Wikipedia

Suspended animation

For other uses, seeSuspended animation (disambiguation).

Suspended animationis the temporary (short- or long-term) 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 undergohibernation,and most plants have periods ofdormancy.This article focuses primarily on the potential of large animals, especially humans, to undergo suspended animation.

Cardiopulmonary resuscitation (CPR) being performed on a trauma patient in a hospital ofMaracay,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.

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 ofhibernation.When applied with therapeutic intent, as indeep hypothermic circulatory arrest(DHCA), usually technologically mediated revival is required.[1][2]

Basic principles

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Suspended animation is understood as the pausing oflife processesby external or internal means without terminatinglifeitself.[3]Breathing, heartbeat and other involuntary functions may still occur, but they can only be detected by artificial means.[4]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 contextshibernation,dormancyoranabiosis(the latter in some aquatic invertebrates and plants in scarcity conditions).

The revived microorganisms

In July 2020,marine biologistsreported thataerobicmicroorganisms(mainly), in "quasi-suspended animation", were found inorganically-poor sediments,up to 101.5 million years old, 68.9 metres (226 feet) below thesea floorin theSouth Pacific Gyre(SPG) ( "the deadest spot in the ocean" ), and could be thelongest-living life formsever found.[5][6]

Delayed resuscitation in humans

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This condition of apparentdeathor 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 ormolecular deathprincipally caused by oxygen deprivation or excess temperature (especially high temperature).[7]

Some examples of people that have returned from this apparent interruption of life lasting over half an hour, two hours, eight hours or more while adhering to these specific conditions for oxygen and temperature have been reported and 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.[8]

It has been possible to obtain a successful resuscitation and recover life in some instances, including 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 he or she 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 isAnna Bågenholm,a Swedish radiologist who allegedly survived 80 minutes under ice in a frozen lake in a state ofcardiac arrestwith no brain damage in 1999.[9][10]

Other cases ofhypothermiawhere people survived without damage are:

  • John Smith, a 14-year-old boy who survived 15 minutes under ice in a frozen lake before paramedics arrived to pull him onto dry land and saved him.[11]
  • Mitsutaka Uchikoshi, a Japanese man, was reported by media to have survived the cold for 24 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.[12][better source needed]
  • Paulie Hynek, who, at age two, survived several hours of hypothermia-induced cardiac arrest and whose body temperature reached 18 °C (64 °F).[13]
  • Erika Nordby,a toddler who in 2001 was revived after two hours without apparent heartbeat with a body temperature of about 16 °C (61 °F).[14]

Human hibernation

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Main article:Therapeutic hypothermia

It has been suggested that bone lesions provide evidence of hibernation among the early human population whose remains have been retrieved at theArchaeological site of Atapuerca.In a paper published in the journalL'Anthropologie,researchersJuan-Luis Arsuagaand 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".[15]

Since the 1970s,induced hypothermiahas been performed for someopen-heart surgeriesas an alternative toheart-lung machines.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 "inducedhibernation"in humans.[16][17]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 oftorpor,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.[18]

Scientific possibilities

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Temperature-induced

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Lowering the temperature of a substance reduces its chemical activity by theArrhenius equation.This includes life processes such as metabolism.Cryonicscould eventually provide long-term suspended animation.[19]

Emergency Preservation and Resuscitation

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Emergency Preservation and Resuscitation(EPR) is a way to slow the bodily processes that would lead to death in cases of severe injury.[20]This involves lowering the body's temperature below 34 °C (93 °F), which is the current standard fortherapeutic hypothermia.[20]

Hypothermic experiments on animals

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In June 2005, scientists at theUniversity of Pittsburgh's Safar Center for Resuscitation Research announced they had managed to placedogsin suspended animation and bring them back to life, most of them withoutbrain damage,by draining thebloodout of the dogs' bodies and injecting a low temperature solution into theircirculatory systems,which in turn keeps the bodies alive in stasis. After three hours of beingclinically dead,the dogs' blood was returned to their circulatory systems, and the animals were revived by delivering anelectric shockto their hearts. The heart started pumping the blood around the body, and the dogs were brought back to life.[21]

On 20 January 2006, doctors from theMassachusetts General HospitalinBostonannounced they had placedpigsin suspended animation with a similar technique. The pigs wereanaesthetizedand 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 10 °C (50 °F) the damaged blood vessels were repaired and the blood was returned.[22]The method was tested 200 times with a 90% success rate.[23]

Chemically induced

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The laboratory ofMark Rothat theFred Hutchinson Cancer Research Centerand institutes such asSuspended Animation, Incare trying to implement suspended animation as a medical procedure which involves the therapeutic induction to a complete and temporary systemicischemia,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.[24]

