Patho Chapter 14: Altered Perfusion

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Perfusion

Forcing blood or other fluid to flow through a vessel and into the vascular bed of tissue to provide oxygen
what tissue needs to function and stay alive

Requirements for Effective Perfusion

Adequate ventilation and diffusion
Intact pulmonary circulation
Adequate blood volume and components
Adequate cardiac output
Intact cardiac control center
Intact parasympathetic and sympathetic nervous systems
Intact coronary circulation
Intact systematic circulation
Adequate tissue uptake of oxygen

Altered Perfusion

The inability to adequately oxygenate tissues at the capillary level

Factors that could alter perfusion

Ventilation-perfusion (VQ) mismatching
Impaired circulation
Inadequate cardiac output
Excessive perfusion demands

Ventilation-Perfusion Mismatching

Inadequate ventilation in well perfused areas of the lungs
Inadequate perfusion in well-ventilated areas of the lungs

Hypertension Pathophysiology

A progressive cardiovascular syndrome detected by an elevation in blood pressure and/or the presence of organ damage due to persistent blood pressure elevations

Hypertension Risk factors

Family history of HTN - Aging
DM - Obesity
Excessive dietary Na intake - Smoking
Excessive ETOH intake - Sedentary lifestyle

Hypertension Clinical Manifestations

Often asymptomatic 'silent killer'
When advanced, causes CNS changes:
Headache - Fatigue
New-onset blurred vision - Weakness
Confusion - Vomiting
Mental status changes - Nausea

Pulmonary edema and heart failure
Poor urinary output
Problems with eliminating urinary waste
Hematuria
Proteinuria

Hypertension Diagnostic Criteria

History and physical examination
Serial blood pressure measurements
Laboratory studies

Hypertension Treatment

Pharmacologic treatments
Lifestyle modifications
Weight reduction
Decreased alcohol, salt & saturated fat intake
Increased aerobic physical activity
Increased fruit and vegetable intake
Smoking cessation

Shock Pathophysiology

A profound hemodynamic and metabolic disturbance → circulatory failure and impaired perfusion of vital organs

Shock Causes

MI
Myocarditis
PE
Heart failure
Metabolic abnormalities

Cardiogenic Shock Clinical Manifestations

Pulmonary Edema
JVD
Hypotensive
Weak pulses
Oliguria

Amount/Volume (Hypovolemic)

Marked blood volume ↓
hemorrhage or plasma loss form intestinal obstruction, burns, physical trauma, or dehydration
↓ venous return
↓ cardiac output
↓ tissue perfusion

Amount/Volume (Hypovolemic) Causes

Hemorrhage or plasma loss from intestinal obstruction, burns, physical trauma, or dehydration

Sources of impaired perfusion

Massive systematic vasodilation (distributive)
Septic Shock
Neurogenic Shock
Anaphylactic Shock
Compensatory mechanisms: ↑ heart rate and contractility
which raises the demand for myocardial oxygen
vicious circle

Shock Clinical Manifestations

Tachycardia, tachypnea
Cool, clammy extremities with poor peripheral pulses
↓ arterial B/P (late sign indicates decompensation)
Cyanosis and/or pallor
Restlessness, apprehension, decreased mental function
Poor urinary output

Shock Diagnostic Criteria

History and physical examination
Response to fluids
Echo/EKG
CXR
Evidence of infection

Shock Treatment

Medical emergency airway, breathing, circulation
Correct underlying disorder if possible and then direct efforts at increasing the blood pressure to increase oxygen delivery to the tissues.

