A CNN report on Friday explains the process of cryopreservation.

The process, the American cable network said, is one by which any living cells, tissues, organs or entire bodies are protected from decay by storing them at extremely low temperatures.

“The idea is to preserve them for indefinite periods until the rest of science has caught up and technology is available to revive them, bring them back to life and maybe cure the condition that killed them in the first place. Such technology, however, does not yet exist.”

CNN reported the Cryonics Institute, an American organisation that offers the service, as saying that the fundamental goal is “to give people a second chance at life” and extend human lifespans.

However, theCNN report stated that scientists who work with cryopreservation on smaller scales for research purposes are sceptical.

“It is currently science fiction to suggest that a person could be brought back to life in the future even considering technological advances,” CNN quoted Dr Channa Jayasena, clinical senior lecturer in reproductive endocrinology at Imperial College London. “Cryonics has risks for the patient, poses ethical issues for society, is highly expensive, but has no proven benefit. If this was a drug, it would never get approved.”

The CNN report then set out how the process works

“The process involves three key steps once someone has been declared legally dead, according to the Cryonics Institute.

“First, the body is immediately placed in an ice bath. At the same time, a ventilation mask is used to continue providing oxygen to the body’s organs – particularly the brain – and the anticoagulant heparin and automated CPR are used to maintain blood flow. Body temperature is monitored to ensure a gradual reduction.

“Next, the body is ‘vitrified’, meaning its cells and organs are prepared for the ultra-low temperatures they will soon experience. This involves replacing the body’s fluids with injected cryoprotective agents that act as an antifreeze, protecting the body from the damage of becoming frozen.

“Now that the body is prepped for the cold, the process of controlled cooling begins. This is the final step before long-term storage and involves slowly cooling the body further.

“The body is placed inside a protective insulating bag and then inside a cooling box where liquid nitrogen is fed in at a steady rate. This takes place slowly, over several days, until the body reaches a temperature of minus-200 degrees Celsius.”

The CNN report said that “those offering the service stress the slow and steady rate of the entire process, to ensure the least risk of damage to a person’s body”.

It added: “Either before or after the second stage, bodies may be transported to the nearest storage facility to complete the process. Once ready for storage, the body is put inside a liquid nitrogen vessel known as a cryostat. The vessels are not powered by electricity, so they are not affected by power outages.”