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Coma vs. Brain Dead - What's the difference?


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#1 ParanoiA

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Posted 8 November 2008 - 02:05 PM

Ok, so I was wondering what makes a coma different from being brain dead. I always thought brain death was just a poetic way to describe the condition of no brain activity - although I'm sure something is going on. And I thought a coma was the same thing, neurologically, except for the implication that the individual will eventually come out of it.

So what is exactly going on? How come we don't consider a coma to be temporary brain death?
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#2 insane_alien

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Posted 8 November 2008 - 02:23 PM

a coma is where the individual is in a prolonged unconcious state and does not respond to stimuli and may have lowered brain activity(but not zero activity).

brain death is when there is zero activity in the brain.

may be inaccurate as that was achieved from 2 googles over a period of 5 minutes,
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#3 ParanoiA

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Posted 8 November 2008 - 03:07 PM

Thanks. Yeah, see I did the google thing. But I was hoping for something a bit more detailed, or technical.

Also, how could there be zero activity in the brain? How do they breath?
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#4 Cap'n Refsmmat

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Posted 8 November 2008 - 03:39 PM

They don't. As far as I know, brain dead people are considered dead, because when you're brain-dead not even the involuntary things (like breathing) are occurring.
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#5 ParanoiA

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Posted 8 November 2008 - 04:13 PM

Well I'll be darned. So, I guess it's only their body that's living. Well that does seem to answer my question. Thanks fellas.
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#6 big314mp

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Posted 8 November 2008 - 06:52 PM

Sometimes brain death refers to death of higher brain functions: i.e. not the brain stem. So if the brain stem is still alive, then the person can still breath, digest, etc.

Usually this is called persistent vegetative state, though.
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#7 Durro

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Posted 21 March 2009 - 12:42 PM

Brain death means that the person cannot function without ventilation and other supportive mechanisms. Withdrawal of support will mean certain death and even with aggressive therapy, the profound brain damage and loss of function may mean that multisystem organ failure will lead to death anyhow.

There are a number of tests for brain death that can be performed to ensure that not even the most basic reflex functions are viable. Apart from an EEG that shows no brain function, some of the tests include taking the patient off mechanical ventilation to see if they breath spontaneously at all, sticking a tongue depressor down the throat of the patient to stimulate the gag reflex (or note that it's absent) and squirting ice cold water in the ear canal to stimulate the shiver reflex there. If these most basic functions are inoperative, there is no hope for recovery of the patient at all and they are for all purposes, brain dead.

These are the types of patients that are candidates for organ donation, before their uncontrollable blood pressure, temperature maintenance, and other autonomic nervous system functions go completely haywire leading to organ failure.

Incidentally, in case people don't realise, the reason that the heart beats on despite tremendous brain damage sometimes is that the cardiac pacemaker - the SA node - works largely independent of the nervous system.

By way of comparison, people who are in a "coma" are merely largely unresponsive and unconscious, but may have markedly varying degrees of brain function. Some will have reflexes, involuntary movements and of course, control of their blood pressure, digestion and temperature regulation. Some people in comas care able to hear and feel, but are unable to give responses to the effect that they are receiving input from the world around them. Comas may be reversible and the patient may emerge with some or all of their normal brain function, depending on what was the causative agent for their coma in the first place.

The layperson often confuses a coma with brain death, but in medical terms, they are markedly different entities.

Cheers,

Durro
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#8 needinganswers

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Posted 26 January 2010 - 09:39 AM

my partner was in a horrific accident, and the doctors told me he had no other injury other than that to his head. Unfortunately they told me he was brain dead and that he would die within minutes to maybe an hour of his life support being removed. However, he continued breathing for many many hours later, his temperature went back to normal, he kept moaning and groaning, his body kept twitching, and finally, we had to watch him drown in his own blood. are you telling me that he was only in a coma and that the doctor's were wrong?! Please tell me i did not watch and help the love of my life die when there was something i could have done?!
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#9 tomgwyther

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Posted 27 January 2010 - 12:03 AM

Incidentally, in case people don't realise, the reason that the heart beats on despite tremendous brain damage sometimes is that the cardiac pacemaker - the SA node - works largely independent of the nervous system.


Durro


other effects as well as heart beat can also be observed .
body temperature is regulated by the hypothalamus. Blood pressure and Breathing function can be maintained by the medulla oblongata; part of the medulla which is more akin to the spinal chord than the brain itself.

Edited by tomgwyther, 27 January 2010 - 12:28 AM.

