The Past and Future of Cryonics
Cryopreservation refers to the process of freezing cells and tissues at very low temperatures to keep them from decay. The procedure, which has been used since the 1950s, was perfected over time and is now being used for various medical purposes, from assisted reproduction techniques to stem cell therapy. However, many scientists have been working towards a more ambitious goal, which is that of cryonics, a process of cryopreserving entire human bodies and being able to revive them one day.
The first attempts to cryopreserve entire human bodies were made in the 1960s, and the first human to be cryopreserved in hopes of a future revival was James Bedford, an American psychology professor whose body was frozen soon after his death in 1967. Ever since, researchers have drawn on advancements in cryobiology to improve the procedure, and many more human bodies have been cryopreserved. Cryobiology is the study of biological systems subjected to temperature blow their normal range,
As of 2021, it is not possible to revive someone who has been cryopreserved. The hope is that the advancement of medicine will one day make this possible. And while many argue that it is unlikely that this will ever become a reality, others believe that new technology will make it possible decades from now. Just like resuscitating someone whose heart has stopped was believed to be impossible until 1956 when cardiopulmonary resuscitation was invented, reviving a human that has been frozen could one day become possible.
The cryonics procedure takes place soon after the person is declared “legally” dead. For cryonics, legal death corresponds to clinical death, not brain death. The former occurs when the heart stops beating, leading to the ceasing of blood circulation and oxygenation. From the moment of clinical death, the cells in the body start decaying due to ischemic injury typically resulting from the absence of blood flow. However, brain activity does not stop with clinical death. In fact, it has been found that it actually continues for several hours, if not days, after clinical death.
Cryopreservation, then, must take place when a person’s heart has stopped beating but cannot be done if a person has been declared brain dead. This is because the whole purpose of cryonics is to preserve the brain structures and memory for a possible future revival. The body is then packed in ice, and an anticoagulant is injected to prevent the blood from clotting. To prevent the water inside cells from freezing, the blood is removed and replaced with a cryoprotectant that prevents damage caused by freezing. The body is cooled and stored in a metal tank filled with liquid nitrogen at a temperature of -196°C until it can be revived.
While cryonics is a controversial technique, it is performed with the hope that both science and medical technology will continue evolving to a point where the concept of death as we see it today will be revised. The patients that have been cryopreserved will have a chance of being restored to good health.
