Clinical death

Clinical death is cessation of blood circulation and breathing. It occurs when the heart stops beating in a regular rhythm, a condition called cardiac arrest. In cryonics, clinically dead patients must be declared legally dead before stabilization and cryopreservation can begin.

Stopped blood circulation has historically proven irreversible in most cases. Prior to the invention of cardiopulmonary resuscitation (CPR), defibrillation, epinephrine injection, and other treatments in the 20th century, the absence of blood circulation (and vital functions related to blood circulation) was historically considered the official definition of death. With the advent of these strategies, cardiac arrest came to be called clinical death rather than simply death, to reflect the possibility of post-arrest resuscitation. The definition of death depends on the current level of resuscitation or revival technologies.

During clinical death, all tissues and organs in the body steadily accumulate a type of injury called ischemic injury.