cryonics
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Introduction
- cryonics is the low-temperature preservation of legally dead individuals at the temperature of liquid nitrogen, with the speculative hope that future medical technology will be able to revive them & restore their health.[1][2]
- either whole bodies or brains may be cryopreserved
- cryonics is distinct from established medical cryopreservation techniques used for cells, tissues, & embryos[1][2]
Procedure
cool down
- the cryopreservation procedure typically involves perfusion of the body or brain with cryoprotective agents (such as dimethyl sulfoxide & glycerol) after legal death to prevent ice crystal formation, followed by cooling to cryogenic temperatures (around -196 C).[3]
- vitrification allows brain tissue to be cooled without ice formation to minimize structural damage.[4]
- ideally, cryonics procedures can begin within minutes of clinical death
- longer delays may still be compatible with the goal of future revival[4]
revival
- there is no current technology capable of revitalizing the body after the freezing process[1][5]
- the rationale is based on the premise that if future medicine can reverse complex aging- & disease-related changes that resulted in death, it might time to consider revitalizing the person
- the other challenge is how to mitigate &/or reverse damage from stopped blood flow & the cryopreservation procedure itself[4]
- neuronal death from ischemia may take hours rather than minutes
- this opens the theoretical window of opportunity for preservation[4][6]
- neuronal death from ischemia may take hours rather than minutes
Management
- a cryopreserved body or brain is maintained immersed in liquid nitrogen until which time it seems likely that the person can be revived & his or her medical issues at the time of death can be resolved.
More general terms
Additional terms
References
- ↑ 1.0 1.1 1.2 1.3 Moen OM. The case for cryonics. J Med Ethics. 2015 Aug;41(8):677-81. PMID: https://pubmed.ncbi.nlm.nih.gov/25717141 Review.
- ↑ 2.0 2.1 2.2 Hillenbrink R, Wareham CS. Mourning the frozen: considering the relational implications of cryonics. J Med Ethics. 2024 May 22;50(6):388-391. PMID: https://pubmed.ncbi.nlm.nih.gov/37451855
- ↑ 3.0 3.1 Canatelli-Mallat M, Lascaray F, Entraigues-Abramson M, et al Cryopreservation of a Human Brain and Its Experimental Correlate in Rats. Rejuvenation Res. 2020 Dec;23(6):516-525. PMID: https://pubmed.ncbi.nlm.nih.gov/32340558
- ↑ 4.0 4.1 4.2 4.3 4.4 Best BP. Scientific justification of cryonics practice. Rejuvenation Res. 2008 Apr;11(2):493-503. doi:http://dx.doi.org/ 10.1089/rej.2008.0661. PMID: https://pubmed.ncbi.nlm.nih.gov/18321197 Free PMC article. Review. https://pmc.ncbi.nlm.nih.gov/articles/PMC4733321/
- ↑ 5.0 5.1 Merkle RC. The technical feasibility of cryonics. Med Hypotheses. 1992 Sep;39(1):6-16. . PMID: https://pubmed.ncbi.nlm.nih.gov/1435395
- ↑ 6.0 6.1 Gillett CR, Brame T, Kendiorra EF. Comprehensive survey of United States internet users' sentiments towards cryopreservation. PLoS One. 2021 Jan 7;16(1):e0244980. PMID: https://pubmed.ncbi.nlm.nih.gov/33411839 PMCID: PMC7790260 Free PMC article. https://pmc.ncbi.nlm.nih.gov/articles/PMC7790260/