MI Pathophysiology

Oxygen supply inadequate to meet metabolic demands of cardiac cells

MI Major Risk Factors

Family history of CAD
Hypertension
Smoking
Blood cholesterol levels
Concurrent diabetes mellitus

MI Clinical Manifestations

Gender variability
Chest pain or a crushing pressure, often radiating to the left arm, shoulder, or jaw
Fatigue, weakness, syncope, anxiety
Dizziness, shortness of breath
Sweating, pallor
Indigestion
Nausea, vomiting

MI Diagnostic Criteria

History and physical examination
Troponin and myoglobin
ECG
Angiography

MI Treatment

Emergency management
Medical
Surgical
Long term treatment
Pharmacologic
Lifestyle modifications

Heart Failure Pathophysiology

Reflects an inadequacy of heart pumping so that the heart fails to maintain the circulation of blood
Result of:
Impaired cardiac functioning
Excessive workload demands
Left Heart Failure
Right Heart Failure

Heart Failure Treatment

Correct cause, if possible
Provide supplemental oxygen
Improve cardiac output (inotrops)
Reduce peripheral vascular resistance
Overall goal: improving quality of life

Stroke Pathophysiology

Any clinical event that leads to the impairment of cerebral circulation
Thrombotic, embolic, or hemorrhagic
Inflammation, ischemia, death of neurons
Cerebrovascular accident (CVA) versus transient ischemic attack (TIA)

Stroke Clinical Manifestations

Focal brain injury
Abrupt onset of hemiparesis
Vision loss or field deficits
Dizziness
Ataxia
Aphasia
Sudden decrease in the level of consciousness

Stroke Diagnostic Criteria

History and physical examination
Laboratory studies
CT scan

Stroke Treatment

Emergency management
Reduce cerebral edema and increased intracranial pressure
Rehabilitation

The lining of the heart that forms a first line of defense against infection and inflammation is called the:
a. Exocardium
b. Myocardium
c. Endocardium
d. Pericardium

D. Pericardium.

A complete cardiac cycle includes:
a. One contraction and one relaxation phase
b. Two contractions and one relaxation phase
c. One contraction and two relaxation phases
d. Two contractions and two relaxation phases

A. One contraction and one relaxation phase.

The _______ of the heart contracts and relaxes.
a. Myocardium
b. Pericardium
c. Endocardium
d. Osteocardium

A. Myocardium.

Jennifer tells you that she had to have an ECG yesterday. She asks what this test measures. You tell her that it measures:
a. The myocardium thickness.
b. The resting phase of the myocardium.
c. The blood level in the heart.
d. The electrical activity of the heart.

D. The electrical activity of the heart.

Match the following ECG characteristics to the source:
_____ P wave
_____ PQ interval
_____ QRS
_____ T
_____ U

a. Depolarization of the AV node and bundle fibers.
b. Depolarization of the ventricles.
c. Repolarization of Purkinje fibers.
d. Depolarization of the atria via the SA node.
e. Repolarization of the ventricles.

D. Depolarization of the atria via the SA node.
A. Depolarization of the AV node and bundle fibers.
B. Depolarization of the ventricles.
E. Repolarization of the ventricles
C. Repolarization of Purkinje fibers.

The following is considered the pacemaker of the heart:
a. AV node
b. BA node
c. SA node
d. Purkinje fibers

C. SA node

Raymond recently had a myocardial infarction and tells you that his cardiologist told him that his cardiac output is decreased. Raymond asks you what his cardiac output is. You tell him that it measures the:
a. Heart's efficiency to pump optimal amounts of blood.
b. Number of heartbeats a minute.
c. Amount of blood that leaves the heart with each beat.
d. The mean arterial pressure.

A. Heart's efficiency to pump optimal amounts of blood.

The systolic blood pressure measures:
a. The difference between the diastolic and systolic pressure.
b. The amount of pressure that remains in the aorta during the resting phase of the cardiac cycle.
c. The amount of pressure exerted during contraction of the left ventricle.
d. The mean arterial pressure.

