Module 4 Flashcards
3 Factors Affecting Stroke Volume
Contractility
Pre load
After load
Types of shock
Anaphylactic Pulmonary Cardiogenic Hypovolemic Septic
Scope of Perfusion
Optimal –> Suboptimal –> No Perfusion
Types of Hypertension
Primary
Secondary
Primary Hypertension
Hypertension that occurs without an identified disease
Obscure causes
Secondary Hypertension
Hypertension that occurs as a result of an identified disease
Short Term Regulators of Blood flow
Neural
Cardiovascular Center –> receives input from baroreceptors + chemoreceptors
Hormonal
RAAS System –> angiotensin II, aldosterone
Vasopressin (ADH)
Epinephrine/Norepinephrine
Local
Blood vessel autoregulation
Longterm Regulators of Bloodflow
Kidneys
resp for filtering blood, reabsorption, excretion
Target-Organ Damage from Hypertension
Heart
Brain
Eyes
Kidneys
Cholectamine
Chemical messenger released into blood in responset to stress
Examples of Cholectamine
Epinephrine
Norepinephrine
Contractility
force of myocardial contraction
determined by preload
Afterload
Resistance that must be overcome to eject blood from the left ventricle
impacted by blood viscosity, vasoconstriction
Mean Arterial Pressure
Average pressure of the arterial system through one cardiac cycle
Used as an indicator of perfusion
calculated by: cardiac output x total peripheral resistance
~60-100 mm Hg
Systolic vs. Diastolic Blood Pressure
Systolic BP = blood pressure in arteries during ventricular contraction
Diastolic BP = blood pressure in arteries during ventricular relaxation
Pulse Pressure
Measures pulsing nature of blood flow
Calculated by: systolic BP - diastolic BP
~40 mm HG
Peripheral Vascular Resistance
Resistance to blood flow in the systemic arteries
Heart Conduction System
SA Node –> AV Node –> AV Bundle –> Purkinje Fibers
Autoregulation
ability of organs to maintain optimal perfusion despite changes in blood pressure
local effect
High Blood Pressure
systole = >140 diastole = >90
Diuresis
excretion of water/extracellular fluid by kidneys
Natriuresis
excretion of sodium by kidneys
Consequences of High SBP
leads to left ventricular hypertrophy
heart failure
Hypertensive Crisis
systole = >180 diastole = >110
includes hypertensive urgency and hypertensive emergency
Secondary Hypertension Risk Factors
Kidney disease
Adrenal Cortical disease
Pheochromocytoma
Coarctation of aorta
Consequences of High DBP
decreased coronary perfusion
increases total peripheral resistance
Secondary Hypertension Risk Factors
Kidney disease
Adrenal Cortical disease
Pheochromocytoma
Coarctation of aorta
Kidney Disorders
Acute glomerulonephritis
Acute renal failure
Acute urinary obstruction
Atherosclerosis of renal blood vessels
Total Peripheral Resistance
Total resistance to blood flow in systemic circulatory system
Angiotensin II Effects
vasoconstrictor
promote reabsorption of sodium in proximal convoluted tubule
stimulate adrenal cortex to produce aldosterone
Aldosterone Effects
promote reabsorption of sodium in DCT
promote excretion of potassium in DCT
Hypertension & Blood Vessesls
Atherosclerosis Hypertrophy Inward Remodeling Vascular Stiffness Rearctation
Pheochromocytoma
catecholamine-secreting tumors of adrenal chromaffin cells
continually release norepinephrine/epinephrine
Coarctation of Aorta
congenital issue
narrowing of the aorta lumen
Chromaffin cells
Secreting cells of the adrenal medulla
Effects of norepinephrine/epinephrine
Norepinephrine - vasoconstriction, increase heart rate (increase in cardiac output), increase myocardial contraction
Epinephrine - inhibit insulin release, promotes glycolysis, decrease sweating, vasoconstriction blood vessels
Perfusion
flow of blood from arteries –> capillaries –> tissue
can be calculated as blood flow/mass or (ml/min)/kg of unit mass
optimal perfusion = when tissue receives sufficient blood flow to meet metabolic need (this varies)
Signs/symptoms of peripheral perfusion
capillary refill <2-3 seconds temperature of extremities skin tone pulse rates urine production bowel movements
Baseline history
trying to obtain a general assessment of a patient’s health and relevant lifestyle factors
medication recreational/illicit drug use chronic conditions smoking diet exercise
Problem-based history
reported symptoms that could indicate impaired perfusion
dyspnea - shortness of breath syncope - fainting edema dizziness pain
Factors affecting blood pressure readings
caffeine bowel movement faulty equipment poor assessment technique pain medication (prescription or over-the-counter)
Physiological Changing of Aging
reduced arterial compliance (arteries stiffen and elastin is replaced with collagen)
reduced arterial patency (atherosclerosis, occlusions)
reduced baroreceptor sensitivity (reduced neural response)
reduced cardiac output
reduced renal blood flow (higher blood volume)
increased peripheral resistance
venous valves less effective –> peripheral edema
Measuring blood pressure
person has rested five minutes thirty minutes after exercise or caffeine sitting position, both feet on the floor arm at chest or heart level take two readings
Factors affecting central perfusion
reduction in cardiac output structural defects (heart valves, myocardial tissue) viscosity of blood (increases afterload) poor tissue perfusion to myocardium conduction issues
Factors affecting tissue perfusion
arterial compliance
occlusion, obstruction in arteries
poor central perfusion
blood viscosity
Modifiable Risk Factors
Diet (alcohol, sodium, fat intake)
Sedentary lifestyle
Obesity
Smoking
Non-modifiable Risk Factors
Race
Age
Sex
Genetics (Family History)
What are Risk Factors?
