5th Lecture - Cardiovascular System for 200L Optometry and Pharmacy 2023-2024 PDF

GOOD MORNING CLASS 7/1/2024 Jesus is Lord 1  TODAY MARKS THE FIRST DAY TH OF THE 10 WEEK ST OF THE 1 SEMESTER OF THE 2023/2024 ACADEMIC SESSION (July 1 st – July 5 th 2024) 7/1/2024 Jesus is Lord 2 ...

GOOD MORNING CLASS 7/1/2024 Jesus is Lord 1  TODAY MARKS THE FIRST DAY TH OF THE 10 WEEK ST OF THE 1 SEMESTER OF THE 2023/2024 ACADEMIC SESSION (July 1 st – July 5 th 2024) 7/1/2024 Jesus is Lord 2  FIFTH LECTURE MONDAY 1 ST JULY, 2024 (8:00am – 10:00am) 7/1/2024 Jesus is Lord 3 CARDIOVASCULAR SYSTEM (PHS213 & OPT218) Dr. Eghe Osawaru AIHIE Department of Physiology, School of Basic Medical Sciences, College of Medical Sciences, University of Benin. Benin City, Nigeria. COURSE OUTLINE: CARDIOVASCULAR SYSTEM Definition and functions of the cardiovascular system Cardiac muscle Cardiac myoelectrophysiology Cardiac cycle Circulation of blood: cardiac output and regulation Blood pressure Haemodynamics and microcirculation Pulmonary, Coronary, Splanchnic and muscle circulation. Shock and cardiovascular changes in exercise. 7/1/2024 Jesus is Lord 5  BLOOD PRESSURE CONTD. 7/1/2024 Jesus is Lord 6  MEASUREMENT OF ARTERIAL BLOOD PRESSURE 7/1/2024 Jesus is Lord 7  INTRODUCTION It is not practical to use pressure recorders that require needle insertion into an artery for making routine arterial pressure measurements in human patients. Although these types of recorders are used on occasion when special studies are necessary. Instead, arterial blood pressure is clinically determined through indirect means. 7/1/2024 Jesus is Lord 8  Measurement of Arterial Blood Pressure Blood pressure is measured by two methods: 1. Direct method 2. Indirect method. Direct method is not used on humans 7/1/2024 Jesus is Lord 9  Indirect Method of Measuring Arterial Blood Pressure Indirect methods are used to measure arterial blood pressure in man. 1. Palpatory Method 2. The Auscultatory Method/Technique 3. The Oscillometric Method/Technique 4. Digital sensor monitoring technique 7/1/2024 Jesus is Lord 10  Indirect Method of Measuring Arterial Blood Pressure contd. The apparatus used to measure blood pressure in human beings is called sphygmomanometer. An instrument consisting of an inflatable cuff and a pressure gauge {sphygmus, pulse + manometer, an instrument for measuring pressure of a fluid}. The stethoscope is also necessary to measure blood pressure; it is used alongside the sphygmomanometer. 7/1/2024 Jesus is Lord 11 Figure 1: Mercury Sphygmomanometer and Stethoscope 7/1/2024 Jesus is Lord 12  Picture of Students taking blood pressure measurements 7/1/2024 Jesus is Lord 13  Indirect Method of Measuring Arterial Blood Pressure contd. Principle When an external pressure is applied over the artery, the blood flow through it is obstructed. The pressure required to cause occlusion of blood flow indicates the pressure inside the vessel. The brachial artery is usually chosen because of convenience. 7/1/2024 Jesus is Lord 14  Arterial blood pressure is measured with a sphygmomanometer (an inflatable cuff plus a pressure gauge) and a stethoscope. The inflation pressure shown is for a person whose blood pressure is 120/80. 7/1/2024 Jesus is Lord 15  Indirect Method of Measuring Arterial Blood Pressure contd. Procedure The subject is seated with the arm resting on the bench, the elbow approximately at the level of the heart. Wrap the pressure cuff in the upper 2/3 of the upper arm over the brachial artery. Cuff should not be too tight or too loose. 7/1/2024 Jesus is Lord 16  1. Palpatory Method Procedure First, the radial pulse is felt. While feeling the pulse, the pressure is increased in the cuff by inflating air into it with the help of a hand pump. While doing this, the mercury column in the sphygmomanometer shows the pressure in the cuff. 7/1/2024 Jesus is Lord 17  1. Palpatory Method contd. When pressure is increased in the arm cuff, the brachial artery is compressed and blood flow is obstructed. This causes the radial pulse to disappear. When the radial pulse disappears, the pressure is further increased by about 20 mm Hg. Then, the pressure in the cuff is slowly reduced by releasing the valve of the hand pump, i.e. the cuff is deflated slowly. 