Blood Pressure Lecture PDF

Blood Pressure First Year Fundamentals of Nursing by Prof. Eman Talaat Elshamaa Professor of medical surgical nursing Objectives: At the end of this lecture the student should be able to:
Define the key terms.
Explain why blood pressure is measured
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Blood Pressure First Year Fundamentals of Nursing by Prof. Eman Talaat Elshamaa Professor of medical surgical nursing Objectives: At the end of this lecture the student should be able to:
Define the key terms.
Explain why blood pressure is measured
Describe physiology of arterial blood pressure.
List homodynamic effects on blood pressure.
Mention blood pressure equipments.
Explain how to measure blood pressure
List factors affecting blood pressure. Outlines
Definitions
Physiology of arterial blood pressure
Hemodynamic effects on blood pressure.
Factors affecting blood pressure.
Blood pressure equipments.
Measuring blood pressure.  Definitions Blood Pressure: It is the force exerted by blood against the walls of arteries Systole It is the period of heart muscle contraction. Systolic blood pressure It is the peak maximum pressure in the large arteries when the left ventricle pumps the blood into the aorta. Diastole It is the period of heart muscle relaxation. Diastolic Blood pressure It is the peak minimal pressure exerted on the wall of large arteries when the heart is relaxed Normal Range of blood pressure: 120/ 120/80 mmHg The standard unit: It is Millimeters of mercury (mmHg) Pulse Pressure: It is the difference between systolic and diastolic pressure = 40 mm Hg Hypertension It is the persistent blood pressure measurements above the normal 140/90 mmHg. Hypotension: it is a condition in which blood pressure measurements below the normal 100/65 mmHg.  Physiology of arterial blood pressure Blood pressure reflects the inter- relationships of homodynamic factors, factors, including:
Cardiac output
Peripheral resistance
Blood volume
Viscosity
Elasticity  1) Cardiac Output
It is the volume of blood pumped by the heart (stroke volume/SV) during one minute (heart rate/HR). CO=SV XHR
The blood pressure (BP) Is a product of the cardiac out put (CO) and peripheral vascular resistance (R). BP= Co X R 2) peripheral Resistance
Arteries and arterioles are surrounded by smooth muscle that contracts or relaxes to change the size of the lumen through which blood flows.
Thesize of arteries and arterioles changes to adjust blood flow to the needs of local tissues. 3) Blood Volume
It is the volume of blood circulating within the vascular system.
Mostadult have a circulating blood volume of 5000 ml, normally it remains constant. 4) Viscosity
Itis thickness or viscosity of blood which affects the ease with which blood flows through small vessels.
The hematocrite is the percentage of red blood cells in the blood, it determines blood viscosity 5) Elasticity
Normally the walls of an artery are elastic and easily distensible as pressure within the arteries increases, the diameter of vessel walls also increase. Arterial distensibility prevents
wide fluctuations in blood pressure. Homodynamic Effects on Blood Pressure Increased blood pressure due to
Increased cardiac output.
Increased peripheral vascular resistance.
Increased blood volume.
Increased viscosity.
Decreased arterial elasticity Decreased blood pressure due to
Decreased cardiac output.
Decreased peripheral vascular resistance.
Decreased blood volume.
Decreased blood viscosity.
Increased arterial elasticity. Factors influencing blood pressure
Age
Stress
Gender
Race
Daily variation
Medications
Activity 
Age ↑Age → ↑BP 
Stress
Anxiety, fear and pain can initially increase blood pressure
Why? because of increased heart rate, increased cardiac output, and increased peripheral vascular resistance. 
Gender
There is no clinically significant difference in blood pressure levels between boys and girls.
Afterpuberty, males have higher readings.
Withmenopause, women tend to have higher levels of blood pressure than men of the same age. 
Race
Theincidence of hypertension is greater in blacks than whites because of genetic and environ- mental influences. 
Daily variation
Variation may include: - a lower blood pressure during sleep, - a rise beginning at 4 to 6 AM, - the highest in the afternoon and - a fall in the evening. 
Medications
Some medications directly or indirectly affect BP.
Antihypertensive medications including diuretics, vasodilator, β- adrenergic blockers..etc…… ↓ BP
Narcotic analgesics …… ↓BP. Vasoconstrictors and intravenous fluids such as normal saline …… ↑BP. 
Activity
Olderadults often experience a 5 to 10 mm Hg fall in blood pressure about 1 hour after eating.
Blood pressure can be reduced for several hours after a period of vigorous exercise. Equipments of measuring BP: 1) A sphygmomanometer: it consists of a. An occlusive cloth cuff that encloses an inflatable rubber bladder. b. A pressure bulb with a release valve to inflate the cuff. c. Pressure manometer. manometer The types of manometer:
Aneroid
Mercury The aneroid Manometer ☻The
It has a glass-enclosed circular gauge containing a needle that registers millimeter calibrations.
