Now that I’m selling my soul*, I’ve begun to wonder.
I have very, very large veins, it’s a family trait. They’re like ropes, I tells ya. But after having over a pint of blood drawn from my arm and pumped back in, the vein it was taken from doesn’t seem as prominent as it was before. Is this a permanent condition caused by giving blood or injecting fluids? Or does it just seem smaller because of a tiny yiddle scabbie over it? Is it smaller because of trauma at the point of needle entry? What causes heroin addicts’ veins to collapse? Is it life threatening? If a vein collapses, how does blood circulate freely through the extremity?
I’m not worried (imagines humongous needle coming towards neck), my interest is simply piqued.
Trust me, you don’t get collapsed veins from giving a single pint of blood.
If you really want to know all about collapsed veins, just think–there you are, sitting in front of a computer, with the entire Internet at your disposal.
But I’ll bet a nickel that by the time you read this, the vein in question will be back the way it was.
Arteries are blood vessels that travel from the heart to the body. Veins are blood vessels that go from the body to the heart so it can be re-oxygenated by the lungs.
You know this. So what?
Well, the heart only supplies so much blood pressure. SO arteriers are quite elastic in order to conserve energy like those collisions you studied in high school physics. Arteries have a palpable pulse.
Veins act as a storage place for blood. They are not elastic and collapse when not actively perfused. They could not store blood if they were elastic.
Giving blood might cause a short term collapse of veins near the withdrawal site. Not for long in a young person.
Ahhh, DDG, I’m not worried one bit. It just got me to wondering why donors don’t get collapsed veins, and junkies do. How does blood circulate in a vein system that is collapses?
And, also, how much ‘extra’ saline, blood, plasma, whatever, could be pumped into a person before their circulatory system couldn’t handle the extra load? Let’s say you pump an extra 2 pints of .9% saline into my veins, what happens?
Junkies get collapsed veins because they poke themselves repeatedly in the same place with dull needles. Eventually the vein wall can’t take it anymore and goes flooey.
As I understand it, it’s not the entire vein system that collapses. It’s more like a hole in the side of a garden hose. It leaks but is still serviceable. I believe varicose veins are a kind of collapsed vein, and I’ve never heard of anyone dying from varicose veins.
Also, repeated trauma causes the vein walls to become scarred (sclerosed). This happens in chemo patients, both from trauma of getting stuck so many times and because the chemicals are fairly harsh on the endothelium (lining of the blood vessels).
Blood circulates in collapsed veins for two main (related) reasons: veins have a series of one way valves to minimize backflow, and the muscles act as a pump to push on the vein, forcing the blood back to the heart.
The venous system can store lots of blood. I think the limiting factor is usually how much blood can the heart pump. Having too much fluid can lead to Congestive Heart Failure or pulmonary edema. The amount would depend on the person. One of the best ways to diagnose CHF is to look at the jugular vein in the right neck triangle. The more it is distended above the level of the collarbone, the worse things are.
lets see if I remember this right, JVD would be a sign for right sided CHF – if the patient was experiencing left sided CHF that would cause pulmonary edema.
I was under the impression that one (left vs right) rarely happens independently from the other, just one side seems to be more severe than the other, and that right sided seems to be the more prevelient one…
Left heart failure is more prevalent, but when it goes, the right heart goes too, causing JVD, and hepato-jugular reflux also. Both are bad, but when the left heart goes, blood backs up in the lungs, making oxygen exchange difficult, causing pulmonary edema, which soon overloads the right heart, trying in vain to push against an increasing gradient, and then blood backs up into the vena cava. Right heart failure can occur in isolation, but it’s not common
Cardiologists have this annoying habit of repeating the same hackneyed phrases… “Time is muscle”, “Mediterranean diet”…
… and “The most common cause of right heart failure is left heart failure”. You’re right. Cor pulmonale (right heart failure due to the backflow from the lungs with a good left heart) is rare.
Just mentioned JVD since it is the most obvious example of venous overstorage. In essence, veins feed into the right atrium which lacks a valve, hence blood that is not pumped by the heart in essence flows back into the jugular vein.
Wouldnt an AMI causing death to the right side of the heart (and not death of the patient) be a cause for right sided CHF? Are there any stats for an AMI leading to CHF and which side devlopes first?
Med school is 2 years back (middle of grad school now) but I’ll bite :
Right sided heart failure is pretty well tolerated. You can even use the pulmonic valve as a replacement for the aortic valve without putting anything in place for the pulmonic valve. AMI can of course cause CHF, but not usually through right sided failure.
“AMI can of course cause CHF, but not usually through right sided failure?”
Is that because the AMI’s generally occur due to the blockage of the cornary arteries that feed the left side of the heart? Are blockages of the arteries that feed the right side of the heart much less uncommon? Do blockages (aside from the major coarnary artiers, they are just plain deadly) of the right side cause death more often, leading to left sided failure because patiends do not survive the event that would lead to right sided failure?