7/1/2024 Jesus is Lord 18  1. Palpatory Method contd. This is done by feeling the pulse and simultaneously watching the mercury column in the apparatus. Pressure is noted when the pulse reappears. This pressure indicates the systolic pressure. Disadvantage of palpatory method is that the diastolic pressure cannot be measured. 7/1/2024 Jesus is Lord 19  CLINICAL METHODS FOR MEASURING SYSTOLIC AND DIASTOLIC PRESSURES For routine arterial pressure measurements in human patients, the clinician determines systolic and diastolic pressures through indirect means, usually by the auscultatory method. The apparatus used to measure blood pressure in human beings is called sphyg-mo-manometer. 7/1/2024 Jesus is Lord 20  Types of Sphygmomanometers 1. Mercury Sphygmomanometers: The auscultatory method using a this device has been the reference standard for BP measurement for several decades. 2. Aneroid Sphygmomanometers: This device has an aneroid gauge that consists of metal bellows with a watch-like movement connected to a compression cuff. 3. Hybrid Sphygmomanometers – This device uses the auscultatory approach but replaces the mercury column with an electronic pressure gauge. 7/1/2024 Jesus is Lord 21 Figure 1: Mercury Sphygmomanometer and Stethoscope 7/1/2024 Jesus is Lord 22  Figure 2: Stethoscope 7/1/2024 Jesus is Lord 23  2. Auscultatory Method The auscultatory or Korotkoff method of measuring blood pressure (BP) has been the traditional approach for measuring systolic blood pressure and diastolic blood pressure. The observer must first palpate the brachial artery in the antecubital fossa and place the center of the bladder length of the cuff (commonly marked on the cuff by the manufacturer) so that it is over the arterial pulsation of the patient’s bare upper arm. 7/1/2024 Jesus is Lord 24  2. Auscultatory Method contd. The lower end of the cuff should be 2 to 3 cm above the antecubital fossa to allow room for placement of the stethoscope. The cuff should be pulled taut, with comparable tightness at the top and bottom edges of the cuff, around the bare upper arm. To assess the appropriate tightness, 1 finger should fit easily at the top and bottom of the cuff; 2 fingers should fit but will be very snug. 7/1/2024 Jesus is Lord 25  2. Auscultatory Method contd. The cuff should initially be inflated to at least 30 mm Hg above the point at which the radial pulse disappears. Disappearance of the radial pulse indicates that the brachial artery has been occluded and flow through the artery has stopped. The cuff is then gradually deflated (Cuff deflation should occur at a rate of 2 mm Hg per second to obtain an accurate estimate of BP). 7/1/2024 Jesus is Lord 26  2. Auscultatory Method contd. As the cuff is then gradually deflated, blood flow is re-established and accompanied by sounds that can be heard with a stethoscope held over the brachial artery at the antecubital space. Inflation that is too rapid can affect the BP reading, and a deflation rate that is too rapid (ie, faster than 2–3 mm Hg/s) can impede the ability to reliably identify the BP levels of the Korotkoff sounds. 7/1/2024 Jesus is Lord 27  2. Auscultatory Method contd. Korotkoff sounds are named after Nikolai Korotkoff, a Russian physician, who described them in 1905. Korotkoff sounds are believed to be caused mainly by blood jetting through the partly occluded vessel and by vibrations of the vessel wall. The jet causes turbulence in the vessel beyond the cuff, and this turbulence sets up the vibrations heard through the stethoscope. 7/1/2024 Jesus is Lord 28  2. Auscultatory Method contd. The sequence of Korotkoff sounds is as follows: a. Phase 1 - sudden appearance of sharp tapping sounds, considered to be Systolic Blood Pressure; b. Phase 2 - swishing sounds; c. Phase 3 - regular, louder sounds; d. Phase 4 - abrupt muffling of sounds; and e. Phase 5 - loss of all sounds, considered to be Diastolic Blood Pressure 7/1/2024 Jesus is Lord 29 Figure 3: Sounds heard through a stethoscope as the cuff pressure of a sphygmomanometer is gradually lowered. Sounds are first heard when cuff falls just below systolic pressure, and they cease when cuff pressure falls below diastolic pressure. Jesus is Lord 30 7/1/2024 Figure 4a: Auscultatory method for measuring systolic and diastolic arterial pressures. Jesus is Lord 31 7/1/2024 Figure 4b: Auscultatory method for measuring systolic and diastolic arterial pressures. Jesus is Lord 32 7/1/2024  2. Auscultatory Method contd. The auscultatory method for determining systolic and diastolic pressures is not entirely accurate, but it usually gives values within 10% of those determined by direct catheter measurement from inside the arteries. 