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Lab: Blood Pressure and Pulse Determinations
PART 1: Pulse
Objective: Define pulse and accurately determine a subject’s radial and apical pulse. The term pulse refers to the
alternating surges of pressure in an artery that occur with each beat of the left ventricle. Normally, the pulse rate equals
the heart rate and the pulse averages 70 to 76 beats per minute in the resting state.
Background Information: Palpating Superficial Pulse Points:
The pulse may be felt on any artery close to the body surface when the artery is compressed over a bone or firm tissue.
The following is a list of pulse points commonly used:
Pulse Point:
Location:
Common carotid artery
At the side of the neck
Temporal artery
Anterior to the ear, in the
temple region
Facial artery
Clench teeth and palpitate
the pulse just anterior to
the masseter muscle
Brachial artery
In the elbow region
Radial artery
At the lateral aspect of the
wrist, just below the thumb
Popliteal artery
At the back of the knee
Pedal artery
On the top of your foot
Procedure:
1. Write a hypothesis of your pulse rate in relation to exercise. Use the If, then format. (____/1)
2. Palpate the following pulse or pressure points on your partner by placing the fingertips of the first two or three
fingers of one hand over the artery.
Note: It helps to compress the artery firmly as you begin your palpitations and then immediately
ease up on the pressure slightly.
3. Take a resting pulse rate for a minute for each partner and record it in the data table.
Lab Partner 1:
Lab Partner 2:
Carotid
Temporal
Brachial
Facial
4. Plot your values on a graph. The x-axis
should be the location of the pulse and
the y-axis should be the pulse rate per
minute. Be sure to label your axis and
title your graph.
Radial
Popliteal
Pedal
5. Which pulse point was your
strongest (greatest amplitude)?
6. Which pulse point was your
weakest (least amplitude)?
7. Can you offer any explanation of this?
8. Because of its easy accessibility, the pulse most often taken is on the carotid artery. With your partner sitting
quietly, practice counting the carotid pulse for one minute. Make three counts and determine the average.
Count 1:
Count 2:
Count 3:
Average:
9. Now you will take your carotid pulse after exercise. Do the following exercises to determine how your pulse
rates change: jogging in place for one minute, doing 15 push-ups, lying down in your chair, and one minute of
jumping jacks.
10. Immediately following exercise, take your radial pulse for one minute. Record it in the data table.
Lab Partner 1:
Lab Partner 2:
Jogging
15 Push-ups
Laying in your chair
Jumping Jacks
11. How did your pulse rate differ after exercise from that of your resting pulse rate?
12. The average pulse rate of an athlete is lower than the normal average pulse rate. Explain why this is so.
13. Why do you think the pulse is taken from arteries of the body and not veins?
PART 2: Blood Pressure
Introduction: (read very carefully to understand)
Blood pressure is the force exerted by blood against the walls of arteries and veins. It is created by the pumping action
of the heart. Blood pressure is measured in millimeters of mercury (mm Hg) and is expressed by two
Numbers—120/80, for example. The higher number is systolic blood pressure, the maximum pressure that occurs
when the heart contracts. The lower number is diastolic blood pressure, the pressure when the heart is relaxed
between contractions.
The cardiac cycle includes events in one complete heartbeat, during which both atria and ventricles contract and then
relax, and a predictable sequence of changes in blood volume and pressure occur in the heart. Pressure changes in the
right side are less dramatic but the same relationships apply.
Let’s start our discussion of the cardiac cycle with the heart in complete relaxation (diastolic). Pressure in the heart is
very low and the blood is flowing passively from the pulmonary vein and vena cava, then into the atria and through the
ventricle. The semilunar valves (also called the pulmonic and aortic valves) are closed and the AV valves (also called the
tricuspid and mitral valves) are open. Then atrial contraction occurs and atrial pressure increases, forcing blood
remaining in the atrium into the ventricles.
Then ventricular systole begins and pressure in the ventricles rapidly increases, closing the AV valves. When pressure in
the ventricles exceeds that of the arteries leaving the heart (aorta and pulmonary artery) the semilunar valves open. The
blood in the ventricles gushes through the valves and leaves the heart. During this phase, the pressure in the aorta
reaches approximately 120 mm Hg. While the ventricles are contracting, the atria are relaxing and refilling with blood. At
the end of the ventricles contracting (systole), the ventricles relax and semilunar valves close, preventing backflow.
When intraventricular pressure is less than atrial pressure, the AV valves are open and then ventricles refill again. Atrial
and aortic pressures decrease, the ventricles refill, completing a cycle. The average heart beats approximately 72 to 75
beats per minute and so the length of the cardiac cycle is about 0.8 seconds.
