From a member, Ken Rudd - blood pressures and test equipment.

- Yes, maybe readers may want to first revel in my old age? - so here it comes
- nearer to my 86th year than to any other.........!
- and when I started to take this blood pressure subject seriously, I was only
70, and my pressure was suggested then as marvellous "for my age" (!) by the
super medic Dr. Sam Baxus (wait for it - as it is now outdated ) then a reading
of 135 /75..pulse 70 something..

Now that figure is,I see, listed medically as around a top acceptable pressure
by the front line medics ( no, not the others who have not yet read the news!
They will still accept 145 as ok!)

Before then, and since, I have for many years used many, many biochemical
pressure improvers ....Growth Hormones injected for the last 16 years ..... but
if you want me to say which one worked and which did n't, please call my twin
brother who did not take any of the same pills.
........ but as he has been dead for years.......

But at a guess, my regretted slow start on Algerberium, (ALT 711) as was badly
interrupted - but now back on line and ramped slowly to 200 mg per. day over 6
months mixed in pure Lemon Juice for store, is likely mainly responsible for my
morning wake up resting pressure of now 110/60 with a Resting Pulse of 55.
I love it.
During the normal commercial working day ( Yes, say 40 to 60 hrs a week) I now
expect a read out of 120/60 and a pulse 60 to 65 - if the last cigarette was a
few minutes away......or my rowing machine read out shows I have just covered 1
mile in 6 minutes in a simulated big rowing boat.....as that sort of thing tends
to put it up a bit.

Well maybe the story of my blood pressure readings can add a flavour to this
particular account so here goes.......It is one only prompted by the 'Kitty'
insert which reads :-
" in the old days of manual blood pressure measurement..............."
which I supposed means the now current use of digital kits?.....and that one is
being used now for these read outs?
If so, please read on, if not - how about locating the delete button?

My Son Dr.S.Rudd visited an international medics equipment show in UK. and
arrived on the display stand of a famous European medical equipment wholesaler -
wearing his innocent enquirer face when he deliberately asked for a blood
pressure test from the ever attentive salesman,willingly given from one of his
many displayed digital machines
.
.....and one who quickly taught him (!) how to use a digital blood pressure test
machine of top quality.......even offering a trade discount ....and seeking
repeat orders.........

The 5 readings were recorded, averaged and stored, in highly efficient manner
and the Steve read out was seen with a smile & he innocently asked if he could
now try 'that other one .....over there' and again the same energetic action
took place.
.
.....but with medically significant different readings, neither having a direct
relationship to each other, nor to Steve's own accurate readings (about the same
as mine - he is 44) which is what Steve had expected.
The salesman was non - plussed - and switched back to the first kit and checked
batteries........tested again - still got no consistency, nor even the same
readings either ................So when Steve suggested 'try yet another?' a
third digital was willingly brought into play...........also batteries checked
etc,

.....and yet another set of different readings appeared which were significantly
different from both those obtained on the other two ...and these also were
unacceptable...to Steve.
Steve recommended the salesman to examine his medical liabilities and
left..........

I have three digital blood pressure machines, all of high quality, one a wrist
type, the other two, a wrap around the upper arm type.........(I need them as I
live in three countries)

My first alert of obvious problems was when my pressure read out during a midday
rush about - my normally recorded pressures were visually replaced now by
screaming high 180/ 90 - taken because I had felt I was not too well that
day.........so now I panicked.....heart attack ........denied by my steady pulse
ticking way at 65 despite the stress............ .

Dr. Lopez arrived to bury me at about an hour later (!) but he took my blood
pressure first, with his ancient design hand pump -and recorded 120/ 65 with 60
pulse while I laid there waiting for my heart attack -
Oh yes, - hindsight please step in now.......

.'but you had rested for an hour by then?.of course it's was now lower '......
You bet I did..I was truly frightened!

So, How about going 'Back to mine?' but of course, good idea thanks - reads =
180/ 90!

Steve Rudd has, since his Exhibition visit checked further on this subject and
has concluded that as digital test systems are thus illustrated as unreliable,
he has discarded that risk and uses only the old type on patients.
His detected common failure point of those tested, he says, may lay in the
microphone of varying quality and always seen as depreciating efficiency over a
year or more.

