Is anyone aware of research into long-term comas as a potential alternative to cryonics? There are small numbers of examples of people in unresponsive comas for over a decade who then awake and are at least basically functional. It seems like it might be possible with perhaps cooling (lowering the body temperature to reduce metabolism and perhaps disease progression) with heart-lung machines to keep one's body alive for an indefinite period if normal life was otherwise about to end.
tl;dr, how long can people just stay on life support?
It seems far more likely to be revived from advanced life support than from cryonics. Given pain management (or even better highly-effetive consciousness suppression) it might be possible to preserve a living brain for many decades. It's obviously going to be quite a bit more expensive than liquid nitrogen, but potentially a batched setup (one large shared bloodstream for example) with a lot more subscribers could be cheaper than current cryonics.
Temporary theraputic hypothermia is very useful for treatment of cardiac arrest and other neurological insults, as it reduces reperfusion injury and the slower inflammatory brain damage that happens in the hours and days after a period of ischemia.
As for life support, people can live for decades on tube feeding and artificial ventilation, and years on chemical feed dripped into their blood (at the cost of liver function). That's just letting normal biology proceed though, substituting some of the functions of a fully functional nervous system or other org...
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