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Living Without a Pulse

SteamyMobile writes "Can you live without a pulse? Yes, now you can. The reason why we have a pulse is because it's hard for evolution to result in turbines or continuously spinning things. The next generation of artificial hearts may have no pulse. They also have no bearings, so they should last much longer than previous attempts. In fact, engineers don't give a predicted lifespan on these models. How would your life be different without a pulse?"

66 of 759 comments (clear)

  1. Hmm by grub · · Score: 5, Funny


    How would your life be different without a pulse?

    I would have had much more in common with my ex-wife.

    --
    Trolling is a art,
  2. He's Dead, Jim. by mfh · · Score: 5, Funny

    FTA: "The pump also has a curious side effect: people implanted with the device have no pulse."

    They had better put an obvious port on it so paramedics know it's there before sending voltage through.

    I can see the first really drunk guy with one of these taking a nap on the beach:

    "ZZzzzzzzZZZZzzzzzZZ"

    "Sir!"

    "Oh my GOD! He's Dead, Jim!!!"

    "He's got no pulse! Call an ambulance!"

    (ambulance arrives, 10min later)

    "This man has no pulse! I've been giving him CPR since I called you guys and I can't get a signal!"

    "CLEAR!!!!!!!!!!!" "ZZZZAPP!!!!" /dies

    --
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    1. Re:He's Dead, Jim. by akiaki007 · · Score: 5, Informative
      (ambulance arrives, 10min later)

      "This man has no pulse! I've been giving him CPR since I called you guys and I can't get a signal!"

      While ths scenario is pretty funny...most CPR certified professionals check for breathing, not a pulse. And if they didn't, then they shouldn't be certified. Yes, they also check for a pulse, but not before they check for breathing. Depending on the body fat on a person, the pulse isn't always easily detected.
      --
      "Time is long and life is short, so begin to live while you still can." -EV
    2. Re:He's Dead, Jim. by sql*kitten · · Score: 4, Informative

      most CPR certified professionals check for breathing, not a pulse.

      Yup, ABC, Airway, Breathing, Circulation. One of the fist things they teach in First Aid class. You can have a hearbeat while not breathing, but you can't breathe without a heartbeat.

    3. Re:He's Dead, Jim. by tomknight · · Score: 3, Funny
      Have yourself tatooed.

      Reminds me of an article I read about an old lady who doesn't want to be revived if her heart stop (she seems to think that that's probabaly a good time to call it quits). The problem is no-one's going to check your wallet for a consent card for CPR, so she's had her chest tatooed with a warning saying something like "Get thos f*cking this away from my f*cking chest. If you revive me I'll sue your arse off!". No, what wasn't quite it.... but I wonder if she could sue someone for saving her life in that way (against her wishes? Would she be able to get some sort of support for the next time she falls ill and has to pay a shite load of dosh for pain releif (or whatever)?

      Tom.

      --
      Oh arse
    4. Re:He's Dead, Jim. by SEWilco · · Score: 3
      "CLEAR!!!!!!!!!!!" "ZZZZAPP!!!!" /dies

      Why would he die?
      Running electricity through where his heart used to be would not affect the insulated pump.

      However, there should be a label: "Normal blood pressure 90 psi. Check oil every two years. Turn off this switch before autopsy or burial. Press red button before vigorous exercise."

    5. Re:He's Dead, Jim. by The+Tyro · · Score: 3, Informative

      They expand on the acronym in a couple of scenarios.

      ATLS (Advanced Trauma Life Support, a program by the American College of Surgeons) expands that to ABCDE: Airway, Breathing, Circulation, Deficits in neurologic function, and Exposure (remove/cut off all clothing... easier to find injuries and wounds that way).

      Also, the "C" in the old "ABC" acronym is also supposed to stand for Cerebral protection in addition to circulation. I've also heard CPR termed "cerebral pulmonary resuscitation." That's probably a fair substitution, since your main goal in CPR is to protect the brain by creating a low-flow rather than a zero-flow state (contrary to what some folks think, CPR doesn't restart the heart from a V-fib/V-tach arrest... generally only electricity can do that).

      Once your brain's dead, you're dead... even if your heart, lungs, kidneys, etc are all working normally. Those folks become organ donors, or should...

      Let me put in a plug here... PLEASE CONSIDER DONATING YOUR ORGANS. Please... talk to your family about it, get it on your driver's license or living will. Lots of people need organs, and if you don't need yours anymore (and you have no deep religious/philosophical objection), why not donate them? Just a thought...

      --
      Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
    6. Re:He's Dead, Jim. by strike2867 · · Score: 3, Funny

      Actually I think it would go like this:

      "ZZzzzzzzZZZZzzzzzZZ"

      "Sir!"

      Checks pulse "He has no pulse, start CPR."

      "Get the hell off me."

      "AAAAAAAA".

      --

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    7. Re:He's Dead, Jim. by ReTay · · Score: 4, Interesting

      "The problem is no-one's going to check your wallet for a consent card for CPR, so she's had her chest tatooed with a warning saying something like "Get thos f*cking this away from my f*cking chest. If you revive me I'll sue your arse off!". "

      Kind of remindes me of my EMT instructor, She has three tattoos
      There is an "X" two fingers above her zyphoid process (where you put your hand for chest compressions)
      and underneath is says push here.
      She has the outline of two fingers on her right wrist.
      And a circle around her vein in her arm.

