Perfusion Flashcards
What is perfusion?
the flow of blood through arteries and capillaries delivering nutrients and oxygen to cells
What does perfusion require?
Perfusion requires the heart to generate sufficient cardiac output to transport blood through patent blood vessels for distribution in tissues throughout the body
What is the scope of perfusion?
Perfusion ranges from optimal perfusion to no perfusion
Changes in perfusion can be…
temporary, long-term, or permanent
Type of disorder that leads to changes in perfusion include:
acute conditions (MI, stroke, or shock) and chronic disorders (hypertension, heart failure, sickle cell, or hemophilia)
Conditions that specifically involve perfusion include:
neurologic (affecting vessels in the brain)
pulmonary (impaired blood flow to and from the lungs)
cardiovascular (interfering blood flow in the heart, arteries, and veins)
What are the causes of disorders related to perfusion?
congenital defects, genetic disorders, injury, inflammation, and infections
What does central perfusion require?
adequate cardiac function, blood pressure, and blood volume
What is cardiac output?
the amount of blood pumped by the heart each minute
What is systole?
phase of the cardiac where the ventricles contract
Central perfusion propels blood to all organs & tissues from patent _____ through ____ and returns the blood to the heart through patents ____
Central perfusion propels blood to all organs & tissues from patent arteries through capillaries and returns the blood to the heart through patent veins
When does central perfusion begin?
heart is stimulated by an electrical impulse that originates in the sinoatrial (SA) node and travels to the atrioventricular (AV) node
What is diastole?
the phase of the cardiac cycle when ventricles fill with blood
What is the normal cardiac output range?
4 to 6 L/min in the adult
What are two variables that influence cardiac output?
stroke volume and heart rate influence cardiac output
What is stroke volume?
the amount of blood ejected from each ventricle during contraction
What affects stroke volume?
preload and contractility affect stroke volume
What is preload?
amount of blood in the ventricles at the end of diastole aka diastolic pressure
What is contractility?
strength of myocardial contraction; greater the volume of blood in the ventricles (preload), greater the stretch of the myocardium & stronger the myocardial contraction
Cardiac output (CO) formula =
stroke volume x heart rate; normal range is 4-6L/ per minute in the adult
What is after load?
force the ventricles must exert to open the semilunar valves (aortic and pulmonic); influenced by systemic vascular resistance (SVR)
What is systemic vascular resistance?
resistance to the ejected blood created by the diameter of blood vessels receiving the blood
The smaller or more constricted the blood vessels, the …..
greater the pressure required to open the semilunar valves to eject the blood, increasing the heart’s workload (e.g. hypertension)
The larger or more dilated blood vessels, the…
less pressure required to eject the blood; reducing the workload on the heart
sympathetic nervous system ____ the heart rate, while the parasympathetic ____ the heart rate
sympathetic nervous system INCREASES the heart rate
the parasympathetic DECREASES the heart rate
What is tissue perfusion?
blood flow through arteries and capillaries to target tissues
What does tissue perfusion require?
patent vessels, adequate hydrostatic pressure, and capillary permeability
Lifespan considerations for infants
in infancy, the size of the heart in relation to the total body size is LARGER
systolic blood pressure after birth is low due to the weaker left ventricle of the neonate; develops strength and pressure rises during the first six weeks
Lifespan considerations for older adults
stiffening & thickening of the myocardial. tissue and decreased elasticity of arterial walls (age related)
these can lead to reduced cardiac efficiency (stroke volume & cardiac output); thus increasing oxygen demand
arterial stiffening causes increase in blood pressure
Older adults (population) risk factors
blood flow, stroke volume, cardiac output, and elasticity of arteries DECREASE
risk for heart failure, stiffening/thickening of heart tissues INCREASE
Social and environmental risk (population) factors
low family income, low educational level, access to health care, medical compliance, eating habits, depression, and stress
What populations have the highest risk for heart disease?
older adults, low income/educational level
Genetic risk (individual) factors
familial hypercholesterolemia, CAD, HF, diabetes, certain arrhythmias, hemophilia A&B, hemoglobinopathies (sickle cell)
Lifestyle (individual) risk factors
smoking, inactivity, unhealthy diet, obesity
Baseline history for perfusion
present health status, past health history, family history, person & psychosocial history (diet, exercise, smoking), medications or recreational drugs
Problem based history for perfusion
pain, fainting (syncope), dizziness, SOB (dyspnea), swelling (edema), bleeding or fatigue
What to include in assessment of symptoms?
