A dynamic illustration of filling pressure and its importance for the emergency room physician guy i

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A dynamic illustration of filling pressure and
its importance for the emergency room physician
(guy in the hat)
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Cardiac output determines venous return
determines cardiac output determines venous
return determines venous return determines
cardiac output
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The cardiovascular system is a system and it is
circular
Cardiac output and total peripheral resistance
determine arterial pressure arterial pressure
and resistance determine flow to the tissues
flow has to get back to the heart pressure
gradient from the tissues to the heart determines
how fast blood flows back to the heart blood flow
back to the heart determines filling of the
ventricles filling of the ventricles determines
cardiac output But
And so on, and so on, and so on Does it never
end, and how do we balance the cardiac output and
the inflow?
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(No Transcript)
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Cardiac pumping raises arterial pressure and
lowers venous pressure
Venous pressure changes less as the cardiac
output is increased because the venous
capacitance is much greater than the arterial
capacitance
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Change volume
Change Resistance
Venous return
Venous return
Cardiac output MUST equal venous return so we
plot them on the same graph. If it doesnt for a
short time, something will change.

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An increase in cardiac contractility can increase
cardiac output without change in central venous
pressure
dP/dt Cardiac work
Venous return
End diastolic pressure End diastolic fiber length
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Change the volume. Give a transfusion
Change peripheral resistance Give phenylephrine
a1 agonist
Decrease cardiac output No change in end
diastolic pressure
Increase cardiac output And the end diastolic
pressure
Note increased resistance causes increased
blood pressure increased afterload
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Heart failure is exceedingly complex
Decreased cardiac output Decreased blood
pressure Activation of the baroreceptor
reflex Elevation of the end diastolic
pressure Increase in extracellular fluid volume
(renal) Vasoconstriction (sympathetic,
Angiotensin II
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Relation between heart rate and cardiac output is
multi-faceted
Decrease filling time
COSVxHR
Inc. rate -gt inc. contractility