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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.
First pulse.
"Paramedics/Doctors: Do not write me off as dead. Try to resuscitate"
...but I definitely see the need for a special Medic Alert badge for this.
This probably wouldn't happen cause of medical history and all that jazz, but that aside, it'd be priceless to see a nurse unaware of the circumstance trying to take her pulse..
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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...now I only need to come up with the perfect crime that only a person with no pulse could get away with and I can cash-in on a screenplay for an episode of CSI.
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What are the drawbacks?
That when there's a bug, it's a Blue Screen of Death you wont be booting back from.
The easiest way of moving a fluid is with a fan. It's trivial to make an artificial heart that works like that, but it has a disadvantage; the fan blades damage the blood cells. A few devices that work like this have been around for a while for emergency use (e.g. if the heart stops in the middle of an operation), but they can't be used for more than a couple of days without killing the patient (having a few blood cells killed is generally better than having no blood flowing, so they're fine for short-term use). I don't know how they solved that problem for this machine.
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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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What are the drawbacks?
Welcome to the afterlife, Jean-Luc. You're dead.
I suspect the battery pack strapped to her side and the scars on her chest might give them a clue this is not a normal emergency call. Its not like a pace maker where its contained within the body completely. Now that I think of it pace makers would cause more issues and they have been around for a while.
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.
Wouldn't this cause problems with perfusion? As I understand it, the arteries absorb some of the force of the heart's contraction due to their elasticity, and reuse it when they contract in turn to send the blood to more distal points in the body. It's been suggested that increased arterial stiffness is associated with the development of cardiovascular disease, and it seems like this might cause a similar effect over time. If you're getting an artificial heart, perhaps this point is moot, and from the story, it sounds like she doesn't have a choice, but I wonder if it would be an issue.
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Don't worry, the penguin's kernel has evolved to pulseless a few years ago and is all fine and dandy :P
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You know,
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Automated external defibrillators, such as the Physio-Control LifePak 500, will only administer a shock if they detect a valid shockable rhythm, i.e. ventricular fibrillation. This AED will not shock anyone or anything that does not have that rhythm present.
Manual external defibrillators, such as the Physio-Control LifePak 12, which may only be used by EMT-I or EMT-P (Paramedics) in my home state, can be used to administer a shock regardless of the presence or absence of any cardiac rhythm. This requires a manual override, and from what I have seen, is used even less often than the precordial thump.
Welcome to the afterlife, Jean-Luc. You're dead.
No, I am not dead. Because I refuse to believe that the afterlife is run by you. The universe is not so badly designed.
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?
Oh wait, no she's not. She's fucking BREATHING.
You're all idiots to think doctors, nurses and paramedics can't see if a person is breathing or not.
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.
Well, for one thing, they haven't replaced her lungs with continuous, ehm, blood conditioner. :-)
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Artificial heart + partying? That's a bright idea. Almost as good as smoking through that little hole in your neck.
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".
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I shall now have to amend my requirements for women that I will have sex with.
Pulse now optional.
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some blood machines use a system where the tube holding the blood is squeezed repeatedly by a rotating disk (there are like pegs on the disk and as they pass over the tubing the squeeze it like you do with toothpaste.) Advantage I understand it is its sterile since no part of the motor or other components actually contact the blood. Not sure if its a similar system or not.
It's life, Jim, but not as we know it.
This device is bladeless. In fact, one of the major advantages of this artificial heart compared to the traditional ones, is that this damages less blood cells than all other artificial "pulsed" devices. It has other benefits, like smaller size and less energy consumption. Overall, it's a greatly improved system.
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***Well, for one, how do these people get their blood pressure measured?*** Good question. It would appear they don't -- at least not with a sphygmomanometer that depends on the Korotkoff sounds generated by cutting off pulsating blood flow. And they won't have a pulse either. Those characteristics would normally be symptomatic of being dead. Or maybe one can pump up the blood pressure cuff and listen for a single -- hopefully loud and distinct -- thunk when blood starts flowing. OTOH, not having a pulse or measurable blood pressure beats all hell out of having a pulse and not being functional. I can't imagine what they are going to put on her MedicAlert bracelet.
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Snipers have to concentrate to manage their heart rates and time their shots between beats. A little practice and we've now got the world's quickest shot at 1,000 meters.
