IX -
A good means of controling high blood pressure : The self-measurement
of blood pressure
10.1
- Why using a self-measurement device?
10.2
- The self-measurement device
10.3 - The Inflation
and deflating of the cuff
10.4 - Ideal anatomical
site for the measurement of the blood pressure
10.5 - Validation of the device
10.6 - Conditions
and number of measurements
10.5
- Validation of the device
In order to guarantee
a good quality of the measurement, the self-measurement device
must be validated by independent organizations or experts in
blood pressure measurement. For the moment, there
is no regulation control concerning this type of device in Europe.
Thus, the quality of the self-measurement devices is very unequal,
and only very few are currently validated.
10.5.1- Methods of
validation
Presently, there are two methods of validation of the self-measurement device.
The British Medical Society for high blood pressure is one and the other is
the association for the development of the medical device (American association).
The principle of validation
is based on the comparison between the level of the blood pressure
obtained with the reference method, which is the mercury sphygmomanometer,
and the device being validated. The measurement
is done at same time, using a branch in Y, a pipe being directed
towards the reference device and the other one being directed towards
the device being validated. For the "Advancement of medical
instrumentation association", the difference between
the two devices has to be under 5 mm of mercury (mean of
the values).
The British Hypertension
Society has a different way to validate the self measurement
device: The device is classified with levels A to D, from best
to worth device.
| |
Absolute
difference between devices (mmHg) |
Level |
< or
equal to 5 |
< or
equal to 10 |
< or
equal to 15 |
A |
60
% |
85
% |
95
% |
B |
50
% |
75
% |
90
% |
C |
40
% |
65
% |
85
% |
D |
< C |
To obtain
a level, 3 percentages has to be upper or equal to values seen
in each square. For example, to obtain a A level a minimum
of 60% of the difference of 5 mmHg between the gold-standard
device and the self-measurement device has to be detected,
85% of the difference for 10 mmHg between the two devices and
95% of the difference of 15 mmHg.
10.5.2 - The cuff The validation of the
device also includes the validation of the cuff, whose diameter
must be well adapted to the circumference of the arm. A too small
cuff tends to raise the blood pressure whereas a too large cuff
has the opposite effect. There are three sizes of cuff: a child
size, an adult size and an obese size. 10.5.3 - Reliability
of the device with time Surprisingly, there
is not precise data relating to the lifespan and the reliability
of the self-measurement devices with time. The maintenance provided
by traders is often based on theoretical information. In fact, we advise you
to show your device regularly to your practitioner who will take
simultaneously the blood pressure with his device and yours.
According to the difference between the two techniques, your
physician is able to validate your device. 10.5.4 - The validated
self-measurement device of blood pressure The validated blood
pressure self-measurement devices are described in the following
sheet (validation of the European Society of Hypertension):
| Omron HEM-705CP |
| Omron HEM-703CP |
| Omron M4 |
| Omron MX2 |
| Omron HEM-722CP |
| Omron HEM-735CP |
| Omron HEM-713CP |
| Omron HEM-737
intellisense |
The NISSEI DS-175 and PHILIPS
HP-5332 devices are also partially validated by the British Society
of Hypertension (respective levels : D/A and C/A).
All these
devices are measuring blood pressure on the brachial site, and
two wrist devices could be recommended : The Omron R3 and RX.
| File
last modified on : 28 sep 2003 |
|
|
