This document is written to be understandable without prior knowledge, though some technical terms are used. If anything is unclear, reach out at any time and we are happy to help.
If you would like to understand the procedures and risks in more detail, including the biological and biochemical basis, we can provide a comprehensive write-up. Just contact us.
Informed consent matters a great deal in human cryopreservation. People who sign up should have a good understanding of what they are, and are not, signing up for. Because successful revival of cryopreserved people depends on significant scientific advances, no guarantees can be made about whether or in what state patients would be revived.
Our policy is to always cryopreserve patients with the best technique available, unless it is physically impossible, for example a body lost at sea. We cannot know how far future technology will advance or what damage may be repairable, so we do not make arbitrary determinations about which patient conditions are good enough for future revival. Patients should still be aware of the damage that can occur before or during cryopreservation, and how that could affect a potential revival.
Currently it is not possible to warm up and revive cryopreserved humans. It is not known if and when the required technology will exist: it might take decades, centuries, or longer. It is entirely possible that revival will never be possible. No one, including us, can predict what the far future will allow, and we cannot give probabilities for the chances of revival, because they are unknown.
Cryopreservation involves several steps, each requiring its own procedures, including surgical ones.
The organisation or one of its partners may adapt the procedure, or use a fundamentally different one, if this is believed to increase the chances of future revival. This can follow from the individual situation or from new research findings. The preamble of the cryopreservation contract should be considered the shared understanding of why cryopreservation is done.
Pre-mortem injury. Conditions outside the control of the patient and of Tomorrow.bio can damage the body before cryopreservation. Damage to the brain may result from neurodegenerative disease, cancers, or accidents. Injuries sustained before cryopreservation may be irreversible.
Ischemic injury. Cryopreservation can only begin after a patient has been legally pronounced dead. In practice many patients go through a period in which the body is not sufficiently supplied with oxygen, which damages most organs, including the brain. This period can last minutes or hours, or longer depending on the circumstances. If these changes occur to a relevant degree, the cryoprotective agent cannot reach all of the tissue, which results in a lower quality preservation. It is not known whether this damage can be repaired in the future.
Cryoprotectant perfusion. Cryoprotectants must be delivered to the brain and other organs in high concentrations to limit ice formation. This takes considerable time and puts stress on the organs, tissues and brain: toxicity, vessel damage from pressure, and damage from high solute concentration can all occur. Perfusion is nevertheless necessary, because ice crystals damage cellular structure considerably. Other kinds of damage may also occur at this step, and it is unknown whether they can be repaired.
Biochemical and biophysical freezing. The goal of perfusion is to reach concentrations high enough to reduce or eliminate ice crystal formation. Depending on how much water is removed or replaced, some or all tissues may still freeze during cooling. The combination of elevated cryoprotectant concentration, cellular shrinkage and low temperature may damage cells, tissues and organs, including the brain. It is unknown whether this damage can be repaired.
Mechanical injury. Tissues dehydrate during the procedure and shrink as their water content falls. This shrinking can twist and deform tissue, damaging cells, axons, blood vessels and other structures. If parts of the body or brain cool at different speeds, thermal stress can cause fractures. It is unknown whether this damage can be repaired.
Unknown damage and incomplete technique. Because it is not fully known how memory, personality and consciousness arise, it is possible that the preservation technique does not preserve everything needed to revive the person. Unknown types of damage may also occur at any step.
Patients revived after cryopreservation could face problems arising from the condition that killed them, the dying process, the revival procedure itself, and reintegration into society. Physical issues could include complete or partial memory loss, loss of skills, and loss of part or all of the original biological body. Emotional issues could include loneliness and grief at the permanent loss of friends and family who were not cryopreserved, distress at the loss of work or social status, and difficulty adjusting to new cultural and social circumstances. Other problems could arise, and it is unknown whether they will be resolved in the future.
Independent of a patient’s condition, the chance of being revived could be threatened by external forces. We do everything possible to mitigate these risks, but it is possible that they are out of our control.
Economic and institutional. Large financial crises could push the cost of maintaining patients beyond what the patient care fund can pay, whether through the rising price of materials such as liquid nitrogen or through inflation eroding the fund. The organisation responsible could also cease operations without the possibility of transferring patients elsewhere.
Legal. Local or international bans on maintaining cryopreserved patients could force patients to be removed from their dewars. Relatives with significant resources could also attempt, and potentially succeed, to have a patient taken out of cryopreservation against that patient’s wishes.
Geopolitical. Changes in the geopolitics of the storage location could threaten patients. Borders could shift so that existing legal protections disappear, and war could make a storage location unsafe for patients and for the people maintaining them.
Existential threats. Existential threats could wipe out cryopreserved patients, or everyone able to care for them. These include, but are not limited to, asteroids, nuclear war, climate and natural disasters, and epidemics.