location, duration, severity, description of symptoms, factors that alleviate or aggravate symptoms, and actions taken by patient
Examination findings include..
vital signs, inspection, palpation, auscultation
Primary prevention for perfusion:
promote health & prevent disease of heart & peripheral vascular health, including abnormal clotting and bleeding
healthy diet, physical activity, refrain from smoking, maintained blood pressure & weight
Secondary prevention
blood pressure and lipid screenings
Periods of confusion may be related to…
mini-strokes or transient ischemic attacks
in women, fatigue is…
an atypical symptom of MI
Perfusion removes ____ ; does not prevent _____, increase _____, or increase _____
Perfusion helps to remove waste products
Perfusion does NOT prevent clots, increase cardiac output, or increase mental alertness
Exercise in a cardiac rehab program is important because….
exercise increases flexibility, cardiac output, muscle mass, and blood flow through the arteries
Infarction is the actual ____ of the tissue with an _____ to regenerate
therefore, an MI is ____ of myocardial tissue
Infarction is the actual DEATH of the tissue with an INABILITY to regenerate
therefore, an MI is DEATH of myocardial (heart) tissue
Impaired central perfusion occurs when…
cardiac output is inadequate because it decreases the oxygenated blood reaching the bodily tissues (systemic effect)
Impaired central perfusion leads to…
ischemia, cell injury, and cell death
Most common subjective reported symptoms associated with impaired perfusion includes…
fatigue, SOB, pain
Most common clinical reported symptoms associated with impaired CENTRAL perfusion includes…
reduced cognition, anxiety, diaphoresis, increased respiratory rate
Most common clinical reported symptoms associated with impaired LOCAL perfusion includes…
reduced or absent pulse, cool or cold extremity, discoloration
Impaired tissue perfusion
reduced amount of blood or no blood reaching tissues; can lead to ischemia and cell death
Signs of impaired tissue in children and infants…
poor feeding, poor weight gain, failure to thrive, dusky skin color
Signs of impaired tissue in children and toddlers…
squatting (increases blood flow to the lungs) and fatigue
can also cause developmental delay (failure to meet milestones)
ECG waves are labelled as PQRST which stand for:
P wave: depolarization of atria
P-R internal: from beginning of P wave to beginning of QRS complex (aka time needed for atrial depolarization + time for impulses to travel through AV node to ventricles)
QRS complex: depolarization of ventricles
T wave: repolarization of ventricles electrical events slight preced mechanical events in heart
What is ischemia?
reversible cellular injury that occurs when the demand for oxygen exceeds supply due to a reduction or cessation in blood flow
What is infarction?
actual death of tissues with an inability to regenerate
e.g., myocardial infarction is the death of heart tissue
The amount of blood pumped by the heart each minute generates…
cardiac output
The flow of blood through arteries and capillaries, delivering nutrients and oxygen to cells is called….
Perfusion
Tissue/Local Perfusion is supplied by…
blood flowing from arteries to capillaries
What requires adequate cardiac function, blood pressure, and blood volume?
Central perfusion
What requires patent vessels, adequate hydrostatic pressure, and capillary permeability?
Tissue/Local Perfusion
First step of blood flow through the heart
right atrium receives venous blood from inferior/superior vena cave & coronary sinus
travels through the tricuspid valve into the right ventricle
Second step of blood flow through the heart
each contraction causes the right ventricle to pump blood through the pulmonic valve into the pulmonary artery and to the lungs
Third step of blood flow through the heart
oxygenated blood flows from lungs the left atrium via the pulmonary veins
Fourth step of blood flow through the heart
oxygenated blood passes through the mitral valve and into the left ventricle
Fifth step of blood flow through the heart
As the heart contracts, blood is ejected through the aortic valve into the aorta and thus enters the systemic circulation
The mitral valve is the tissue between ____ atrium & ____ ventricle
mitral valve is the gate between left atrium and left ventricle
The aortic valve…
pushes blood from the left ventricle into the aorta to be transported to the rest of the body (systemic circulation)
Chordae tendinae is the…
fibrous connective tissue commonly called the “heart strings”
Pulmonic valve is located…
between right ventricle & pulmonary artery
Aortic valve is located…
between left ventricle & the aorta
If you don’t have good conduction…
the ventricles won’t contract
Relative refractory period
heart muscle recovers excitability
Absolute refractory period
heart muscle does not respond to any stimuli
Re-polarization
contractile and conduction pathway cells regain resting polarized condition
How does the conduction system travel?