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#10 needinganswers

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Posted 28 January 2010 - 02:35 AM

My partner was completely healthy, actually extremely healthy, young (23yrs) and very fit, other than the damage done to his brain on impact they said he would have walked away from the accident. What I really want to know for my own peice of mind is that, after they diagnosed him brain dead, and removed him from life support. They took him off morphine, and he returned to pretty much normal on his own. They told me he could feel no pain. All i want to know is that he truly felt no pain. The moans and groans he kept making, the twitches, the return of his normal body temp, and the continueing of his breathing functions on their own for hours after doesn't feel like brain death to me. Can someone who knows please just let me know where I stand. He had no pace maker or any artificial body parts or helping instruments. This is continued on from my previous statement above. I couldn't bare it if he was only in a coma and could feel all the pain of his accident.
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#11 Cap'n Refsmmat

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Posted 28 January 2010 - 02:42 AM

Depends. How did they arrive at the conclusion he was brain dead? It can often be very hard to tell, so they'd have to decide somehow.

It's possible that enough of the brain stem was functioning to perform minimal tasks like twitching and groaning. But it's impossible to tell what the rest of the brain was doing without an EEG or knowing just how damaged his brain was.
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#12 needinganswers

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Posted 28 January 2010 - 05:04 AM

They tried testing his eye's but they were unresponsive, they did a brain scan, but no eeg. They sent the scans away to outside nuerosurgions as we had none here, and later we were told there was not much hope. but they also said he was not able to breath on his own, and he may possibly be able to for 15mins maybe an hour at the most. They said he could feel no pain, and removed him from the morphine. also after his last breath, his body contorted and he nearly fitted himself of the bed. He went from unmoving to almost sitting straight up and off the bed on his own. If the brain stem was all that was left and causeing this, could he still have felt pain?
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#13 pywakit

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Posted 28 January 2010 - 06:16 AM

They tried testing his eye's but they were unresponsive, they did a brain scan, but no eeg. They sent the scans away to outside nuerosurgions as we had none here, and later we were told there was not much hope. but they also said he was not able to breath on his own, and he may possibly be able to for 15mins maybe an hour at the most. They said he could feel no pain, and removed him from the morphine. also after his last breath, his body contorted and he nearly fitted himself of the bed. He went from unmoving to almost sitting straight up and off the bed on his own. If the brain stem was all that was left and causeing this, could he still have felt pain?


I can't answer your question, but I am very sorry. The reality is that he may, or may not have felt pain. There is probabaly no way to know either way anymore.

Most certainly, his suffering is now past. And you are left behind to suffer the pain of loss. Having lost my son by drowning, I can tell you that I have spent decades coping with the certainty that he suffered greatly, and that he suffered, and he died alone.

Last Father's Day, my father finally drowned in his own fluids ... this after suffering a massive stroke one week prior. I spent the last 4 days holding his hand, and talking to him. The last 36 hours, he was gone from me, no longer responsive to questions. But he clearly was still suffering, even with massive doses of morphine. I can feel your helplessness. I'm so sorry.

But I took something good from this experience. Hard to believe, I suppose.

Please try to take comfort from having been there with your partner. He may have suffered, but you were there to hold his hand. I am willing to bet, that even in a coma, somewhere in his brain was the awareness that he was not alone.

You did all that was humanly possible at the time. Don't let yourself believe you could have done more. You couldn't.

I'm sure on some level, he was grateful. I know my Dad was.

Your pain will pass ... eventually. I hope it is soon. It sounds so pointless to repeat something you have already heard, but ....

He would not want you to suffer.

Best of luck to you.

James

#14 LimbicLoser

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Posted 29 January 2010 - 03:44 PM

Let me first also extend the human connection of empathy to you, needinganswers . . . though with soothing words of emotion, one can only help with the burden of carrying such weight, not relieve the weight, I do hope that by what I might say, or what pywakit has said, you can be help to look onward in time, along with any longing of the heart for a past.

Here, I think you can understand, we do not have enough information to make a really sure statement--as regards his specific condition. I do hope, nevertheless, that you will give a certain degree of fair consideration to the more thinkably so matters.

I assume that either a CT scan or an MRI had been done, and that sent off for interpretation. While we could presently keep the expression 'brain death' for the purpose of expediency, I would suggest care in using an expression such as 'brain dead.' Bernat [Bernat, 2009] offers 'death determined by brain criteria,' as a more accurate description of the circumstances, and I presently find no problem with that. We can take it from what you have provided, that we are looking at whole-brain death (and this is not to be confused with saying that the 'whole' of the brain is dead; there is a difference).

Taking it to be the case that somehow (and there are a great number of thinkable scenarios here) the brain stem was largely intact, we can understand how some basic autonomic functions would be fairly up and running. (This may bring back to mind the condition of 'Mike the headless chicken,' which walked around, ate, circulated blood, breathed, and so on...but all without consciousness of any degree.) Therefore, being able to breathe on his own may not have presented any major problem (other than evidence of lack of inspection time).

