NURS 3 (Exam 3) Class 12: Introduction to Perfusion
1. Summarize the physiology of the cardiovascular system as it relates to perfusion.
The Heart
● Cone-shaped organ; size of an adult fist
● Weight: less than 1 lb
● Location: between the vertebral column and sternum within the thoracic cavity
● Pericardium
0 Double layer of fibro-serous membrane
○ Covers the heart
○ Anchors the heart to surrounding structures
● 3 layers of muscles
0 Epicardium, myocardium, and endocardium
● 4 hollow chambers
0 Right atria → right ventricle → left atria → left ventricle
○ Each chamber is separated by a valve (atrioventricular OR semilunar)
● Heart sounds
0 Created by the closure of the heart valves; “lub-dub” heard on auscultation over the precordium
○ “Lub” - created when the atrioventricular valves close
○ “Dub” - created by the closure of the semilunar valves
○ Plus, heart sounds are also associated with the contraction and relaxation of the heart
○ Systole - phase of ventricular contraction
○ Diastole - phase of ventricular relaxation & refilling (starts as soon as S2 ends) ●
Additional heart sounds
○ 3rd heart sound
■ Heard AFTER the 2nd heart sound; called ventricular gallop
○ 4th heart sound
■ Heard immediately BEFORE the 1st heart sound; called atrial gallop
■ They are harsh blowing sounds caused by blood flow interruption within the heart, between the chambers, or
within the pulmonary and circulatory systems
○ These additional heart sounds may be heard in healthy individuals without heart disease or may be associated with
myocardial infarction OR heart failure
● Valvular disease
0 Additional heart sounds may be heard, such as clicks, snaps, ejection click, and friction rubs
Circulation
● Heart is referred to as double pump because each side of the heart receives and ejects blood ● The movement of blood
throughout the body depends upon 3 Circulatory Systems
Pulmonary Circulation
● Consists the right side of the heart, pulmonary artery, pulmonary capillaries, & pulmonary vein
● This is a low-pressure (15 mm Hg) system that begins with the right side of the heart
● Deoxygenated blood leaves the right ventricle and enters the lungs
● After oxygenation, the blood returns to the left atrium in preparation to supply oxygen to the body tissue
● When blood leaves R ventricle→ pulmonary artery→ pulmonary capillaries→ lung → pulmonary veins→ heart (left ventricle)
Systemic Circulation
● Consists the left side of the heart, aorta, and associated aortic branches
● This is a high-pressure system because it moves oxygenated blood to the peripheral body tissues
● Blood leaves L ventricle→ aorta→ tissues→ comes back through superior and inferior vena cava→ R atrium Body Vs Heart
● Body is perfused BEST during SYSTOLE
● Heart is perfused BEST during DIASTOLE
0 Prolonged tachycardia is problematic because since diastole is cut shorter the heart isn’t receiving as much blood
..1
,Coronary Circulation
● This is what perfuses the heart itself
● This is a network of vessels that supply oxygen and nutrients to the heart muscle
● Oxygenated blood is provided to the heart during diastole
● Blood flowing through these vessels are controlled by aortic pressure, heart rate, metabolic activity of the heart, and blood vessel
tone
Cardiac Cycle and Conduction System
● Made up of one contraction and relaxation of the heart (one heartbeat)
● HR: Normally occurs between 70-80x per minute
● The volume of blood within ventricles
0 In diastole, the volume increases to approximately 120 mL of blood (end diastolic)
○ End of systole, this volume decreases to approximately 50 mL of blood (end systolic)
○ The difference between these 2 values is the Stroke Volume; normally averages to 70 mL of blood for each heartbeat
● Cardiac Output
○ Amount of blood pumped by the ventricles into the pulmonary and systemic circulations in 1 minute
○ This value is calculated by multiplying the Stroke Volume (SV) by the Heart Rate (HR)
■ Cardiac Output = Stroke Volume x Heart Rate (normal = 4-8L/min)
○ Ejection Fraction = SV divided by end-diastolic volume
■ The number is a percentage, it should be 50-70% in a normal adult ■
Usually reported in echo reports
○ Indicates the heart’s ability to function as a pump
○ Ischemia (Oxygen-Deprived) - Body tissues that do not receive enough blood and oxygen
○ Cardiac Reserve - The ability of the heart to respond to changing demands and adjust cardiac output ●
What factors affect cardiac output?
