Hands-on Activity What's with All the Pressure?

Learning Objectives

After this activity, students should be able to:

• Describe the tools used to measure blood pressure.
• Measure a person's blood pressure using appropriate equipment.
• Describe how blood pressure is measured with a sphygmomanometer, which gives a reading of systolic over diastolic pressure in units of mmHG-millimeters of mercury.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

Each group needs:

• blood pressure cuff
• stethoscope
• Measuring Blood Pressure Worksheet, one per student

Note: Check to see if a local hospital or clinic will loan your class enough blood pressure cuffs and stethoscopes.

Worksheets and Attachments

Pre-Req Knowledge

It benefits students to already know how blood flows through the heart, as covered in Lesson 1 of this unit, Heart to Heart ).

Introduction/Motivation

Believe it or not, the heart incurs very large amounts of strain over the course of a person's life. Elevated levels of pressure can put a person at risk of various heart conditions that can be life threatening. One way to monitor the pressure exerted on the arteries leading away from the heart is to measure blood pressure.

What factors might affect a person's blood pressure? (Possible answers: stress, smoking, drinking alcohol or caffeinated beverages, diet, exercise.) To take good care of our hearts, it is important to be aware of our blood pressures. Today we will learn how to measure blood pressure and practice doing so – just like a medical practitioner does! As you participate in today's activity, think about the Challenge Question presented in Lesson 1 and how it is related to what we are learning in today's activity.

Procedure

Background

This activity is meant to give students hands-on experience with taking blood pressure readings, as well as motivate them for Lesson 2, Blood Pressure Basics, in which they learn more about blood pressure and its relationship with the heart and the cardiovascular system. While most of the information about blood pressure will be saved for the upcoming lesson, provide students with the following information:

Blood pressure can be measured using two tools, a stethoscope and a sphygmomanometer. A sphygmomanometer, also known as a blood pressure cuff, has a dial to measure the pressure in the cuff. The stethoscope is used to listen to the heart rate and pulse. Blood pressure is measured as one number over another number. The first number, or numerator, is the systolic pressure. The second number or denominator is the diastolic pressure. If a patient's systolic pressure is 120 and the diastolic pressure is 80, the blood pressure reading is "120 over 80."

The above information is sufficient for this activity. Encourage students to write down any other questions that arise, as motivation for the upcoming lesson.

While explaining the information above, pass around a blood pressure cuff and a stethoscope for all students to see. Then conduct a demonstration of taking blood pressure on a student volunteer following the steps below.

Before the Activity

• Make copies of the Measuring Blood Pressure Worksheet, one for each student.

With the Students

1. Hand out the worksheets.
2. Ask a student to come to the front of the room. Begin the demonstration of taking a blood pressure reading by following steps #3-9.
3. Place the blood pressure cuff on the upper arm of the student. If clothing is thick, ask him/her to roll up his/her sleeve). Place the bottom of the cuff just above the elbow.
4. Place the stethoscope so that it is between the patient's skin and the blood pressure cuff. Place it just above the elbow, on the inside of the arm―on the inside crook of the arm. Mention that his positions it over the brachial artery.
5. Tighten the cuff around the student's arm and stethoscope so that is it snug, but not tight.
6. Make sure the relief valve (the screw knob attached to the bulb of the cuff) is completely closed, and press the bulb several times until the dial on the cuff reads 200.
7. While listening through the stethoscope, slowly turn the relief valve so that some air escapes at a slow but steady rate. You should not hear any pulse in the stethoscope yet, and you should note that the needle on the dial is slowly going down.
8. Continue to release air and listen until you first hear a pulse through the stethoscope. Mentally record the number the needle is on when you first hear the sound. This number is the patient's systolic pressure.
9. Continue to release air and listen, this time until the pulse sound goes completely away. The number that the needle is on when the sound stops is the patient's diastolic pressure.
10. Record both numbers on the board for the class to see. Release any residual air from the cuff, and remove it and the stethoscope from the student's arm.
11. After the demonstration, divide the class into small groups, each with a blood pressure cuff and stethoscope. Ask each student to take a blood pressure reading of the other two group members. Walk around as students work with the equipment and try to measure each other's blood pressure. Offer advice as you maneuver amongst the students.
12. Once students have finished and recorded the readings, have groups work together to brainstorm answers to the worksheet questions.

Vocabulary/Definitions

diastolic: The period when the heart is in relaxation and dilation.

sphygmomanometer: A tool used to measure blood pressure. Also called a blood pressure cuff.

stethoscope: A tool used to listen to heart rate and pulse.

systolic: The period when the heart is contracting.

Assessment

Pre-Activity Assessment

Research Comparison: Ask students to refer to the 10 heart diseases that they researched as part of the Lesson 1, Heart to Heart, and list on a separate sheet of paper any diseases they found that include information about blood pressure. Tell them to write down next to each disease they listed whether this disease was a result of high or low blood pressure or if the disease led to high or low blood pressure. Choose a few students to share information on one of their researched diseases and how it relates to blood pressure. This assessment activity helps students make a connection between this blood pressure measurement activity and the Challenge Question presented in Lesson 1.

Activity Embedded Assessment

Measuring Blood Pressure: While students take each other's blood pressure, circulate the classroom and observe student activity. Help students if you notice they are not correctly following the steps. Ask students why they think measuring blood pressure is important and what exactly are they measuring. These questions help them start thinking in a way that helps them fill out the questions on the Measuring Blood Pressure Worksheet, as well as motivates them for Lesson 2, Blood Pressure Basics.

Formative Assessment: After demonstrating and explaining how to take blood pressure, help students correctly use the tools to measure blood pressure. While they are working in small groups, observe their progress to see if they comprehend how the technique works.

Post-Activity Assessment

Brainstorming Answers: To assess conceptions students may have about blood pressure, have them complete the questions on the Measuring Blood Pressure Worksheet, which will be answered in Lesson 2, Blood Pressure Basics. With an understanding of student's prior knowledge, this lesson can be modified to best meet student needs.

Safety Issues

Make sure that students do not inflate the blood pressure cuffs too much or for too long.

Troubleshooting Tips

Expect that for many students this is their first exposure to blood pressure measurement, besides perhaps seeing it on TV or in the movies. If possible, have in the classroom a few adults who are trained in taking blood pressure to help out with the groups.

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under National Science Foundation RET grant nos. 0338092 and 0742871. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.