A pair of Peristaltic pumps will create a continuous flow and function significantly similarly to an actual heart. Many heart-bypass machines are designed like this.
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She is holding a Heart Mate II pump...most of our patients get this model...and NONE have a regular pulse. Funny since this is just breaking news and St Lukes Heart Transplant do it day in and day out, for a loooong time.
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Curious, honestly... I wonder what the long term ramifications of having a non-fluctuating bp are?
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the technical term for those wondering (this is/. afterall) is paristaltic pump
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 more than that.. I want to see the eyes of the nurse that doesn't know her condition when she checks her blood pressure...
What are we going to do tonight Brain?
according to the MIT review article the continuous flow artificial harts are in fact turbomachines. If you have any details on the particular device used here, I'd be interested to read about it.
Almost as good as smoking through that little hole in your neck.
Oh damn! I thought that what it was for. A cigarette, after all, fits the hole perfectly.
I just made an appointment with my surgeon to have it fitted for cigars, too.
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 wonder what effect this would have on emotional response. There is growing evidence that there is a two-way feedback loop between subjective emotion and bodily affect. In other words, not only does being nervous cause your heartrate to increase, but an increased heartrate makes you feel more nervous. I would be very interesting to see if this pulse-less heart would result in flatter emotional responses.
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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?
Breathing. One of the checks is not just a pulse, but breathing as well.
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I would be partying all day and nights.
It is better to Rock n Roll all night, and party ev-er-y day.
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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.
According to the MIT write-up, you still have blood pressure. The device would pump more or less blood based on your body's need at the time. What you would NOT have is a systolic/diastolic reading. You'd have one pressure reading. No more 110/70 reading, perhaps a 85mmHg in its place.
So what does the call center script say?
"If the patient has turned Blue, have them reincarnate and hope that solves the problem."
"If patient is unable to reincarnate, please reintroduce the four noble truths and the eightfold path. Then re-attempt to reincarnate."
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My partner was an ICU nurse and used continuous flow VADs (Ventricular Assist Device) for years.
Here's an article from 2000: http://circ.ahajournals.org/cgi/content/abstract/circulationaha;101/4/356
There is some controversy about continuous flow, but the notion is that most of the body experiences nearly continuous flow, anyway.
Implanted continuous flow notes from April: http://www.ncbi.nlm.nih.gov/pubmed/19324130
And another from 2008 implying that pulseless does not matter:
http://www.ncbi.nlm.nih.gov/pubmed/18442710?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed
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.
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It might be bad. Or it might be better. Maybe your arteries are only flexible because your stupid heart can't provide a steady pressure, and you needed to have flexible blood vessels to help even out the dramatic change in pressures that could damage more sensitive tissues. Maybe plaque buildup is a result of the flexing, and would decreased if the arteries walls didn't contract and trap small bits of plaque. Maybe it is bad for artery health, but your brain and mussels function 47% better so you're willing to put up with it.
Since no one has lived very long on a continuous-flow heart I think any supposed side-effects (detrimental or otherwise) would just be wild speculation. In any case, given the much longer equipment lifetimes it seems like this technology is at least worth investigating; we're hoping to install it in people who would otherwise be dead, and there's a whole slew of detrimental side-effects that otherwise-dead people are willing to live with for the sake of not being dead.
Welcome to the afterlife, Jean-Luc. You're dead.
No, I am not dead. Because I refuse to believe that the afterlife is run by you. The universe is not so badly designed.
Blasphemy! I should... cast you out, or smite you, or something.
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What are the drawbacks?
Well, I'm going to have to relax my "anything with a pulse" criterion...
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Open one of your eyes and shine a light in it. If the pupil constricts, you're alive. Of course, if you have a condition that makes your pupils NOT constrict, you're in some deep trouble!
But these artificial hearts are NOT for permanent implantation, they're to keep you alive until a donor heart can be found. If you have an artificial heart you should NOT be drinking; you're WAY too ill.
My cousin contracted a virus of some sort in her heart, and had an artificial heart implanted for several months. She has a live, donated heart now.
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It works like your esophagus does when swallowing.
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
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Read "Superluminal", by Vonda McIntyre. It's a sci-fi story about a woman who gets a turbopump heart that doesn't beat -- not because she's sick, but because it's a necessary part of becoming a starship pilot. Romance and heartbreak ensue.
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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