Editing Suspended animation

{{Short description|Slowing or stopping of life without death}}
{{Other uses}}
{{Use dmy dates|date=June 2017}}
{{Cleanup|reason=the article has problems with clarity, grammar, spacing, punctuation and tone.|date=June 2017}}
[[File:Intrahospital CPR.jpg|thumb|Cardiopulmonary resuscitation (CPR) being performed on a trauma patient in a hospital of [[Maracay]], Venezuela. Like CPR, suspended animation could delay the onset of cell  death (necrosis) in seriously injured or ill patients, providing them with more time to receive definitive medical treatment.]]

'''Suspended animation''' is the slowing or stopping of biological function so that physiological capabilities are preserved. States of suspended animation are common in micro-organisms and some plant tissue, such as seeds. Many animals, including large ones, may undergo [[hibernation]], and most plants have periods of [[dormancy]]. This article focuses primarily on the potential of large animals, especially humans, to undergo suspended animation.

In animals, suspended animation may be either hypometabolic or ametabolic in nature. It may be induced by either endogenous, natural or artificial biological, chemical or physical means. In its natural form, it may be spontaneously reversible as in the case of species demonstrating hypometabolic states of [[hibernation]]. When applied with therapeutic intent, as in [[deep hypothermic circulatory arrest]] (DHCA), usually technologically mediated revival is required.<ref>{{cite news|url=http://medical-dictionary.thefreedictionary.com/suspended+animation| title=Suspended Animation |publisher=Medical-Dictionary.thefreedictionary.com}}</ref><ref>{{cite journal|pmc=4060059| title=Is pharmacological, H2S-induced 'suspended animation' feasible in the ICU?|journal=Crit Care|volume=18|issue=2|page=215|date=2014|doi=10.1186/cc13782| last1=Asfar| first1=P| last2=Calzia| first2=E| last3=Radermacher| first3=P| pmid=25028804| doi-access=free}}</ref>

== Basic principles ==
Suspended animation is understood as the pausing of [[Biological process|life process]]es by external or internal means without terminating [[life]] itself.<ref>{{Cite journal|last=Asfar|first=P.|date=2014|title=Is pharmacological, H2S-induced 'suspended animation' feasible in the ICU?|journal=Critical Care|volume=182|issue=2|pages=215|doi=10.1186/cc13782|pmid=25028804|pmc=4060059 |doi-access=free }}</ref> Breathing, heartbeat and other involuntary functions may still occur, but they can only be detected by artificial means.<ref>{{cite magazine|url=https://www.scientificamerican.com|title=How do frogs survive winter? Why don't they freeze to death?|magazine=Scientific American|date=11 July 2014|access-date=3 June 2017}}</ref> For this reason, this procedure has been associated with a lethargic state in nature when animals or plants appear, over a period, to be dead but then can wake up or prevail without suffering any harm. This has been termed in different contexts [[hibernation]], [[dormancy]] or [[anabiosis]] (the latter in some aquatic invertebrates and plants in scarcity conditions).

[[File:13C and 15N incorporation in representative microbial cells.webp|thumb|right|200px|Revived microbial life in very old marine sediment]]

In July 2020, [[Marine biology|marine biologists]] reported that [[Aerobic organism|aerobic]] [[microorganism]]s (mainly), in "quasi-suspended animation", were found in [[Sediment|organically-poor sediments]], up to 101.5 million years old, {{convert|68.9|m|ft|abbr=off}} below the [[Seabed|sea floor]] in the [[South Pacific Gyre]] (SPG) ("the deadest spot in the ocean"), and could be the [[List of longest-living organisms|longest-living life forms]] ever found.<ref name="NYT-2200728">{{cite news |last=Wu |first=Katherine J. |title=These Microbes May Have Survived 100 Million Years Beneath the Seafloor - Rescued from their cold, cramped and nutrient-poor homes, the bacteria awoke in the lab and grew. |work=The New York Times |url=https://www.nytimes.com/2020/07/28/science/microbes-100-million-years-old.html |date=28 July 2020 |access-date=31 July 2020 }}</ref><ref name="NC-20200728">{{cite journal |author=Morono, Yuki |display-authors=et al. |title=Aerobic microbial life persists in oxic marine sediment as old as 101.5 million years |date=28 July 2020 |journal=[[Nature Communications]] |volume=11 |number=3626 |page=3626 |doi=10.1038/s41467-020-17330-1 |pmid=32724059 |pmc=7387439 |bibcode=2020NatCo..11.3626M }}</ref>

