Porth's Chapter 20
What is distributive shock?
Caused by excessive vasodilation with maldistribution of blood flow
What is obstructive shock?
Caused by obstruction of blood flow through the circulatory system
What is pulmonary congestion?
Common sign of left ventricular failure
What is inotrophy?
Contractile performance of the heart
Among the most common causes of heart failure are ?, ?, dilated cardiomyopathy, and ? heart disease.
Coronary artery disease, hypertension, valvular
? is the percentage of blood pumped out of the ventricles with each contraction.
Ejection fraction
What is systolic dysfunction?
Ejection fraction less than 40%
What is the primary physiologic result of obstructive shock?
Elevated right heart pressure
Ascites is a common manifestation associated with ? ventricular failure and long-standing elevation of systemic venous pressures.
right
Heart failure can be classified according to the ? of the heart that is primarily affected.
side
The ? is a function of preload, afterload, and myocardial contractility.
stroke volume
The heart rate is regulated by a balance between the activity of the ? nervous system, which produces an increase in heart rate, and the ? nervous system, which slows it down.
sympathetic, parasympathetic
Diastolic dysfunction can be aggravated by ? and can be improved by reduction in heart rate.
tachycardia
In hypovolemic shock, the main purpose of treatment is correcting or controlling the underlying cause of the hypovolemia and improving the perfusion of the tissues and organs of the body. Which of the following treatments is NOT a primary form of therapy for hypovolemic shock?
vasoconstrictive drugs
? shock is characterized by loss of blood vessel tone, enlargement of the vascular compartment, and displacement of the vascular volume away from the heart and central circulation.
vasodilatory
In persons with ventricular dysfunction, sudden death is caused most commonly by ? tachycardia or fibrillation.
ventricular
One of the many manifestations of left-sided heart failure is ?. It can be diagnosed by examination of the lips and mucous membranes.
Cyanosis
What are the physiologic signs and symptoms of cardiogenic shock?
Decrease in mean arterial blood pressures, rise in central venous pressure (CVP), and increased extraction of O2 from hemoglobin
What is cardiac reserve?
Ability to increase cardiac output during increased activity
Neurogenic shock, or spinal shock, is a phenomenon caused by the inability of the vasomotor center in the brain stem to control blood vessel tone through the sympathetic outflow to the blood vessels. In neurogenic shock, what happens to the heart rate and the skin?
Heart rate slower than normal; skin warm and dry
? is an uncommon type of heart failure that is caused by excessive need for cardiac output.
High-output failure
? heart defects are the most common cause of heart failure in children.
structural
The pathogenesis of multiorgan dysfunction syndrome is not clearly understood at this time. Supportive management is currently the focus of treatment in this disorder. What is not a major risk factor in MODS?
Respiratory dysfunction
What is the primary cause of heart failure in infants and children?
Structural heart defects
What is afterload?
The force that the contracting heart muscle must generate to eject blood from the filled heart
What is cyanosis?
bluish discoloration of the skin
With both systolic and diastolic ventricular dysfunction, ? are usually able to maintain adequate resting cardiac function until the later stages of heart failure.
compensatory mechanisms
Anaphylactic shock results from an ? mediated reaction in which vasodilator substances such as histamine are released into the blood.
immunologically
What is dyspnea?
labored breathing
Endurance athletes have ? cardiac reserves.
large
Diastolic ventricular dysfunction is characterized by a(n) ? ejection fraction by impaired diastolic ventricular relaxation leading to a decrease in ventricular filling, which ultimately causes a decrease in preload, stroke volume, and cardiac output.
normal
Central cyanosis is caused by conditions that impair ? of the arterial blood.
oxygenation
? dyspnea is a sudden attack of dyspnea that occurs during sleep
paroxysmal nocturnal
What is hypovolemic shock?
Caused by a decrease in blood volume
What is cardiogenic shock?
Caused by alteration in cardiac function
? is associated with impaired left ventricular filling that is due to changes in myocardial relaxation and compliance resulting in stiffness and loss of flexibility.
Aging
What is cardiac output?
Amount of blood the ventricles eject each minute
What is circulatory shock?
An acute failure of the circulatory system to supply the peripheral tissues and organs of the body with an adequate blood supply
? can be expressed as the product of the heart rate and stroke volume.
Cardiac output
What is high-output failure?
Failure that is caused by an excessive need for cardiac output
The rise in preload seen in systolic dysfunction is thought to be a compensatory mechanism to help maintain stroke volume via the ? mechanism despite a drop in ejection fraction.
