V - How
to measure high blood pressure?
Principles
5.1 - The
most reliable method: to place a probe measuring the pressure directly
in the artery
5.2 - The most
useful method: The measure of the blood pressure using a sphygmomanometer
with a cuff
Measurement
of the blood pressure
5.3 - At rest
at the doctors
5.4 - At rest
at home, using a self-measurement device
5.5 - During
a physical exercise
5.6 - Measurement by an ambulatory monitoring of
the blood pressure during 24 hours
Description of the device
5.7 - The cuff
5.8 - Method
for the measurement of the blood pressure
5.9 - The sphygmomanometer
5.6 -
Measurement by an ambulatory monitoring of the blood pressure during
24 hours
The blood pressure can be measured during 24 hours using an automatic device.
In general, this device measures the blood pressure every 15 minutes during
the day and every 30 minutes during the night, these intervals can also be
defined differently.
In order to obtain a good
quality of the measurements, it is essential to undertake this examination
in good conditions: this examination must be carried out on an active
person, apart from a stop for work or during the weekend. In order
to correlate the blood pressure peaks and troughs, a daily-report
of activity must be delivered by the physician and be filled out
by the patient.
Moreover, the physician
or the technician who installs the device must explain clearly to
his patient that it is possible at any time to start a measurement
of the blood pressure by pressing on a button reserved for this use.
Ambulatory monitoring of
the blood pressure, at home, during 24 hours
Use of the automatic device of measurement
of the blood pressure during 24 hours
This measurement is used
in several cases:
- If a patient has
a doubtful high blood pressure during the consultation in the
physician office, and the physician wants to know the real
blood pressure level and needs to eliminate a “white coat” hypertension;
- If a patient is already
treated for an arterial hypertension and the physician wants to
evaluate the effectiveness of the treatment over 24 hours;
- If a treated patient
feels faint, and then the recording of the blood pressure over
24 hours is looking for an arterial hypotension.
On
the other hand, this examination is of no interest when the high
blood pressure is obvious.
The results
appear as shown below, in the form of tables, diagrams, and day and
night averages.
A high blood pressure is
defined by a blood pressure level up to 135/85 millimetres of mercury
(13,5/8,5) for the period of day and 125/75 millimetres of mercury
(12,5/7,5) for the period of night.
Day-night variation of
the blood pressure is also very important to consider. In physiological
conditions, the blood pressure is lower during the period of night
compared to the period of day, and this variation must be equal to
at least 10%. But sometimes, this cycle is not respected, which testifies
to the severity of the high blood pressure or the existence of a
disease responsible for a high blood pressure (secondary high blood
pressure).
Many studies have shown
the benefit of this blood pressure measurement to predict the occurrence
of cardiovascular events: the blood pressure measured over 24 hours
by an automatic device seems to be a better index of the cardiovascular
risk than the blood pressure measured in the physician’s office.
Risk
of cardiovascular events in patients having an average systolic
blood pressure with 180, 160 or 140 mmHg with the ABP (Ambulatory
Blood Pressure) according to time.
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last modified on : 28 sep 2003 |
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