Blood Pressure Lab Write-up: Produce a lab report for the body position activity of the Blood Pressure lab. Your report should be in nonnumeric, paragraph form. The data you need for the report is found in an Excel file posted on Canvas. The data includes subjects reported sex and age (decade, not specific year) as well as collected heart rates and data for sitting (resting) and recumbent blood pressure. 1. Write an Introduction Section (3 or 4 paragraphs). A brief overview of blood pressure should be included in this section. Don’t forget to include a citation when you provide information which is not common knowledge. For example, your text (Silverthorn, 2019), lab manual (Caldwell, Didomenico, Shearer, & Botten, 2019), or another reasonable source. Make sure to include brief explanations of the physiology underlying the measurement of blood pressure and how to interpret the blood pressure reading. State the hypotheses or predictions. 2. Methods. Write 2-3 paragraphs which give an overview of how you did your experiment. Cite our lab manual (Caldwell, Didomenico, Shearer, & Botten, 2019), and then concisely summarize how the data was collected. Write a paragraph describing your test subjects. How are they similar and how are they different? Write 1-2 paragraphs which gives a general overview of how you used the methods and baseline data to study the effects of changes in body position on blood pressure and heart rate. What is the independent variable of this experiment? The dependent variable? How are you analyzing the data (mean, standard deviation, confidence interval). 3. Results. Include at least one graph and a summary table or graph. You may need more than one. Any table or graph should have a descriptive title. Make sure you submit a summary table, not a restatement of raw data. I smile when I see calculated measures of central tendency (mean and median) and some measure of spread. Excel can do most of those calculations for you. Your graph should show class averages of the blood pressure component in your hypothesis for each body position. You should include a short narrative highlighting your data in this section. 4. Summary (4-5 paragraphs) Explain your data by using information you introduced in your introduction. Make sure to demonstrate you understand the underlying physiology explaining why blood pressure changes in response to changes in body position. Refer to your table and graph and point out any important data. If your results did not match your expected results, write a paragraph suggesting one reason your results might have been different from the expected results. Laboratory Manual for Human Physiology Biology 141L 8 th Edition – 2019 Grossmont Co llege Compiled by Sue Caldwell, Angela Didomenico, Allison Shearer, Ruth Botten Week 9-10: Blood Pressure Purpose: Blood pressure assessment (sphygmomanometry) is one of the most common physical tests performed in modern medical practice. This non-invasive procedure allows a health care professional to help determine the cardiovascular health of a patient by comparing recorded data against normal limits for a person’s age and sex. Today you will learn about the basic principles of sphygmomanometry and perform the procedure on your classmates. Introduction: Proper perfusion of vital organs is necessary for survival. The systemic arterial vessels must deliver blood to the peripheral capillaries in an efficient manner in order to meet the metabolic demands of the peripheral tissues. As the heart completes the ejection phase of ventricular systole the volume of blood ejected (the stroke volume) must be transmitted from the aorta to smaller arteries until this blood eventually reaches the capillary beds for gas exchange. This blood flow is directly proportional to the change in pressure along the vessel, and indirectly proportional to the resistance along the vessel. Resistance is determined by factors that would impeded or slow down blood flow. Blood viscosity, or thickness, and blood vessel diameter based on vasoconstriction and vasodilation are the key factors that determine resistance. The equation that expresses this relationship is F = ΔP. R Resistance is directly proportional to the viscosity of blood- therefore thicker blood will cause blood flow to decrease due to increased resistance. Resistance is indirectly proportional to the radius of the blood vessel raised to the fourth power (r4). Vasoconstriction, which decreases the vessel diameter, will increase resistance greatly and slow blood flow. Conversely, vasodilation, which increases the blood vessel diameter, will decrease resistance greatly and speed blood flow. The interplay between pressure changes and resistance determines the amount of stress a vessel wall is