      Lets just say that if she didn't train them she doesn't trust them.
      Then again she is of the opinion that no matter how far along a woman is in labor when you pick them up in an ambulance if the baby is not born in a hospital your driver is to slow.

  3. What will Nurses do... by JagRoth · · Score: 3, Funny

    ... at the Doctors office without being able to take our pulse while they stall until there is a doctor available to see us?

    1. Re:What will Nurses do... by Bob+McCown · · Score: 5, Funny

      I guess they'll just put a timing light on my, er, finger, and check my RPM.

  4. Nature's solution is best in at least a few ways. by etymxris · · Score: 5, Interesting
    ...the VentrAssist is less likely to damage red blood cells because it moves the blood more slowly with a bigger impeller.
    That's why you haven't seen more propellor based solutions--they tend to chop up the cells. Propellors work great on something you don't mind mincing up, such as air for planes, water for boats, and ice for that delicious smoothie. But I'd be hesitant to send my red blood cells through a propellor. I know they're talking about impellers and not propellors, but I see little difference in damage capacity.
  5. variable speed by tverbeek · · Score: 5, Insightful
    How would your life be different without a pulse?

    I wouldn't be able to tell how hard I'm exercising. Which brings up the point that these turbines are going to have to be variable speed if they're going to accommodate humans' varying oxygen needs.

    --
    http://alternatives.rzero.com/
    1. Re:variable speed by Tassach · · Score: 3, Insightful

      Turbines are generally happiest when running at a constant speed. However, it's not necessary to vary the turbine's speed to duplicate the heart's action -- what you really need to vary is the net flow rate. A variable net flow rate can be achieved even with a constant-speed turbine with some valves and clever plumbing.

      --
      Why is it that the proponents of "one nation under God" are so eager to get rid of "liberty and justice for all"?
    2. Re:variable speed by SargonZ · · Score: 5, Informative

      Actually, current pacemakers can only be set to one speed, so people who have these devices already have the limitation of non-variable heartrate. While this is a setback for the pacemaker-using crowd, almost all agree that having a non-variable heart rate is better than having no heart rate at all.

    3. Re:variable speed by Kupek · · Score: 4, Funny

      I can generally tell how hard I'm exercising by how much it hurts.

    4. Re:variable speed by Rogue974 · · Score: 3, Interesting

      This is something I know about, I am an engineer and work with centrifugal pumps (engineering classification of these impeller/turbine pumps. You can make them variable speed and use the speed of the impeller to control the flow of the medium being pumped. There are many advantages to this, but it is not the common flow control scheme. Most of the time, the speed of the impeller is held constant and a control valve on the discharge side of the pump is opened and closed. As the discharge vale is open, flow goes up, as the valve is closed, the flow goes down. I woudl venture to guess, that the muscles that apply pressure to arteries to direct the blood flow (an everyday normal activity in all human beigns) acts as the flow control and the pump just sits at normal speed. If you have a variable speed pump, they would have to tap into the nervous system to determine the blood needs of various organs/tissues and use that as speed control, not going to happen, or give you a rheostat on your side that you coudl turn up and down the spped of the impeller based on what you were doing (sarcasm). Summary, constant speed centrifigal pump with the flow control being down by the discharge valve (this case muscles on the arteries that are already there) and the pump impeller speed never changes.

    5. Re:variable speed by CharlieG · · Score: 3, Informative

      What? Almost all current generation pacemakers are rate responsive - they have a minimum rate, max rate, and rate curves, and they use various sensors (usually activity (movement) from what I understand, but also breathing rate) to change from one setpoint to another.

      I've been with my Dad when they check the programming of the resting and exercise rates on his pacemaker, and set them, and the transition point - It's all done with an inductive coil that is places over the main module of the pacemaker - they can even check the settings by phone

      --
      -- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
  6. If I had no pulse... by garcia · · Score: 3, Interesting

    I wouldn't have to take the two different high-blood pressure meds that I do now. That would save me about $35/month and the random side effects that go with taking these medicines (shortness of breath when exercising, dizziness when getting up to fast, etc).

  7. Pulse by kc0re · · Score: 5, Interesting

    I heard that people without pulse get a sense of disorientation and un-equilibrium. Especially those with screw drive hearts. Since the body has operated on a pulse for so many years, I have talked to people that have these screw drive heart devices, and they initially they couldn't even sleep at night because they didn't have the pulse in their ear.

  8. cosmetic surgery? by mblase · · Score: 5, Funny

    I wonder how many goth vampire wannabes will elect to have these implanted, just to improve their authenticity?

  9. Problems by BWJones · · Score: 4, Interesting

    There are certain advantages to having a "pulse". Examples are: The alternating low and high pressures may allow the bodies baroreceptors to better control blood pressure and there are other important feedback mechanisms associated with having alternating high and low pressures in response to the heart contracting. I would worry that some of the new pumps could undermine those mechanisms.....

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    1. Re:Problems by BWJones · · Score: 5, Interesting

      Perhaps I should have clarified some of this for the non-biologists here. Baroreceptors are receptors found in the aortic arch and internal carotid arteries that are sensitive not only to overall pressure in the cardiovascular system, but also to rates of pressure changes which are critically important in cases where you suddenly undergo rapid loss of blood pressure. (like when you are bleeding......alot). In cases like these, your body starts a series of physiologic changes to keep you alive and interfering with those sorts of things were what I was referring to.

