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how does one test for low blood volume?

Discussion in 'Problems Standing: Orthostatic Intolerance; POTS' started by anniekim, Nov 27, 2011.

  1. anniekim

    anniekim Senior Member

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    I think I remember reading in Corinne's excellent blog series about her treatment with Dr Peterson (my computer won't let me open some of the entries, so can't read it back) that Dr Peterson tested her low blood volume. Can someone share is there a test for low blood volume and if so what does it entail?

    Many thanks in advance
    Bradford likes this.
  2. heapsreal

    heapsreal iherb 10% discount code OPA989,

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    try taking your blood pressue lying down and then again when standing for minimum 10 mins if there is a big difference >20, this can give u an idea of hypotensive POTS where your blood pools in your boots, also if your pulse increases as well when standing, sometimes heart rate increases to compensate for low blood pressure. If both lying and standing BP is below 100/- then u would be classed as having hypotension and u would feel like crap especially standing up, dizzy , nausea etc. As well as POTS treatments look into a good iron supp and b12 as being anemic can also cause low BP.

    cheers!!
  3. Sushi

    Sushi Moderator and Senior Member Albuquerque

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    There are specific tests but they will only be offered at hospitals that take a special interest in autonomic dysfunction (low blood volume being related). Vanderbilt offers this test but I can't remember how they actually do it.

    If you look on the website and forum http://potsplace.com/, you are likely to be able to dig up the details.

    Best wishes,
    Sushi
  4. anniekim

    anniekim Senior Member

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    Thanks for the replies

    Heapsreal, sorry bit confused. Your recommendations sound like testing for OI/POTS. Is low blood volume always synonymous with OI? Thanks
  5. heapsreal

    heapsreal iherb 10% discount code OPA989,

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    I suppose it is for POTS, but also a low blood pressure can indicate low blood volume. People in hypovolaemic shock, which is a large blood loss, generally have a fast pulse rate to compensate for their low blood pressure from blood loss. This is coming from my experience in emergency medicine. There are different types of shock as well, cardiogenic where the heart pumps inefficiently, distributive which is generally from spinal injuries, septic shock from an infection/s, and anaphylaxis. All of these lower your blood pressure in some way and hypovolemia is from low blood volume. These are the common forms of low BP/blood volume in emergency medicine but i think there can be a cross over between these and chronic conditions.

    I think distributive shock similar to spinal injuries could be similar but in a more minor way to hypotensive POTS/OI especially those with EDS as they have a loss of vascular tone to maintain a descent blood pressure. a normal blood pressure is needed to maintain cerebral circulation, to higher BP can also hinder cerebral circulation as well.

    Working as a paramedic involves the basic DRABC but also maintaining good blood pressure and cerebral circulation, so hypoxia and cell/brain death/injury is minimised, thats the nuts and bolts anyway. I just mention this so you know where im coming from, but emergency situations are also different to chronic conditions but considerable overlap. I also mentioned iron and b12 supps to as if anemic this can lower BP and blood volume as well, this is normally picked up on routine blood tests.

    cheers!!
  6. richvank

    richvank Senior Member

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    Hi, anniekim.

    There are two methods of which I'm aware. One is done in nuclear medicine departments of hospitals. A known volume of blood is drawn, and is labeled with a radioactive isotope. The blood is put back in and allowed to mix with the blood in the circulation. Then another blood sample of known volume is taken, and the radioactivity measured. By evaluating the ratio of the radioactivity in the original, labeled sample to the radioactivity of the sample drawn later, it is possible to calculate the total blood volume by multiplying this ratio times the volume of the first blood sample. There are two variants of this. One is used to measure total red blood cell volume, and the other to measure the plasma volume.

    The other approach uses a dye rather than a radioactive tracer, and the dye is measured with a spectrophotometer. The same type of ratio calculation is done.

    Best regards,

    Rich
  7. heapsreal

    heapsreal iherb 10% discount code OPA989,

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    How would one go about getting a test like this. I think it would be a struggle to get, as most hospitals see cfs as a psych condition, especially the UK. Do the cfs gurus like peterson or klimas do testing like this, may be an option.
    Is there any other way that would be cheap and convenient?? Maybe different postural BP checks with checking red blood cell counts/haemoglobin etc, just a guess stab in the dark.
    Just thinking of other conditions like diabetes insipidus, chronic diarrhoea/ IBS etc could lower blood volume by causing dehydration, probably many others too.

    cheers!!
  8. Emootje

    Emootje Senior Member

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  9. richvank

    richvank Senior Member

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    Hi, heapsreal.

    I do think that POTS and OH in ME/CFS result at least in part from low blood volume, but I think you have to actually evaluate blood volume to know if it is low.

    The problem with measuring RBC and hemoglobin is that these are "per unit blood volume" measurements and don't tell you what the total blood volume is. It appears that the kidneys, via regulating the secretion of hematopoeitin, adjusts the production of red blood cells to match the total plasma volume, so these parameters tend to stay normal, even though the total blood volume may be low. This is important for maintaining the viscosity of the blood.

    This new machine that Emootje posted about looks like a more convenient way to do the blood volume measurement.

