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The human heart can pump the body's entire volume of
every single minute - and not just in a straight line, but
through a maze of twisty passages, all different.
Most cardiac assist and heart replacement devices try to
inside the chest, and there's not a lot of room in there.
propose a group of stent-like devices placed at strategic
inside various larger arteries (e.g., ascending &
aorta, the carotids, others) where each would take up
space than a complete heart replacement - but each
only have to move a smaller volume of blood than the
handles by itself. As blood is salty enough to conduct
electricity, the stents could be tiny
accelerators; non-mechanical pumps to avoid damaging
Haven't quite worked out a power supply though (nuclear
battery?); what field strength would be required;
if having one or more such devices in the body would
problems more serious than getting through airport
[kdf, Oct 30 2020]
Ventricle assist devices
Many are continuous flow, pulse-less [kdf, Nov 01 2020]
Possible side effect of magnetic fields on blood
Favorable - reduced viscosity? No need for anti-coagulants. [kdf, Nov 02 2020]
MHD pump applications
[kdf, Nov 02 2020]
Wikipedia article mentioning induction devices
Might sole electrolysis problem [scad mientist, Nov 03 2020]
Shape memory alloy - cardiac assist
Technical Feasibility and Design of a Shape Memory Alloy Support Device to Increase Ejection Fraction in Patients with Heart Failure [kdf, Nov 03 2020]
The game emulating human survival. [Inyuki, Nov 04 2020]
Procyrions intra-aortic pump
[kdf, Nov 04 2020]
Wireless heart pump
Wraps around the outside of the aorta [kdf, Nov 04 2020]
||This could be used in conjunction with a g-suit to enhance the performance of combat pilots. [+]
||"could be used in conjunction with a g-suit to enhance the
performance of combat pilots"
-8th of 7, Oct 30 2020
||[previous rambling about veins removed]
[replacement text: You're right. I was only thinking of
arterial stents originally. But venous stents would be
possible also. Good one!]
||Side note - I specifically thought of the Borg when I was
cooking this one up. Is there any place in ST canon where
Borg technology has been used for human medical
||Pertinax - "A magnetohydrodynamic drive or MHD accelerator
is a method for propelling vehicles using only electric and
magnetic fields with no moving parts, accelerating an
electrically conductive propellant (liquid or gas) with
magnetohydrodynamics." Source: Wikipedia (linked)
||// Borg technology has been used for human medical treatments? //
Yes, of course, in the Voyager episode ... wait, you mean you don't KNOW ?
||What sort of a Trekkie are you ?
||Not any sort of Trekkie. I have a broad base of knowledge but
not very deep in some areas. As with all other things, I consult
experts when necessary. Please, expound on the theme of
applied Borg technology (short of assimilation) in human
||Given that the total length of an adult's blood vessels is
better than 60,000 miles (over twice around the earth) some
assists here and there make sense.
||Additionally for every pound of fat another mile of vessels
are required, an additional strain on the heart.
||"for every pound of fat another mile of vessels are required"
-whatrock, Oct 30 2020
||An interesting detail but one I would question. Do the blood
vessels get discarded or put in storage if I lose weight, or do
they just shorten if the distance between various body parts
shrinks? And what about going the other way, bulking up by
adding muscle mass? Does muscle growth require new
mileage of blood vessels, or stretching existing ones?
||Angiogenesis, the second book in the bible.
||//a dark maze of twisty passages, all different.// -
nice 1970s text adventure computer game
||There is a relationship affecting the heart stroke and power with the factors of capacity and stretch of the volume coming out in the maze. Playing about with a few extra tiny asynchronous pulses will take some work to get the supplementary pumps timed just right.
||Because of complexity, I wouldn't put it past the body to have heart cells that alter slightly depending on the biochemistry of the pulse volume. I wouldn't want to see biochemical signals negated or changed by mechanical wave fronts.
-wjt, Nov 1 2020
||No. These would offer a continuous flow, rate
changing constantly based on the bodys needs. No
pulse at all. This is already the case with some
existing ventricle assist devices (link).
||//blood... magnetohydrodynamic accelerators...//
That's quite brilliant. Have there been any (real-world)
experiments with this? Blood, being somewhat more
complicated than just salt water, might not like being
subjected to strong e-m fields...
||Yep, needs more research. But likely no worse
than mechanical devices in use now. Do the fields
used in MRI - whole body exposure - mangle blood
cells or affect circulation?
||No, and they're several Tesla ... many orders of magnitude stronger than anything encountered by humans in a natural environment.
||Oh well... heres a showstopper for using MHD to
move blood: Electrolysis. From link reviewing
MHD pump applications ...
||Conducting fluid in the micro-channel of MHD
micropump was studied by Jang and Lee. The
micropump is driven by Lorentz force in the
direction perpendicular to both magnetic and
electric fields. The performance of the micropump
is obtained by measuring the pressure head
difference and flow rate as the applied voltage
changes from 10 to 60 VDC at 0.19 and 0.44 T (T).