      These issues may also be important for maintaining cardiovascular fitness as well as recovering from myocardial infarcts, and because the alternating pulse pressure is eliminated in turbine models, I would worry about possible losses of negative feedback which might result in runaway blood pressure which could lead to hemorrhagic strokes, kidney damage and other such unpleasantries.

      Oh, and since the Slashdot crowd appears to be preoccupied with sex, there is some evidence that penile erections are dependant upon alternating pressures to, ahem.....get the job done.

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    2. Re:Problems by endx7 · · Score: 5, Insightful

      The again, not having a working heart at all would probably undermine those mechanisms as well...

  10. still a pulse by uid0mako · · Score: 3, Informative

    from the article:
    "LVADs are not designed to replace the heart but are implanted alongside it under the rib cage."

    Therefore your heart is still there beating. This is just a supplement to it.

  11. Internal Metronome by the+darn · · Score: 3, Funny

    Then I'd not only lack rhythm, I'd have no beat, either!
    Semi-seriously, though, would this eliminate the possibility of things, uh, throbbing?

    --
    Ceci n'est pas un post.
  12. 'Detecting a pulse' for those who don't have one by EnglishTim · · Score: 5, Interesting

    A few months back I did a first-aid course at work. One of the interesting things I found out was the technique they use for checking to see if someone's heart is beating:

    Basically, you pinch their earlobe. This forces the blood out of the lobe, and then you let go. If colour returns to the lobe, then the heart is beating and blood has been pumped back in. If it does not then blood is no longer moving around the body.

    This technique would probably also work for those with no pulse.

  13. Whatever You Do...Don't. Fall. Asleep. by GoatChunks · · Score: 3, Funny

    With no pulse, I'd be afraid to take a nap in the park. "God damn it! I'm in the morgue again!"

    What would be worse though...I imagine most of the people getting these will be rather up in years. And, as old people and dads do, they will inevitably fall asleep in front of the TV.

    The first 6 or 7 times they do this, their family will think they're dead and will start going through his pockets. But then it becomes a "boy who cried wolf" scenario, and they think he's just sleeping when he's actually dead. Next thing you know, ol' grandpa has funked up the Lazy Boy, and they have to take him out in a bucket.

  14. predicted lifespan by sacrilicious · · Score: 5, Funny
    They also have no bearings, so they should last much longer than previous attempts. In fact, engineers don't give a predicted lifespan on these models.

    Marketer: So what's the predicted lifespan for these models?
    Engineer: We're, uh, not giving one.
    Marketer: Because it's so long?
    Engineer: I'm sorry, I didn't catch that. And now I have to go. (leaves)
    Marketer: (calling after him) I'll hold you to that!
    --
    - First they ignore you, then they laugh at you, then ???, then profit.
  15. Re:Hmm (ex wife, but seriously...) by kiatoa · · Score: 5, Insightful

    I'm sure someone will be adding their favorite politician to this thread but seriously - I'd put money that there will be some consequences to not having a pulse. Valves will not get the exercise they need or something. N million years of evolution (or 7 days of design if that is what you buy into) means that there are probably lots of subtle interdepenancies of a pulsating blood supply. Of course some of the consequences might well be good...

    --
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  16. How would the body react? by akiaki007 · · Score: 3, Insightful

    Considering our veins are outfitted with nice valves that prevent the backflow of blood in between pumps of the heart, what would happen to them when they are no longer needed? One would think that they just wouldn't close, which I suppose is fine, but it just seems that they might create an unwanted side-effect.

    Also, it is possible that our organs aren't capabale of handling blood in a constant stream and they need those precious milliseconds of rest in between beats.

    Perhaps I should've stayed in medicine and then I'd know these answers, but since I didn't, anyone know or have a better theoretical idea?

    --
    "Time is long and life is short, so begin to live while you still can." -EV
  17. Time to lower /. dating standards by Mr.+Neutron · · Score: 5, Funny

    "Must have a pulse" is no longer a requirement. :-)

    --
    dinner: it's what's for beer
  18. Re:What? No MD's here? by stephenbooth · · Score: 4, Funny

    The golf course hasn't put in WiFi yet.

    Stephen

    --
    "Don't write down to your readers, the only people less intelligent than you can't read" - Sign on Newspaper Office Wall
  19. Re:'Detecting a pulse' for those who don't have on by imag0 · · Score: 5, Funny

    Well, that and the guy you just checked screaming "OW! You just pinched me fucking ear!" will probably help as well.

  20. Had it in the lab, years ago... by gillbates · · Score: 3, Insightful

    When I took my freshmen chemistry courses in college, we had electronic stirs - you'd drop this plastic coated magnetic "plug" in a beaker, and then set the beaker on the machine. An alternating magnetic field would cause the plug to spin, stirring the fluid.

    And now, 15 years later, someone finally figured out that you could apply the same principle to moving blood. Amazing.

    I've always wondered why people bleed to death on the operating room table from trauma. When I worked as a mechanic, I had a supply of various diameter tubings readily available so I could plug a vacuum leak when diagnosing a carburetor malfunction. I've never understood why surgeons can't do the same with blood vessels - the patient is bleeding from a major artery, and it never occurs to them that the could slice the artery in half and connect the ends with surgical tubing?

    I had always thought that there must be some really scientific reason for this, but now it occurs to me that it might just be ignorance. It took medical science 15 years to figure out that a lab stir would work better than bearings? I knew that as a freshmen! Ask the hubble designers - it uses frictionless magnetic bearings - maybe they could have clued someone in?