subjected to and the amount of work the left ventricle must due to open the aortic valve against aortic pressure. Blood pressure measurements are built on three physiologic principles: the cardiac cycle, aortic rebound, and elasticity of major blood vessels. Blood pressure is determined by applying pressure to the brachial artery and auscultating (listening to) the sounds of blood flow through the vessel. The sounds assessed through a stethoscope are called Korotkoff sounds and are based on how the blood is flowing through the compressed brachial artery. As pressure is applied to the brachial artery the blood flow through the vessel will be completely occluded, or blocked. As the pressure is slowly released from the sphygmomanometer the blood will slowly start to pass through the vessel, but it will be turbulent and make a lot of noise in the stethoscope. This first Korotkoff sound is the first “loud knock” heard in the stethoscope and is when the health care professional reads systolic pressure. Pressure is continually released from the cuff and blood flow will become “smoother” through the vessel because it is not squeezing through a small space. The blood flow sound will be more muffled (this is the second Korotkoff sound). When the blood finally flows smoothly through vessel the cuff is approximately equal to diastolic blood pressure. Most professionals read the diastolic pressure when the blood flow sounds disappear. (There are some variations in how health care professionals read diastolic pressure- some read at the last sound, others read at silence. This distinction makes a very small difference -a few mmHg- in diastolic pressure readings. As beginners, you will be reading at “silence” to make the procedure easier.) The two values obtained directly from this process are the systolic and diastolic blood pressures. The systolic blood pressure reflects the pressure in the major arteries as blood moves through the vessel due to the contraction of the left ventricle. The diastolic pressure reflects the pressure in the major arteries while the left ventricle is relaxed. When these values are recorded in a file they are written with the systolic pressure in mmHg over the diastolic pressure in mmHg: systolic/ diastolic Additional values can be calculated from the systolic and diastolic pressures that are also used to assess patient health are the pulse pressure and mean arterial pressure (MAP). The MAP must be high enough to supply tissues with sufficient oxygen, but a very high MAP may be indicative of cardiovascular stress and/or disease. The pulse pressure is calculated by subtracting the diastolic pressure from the systolic pressure (systolic-diastolic). (This number should be positive. If you calculate a negative pulse pressure check your original recordings and ensure that you have set up the equation properly). The MAP requires that you calculate the pulse pressure first. To calculate the MAP add 2/3( diastolic) pressure to 1/3 (systolic pressure) MAP = 2/3( diastolic blood pressure) + 1/3(systolic pressure) The pulse pressure can help a physician determine the relative stroke volume (blood ejected by the left ventricle) and the resistance in the arteries. The MAP helps determine the average rate of blood flow in the systemic arterial circuit as well as the relative stress the blood vessels are heart are subjected to. The MAP must be a minimum of 60mmHg to keep organs properly perfused, and normally ranges from 70-110mmHg. High MAPs indicate that the cardiovascular system is stressed and may not function normally. The following table shows current AHA (American Heart Association) guidelines. Classification Normal/Healthy Systolic Diastolic <120 and 180 or >110 Materials Needed: 1.Automatic sphygmomanometer 2. Stethoscope 3 Yoga mat or towel Experimental Methods: 1. With the subject in a seated (resting) position, attach the blood pressure cuff to the right arm of your volunteer. 2. Press start on the cuff to read blood pressure and heart rate of the volunteer. 3. Read the blood pressure and heart rate twice, then average the values. Be sure to average the systolic and diastolic pressures separately! 4. Repeat steps 1-3 with the left arm. 5. Have the volunteer lay down and stay quiet for 3 minutes. This is the recumbent position. 6. Attached the blood pressure cuff to the right arm of your volunteer. 7. Press start on the cuff to read blood pressure and heart rate of the volunteer. 