Admittedly I didn't read the whole story, the click-bait title got me.
I had a girlfriend with a similar device attached to her (an LVAD). At first it was a little unnerving seeing her unplug the batteries that were keeping her alive and charge them every night. It quickly became normal for me. Life with it seemed relatively normal except she had to have a purse with her at all times (it carried the batteries).
The interesting part was when she received a transplant and went cordless. After being attached to it for two years and not having a heartbeat the sound of her heat beating kept her up at night for a couple of weeks. I hadn't even considered the beating of a heart to be relevant to our daily lives until she had mentioned it once she heard hers beating again (an LVAD is just a constant velocity pump. The blood is always flowing).
Not sure how much it really adds to the conversation other than an interesting anecdote.
Wow, I had no idea you have no pulse when you have an LVAD. That's really neat.
Do you have any idea if there have ever been studies on the effect of constant flow vs peristaltic flow on the circulatory system? I wonder if the constant flow creates or solves any issues.
That continuous flow is new(-ish). My father had an LVAD in 2002, and it was the older type that actually pumps rhythmically, so that was his pulse. At the time continuous-flow models were in research, and I do remember there were concerns with thrombosis (basically, the shifting force of the pulse helps break up clots).
I don't know the current state of the art, but there are definitely studies (the keyword is "pulsatile"). For example:
For comparison, here's a picture of some LVADs. The one I've seen in person (after it had been taken back out!) is the one on the far left. Flow issues aside, I can imagine the smaller ones are easier on the patient in general, just from the perspective of surgery trauma.
To elaborate a little bit more: the first generation of LVADs were had large mechanical pumps and were huge -- they could only be implanted in people with a large chest cavity, excluding a large number of patients (especially women) from eligibility for their device.
Current popular models are continuous flow rotors that are much smaller (enabling their use in almost anyone) and are non-pulsatile.
However, there's been a big push to move towards pulsatile devices. This is mostly driven by mechanobiolgy studies that show that there is a difference in the cellular programs of cells that are exposed to a continuous shear force versus a pulsatile shear force. Accordingly, to more closely replicate the natural physiology of the heart, there has been a big push towards using pulsatile devices.
There is a difference between pulse and heartbeat, the pulse is from the veins and you can feel it even with an LVAD.
The audible heartbeat is from the heart sliding in the pericardium sac when it beats, many people lose the audible heartbeat after having heart surgery when the pericardium sac has to be cut or removed completely e.g. if someone is having a bypass surgery.
Yeah! Maybe the OP has the heart sounds confused with a pericardial friction rub, which can happen in pathological states and is due to the heart sliding against the pericardium.
I'm not being snarky. I saw several patients with LVADs on my cardiology rotation in medical school. As far as I know they are the only patients exempt from CPR if they have a cardiac arrest, although device failure should be the only reason for this.
There are two types of LVAD's- continuos flow and pulsed. LVAD's "piggyback" onto the existing heart and provide additional force to the left ventricle (which pumps blood to the body). The biggest issue with LVAD's is immune rejection and plaque buildup. As the body responds to a foreign object it will frequently form plaques on the LVAD's internal valves. It's very challenging to determine if this plaque buildup is occurring without literally opening up the patient's chest via surgery. If the plaque breaks loose, they frequently cause stroke or pulmonary embolisms.
I knew about the continuous flow, but hadn't considered that you wouldn't hear your own pulse as a result. My father in law has an LVAD, which has given him back a lot of freedom following a severe heart infection early last year which damaged his natural heart badly. He's now on the transplant list, so I'll point it out to him as a "hey, this could be weird" thing.
Do they mean that blood pressure is stable too, since you presumably wouldn't have a diastolic reading - no pressure reduction between beats, since there are no beats?
The diastolic reading isn't about pressure reduction in-between heartbeats but about the pressure created by the vascular walls.
When you usually measure blood pressure you increase the pressure to a value that's likely above the systolic value of the patient (say 180). Then you gradually release pressure. Once you hear a heartbeat that's the systolic value. Once you stop hearing the heartbeat that's the diastolic value, which is the vascular walls resisting the heartbeat
In this particular case instead of the usual heartbeat you'd likely hear something more like a constant flow but you'd still have systolic and diastolic values.