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  21. Re:Hmm (ex wife, but seriously...) by EpsCylonB · · Score: 3, Interesting

    I had a very similar reaction, IANAHS (I am not a Heart Surgeon) but in the article it says...

    it only has one moving part, a spinning impeller that drives a continuous stream of blood.

    Surely the human body is not designed for a continuous stream of blood ?.

    Saying that I am sure that this has all been researched thorougly to get to this stage and my limited medical knowledge probably isn't very useful.

  22. But seriously... by The+Tyro · · Score: 3, Informative

    the procedure is actually to assess them first... something along the line of shaking them and asking "Annie! Annie! Are you OK?"

    If they answer "yes," you're done.

    I realize you were only joking, but the entire clinical picture needs to be taken into account.

    My favorite EMS call is the patient with a minor head injury who is rushed in with a "blown pupil." When you go see the patient, they're awake and alert, not vomiting, not somnolent, etc. It's usually someone who's new, and doesn't understand the pathophysiology behind Uncal Herniation and 3rd nerve compression.

    Back to the topic at hand... I wonder if the lack (or blunting) of the systolic peak and diastolic trough in the blood pressure would lead to any physiologic problems? According to the article, the device is actually a Left Ventricular Assist Device (the ole' intra-aortic balloon pump is the classic example of such a device). It steals blood from the left ventricle and steadily pumps it into the aorta... but I wonder if it has any effect on the coronary arteries?

    The coronary arteries mainly fill during diastole, when the aortic valve closes and blood floods the coronary sinuses on the aortic side of said valve... since this device essentially "steals" blood from the left ventricle and injects it somewhere downstream, I wonder if the coronaries get the same filling? (I suppose it's a question of where you place the downstream catheter.) It might not make a difference if you have clean coronaries, but if you've got a Left-main stenosis, it could be bad to drop that filling pressure...

    In a perfect hydraulic system, it wouldn't matter, since pressure injected in one location would increase pressure in all locations... but arteries have compliance, and they can flex.

    Interesting device... it'd be nice to know some more details.

    --
    Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
  23. Red October of the Heart by Venner · · Score: 3, Interesting
    Rock on caterpillar drive, I say. I'm thinking Hunt for Red October here.

    Lol. As a former nuclear/plasma physics graduate student, it makes me laugh even more. Do you know how that caterpiller drive actually works? The field of study is called magnetohydrodynamics and is one of the most @*#%$!* involved things I've studied...

    Basically, you have an electric field of some sort or readily available ions (think, salts in the ocean water), apply some strong magnetic fields of differing strength, and cause a forceful ion drift in the direction perpendicular. I just call it Evil Fluid Dynamics With 50 Other Variables.

    As an aside, since there are relatively fewer dissolved salts, the Red October's caterpiller drive wouldn't work in fresh water. Neat eh? Not that there are terribly many huge bodies of fresh water where you'd worry about silent submaries. :-)

    At any rate, there are dissolved salts in blood, aren't there? So you could theoretically do this for a heart pump. But who knows what the heck it'd do to the patient and I'm guessing you'd need a whole lot of auxiliary equipment.
    --
    A preposition is a terrible thing to end a sentence with.
  24. Re:Nature's solution is best in at least a few way by sql*kitten · · Score: 4, Interesting

    I'm wondering about the little one-way valves throughout the body which aid the pulse. Does such a system damage or suffocate those valves?

    Also, the heart isn't the only pump in the body - the muscles in your legs help return blood to the heart when you run. That why if you run then stop abruptly you feel faint, because suddenly the load on your heart has suddenly increased and it needs to ramp up to pump blood all the way up to your head at a usable pressure (which is one reason you should warm down properly after exercising). How would the impeller interact with "pulses" from the legs?

  25. This would have really messed up Star Trek by ellem · · Score: 4, Funny

    He's Dead Jim. No wait wait he's alive.

    --
    This .sig is fake but accurate.
  26. Re:Hmm (ex wife, but seriously...) by D3 · · Score: 4, Interesting

    Actually, I read a Reader's Digest article about a similar pump a couple years ago. Some young girl in England had a viral heart infection and would have required a transplant. Instead, they stopped her heartbeat and implanted a constant pump like this. The doctors were all concerned about the effects of not having a pulse, not having 2 bounces for blood pressure measurements.

    She lived quite well with the device and the stopping of her heart actually let the heart muscle repair itself. It turned out that resting the muscle was very good for it. She was eventually taken off the device and her heart restarted.

    So no, there are not the adverse effects doctors had theorized about.

    --
    Do really dense people warp space more than others?
  27. mdiarmspafpothama by TamMan2000 · · Score: 4, Insightful
    I had a very similar reaction, IANAHS (I am not a Heart Surgeon) but in the article it says...

    it only has one moving part, a spinning impeller that drives a continuous stream of blood.

    Surely the human body is not designed for a continuous stream of blood ?.

    Saying that I am sure that this has all been researched thorougly to get to this stage and my limited medical knowledge probably isn't very useful.


    mdiarmspafpothama (My dad is a retired medical school professor and former president of the heart association midwest affiliate) and he agrees with you.

    I told him about a woman in england that had an earlier version of one of these for several days while waiting for a real (human) heart (this was a few years ago). His imediate reaction was that pulsitile flow probably slows the build up of plaques in the arteries, and that people without a pulse would, IHNSHO (in his not so humble opinion), be more likely to experience blockages.