While motor 'automatisms' occur, it appears to be rare. What is called the 'Lazarus sign,' (bilateral arm elevation during apnoea testing) is seen at times too. That you have reported that he had otherwise been in very good health, the beside tests carry firm weight (other health problems could be ruled out for things like non-reflex for pupilary light/dark, or vestibulocular).

In that having been removed from ventilation, regardless of time involved, he did die, it is fair to understand that brain damage was irreversible. Additionally, this would be somewhat different than the circumstances of persistent vegetative state (PVS), locked-in syndrome [or state] (LIS), or cases of Guillain-barre syndrome (which are occasionally misdiagnosed as brain death cases). [Monti, et al.]

Now, to touch on one main concern which evidently has been weighing strongly on your heart; that of feeling pain. Again, while my heart goes out to you on this matter, I have at times seen what could be reasoned out to be too much emphasis put on the 'feeling pain matter in similar cases. Please rest assured, that the likelihood of there having been any pain felt (that is acknowledged cognitively) is very, very small. Especially, we can also consider, would this be the case if the major blow to the head had been more dorsal (upwards area) than frontal. At any rate, and given what you have told us, no, there had been no pain felt. Also, most tragically, he, the person, had been dead from relatively soon after the accident.




Bernat, James L (2009) Brain Death. The Neurology of Consciousness--Cognitive Neuroscience and Neurpathology, Laureys, Steven and Tononi, Giulio (eds); Academic Press, pp 151-162;

Monti, Martin M., et al. (2009) Neuroimaging and the Vegetative State--Resolving the Behavioral Assessment Dilemma? Disorders of
consciousness
, Ann. N.Y. Acad. Sci.
Vol 1157, pp 81~89;

Schiff, Nicholas D. (2009) Recovery of Consciousness after Brain Injury: An Integrative Research Paradigm for the Cognitive Neuroscience of Consciousness. The Cognitive Neurosciences 4th ed. Gazzaniga (ed), MIT Press; pp 1123~1136;

Schiff, Nicholas D. (2010) Recovery of consciousness after brain injury: a mesocircuit hypothesis. Trends Neursc., Vol 33, issue 1 (Jan); pp 1~9;

Bradley, Walter G. (2009) [i]Treating the Brain-What the Best Doctors Know
. Dana Press; pp 166~168;


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#15 Mr Skeptic

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Posted 30 January 2010 - 03:17 AM

I am sorry for your loss. I can only assume that the doctors knew what they were talking about. Only a small portion of the brain is needed for the autonomous functions. And even a corpse can twitch.

Might I suggest you consider, what would you like to be done to yourself should you end up in a similar situation? What would he have wanted? This may be a good time to consider writing a living will, and whether you want to donate organs. And let your loved ones know, so that they won't have to fret as much making those choices.
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#16 Genecks

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Posted 5 February 2010 - 04:43 PM

The concept and definition of death, according to medical science, can differ amongst people. There are many papers written about what exactly medical death is, and many people consider it death of the brain in relation to conscious beings. This would mean the person has lost function of the brain, can no longer being conscious and function (even if released from a coma), and so on. A person can argue a lot of different ways about death.

I would have the say brain death is massive brain degeneration along with the brain unable to undergo plastic recovery (neuroregeneration) to bring a person back to a state of homeostasis. I think a more modern definition will discuss something along the lines of plasticity and regeneration.

With a coma, the person more than likely hasn't undergone massive neural degeneration.

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#17 RoberN800

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Posted 22 November 2011 - 02:05 AM

my partner was in a horrific accident, and the doctors told me he had no other injury other than that to his head. Unfortunately they told me he was brain dead and that he would die within minutes to maybe an hour of his life support being removed. However, he continued breathing for many many hours later, his temperature went back to normal, he kept moaning and groaning, his body kept twitching, and finally, we had to watch him drown in his own blood. are you telling me that he was only in a coma and that the doctor's were wrong?! Please tell me i did not watch and help the love of my life die when there was something i could have done?!

So sorry for your loss, I can only say, when I was in a severe coma, I had no pain and no fear. And if you believe in his Spirit, I've read in many places, that it leaves the body before death.
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#18 KidSci

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Posted 9 November 2012 - 04:39 PM

I am Actually doing a paper on letting the people die after someone finding out that the body is brain dead. When you are brain dead, there is nothing that can be done to bring yo back. The only way the body even says alive is because of machines. And many people think that you should let the familys choose- i say no because it just takes an emotional toll, and the person is never coming back to life, so why prolong the inevitable?

Ok, so I was wondering what makes a coma different from being brain dead. I always thought brain death was just a poetic way to describe the condition of no brain activity - although I'm sure something is going on. And I thought a coma was the same thing, neurologically, except for the implication that the individual will eventually come out of it.

So what is exactly going on? How come we don't consider a coma to be temporary brain death?


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