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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?"
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.
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
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.
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.
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.
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.
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.
Well, this is a well-deserved flame.
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.
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
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.
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.
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.