    Of coarse that was just his gut reaction and he has not researched the topic...
    --
    "I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
    1. Re:mdiarmspafpothama by GPSguy · · Score: 5, Interesting

      Well, having actually spent some time doing partial and total artificial heart research, including about 6 years with the earlier LVAD (pulsatile) technology, I'm of two minds about this.

      1. I don't believe we'll see increased atherosclerotic plaque deposition due to non-pulsatile flow. I'm currently subscribing to the theory that plaque is related in chronic bacterial infection of the vascular intima.
      2. There was some evidence, but poorly followud up in the past, that renal function was on the short list of critical elements requiring pulsatile flow. One reason for inadequate continuing studies was that the problems with on-pump anticoagulation, infection and anesthesia tended to introduce enough variables to make isolation of the pulse issue too obscure.
      3. There have been a number of reports in the past, some as long as 15 years ago, of surgeons using the Biomedicus BioPump, a similar design, for extracorporeal bridging support to transplantation, or similar to the anecdote below, to place the heart at rest to allow its recovery. I'm aware of many cases (I participated in at least 10) of multiple-day attempts, and at least 2 or 3 trials of several weeks. Realize that the patients were already moribund, so supporting them in bridging, awaiting a suitable donor, was their last and sole chance for survival. And, no, most of them didn't survive to transplant.

      I'm intrigued. I'm out of the business now, but I'm convinced that we're overdue for some real breakthrough to make implantable artificial devices for continuous perfusion a viable alternative to transplantation with the limited pool of donors.

      --
      Never ascribe to malice that which can adequately be explained by tenure.
    2. Re:mdiarmspafpothama by Baseclass · · Score: 5, Funny
      mdiarmspafpothama (My dad is a retired medical school professor and former president of the heart association midwest affiliate)

      You don't have to spell it out, we're all familiar with that acronym.

      --
      ^^vv<><>BA
    3. Re:mdiarmspafpothama by Loco3KGT · · Score: 3, Funny

      mdiarmspafpothama (My dad is a retired medical school professor and former president of the heart association midwest affiliate)

      You don't have to spell it out, we're all familiar with that acronym.

      Well now I feel like an idiot for going "em-dia-rmspaf-pothama... what the hell is that?" *click shortcut to open dictionary.com in new tab*

      --
      Blessed be he who reads this post, Cursed be he who tells my boss.
    4. Re:mdiarmspafpothama by DavidTC · · Score: 3, Interesting
      Pacemakers are just replaced, completely. As the battery lasts about ten years, and advances in technology happen during that time, it would be rather stupid to just replace the battery, especially considering you have to cut people open regardless. Plus, the ability to open a pacemaker would be another point for fluids in the body to sneak into the pacemaker.

      The wires running to the heart, called 'pacer leads', are not replaced, though, so it's just a simple matter of slicing open the skin and hooking up a new pacemaker to the lead. (Usually they have two leads, so they can pick which ever one seems better, and have a backup if one breaks.)

      Now, what would be vaguely useful would be a way to recharge them from outside, by induction, or, hell, body motion. They can be programmed from the outside, but not charged, which I think is stupid.

      Of course, pacemakers use a lot less power than artifical hearts. Pacemakers just give the heart a very tiny shock to get it to automatically work, because the heart's natural pacemaker has been screwed up somehow. A lot of times they only have to do it every few seconds or so. Artifical hearts have to move a hell of a lot of blood continually around the body, whereas you could probably operate a pacemaker from a watch battery for quite some time.

      I have some old pacemakers laying around (They give you the old one when you get a new one. Weird, eh?) and I've been tempted to take then apart to see how much is the battery. I suspect 90% of them.

      --
      If corporations are people, aren't stockholders guilty of slavery?
  28. so what you're saying by BitterAndDrunk · · Score: 4, Funny
    "Depending on the body fat on a person, the pulse isn't always easily detected."

    So basically most Americans effectively have no pulse already? I swear, we're always ahead of the curve.

    --
    You better watch out, there may be dogs about . . .
  29. BP and pulse are issues by coyote_oww · · Score: 4, Insightful
    A lot of hospitals use automated blood pressure and pulse equipment to keep tabs on patients. Currently, this equipment can sound an alarm to attract the attention of a nurse if BP or pulse gets out of whack.

    So... it appears we'll have to come up with a new way to measure blood pressure, particularly. Presumably, the best way to do this is to fit the turbine with inlet and discharge pressure sensors, and a flow meter. Step 2 is to establish some sort of numbers for what is "normal" for turbine heart patients.

    This ups the ante for health care professionals by a bit. Not only do you need to know normal ranges, consequences, and treatments for standard BP and pulse ranges, you would need to be familiar with turbine pressure and flow ranges as well.

  30. Re:Hmm (ex wife, but seriously...) by Anonymous Coward · · Score: 5, Informative

    Only arteries have a pulse. The blood flow is as follows: heart -> arteries -> capillaries -> veins -> heart. By the time the blood gets thru the capillaries to the veins the blood pressure is vastly reduced and the pulsatile flow generated by the heart is not felt in the veins. Hence veins do not have a pulse. The valves in the veins have nothing to do with the pulsatile flow of the heart and hence a constant flow heart will not affect the functioning of the veins in any way. Venous problems like varicose veins, cirrose like vena portalis deformities are not related to how the heart pumps.

  31. Re:Hmm (ex wife, but seriously...) by GPSguy · · Score: 5, Interesting

    When you place the heart at rest, you remove the load it sees, and use an artificial pump to do the work.

