Circulatory Shock & Treatment Flashcards
what is the definition of circulatory shock
Generalized inadequate blood flow through the body to the extent that the tissues are damaged
heart failure vs. heart shock
failure: tissues aren’t supplied what they are needed, it can progress to shock and tissues are damaged
heart failure can lead to
shock
circulatory shock can be caused by
decreased in cardiac output
what cardiac abornoalities that decrease ability of heart to pump lead to cardiogenic shock
Myocardial infarction
Severe valvular dysfunction
Heart Failure
what factors taht decrease venous return can lead to schock
Decreased blood volume
Decreased vascular tone
Obstruction to blood flow
what situation can lead to circulatory shock without a decrease in cardiac output
hyperthyroidism
thyroid hormone does what
increases metabolic activity of tissues in body
how can hyperthyroidism cause shock
there is increased metabolism in all the tissues so they can’t get enough blood even with increased CO
what would happen in pt with hyperthyroidism, why do vessels dilate?
metabolism - local control
increased in metabolism with hyperthyroidism releases vasodilators and causes
vessels to dialte
what happens to peripheral resistance in individual with hyperthyroidism
falls tremendously (all the vessels are dilating)
what happens to venous return with individuals with hyperthrydoism
increases
what is CO in individuals with hyperthyroidism
very high
what are baroreceptors trying to do in pt with hyperthyroidism
lots of sympathetic stimulation but they can’t decrease vessels b/c of local stimulation
what is HR in individual with hyperthyroidism
high and high contractility
AV fistula stands for
arteriol venous fistula
what is AV fistula
blood vessel that connects arteries to veins
what does AV fistula do to total peripheral resistance?
put one vessel of low resistance there so total peripheral resistance will decrease
what does arterial pressure do with AV fistula
decrease
what are the two ways to have circulatory shock without decrease in CO
hyperthyroidism AV fistula (abnormal tissue perfusion patterns)
what is the end result of circulatory shock
tissue deterioration
once shock gets to a critical point, shock leads to
more shock
what kindo f loop once shock gets to critical point
positive feedback loop
positive feedback loop of shock leads to
death
what are the three stages of shock
Non-progressive Stage
progressive
irreversible
what is the non-progressive stage of shock
(Compensated stage)
Normal circulatory compensatory mechanisms will eventually cause full recovery without help of therapy.
what is the progressive stage of shock
in which, without therapy, shock becomes progressively worse.
what is the irreversible stage of shock
Shock has progressed to a stage where no known therapy will avert eventual death.
without therapy, progressive shock will
become worse
progressive shock can degrade into
irreversible shock
no matter what you do, if person has irreversible shock
you can’t save them
if you remove 10% of blood volume, blood pressure and CO do what
remain normal
why do BP and CO remain normal if you remove 10% of blood
baroreceptors kick in and make the the veins squeeze, more blood back to heart
how much blood does it take to lose to have a change in cardiac output
20%
why does cardiac output change before arterial pressure does (in regards to blood loss)
arterial pressure is controlled independently of anything else
body is set up to keep arterial pressure high - why? (even at the expense of other things)
need high arterial pressure always to get blood to brain
past 20% blood loss, what happens to Arterial pressure and CO
both fall
at what point do both arterial pressure and CO fall
after 20% blood bloss
what is plateau phase at about 35% blood loss due to?
