Laboratory Exercises

 

 

Lab 1: Ausculatory vs. Oscillometric Measurement Techniques

Lab 2: Transient Blood Pressure Changes

Lab 3: Ergometer Training

Lab 4: Research Experiment

Lab 5: Mean Arterial Pressure Determination

 

References

 

 

 

Lab 1: Ausculatory vs. Oscillometric Measurement Techniques

Suggested Time: 30 minutes

 

Purpose:  To compare two methods of indirect blood pressure measurement.

 

Materials:

·        Computer

·        Sphygmomanometer

·        Stethoscope

·        DynaPulse hardware and software package

·        Paper and pencil

 

Procedure:

(You should work in groups of 4 or 5)

Part A - Auscultatory Blood Pressure Measurement

1.      The study group should be separated into sub-groups of two or three students so that each member can take the blood pressure of another student.

2.      Each subject should sit quietly for three minutes before completing a measurement

3.      Each student should take turns taking the blood pressure of another student using the sphygmomanometer and stethoscope (auscultatory method).

4.      The systolic and diastolic blood pressures should be recorded manually.

Part B - Oscillometric Blood Pressure Measurement

1.      Each group member should sit quietly for three minutes prior to completing a measurement.

2.      The oscillometric cuff should be placed on the arm of the subject and the computer program activated to take a measurement.

3.      In order to ensure an accurate measurement, the subject should relax and minimize all movement including muscle contraction during the deflation of the cuff.

4.      Following the measurement, the oscillometric systolic blood pressure (SBP) and diastolic blood pressure (DBP) should be compared to blood pressure values obtained by the auscultatory method in part A.

5.      In order to evaluate both methods for the accuracy of their mean arterial pressure (MAP), it is necessary to estimate the MAP attained using the auscultatory method by the following formula:

MAP = 1/3 SBP + 2/3 DBP

Compare the MAP calculations derived by the auscultatory systolic and diastolic pressures with the DynaPulse MAP.

 

 

 

Lab 2: Transient Blood Pressure and Hemodynamic Changes

Suggested Time: 50 minutes

 

Purpose:  To investigate the physiological changes in blood pressure and other hemodynamic parameters as a result of arm and body position, noxious stimuli, and mild exercise.

 

Materials:

·        Computer

·        DynaPulse hardware and software

·        Internet Access for DynaPulse Analysis Center (DAC)

·        Container of ice water (0-2 degrees Celsius)

 

Note: In order to capture changes in blood pressure, the range for blood pressure measurement may need to be changed. During the different parts of the lab the systolic, diastolic, or both may either increase or decrease.

 

Procedure:

(You will work in groups of 4 or 5)

Part A - Rested Blood Pressure and Hemodynamic Changes

1.      After each member has rested (sitting) quietly for three minutes, measure each group member’s blood pressure using the DynaPulse oscillometric system.  Upload the waveform data to the DynaPulse Analysis center, and retrieve the hemodynamic report for each member.

Part B - Arm Position Changes - The Gravity Effect

1.      Have one subject rest in the seated position for three minutes.

2.      Place the measurement cuff on the arm of the subject during the resting stage.

3.      Have one member of the group raise the relaxed arm of the subject above the subject’s head while another member completes a measurement. For best results make sure to hold the arm directly above the head and ensure that the subject is not contracting the muscles of the arm.

4.      Compare the subject’s base measurement from Part A with the results of Step 3.

Part C - The Cold Reflex

1.      Have a different member of the group rest in the seated position for three minutes.

2.      Have the measurement cuff placed on the arm of the subject.

3.      Place the hand of the subject in a small bucket of ice water for approximately two minutes. (Hand should be submerged to the wrist for the entire time period).

4.      After the two-minute period, remove the subject’s hand and place arm at their side.

5.      Complete another blood pressure measurement as soon as the arm is removed from the ice water.

6.      Compare the results of Part A with Step 5 for the subject.

Part D - Response to Exercise

1.      Have a different member of the group jog in place for three minutes.

2.      After three minutes, have the subject sit and immediately take a measurement.

3.      Following two minutes of recovery, complete another measurement.

4.      Compare the baseline measurement in Part A with both Steps 2 and 3.

Part E - Orthostatic changes in Blood Pressure

1.      Have one member of the group lay on a desk in a supine position for three minutes.

2.      After three minutes, take the subjects blood pressure using the DynaPulse.

3.      Have the subject sit up, swinging their legs off of the table, and take another measurement (remember to minimize movement during the measurement).

4.      Compare the results from Step 1 and 2 on your sheet.

 

 

Lab 3: Ergometer Training

Suggested time: 35 Minutes

 

Purpose:  To investigate the physiological changes in the cardiovascular system as a result of exercise.

 

Materials:

·        Cycle ergometer

·        Computer

·        DynaPulse system hardware and software

·        Internet Access for DynaPulse Analysis Center (DAC)

 

Procedure:

During an eighteen-minute exercise study we will monitor several parameters of cardiovascular function in order to achieve a better understanding of the behavior of the body under physical stress. The subject will be required to maintain a pedal rate of 80 rpm while the workload is incrementally increased according to the schedule below. In order to achieve an accurate blood pressure, hemodynamic, and heart rate readings it is essential that the subject discontinue all exercise and remain still during each measurement stage. The DynaPulse is a clinical grade oscillometric blood pressure monitor, and therefore any movement such as minimal muscle contraction or repositioning of the arm will cause the pressure signal to be distorted and skew the measurement. The arm should be held completely still at the height of the heart by a bystander and the subject should completely relax the arm. Following the measurement the subject will continue the protocol as outlined below.

