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 ?
Arfa