CNS Ischemic response
if blood pressure falls realy low we get
massive sympathetic stimulation
if there is 35% blodo loss and you are in ischemic response, what is happening with blood vessels
they are almost all constricted
if you lose 40-45% of blood what happens
body can’t do anything about that, BP is 0
is there a number for the amoutn that there is critical shock
no there is not number, but there is a point where non-progressive shock goes into progressive shock
go through pg 7 and understand why each reflex contributes to non-progressive shock
pg 7
why is renin-angiotensin system activated in compensated shock
pressure is low so kidney sense and rekease renin
vasopressin is also known as
anti-diuretic hormone
vasopressin is a
vasoconstrictor
what does vasopressin do
puts water pores in collecting ducts of kidney so kidneys reabsorb all the water that might leave through urine
what kind of urine does hemorrhaging person have
concentrated
in shock in capillaries is ther net absorption or secretion
absorption back into capillaries
of the four capillary pressure what changes the most in shock
capillary pressure
if blood goes through capillary, rather than filtration and lymphatics removing it in shock, there is
re absorption from itnerstitium back into capillaries to try to increase blood volume
cardiac degeneration is what
heart itself begins to deteriorate
progressive shock does what to heart
cardiovascular deterioration
when heart starts to deteriorate in progressive shock what does that do
makes the shock worse - more positive feedback
sludged blood, what is it
happens with progressive shock
tissue levels of oxygen decrease
lactic acid and other things are released, CO2 not removed, pH acidic, the acidic pH causes sludged blood
acidic pH in blood causes
blood cells to agglutinate with each other
increased capillary permeability in late stage of schock:
movement of fluids from blood into tissues
what is released by ischemic tissue
endotoxin
endotoxin is released from what
dead gram negative bacteria in intestines
endotoxin does what to heart
inhibitory - depresses cardiac function
non-progressive vs. progressive shock depends on if
negative feedback mechanisms can overcome the positive feedback mechanisms
what are forms of hypovolemic shock
intestinal obstruction
severe burns
dehydration
hypovolemic shock is caued by
plasma loss
if you lose vasomotor tone (constant firing of vasoconstrictor area) what will happen
sympathetic nerves stop firing and blood vessels and veins will dilate
in neurogenic shock what do you see
increase vascular capacity
why does vascular capacity increase in neurogenic shock
because no more vasomotor tone
what happens to mean systemic circulatory pressure in neurogenic shock
decreased
what are causes of neurogenic shock
Deep general anesthesia - depression of vasomotor center
Spinal anesthesia - blocks sympathetic outflow.
Brain damage - brain concussion or contusion of basal regions of brain profound neurogenic shock.
in neurogenic shock you have decreased in CO etc without
losing any fluid
anesthesize spinal cord how can this cause neurogenic shock
can block sympathetic outflow
how can brain tdamage cause neurogenic shock
brain concussion or contusion of basal regions of brain profound neurogenic shock.
how can deep general anesthesia cause neurogenic shock
depression of vasomotor center
if pt is in deep general anesthesia what do you do for them if BP drops dramatically (neurogenic shock)
don’t give fluids, they have got enough fluids
want to constrict the arteries and veins - alpha antagonist like NE
does person in neurogenic shock have enough fluids
yes -the problem is the vessels are too dilated to get enough blood back to the heart. all the blood vessels are dilated
anaphylactic shock - what is this
due to allergic reaction and CO and arterial pressure fall dramatically
what is released into blood in anaphylactic shock
histamine
basophils
mast cells release
what happens to arteries in anaphylactic shock
dilation
arteriol dilation does what to arterial pressure in anaphylactic shock
decrease
what happens to vascular capacity in anaphylactic shock
increased capacity - decreased (I think it might actually be increased) compliance
what happens to capillary permeability in anaphylactic shock
increased permeability
what happens to venous return in anaphylactic shock
decreased
what is septic shock
Bacterial infection widely disseminated to many areas of the body
Many varieties of septic shock because of the many types of bacterial infections
most cases of septic shock are caused by
Gram-positive bacteria, followed by endotoxin-producing Gram-negative bacteria
what is Disseminated intravascular coagulation
micro blood clots everywhere in body - and the clots use up all the clotting factors so you can have hemorrhaging
what does DIC stand for
Disseminated Intravascular Coagulation
DIC can happen in
septic shock
endotoxic shock often occurs when
large segment of gut becomes strangulated & loses blood supply
when blood supply is reintroduced in endotoxic shock what happens
the endotoxins go everywhere, especially the eart
when endotoxin is released to body in endotoxic shock what happens to heart
similar to anaphylaxis - sever e shock, inhibits myocardial contractility
how can you treat shock (2 main treatments)
replacement therapy
sympathomimetics
describe replacement therapy for treatment of shock
plasma is best b/c it keeps fluid in capillaries - blood and plasma transfusion
what are sympathomimetics
sympathic like
what can be used as sympathomimetics
Ne
EPI
Dopamine
why is dopamine good for sympathomimetics
it has alpha, beta, properties depending on dose
and dopamine receptors in kidney to increase renalblood flow
sympathomimentcs are not useful in what kind of shock
hemorrhagic
