How Accurate Are Home Blood Pressure Monitoring Devices?

How Accurate Are Home Blood Pressure Monitoring Devices?

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QUESTION: I am considering purchasing the equipment to measure the blood
pressure of my husband, who has a mild hypertensive condition, and have
noticed a number of different devices in the local pharmacy. How accurate are
they, and how can you be sure of getting accurate results when using a home
monitoring device?
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ANSWER: That is a fine idea, for it can help greatly in helping your husband
deal with his condition. Home blood pressure monitoring devices give
hypertensive patients an immediate idea of how well they are doing with their
medication program. They also help the patient's doctor by making creating a
record of daily readings so that he can evaluate, in an ongoing fashion, the
progress of the patient.
Three different types of instruments are currently available for home
use. All three are packaged in kits that contain a blood pressure cuff, and,
if necessary, a stethoscope.
The first of these devices, the mercury sphygmomanometer, is calibrated
by the manufacturer so that the top of the mercury column stands precisely at
zero when the cuff is deflated. This device is considered the most accurate
and reliable of the three. If the mercury column is soiled or does not rest
at zero, the instrument should be returned to the manufacturer for
recalibration.
Nonelectronic aneroid manometers cost less and are accurate if properly
calibrated. They should be calibrated once every year against a standard
mercury sphygmomanometer.
The newest choice for home blood pressure monitoring is one of the many
electronic devices that provide a digital readout and do not require a
stethoscope. Some are fully automated so that the push of a button inflates
and deflates the cuff. These are particularly useful for persons with hearing
deficiencies or those anxious about the to use of a stethoscope, or even just
for those who wish to have an instrument that is easy to use.
Moving the arm, failing batteries or incorrect placement of the cuff can
cause erratic measurement, so before an unusual result leads you to assume the
worst, be sure to test your pressure a second time. False readings may also
result from an ill-fitting cuff, so choose the right size if you are given a
choice. Also, a noisy environment may cause a high reading. Recordings more
than once or twice a month are generally unnecessary for hypertensive
patients, who should expect some normal daily fluctuations in pressure.
However it does make sense to check the pressure under the same conditions
each time, so that comparisons are valid. Pick a time of the day when stress
is at a minimum to obtain a good base line reading.
There is one additional benefit from using these devices which isn't
always written about. Just using the instrument reminds patients that they
should be taking their medication on a regular basis, even when they are
feeling fine, for that's the best way to keep those readings down!