Suspended animation
Encyclopedia
Suspended animation is the slowing of life processes by external means without termination. Breathing, heartbeat, and other involuntary functions may still occur, but they can only be detected by artificial means. Extreme cold can be used to precipitate the slowing of an individual's functions; use of this process has led to the developing science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

 of cryonics
Cryonics
Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryopreservation of people or large animals is not reversible with current technology...

. Cryonics is another method of life preservation but it cryopreserves
Cryopreservation
Cryopreservation is a process where cells or whole tissues are preserved by cooling to low sub-zero temperatures, such as 77 K or −196 °C . At these low temperatures, any biological activity, including the biochemical reactions that would lead to cell death, is effectively stopped...

 organisms using liquid nitrogen that will preserve the organism until reanimation. Laina Beasley was kept in suspended animation as a two-celled embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

 for 13 years.

Placing astronauts in suspended animation has been proposed as one way for an individual to reach the end of an interstellar or intergalactic journey, avoiding the necessity for a gigantic generation ship
Generation ship
A generation ship is a hypothetical type of interstellar ark starship that travels across great distances between stars at a speed much slower than the speed of light...

; occasionally the two concepts have been combined, with generations of "caretakers" supervising a large population of frozen passengers.

Since the 1970s, induced hypothermia has been performed for some open-heart surgeries as an alternative to heart-lung machine
Heart-lung machine
Cardiopulmonary bypass is a technique that temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the body. The CPB pump itself is often referred to as a heart–lung machine or "the pump"...

s. Hypothermia, however, provides only a limited amount of time in which to operate and there is a risk of tissue and brain damage for prolonged periods.

Temperature-induced

In June 2005 scientists at the University of Pittsburgh
University of Pittsburgh
The University of Pittsburgh, commonly referred to as Pitt, is a state-related research university located in Pittsburgh, Pennsylvania, United States. Founded as Pittsburgh Academy in 1787 on what was then the American frontier, Pitt is one of the oldest continuously chartered institutions of...

's Safar Center for Resuscitation Research announced they had managed to bring dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s back to life, most of them without brain damage
Brain damage
"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...

, by draining the blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 out of the dogs' bodies and injecting a low temperature solution into their circulatory system
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...

s, which in turn keeps the bodies alive in stasis. After three hours of being clinically dead, their blood was returned to their circulatory systems, and the dogs were revived by delivering an electric shock
Electric shock
Electric Shock of a body with any source of electricity that causes a sufficient current through the skin, muscles or hair. Typically, the expression is used to denote an unwanted exposure to electricity, hence the effects are considered undesirable....

 to their hearts. The heart started pumping the blood around the frozen body, and the dogs were brought back to life.

While most of the dogs were fine, a few of the revived dogs had severe nervous and movement coordination damage, causing them to be mentally disabled, and demonstrating behavior that was deemed "zombie
Zombie
Zombie is a term used to denote an animated corpse brought back to life by mystical means such as witchcraft. The term is often figuratively applied to describe a hypnotized person bereft of consciousness and self-awareness, yet ambulant and able to respond to surrounding stimuli...

" like. This has been pushed further by the media which named them "zombie dogs". There is concern that this technique, if used on humans could result in brain damage similar to those suffered by some of the dogs in the experiment. In extreme cases, doctors can now use induced hypothermia which reduces brain and heart activity to a minimum. This allows doctors to have more time to heal or diagnose a patient.

On 20 January 2006, doctors from the Massachusetts General Hospital
Massachusetts General Hospital
Massachusetts General Hospital is a teaching hospital and biomedical research facility in the West End neighborhood of Boston, Massachusetts...

 in Boston announced they had placed pig
Pig
A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s in suspended animation by a similar technique. The pigs were anaesthetised
Anesthesia
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...

 and a major blood loss was induced. After they lost about half their blood the remaining blood was replaced with a chilled saline solution. As the body temperature reached 10 °C (50 °F) the damaged blood vessel was repaired and the blood was returned. The method was tested 200 times with a 90 percent success rate.

