PALS 2020 SHOCK QUESTIONS AND
ANSWERS
k Shock - Shock is defined as a physiologic state characterized by inadequate tissue perfusion to meet
metabolic demand and tissue oxygenation.
metabolic demand - what cardiac output is normally equal to
How can shock be characterized? - By inadequate peripheral and end organ perfusion. Also it can be
characterized by low cardiac output and decreased level of consciousness.
What types of shock can cause a high cardiac output? - Shock thats caused by sepsis or anaphylaxis
cardiac out put can be high
All types of shock can do what to organs? - Can result in impared function of vital organs such as the
brain (Decreased level of consciousness) and kidneys ( Low urine output and ineffective filtering)
What will occur if adequate o2 delivery to the tissues is not maintained? - Organ dysfunction
What are the major functions of the cardiopulmonary system? - Delivers oxygen to body tissues
Removes metabolic by products of cellular metabolism
Tissue hypoxia - This is present when a region of the body or an organ is deprived of adequate O2 supply.
What does cardiac output determine and vascular resistance determine? - Determines adequate blood
flow to the tissues
Cardiac output - The volume of blood pumped by the heart per minute is the product of stroke volume
and heart rate
Cardia output=Stroke volume X Heart Rate
Stroke volume - The volume of blood pumped by the ventricles with each contraction
Cardia output=Stroke volume X Heart Rate - According to this formula if the heart rate decreases, stroke
volume must increase commensurately to maintain the cardiac output.
How can cardiac output increase? - By an increase in heart rate, in stroke volume or both
What are the limits of increased cardia output produced by increasing heart rate? - If the rate is too fast,
as can happen with tachyarrhythmias, stroke volume can fall bc there is inadequate time to fill the heart.
As shock develops, compensatory mechanisms attempt to? - Attempt to maintain O2 delivery to vital
organs
, vasoconstriction - the constriction of blood vessels, which increases blood pressure.
Name the compensatory mechanisms - Tachycardia
Increased systemic vascular resistance (SVR) (vasoconstriction)
Increased strength of cardiac contraction (Contractility)
Increase in venous smooth muscle tone
The body's first action to maintain cardiac output is to? - Is to increase heart rate, or tachycardia, which
can increase cardiac output to a limited degree
When O2 delivery to the tissues is compromised what happens? - Blood flow is redirected or shunted
from nonvital organs and tissues ( like skin, skeletal muscles, gut, kidneys) to vital organs like brain, heart
What is another mechanism to maintain stroke volume and cardiac output? - Is increased strength of
cardiac contractions, or contractility, with more complete emptying of the ventricles
What else can support stroke volume? - Can be supported by increased venous smooth muscle tone,
improving venous return to the heart and preload
How is blood pressure determined - product of Cardiac output and Systemic Vascular Resistance (SVR)
As cardiac output decreases blood pressure is maintained by? - By an increase in SVR
pulse pressure - The difference between the systolic and diastolic blood pressure often narrows bc
increased SVR raises the diastolic pressure.
systolic pressure - Blood pressure in the arteries during contraction of the ventricles.
diastolic pressure - occurs when the ventricles are relaxed; the lowest pressure against the walls of an
artery
If cardiac output is inadequate, tissue perfusion is?
Signs of poor tissue perfusion? - Is compromised, even if blood pressure is normal.
Lactic acidosis and end organ dysfunction will be present even if blood pressure is normal
When SVR cannot increase further blood pressure? - Blood pressure begins to decline. Then O2 delivery
to organs is severely compromised
Myocardium - Muscular tissue of the heart
ANSWERS
k Shock - Shock is defined as a physiologic state characterized by inadequate tissue perfusion to meet
metabolic demand and tissue oxygenation.
metabolic demand - what cardiac output is normally equal to
How can shock be characterized? - By inadequate peripheral and end organ perfusion. Also it can be
characterized by low cardiac output and decreased level of consciousness.
What types of shock can cause a high cardiac output? - Shock thats caused by sepsis or anaphylaxis
cardiac out put can be high
All types of shock can do what to organs? - Can result in impared function of vital organs such as the
brain (Decreased level of consciousness) and kidneys ( Low urine output and ineffective filtering)
What will occur if adequate o2 delivery to the tissues is not maintained? - Organ dysfunction
What are the major functions of the cardiopulmonary system? - Delivers oxygen to body tissues
Removes metabolic by products of cellular metabolism
Tissue hypoxia - This is present when a region of the body or an organ is deprived of adequate O2 supply.
What does cardiac output determine and vascular resistance determine? - Determines adequate blood
flow to the tissues
Cardiac output - The volume of blood pumped by the heart per minute is the product of stroke volume
and heart rate
Cardia output=Stroke volume X Heart Rate
Stroke volume - The volume of blood pumped by the ventricles with each contraction
Cardia output=Stroke volume X Heart Rate - According to this formula if the heart rate decreases, stroke
volume must increase commensurately to maintain the cardiac output.
How can cardiac output increase? - By an increase in heart rate, in stroke volume or both
What are the limits of increased cardia output produced by increasing heart rate? - If the rate is too fast,
as can happen with tachyarrhythmias, stroke volume can fall bc there is inadequate time to fill the heart.
As shock develops, compensatory mechanisms attempt to? - Attempt to maintain O2 delivery to vital
organs
, vasoconstriction - the constriction of blood vessels, which increases blood pressure.
Name the compensatory mechanisms - Tachycardia
Increased systemic vascular resistance (SVR) (vasoconstriction)
Increased strength of cardiac contraction (Contractility)
Increase in venous smooth muscle tone
The body's first action to maintain cardiac output is to? - Is to increase heart rate, or tachycardia, which
can increase cardiac output to a limited degree
When O2 delivery to the tissues is compromised what happens? - Blood flow is redirected or shunted
from nonvital organs and tissues ( like skin, skeletal muscles, gut, kidneys) to vital organs like brain, heart
What is another mechanism to maintain stroke volume and cardiac output? - Is increased strength of
cardiac contractions, or contractility, with more complete emptying of the ventricles
What else can support stroke volume? - Can be supported by increased venous smooth muscle tone,
improving venous return to the heart and preload
How is blood pressure determined - product of Cardiac output and Systemic Vascular Resistance (SVR)
As cardiac output decreases blood pressure is maintained by? - By an increase in SVR
pulse pressure - The difference between the systolic and diastolic blood pressure often narrows bc
increased SVR raises the diastolic pressure.
systolic pressure - Blood pressure in the arteries during contraction of the ventricles.
diastolic pressure - occurs when the ventricles are relaxed; the lowest pressure against the walls of an
artery
If cardiac output is inadequate, tissue perfusion is?
Signs of poor tissue perfusion? - Is compromised, even if blood pressure is normal.
Lactic acidosis and end organ dysfunction will be present even if blood pressure is normal
When SVR cannot increase further blood pressure? - Blood pressure begins to decline. Then O2 delivery
to organs is severely compromised
Myocardium - Muscular tissue of the heart
