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Artificial Heart Recipient Has No Pulse
laggist writes "A heart patient in Singapore has been implanted with an artificial heart that pumps blood continuously, allowing her to live without a pulse. From the article: '... the petite Madam Salina, who suffers from end-stage heart failure, would not have been able to use the older and bulkier models because they can only be implanted in patients 1.7m or taller. The 30-year-old administrative assistant is the first recipient here to get a new artificial heart that pumps blood continuously, the reason why there are no beats on her wrist.'"
The story is light on details, but an article from last year in MIT's Technology Review explains a bit more about how a pulse-less artificial heart works.
With hundreds of millions of years of evolution, are there any systems in the human body that are dependent on the pulse to function properly?
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The article doesn't address this, but I'm a little concerned by the idea of a pulseless system. On the one hand, there is no pressure spike, but on the other hand, the pressure never lets up. I'[m curious what effect this sort of device will have on strokes and other blood flow disturbances. The steady pulse-and-release rhythm constantly tugs at potential clots in different directions, presumably breaking up many incipient clots. Will a steady flow system do the same?
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Yeah, that was my first thought as well. It's very unlikely to actually happen in the real world. Still I recall a story from a while back where doctors were discussing the possibility of redefining "dead" from something like a 0.0001% recovery chance to 0.001% recovery chance. However, in the panic of a rush, I can believe a hurried doctor would fail to notice she's breathing.
Or misdiagnose her if she isn't.
How do you kill that which has no life?
I'm no med student. I'm just curious. I had heard that blood clotting relies on the blood remaining still for a period of time. Normally your pulse still allows for clotting because of the brief period of time that the blood doesn't flow. If you get a cut, you will bleed. In this case if the blood never stops moving will the individual bleed to death from something as simple as a papercut?
But at the same time, if that were the case how did the patient survive the surgery?
Or even more so, how do machines or the nurses/doctors see you're still living if you're temporary unconscious (maybe a few too many beers?) and your pulse is zero. Then they'll declare you dead and dig you to graveyard. Nice place to wake up after a night of partying.
Don't worry, the penguin's kernel has evolved to pulseless a few years ago and is all fine and dandy :P
I have discovered a truly marvelous proof of killer sig, which this margin is too narrow to contain.
Having always had a heartbeat since birth, I can only assume that I can feel it beat, but am ignoring it. Obviously there are exceptions where I can very much feel and hear my pulse, and am very well aware of it.
She'll never feel that again.
Does she notice?
Or even more so, how do machines or the nurses/doctors see you're still living if you're temporary unconscious (maybe a few too many beers?) and your pulse is zero.
Some kind of tattoo explaining the situation is probably in order.
In Vonda McIntyre's novel "Superluminal" starship pilots had to have their hearts replaced with a rotary pump because the rhythm of the heartbeat caused a breakdown in their bodies during FTL flight.
They called the pulse-less pilots "Aztecs".
Make you re-evaluate the standard by which we hold someone "living".
It's one thing if a person dies of natural old age, or at a terminal stage of progressive dementia, or simply due to brain injury -- the mind of the person, his character, his memory -- all is gone forever. There is no point in trying to keep the rest of the body alive (even though I'm sure some religious folks would disagree with this...)
It's completely another thing when someone dies of an organ failure that, by itself, doesn't destroy the person -- it just prevents functions necessary to sustain life further. The brain itself doesn't really need that much -- all it needs is a steady supply of fresh blood, containing the necessary nutrients, oxygen, and cellular content, at the correct temperature and pressure. But the body has to run a lot of different organs to keep that fresh blood coming.
Major organ failure (e.g. heart) was once considered synonymous with death. Now technology challenges that assumption. Sooner or later we will reach the day when either all organs (at least except the brain, although even that is questionable) will be viewed no differently than spare parts, replaceable at will when damaged. The human identity would be separated from the supporting organs, and considering a human dead just because his heart failed would be as ridiculous as considering the data on your computer gone just because the power supply failed. Yes, you can't access it without power, but all we need is some mechanisms from it being permanently lost every bloody time we turn off the power supply. In hard drives, this already works (nonvolatile storage). In humans, we'll find solutions to keep that blood coming to the brain, no matter what organ fails, and in a moment's notice. The only vulnerable body part would be the brain.
Of course, just like with a hard drive, we'll also sooner or later learn to back up brain data, which opens a whole new can of worms and completely re-defines our idea of life and humanity, but that's a story for another day.
Curious, honestly... I wonder what the long term ramifications of having a non-fluctuating bp are?
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It's good that these devices can now last years, but why wouldn't they keep the heart they take out, remove all the cells from the heart's tissue scaffold, and then regrow it with her own stem cells? They've already done this successfully in animals. One would assume that putting the original back in would be a better, and in the long run, cheaper option.
Even so, if there are other drunk people around who've watched a bit too many movies, she might get a stake through her "heart" or worse.
I think this solution is ingenious. However, I don't see this being as good as the real thing yet. I think the pumping of the blood is beneficial in flushing clogs out of arteries . Continuous blood might be more susceptible to build up. With that said this could drastically increase the life expectancy of the human race. I wonder whether artificially replacing organs is the next step forward. After all, isn't the brain the jewel that the organs protect?
Well, considering that my sister (she's a physician) tells me that life as a resident is a lot more like Scrubs and a lot less than ER, Grey's Anatomy, et. al., I am sure she would end up being the "newbie prank" for all new residents and nurses.
No sig for the moment.
Having pressure pulses should tend to make blood flow into places that are harder to get at. It's probably bad to operate continuously at high pressure, and it's probably bad not to go to high pressure. Like TFA says, further investigation into this type of pump is needed and planned if they can get funding. I just hope they don't test on some type population that happens to do well with it.
Most EMS systems and hospitals in her area will be notified, probably receive a packet of information on the device with instructions with what to do in an emergency. CPR and defibrillation will be withheld. With some devices (Left Ventricular Assistance Devices) you can shock the patient if they have one, but still no CPR. Since this is a pulseless machine, even doppler won't detect if the patient is alive (BP/pulse). However, you could probably auscultate and detect the wirring of the machine when listening for heart sounds.
-- Anonymous Paramedic Student
Actually many people thing the pumps damaging blood cells might cause a horrifying side effect of bypass surgery called 'pump head'
http://heartdisease.about.com/cs/bypasssurgery/a/pumphead.htm
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
I was looking for this comment as the tech is not new. I was surprised to see it now on Slashdot. Ventricular Assist Devices have been around for a long time, and I know that at least Thoratec's Heartmate II and Heartware's HVAD are continuous flow. At least 50 people in the US already have Heartware's device in them, and I think there's been a European study, too. One thing I've heard and would be curious to know if it's true, is that even though the device is a continuous flow pump many patients spontaneously develop a pulse anyway. Have you seen that?
I understand that life's not fair, just why is it never unfair in my favor?
And how would that be measured (non-invasively)? Blood pressure is read by squeezing off the artery and listening and watching for the various points in the pulse. If there is no pulse, there is no measurement.
Uh yeah there is. How do you think they get the low number in your blood pressure reading?
Here's how it works: They pump up the cuff until it blocks off all blood flow. They slowly lower the pressure until when the heart pumps, the pressure is enough to force it past the cuff and they can hear the pulse (and you can see the needle start to twitch on the pressure gauge). But at this point, the pressure is still enough to block blood flow during the 'off' half of the beat. So they continue lowering the pressure until they can hear that your blood is flowing continuously.
So to measure the blood pressure of someone without a pulse but whose blood is flowing, you do the exact same thing but skip the 'high' measurement. Easy-peasy.
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