Cardiovascular Parameters I PDF

Cardiovascular parameters I Practical 7 HUB 124 Tina Volkmann  Questions – what can you tell me? What is BP in your own words? How do you measure it in your work at hospital? – Digital? – Equipment used? What readings do...

Cardiovascular parameters I Practical 7 HUB 124 Tina Volkmann  Questions – what can you tell me? What is BP in your own words? How do you measure it in your work at hospital? – Digital? – Equipment used? What readings do you get? – Normal range – “Units”? – What do the numbers mean? Step by step procedure? – What are you doing? – What artery?  Heart rate (HR)/pulse rate Number of pulsations (contractions of the heart) per minute  1 Heartbeat (lubb-dubb) = 1 pulse beat Shows the heart is active Several locations for it to be taken – most common: radial pulse (radial point of the wrist) – what you feel is the ventricular systole  Blood pressure (BP) The pressure exerted by circulating blood upon the walls of blood vessels. When used without further specification, "blood pressure" usually refers to the arterial pressure in the systemic circulation. 2 components: – Systolic (arterial pressure exerted by the left ventricle; think: max. P) – Diastolic (arterial pressure when ventricle is in diastole, i.e. when the heart muscle is resting between beats and refilling with blood); min. P) in millimeters of mercury (mm Hg) Written as systolic/diastolic  Blood pressure (BP) It is one of the vital signs along with respiratory rate, heart rate, oxygen saturation, and body temperature. Average normal resting systolic (diastolic) blood pressure in an adult is approximately 120 mm Hg (80 mm Hg), abbreviated as "120/80 mm Hg". Chronically elevated BP  advancing arterial disease and  cardiac disease.  Measurement of BP Non Invasive methods (Routine method) The noninvasive auscultatory and oscillometric ( many automated BP devices)measurements are simpler and quicker than invasive measurements, require less expertise, have virtually no complications, are less unpleasant and less painful for the patient. Palpation - A minimum systolic value can be roughly estimated by palpation, most often used in emergency situations, but should be used with caution. A newer method has been suggested (Sahu & Bhaskaran, 2010) where both systolic and diastolic values can be obtained. Older method is written as e.g. 120/P -older method demonstrated: https://www.youtube.com/watch?time_continue=98&v=E4RELD0eGYE -newer method explained: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3087253/ Auscultatory - uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The mercury manometer, considered the gold standard, measures the height of a column of mercury, giving an absolute result without need for calibration and, consequently, not subject to the errors and drift of calibration which affect other methods. The use of mercury manometers is often required in clinical trials and for the clinical measurement of hypertension in high-risk patients, such as pregnant women.  Measurement of BP Listen (using a stethoscope) for the pulse sounds in the brachial artery and measuring the pressure with a sphygmanometer (baumanometer) Inflatable cuff pump pressure gauge and control valve Pumping up the cuff will compress and occlude the brachial artery no sound will be heard and no radial pulse felt As cuff slowly is deflated until the pressure in the cuff is slightly less than the maximal pressure in the artery (i.e. when the cuff pressure can be overcome by the systolic pressure)  now artery opens, blood rushes through sound heard! [Pressure gauge reading=systolic BP] Reducing pressure further, the sounds become more faint and disappear  pressure gauge reading when sound disappears = diastolic BP The sounds heard are known as Korotkoff sounds.  Laminar & Turbulent Flow Laminar flow Streamlined Outermost layer moving slowest and center moving fastest Turbulent flow Interrupted Rate of flow exceeds critical velocity Fluid passes a constriction, sharp turn, rough surface  Korotkoff Sounds Sound is created by turbulent flow of blood through the compressed vessel Sounds disappear when the vessel is no longer compressed by the pressure cuff and normal laminar flow resumes Drawings done in class  Method – pulse rate Pulse rate - volunteer (consent form) -watch 1. Sit comfortably and hold forearm with palm up towards you 2. Place the fingertips gently but firmly over the radial artery along the inside of the wrist, below the base of the thumb. Do not use the thumb (has a pulse of its own). 3. Count the number of beats per 15 sec. Multiply by four to get the pulse rate for a minute. No correction is necessary for a 60 sec count and accuracy is greater with a longer time. Pulse rate is in beats/min. 4. Continue the procedure three times and obtain an average value  Method – Blood pressure BP (indirect measurement) - volunteer (consent form) -sphygmomanometer - stethoscope 1. Wrap cuff around the subject’s arm above the elbow (horizontal level of the heart). 2. Place the stethoscope under the cuff on the brachial artery (inside of the arm; antecubital fossa) 3. Inflate the cuff to approximately 180mmHg by closing the valve and squeezing therubber bulb 4. Slowly release the air by opening the valve a little 5. Listen for a pulse in the brachial artery 6. As soon as you hear the first beat, record the systolic BP 7. At the first point where you no longer hear the puse, record the diastolic pressure. 8. Record BP as ration S/D Note: If you miss the reading, completely deflate the cuff and start again. The cuff cuts off blood flow.  Task Volunteer & consent form 1. Determine the pulse rate of a group member. Take readings: – At rest – sitting – At rest – standing – After exercise (30 sec scissor jumps) – sitting 2. Interpret your readings obtained 3. Determine the blood pressure of a group member. Take readings: – At rest – sitting – At rest – standing – After exercise (30 sec scissor jumps) – sitting Interpret your readings obtained Repeat the determinations at half minute intervals until pressure is back to resting level Construct a table to compare your data from your pulse rate to your blood pressure  HR (beats/min) BP (mmHg) Notes: Sitting Standing After exercising 0sec – 0sec – 0sec – 30- 30- 30- 60- 60- 60- 90- 90- 90- Etc. (till back to Etc. (till back to Etc. (till back to resting level) resting level) resting level) Blood pressure is regulated by blood volume, total peripheral resistance and cardiac rate. Factors affecting blood pressure are cardiac rate, stroke volume and total peripheral resistance (TPR). BP = CO x TPR CO = SV x HR thus BP = (SV x HR) x TPR