®
Wireless Blood Pressure Sensor
PS-3218
4
013-15878A
Blood pressure consists of two
measurements: systolic and
diastolic pressure. It is
represented as a ratio of systolic
pressure to diastolic pressure, for
example 130/80 (“one-thirty over
eighty”).
In most parts of the world, blood
pressure is reported in
millimeters of mercury (mmHg).
Systolic pressure is the pressure
of the blood on the artery walls
when it leaves the ventricles at
peak ventricular contraction,
when the heart is emptying its
chambers of blood. It is the “top
number” of the blood pressure
ratio. Normal systolic pressure for
a male is approximately 120
mmHg and for a female is
approximately 110 mmHg.
Diastolic pressure is the pressure
of the blood on the artery walls
when the ventricles relax and the heart's chambers fill with
blood. It is the “bottom number” of the blood pressure ratio.
Normal diastolic pressure for a male is approximately 80
mmHg and for females is approximately 70 mmHg.
Systolic and diastolic pressures are affected by various
biological and environmental factors. For example, the salt
in a person's diet can cause the kidneys to change the
amount of fluid in our blood, resulting in changes in blood
pressure. Diet, stress, exercise, body position, drugs,
hormonal changes and genetic factors can affect a
person's blood pressure.
About the Sensor
The Wireless Blood Pressure Sensor consists of a
pressure sensor box and a blood pressure cuff with bulb
and valve. The sensor is a digital sphygmomanometer that
uses an electronic pressure sensor to measure the mean
arterial pressure and then calculates systolic and diastolic
blood pressure and heart rate (in beats per minute).
The blood pressure cuff consists of an inflatable bladder
connected by one hose to a hand pump bulb with a
push-button release valve, and by a second hose with a
connector that attaches to the pressure sensor box.
The Wireless Blood Pressure Sensor uses the oscillometric
technique to estimate blood pressure. When the
oscillations of pressure in a blood pressure cuff are
recorded during gradual deflation, the point of maximal
oscillation corresponds to the mean intra-arterial pressure.
The oscillations begin at approximately systolic pressure
and continue below diastolic, so that systolic and diastolic
pressure can only be estimated indirectly according to an
empirically derived algorithm.
Usage
Experiment ideas:
•
Determine the effects of exercise on blood pressure
and heart rate.
•
Explore the effects of body position on blood pressure
and heart rate.
•
Compare the blood pressure and heart rate of students
in the class.
Set Up the Hardware
Connecting the Sensor to the Cuff
Screw the luer connector on the end of the blood pressure
cuff tube onto the luer connector on the sensor.
Cuff and Arm Placement
First, find a partner. A student
cannot measure his or her own
blood pressure. Partner 1
should be the patient and
partner 2 should conduct the
measurement.
The patient should remove any
constrictive clothing or jewelry
that may interfere with the cuff
placement.
Locate the approximate position
of the main artery (brachial
artery) on the inside of your
upper left arm by pressing with
your fingers near the inside
edge of your biceps muscle
about five or ten centimeters
(cm) above the elbow pit.
Partner 2 should help the
patient wrap the cuff snugly around the upper left arm
Brachial
Artery
Palm
Sensor
Luer
Connector
Elbow
pit
Cuff
Figure 3: Cuff onto upper
Upper Left
Arm
Tubes