○ Activity level, metabolic rate, physiological and psychological stressors, age, and body size
○ Heart Rate
■ HR is affected by direct and indirect autonomic nervous system stimulation through sensory or baroreceptors located in
the carotid sinus, aortic arch, venae cavae, and pulmonary veins
■ HR too fast = decrease filling time during diastole = decreased CO
■ Decreased HR = decreased CO
○ Contractility
■ How well the heart can contract
■ Ability of the heart muscle fibers to shorten
■ Sometimes the heart can’t snapback into shape (like old rubber band)
■ Overstretching of ventricle = decreased contractility = decreased CO
● An increase in preload for a prolonged period of time can cause overstretching of the ventricles and
eventually a decrease in CO ■ Increased contractility = increased CO ■ How can we increase contractility?
● Digoxin ○ Preload
■ Amount of heart muscle fiber tension or stretch that exists at the end of diastole and just before systole. ■
Affected by venous return and ventricular compliance
■ Decreased preload = decreased CO
■ Increased preload = overstretch of cardiac muscle = Heart Failure
○ Afterload
■ This is the force that the ventricles overcome to eject the blood from the ventricles
■ Cardiac muscle cells have the characteristic of self-excitation, or the ability to initiate and transmit impulses
■ Decreased afterload = decreased CO
■ Increased afterload up to a certain point = decreased CO ■
Ex. The sinoatrial node in the right atrium
..2
, ● The cells create action potentials (electrical activity that is the basis for the electrocardiography or
electrical tracing of the heart’s function)
* For both pre and afterload, too much or too little = decreased CO (we need a happy medium to maintain good CO)
Pulse
● Pulse - wave of blood created when the left ventricle contracts
● Apical pulse is the central pulse located at the heart's apex
0 Called the point of maximum impulse
● Peripheral pulses are located away from the heart ● Factors that affect the pulse rate
0 Age, gender, exercise, fever, medications, hypovolemia, stress, position changes, and pathology
Blood Pressure
● This is the measure of pressure exerted by the blood as it flows through the arteries
● Systolic BP - pressure when the ventricles contract
● Diastolic BP - pressure of the ventricles at rest
● Pulse Pressure - Difference between the diastolic and systolic pressures
0 Normally, pulse pressure is 40 mmHg; can be as high as 100 mmHg during exercise
● Factors that affect BP
0 Pumping action of the heart, peripheral vascular resistance, blood volume, length of blood vessels, blood viscosity
(thickness)
We can manipulate all these factors as needed (meds, pacemaker, etc)
● Pt has increased preload (give diuretics)
● Pt has decreased preload (give IV fluids, blood products)
● Pt has increased afterload (give beta blockers, antihypertensives)
● Pt has decreased afterload (give nitroprusside)
● Pt has decreased contractility (give digoxin)
● Pt has increased contractility (give metoprolol) Risk Factors for disease or failure
● Women’s risk of heart disease increases after menopause because of the drop in estrogen production
0 Being over age 55
○ Family history of heart disease
● Men are more likely to have a heart attack earlier in life than women
● Older Adult
0 Perfusion changes may be due to decrease in cardiac reserve, cardiac output, deconditioning, disease or the natural aging
process
○ Myocardial Hypertrophy - increase in the size of myocardial muscle cells, stiffening of heart valves, and a decrease in
sinoatrial node cells affecting heart rate
○ Vascular System changes include alterations in the layers and calcification of vessels
○ Pulmonary changes can affect cardiac functioning and include changes in the chest wall compliance, airway closure in
dependent lung areas, and increased lung volumes
○ Renal function changes include changes in kidney size and reduction in glomerular filtration rate
2. Differentiate common assessment procedures used to examine perfusion in adults.
Interview:
● Focus on current and past medical history, lifestyle, signs and symptoms, sleep and rest, self, and stress and coping. Chest Pain:
● Complaints of chest pain need to be assessed for:
○ Location ○ Severity
○ Quality or character ○ Aggravating and relieving factors
○ Timing ○ Associated symptoms
○ Setting or precipitating factors
Techniques:
● Inspection, palpation, percussion, auscultation
..3
, ● Begin with inspection of client’s head and neck, upper extremities, chest, abdomen, and lower extremities. Areas to include when
conducting an assessment of pt. with alteration in perfusion:
● Heart: following approach can be used
0 Apical pulse, cardiac rate and rhythm, heart sounds, and murmurs ● Pulse:
○ For peripheral pulses, nurse should also assess the corresponding pulse on the other side of the body ○ 9
sites for pulse assessments:
■ Temporal ■ Femoral
■ Carotid ■ Popliteal
■ Apical ■ Posterior tibial
■ Brachial ■ pedal/dorsalis pedis
■ Radial
● Blood Pressure:
0 BP cuff, sphygmomanometer, and stethoscope
■ Alternative equipment includes electronic sphygmomanometers and Doppler ultrasound stethoscopes ○
Depends on accurate identification of the Korotkoff sounds.