7/1/2024 Jesus is Lord 33  3. Automated Oscillometric Method The auscultatory method of BP measurement is being replaced by the use of oscillometric devices in both clinical practice and research settings. Oscillometric devices are commonly used to measure BP in clinic, ambulatory, home, and hospital settings, with readings based on the amplitude of the oscillations recorded in the lateral walls of the upper arm (Muntner et al., 2019). 7/1/2024 Jesus is Lord 34  3. Automated Oscillometric Method contd. Semiautomated and automated devices that use the oscillometry method, which detects the amplitude of the Blood Pressure (BP) oscillations on the arterial wall, have become widely used over the past 2 decades (Muntner et al., 2019). These devices use a sphygmomanometer cuff, like the auscultatory method, but with an electronic pressure sensor to detect cuff pressure oscillations that occur when blood flows through an artery, often the brachial artery. 7/1/2024 Jesus is Lord 35  3. Automated Oscillometric Method contd. Most oscillometric devices estimate BP when the cuff is being deflated, but some devices obtain estimates on inflation. Mean arterial BP is estimated to be the cuff pressure when the oscillation amplitude is maximal, and then the SBP and DBP are computed. Oscillometric arterial pressure devices use specific electronic algorithms to inflate and deflate the cuff automatically and interpret the cuff pressure oscillations. 7/1/2024 Jesus is Lord 36  3. Automated Oscillometric Method contd. When the cuff is inflated, and its pressure exceeds systolic pressure, there is no blood flow in the artery and no oscillation of the cuff pressure. As the cuff is slowly deflated, blood begins to spurt through the artery, and the cuff pressure then oscillates in synchrony with the cyclic expansion and contraction of the artery. As the cuff pressure declines, the oscillations increase in amplitude to a maximum, which corresponds to the mean arterial pressure. 7/1/2024 Jesus is Lord 37  3. Automated Oscillometric Method contd. The oscillation amplitude then declines as the cuff pressure falls below the patient’s diastolic pressure and blood flows smoothly through the artery. Using device-specific algorithms, the cuff pressure oscillations are automatically converted into digital systolic and diastolic pressures signals, as well as heart rate, and displayed. 7/1/2024 Jesus is Lord 38  3. Automated Oscillometric Method contd. Oscillometric arterial pressure monitors require less skill than the auscultatory technique and can be used by the patient at home, avoiding the so-called white-coat effect that raises blood pressure in some patients when a health care professional is present. 7/1/2024 Jesus is Lord 39  3. Automated Oscillometric Method contd. These devices, however, must be calibrated for accuracy and can yield unreliable measurements in patients when the cuff size is inappropriate or in some abnormal circulatory conditions, such as severe arteriosclerosis, which increases stiffness of the artery wall. 7/1/2024 Jesus is Lord 40  Overview of Proper Seated Blood Pressure (BP) Measurement in the Office Key Steps for Proper BP Measurements Specific Instructions 1. Have the patient relax, sitting in a chair with feet flat on floor and Step 1: back supported. The patient should be seated for 3–5 min without Properly talking or moving around before recording the first blood pressure (BP) reading. A shorter wait period is used for some Automated prepare Office blood pressure (BP) devices. the patient 2. The patient should avoid caffeine, exercise, and smoking for at least 30 min before measurement. 3. Ensure that the patient has emptied his/her bladder. 4. Neither the patient nor the observer should talk during the rest period or during the measurement. 5. Remove clothing covering the location of cuff placement. 6. Measurements made while the patient is sitting on an examining table do not fulfill these criteria. 7/1/2024 Jesus is Lord 41 Key Steps for Proper BP Measurements Specific Instructions Step 2: Use 1. Use an upper-arm cuff blood pressure (BP) measurement device that has been validated, and proper ensure that the device is calibrated periodically. technique for 2. Support the patient’s arm (eg, resting on a BP desk). The patient should not be holding his/her measurements arm because isometric exercise will affect the blood pressure (BP) levels. 