*In the following text I’m gonna try to explain the subject a bit to make the question accessible to those who don’t have any kind of knowledge about this, and to clarify my points to those who do know what im talking about (I apologize, it’s long, but this is not an easy problem lol):*
So every single organ and body part is fed with a constant stream of blood by at least one major artery and one major vein.
What leaves me confused is, they obviously cannot just sew the vessels closed because arteries are like insanely pressurized and the venous system relies on that small bit of pressure that is left from the arteries to help push the blood back up towards the heart. If they just took away the organ/limb and cut the artery and the vein and sewed them shut the pressure in the artery would cause it to burst and the closed vein would have no new imputs of blood to push the rest up, resulting in stagnant blood from the vein and a massive internal bleeding from the artery and the patient is dead.
Also they can’t even remove the whole artery and vein cause:
a) every major artery comes from a huge artery that runs through the center of your body called the Aorta, which is like an inch thick and carries *insanely* pressurized blood. You would therefore have to go up to the Aorta to eventually be able to cut off the artery from its beginning to avoid pressurized blood going into it in the first place, but any rupture or cut of that proportions in the Aorta would definitely cause a massive bleeding. Same thing with veins, every major vein ends up in two *gigantic* veins called the Caval Vein and the Portal Vein, that would most likely have the same catastrophic and very deadly outcome.
and b) each of those arteries and veins feeds a ton of other stuff and organs and tissues along its way to its primary organ, which would all go necrotic and cause the patient’s death.
After considering all this I thought the only logical solution would have to be to take the cut end of the artery and the cut end of the vein and sew them together, so that the blood from the artery just bypasses the missing organ and goes directly into the vein, but this carries a major problem: pressure.
Arteries are literally made to withstand the pressure the blood has after being forcefully squished out of the heart, but veins are not, as when blood gets into them it’s not pressurized anymore. This happens thanks to the capillaries: to go from an artery to a vein blood has to run through a huge net of tiny little vases that actually feed the tissues and that slow down the blood, being so narrow that blood cells can barely squeeze into them and when blood comes out of them it’s not pressurized anymore.
Veins are actually really elastic cause they have to constantly adjust to the volume of blood that is moving in your body: the most bloode you use, the more the venous pressure goes up, the more the venous system gets bigger in volume.
Therefore, attaching the pressurized artery to the very elastic vein would be like filling a big ass elastic balloon with blood from a fire hose, again eventually causing rupture and internal bleeding and killing the patient.
So people who do know the answer, please, I beg you, enlighten me cause I can’t live without knowing this anymore lmao
In: Biology
Amputation is one of the rarer of many procedures that involve ligating or “tying off” an artery. It’s obviously not completely benign and has the potential to cause issues, but it’s possible thanks to the adaptability of our bodies. Blood vessels can reorganize themselves in situations like this – the closest to an official name for this process I’ve heard of is “vascular remodeling,” though it doesn’t seem to be referred to by this term all the time. Vessels can even generate new branches to spread the blood supply as needed. As far as I’ve read though, ligating vessels is a complicated step of amputation surgery in order to assure adequate blood supply and minimal bleeding, and every residual limb will be different.
The “blood vessels” section here explains some of this and the related potential complications:
https://orthop.washington.edu/patient-care/limb-loss/general-principles-of-amputation-surgery.html#vessels
Tying off an artery is not like trying to plug a garden hose with your finger. It’s more like turning off the tap on your kitchen sink. The water supply to your house is connected to the municipal water system, which brings pressurized water into everyone’s homes and businesses. When you turn off the tap that pressure doesn’t go away, but it redistributes to every open tap in the network. There are so many of these that the change is negligible.
When you tie off an artery I suppose you cause a slight pressure increased elsewhere in the vascular system, but this is well within the body’s ability to compensate for. Isolating and ligating the blood supply is usually one of the first steps in removing an organ.
Assuming you go low enough, once you hit a certain level, the arteries that feed into our limbs really only do that. The blood supply for our major internal organs has a different branch point. You can in fact oversew the cut artery and vein without either at overly high risk of bursting. There are still plenty of capillary connections between the arterial system and the venous system to make it work without the capillaries and smaller arteries and veins lower down.
Keep in mind that capillaries do not all simply branch from the end of the major artery. Smaller arteries break off from the main artery at various points, each of these breaks off into numerous arterioles, which each branch off into a bunch of capillaries at various points. These then come back together into venules, which collect together to become small veins, which collect together into larger veins and so and and so forth. If ligated correctly, the flow is not at risk of bursting the wall of the vessels because it will simply take the path of least resistance and flow into the smaller vessels
Your entire concept of the circulatory system is wrong. You are thinking of it like a highway system where there is some central path and all the other organs just have off ramps to siphon off some blood. Blocking the main path would seem to cause the huge problems you mentioned.