○ Nurse needs to ensure that BP is assessed correctly and without errors ○
Lifestyle considerations:
■ For older adult, consider client’s skin integrity, medications, and joint status before measuring
3. Describe diagnostic tests along with their nursing implications to determine the individual's perfusion status.Diagnostic tests: used to
determine cardiac function and perfusion status
● Serum cholesterol, triglycerides, and lipids
● Troponin, MB isoenzymes of creatine kinase
● Stress/exercise tests
● X-ray
● MRI
● CT
● Positron-emission tomography test
● Echocardiogram
● Transesophageal echocardiogram
● Cardiac catheterization w/ either coronary angiography or coronary arteriography ● Pericardiocentesis
● Electrocardiogram (ECG)
0 P wave: atrial depolarization and contraction
■ Impulse is from the SA node
■ Precedes QRS complex
■ Normally smooth, round, and upright
■ May be absent when the SA node is not acting as the pacemaker
■ Atrial repolarization occurs during ventricular depolarization and is usually not seen on the ECG.
○ PR interval: time required for the sinus impulse to travel to the AV node and into the Purkinje fibers ■
Measured from the beginning of the P wave to the beginning of the QRS complex.
● If no Q wave is seen, the beginning of the R wave is used
■ Normally 0.12 - 0.20 sec (up to 0.24 sec is normal in 65+ years)
■ If > normal, indicates delay in conduction from the SA node to the ventricles
■ Here the AV node puts a pause and allows ventricles to fill up
○ QRS complex: ventricular depolarization and contraction
■ 3 separate waves:
● Q wave : first negative deflection
● R wave : positive or upright deflection
● S wave : first negative deflection after the R wave
..4
1. Summarize the physiology of the cardiovascular system as it relates to perfusion.
The Heart
● Cone-shaped organ; size of an adult fist
● Weight: less than 1 lb
● Location: between the vertebral column and sternum within the thoracic cavity
● Pericardium
0 Double layer of fibro-serous membrane
○ Covers the heart
○ Anchors the heart to surrounding structures
● 3 layers of muscles
0 Epicardium, myocardium, and endocardium
● 4 hollow chambers
0 Right atria → right ventricle → left atria → left ventricle
○ Each chamber is separated by a valve (atrioventricular OR semilunar)
● Heart sounds
0 Created by the closure of the heart valves; “lub-dub” heard on auscultation over the precordium
○ “Lub” - created when the atrioventricular valves close
○ “Dub” - created by the closure of the semilunar valves
○ Plus, heart sounds are also associated with the contraction and relaxation of the heart
○ Systole - phase of ventricular contraction
○ Diastole - phase of ventricular relaxation & refilling (starts as soon as S2 ends) ●
Additional heart sounds
○ 3rd heart sound
■ Heard AFTER the 2nd heart sound; called ventricular gallop
○ 4th heart sound
■ Heard immediately BEFORE the 1st heart sound; called atrial gallop
■ They are harsh blowing sounds caused by blood flow interruption within the heart, between the chambers, or
within the pulmonary and circulatory systems
○ These additional heart sounds may be heard in healthy individuals without heart disease or may be associated with
myocardial infarction OR heart failure
● Valvular disease
0 Additional heart sounds may be heard, such as clicks, snaps, ejection click, and friction rubs
Circulation
● Heart is referred to as double pump because each side of the heart receives and ejects blood ● The movement of blood
throughout the body depends upon 3 Circulatory Systems
Pulmonary Circulation
● Consists the right side of the heart, pulmonary artery, pulmonary capillaries, & pulmonary vein
● This is a low-pressure (15 mm Hg) system that begins with the right side of the heart
● Deoxygenated blood leaves the right ventricle and enters the lungs
● After oxygenation, the blood returns to the left atrium in preparation to supply oxygen to the body tissue
● When blood leaves R ventricle→ pulmonary artery→ pulmonary capillaries→ lung → pulmonary veins→ heart (left ventricle)
Systemic Circulation
● Consists the left side of the heart, aorta, and associated aortic branches
● This is a high-pressure system because it moves oxygenated blood to the peripheral body tissues
● Blood leaves L ventricle→ aorta→ tissues→ comes back through superior and inferior vena cava→ R atrium Body Vs Heart
