Emergency Preservation and Resuscitation (EPR) is an experimental medical procedure where an emergency department patient is cooled into suspended animation for an hour to prevent incipient death from ischemia, such as the blood loss following a shooting or stabbing.
That page doesn’t say this is a net win or worked well at all, but it’s a difficult line of research. Not only are the first patients almost dead at the start of the process (as is always the case with high-risk of death experimental procedures), but there also is no way to know when a patient will show up.
Deep hypothermic circulatory arrest (DHCA) is a surgical technique that induces deep medical hypothermia. It involves cooling the body to temperatures between 20 °C (68 °F) to 25 °C (77 °F), and stopping blood circulation and brain function for up to one hour.
I think that’s a proven winner for some patients, but only at relatively high temperatures (“Profound hypothermia (< 14 °C) usually isn't used clinically. It is a subject of research in animals and human clinical trials”)
Besides the research discussed in the other comments we have now many documented cases of people falling into extremely cold water in the winter, being pulled out after an hour, and recovering. The warming has to be done properly though, if you just pull them out and heat them up immediately they'll die. If you just pull them out and let them warm up very slowly in a warm room they'll die. You have to heat them up as evenly as you can at a certain rate.
When you consider that oxygen deprivation is the primary cause of cell death it makes sense. Cooling down the cells greatly reduces their metabolism and thus oxygen requirements. But cooling the heart down before the brain just makes the brain run out of oxygen first. The more oxygen-dependent the organ the more critical it is that organ be cooled first. Conversely you can't warm up those organs before the heart and lungs or they'll survive that long time of cooling only to die during warming due to lack of oxygen.
Some people are documented as surviving in freezing temperatures for extended periods, yes.
This is what you would expect from freezing. It preserves things. The difficulty with freezing is getting back up to normal temperatures safely. (And the creation of ice crystals, which can be very damaging.)
I think it was tried with larger mammals and it didn't work, which is why the research for humans was dropped. The hope that at some point in the future it may be possible is the entire point of cryonics.
No idea, but another comment claims it works for severed body parts. I'd assume that freezing an attached bodypart would have complications due to circulation being hindered in non frozen parts of the body, and it would be painful.
Don't think a 21st century ethics board is gonna be onboard for doing such an experiment either.
people in siberia/artic regularly freeze their fingers, no need to have cobayes.
Blocking the circulation in the hand does not make someone die, many people survived loosing an arm for a reason.
What must be said though is that while freezing allow for partial body rescuscitation, let's not be fooled. The mice or body part might behave normally, but the body has suffered from a lot of possibly permanent damage (conformational changes, oxidative stress). I expect rescuscitated humans to have a lower quality of life and reduced lifespan, although that's fucking worth it for being rescuscitated!!
One reason is that ice has that annoying property of taking more volume than water. This has consequences. However modern cryogenics aims to vitrify water, which is a special kind of ice that does not take more space!
What people don't know is that structurally preserving organs AKA cryogenics, is a solved problem. Researchers have done that sucessfully to a pig's brain, preserving 100% of its structure. The current issue is that while we can preserve the body without structural losses, we don't know how to reanimate it because the chemicals they uses become toxic upon reanimation and there is no known way to extract it fast enough.
As a reminder, before rescuscitating humans, cryogenics will allow better preservation of blood and organ donations.
Not everything that works in a mouse model works in humans.