Positional asphyxia, also known as postural asphyxia, is a form of asphyxia which occurs when someone's position prevents the person from breathing adequately. Positional asphyxia may be a factor in a significant number of people who die suddenly during restraint by police, prison (corrections) officers or health care staff. Positional asphyxia is also a common cause of death in infants.
- Positional asphyxia is a potential danger of some physical restraint techniques,
- People may die from positional asphyxia by simply getting themselves into a breathing-restricted position they cannot get out of, either through the person's own carelessness, as a consequence of another accident, or where infants are placed in a position where the mouth and nose is blocked, or where the chest may be unable to fully expand.
Research has suggested that restraining a person in a face down position is likely to cause greater restriction of breathing than restraining a person face up. Multiple cases have been associated with the hogtie or hobble prone restraint position. Many law enforcement and health personnel are now taught to avoid restraining people face down or to do so only for a very short period of time.
Risk factors which may increase the chance of death include prolonged (particularly resisted) restraint, obesity, prior cardiac or respiratory problems, and the use of illicit drugs such as cocaine. Other issues in the way the subject is restrained can also increase the risk of death, for example kneeling or otherwise placing weight on the subject and particularly any type of restraint hold around the subject's neck. Research measuring the effect of restraint positions on lung function suggests that restraint which involves bending the restrained person or placing body weight on them, has more effect on their breathing than face down positioning alone.
Other restraint positions
Positional asphyxia is not limited to restraint in a face down position. Restraining a person in a seated position may also reduce the ability to breathe, if the person is pushed forwards with the chest on or close to the knees. The risk will be higher in cases where the restrained person has a high body mass index (BMI) and/or large waist girth. 
Resuscitation of persons who exhibit cardiac arrest following restraint has proven to be difficult. Even in cases where the subject was in the immediate care of paramedics, resuscitation has failed and the subject has died. One group of doctors has presented a method of resuscitation, correcting acidosis in the blood of the victim, which proved effective in their small scale study. This approach appears to be supported by another report of a single case of successful resuscitation.
Debate regarding positional asphyxia
There is a degree of controversy amongst researchers regarding the extent to which restraint positions restrict breathing. Some researchers report that when they conducted laboratory studies of the effects of restraint on breathing and oxygen levels, the effect was limited. Other researchers point out that deaths in real life situations occur after prolonged, violent resistance which has not been studied in laboratory simulations.
Positional asphyxia due to accident or illness
Positional asphyxia may also occur as a result of accident or illness. Olympic track athlete Florence Griffith-Joyner and ex-Major League Baseball player John Marzano both died due to positional asphyxia, the former following an epileptic seizure and the latter following a fall down a flight of stairs.
Positional asphyxia in infants
Positional asphyxia is a common, but usually preventable cause of death in infants. It occurs when an infant is put to sleep or falls asleep in an unsafe sleeping environment or in an unsafe position. Examples of unsafe sleeping environments can include:
- Infant car seats that are not properly buckled
- Beanbag chairs
- Infants sharing a bed with others
- Cribs with mattresses that don't properly fit
- Adult beds
- Cribs with sheepskins, quilts, other soft surfaces
Unsafe sleeping positions include:
- Sleeping face down or on the side
- Sleeping in an infant carrier with head covered, or face against soft surface (including parent's chest)
Prevention of positional asphyxia in infants
- Always put infants to sleep in a safe environment, which includes a crib or bassinet without loose materials or soft bedding and with a mattress that fits correctly.
- Infants are safer sleeping alone.
- Never put an infant into a car seat without buckling it up. Babies can slide down when not buckled and get in a position where their airway is blocked.
- Don't cover up your infant so you can't see him/her.
- Avoid over-heating your baby.
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- Medical examiner says a fall killed John Marzano | Philadelphia Inquirer | 07/18/2008