● Body is perfused BEST during SYSTOLE
● Heart is perfused BEST during DIASTOLE
0 Prolonged tachycardia is problematic because since diastole is cut shorter the heart isn’t receiving as much blood
..1
,Coronary Circulation
● This is what perfuses the heart itself
● This is a network of vessels that supply oxygen and nutrients to the heart muscle
● Oxygenated blood is provided to the heart during diastole
● Blood flowing through these vessels are controlled by aortic pressure, heart rate, metabolic activity of the heart, and blood vessel
tone
Cardiac Cycle and Conduction System
● Made up of one contraction and relaxation of the heart (one heartbeat)
● HR: Normally occurs between 70-80x per minute
● The volume of blood within ventricles
0 In diastole, the volume increases to approximately 120 mL of blood (end diastolic)
○ End of systole, this volume decreases to approximately 50 mL of blood (end systolic)
○ The difference between these 2 values is the Stroke Volume; normally averages to 70 mL of blood for each heartbeat
● Cardiac Output
○ Amount of blood pumped by the ventricles into the pulmonary and systemic circulations in 1 minute
○ This value is calculated by multiplying the Stroke Volume (SV) by the Heart Rate (HR)
■ Cardiac Output = Stroke Volume x Heart Rate (normal = 4-8L/min)
○ Ejection Fraction = SV divided by end-diastolic volume
■ The number is a percentage, it should be 50-70% in a normal adult ■
Usually reported in echo reports
○ Indicates the heart’s ability to function as a pump
○ Ischemia (Oxygen-Deprived) - Body tissues that do not receive enough blood and oxygen
○ Cardiac Reserve - The ability of the heart to respond to changing demands and adjust cardiac output ●
What factors affect cardiac output?
○ Activity level, metabolic rate, physiological and psychological stressors, age, and body size
○ Heart Rate
■ HR is affected by direct and indirect autonomic nervous system stimulation through sensory or baroreceptors located in
the carotid sinus, aortic arch, venae cavae, and pulmonary veins
■ HR too fast = decrease filling time during diastole = decreased CO
■ Decreased HR = decreased CO
○ Contractility
■ How well the heart can contract
■ Ability of the heart muscle fibers to shorten
■ Sometimes the heart can’t snapback into shape (like old rubber band)
■ Overstretching of ventricle = decreased contractility = decreased CO
● An increase in preload for a prolonged period of time can cause overstretching of the ventricles and
eventually a decrease in CO ■ Increased contractility = increased CO ■ How can we increase contractility?
● Digoxin ○ Preload
■ Amount of heart muscle fiber tension or stretch that exists at the end of diastole and just before systole. ■
Affected by venous return and ventricular compliance
■ Decreased preload = decreased CO
■ Increased preload = overstretch of cardiac muscle = Heart Failure
○ Afterload
■ This is the force that the ventricles overcome to eject the blood from the ventricles
■ Cardiac muscle cells have the characteristic of self-excitation, or the ability to initiate and transmit impulses
■ Decreased afterload = decreased CO
■ Increased afterload up to a certain point = decreased CO ■
Ex. The sinoatrial node in the right atrium
..2
, ● The cells create action potentials (electrical activity that is the basis for the electrocardiography or
electrical tracing of the heart’s function)
* For both pre and afterload, too much or too little = decreased CO (we need a happy medium to maintain good CO)
Pulse
● Pulse - wave of blood created when the left ventricle contracts
● Apical pulse is the central pulse located at the heart's apex
0 Called the point of maximum impulse
● Peripheral pulses are located away from the heart ● Factors that affect the pulse rate
0 Age, gender, exercise, fever, medications, hypovolemia, stress, position changes, and pathology
Blood Pressure
● This is the measure of pressure exerted by the blood as it flows through the arteries
● Systolic BP - pressure when the ventricles contract
● Diastolic BP - pressure of the ventricles at rest
● Pulse Pressure - Difference between the diastolic and systolic pressures
0 Normally, pulse pressure is 40 mmHg; can be as high as 100 mmHg during exercise
● Factors that affect BP
0 Pumping action of the heart, peripheral vascular resistance, blood volume, length of blood vessels, blood viscosity