With a blood pressure cuff, what you are doing is collapsing the arterial wall with outside pressure. You increase the pressure above systolic blood pressure and then gradually reduce it until you hear a sound. This sound isn't the heartbeat, but is instead the result of turbulent flow in the blood vessel. While you are between systolic and diastolic pressure, only spurts of blood can flow through the vessel creating noise. Eventually, you reduce the pressure enough and blood even during diastole (which is lower pressure) can expand the walls of the artery against the blood pressure cuff.
So, in both cases what you are hearing is due to blood pushing open the vascular walls.
Not an expert, but from reading what an LVAD is and reading the article, these are two very different things. He had a full heart replacement device strapped to his back. As in, the blood ran out one tube, into the pack, then back into his body. An LVAD is an internal pump for the left side of the heart and you just provide it power externally. Not to discount your girlfriends experience at all, but that seem quite different.
EDIT:
Actually, watching a video, it looks like the tubes are for air maybe? Weird device in any case.
That's amazing. It's both awe-inspiring and unnervingly depressing to be reminded that we are ultimately just biological machines.
Reminds me of that procedure where a surgeon can freeze you, drain your blood, take out all your organs and then put them back in, stitch you up, pump blood back in and then warm you up and awaken you. It was like unplugging your PC, taking it apart and then putting it together and turning it back on.
Click-baiting titles on sites these days are probably driving people to the comments section first rather than RTFA. Crowd-sourcing and displaying in-place article titles on sites would make for a great browser extension. Might be as bad for site owners' short-term business goals as ad-blockers are.
Artificial heart designers may thus consider doing something to simulate the noise and vibration of a heart beat, to prevent any awkwardness after the transplant.
I registered as a donor in the UK. I received a leaflet saying that I should discuss this with my relatives because apparently those people have the power to kill the person needing my organs [1]. Fuck that.
Fun fact: The book Infinite Jest includes a character who keeps their artificial heart in their handbag. In one scene, the handbag is snatched by a passing thief which leads to the character shouting "She stole my heart, stop her!". As expected, this is tragically misconstrued by passersby who believe that the woman was in the middle of a sad yet not unexpected lovers quarrel, whereas in actual fact her heart had been stolen. Tragicomedy in the same scene.
Separate thought, if you were to replace your lungs with a machine that oxygenated your blood, could you calmly sit without breathing? Is the anxiety/impulse to breathe do to a lack of oxygen?
This oxygenator[1] along with a load of other kit and gas supplies replaces your lung function during a heart bypass. It swaps O2 and CO2. But it only works for hours before clots start to become a problem. The fibres in the oxygenator are coated with heparin to delay the complications.
Yes, you could sit without breathing. They do this in surgery all the time (heart/lung machine).
I suspect they want to minimize the blood's contact with anything because blood likes to clot, so doing it longterm without blood thinners might not work so well.
That's what is so amazing about this device: All other devices before it threw off so many clots they killed the patient rapidly.
In particular, in an environment that has insufficient oxygen in the air but that doesn't have carbon dioxide, you don't feel a desperate need to breathe; you just pass out and die.
This can and does kill people, in a variety of low oxygen situations. E.g. labs with liquid nitrogen freezers are mostly now fitted with O2 alarms to warn occupants about a dangerous and undetectable low O2 situation. Since you're still able to expel CO2, you literally won't feel anything wrong until you just collapse and quietly asphyxiate. Movies get this wrong all the time, and it bugs the heck out of my biotech friends with safety training with aforementioned labs.
Your body will prompt you to breath when either CO2 levels are too high or O2 levels are too low. In your example the subject is still breathing even if he isn't getting O2.
One problem ER docs see periodically is the CO2 "sensor" can become broken in patients with chronically high blood CO2 levels, i.e. people with certain types of COPD. They only breath when their blood O2 levels are low, and if you give them oxygen they just stop breathing.
Hence the recommended method of life exit for people with terminal illness is to use a hood connected to Helium. Of course you need some "assistants" to remove the evidence since most places assisted suicide is illegal.
Excuse the morbidity, but if this type of asphyxiation is essentially pain and stress free, would it not be a humane method for euthanasia or even for capital punishment?