habits or characteristics that make an individual more at risk for certain conditions/disease
Effects of Hypertension on blood vessels
Atherosclerosis Hypertrophy Vascular Stiffness Inward Remodeling Rarefaction
Target Organ Damage
Brain - Stroke, TIA Eyes - Retinopathy Kidneys - Kidney Disease Arteries - Atherosclerosis Heart - left ventricular hypertrophy, heart failure, aortic aneurysm, myocardial infarction, coronary artery disease
Angina
severe chest pain accompanying an ischemic attack
Hypoxia
reduced oxygen levels in blood –> weakens cells
Arrhythmia
irregular heartbeat due to an issue in the electrical conduction system
Pathophysiology Interrelated Concepts
etiology - cause of disease
pathogenesis - onset/development of disease
clinical manifestation - signs/symptoms of disease
Hypoxia
decreased amount of O2 in tissue cells
Hypoxemia
decreased amount of O2 in arterial blood
Variations in Perfusion Impairment
duration (acute v. chronic)
type (central v. tissue)
degree (ischemia v. infarction)
Determinants of Perfusion
Blood pressure
Cardiac output
Peripheral vascular resistance
Shock
Critical condition that occurs when there is inadequate blood volume to supply the bodily tissues/organs
central perfusion can no longer support tissue perfusion. various causes.
Areas of the cardiovascular center
Cardioinhibitor –> parasympathetic, decrease heart rate, vagus nerve
Cardioaccelerator –> sympathetic, increase heart rate, cardiac accerelator nerve
Vasomotor –> sympathetic, vasoconstriction,
Diagnostic Studies
Blood tests
ECG
Radiographic Studies
Cardiac Stress Tests
Preload
volume of blood in the ventricles at the end of diastole
affected by venous return of blood to heart
Blood Vessel patency
openness/unobstructedness of artery
diameter of lumen
What triggers renin release?
reduced sodium levels in blood reduced blood volume reduced perfusion to kidneys sympathetic nervous system stimulation angiotensin II
Factors contributing to resistance
blood viscosity length of blood vessel radius of blood vessel arterial compliance arterial patency
Types of arteries
large arteries –> more elastin > smooth muscle (higher compliance ex: aorta)
small + medium arteries –> more smooth muscle > elastin (autoregulation of bloodflow)
Hypertensive urgency
Blood pressure >180/110 but no signs of end-organ damage.
Treated with medication.
Hypertensive emergency
Blood pressure >180/110 with end-organ damage.
Will require emergency medical interventions.
Arterial compliance
ability of arteries to respond to changes in pressure
increased pressure –> arteries distend
decreased pressure –> arteries retract
Physiological variations in blood pressure
age –> increased blood pressure
stress –> temporary increase in blood pressure
circadian rhythm –> time of day affects blood pressure
Baroreceptor response to blood pressure
baroreceptor = located in the arch of the aorta + carotid bodies
mechanoreceptors that respond to stretch
increased blood pressure = increased stretch = increased firing to the CV center –> parasympathetic activation –> vasodilation
decreased blood pressure = decreased stretch = decreased firing to the CV center –> sympathetic stimulation –> vasoconstriction
Circulatory System Components
heart = pump
arterial system = transport blood away from heart. pressure reservoir. elastic vessels.
venous system = transport blood towards heart. blood reservoir. compliant vessels. have valves.
capillary beds = site of gas exchange.
Determinants of Perfusion
blood pressure
cardiac output
peripheral vascular resistance
Prehypertension
<120-139/80-89
Stage 1 Hypertension
<140-159/90-99
Stage 2 Hypertension
> 160/100
Treatment goals for hypertension
reduce modifiable risk factors
goal BP for non-diabetic patients: <140/90
goal BP for diabetic patients: <130/80