Frank-starling
? has been defined as a complex syndrome that results from any functional or structural disorder of the heart that results in decreased pumping.
Heart failure
Anaphylactic shock is the most severe form of systemic allergic reaction. Immunologically medicated substances are released into the blood, causing vasodilation and an increase in capillary permeability. What physiologic response often accompanies the vascular response in anaphylaxis?
Laryngeal edema
The most common causes of ? ventricular dysfunction are acute myocardial infarction and cardiomyopathy.
Left
? is the most common cause of right ventricular failure
Left ventricular failure
? is caused by disorders that impair the pumping ability of the heart, such as ischemic heart disease and cardiomyopathy.
Low-output failure
When an acute event occurs and the circulatory system can no longer provide the body with adequate perfusion of its tissues and organs, cellular hypoxia occurs and the body goes into shock. What are the causes of shock in the human body?
Maldistribution of blood flow, hypovolemia, and obstruction of blood flow
What is endothelins?
Potent vasoconstrictors
Sepsis is growing in incidence in the US. Its pathogenesis includes neutrophil activation, which kills microorganisms. Neutrophils also injure the endothelium, releasing mediators that increase vascular permeability. What else do neutrophils do in sepsis?
Release nitric oxide
What is cor pulmonale?
Right heart failure occurs in response to chronic pulmonary disease
An important factor in the mortality of severe shock is acute renal failure. What is the degree of renal damage related to in shock?
Severity and duration of shock
What is orthopnea?
Shortness of breath when supine
What is hydrothorax?
Transduction of fluid into the pleural cavity
What is ascites?
Transudation of fluid into the pleural cavity
What is preload?
Volume or loading conditions of the ventricle at the end of diastole
What is cardiac asthma?
bronchospasm due to congestion of the bronchial mucosa
What is cheyne-stokes respiration?
periodic breathing characterized by gradual increase in depth followed by a decrease resulting in apnea
A gradual or rapid change in heart failure signs and symptoms resulting in a need for urgent therapy is defined as ? syndrome.
acute heart failure
? is the most dramatic symptom of acute heart failure syndromes.
acute pulmonary edema
In acute or severe left-sided failure, cardiac output may fall to levels that are insufficient for providing the ? with adequate oxygen.
brain
Measurements of ? are recommended to confirm the diagnosis of heart failure to evaluate the severity of left ventricular compromise and estimate the prognosis, and predict future cardiac events, and to evaluate the effectiveness of treatment.
brain natriuretic peptide (BNP)
? can be described as an acute failure of the circulatory system to supply the peripheral tissues and organs of the body with an adequate blood supply, resulting in cellular hypoxia.
circulatory shock
Systolic dysfunction commonly results from conditions that impair the ? performance of the heart (e.g., ischemic heart disease and cardiomyopathy), produce a ? (e.g., valvular insufficiency and anemia), or generate a ? (e.g., hypertension and valvular stenosis) on the heart.
contractile, volume overload, pressure overload
In systolic ventricular dysfunction, myocardial contractility is impaired, leading to a(n) ? in the ejection fraction and cardiac output.
decrease
In ? dysfunction, cardiac output is compromised by the abnormal filling of the ventricle.
diastolic
What are the signs and symptoms of heart failure?
fluid retention and fatigue
As venous distention progresses in right-sided heart failure, blood backs up in the ? veins that drain into the inferior vena cava, and the liver becomes engorged.
hepatic
Conditions that cause diastolic dysfunction include ?, the leading cause; ?, which impedes filling of the ventricle; and ?, which increases ventricular wall thickness and reduces chamber size.
hypertension, pericardial effusion or constrictive pericarditis, myocardial hypertrophy or hypertrophic cardiomyopathy
What is circulatory failure?
hypoperfusion of organs and tissues
? shock is characterized by diminished blood volume such that there is inadequate filling of vascular compartment.
hypovolemic
beta-adrenergic receptor blocking drugs are used to decrease ? dysfunction associated with activation of the sympathetic nervous system.
left ventricular
The development of ? constitutes one of the principle mechanism by which the heart compensates for an increase in workload.
myocardial hypertrophy
The most common cause of cardiogenic shock is ?
myocardial infarction
A defect in the vasomotor center in the brain stem of the sympathetic outflow to the blood vessels is known as ?
neurogenic shock
A major effect of right-sided heart failure is the development of ?
peripheral edema