==Delayed resuscitation in humans==
This condition of apparent [[death]] or interruption of vital signs in humans may be similar to a medical interpretation of suspended animation. It is only possible to recover signs of life if the brain and other vital organs suffer no cell deterioration, necrosis or [[molecular death]] principally caused by oxygen deprivation or excess temperature (especially high temperature).<ref>{{cite journal|url=http://gradestack.com/Dr-Bhatia-Medical/Molecular-death-is-A/2-3042-3166-15605-sf| title=Molecular death is|publisher=Forensic Medicine_gradestack.com}}</ref>

Cases have been reported of individuals having returned from this apparent interruption of life lasting over one half hour, two hours, eight hours, or more (while adhering to these specific conditions for oxygen and temperature) have been analysed in depth, but these cases are considered rare and unusual phenomena. The brain begins to die after five minutes without oxygen; nervous tissues die intermediately when a "somatic death" occurs while muscles die over one to two hours following this last condition.<ref>{{cite journal|url=http://gradestack.com/Dr-Bhatia-Medical/Definition-of-suspended/19-3042-3166-15605-sf|title=Definition of suspended animation is|publisher=Forensic Medicine_gradestack.com|access-date=6 June 2017|archive-date=29 June 2018|archive-url=https://web.archive.org/web/20180629074224/https://gradestack.com/Dr-Bhatia-Medical/Definition-of-suspended/19-3042-3166-15605-sf|url-status=dead}}</ref>

It has been possible to obtain a successful resuscitation and recover life after apparent suspended animation in such instances as after anaesthesia, heat stroke, electrocution, narcotic poisoning, heart attack or cardiac arrest, shock, newborn infants, cerebral concussion, or cholera.

Supposedly, in suspended animation, a person technically would not die, as long as they were able to preserve the minimum conditions in an environment extremely close to death and return to a normal living state. An example of such a case is [[Anna Bågenholm]], a Swedish radiologist who allegedly survived 80 minutes under ice in a frozen lake in a state of [[cardiac arrest]] with no brain damage in 1999.<ref>{{cite news|url=https://www.independent.co.uk/news/world/americas/miracle-student-survived-his-body-being-frozen-solid-a6823801.html |archive-url=https://ghostarchive.org/archive/20220525/https://www.independent.co.uk/news/world/americas/miracle-student-survived-his-body-being-frozen-solid-a6823801.html |archive-date=25 May 2022 |url-access=subscription |url-status=live| title='Miracle' student survived his body being frozen solid|newspaper=independent.co.uk|date=20 January 2016|access-date=5 June 2017}}</ref><ref>{{cite journal |vauthors=Gilbert M, Busund R, Skagseth A, Nilsen P, Solbo J |year=2000 |title=Resuscitation from accidental hypothermia of 13.7°C with circulatory arrest |journal=[[The Lancet]] |volume=355 |pages=375–376 |doi=10.1016/S0140-6736(00)01021-7 |issue=9201|pmid=10665559 |s2cid=54348869 }}</ref>

Other cases of [[hypothermia]] where people survived without damage are:
* John Smith, a 14-year-old boy who survived 15{{nbs}}minutes under ice in a frozen lake before paramedics arrived to pull him onto dry land and saved him.<ref>[http://www.medicaldaily.com/pulse/suspended-animation-how-boy-survived-15-minutes-trapped-under-ice-frozen-lake-321206 Suspended Animation? How A Boy Survived 15 Minutes Trapped Under Ice In Frozen Lake] at Medical Daily</ref>
* Mitsutaka Uchikoshi, a Japanese man, was reported by media to have survived the cold for 24{{nbs}}days in 2006 without food or water when he purportedly fell into a state similar to hibernation. This was doubted by some medical experts, claiming that surviving such a prolonged period without fluids was physiologically impossible.<ref>[http://news.bbc.co.uk/2/hi/asia-pacific/6197339.stm Japanese man in mystery survival] at BBC News</ref>{{Better source needed|reason=This case, if true, would be very exceptional. As such, as per WP:EXCEPTIONAL it requires exceptional sources. A case report from the medical scientific literature is needed here.|date=November 2021}}
* Paulie Hynek, who, at age two, survived several hours of hypothermia-induced cardiac arrest and whose body temperature reached {{convert|18|C|F}}.<ref>[http://mayoclinichealthsystem.org/local-data/press-releases/eau-claire/mayo-clinic-launches-national-mobile-exhibit-tour ''Eleva boy's story part of national tour to honor Mayo Clinics 150 years''] {{webarchive|url=https://web.archive.org/web/20150511022742/http://mayoclinichealthsystem.org/local-data/press-releases/eau-claire/mayo-clinic-launches-national-mobile-exhibit-tour |date=11 May 2015 }} Mayo Clinic</ref>
* [[Erika Nordby]], a toddler who in 2001 was revived after two hours without apparent heartbeat with a body temperature of about {{convert|16|C|F}}.<ref name=warick>{{cite news|work=Edmonton Journal|author=Warick, Jason|date=23 February 2002|page=A3|title='Miracle child' bears few scars one year after brush with death}}</ref>

