"Throughout the programme there is considerable confusion about death, near death, and anaesthesia. Patients are often described as being “clinically dead” and then recovering. This is to misunderstand the definition of death. An important criterion in the certification of death is the irrecoverable cessation of brain function. This definition precludes anaesthesia as clinical death since the brain is fully oxygenated with a normal blood flow and recovery occurs without brain damage; indeed, this definition of death precludes anyone who subsequently recovers."
Is there any case in which the brain function was completely stopped and then it came back to life? I do not think so.