Aneroid manometers have the advantages of being light weight, & portable. ☻ Mercury manometers
Theyare more accurate than aneroid manometers.
Themercury manometers are on upright tube containing mercury ☻Automatic or electronic sphygmomanometer Cuff length 2) A stethoscope It is instrument used to listen to the sounds produced by the heart, lungs and other body organs. Methods of measuring BP:
Palpatory method Systolic BP. Only
Auscultatory method Systolic & diastolic BP. Measuring Blood Pressure Behavioral and environmental conditions that can affect the reading: Room temperature too hot or cold Recent exercise Alcohol intake Nicotine use Muscle tension Bladder distension Background noise Talking (either patient or nurse) Arm position 
Person should be comfortably seated or lying down.
A drop of 20 mmHg or more from the recorded sitting blood pressure may indicate orthostatic (postural) hypotension. Orthostatic hypotension may be related to a decreased baroreceptor sensitivity, fluid volume deficit (e.g., dehydration), or certain medications (i.e., diuretics, antihypertensives). Symptoms of orthostatic hypotension include dizziness, lightheadedness, and falling. 
Person should have rested for 5- 10 minutes prior to the reading (No smoking, caffeine or vigorous exercise for 15- 15-30 minutes before). before). 
Ask client to empty bladder before evaluating and avoid talking to the client while taking the reading. (Each of these prevents elevating blood pressure prior to/during reading)
Place the mercury sphygmo- manometer at a flat horizontal surface. 
Squeeze excessive air out of the cuff. (Make sure the mercury level is at zero).
Expose upper arm. Notes: Don't measure BP from: 1)The arm on the affected side of a mastectomy patient (because it may decrease already compromised lymphatic circulation, worsen edema, and damage the arm). 2) The arm that is paralyzed, or injured. 3) The arm that have an IV cannula. 4) The arm with an arteriovenous fistula or hemodialysis shunt (because blood flow through the vascular device may be compromised). 
Support the patient’s arm extended in the way that the brachial artery is at level of the heart(Diastolic (Diastolic blood pressure may increase 10% 10% if arm is unsupported).
Position the cuff at heart level, so, it should fit snugly on upper arm. Make sure that it is 2-3 cm above the elbow flexion. 
The bladder inside the cuff should encircle 80% of the arm circumference in adults and 100% of the arm circumference in children younger than age 13.
A cuff that is too small may give a false or abnormally high blood pressure reading. Palpatory method
Locate the radial pulse.
Close valve, it should be easily opened.
Inflate the cuff, while feeling pulse on the artery.
At the time you cannot feel it anymore increase the pressure in the cuff (inflation) by 30 mmHg higher. 
Slowly release valve and note reading when pulse reappears (approximate systolic blood pressure).
Wait 30 second.  Auscultatory method
Locatethe brachial artery by palpation.
Placethe diaphragm of stethoscope on brachial artery about ½ -1 cm above the elbow (2 finger). 
Close bulb valve.
Inflate cuff to 30 mm Hg above reading where radial pulse disappeared.
Slowly release valve (so pressure drops about 2 to 3 mm Hg / sec). sec).
Identify systolic pressure reading when first clear Korotkoff sound is heard. 
Continue to deflate, and note reading when sound muffles (diastolic blood pressure).
Release the rest of the air from the cuff to zero
If reading is uncertain wait 30 seconds to one minute before re- measuring
Record the reading and report any abnormalities.  False--high Reading False
Cuff too small
Make sure that the cuff bladder is suitable for the arm size.
Cuff wrapped too
Tighten the cuff. loosely.
Neverdeflate the cuff
Slow cuff deflation, more slowly than 2 mm causing venous Hg/ sec. congestion in the arm or leg.
Read pressures with the
Tilted mercury column. mercury column vertical.
Postpone blood pressure
Measurement ”after measurement or help the patient has eaten, patient relax before taking ambulated, anxious, or pressures. flexed arm muscles  False--low Reading False
Incorrect position
Make sure the arm or of arm or leg leg is level with the patient's heart.
Mercury column
Read the mercury below eye level column at eye level.
Failure to notice
Estimate systolic auscultatory gap pressure by palpation (sound fades out for 10 to 15 before actually mm Hg, then returns) measuring it.
Inaudible low volume sounds 
When measuring BP from the thigh, wrap a cuff around the middle of the thigh, and put the stethoscope on the popliteal artery. Note: -The systolic pressure is 20 to 30 mmHg higher than in the brachial artery. - The diastolic pressure is the same. 
Blood pressure can be measured in forearm by placing appropriate size cuff around forearm 13 cm from elbow. Listen for korotkoff’s sounds over radial artery at wrist. Thank you How to_ Measure Blood Pressure.mp4