The pressure head difference is 18 mm at 38 mA
and the flow rate is 63 μl/min at 1.8 mA,
inside diameter of inlet/outlet tube is 2 mm and
the magnetic flux density is 0.44 T. It was noted
that bubble generation by the electrolysis of the
conducting liquid can be observed.
||... back to turbines, I guess...
||The Wikipedia article mentions induction devices that
may solve the electrolysis problem: "Induction devices
when alternating currents are induced by a rapidly
varying magnetic field, as eddy currents. No electrodes
are required in this case.
As induction MHD accelerators are electrodeless, they do
not exhibit the common issues related to conduction
systems (especially Joule heating, bubbles and redox
from electrolysis) but need much more intense peak
magnetic fields to operate. Since one of the biggest issues
with such thrusters is the limited energy available on-
board, induction MHD drives have not been developed out
of the laboratory."
||One might expect the power requirements to be a
problem, but you mentioned nuclear battery, so we
should be good, right :)
||Also, without really researching this, I'm imagining that
this type of device can clamp on around the outside of
the blood vessel so there might be less risk during
||The problem with clamping to the outside of the
blood vessel is that installation requires more
surgery from the outside. Stents are installed via
catheter, much less invasive or damaging to
||This idea is even less than half baked so Im open
to suggestions for changes, but the idea of stent-
like devices was really the root of it. Turbines
instead of MHD, sure; alternatives to nuclear
power, Im all ears. But you shouldnt have to cut
the patient open in multiple places.
||Nononono, very bad. We see dead people. Dialysis and heart-lung machines invariably use peristaltic pumps - putting blood through any sort of a turbine will severely limit your life expectancy.
||Turbines arent my first choice either, but theyre
pretty common in existing pulseless VADs. I still
though, as I think it could produce laminar flow,
and be less damaging to blood cells. But if you
insist on a pulse... How about a coil or mesh tube
Give it a charge at one end, and a wave-like
ripple/contraction proceeds along its length before
relaxing back into its original profile? Can it be
made small enough to fit inside the aortas and
carotids? And biocompatible so the patient isnt on
anticoagulants and immunosuppressants? And a
useful service life of 10-20 years?
||Ill need your design spec before the 17th, so I can
discuss with my cardiologist.
||See, there really are no "new" ideas. *AFTER* I
about shape memory alloys, I found (link)
close to what I was thinking of - but wrapping the
instead of inserting something in blood vessels. I
wonder if I read that paper or a citation to it
somewhere before and just
didn't recall it properly.
||What about a piezo-plastic tube working as a peristaltic
pump? Could be inside or outside the blood vessel (inside =
easier, outside = cleaner/safer for the blood).
I don't know how flexible piezo-plastics are, but I figure if
it's small enough, it doesn't matter. And if it's just a single
material doing the work, it can be scaled down pretty small
(à la integrated circuits).
-scad_mientist, Nov 03, 2020
||... require alternating current and and much more
intense peak magnetic fields to operate.
||Is your idea inspired by the game of [Shapeflow]? (link) :) What you speak
of, seem to
be a result of thinking how to win that game. Good thinking [+].
Imaginably, those little
assists around the body could do even more -- they could: absorb stuff
and dissolve stuff, warm, cool, and do other things to ensure uninterrupted
||Inyuki - No, Ive never heard of Shapeflow. This HB
post came from a long riff about how far medical
technology might go ... from repairing/replacing a
heart valve, to more involved repairs, to making
the heart itself redundant.
||//Dialysis and heart-lung machines invariably use
peristaltic pumps - putting blood through any sort of a
turbine will severely limit your life expectancy.//
||That's possible, but it's also feasible to design around
that. The reason for using peristaltic pumps is much more
to do with the fact that the blood remains entirely within
a continuous stretch of disposable tubing the entire time.
Sterilizing moving parts like impellers would be a
nightmare. Out of interest, is the heart a peristaltic pump
or a diaphragm? I'd go with it being a hybrid.
||I have some Doppler recordings of blood flow with a
marker of muscle contraction. To me it's obvious the
heart muscle isn't doing anything for the last ~10% of each
beat and the last part is sucked out of the ventricle
through inertia/water hammer. I'd publish it if I had
time/it benefited me in any way/I had any credibility in
the field/publishing didn't cost a fortune.
||Maybe I'm going the wrong way with this. Veins have one way
valves and any muscle action squeezes blood back towards
the heart. Let's just* modify some of our larger arteries to
do the same for outbound flow.
||* By way of gene splicing** - or microsurgery - or hand waving
||** Genes from an earthworm and our aorta can
be powered like theirs.
||Link - Pumps Inside Arteries Help Cardiac Patients" - from
2014. And once I found that, I found links for other related
ideas we tossed about here.
DON'T YOU IT WHEN THAT HAPPENS?