    You don't stop the heart. Even today, with cardioplegic solutions significantly advanced, supplemented with NAD-compounds and amino acids, stopping the heart bears the significant risk that you can't get it restarted again.

    Cardioplegia for cardiac surgery involves infusing a potassium-rich solution into the coronary arteries, which stops the heart in diastole. Further, the solution is cold, and the heart is bathed in an iced saline slush to cool it further and diminish its metabolic requirements. At this point, the heart is *NOT* getting a blood rich perfusion (barring the use of blood-based cadioplegia, which I'm still not sure is as good an idea as some others think) medium.

    If you were to start reperfusing the arrested heart with blood, with a normal electrolyte composition, the extra potassium would be washed out, the heart would rewarm, and if it has sufficient energy stores, and a sufficiently normal physiology, it would begin to contract again.

    So: To put the heart at rest, you unload it, keep the blood chemistry as normal as possible, maintain good nutrition status (parenteral alementation), and see if the heart muscle recovers.

    --
    Never ascribe to malice that which can adequately be explained by tenure.
  32. Re:Hmm (ex wife, but seriously...) by baxissimo · · Score: 5, Funny

    > (IMAD) I am a doctor.

    Good thing your patients' lives don't depend on your ability to create acronyms. ;-)

  33. Whole Heart Version? by Xesdeeni · · Score: 4, Insightful

    I saw this technology in a documentary on PBS at least fifteen years ago, but it was for a full heart replacement. They were reviewing artificial heart research after the Jarvik-7 was implanted. The odd thing was that the show went into a bit of detail about a centrifugal pump and its power supply, but I haven't seen anything about it since then.

    Apparently a small nuclear pellet was used in the battery, which was in a lead-lined container about the size of half a D-size battery. The battery could be implanted completely, unlike the Jarvik, which requires a dangerous (susceptible to infection) tube running through the skin to a suitcase sized pneumatic pump. The issue they focused on was the danger of the radioactive pellet. Apparently concern had been raised about the possibility of an artificial heart recipient being in a plane crash. The fear was that the radioactive battery would leak. So they went to great pains to test it, including shooting it out of a gun, to show it was safe.

    IIRC, the concept of being without a pulse, and the need for more research about this, was mentioned almost as an afterthought. But I've wondered ever since then what happened to this type of artificial heart. A completely self-contained apparatus would seem to be a godsend. But I always assumed that lack of pulse was the gotcha.

    I even discovered that Marilyn Vos Savant, whose Q&A column appears each week in the national Parade insert to many Sunday newspapers. is married to Robert Jarvik, and consdered writing him in care of her about this device. But I never got a round tuit.

    Xesdeeni

  34. Does anything depend on a pulse? by Theovon · · Score: 4, Insightful

    Did you know that many clocks depend on your outlet current being exactly 60 (or 50) Hz? In the US, I believe federal regulations dictate that over some specified period of time, your wall outlet has to count to the right total number of oscillations. When load is high, causing the generators to spin slowly, the cycle count can get off by minutes, and the electric company has to make up for in off-peak periods by running the generators faster.

    In biological systems, we often see unusual dependencies. I think I read somewhere that certain birds can't swallow without gravity. And why not? It's there! Make use of it! That's the way evolution works. Nothing is more redundant than it needs to be (well, we can talk about transposons later). In humans, bone density is dependent on load, which is why our bones atrophe in weightlessness.

    So, given that we HAVE a pulse, I would be surprised if some part of your body didn't take advantage of it.

  35. Re:Hmm (ex wife, but seriously...) by lucifuge31337 · · Score: 4, Interesting

    While I mostly agree with you, I have one nit-pick/addition. As a former meat wagon operator (oh, sorry...I mean paramedic), checking for blood flow in extremities can be done by checking capillary refill as well.

    Huh? Yeah...push on your fingernail. The nailbed turns white. The time it takes to go back to pink/red is your capillary refill time. Should be 1-2 seconds max, or you've got problems....not necessarily low bp....dehydration and low o2 saturation will do it too.

    That being said, no pulse....how the hell do I get a BP? I'm guessing my pulseox won't work either. Do they have an LCD control panel mounted on their chest so I can check and adjust their BP with a little screwdriver? I can see this type of thing really compilcating/confusing emergency medicine.

    --
    Do not fold, spindle or mutilate.
  36. Living Without A Pulse by Doc+Miller · · Score: 5, Insightful

    I develped a pump for extracorporeal circulation of blood back in the mid 1970's and had to take a lot of these problems into account. My pump was pulsitile and had a very physiologic wave form including dichrotic notch. It also had 2 orders of magnitude less damage to red blood cells than the best pumps on the market at the time. (at least with the cow blood I experimented with) (Read on for an explanation of this) After spending a lot of money on patent lawyers, the device got shelved when I couldn't get a clear patent on it. I think people here on slashdot are missing the point of continuous (non-pulsitile) flow. The elasticity of the arteries especially the aorta actually adds to the pulsitile nature of blood flow. There is an artifact seen in blood pressure measurements called the dichrotic notch that is a direct result of this. If it is absent it is an indication that hardening of the arteries has taken place. The main purpose of circulation is to get blood to tissues and organs. Once there, it has to infiltrate the organs deeply in order to properly transfer oxygen and nutrients and carry away wastes. We were evolved with pulsitile flow and as a result the perfusion of organs and tissues is better with this type of fluid dynamic. That doesn't mean it won't work with constant flow, only that it won't be as efficient. It may take several years before these inefficencies result in some kind of problems. An increase in plaque deposition comes to mind because the tissues arent stretching and contracting. The other problem with turbines and impellers is the "waring blender effect" where the blood cells are "chopped up" by the spinning blades. This leads to hemolysis (release of hemoglobin into the blood form broken red blood cells) which puts a strain on the kidneys which aren't beilng perfused properly because of the non pulsitile flow, etc. etc. you get the picture. Anyway, it's interesting but not a permanent solution.