See also

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References

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  1. ^"Suspended Animation".Medical-Dictionary.thefreedictionary.
  2. ^Asfar, P; Calzia, E; Radermacher, P (2014)."Is pharmacological, H2S-induced 'suspended animation' feasible in the ICU?".Crit Care.18(2): 215.doi:10.1186/cc13782.PMC4060059.PMID25028804.
  3. ^Asfar, P. (2014)."Is pharmacological, H2S-induced 'suspended animation' feasible in the ICU?".Critical Care.182(2): 215.doi:10.1186/cc13782.PMC4060059.PMID25028804.
  4. ^"How do frogs survive winter? Why don't they freeze to death?".Scientific American.11 July 2014.Retrieved3 June2017.
  5. ^Wu, Katherine J. (28 July 2020)."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".The New York Times.Retrieved31 July2020.
  6. ^Morono, Yuki; et al. (28 July 2020)."Aerobic microbial life persists in oxic marine sediment as old as 101.5 million years".Nature Communications.11(3626): 3626.Bibcode:2020NatCo..11.3626M.doi:10.1038/s41467-020-17330-1.PMC7387439.PMID32724059.
  7. ^"Molecular death is".Forensic Medicine_gradestack.{{cite journal}}:Cite journal requires|journal=(help)
  8. ^"Definition of suspended animation is".Forensic Medicine_gradestack. Archived fromthe originalon 29 June 2018.Retrieved6 June2017.{{cite journal}}:Cite journal requires|journal=(help)
  9. ^"'Miracle' student survived his body being frozen solid ".independent.co.uk.20 January 2016.Archivedfrom the original on 25 May 2022.Retrieved5 June2017.
  10. ^Gilbert M, Busund R, Skagseth A, Nilsen P, Solbo J (2000). "Resuscitation from accidental hypothermia of 13.7°C with circulatory arrest".The Lancet.355(9201): 375–376.doi:10.1016/S0140-6736(00)01021-7.PMID10665559.S2CID54348869.
  11. ^Suspended Animation? How A Boy Survived 15 Minutes Trapped Under Ice In Frozen Lakeat Medical Daily
  12. ^Japanese man in mystery survivalat BBC News
  13. ^Eleva boy's story part of national tour to honor Mayo Clinics 150 yearsArchived11 May 2015 at theWayback MachineMayo Clinic
  14. ^Warick, Jason (23 February 2002). "'Miracle child' bears few scars one year after brush with death ".Edmonton Journal.p. A3.
  15. ^Sullivan, R (2020)."Early humans may have hibernated".Archivedfrom the original on 25 May 2022.Retrieved25 November2021.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
  16. ^New Hibernation Technique might work on humans | LiveScienceat livescience
  17. ^Race to be first to 'hibernate' human beings - Times Onlineat timesonline.co.uk
  18. ^"Is Human Hibernation Possible?"(PDF).nature.berkeley.edu.{{cite journal}}:Cite journal requires|journal=(help)
  19. ^Tandy C (2014). The Prospect of Immortality − Fifty Years Later. Ria University Press, USA,ISBN978-1-934297-21-6
  20. ^abDelbert, Caroline (20 November 2019)."Doctors Place Humans in True Suspended Animation for First Time".Popular Mechanics.Retrieved29 September2020.
  21. ^Mihm, Stephen (11 December 2005)."Zombie Dogs".The New York Times.
  22. ^Alam HB, Rhee P, Honma K, Chen H, Ayuste EC, Lin T, Toruno K, Mehrani T, Engel C, Chen Z (2006). "Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage?".J Trauma.60(1): 134–146.doi:10.1097/01.ta.0000198469.95292.ec.PMID16456447.
  23. ^"Doctors claim suspended animation success".The Sydney Morning Herald.20 January 2006.Retrieved10 October2006.
  24. ^Bellamy, R; Safar, P; Tisherman, S. A; Basford, R; Bruttig, S. P; Capone, A; Dubick, M. A; Ernster, L; Hattler Jr, B. G; Hochachka, P; Klain, M; Kochanek, P. M; Kofke, W. A; Lancaster, J. R; McGowan Jr, F. X; Oeltgen, P. R; Severinghaus, J. W; Taylor, M. J; Zar, H (1996). "Suspended animation for delayed resuscitation. Crit Care Med. 1996 Feb;24(2 Suppl):S24-47".Critical Care Medicine.24(2 Suppl): S24–47.doi:10.1097/00003246-199602000-00046.PMID8608704.
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