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Slightly OT - BP measuring equipment ... ?

Discussion in 'Electronic Repair' started by Arfa Daily, Apr 16, 2009.

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  1. Arfa Daily

    Arfa Daily Guest

    Anyone on here had any experience of repairs to blood pressure measuring
    equipment, to the point of understanding properly the principles involved ?

  2. Charles

    Charles Guest

    Not the kind of thing one should repair, unless its a personal project.
    Even then, I think it's a bad idea.
  3. Arfa Daily

    Arfa Daily Guest

    OK, here's the story then. Not a repair as such, hence the "slightly OT" in
    the subject.

    The unit is actually mine. It's a fully automatic job, made by Nissei, who
    are quite respected in the field, I believe. It has a wrist-sized velcro
    secured air cuff, connected to the main unit by a single small bore air
    hose. No electrical connections between the two. When you hit the "start"
    button, the cuff inflates to a preset (selectable for four values) pressure,
    which is shown on the LCD as a genuinely 'measured' - i.e. not just a figure
    put there by the CPU - mmhg value. The machine then starts a controlled
    deflation of the cuff, picking up pulse soon after this starts. It appears
    to be assessing blood stopped / blood flowing by measuring the minute
    changes in air pressure in the connecting tube, caused by the vein pulsing
    under the cuff.

    Now, I've recently been sucked into the 'high blood pressure' thing by my
    doctor's surgery, and they are determined to treat me for it. Fair enough.
    However, my 'clinical care expert' - actually a feisty practice nurse with
    the disposition of a bear with a thorn in its paw - will not accept that a
    blood pressure monitor that does its measuring from the wrist, has any
    validity at all. I would like to be able to monitor my own pressure on a
    compatible basis with her, because I feel that I am a rather good example of
    elevated pressure due to white coat syndrome. This is a factor that she
    seems to ignore as being a contributory element to any readings. I don't
    dispute that my blood pressure is higher than ideal, I just don't think that
    it is as high (on average) as she insists it is, and I don't want to be
    over-medicated for the condition.

    So, onto the real question. My monitor is just about identical to the one
    she is using in the surgery. Same measurement sequence, same sound from the
    compressor, similar sized unit, similar length of time to inflate and
    deflate etc. The only difference is that mine has a plug-in wrist cuff, and
    hers has a plug-in arm cuff. She actually changed to a larger sized cuff to
    fit my arm when I was in there a couple of weeks ago, which is what led me
    to my next thought. Arm cuffs, on their own, are available from a pharmacy
    chain store down the road. They're not cheap, but nothing like as expensive
    as a whole new machine. Given that it seems to work by measuring the
    pressure pumped into the cuff to reach a primary inflation point to work
    down from, and then apparently does the 'business' measurements by looking
    at the pressure variations caused by the vein inside the cuff pulsing, can
    anyone see why my monitor should not work just the same with an arm cuff
    plugged in, instead of a wrist cuff ? I don't really want to just shell out
    on an arm cuff in the fond hope that it *will* work, and then find out that
    it doesn't, but then neither do I want to spend even more money on a
    replacement unit, if I don't have to.

    Any opinions / insights / genuine knowledge anyone ? :)

  4. Arfa Daily

    Arfa Daily Guest

    Yes, I suppose I could as long as they don't mind taking a cuff out of the
    box, and allowing me to hook it up to my machine. Perhaps I should go in and
    have a chat with the pharmacist, or see if they will do a refund if I buy
    one to try, and it doesn't work.

  5. JeffM

    JeffM Guest

    I think your assessment has validity.
    I feel quite sure *technique* is the issue.
  6. Baron

    Baron Guest

    Arfa Daily Inscribed thus:
    Good Morning Arfa,

    I've had exactly the same issues with my Doctor and practice nurse which
    resulted in me buying one on the advice of my Doctor. I bought the one
    recommended at £10 from Lloyds Pharmacy.

    The advice given was that everyone has high blood pressure at some time.
    However elevated blood pressure for an extended period (more than a few
    days) should be investigated.

    For years I have had a lower blood pressure than normal ! All the fuss
    came about because the practice nurse decided that my blood pressure
    was abnormally high and insisted that I see the Doctor.

    I rather got the impression that the Doctor didn't want to get into a
    conflict with the nurse and actually disagree with her !

    As to whether arm or wrist cuffs are better, mine is an arm cuff and is
    actually the same instrument that the practice nurse uses.

  7. Geo

    Geo Guest

    Can't help with the wrist vs arm question. A spare cuff (3 sizes) is £2.99 from
    LLoyds pharmacy (Product Code: 8212482) or a complete unit with cuff for £12.99.
    As far as the working of the beast - AFAIK it is done by fuzzy logic. The sound
    of the blood flow changes very slightly at the low pressure point and this is
    what the doctor/nurse is trained to pick up. I personally think that it is a
    subjective thing and subject to variation - but the Doc who does my annual
    medical argues forcefully against that view.
  8. GregS

    GregS Guest

    I tried a wrist monitor and could not get reliable readings. Are yours consistant?
    I read some just don't have good readings on the wrist. I use the old fashion type, manual.

    There are natural food suppliments for HBP. There are breathing excersises for HPB.
    And there is exercise and fasting.

  9. GregS

    GregS Guest

    ANother thing, have the doctor remeasure the pressure after you have been
    settled for a while.

  10. Charlie

    Charlie Guest

    Yes, I suppose I could as long as they don't mind taking a cuff out of the
    Arfa, before expending the money, at your next visit simply take your unit
    with the wrist cuff and compare the results with what the nurse gets.

    That is what I did.

    Caveat: use the same arm and leave some time between machines to allow the
    arteries to relax back to "normal".

  11. Arfa Daily

    Arfa Daily Guest

    Hi Charlie. That's kinda where I was getting to, but I have now discovered
    that Lloyds Pharmacy chain do a range of 'own brand' fully automatic BP
    monitors at a very good price. They come ex the cuff, which is then
    available in three different sizes for next to nothing, so I think my next
    move is going to be to buy just a cuff and try it on my monitor. If I get
    'sensible-looking' ball park figures, then I will take it along to the
    surgery next time, and check it against theirs. If it doesn't seem to give
    realistic figures, then I'll just finish the job off, and buy the own-brand
    monitor unit, to go with the cuff already bought. Bingo ! The job's a
    good'un, as they say ... d;~}

  12. Arfa Daily

    Arfa Daily Guest

    Some interesting stuff there Jeff. I guess the deeper in the vein is, the
    more soft tissue (muscle?) there is between the cuff and the vein. I guess
    that would have to make the cuff inflate to a higher pressure before the
    'spring' had been taken out of the intervening tissue, and pure squeeze was
    being placed on the actual vein. In a case like this, I can see how doing it
    manually by listening for a pulse, might yield a better result. What you had
    inside your one sounds pretty much identical to what's inside mine. See my
    new follow up post "BP measuring equipment - Part 2" and a couple of the
    interesting replies that have been posted in that thread, one in particular
    with some links to other material on the measurement principle.

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