4 ms·

why is it risky?

by buryat 4y ago

why is it risky?

PeterisP 4y ago
You need to treat lots of blood continuously, so you have to cut a bypass into the largest, irreplaceable blood vessels, unlike smaller operations like kidney dialysis where you can just "plug into" an arm. Mechanical pumping of blood is a problem as it damages blood cells. Infection is a severe risk. Any break in the operation or a temporary "plumbing issue" where the machine connects with the body can be fatal. So you need 24/7 monitoring capable of really rapid response.
tibbydudeza 4y ago
Red blood cells are meant to travel into capillaries so must deform but will shear easily when subjected to stress which activates clotting action - mechanical pumps still cannot replicate the pumping action of heart.
- gxt 4y ago
  How has medical science never heard of bellows? https://en.m.wikipedia.org/wiki/Bellows https://en.m.wikipedia.org/wiki/Bellows
  - tibbydudeza 4y ago
    Heart is truely an amazing organ - don't think we will get close to a mechanical replacement. Has multiple chambers, Has chambers that pump sequentially with different pressures and volumes, Never needs to stop for additional lubrication, Never needs to be "charged", Never stops for maintenance, Is powered by oxygen delivered by the red blood cells it is pumping, Is controlled by the body's "proprietary" electro-chemical control system, Is not rejected by the body's internal bio-chemical defense mechanisms, Produces only carbon dioxide as waste, delivers that waste to red blood cells, Doesn't have a single rough or chemically reactive surface, Forms perfect in-line seals around each chamber without crushing red blood cells, Never leaks a single drop, Doesn't retain any fluid in the chambers, Doesn't allow "backward" flow, Has a pump action and pressure that are strong enough to circulate blood up from your toes, but delicate enough to prevent damaging any red blood cells or capillaries
    - gxt 4y ago
      I don't care how amazing the body is (it is), blood flow needs constant flow with a pulse. Put two bellows in parallel, use a linear motor to push out quickly and pull in slowly on each, and voilà mechanical heart without shear. MIT licensed, go save lives you f'ers.
      - ceejayoz 4y ago
        People with a LVAD don't have a pulse, actually; it's not required. https://en.wikipedia.org/wiki/Ventricular_assist_device https://en.wikipedia.org/wiki/Ventricular_assist_device
      - tibbydudeza 4y ago
        In a suitcase ???.

why is it risky?

by buryat 4y ago

why is it risky?

You need to treat lots of blood continuously, so you have to cut a bypass into the largest, irreplaceable blood vessels, unlike smaller operations like kidney dialysis where you can just "plug into" an arm. Mechanical pumping of blood is a problem as it damages blood cells. Infection is a severe risk. Any break in the operation or a temporary "plumbing issue" where the machine connects with the body can be fatal. So you need 24/7 monitoring capable of really rapid response.

tibbydudeza 4y ago

Red blood cells are meant to travel into capillaries so must deform but will shear easily when subjected to stress which activates clotting action - mechanical pumps still cannot replicate the pumping action of heart.

gxt 4y ago
How has medical science never heard of bellows? https://en.m.wikipedia.org/wiki/Bellows https://en.m.wikipedia.org/wiki/Bellows
- tibbydudeza 4y ago
  Heart is truely an amazing organ - don't think we will get close to a mechanical replacement. Has multiple chambers, Has chambers that pump sequentially with different pressures and volumes, Never needs to stop for additional lubrication, Never needs to be "charged", Never stops for maintenance, Is powered by oxygen delivered by the red blood cells it is pumping, Is controlled by the body's "proprietary" electro-chemical control system, Is not rejected by the body's internal bio-chemical defense mechanisms, Produces only carbon dioxide as waste, delivers that waste to red blood cells, Doesn't have a single rough or chemically reactive surface, Forms perfect in-line seals around each chamber without crushing red blood cells, Never leaks a single drop, Doesn't retain any fluid in the chambers, Doesn't allow "backward" flow, Has a pump action and pressure that are strong enough to circulate blood up from your toes, but delicate enough to prevent damaging any red blood cells or capillaries
  - gxt 4y ago
    I don't care how amazing the body is (it is), blood flow needs constant flow with a pulse. Put two bellows in parallel, use a linear motor to push out quickly and pull in slowly on each, and voilà mechanical heart without shear. MIT licensed, go save lives you f'ers.
    - ceejayoz 4y ago
      People with a LVAD don't have a pulse, actually; it's not required. https://en.wikipedia.org/wiki/Ventricular_assist_device https://en.wikipedia.org/wiki/Ventricular_assist_device
    - tibbydudeza 4y ago
      In a suitcase ???.