  37. Plausible explanation by Peter+Millerchip · · Score: 5, Interesting

    You said: Can anyone offer a plausible explanation for how any one of the pieces of a bacterial flagellum would offer that bacterium some sort of advantage?

    Why yes, I think we can!

    A nice quote from the conclusion: ...the very fact that a step-by-step Darwinian model can be constructed that is plausible and testable significantly weakens the suggestion that extraordinary explanations might be required.

    Nice try though...

  38. Re:lack of pulsatile flow and coronary vessles by henryhbk · · Score: 4, Interesting
    I am an internist, but we deal a lot with cardiac surgery patients.

    A major problem with continous flow would seem to be the diastolic part of the cardiac cycle (when the heart is refilling) is critical for back-flow from the body (arteries do not have valves) into the coronary artieres (the arteries that feed the heart). The aorta (main artery from the heart to the body) is elastic, so a large bolus (fluid surge) of blood is ejected into the aorta, stretching the aorta during systole (contraction of the heart). When the heart then relaxes (diastole) the stretched aorta recoils, and squeezes blood both forward and backwards. The heart has an output check valve at the aorta (aortic valve) which prevents it from completely flowing back; however a small takeoff (the sinus of valsalva) allows the blood to surge into the coronary arteries, and since the heart is relaxed, flow all the way to the muscle of the heart. I don't know if someone has looked into coronary blood flow during these continous pumps, but it might be useful to see, since these hearts are in bad enough shape without becoming ischemic (oxygen starved)

  39. Classic example of creationist dishonesty by Abies+Bracteata · · Score: 4, Informative

    ........ This is not flamebait... lol...

    Well, this is a well-deserved flame.

    ...In fact, run over to your library (bookshelf?) and grab a copy of Darwin's book "On the Origin of Species..." and turn to page 162. Read the section about the mousetrap. Darwin concludes that "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." .....

    Darwin doesn't even mention mousetraps in the chapter from which the individual whose propaganda you are parroting lifted this passage.

    It's pretty clear that calebb is just another not-so-honest creationist who has taken (probably nth-hand) out-of-context a passage from a book he's possibly never even seen. Even if he has seen it, he certainly hasn't read it for comprehension.

    Now, let's look at the rest of that passage, shall we? (emphasis added)

    If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down. But I can find out no such case. No doubt many organs exist of which we do not know the transitional grades, more especially if we look to much-isolated species, round which, according to my theory, there has been much extinction. Or again, if we look to an organ common to all the members of a large class, for in this latter case the organ must have been first formed at an extremely remote period, since which all the many members of the class have been developed; and in order to discover the early transitional grades through which the organ has passed, we should have to look to very ancient ancestral forms, long since become extinct.

    We should be extremely cautious in concluding that an organ could not have been formed by transitional gradations of some kind. Numerous cases could be given amongst the lower animals of the same organ performing at the same time wholly distinct functions; thus the alimentary canal respires, digests, and excretes in the larva of the dragon-fly and in the fish Cobites. In the Hydra, the animal may be turned inside out, and the exterior surface will then digest and the stomach respire

    It's absolutely appalling to see such worthless rubbish like calebb's post here modded up to a score greater than -1.

    BTW, "On the Origin of Species..." can be found in its entirety on-line at http://www.talkorigins.org/faqs/origin.html.

  40. Re:lack of pulsatile flow and coronary vessles by afidel · · Score: 3, Insightful

    Uh, isn't the entire point of these pumps to REPLACE the damaged heart? I mean if you have a low maintenance pump with little chance of failure why are you relying at all on the failing/failed natural heart?

    --
    There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
  41. Re:lack of pulsatile flow and coronary vessles by cellocgw · · Score: 4, Interesting

    Blood will always flow if there's pressure behind it (doh). I'd expect, based more on physics than any experience in cardiology, that a continuous flow at maybe 100mm (well below common systole) would work just fine without overstressing any part of the system.
    But if future studies were to show that a pulsing system really does something useful, it shouldn't be too hard to put a controller chip that has the impeller spin up and spin down at some reasonable rate.
    BTW, just because it's different from nature doesn't mean it's harmful. For example, it may have taken 50 years (largely due to politics) but it's now considered medically safe for women to take continuous contraceptives and go without menstrual cycles for all or most of the year.

    --
    https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
  42. Marine snipers could take longer shots by osjedi · · Score: 4, Interesting

    My pulse is my biggest hurdle when taking high-power rifle shots at long rages (>600 meters). Without a pulse I could hold steady on a much smaller target. If you've never shot a scoped rifle, your pulse makes the crosshairs bounce with each heartbeat. You can slow your heart-rate down and time the beats, but it would still be nice to be able to hold steady on a 1,000 meter target and not have any movement. If you get excited it all goes out the window - if your pulse quickens you might as well be riding on the back of a horse.

    I imagine there are other tasks besides shooting that are impacted by pulse. I'm sure there are types of micro-surgery for example that could be negatively impacted by the surgeon's pulse.

