Cryonics is the process of vitrifying the body and brain at death, preserving as much of the fine tissue structure as possible to enable the possibility of future restoration to life. There's no fundamental barrier to achieving that revival other than the fact that the necessary technology doesn't yet exist, and subject to the continuation of storage facilities the vitrified cryopreservees can wait for that time to arrive. A small cryonics industry has existed for some four decades now, with the most established non-profit groups being Alcor and the Cryonics Institute in the US. Several hundred people are presently preserved. It is an undertaking with an unknown timeline and chance of success, but these are the best odds offered to those who will age to death prior to the development of rejuvenation treatments.
Like most popular press articles on cryonics, the piece quoted below confuses low-temperature vitrification with freezing. They are in fact two very different things with very different outcomes on tissue viability: vitrification minimizes ice crystal formation, for example, which is the cause of much of the damage to frozen tissues.
Cryopreservation is a darling of the futurist community. The general premise is simple: medicine is continually getting better. Those who die today could be cured tomorrow. Cryonics is a way to bridge the gap between today's medicine and tomorrow's. "We see it as an extension of emergency medicine. We're just taking over when today's medicine gives up on a patient. Think of it this way: 50 years ago if you were walking along the street and someone keeled over in front of you and stopped breathing you would have checked them out and said they were dead and disposed of them. Today we don't do that, instead we do CPR and all kinds of things. People we thought were dead 50 years ago we now know were not. Cryonics is the same thing, we just have to stop them from getting worse and let a more advanced technology in the future fix that problem."
Alcor's members come from all over the world. Ideally the company will have an idea of when their members are going to die. Alcor maintains a watch list of members in failing health, and when it seems as though the time has come they send what they call a "standby team" to do just that - stand by the person's bed until they die. "It could be hours, days, we've gone as long as three weeks on standby." Once the person in question is declared legally dead, the process of preserving them can begin, and it's an intense one. First, the standby team transfers the patient from the hospital bed into an ice bed and covers them with an icy slurry. Then Alcor uses a "heart-lung resuscitator" to get the blood moving through the body again. They then administer 16 different medications meant to protect the cells from deteriorating after death. Once the patient is iced up and medicated, they move them to a place for surgery.
The next step includes draining as much blood and bodily fluids as possible from the person, replacing them with a solution that won't form ice crystals - essentially the same kind of antifreeze solution used in organ preservation during transplants. Once the patient's veins are full of this antifreeze, Alcor can begin to cool them down by about one degree Celsius every hour, eventually bringing the body down to -196C after about two weeks. Eventually the body finds its final home for the foreseeable future: upside down in a freezer, often alongside three others.
Most members are somewhat squeamish about the actual process of cryopreservation - but they see it as a means to an end. "We don't want to be cryopreserved - we hate the idea in fact. The idea of sitting in a tank of liquid nitrogen not able to control our own destinies is not appealing. But it's a lot more appealing than the alternative, to be digested by worms or incinerated - that doesn't appeal to us at all."