3. Position the middle of the cuff on the patient’s upper arm at the level of the right atrium (midpoint of the sternum). 4. Use the correct cuff size such that the bladder encircles 75%–100% of the arm. 5. Use either the stethoscope diaphragm or bell 7/1/2024 for auscultatory readings. Jesus is Lord 42 Key Steps for Proper BP Measurements Specific Instructions Step 3: Take 1. At the first visit, record blood pressure (BP) in both arms. the proper * Use the arm that gives the higher reading for measurements subsequent readings. needed for 2. Separate repeated measurements by 1–2 min. diagnosis and 3. For auscultatory determinations, use a palpated treatment of estimate of radial pulse obliteration pressure to estimate systolic blood pressure (SBP). Inflate the elevated BP/ cuff 20–30 mm Hg above this level for an hypertension auscultatory determination of the blood pressure. 4. For auscultatory readings, deflate the cuff pressure 2 mm Hg/s, and listen for Korotkoff sounds. *When a blood pressure (BP) measurement is obtained in 1 arm followed by the other arm and the BP is substantially lower in the second arm, it is possible that the difference could be caused by acclimation. In this circumstance, BP should be remeasured in the first arm. 7/1/2024 Jesus is Lord 43 Key Steps for Proper BP Measurements Specific Instructions Step 4: 1. Record SBP and DBP. If using the Properly auscultatory technique, record SBP document and DBP as the onset of the first of at accurate BP least 2 consecutive beats and the last readings audible sound, respectively. 2. Record SBP and DBP to the nearest even number. 3. Note the time that the most recent BP medication was taken before measurements. 7/1/2024 Jesus is Lord 44 Key Steps for Proper BP Measurements Specific Instructions Step 5: Use an average of ≥2 readings Average the obtained on ≥2 occasions to estimate readings the individual’s BP. Step 6: Provide patients their SBP/DBP Provide BP readings both verbally and in writing. readings to Someone should help the patient patient interpret the results. AOBP indicates automated office blood pressure; BP, blood pressure; DBP, diastolic blood pressure; and SBP, systolic blood pressure. Adapted from Mancia et al by permission of Oxford University Press on behalf of the European Society of Cardiology, copyright © 2013, The European Society of Hypertension (ESH) and European Society of Cardiology (ESC); from Pickering et al, copyright © 2005, American Heart Association, Inc; from Weir et al, copyright © 2014, American College of Physicians, all rights reserved, reprinted with permission of American College of Physicians, Inc; and from Whelton et al, copyright © 2017, by the American College of Cardiology Foundation and the American Heart Association, Inc. 7/1/2024 Jesus is Lord 45  Normal Arterial Pressures as Measured by the Auscultatory and Oscillatory Methods There is a progressive increase in pressure with age resulting from the effects of aging on the blood pressure control mechanisms. The kidneys are primarily responsible for long-term regulation of arterial pressure and it is well known that the kidneys exhibit definitive changes with age, especially after the age of 50 years. A slight extra increase in systolic pressure usually occurs beyond the age of 60 years. 7/1/2024 Jesus is Lord 46  Normal Arterial Pressures as Measured by the Auscultatory and Oscillatory Methods contd. This increase results from decreasing distensibility, or hardening, of the arteries, which is often a result of atherosclerosis. The final effect is a higher systolic pressure with considerable increase in pulse pressure. 7/1/2024 Jesus is Lord 47 Figure 5: Changes in systolic, diastolic, and mean arterial pressures with age. The shaded areas show the approximate normal ranges. Jesus is Lord 48 7/1/2024  ANY QUESTIONS PLEASE 7/1/2024 Jesus is Lord 49  A REMINDER: The best time to start reading was yesterday but the next best time to start reading is “TODAY” 05/03/2018 Jesus is Lord 50  MAKE GOOD USE OF THE REST OF TODAY AND THE WEEK 05/03/2018 Jesus is Lord 51  THANK YOU FOR LISTENING 7/1/2024 Jesus is Lord 52  THE END 7/1/2024 Jesus is Lord 53