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.
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
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