Respiratory diseases •
Sleep apnea • A
seizure which stops breathing activity • An
allergic reaction •
Strangling • Breaking the
wind pipe • Prolonged exposure to
chlorine gas Smothering Smothering is a mechanical obstruction of the flow of air from the environment into the mouth or nostrils. 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. 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.
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. 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. 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. "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, 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; 胴絞, "trunk strangle" or "body triangle") where a participant wraps his or her legs around the opponent's midsection and squeezes them together.
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. There has long been a scientific debate over whether
newborn infants with asphyxia should be resuscitated with 100% oxygen or normal air. 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.
Mechanical asphyxia Classifications of different forms of asphyxia vary among literature, with differences in defining the concept of mechanical asphyxia being the most obvious. In DiMaio and DiMaio's 2001 textbook on forensic pathology, mechanical asphyxia is caused by pressure from outside the body restricting respiration. 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. According to DiMaio and DiMaio, mechanical asphyxia encompasses positional asphyxia, traumatic asphyxia, and "human pile" deaths. 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. 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. According to Shkrum and Ramsay, mechanical asphyxia encompasses smothering, choking, positional asphyxia, traumatic asphyxia, wedging, strangulation and drowning. 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. == First aid ==