Duing the procedure blood is replaced with saline solution at a few degrees above zero. The dogs' body temperature drops to only 7C, compared with the usual 37C, inducing a state of hypothermia before death.
Although the animals are clinically dead, their tissues and organs are perfectly preserved.
Damaged blood vessels and tissues can then be repaired via surgery. The dogs are brought back to life by returning the blood to their bodies,giving them 100 per cent oxygen and applying electric shocks to restart their hearts.