Chemically-induced

An article in the 22 April 2005 issue of the scientific journal Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....

reports success towards inducing suspended animation-like hypothermia
Hypothermia
Hypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...

 in mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

. The findings are significant, as mice do not hibernate in nature. The laboratory of Mark B. Roth at the Fred Hutchinson Cancer Research Center
Fred Hutchinson Cancer Research Center
The Fred Hutchinson Cancer Research Center, is one of the world’s leading cancer research institutes...

 in Seattle, Washington, placed the mice in a chamber containing 80 ppm hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 for a duration of 6 hours. The core body temperature of the mice dropped to 13 degrees Celsius and metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

, as assayed by carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 production and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 use, decreased 10-fold.They also induced hypoxia
Hypoxia (medical)
Hypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...

 on nematode
Nematode
The nematodes or roundworms are the most diverse phylum of pseudocoelomates, and one of the most diverse of all animals. Nematode species are very difficult to distinguish; over 28,000 have been described, of which over 16,000 are parasitic. It has been estimated that the total number of nematode...

 embryos and zebrafish embryos, placing them in suspended animation for hours, and then re-animating them simply by returning the oxygen to the embryos.

Massachusetts General Hospital
Massachusetts General Hospital
Massachusetts General Hospital is a teaching hospital and biomedical research facility in the West End neighborhood of Boston, Massachusetts...

 in Boston
Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...

 announced they had been able to hibernate mice
Mouse
A mouse is a small mammal belonging to the order of rodents. The best known mouse species is the common house mouse . It is also a popular pet. In some places, certain kinds of field mice are also common. This rodent is eaten by large birds such as hawks and eagles...

 using the same method. Their heart rate was slowed down from 500 to 200 beats per minute, respiration fell from 120 to 25 breaths per minute and body temperature dropped to 30°C (natural: 39°C). After 2 hours of breathing air without hydrogen sulfide the mice returned to normal. Further studies are needed to see if the gas had poisonous effects on the brain.

Experiments on sedated sheep and partially-ventilated anesthetized pigs have been unsuccessful, suggesting that application to large mammals may not be feasible.

Human hibernation

There are many research projects currently investigating how to achieve "induced hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...

" in humans. This ability to hibernate humans would be useful for a number of reasons, such as saving the lives of seriously ill or injured people by temporarily putting them in a state of hibernation until treatment can be given. NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 is also casually interested in possibly putting astronauts in hibernation when going on very long space journeys, though they are not funding any research to this effect.

There are cases of accidental human hibernation. The most recent is the case of Mitsutaka Uchikoshi, a Japanese man who survived the cold for 24 days in 2006 without food or water when he fell into a hypothermic state similar to hibernation.

See also

  • Cryonics
    Cryonics
    Cryonics is the low-temperature preservation of humans and animals who can no longer be sustained by contemporary medicine, with the hope that healing and resuscitation may be possible in the future. Cryopreservation of people or large animals is not reversible with current technology...

  • Cryptobiosis
    Cryptobiosis
    Cryptobiosis is an ametabolic state of life entered by an organism in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all metabolic procedures stop, preventing reproduction, development, and repair...

  • Life extension
    Life extension
    Life extension science, also known as anti-aging medicine, experimental gerontology, and biomedical gerontology, is the study of slowing down or reversing the processes of aging to extend both the maximum and average lifespan...

  • Near death experience
    Near death experience
    A near-death experience refers to a broad range of personal experiences associated with impending death, encompassing multiple possible sensations including detachment from the body; feelings of levitation; extreme fear; total serenity, security, or warmth; the experience of absolute dissolution;...

  • Resurrection
    Resurrection
    Resurrection refers to the literal coming back to life of the biologically dead. It is used both with respect to particular individuals or the belief in a General Resurrection of the dead at the end of the world. The General Resurrection is featured prominently in Jewish, Christian, and Muslim...


External links

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