Study Timetable:

TIME

RPM

FORCE

0-3 min

80

300

3-4 min

MEASURE

MEASURE

4-7 min

80

600

7-8 min

MEASURE

MEASURE

8-11 min

80

900

11-12 min

MEASURE

MEASURE

12-15 min

80

1200

15-16 min

MEASURE

MEASURE

16-17 min

RECOVERY

RECOVERY

17-18 min

MEASURE

MEASURE

During testing the following parameters should be received in the table below:

Systolic Blood Pressure (SBP): The maximum pressure in the system

Diastolic Blood Pressure (DBP): The minimum pressure in the system

Mean Arterial Pressure (MAP): Time weighted average of the SBP and DBP

Heart Rate (HR): The number of heartbeats per minute

Cardiac Output (CO): The amount of blood pumped from the heart per minute (stroke volume x heart rate)

Systemic Vascular Resistance (SVR): The body’s total resistance to blood flow

Perceived Exertion (PE): The subject's perceived work on a scale 1-10

 

Data Table:

STAGE

RPM

FORCE

PE

SBP

MAP

DBP

HR

CO

SVR

1

80

300

 

 

 

 

 

 

 

2

80

300

 

 

 

 

 

 

 

3

80

300

 

 

 

 

 

 

 

4

80

300

 

 

 

 

 

 

 

5

RECOVERY

RECOVERY

 

 

 

 

 

 

 

 

 

Lab 4: Research Experiment

Suggested Time: 50 Minutes

 

Purpose:  To study a physical phenomenon such as the influence of gender or age on the blood pressure in order to understand data acquisition, analysis, and presentation.

 

Materials:

·        Computer

·        DynaPulse hardware and software

 

Background:

Currently a great deal of medical research is focusing on factors that may affect the blood pressure. Genetics, disease, and aging process are only a few of the factors that may influence blood pressure changes. Therefore, it is critical that we develop a method to systematically evaluate observations.

Procedure:

Part A - Control Group Determination

1.      In order to properly evaluate a phenomenon it is necessary to define a control group. Determining control groups may be based on personal interpretation. In most cases, the natural or common state is defined as the "control". When studying the influence of age on blood pressure, a young group would be selected as the control group due to the fact that a higher percentage of young individuals have normal blood pressures. However, in studying the influence of gender on blood pressure, males or females may be arbitrarily selected as the control group.

Part B - Data Acquisition

1.      In order to study the influence of gender on blood pressure, separate the study group into males and females. In order to study the effects of age, separate the study group into a young and old group. It should be noted that the larger the study groups the more statistically significant the results.

2.      Designate a new group on the Student/Group directory and have each student of the female/male or young/old group complete a seated and rested blood pressure measurement.

3.      Designate a new group on the Student/Group directory and repeat step 2 for the other group. Once again, make sure to save all measurements.

Part C - Data Analysis and Presentation

1.      In order to statistically analyze and graphically display the results for each group, use the Edit feature to “mask” any bad measurements that may be the result of measurement artifact and should not affect the study results.

2.      The minimum, maximum, mean, and standard deviation for the systolic, diastolic, mean arterial pressure, and heart rate can be calculated using the Analysis feature. The normal distribution curves will be plotted for each parameter as well.

3.      The final results for each group should be presented as the mean +/- the standard deviation for each parameter. For example the systolic blood pressure may be presented as “127 +/- 4 mmHg”.

 

 

Lab 5: Mean Arterial Pressure Determination

Suggested Time: 30 minutes

 

Purpose: To compare the DynaPulse mean arterial pressure measurement with a simple approximation of the mean arterial pressure based on the systolic and diastolic pressures.

 

Materials:

·        Computer

·        DynaPulse hardware and software

 

Background:

The DynaPulse system is a clinical-grade blood pressure device that actually measures the mean arterial pressure extremely accurately. Traditional auscultatory blood pressure devices do not measure the mean arterial pressure and therefore must approximate the value. A simple formula was developed in which:

MAP = 1/3 SBP + 2/3 DBP

However, the formula above is only an approximation.

Procedure:

1.      Select a group of individuals in which to compare the mean arterial pressure measurement with the simple approximation.

2.      Each member should complete a seated and rested blood pressure measurement with the DynaPulse system. Make sure to save each measurement.

3.      Complete the table below to compare the two techniques.

STAGE

SBP

DBP

MAP APPROX

MAP MEASURED

DIFFERENCE

%DIFFERENCE

 

 

 

 

 

 

 

DIFFERENCE = MAPMEASURED - MAPAPPROX

%DIFFERENCE = MAPMEASURED - MAPAPPROX/ MAPMEASURED

4.      After completing the table, calculate the average value for each column by dividing the total by the number of subjects.

 

 

___________________________________________________________

 

References

 

1.      Cardiovascular Disorders. Springhouse: Springhouse, 1984.

 

2.      Cardiovascular Physiology. New York: Oxford University Press, 1990.

 

3.      Sixth Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI). U.S. National Institute of Health, National Heart, Lung, and Blood Institute (NIH Pub. No. 98-4080), November 1997.

 

4.      Fishmen, AP ed. Circulation of the Blood - Men and Ideas. Bethesda, MD: American Physiological Society, 1982.

 

5.      Guyton, AC. Textbook of Medical Physiology. 8th ed. Philadelphia: W.B. Saunders, 1991.

 

6.      Human Physiology - Foundation and Frontiers. St. Louis: Times Mirror/Moshy College Publishing, 1990.

 

7.      Physicians Reference I. Pulse Metric, Inc. 1992.