(thickness)
We can manipulate all these factors as needed (meds, pacemaker, etc)
● Pt has increased preload (give diuretics)
● Pt has decreased preload (give IV fluids, blood products)
● Pt has increased afterload (give beta blockers, antihypertensives)
● Pt has decreased afterload (give nitroprusside)
● Pt has decreased contractility (give digoxin)
● Pt has increased contractility (give metoprolol) Risk Factors for disease or failure
● Women’s risk of heart disease increases after menopause because of the drop in estrogen production
0 Being over age 55
○ Family history of heart disease
● Men are more likely to have a heart attack earlier in life than women
● Older Adult
0 Perfusion changes may be due to decrease in cardiac reserve, cardiac output, deconditioning, disease or the natural aging
process
○ Myocardial Hypertrophy - increase in the size of myocardial muscle cells, stiffening of heart valves, and a decrease in
sinoatrial node cells affecting heart rate
○ Vascular System changes include alterations in the layers and calcification of vessels
○ Pulmonary changes can affect cardiac functioning and include changes in the chest wall compliance, airway closure in
dependent lung areas, and increased lung volumes
○ Renal function changes include changes in kidney size and reduction in glomerular filtration rate
2. Differentiate common assessment procedures used to examine perfusion in adults.
Interview:
● Focus on current and past medical history, lifestyle, signs and symptoms, sleep and rest, self, and stress and coping. Chest Pain:
● Complaints of chest pain need to be assessed for:
○ Location ○ Severity
○ Quality or character ○ Aggravating and relieving factors
○ Timing ○ Associated symptoms
○ Setting or precipitating factors
Techniques:
● Inspection, palpation, percussion, auscultation
..3
, ● Begin with inspection of client’s head and neck, upper extremities, chest, abdomen, and lower extremities. Areas to include when
conducting an assessment of pt. with alteration in perfusion:
● Heart: following approach can be used
0 Apical pulse, cardiac rate and rhythm, heart sounds, and murmurs ● Pulse:
○ For peripheral pulses, nurse should also assess the corresponding pulse on the other side of the body ○ 9
sites for pulse assessments:
■ Temporal ■ Femoral
■ Carotid ■ Popliteal
■ Apical ■ Posterior tibial
■ Brachial ■ pedal/dorsalis pedis
■ Radial
● Blood Pressure:
0 BP cuff, sphygmomanometer, and stethoscope
■ Alternative equipment includes electronic sphygmomanometers and Doppler ultrasound stethoscopes ○
Depends on accurate identification of the Korotkoff sounds.
○ Nurse needs to ensure that BP is assessed correctly and without errors ○
Lifestyle considerations:
■ For older adult, consider client’s skin integrity, medications, and joint status before measuring
3. Describe diagnostic tests along with their nursing implications to determine the individual's perfusion status.Diagnostic tests: used to
determine cardiac function and perfusion status
● Serum cholesterol, triglycerides, and lipids
● Troponin, MB isoenzymes of creatine kinase
● Stress/exercise tests
● X-ray
● MRI
● CT
● Positron-emission tomography test
● Echocardiogram
● Transesophageal echocardiogram
● Cardiac catheterization w/ either coronary angiography or coronary arteriography ● Pericardiocentesis
● Electrocardiogram (ECG)
0 P wave: atrial depolarization and contraction
■ Impulse is from the SA node
■ Precedes QRS complex
■ Normally smooth, round, and upright
■ May be absent when the SA node is not acting as the pacemaker
■ Atrial repolarization occurs during ventricular depolarization and is usually not seen on the ECG.
○ PR interval: time required for the sinus impulse to travel to the AV node and into the Purkinje fibers ■
Measured from the beginning of the P wave to the beginning of the QRS complex.
● If no Q wave is seen, the beginning of the R wave is used
■ Normally 0.12 - 0.20 sec (up to 0.24 sec is normal in 65+ years)
■ If > normal, indicates delay in conduction from the SA node to the ventricles
■ Here the AV node puts a pause and allows ventricles to fill up
○ QRS complex: ventricular depolarization and contraction
■ 3 separate waves:
● Q wave : first negative deflection
● R wave : positive or upright deflection
● S wave : first negative deflection after the R wave
..4
