But Dr Parnia said when a person is resuscitated they do not return with a ‘magical enhancement’ of their memories.
Dr Parnia told LiveScience:
“They’ll describe watching doctors and nurses working, they’ll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them. It [the time a patient is declared dead] is all based on the moment when the heart stops. Technically speaking, that’s how you get the time of death.”
Doctors pronounce the time of death when the heart stops and when this happens, brain function halts ‘almost instantly’, Dr Parnia added. But he claims that he brain’s cerebral cortex, known as the ‘thinking part’, also slows down and flatlines, but the brain cells can still be active hours after the heart stopped.
Performing CPR on someone whose heart has stopped will send around 50 per cent of what blood it needs to the brain, which Dr Parnia says is enough to kick-start its functions.
“If you manage to restart the heart, which is what CPR attempts to do, you’ll gradually start to get the brain functioning again. The longer you’re doing CPR, those brain cell death pathways are still happening — they’re just happening at a slightly slower rate. What tends to happen is that people who’ve had these very profound experiences may come back positively transformed. They become more altruistic, more engaged with helping others. They find a new meaning to life having had an encounter with death. But there isn’t like a sudden magical enhancement of their memories. That’s just Hollywood jazz.”
His study is examining what happens to the brain after a person goes into cardiac arrest and whether consciousness continues after death and for how long. The aim of the research is to improve the quality of resuscitation and prevent brain injuries while restarting the heart.