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fastspinecho t1_jd8ckeq wrote

First of all, there are two clinical definitions of death. The traditional definition is irreversible loss of blood circulation. The heart doesn't "decide" to do this, but due to some injury it can no longer pump blood. This means it can no longer deliver oxygen to the rest of the body, which means most of your organs can no longer produce sufficient energy to maintain homeostasis. Among other things, cells need to constantly use energy to pump water out of themselves. Without energy, they usually swell up and rupture. Again, this is not a "decision" or signal sent to the body, any more than a balloon decides to pop when punctured by a needle.

The second definition of death is "brain death". This means that brain cells are no longer receiving blood, and are all dying for the reasons given above. Other organs may still be receiving blood, but legally the person is still dead.


flyfruit__ t1_jd9gzwh wrote

So if someone is brain dead, it means their body could still function without knowing it? Say if, by absurd, that body can be hydrated and fed, can the rest of the body still be preserved?


Rebeccalon787 t1_jd9jymz wrote

Yes, witnessed it first hand. Was there to pull the life support because I was told they were dead. Took me talking to doctors for an explanation as to why they were vocalizing, of course just sounds, eyes open and moving, body twitching. Was hard in that moment to believe this person wasn't "alive". It took less than 20 mins after the life support was removed, so I know I made the right decision. Still tough to wrap your mind around it in the moment.


NecroAssssin t1_jdbu2ub wrote

Brains are just flat out weird. You ever read about the French Civil Servant that on autopsy, we're found to not have a brain at all? Just an imprint along the skull.


fastspinecho t1_jd9ioe5 wrote

Yes, the rest of the body could still function.

That said, it probably wouldn't function for that long. The brain has "autonomic" functions that help maintain proper blood pressure, etc. After it's gone, the body will eventually become hemodynamically unstable and cardiac failure is pretty much inevitable. I suppose some future medical advances might one day prevent that. But really, why bother?

In practice, brain death is legal death. Hospitals will not provide life support to a dead person, unless they are an organ donor. So once brain death is diagnosed, one way or another that person will soon be in the morgue.


flyfruit__ t1_jd9lblg wrote

Yeah, that is why I asked the question. It looks amazing to me that, if a person is brain dead, even if the brain is autonomic, the body's organs can still be preserved for as long as it can: I assume probably 3 days to one week max.


peg72 t1_jd9zatr wrote

A friend was brain dead and lived six days after life support was withdrawn. She was in her 30s and I’m still mad her mother said no to organ donation


rdrast t1_jdb2cel wrote

The body can go for years, if fed, and sometimes with pumped O2, even with no higher brain functions available.


Kalanthropos t1_jdbb7rn wrote

There's a fascinating (though sad) case of a boy who became brain dead after contracting viral meningitis. I remember reading about it in a bioethics class. He lived for another 20 years without anything resembling a brain.


zekromNLR t1_jdo3ngp wrote

For a certain definition of "living", at any rate. His body was kept functioning, but there wasn't really a person living in it anymore.


Kalanthropos t1_jdo4jwo wrote

That's the thing, it raises a lot of philosophical questions. How do we define "death" if we can maintain the unity and function of the organism by supplanting its systems? What is the appropriate use of this technology?


zekromNLR t1_jdop6ko wrote

True. My personal answer to this is that I consider a "person" to be the processes that occur in the brain from which consciousness arises via some mechanism that is not yet well-understood, with the body more or less just being a vessel for those processes to occur in and for the consciousness to interact with the world.

And so my personal opinion is that the only real use for keeping a braindead body alive would be to keep its organs viable until transplantation, but I do understand that that is probably an opinion that is quite far to the materialist side of things.


rdrast t1_jdb236e wrote

Yes, the autonomic system, keeping heart and lungs working can still keep running, even if the cerebral cortex is completely gone.

The autonomic system is deep in the brain, and is the ladt to go, normally.

ETA: at the point there is no higher brain function (stimulus to light, sound, pain) "You" are essentially dead, but the body can continue to function, since a basic thing is to keep going.

The autonomic systems really will keep going, provided oxygen and food.

Sometimes for years.


New_Leek_8268 t1_jdcj4hz wrote

Is there any case that someone woke up from that condition?


HalcyonDreams36 t1_jdcjdlb wrote

We call that "life support"... A vegetative state, where the body functions are fine but the brain activity is gone.

Typically, that's a temporary state, while they evaluate the possibility of a person waking up (are they brain dead, or potentially just comatose?), and if the former, give families time to make decisions, come to terms, say goodbye.