=== Human hibernation ===
{{Main|Therapeutic hypothermia}}

It has been suggested that bone lesions provide evidence of hibernation among the early human population whose remains have been retrieved at the [[Archaeological site of Atapuerca]]. In a paper published in the journal ''L'Anthropologie'', researchers [[Juan Luis Arsuaga|Juan-Luis Arsuaga]] and Antonis Bartsiokas point out that "primitive mammals and primates" like bush babies and lorises hibernate, which suggests that "the genetic basis and physiology for such a hypometabolism could be preserved in many mammalian species, including humans".<ref>{{Cite news |last=Sullivan |first=R |date=2020 |title=Early humans may have hibernated |url=https://www.independent.co.uk/news/science/archaeology/early-humans-hibernation-winter-atapuerca-spain-b1776824.html |url-access=subscription |url-status=live |archive-url=https://ghostarchive.org/archive/20220525/https://www.independent.co.uk/news/science/archaeology/early-humans-hibernation-winter-atapuerca-spain-b1776824.html |archive-date=25 May 2022 |access-date=25 November 2021}} This article refers to Bartsiokas, A. & Arsuaga, J. (2020). ''Hibernation in hominins from Atapuerca, Spain half a million years ago''. [[L'Anthropologie]], Volume 124, Issue 5</ref>

Since the 1970s, [[deep hypothermic circulatory arrest|induced hypothermia]] has been performed for some [[heart surgery|open-heart surgeries]] as an alternative to [[heart-lung machine]]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.

There are many research projects currently investigating how to achieve "induced [[hibernation]]" in humans.<ref>[http://www.livescience.com/health/050421_hibernation.html New Hibernation Technique might work on humans | LiveScience] at www.livescience.com</ref><ref>[https://web.archive.org/web/20080807172226/http://www.timesonline.co.uk/tol/news/uk/science/article1845294.ece Race to be first to 'hibernate' human beings - Times Online] at www.timesonline.co.uk</ref> 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.

The primary focus of research for human hibernation is to reach a state of [[torpor]], defined as a gradual physiological inhibition to reduce oxygen demand and obtain energy conservation by hypometabolic behaviors altering biochemical processes. In previous studies, it was demonstrated that physiological and biochemical events could inhibit endogenous thermoregulation before the onset of hypothermia in a challenging process known as "estivation". This is indispensable to survive harsh environmental conditions, as seen in some amphibians and reptiles.<ref>{{Cite journal |title=Is Human Hibernation Possible? |url=https://nature.berkeley.edu/garbelottoat/wp-content/uploads/lee2008-1.pdf |publisher=nature.berkeley.edu}}</ref>

== Scientific possibilities ==

=== Temperature-induced ===

Lowering the temperature of a substance reduces its chemical activity by the [[Arrhenius equation]]. This includes life processes such as metabolism. [[Cryonics]] could eventually provide long-term suspended animation.<ref name="Tandy C 2014">Tandy C (2014). The Prospect of Immortality − Fifty Years Later. Ria University Press, USA, {{ISBN|978-1-934297-21-6}}</ref>

==== Emergency Preservation and Resuscitation ====

[[Emergency Preservation and Resuscitation]] (EPR) is a way to slow the bodily processes that would lead to death in cases of severe injury.<ref name="Delbert-2019">{{Cite web|last=Delbert|first=Caroline|date=2019-11-20|title=Doctors Place Humans in True Suspended Animation for First Time|url=https://www.popularmechanics.com/science/health/a29860656/first-human-trial-suspended-animation/|access-date=2020-09-29|website=Popular Mechanics|language=en-US}}</ref>  This involves lowering the body's temperature below {{convert|34|C|F}}, which is the current standard for [[therapeutic hypothermia]].<ref name="Delbert-2019" />