Also search for “exit bag”. You’ll find instructional images, as well as an instructional video made for the sick and elderly, about using this technique to commit suicide.
I guess one thing to look out for is the smell of rotten eggs in a server room. From what i understand that is a sign that the UPS batteries are venting hydrogen sulfide.
That or sulfur dioxide, yeah. I've smelled the latter in an office that doubled as a data center, when one of the UPSs' charge regulation circuit went wonky and overdrove its batteries.
That's probably not a major asphyxiation risk unless you're trapped in a room with it, though, because, unlike inert gases like helium or nitrogen, sulfur compounds are irritating as hell - a UPS boiling its batteries will send you fleeing for the nearest source of fresh air, with eyes and nose streaming, before it'll suffocate you.
CO2 buildup is what drives the panicked "I can't breathe" response. If there's no CO2 buildup and no oxygen, it's a rapid and apparently peaceful lights out.
How many organs can you do this for? Heart, lungs, kidneys at least.
'Brain-in-a-jar' seems like the most achievable form of immortality at the moment.
Our bodies are more complex than we can design for yet. Most organ replicating machines will start to fail after a couple of hours due to complications like clots. The heart is probably the simplest due to it's very simple function. We also have kidneys mostly working. But everything else is still problematic.
It starts with the Jarvik-7 artifical heart from the 1980s (first seen as a success, then as a failure) and then moves on to today's temporary and permanent artifical hearts.
Really interesting documentary. Thanks for posting this.
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Some highlights:
- these new SynCardia artificial hearts are basically the same as old Jarvik-7 hearts (part that goes inside patient's chest), save for different sizes available today
- just the external part is now more modern (thanks to advances in power sources they can be now portable)
- big problem with Jarvik-7 at those earlier times were infections and blood clotting (leading to strokes), but doctors today know better how to manage this (as far as I understood, this is not due to better mechanical design of the heart but due to better medication / monitoring / protocols compared to ~30 years ago)
- these new SynCardia hearts were used for already ~1,600 patients (as "bridge" while waiting for heart transplant)
- FDA approved trial for use of these artificial hearts as permanent solution (no heart transplant needed), the first patient already got implanted this heart for permanent use
I would guess so because beta-blockers are also prescribed for anxiety as well as various heart conditions, and breaking the feedback loop is the intended effect. I'd imagine therefore that you'd be a bit less anxious as a result.
Carmat have a competing device that's been implanted in 5 patients so far. It is much more technically advanced, with Alan Carpentier designing, I think, to prevent blood clots. However, it's. A pump based device Nd the jury is still out on how long pump based devices can last. They expect the xarmat heart to last 5 years.
Carmat gets a lot of bad press when each patient with their pump dies, even though the press does not realise patients would be long dead without them.
I don't know if the press are that important tbh. They have now progressed to clinical trials. If they are successful they will make and sell millions of them. 23andme showed that press isn't that important in medicine - pleasing the FDA is the name of the game.
Love seeing these stories about the will to live and fighting through hardship and making the most of every opportunity. These sorts of folks - who just want to be normal - really strike a chord with me. Fascinating specific instance and type of treatment.
I wonder if it is just better to have the artificial heart for the rest of your life? With all the complications with having a heart transplant, it seems like it could be equally dangerous.
Note, I'm a lay person, and have no clue. Just pondering.
Its good to hear people are working on things like these, artificial hearts prolonging life. Gives some perspective and your own problems pale in comparison.
This is not new or particularly interesting. Dick Cheney had one of these for a long time. I knew someone who had one too. I'm not sure why this is being written about as if it's new.
I had a girlfriend with a similar device attached to her (an LVAD). At first it was a little unnerving seeing her unplug the batteries that were keeping her alive and charge them every night. It quickly became normal for me. Life with it seemed relatively normal except she had to have a purse with her at all times (it carried the batteries).
The interesting part was when she received a transplant and went cordless. After being attached to it for two years and not having a heartbeat the sound of her heat beating kept her up at night for a couple of weeks. I hadn't even considered the beating of a heart to be relevant to our daily lives until she had mentioned it once she heard hers beating again (an LVAD is just a constant velocity pump. The blood is always flowing).
Not sure how much it really adds to the conversation other than an interesting anecdote.