    --
    -=-=-=-=- osjedi uses Debian GNU/Linux. -=-=-=-=-
  43. Mean Arterial Pressure by steelheals · · Score: 5, Informative

    I'll bite: I'm not golfing because I don't have the patience. IAAS (I am a Surgeon) and it would not be that difficult to measure a continuous flow generated pressure instead of a pulsed pressure. Plus you wouldn't have to teach us about turbines and such. For example, currently a patient in the ICU may have their blood pressure measured with an indwelling arterial line rather than a transduced cuff. We follow Mean Arterial Pressure (MAP) in this setting. Here's a quick definition: http://www.globalrph.com/map.htm (It was easier to google than find a textbook but this is short and sweet)- "Equation: MAP = [(2 x diastolic)+systolic] / 3 Diastole counts twice as much as systole because 2/3 of the cardiac cycle is spent in diastole. An MAP of about 60 is necessary to perfuse coronary arteries, brain, kidneys. Usual range: 70-110." We could still measure the equivalent of a MAP with a continuous pump. Some of the bioengineers who commented above probably know better, but whatever the range of pressure in the system from continuous pumping (whether it's always the same or if there's a smaller variation than the normal systolic/diastolic) it could still be accounted for and easily monitored and used to guide therapy. Probably the bigger problems are those already mentioned: baroreceptors that will now be in a new range, changes in coagulation, and destruction of blood borne cellular elements.

  44. A valid fear by The+Tyro · · Score: 4, Informative

    in some countries... I believe China still harvests organs from prisoners.

    In the US there's so much oversight that I can't see it even being possible. Many transplants aren't even done in-house... the organ gets flown to where it needs to go (I've flown on a couple of those... you get to jump to the front of the line on the taxiway, even if there are 30 planes waiting to take off).

    Seriously, there are so many ethical questions, paperwork to be filled out, different physicians involved... declaring someone brain-dead and pulling the plug is a big deal, even more so if it's an equivocal case; it requires multiple physicians to sign off, consultation with the family (and their physician), appropriate consultations and diagnostic testing, and often a review from the hospital ethics committee. Hell, half of the doctors that sit on those committees don't even like one another... they just tolerate each other. There's NO WAY they'd all agree, in some nepotistic star-chamber fashion, to something as evil as wrongfully terminating someone's life and harvesting their organs. No way.

    I can't see that caper ever being pulled off and not coming to light.

    --
    Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
  45. Re:lack of pulsatile flow and coronary vessles by PsiPsiStar · · Score: 3, Insightful

    Perhaps you're right regarding contraceptives and tinkering with human systems, but the reproductive system is one system that can be tinkered with or even removed without too much harm to the rest of the body (re: castrations and all). Especially after puberty. I'm not sure if this is the best proof if you want to make a general argument.

    --

    ___
    It's the end of my comment as I know it and I feel fine.
  46. Re:Chronic bacterial infection? by The+Tyro · · Score: 4, Informative

    No. Your dentist is actually doing the right thing.

    Your dad has a valve problem in his heart, and dental work does cause a transient bacteremia (bacteria being released into the bloodstream). Most of the time your immune system will clear out those bacteria, no problem... most of the time.

    If you have a damaged heart valve, those bacteria can infect the valve, leading to a condition called Bacterial Endocarditis. The bacteria grow on the valve, and can destroy that valve, as well as throwing infected bits downstream in your circulation, leading to brain abscesses, kidney and lung infections, and general sepsis.

    Endocarditis is a nasty, nasty condition... probably most of the cases I've seen were IV drug users. It's a hell of a life; some of those folks will shoot up anything they can find, regardless of what's in it (ie. foreign material loaded with bacteria). Also, when they are re-using needles, the needles will eventually dull, and sometimes barb (painful!). To detect a barb, addicts will sometimes lick the needle tip, then shoot up if no barb is felt with the tongue... you can see where I'm going with this. The human mouth is only slightly less dirty than the human anus... they end up injecting tons of bacteria, and develop Endocarditis. To make matters worse, they never go to the doctor, except when they try to scam more narcotics, or inadvertantly overdose. By the time they do show up, their valves are shot, and they're almost dead. If they survive, they end up needed open-heart surgery and valve replacement.

    Anyway, that's probably more than you wanted to know... but as far as dental procedures go, the antibiotics your dad takes are effective in preventing Endocarditis. He'd be well-advised to keep taking them as prescribed.

    I don't think the original poster was referring to Endocarditis though... I'm fairly sure he was referring generally to Atherosclerotic Disease.

    --
    Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
  47. No pulse.... by thewiz · · Score: 3, Insightful

    As someone who was born with a congenital heart defect, has had three surgeries, and has been ticking with an artificial valve for the last 22 year, I'd be worried about not having a pulse.

    One of the things doctors/surgeons have noticed with heart patients that have their hearts stopped is that they lose all sense of time. I noticed it after my surgeries. I don't know if anyone has done research into the beating of the heart and the mechanisms in the brain that allow us to perceive the passage of time. Does the beat of the heart interact with the area(s) of the brain that perceive the passge of time? Do other bodily processes require a heartbeat for a "timeing signal"? I'm sure there are other questions to ask about this subject.

    Show me a man with a song in his heart and I'll show you a man with an AM/FM pacemaker!

    --
    If "disco" means "I learn" in Latin, does "discothèque" mean "I learn technology"?