Except it isn’t like that at all. Instead think of the main output from the heart being split, and then split again, and split again, etc. until all you have is blood oozing through tiny capillaries and the tissue itself. If you block off one of those paths then obviously anything fed from that path will have trouble, but pressure isn’t really going to “back up” behind it because there are plenty of other routes to follow.
Another point is that the aorta and arteries really aren’t *that* pressurized. The “insane pressure” is actually only 2-3 psi. That is well within the range of sewing it shut and letting it heal.
It really is a matter of just cutting the arteries and veins at the point they are entering the organ and sewing them shut (called “ligating”). You’ve got a few things right, but a few other misconceptions that I think are causing you to overthink this. Arteries are not “insanely pressurized”, but even if they were, closing one off is not going to have much effect. If you think of it as plumbing, the blood will just flow through all of the other arteries instead of through the now dead end one. Veins are also not pressurized by the heart. Capillaries are so small, that the veins don’t ever “feel” the pressure of the heart pumping. You mention that veins are elastic, and arteries are too to some degree. This allows them to respond to any (small) increase in pressure by suddenly having roughly the same amount of blood circulating through a slightly smaller plumbing system when you tie off an artery.
source: am surgeon
They sew them shut and it’s fine. The blood just stops flowing and the vessel doesn’t explode or anything.
Surgeons don’t usually connect an artery to a vein, unless they are trying to create a fistula for hemodialysis access, usually in the arm. The vein does enlarge quite a bit to create an easy place to place the catheter to the dialysis machine.
If it gets too big sometimes it’s a problem then they do another operation to decrease the blood flow.
Source: I watched a lot of vascular surgeries and amputations.
Just want to say awesome answers from so many people, very informative!
My personal experience: I have no spleen. It was splattered in a car accident, there was nothing left so everything got sucked out. To my understanding, they cauterized my splenic artery. Then while in recovery, it somehow came open & filled my stomach with blood, so they went back in & fixed it. I’ve had weird pains from time to time that are like symptoms of something wrong with your spleen (pains in certain areas). I call it my “phantom spleen syndrome”, that’s the only explanation I’ve kind of been given for it. I’ve been told it’s like a blood flow gravity thing, I don’t know. It was 13yrs ago & it doesn’t happen often anymore, just digestive issues now from having no splenic flexure in my colon (because there’s no spleen for it to attach to, so it sags instead of curves).
We ligate the blood vessels first then cut. Sometimes, based on the instruments, this is the same process.
Ex. Hysterectomy- removing the uterus
First you need to know all the points of blood supply: uterine arteries, arteries of Samson, utero ovarian ligaments.
Each of those needs to have blood supply identified and ligated/stopped.
Arteries of Sampson are small so we could use an instrument like a [Ligasure](https://www.google.com/search?q=ligasure+device&tbm=isch&ved=2ahUKEwj88KCF2Z7vAhWjSt8KHU_ZAXwQ2-cCegQIABAC&oq=ligasure&gs_lcp=ChJtb2JpbGUtZ3dzLXdpei1pbWcQARgBMgIIADICCAAyAggAMgIIADICCAA6BwgjEOoCECc6BAgAEEM6BAgjECc6BQgAELEDOgQIABADUNiIhwRY_rSHBGDXw4cEaAJwAHgAgAGDAYgB8gWSAQM2LjKYAQCgAQGwAQXAAQE&sclient=mobile-gws-wiz-img&ei=4wtFYLzzHqOV_QbPsofgBw&bih=640&biw=375&prmd=minv&rlz=1CDGOYI_enUS838US839&hl=en-US#imgrc=jU2mYVj8_tGMAM) which uses electricity to do a controlled burn and coagulate/solidify blood supply before cutting it. If the blood supply is small, we can coagulate and cut in the same place. If the blood supply is larger, such as on the utero ovarian ligaments, you may pick a spot to cut but use the Ligasure to burn/coagulate on either side of where you’re gonna cut. This gives a back stop so that, even if the point where you cut leaks, then there’s the backstop/backup points to prevent bleeding.
Now you get down to the uterine arteries which are pretty significant blood vessels. You may not want to rely on the Ligasure because the vessel is too big. In this case, you passed a suture string around the blood vessel on either side of where you want to cut, you tie a really really tight knot there. This pinches shut the blood supply, so, again you can cut in a spot that won’t bleed.
After the structure/organ has its blood supply controlled, you can remove it from its other attachment sites.
The other attachment sites with less prominent blood supply can be controlled with the electric coagulation in points or with area specific suturing.
If you are transplanting an organ, you probably don’t want to burn its attached blood vessels, so the latter example would be preferable.
While we’re at it, what do they do with the limbs?
Not sure if this helps… after my CABG, they literally cauterize the place they grafted the arteries from. 1 from my leg. 1 from my right pectoral.
Hurts like a mofo. More than having all of my ribs broken.
Here’s some light reading:
https://mmcts.org/tutorial/1280
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