Equipment:
 Sphygmomanometer (A sphygmomanometer consists of an inflatable bag inside a covering called a cuff,
an inflating bulb, a manometer from which blood pressure can be read, and a valve that is used for deflation.)
 Stethoscope
 Chair
 Table or other surface to support arm
Preparation:
For the person being tested: Wear clothing that allows your upper arm to be bare. Avoid heavy exercise or eating
prior to the test.
Introduction:
The sphygmomanometer, commonly called the blood pressure cuff, is an instrument used to measure blood pressure by
the auscuiatory method. This method consists of an inflatable cuff with an attached pressure gauge. The cuff is wrapped
around the arm just above the elbow and inflated until the cuff pressure exceeds systolic pressure to stop blood flow to
the arm. As cuff pressure is gradually released, the examiner listens with a stethoscope over the brachial artery for
characteristic sounds, which indicates a resumption of blood flow into the forearm. The pressure at which the first soft
tapping sounds are heard is recorded as the systolic pressure. As the pressure is reduced, blood flow becomes more
turbulent and sounds become louder. Below the diastolic pressure, when the artery is no longer compressed, blood
flows freely and can no longer be heard. The pressure at which the sound disappears is recorded as the diastolic
pressure.
Blood Pressure =
Systolic Pressure (higher number)
Diastolic Pressure (lower number)
Procedure:
1. The subject should sit comfortably, with the arm slightly flexed, palm up, and the forearm supported at
heart level on a table or other smooth surface. If such a surface isn’t available, you will need to support the subject’s
forearm while you take the measurements.
2. Place the deflated cuff on the subject’s upper arm, with the lower edge of the cuff about 1 inch above the inner
elbow crease. The inflatable bag should rest on the brachial artery, which is on the inner part of the upper arm. The
cuff should be marked with an arrow as to where it should be touching the brachial artery. The inflatable bag should
encircle at least 80% of the arm; if it does not, use a large sphygmomanometer.
Note: The cuff should not be kept inflated for more than 1 minute. If you have trouble finding a reading within
this time, deflate, wait one minute, and try again. (A prolonged interruption in blood flow can cause fainting)
3. Apply the stethoscope lightly to the arm, just at the inner elbow crease. Make sure the stethoscope doesn’t touch
the cuff or any of the tubing from the sphygmomanometer. Many of your kits have them already built-in.
4. Place the cleaned stethoscope in your ears. While watching the manometer and listening for pulse sounds through
the stethoscope, inflate the cuff to 160 mm Hg above the point at which pulse sounds disappear. (Inflating the bag
closes off the blood flow in the brachial artery, causing the pulse sounds to stop.)
5. Slowly deflate the cuff at a rate of 3 mm Hg per second. Watch the pressure gauge and listen for a faint heartbeat.
6. When you hear the first sound, make note of the time but continue watching the gauge. This is your systolic
pressure.
7. Keep releasing the gauge until the sound disappears. When you no longer hear a heartbeat, record the number. This
is your diastolic pressure.
8. Wait 1–2 minutes and then repeat the test. Record both results and indicate which arm was used for the
measurements. For more accurate results, readings should be taken by several different people or on several
different occasions.
Remember:
• Systolic pressure is the point at which pulse sounds first become audible. You should hear faint but
clear tapping sounds.
• Diastolic pressure is the point at which the pulse sounds disappear.
(Note: If you are measuring blood pressure as part of an exercise test, the method for determining diastolic
pressure is somewhat different. Sometimes during exercise the sounds are audible all the way down to
0 mm Hg. If this occurs, diastolic pressure is the point at which there is a definite change in the loudness of
the sound—an abrupt muffling.)
Type of Pressure
Systolic Pressure
Person 1
Diastolic Pressure
Systolic Pressure
Person 2
Diastolic Pressure
Left Arm (trail 1)
Right Arm (Trail 2)
Averages
Blood Pressure Classification:
Average the results of the two sets of measurements. Refer to the table below for the rating.
Person 1: Average pressure: ___________ / __________ Classification: ____________________
(Systolic) (Diastolic)
Person 2: Average pressure: ___________ / __________ Classification: ____________________
(Systolic) (Diastolic)
Categories: Systolic (mm Hg) and Diastolic (mm Hg)
Normal:
Below 120 and Below 80
Prehypertension:
120–139 or 80–89
Hypertension:
Stage 1 140–159 or 90–99
Stage 2 160 and above or 100 and above
Analysis:
1. What was the most difficult part of measuring your blood pressure?
2. Identify one possible source of error.
3. What is considered one cardiac cycle?
4. Summarize the diastolic phase of the cardiac cycle
5. What events happen in the systolic phase of the cardiac cycle?
6. About how long is the cardiac cycle?
7. What exactly is the blood pressure cuff measuring?