    This type of measurement is sometimes done during a surgery, to determine whether the patient needs a blood transfusion.

    There is a dye-based machine developed in Japan, I think, but I don't know if got FDA approval for use in the U.S. I know that Dr. Julian Stewart was testing it a few years ago.

    Best regards,

    Rich
  10. heapsreal

    heapsreal iherb 10% discount code OPA989,

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    Just trying to think outside the box for something cheaper and easier to do/measure. What about a simple monitoring of fluid input versus fluid output, maybe over 2 days. This could measure if your taking in enough fluid which then can have a bearing on blood volume etc. Im thinking that if someone doesnt have access to the new technology maybe some simple at home tests could be enough proof for someones doctor to then refer them onto a hospital with this sort of technology. I think just saying u have low blood volume to a doctor isnt going to hold much weight but a few simpler tests might make him think twice. Also like u mentioned rich, could also pick up other abnormalities in kidney function etc. Its an interesting subject.

    cheers!!
  11. richvank

    richvank Senior Member

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    Hi, heapsreal.

    One thing that's cheap and easy to do is to measure the 24-hour urine volume. The normal average value is 1.5 liters. If it's a whole lot more than that in a person who has ME/CFS, it's likely that they have diabetes insipidus, and if so, it's also likely that they have low total blood volume. Even though they are always thirsty and they drink a lot of fluid because of their thirst, they don't actually keep up with the loss of water into the urine, so they have hypovolemia (low blood volume).

    Best regards,

    Rich
  12. CBS

    CBS Senior Member

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    Hi Rich,

    I wanted to second your comments and add a couple points that I found important. First, in my experience, fluid loss leading to hypovolemia can be episodic (some 24-hour urinary volumes in the 1500-1800 ml range and others the same weeks being over 4000 ml). However, if you lose enough fluid (even in brief 2-4 hour episodes), it can be tough to counteract it with fluid intake and the result is nearly constant but varying degrees of hypovolemia. Secondly, some doctors will substitute hematocrit levels as a measure of dehydration. Dan Peterson did a small study several years ago that found hemaocrit levels in hypovolemic CFS patients do not rise as would be expected and therefore, hemotocrit is not a valid measure (I personally had to overcome this presumption as my DI was worsening from episodic to florid). If severe enough, detection of a differential between urine and blood/plasma osmolality can be used to raise the index of suspicion for central DI (urine will be dilute, blood will be concentrated).

    It is important to keep in mind that very few doctors have actually recognized a case of DI and so their understanding is typically based on nothing more than the classic florid presentation provided in medical texts. Testing can be complicated and misleading if done improperly. Lastly, doctors are typically not taught that episodic DI is a problem needing treatment - or that it even exists (just drink more fluids). In support of your comment, when DI is severe enough, it is nearly impossible to adequately compensate by simply increasing fluid intake.

    Unfortunately, it appears that a rich resource of information on DI is not presently available on the web - www.diabetesinsipidus.org/. Hopefully the site is just down for maintenance but a lack of results in a Google search lead me to suspect otherwise.

    Best,

    Shane
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  13. ahimsa

    ahimsa Senior Member

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    I finally read a few web sites about diabetes insipidus (after seeing the term on these forums for a while....). On one of those sites I found this statement:
    Hmm. I happen to know that I have an enlarged bladder. In the notes from my last surgery (for removal of endometriosis tissue) there was a comment that my bladder was very large. In fact, they used the word "very" two or three times. It was almost humorous. I just figured, okay, I guess was born with an over-sized bladder.

    When I first got sick I used to get up several times a night to urinate. After I started treating the NMH (lots of extra water, salt tablets, fludrocortisone and potassium--the midodrine was not added until later) I stopped getting up at night for this reason. I found it interesting that even though I was taking in more water (3 liters a day) I was going to the bathroom less often. I don't know if my 24 hour urine volume was changed that much. It's hard to tell without measuring.

    Anyway, just a bit of rambling. I do wonder, however, what other things might cause an enlarged bladder? Is this proof that I have at least some mild DI or could it be from something else? I'll try to search on my own, of course, but would love to have input from others.
  14. CBS

    CBS Senior Member

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    FWIW, I don't know that an enlarged bladder is necessarily specific for DI. However, my personal experience was that an enlarge bladder was definitely part of the equation. When I was finally diagnosed with DI the doc ordered an ultrasound of my bladder. The tech literally could not identify it (didn't I mention earlier that diagnosing DI can be a challenge for the uninitiated?). It turned out that my bladder had enlarged to the extent that the area where she was looking did not contain the borders of the bladder (think about trying to see the outline of an elephant from two feet away). A normal adult bladder is roughly the size of a large grapefruit (max. 12-16 oz. of fluid).
  15. KC Jones

    KC Jones

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  16. Questus

    Questus Senior Member

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    This is the machine used to test for blood volume. There are not that many in the country. Here's a link to Daxor, THE company that makes the machine that accurately measures blood volume. In this link you'll find the list of hospitals in the cities that have this machine.

    When I say it's THE machine...It's the one used both at Vanderbilt and Mayo.

    (You can look at their client list.)

    http://www.daxor.com/default.aspx

    Best,
    Questus
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