begins in SA node –> interatrial pathways –> AV node –> intermodal pathways –> bundle of His –> left & right bundle branches –> Purkinje fibers to ventricular contraction
Systole vs Diastole
systole = contraction of heart muscle (eject blood from ventricles)
diastole = relaxation of heart muscle (ventricles fill with blood)
Hypovolemia
very low volume of blood that leads to decreased blood pressure
Blood pressure is the…
Cardiac output x Systemic Vascular Resistance (SVR)
Systemic vascular resistance is the…
force opposing movement of blood
If a blood pressure cuff size is too large…
blood pressure shows a lower blood pressure, making the reading inaccurate
If a blood pressure cuff size is too small…
blood pressure shows a high blood pressure, making the reading inaccurate
Pulse pressure is the…
difference between systolic BP & diastolic BP
Mean arterial pressure is the…
average pressure within the arterial system
MAP = (SBP + 2 DBP) divided by 3
needs to be greater than 60 mm HG to perfuse vital organs
At what age should blood pressure screening begin?
beginning in infancy, BP screening is recommended at every-well child visit and at least annually
adult screening is recommended for every 2 years when BP is below 120/80 mm Hg
adult screening is recommended for every year if BP is between 120/80 mmHg or 139/90 mm Hg
How often should blood pressure screening occur?
Who should have lipid screening? How often?
for at risk men and women, lipid screening should be started at 20 years of age
men without risk are recommended lipid screening beginning at 35 years of age
women without risk are recommended lipid screening beginning at 45 years of age
no optimal frequency has been established
George Jones is a 59-year-old male who went to the emergency department with chest pain. He had experienced this chest pain for 30 minutes and it was not relieved after taking three nitroglycerin tablets 5 minutes apart. He reports the pain feels like “an elephant sitting on my chest. “He is diaphoretic and appears anxious. His vital signs are temperature 99° F, blood pressure 100/68 mm Hg, heart rate 110 beats/min, and respiratory rate 24 breaths/min. Mr. Jones is overweight and has type 2 diabetes mellitus, hyperlipidemia, and hypertension. He quit smoking last year after a 40- year history of one pack of cigarettes a day.. The nurse administers oxygen and draws blood for arterial blood gas analysis. A cardiac catheterization revealed a 90% blockage in one coronary artery. The cardiologist performed a balloon angioplasty and placed a stent in Mr. Jones’ blocked coronary artery to reestablish perfusion. Mr. Jones was admitted to the cardiovascular surgery unit and was ambulating within 24 hours after stent placement.
Develop a nursing care plan for perfusion
The nurse’s goals for Mr. Jones’ plan of care are to maintain effective cardiac output, control pain, relieve anxiety, and balance physical activity with energy-conserving activities. The nurse also played a significant role in Mr. Jones’ therapy by teaching him and his family about lifestyle changes, including diet and exercise, and the purpose of his prescribed medications, including adverse effects and the importance of following the medication regimen. Mr. Jones is referred for cardiac rehabilitation after discharge.
George Jones is a 59-year-old male who went to the emergency department with chest pain. He had experienced this chest pain for 30 minutes and it was not relieved after taking three nitroglycerin tablets 5 minutes apart. He reports the pain feels like “an elephant sitting on my chest. “He is diaphoretic and appears anxious. His vital signs are temperature 99° F, blood pressure 100/68 mm Hg, heart rate 110 beats/min, and respiratory rate 24 breaths/min. Mr. Jones is overweight and has type 2 diabetes mellitus, hyperlipidemia, and hypertension. He quit smoking last year after a 40- year history of one pack of cigarettes a day.. The nurse administers oxygen and draws blood for arterial blood gas analysis. A cardiac catheterization revealed a 90% blockage in one coronary artery. The cardiologist performed a balloon angioplasty and placed a stent in Mr. Jones’ blocked coronary artery to reestablish perfusion. Mr. Jones was admitted to the cardiovascular surgery unit and was ambulating within 24 hours after stent placement.
What individual risk factors & heath conditions put him at risk?
type 2 diabetes, hyperlipidemia, hypertension, being overweight, and smoking