He has carried out 180 + readings on each of three new digital machines he had
in stock and compared them with the hand type, finding that the average new
digital machine lasts with medical accuracy for about 100 tests, before
beginning to slowly deteriorate.....
By 180 tests - readings are becoming variable and so far out as to be seen as
not within medical parameters.
That is why he went on the exhibition stand of his suppliers in the first place,
to prove the point..
I have tested sets of quality alkaline batteries fresh out the packet and
obtained voltage readings varying from 1.3v to 1.6v. (I used a lot of batteries
on another unrelated use - now have rechargeable - not tested again for this
ceased application.

Suppose they all happen to be 1.3V?
Try it......yes, it does seem to effect my readings, so maybe yours too?
But now I do not use a digital electric machine!`
Thanks for your time...........Ken

[Thanks, Ken, for both the information and the good laugh. You definitely have a
way with descriptions. I can almost hear your British accent too telling the
tales.... To others, we've been in email correspondence with Ken for over 2
years so therefore his high activity level and witty humor at age 86 is not new
to us ;>)

Seriously though, I'd not heard that the digital blood pressure meters could
degrade over time.

Ken, you don't mention when (how long ago) your son Steven had his experience
with digital blood pressure measuring equipment at the medical equipment show in
the UK. I wonder about this because of the conclusions I found in the few papers
(through searches at PubMed and Scirus) regarding inaccuracy or unreliability of
home or clinic digital equipment. PMID: 7934182: "Ensuring the accuracy of
digital sphygmomanometers for home use." - describes a technique for assessing
the accuracy of digital equipment compared to the standard mercury for both
manual and automatic inflation mechanisms. (1994) Since that publication date,
there have been several papers providing some comparison of specific arm located
digital equipment (usually by brand name) vs mercury (and sometimes also
specific wrist or finger devices) on a test sample population. The conclusions I
saw in almost all the abstracts I perused are that the arm (brachial artery)
digital BP equipment measures sufficiently close to the mercury equipment to be
used. (for example: PMID 11485126, PMID: 12488652, PMID: 15021079) These
conclusions of acceptability are for the arm cuff devices intended for
measurement during inactivity; variations are noted in some papers comparing
ambulatory measurement of blood pressure.

To be noted, the topic of a few papers are what is termed "community-based
automated blood pressure measuring devices" which are described as often
inaccurate. [PMID: 7742964, PMID: 12000246] These are the large machines seen in
pharmacies and grocery stores - though I haven't seen any recently. Maybe the
problems with inaccuracy resulted in their removal.

A number of papers have addressed inaccuracy of aneroid (dial type)
sphygmomanometers in comparison to the mercury (considered by many to still to
be the standard) and also digital versions. (PMID: 12488650, PMID: 16050862,
PMID: 16077263) From the latter which addressed aneroid, mercury and automated
(digital), "Accuracy of the pressure scale of sphygmomanometers in clinical use
within primary care.":
"RESULTS: The key finding of this study is that 17.9% (50 out of 279) of all
surveyed devices gave errors exceeding the +/-3 mmHg threshold. Of these, 53.2%
(33 out of 62) of aneroid devices were found to be reading in error by more than
+/-3 mmHg compared with 7.8% (16 out of 217) of the combined population of
mercury and automated devices. The difference between these groups is
statistically significant (P=0.002). Significant differences in the performance
of specific models of aneroid, mercury and automated devices were also
identified."

[As I understand it, this paper is only dealing with the pressure measurement
meter itself and not the method of measuring the exact systolic and diastolic
point as the pressure in a cuff is slowly released. It is in that respect only
that +/-3 mmHg would be relatively large, since it would not be very significant
with respect to the overall measurement of systolic and diastolic. I think the
difference between a mercury and dial type is a little like the difference
between a balance and a spring scale. The second must be calibrated and such
calibration can change with time and environmental conditions. --Paul]

From the papers I read, it would appear that generally differences between a
mercury sphygmomanometer and a digital variety are insignificant. However,
individual machines can and have been seen to be inaccurate or become
unreliable. If Steve is aware of any published studies showing inaccuracies in
digital sphygmomenometers - or even letters to journal editors by health care
practitioners - I'd be interested in seeing a copy or getting Internet links to
them.

If I obtained an unusually high or low reading with my usual equipment - and I
or the person on whom I was using it appeared (and felt) physically well - I
would first remove the cuff and make sure it was reapplied properly, even on the
other arm. If the strange measurement was repeated on me or the same person, I
would test it on someone else whose BP I know from previous measurements. If the
unusual measurement persists, then I would conclude that the sphygmomanometer is
most likely faulty. **Kitty]