====Hypothermic experiments on animals====

In June 2005, scientists at the [[University of Pittsburgh]]'s Safar Center for Resuscitation Research announced they had managed to place [[dog]]s in suspended animation and bring them back to life, most of them without [[brain damage]], by draining the [[blood]] out of the dogs' bodies and injecting a low temperature solution into their [[circulatory system]]s, which in turn keeps the bodies alive in stasis. After three hours of being [[clinically dead]], the dogs' blood was returned to their circulatory systems, and the animals were revived by delivering an [[electric shock]] to their hearts. The heart started pumping the blood around the body, and the dogs were brought back to life.<ref>{{cite news| url=https://www.nytimes.com/2005/12/11/magazine/11ideas_section4-21.html | work=The New York Times | first=Stephen | last=Mihm | title=Zombie Dogs | date=11 December 2005}}</ref>

On 20 January 2006, doctors from the [[Massachusetts General Hospital]] in [[Boston, Massachusetts|Boston]] announced they had placed [[pig]]s in suspended animation with a similar technique. The pigs were [[Anesthesia|anaesthetized]] and major blood loss was induced, along with simulated - via scalpel - severe injuries (e.g. a punctured aorta as might happen in a car accident or shooting). After the pigs lost about half their blood the remaining blood was replaced with a chilled saline solution. As the body temperature reached {{convert|10|°C}} the damaged blood vessels were repaired and the blood was returned.<ref>{{cite journal|title=Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage?|vauthors=Alam HB, Rhee P, Honma K, Chen H, Ayuste EC, Lin T, Toruno K, Mehrani T, Engel C, Chen Z |year=2006|issue=1|pmid=16456447 |doi=10.1097/01.ta.0000198469.95292.ec |volume=60 |journal=J Trauma |pages=134–146}}</ref> The method was tested 200 times with a 90% success rate.<ref>{{cite news|url=http://www.smh.com.au/articles/2006/01/20/1137553739997.html|title=Doctors claim suspended animation success|newspaper=The Sydney Morning Herald|date=20 January 2006|access-date=10 October 2006}}</ref>

=== Chemically induced ===

The laboratory of [[Mark Roth (scientist)|Mark Roth]] at the [[Fred Hutchinson Cancer Research Center]] and institutes such as [[Suspended Animation, Inc]] are trying to implement suspended animation as a medical procedure which involves the therapeutic induction to a complete and temporary systemic [[ischemia]], directed to obtain a state of tolerance for the protection-preservation of the entire organism, this during a circulatory collapse "only by a limited period of one hour". The purpose is to avoid a serious injury, risk of brain damage or death, until the patient reaches specialized attention.<ref>{{cite journal| title=Suspended animation for delayed resuscitation. Crit Care Med. 1996 Feb;24(2 Suppl):S24-47|journal=Critical Care Medicine|volume=24|issue=2 Suppl|pages=S24–47|pmid = 8608704|year = 1996|last1 = Bellamy|first1 = R|last2=Safar|first2=P|last3=Tisherman|first3=S. A|last4=Basford|first4=R|last5=Bruttig|first5=S. P|last6=Capone|first6=A|last7=Dubick|first7=M. A|last8=Ernster|first8=L|last9=Hattler Jr|first9=B. G|last10=Hochachka|first10=P|last11=Klain|first11=M|last12=Kochanek|first12=P. M|last13=Kofke|first13=W. A|last14=Lancaster|first14=J. R|last15=McGowan Jr|first15=F. X|last16=Oeltgen|first16=P. R|last17=Severinghaus|first17=J. W|last18=Taylor|first18=M. J|last19=Zar|first19=H|doi=10.1097/00003246-199602000-00046}}</ref>

== See also ==
{{col div|colwidth=30em}}
* [[Brain death]]
* [[Coma]]
* [[Cryptobiosis]]
* [[Immortality]]
* [[Life extension]]
* [[Stasis (fiction)|Stasis]]
* [[Suspended animation in fiction]]
* [[Technological utopianism]]
{{div col end}}

== References ==
{{Reflist|30em}}

{{Cryonics}}
{{emerging technologies|topics=yes|biomed=yes}}
{{Authority control}}

[[Category:Cryonics]]
[[Category:Senescence]]