[ayakura]

>If you lower the brain temperature down to 30C (86F), it can increase the survival time from 10 to 20 minutes. If you cool the brain to 20C (68F), you can get an hour.

Wow, I actually didn't know this until now. Is this method used anywhere in medical procedures to resuscitate or prolong life?

[duskwuff]

It absolutely is. There's been considerable research on the use of therapeutic hypothermia during surgery, or after a traumatic injury.

https://en.wikipedia.org/wiki/Targeted_temperature_managemen...

https://en.wikipedia.org/wiki/Deep_hypothermic_circulatory_a...

[Someone]

The popularized way to say that is ”Nobody is dead until warm and dead”

See for example https://www.ncbi.nlm.nih.gov/pubmed/24882104, which states ”the longest time from cardiac arrest to return of spontaneous circulation was 6 h and 52 min”

[eecc]

About 30 years ago, my grandma had her entire aortic arch and then some more of the aorta itself replaced in a daring procedure. (I guess one can still call it as such today).

Notably, her body was cooled down significantly to reduce her metabolic rate down to nothing.

She survived several years, although she never quite recovered fully after that...

[Waterluvian]

"You're not dead until you're warm and dead." Is a quote that stuck with me. I was reading an article [1] about a person who froze to death and made a practically complete recovery.

By the way this story is a must read.

[1]https://www.thestar.com/news/insight/2017/02/19/this-queens-...

[tapland]

About 10 years ago, finishing up High School, I had work practice at a company developing a product that would cool the brain without cooling the rest of the body.

I think they had mixed results, and I haven't seen them or their competitors launch their products.

It works though, but it seems very difficult to cool the brain without chilling the whole body.

[thrower123]

I believe that this is a common trope in medical dramas. While I'm unaware of how often it is actually done, I know that I have seen it done in multiple episodes of House, or ER, etc, etc.

[cstrat]

At least it's an accurate medical trope :)

[sytelus]

So this may be the basis of cryogenics? If you just cool down in specific way, you can turn off metabolism and then turn back on again at later date?

[nradov]

Well not really. Cooling the patient down will give you a few hours at most under ideal conditions. Metabolism isn't turned off, just slowed down. If you freeze the patient the ice crystals damage the cells so much that revival becomes impossible.

[the_pwner224]

Flash freezing (using liquid nitrogen to freeze something really quickly) is used successfully for smaller objects, such as frozen berries and frozen vegetables that you can buy at the grocery store. The Wikipedia page on flash freezing links to this [0] site with some more discussion. The Wiki page also says that flash freezing still can take a few hours, so there are still ice crystals created, but a lot less/smaller than if you just put it in the freezer.

Overall it seems it's just a matter of waiting for technology to advance to the point where we can very move a 150 pound 2-meter-tall 1-foot-deep object from 98 degrees to 30 degrees, and at that point the science fiction will become reality.

[0]: https://web.archive.org/web/20120111233417/http://www.biotec...

[simcop2387]

The size matters significantly for this. Much larger and it becomes difficult to remove the heat throughout fast enough to do a flash freeze.

[bduerst]

This is correct. Flash freezing an entire human body consistently would be incredibly difficult.

[ChrisRR]

Even speaking as a brit, your mixture of metric and imperial and metric fascinates me.

I personally would've written 150lb, 6'6 tall, 1ft deep, 37 to 0 degrees

[OJFord]

150lb? That always strikes me as distinctly American, as opposed to 10st 10lb.

[saalweachter]

I'm so glad America got away before y'all went stone-crazy.

Redefining the hundredweight, seriously?

[ChrisRR]

Oops yes, I would actually have said 10 stone 10. I just copied the comment text because I was focusing on the 2 meters

[Zenbit_UX]

Tell tale sign of a Canadian.

[garmaine]

Cryonics involves vitrification, not freezing. Ice crystals do no damage if they never form in the first place.

Now the method of achieving vitrification involves pumping the body full of toxic antifreeze. But in principle it's easier to flush the antifreeze out when warming than to reverse ice crystal damage, though the techniques have not yet been worked out.

Thankfully it's not necessary for the reversal procedure to exist now for cryonics to be successfully used in preservation for the future.

[nradov]

There is zero chance that a human pumped full of antifreeze today will ever be successfully revised. Cryonics is a total scam by hucksters preying on desperate idiots.

And don't bother telling me that it's worth doing if there's even a tiny chance. The chance is exactly 0, and those resources are better spent on the living.

[ekianjo]

You can basically say that anyone living 500 years ago would say "there is zero chance" that what we take for granted today exists at all. Look at the technological achievements of even the past 50 years, most of it could hardly be predicted.

[ohazi]

There's a pretty big difference between the statements:

"We are likely to have life extending and resuscitation technologies in 500 years that are better than what we have today."

and

"The dead rich people in these particular vats of antifreeze have any more than a snowball's chance in hell at being successfully resuscitated."

I think the parent's analysis is correct. Your statements, while also correct, don't really refute the issues pointed out by the parent.

[bduerst]

By this logic, we don't even need to freeze the body. Simply opt in to being resimulated later, since the technology will exist "some day".

[tim333]

A zero chance is your opinion. I'd estimate there is a high change some of them will come back in some form. I'm more a believer in extracting information to an AI simulation than reanimating the old bodies.

[garmaine]

You have perfect knowledge of future technologies?

[brokenkebab]

Doesn't it sound similar to "Prove that I cannot win a billion!" from someone who spends money in casino?

[nwatson]

Also, frozen oblivion is better than being brought back by those who will not honor your motivations for being frozen. If it's possible to be brought back, organ-harvesting, post-cryo-slavery, medical-experiment-subject are the likely outcomes.

[Robotbeat]

Not for cryogenics, unfortunately, but yes for hibernation. NASA has funded the study of medically induced torpor for hibernating humans for deep space exploration: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201800...

If we ever do crewed interstellar travel, even if we can get the trip time down to 50 years or so, we’ll probably want something like this. But it’s useful even for Mars trips since you can fit a LOT more people in the same space.

[justinclift]

Interesting. That PDF doesn't seem to include increased radiation exposure while having a slowed ability to repair the damage.

Wonder if that's just because it's not viewed as important?

[Robotbeat]

There may be less oxidative stress as well, so it’s tough to say what wins out. Anyway, there are methods of providing radiation shielding to occupants as well.

[ekianjo]

Would you need to feed nutrients people during hibernation or is that a state of extrenely low metabolism?

[Robotbeat]

It’s answered in the PDF. There’s nutrient delivery, but metabolic rate is halved so there’s less required.

[garmaine]

I think you mean cryonics, not cryogenics.

[kzrdude]

Sure, there is research in applying this to premature babies in some cases