B. The amount of pressure that remains in the aorta during the resting phase of the cardiac cycle.

These are located throughout the heart and they sense pressure changes in the arteries:
a. Purkinje fibers
b. RA node
c. SA node
d. Baroreceptors

D. Baroreceptors.

The three major factors responsible for clot formation called Virchow triad include all of the following except:
a. Vessel wall damage
b. Excessive clotting
c. Alterations in blood flow
d. Hypocoagulation

D. Hypocoagulation.

Dale recently had a physical and was told by his physician's assistant that he had atherosclerosis. Dale is not sure what this means and asks you to explain it to him. You tell Dale that it is:
a. Irregularly distributed lipid deposits in the inner lining of arteries.
b. An autoimmune mechanism.
c. A place where the vessel branches.
d. An outpouching in the vessel wall.

A. Irregularly distributed lipid deposits in the inner lining of the arteries.

David has had a myocardial infarction and has large infarct in the right atrium. An infarct is a(n):
a. Area of necrosis due to an acute episode of insufficient blood supply.
b. Bifurcation of the artery.
c. Outpouching of the vessel wall.
d. Area of collateral circulation on the cardiac muscle.

A. Area of necrosis due to an acute episode of insufficient blood supply.

Blood movement across the chambers of the heart is referred to as:
a. Shunting
b. Regurgitation
c. Stenosis
d. Dysrhythmia

A. Shunting.

Elmer has a valve that is unable to close properly and allows reflux of blood. This is called:
a. Shunting
b. Regurgitation
c. Stenosis
d. Dysrhythmia

B. Regurgitation.

Carie has an allergy to penicillin. Her provider mistakenly prescribed this medication for her infection. Shortly after taking the medication, Carie experienced a massive immune hypersensitivity response and moved into a state of shock. This type of shock is called:
a. Hypovolemic shock
b. Septic shock
c. Neurogenic shock
d. Anaphylactic shock

D. Anaphylactic shock.

anaphylactic shock

a condition of impaired tissue perfusion from shock because of a massive immune (type 1 or IgE-mediated) hypersensitivity response

aneurysms

local out pouching caused by weakness in the vessel wall

angina pectoris

chest pain or pressure that is intermittent and associated with myocardial ischemia, a reduction in blood flow to the coronary arteries caused by atherosclerosis often accompanied by vasospasm

atrioventricular node (AV)

`connects the conduction of impulses between the atria and ventricles

baroreceptors

located throughout the blood vessels and the heart; sense pressure changes in the arteries and alert the cardiac control center in the brainstem

bifurcations

regions wherein a vessel branches

blood pressure

the pressure or tension of the blood within the systemic arteries

cardiac cycle

refers to one contraction and one relaxation phase of the heart

cardiac dysrhythmias

a category of problems with maintaining an efficient heart rhythm, such as impairments of the sinoatrial (SA) node, atrioventricular (AV) node, cardiac cells that join the SA and AV nodes, or conduction systems int he atria or ventricles

cardiac output (CO)

the volume of blood pumped from the ventricles in 1 minute

congestive heart failure

occurs when the left ventricle of the heart is ineffective and blood backs up into the pulmonary vein and subsequently into the lung tissues; results in pulmonary edema; also called left heart failure

cor pulmonale

an alteration in the structure and function of the right ventricle caused by a primary disorder of the respiratory system

diastole

the relaxation of the heart that allows blood to fill the ventricles

diastolic blood pressure

the amount of pressure that remains in the aorta during the resting phase of the cardiac cycle

diastolic failure

failure that occurs with stiffness of the ventricle and loss of relaxation ability, which impairs the heart's ability to optimally fill with blood between cardiac contractions

disseminated intravascular coagulation (DIC)

a condition of uncontrolled activation of clotting factors resulting in widespread thrombi formation followed by depletion of coagulation factors and platelets; leads to massive hemorrhage

ecchymoses

bruises from superficial bleeding into the skin

embolus

any plug of material, such as thrombi, air, neoplasms, microorganisms, or amniotic fluid, that travels in the circulation and can obstruct the lumen of the vessel

endocardium

the inner lining of the heart that forms a continuous layer of endothelium that joins the arteries and veins to the heart, forming a closed circulatory system

fibrillation

a problem of the heart chamber vibrating instead of effectively pumping

fibrinolysis

a dissolution of blood clots

heart block

the obstruction of cardiac conduction, often at the atrioventricular node,leading to heart dysrhythmias

