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A man who ran out of air at the bottom of the ocean

bbc.com

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Re: A man who ran out of air at the bottom of the ocean

#61
post #27
post #4

>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?

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?

I think you mean cryonics, not cryogenics.

Re: A man who ran out of air at the bottom of the ocean

#62
post #37

Earlier quoted context omitted.

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.

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/small…

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

Re: A man who ran out of air at the bottom of the ocean

#63
post #5

Reminds me of the fantastic movie The Abyss (1)...vaguely recall a similar scene where there's N tanks of oxygen for N+1 people, so they submerge 1 of the crew to lower her (i think) metabolic rate. Curious why they don't have emergency unmanned drones with the crew or why they don't have emergency tanks at their work site (which he was able to get back to) (1) - Not sure how well it has aged ( https://en.wikipedia.o…

At least for recreational diving each diver has two regulators attached to their tank, so if you have N tanks you can provide breathing gas to 2N people.

The movie involves hard dive suits, not SCUBA regulators. But you'd think there'd be an extra emergency regulator hanging off the tank...

Re: A man who ran out of air at the bottom of the ocean

#64
post #37

Earlier quoted context omitted.

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.

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…

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.

Re: A man who ran out of air at the bottom of the ocean

#65
post #64

Earlier quoted context omitted.

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…

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.

You have perfect knowledge of future technologies?

Re: A man who ran out of air at the bottom of the ocean

#66
post #64

Earlier quoted context omitted.

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…

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.

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.

Re: A man who ran out of air at the bottom of the ocean

#67
post #27

Earlier quoted context omitted.

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?

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 f…

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

Re: A man who ran out of air at the bottom of the ocean

#68
post #56
post #45

Earlier quoted context omitted.

We still cannot repair a spinal cord injury. A complete decapitation is a total spinal cord transection and more.

Head transplants have been carried out on mammals successfully in the past. The success criteria isn't in restoring limb function, but rather in keeping the brain alive on a host body. One problem at a time.

source? I read on this subject about monkey experiments and it seems the results were far from 'successful'.

Re: A man who ran out of air at the bottom of the ocean

#69
post #4

>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?

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...

Re: A man who ran out of air at the bottom of the ocean

#70
post #4

>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?

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