8. Read the blood pressure and heart rate twice, then average the values 9. Repeat steps 6-8 on the left arm. Table 2: Calculations (mmHg) Condition Left arm (seated) Right arm (seated) Right arm (laying down) Left arm (laying down) Left arm (post exercise) Pulse Pressure MAP M/F Age (Decade) F M F M M F F F F F F F M m m F f f f f F F f 20 40 20 20 20 20 20 20 20 20 20 20 20 20 30 21 20 10 30 10 20 40 20 Resting HR 85 89 58 76 86 66 75 90 76 79 90 92 58 73 73 57 74 74 45 95 76 63 74 Right (Resting) Systolic Diastolic 112 84 142 89 118 52 124 87 126 92 102 67 121 84 98 68 101 55 92 67 114 78 110 70 113 59 110 72 129 83 107 68 100 74 78 56 120 73 114 82 109 70 113 79,5 92,5 65 Left (Resting) Systolic Diastolic 112 86 135 80 118 65 115 78 124 81 99 66 118 76 96 74 99 62 92 69 106 72 102 78 109 68 115 79 130 79 104 68 101 70 80 51 128 80 107 83 84 51 114,5 79 86 63 Recumbent HR 70 89 50 69 83 56 63 80 62 75 79 80 59 68 65 58 69 64 45 91 69 53,5 74 Right (Recumbent) Systolic 112 138 128 124 118 101 122 102 111 106 102 110 115 116 126 115 108 86 136 110 146 123 90 Right (Recumbent) Diastolic 78 79 64 86 83 59 79 70 55 69 68 72 60 72 71 66 68 57 77 71 98 79 62 Left (Recumbent) Systolic Diastolic 112 80 140 82 120 54 120 88 133 86 101 67 111 64 93 67 106 64 96 65 108 84 112 76 111 65 110 77 118 67 112 66 101 73 86 56 134 75 113 79 139 85 116 75,5 92 62 Mean Standard Deviation SE = Standard Error ME = Margin of Error 2 SE (Stand Error) Sara Yousif BIO 141L-3886 Blood Pressure Lab Write-up Part I: Introduction The ability to maintain normal blood pressure is crucial aspect of human life. Blood pressure refers to the pressure that blood puts on the arteries it flows through. This is dependent on many factors, including resistance to flow, cardiac output, and volume status of the individual. That flow is maintained ensures that the body receives blood that contains oxygen, nutrients, and many other important substances that are critical for survival. As resistance increases, the cardiac flow becomes more restricted. An example of this happening is when an individual has a plaque/cholesterol build-up in their arteries. To compensate for the decreased blood flow, there is an increased blood pressure. This is beneficial in acute settings, but longstanding high blood pressure can damage the arteries and heart muscle. Blood flow does not only change in response to disease. Blood flow changes based on our body position as well. The blood is evenly distributed throughout our bodies because there is no gravitational forces acting on our vascular system. If someone is lying down and suddenly stands up, the venous blood quickly flows into our lower limbs due to gravity, causing a rapid decrease in blood flow to the heart. The normal body response to this is rapid activation of baroreceptors that increase the pressure to restore flow. Individuals with certain diseases may not have this response and may experience orthostatic hypotension – fainting with position change. Due to its importance, blood pressure is routinely measured in the healthcare setting. It is measured using a sphygmomanometer and stethoscope. The sphygmomanometer device is wrapped around the patient’s upper arm and is inflated to put pressure on the brachial artery. The individual measuring the blood pressure places their stethoscope on the brachial artery and listens for Korotkoff sounds. These are sounds due to blood flowing through the brachial artery. The first, the systolic value, represents the pressure in the major arteries as blood is pumped out of the left ventricle. The diastolic pressure represents the pressure when the left ventricle is relaxed. Due to the importance of blood pressure, there are a range of normal values for individuals based on sex, age, and more. Our experiment aims to assess how blood pressure changes in the sitting versus supine position. Based on the physiology explained above regarding blood flow and gravity, we hypothesize that blood pressure will be lower when the patient is supine versus sitting. This hypothesis will be tested using participants’ position as the independent variable, and the resultant blood pressure as the dependent variable. Methods: We will be conducting the experiment on our colleagues, the demographics for which can be found in the results. We will be using an automatic sphygmomanometer, a stethoscope, and mat or towel. The participants will have the blood pressure cuff around their right arm in a seated position. The experimenter will press start and measure the blood pressure twice. The above sequence will be repeated on the same participant on the left arm. Following completion of both arms, the participant will lay down on the mat/towel for three minutes. The blood pressure cuff will then be attached to the right arm, and the machine will be started. The participant will get their left arm pressure read while supine following this. The measurements will all be taken twice, and their values will be averaged. These averages will be used to calculate the mean arterial pressure (MAP).