heart failure

reflects an inadequacy of heart pumping so that the heart fails to maintain the circulation of blood

heart rate

the number of heartbeats that occur in 1 minute

hematoma

large accumulations of blood in the tissue

hemorrhage

the loss of blood through the vessel wall

Homans sign

a test of foot dorsiflexion, which, in the presence of deep vein thrombosis, causes pain in the back of the lower leg

hypertension

an elevation in blood pressure commonly defined by a systolic pressure above 140mmHg or a diastolic pressure above 90mmHg

hypotension

a condition of reduced blood pressure

hypovolemic shock

the result of inadequate blood/plasma volume

infarct

an area of necrosis resulting from a sudden insufficiency of arterial or venous blood supply

infarction

the process of obstructing a blood vessel

isolated systolic hypertension

an elevation in systolic blood pressure without an elevation in the diastolic blood pressure

mean arterial pressure

an adequate measure of systemic tissue perfusion; is calculated as one third of the pulse pressure plus diastolic pressure

myocardial infarction

the total occlusion of one or more coronary arteries resulting in ischemia and death of myocardial tissue

myocardium

the thick muscular layer of the heart

neurogenic shock

a result of brain or spinal cord injury in which altered neuronal transmission leads to a loss of tension in the blood vessels, allowing unregulated vasodilation, decreased peripheral vascular resistance, and reduced blood pressure; oxygenated blood is not: shunted to vital organs, and perfusion to vital organs is reduced.

perfusion

the process of forcing blood to other fluid to flow through a vessel and into the vascular bed of a tissue for the purposes of providing oxygen and other nutrients.

pericardium

the outer covering of the heart,which holds the heart in place in the chest cavity, contains receptors that assist with the regulation of blood pressure and heart rate, and forms a first line of defense against infection and inflammation

petechiae

pinpoint hemorrhages of the skin or mucous membranes

pulse pressure

the difference between the systolic and diastolic blood pressure

purpura

the presence of diffuse hemorrhages of the skin or mucous membranes

regurgitation

the problem of incompetence of the valve; the valve is unable to properly close, allowing reflux of the blood

septic shock

a condition of altered perfusion by shock as the result of overwhelming systemic infection, often with gram-negative
bacteria (the endotoxin component) leading to inadequate perfusion of vital organs

shunting

the movement of blood across the atria or ventricles of the heart

sinoatrial (SA) node

the pacemaker of the heart, which generates a rhythmic impulse in the atria

stenosis

a problem in which narrowing of the valve occurs, aking it unable to open adequately

stroke

any clinical event, such as shock, cerebral hemorrhage, ischemia, or infarction, that leads to the impairment of cerebral circulation

stroke volume

the amount of blood pumped out of one ventricle of the heart in a single beat

systole

a heart contraction that forcefully moves blood out of the ventricles

systolic blood pressure

the amount of pressure exerted during contraction of the left ventricle and ejection of blood into the aorta

systolic failure

heart failure caused by a loss of contractile ability of the heart

thrombocythemia

a condition of excess platelets in the blood

thromboembolus

a situation in which a thrombus breaks off within a vessel and travels to another location in the body

thrombosis

a formation of a blood clot

transient ischemic attack (TIA)

a brief period of inadequate cerebral perfusion causing a sudden focal loss of neurologic function; full recovery of function usually occurs within 24 hours

ventilation-perfusion ratio

the relationship between inspired oxygen and the pulmonary circulation, which is responsible for transporting the oxygen to the heart to be pumped to the rest of the body. this is expressed as a ratio and is typically 0.8-0.9, where the rate of ventilation is usually less than the rate of perfusion

venous stasis

stagnation of blood in the veins with reduced venous return

Virchow triad

three major factors are responsible for thrombus formation; vessel wall damage, excessive clotting, and alterations in blood flow, such as turbulence or sluggish blood movement.

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