Jonathan Edwards
"Gibberish"
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Interesting. Doctors tend to get very muddled about this sort of physiology. I am fairly sure that high protein levels do not increase blood volume in fact. This is an old theoretical idea based on a misconception about Starling's Law that may be best forgotten. As zzz points out, an autonomic dysfunction with venodilatation - as occurs with some peripheral neuropathies for instance will tend to lead to an increased blood volume but, crucially, this volume will seem to be too low, especially if you stand up. This is because the capacity of the 'bag' of the circulation has increased, maybe even more than the blood volume has increased. What people call hypovolaemia often means relative hypovolaemia, which could easily be absolute hypervolaemia, I think.
So what actually matters for symptoms is whether or not the blood volume fits the size of the circulation bag. In heart failure there is too much blood for the bag. If you sit up some of the plasma leaks into the feet and you feel better but when you go to bed that all drains back to the circulation bag and you wake up short of breath again.
So I am not actually sure that measuring blood volume itself is necessarily much help - at least not on its own. What you want to know is if the volume is enough for your circulation. That you can tell quite easily in a physical examination by looking at the central venous pressure - CVP. A precise measure of CVP requires equipment but a simple and pretty reliable way is to lie the person down and look at the neck veins when you press on the abdomen to squeeze blood out of the venous pool there. If blood volume is higher than ideal the neck veins are full to start with. If it is low they do not even fill when you press on the abdomen. There is a strange exception to the rule in constrictive pericarditis where you want the volume to be relatively high to ensure enough blood gets into the tight pericardium.
My suspicion is that this is all the same thing in ME - autonomic dysfunction with both relative and absolute shits in volume.
So what actually matters for symptoms is whether or not the blood volume fits the size of the circulation bag. In heart failure there is too much blood for the bag. If you sit up some of the plasma leaks into the feet and you feel better but when you go to bed that all drains back to the circulation bag and you wake up short of breath again.
So I am not actually sure that measuring blood volume itself is necessarily much help - at least not on its own. What you want to know is if the volume is enough for your circulation. That you can tell quite easily in a physical examination by looking at the central venous pressure - CVP. A precise measure of CVP requires equipment but a simple and pretty reliable way is to lie the person down and look at the neck veins when you press on the abdomen to squeeze blood out of the venous pool there. If blood volume is higher than ideal the neck veins are full to start with. If it is low they do not even fill when you press on the abdomen. There is a strange exception to the rule in constrictive pericarditis where you want the volume to be relatively high to ensure enough blood gets into the tight pericardium.
My suspicion is that this is all the same thing in ME - autonomic dysfunction with both relative and absolute shits in volume.