How It Is Done
Specific instructions
When you first get a blood pressure monitor, take it to your
doctor's office to make sure it is working right. Have your health professional
take your blood pressure and then compare that result with your own device. Ask
your health professional to watch you use your monitor to make sure that you
are using it correctly. It is a good idea to have your monitor checked every
year.
The size of the
blood
pressure cuff
and where you place the cuff on your arm can change your
blood pressure readings. If the cuff is
too
small
or
too
large
, the measurements will not be accurate. The inflatable part of the
cuff needs to wrap around at least 80% of your arm. Hospital and medical supply
stores generally carry many cuff sizes and can help make sure that your cuff
fits you. See a picture of a
cuff with
the proper fit
.
Your blood pressure in your right arm may be higher or lower than
the blood pressure in your left arm. For this reason, try to use the same arm
for every reading. Blood pressure readings also rise and fall at different
times during the day. They are usually highest in the morning and lowest in the
evening. Ask your doctor if you should take your blood pressure at the same
time of day each time you take it, or if you should take your blood pressure at
different times of the day.
The instructions for using blood pressure monitors vary depending
upon the type of blood pressure monitor you choose. Here are some general
guidelines:
- Take your blood pressure while you feel
comfortable and relaxed. Sit quietly for at least 5 minutes with both feet on
the floor. Try not to move or talk while you are measuring your blood
pressure.
- Sit with your arm slightly bent and resting comfortably
on a table so that your upper arm is on the same level as your heart.
- Place the blood pressure cuff on the skin of your upper arm. You
may have to roll up your sleeve, remove your arm from the sleeve, or take your
shirt off.
Manual blood pressure monitors
Sit with your arm slightly bent and resting comfortably on a
table so that your upper arm is on the same level as your heart. Expose your
upper arm by rolling up your sleeve but not so tightly as to constrict blood
flow. If you are not able to roll up your sleeve, remove your arm from the
sleeve or take off your shirt. Wrap the blood pressure cuff snugly around your
upper arm so that the lower edge of the cuff is about
1 in. (2.5 cm) above the bend
of your elbow. A large artery (called the brachial artery) is located slightly
above the inside of your elbow. You can check its location by feeling for a
pulse in the artery with the fingers of your other hand.
If you are using a stethoscope, place the earpieces in your
ears and the bell of the stethoscope over the artery, just below the cuff. The
stethoscope should not rub on the cuff or your clothing, since this may cause
noises that can make your pulse hard to hear. If you are using a cuff with a
built-in stethoscope bell, be sure the part of the cuff with the stethoscope is
positioned just over the artery. The accuracy of a blood pressure recording
depends on the correct positioning of the stethoscope over the artery. You may
want to have another person who can use a stethoscope properly help you take
your blood pressure.
Close the valve on the rubber inflating bulb. Squeeze the bulb
rapidly with your opposite hand to inflate the cuff until the dial or column of
mercury reads about 30 mm Hg higher than your usual
systolic pressure. (If you don't know your usual
pressure, inflate the cuff to 210 mm Hg or until the pulse at your wrist
disappears.) The pressure in the cuff will stop all blood flow within the
artery temporarily.
Now open the pressure valve just slightly by twisting or
pressing the valve on the bulb. The pressure should fall slowly at about 2 to 3
mm Hg per second. Some blood pressure devices have a valve that automatically
controls this rate. As you watch the pressure slowly fall, note the level on
the dial at which you first start to hear a pulsing or tapping
sound through the stethoscope. The sound is caused by the blood starting
to move through the closed artery. This is your systolic blood
pressure. If you have trouble hearing the start of your pulse through
the stethoscope, you can check your systolic blood pressure by noting the level
on the dial when you are able to feel the pulse at your wrist once
again.
Continue letting the air out slowly. The sounds will become
muffled and will finally disappear. Note the pressure when the
sounds completely disappear. This is your diastolic
blood pressure. Finally, let out all the remaining air to relieve the
pressure on your arm.
Be sure to write your numbers in your log book, along with the
date and time.
Electronic blood pressure monitors
For electronic models, press the on/off button on the
electronic monitor and wait until the ready-to-measure "heart" symbol appears
next to zero in the display window. Then press the start button. The cuff will
inflate automatically to approximately 180 mm Hg (unless the monitor determines
that you require a higher value). It then begins to deflate automatically, and
the numbers on the screen will begin to drop. When the measurement is complete,
the heart symbol stops flashing and your blood pressure and pulse readings are
displayed alternately.
All blood pressure monitors
At first it is a good idea to take your blood pressure 3 times
in a row, 5 or 10 minutes apart. As you get more comfortable taking your own
blood pressure, you will only need to measure it once or twice each
time.
Check your blood pressure cuff frequently to see that the rubber
tubing, bulb, valves, and cuff are in good condition. Even a small hole or
crack in the tubing can lead to inaccurate results.
To help develop your skills, see:
Monitoring your blood pressure at
home.