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  #1  
Old 08-27-2012
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Default Very Very High Yield Question

A 53-year-old caucasian female is admitted to the ER with hypotension.Her condition is considered very serious, and invasive hemodynamic monitoring is established.Bloop pressure measured by intra-arterial method is 72/46 mmHG.Her HR 120/min,regular.Pulmonary capillary wedge pressure (PCWP) estaimated using Swan-Ganz catheter is 6 mmHg.Mixed venous oxygen concentration(MVo2) is 16% (normal=15.5 vol%),Which of the following is the most likely cause of this patient's condition?

A.Cardiogenic shock
B.Volume depletion
C.Septic shock
D.Volume depletion
E.Right ventricular infarction
F.Hemorrhagic shock
G.Neurogenic shock

Please add reasoning to put up a nice discussion.Thanks
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Old 08-28-2012
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Septic shock? MVO2 is normal (it's low in hypovolemic and cardiogenic)
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Old 08-28-2012
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yes septic shock, the body is not using oxygen ... so MVO2 normal ....
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also, Normal PCWP rules out cardiogenic shock
and low B.P. due to vasodilation as a result of septic shock

Just my .02 bit!
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Old 08-28-2012
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I remember Goljan explaining it very well in his step 1 audios.
there is crazy flow through organs so they do not have enough time to extract oxygen, I do not remember though, was it septic or hypovolemic shock.

PCWP seems normal, HR is regular - i'd say the heart is fine - rule out cardiogenic shock.

Now I am stuck between volume loss (hemorrhage and volume depletion and septic shock) Kinda looks like more history should be provided...

Btw, you have Volume Depletion 2 times
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Quote:
Originally Posted by step_enhancer View Post
A 53-year-old caucasian female is admitted to the ER with hypotension.Her condition is considered very serious, and invasive hemodynamic monitoring is established.Bloop pressure measured by intra-arterial method is 72/46 mmHG.Her HR 120/min,regular.Pulmonary capillary wedge pressure (PCWP) estaimated using Swan-Ganz catheter is 6 mmHg.Mixed venous oxygen concentration(MVo2) is 16% (normal=15.5 vol%),Which of the following is the most likely cause of this patient's condition?

A.Cardiogenic shock
B.Volume depletion
C.Septic shock
D.Volume depletion
E.Right ventricular infarction
F.Hemorrhagic shock
G.Neurogenic shock

Please add reasoning to put up a nice discussion.Thanks
From my understanding that MVo2 increases in any case of shock(either the tissue can't extract O2 or because of low CO), but one thing against septic shock is the normal PCWP which should be low as septic shock cause diffuse vasodilation.
I would go with D or B
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Old 08-28-2012
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Correction D.Volume overload

rest Question is same

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Quote:
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Correction D.Volume overload

rest Question is same

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Would be B
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Old 08-28-2012
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Answer C.Septic Shock

Septic shock is a form of distributive shock that results from decreased systemic vascular resistance due to significant vasodialtion.Hyperynamic circulation can be observed during septic shock,leading to an elevated cardiac output.Normal MVo2 can be observed in patients with septic shock,results from hyperdynamic circulation and improper distribution of the cardiac output
Further Septic shock is characterized by low right atrial pressure and PCWP

A.The decreased PCWP rules out cardiogenic shock ,which typically have high PCWP due to high left atrial pressure

G and B .Neurogenic and hypovolemic shock will be accompanied by a low MVo2 due to increased oxygen extraction by hypoperfused tissues.

D and E. Volume overload and right ventricular infarction can be simply ruled out

This Question breaks down to understanding of PCWP and MV02
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Quote:
Originally Posted by step_enhancer View Post
Answer C.Septic Shock


G and B .Neurogenic and hypovolemic shock will be accompanied by a low MVo2 due to increased oxygen extraction by hypoperfused tissues.
can u please explain the extraction difference between septic and hypovolemic shock?
Or reference me somewhere.
This looks important,
Thanks
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Quote:
Originally Posted by DocSikorski View Post
can u please explain the extraction difference between septic and hypovolemic shock?
Or reference me somewhere.
This looks important,
Thanks
Septic shock is caused by gram negative bacteria infection,the LPS causes widespread vasodialtion and endothilial injury and dysfunction.This vasodilation causes peripheral pooling of blood and hyperdynamic flow , the organs badly perfused which leads to multi organ failure .Hypoperfusion of organ means less extraction of oxygen from incoming blood .Therefore in septic shock the MVo2-mixed venous oxygen level.

Whereas in Hypovolemic shock the peripheral circulation is working properly but the Volume of blood is less .Organ are perfused with whatever blood is left and the organs are extracting maximum oxygen .So now Mv02 is less than normal because of maximal o2 extraction by organs.

Hope it helps ,i do not have a reference for this
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Old 08-29-2012
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Quote:
Originally Posted by step_enhancer View Post
Septic shock is caused by gram negative bacteria infection,the LPS causes widespread vasodialtion and endothilial injury and dysfunction.This vasodilation causes peripheral pooling of blood and hyperdynamic flow , the organs badly perfused which leads to multi organ failure .Hypoperfusion of organ means less extraction of oxygen from incoming blood .Therefore in septic shock the MVo2-mixed venous oxygen level.

Whereas in Hypovolemic shock the peripheral circulation is working properly but the Volume of blood is less .Organ are perfused with whatever blood is left and the organs are extracting maximum oxygen .So now Mv02 is less than normal because of maximal o2 extraction by organs.

Hope it helps ,i do not have a reference for this
Thanks, I needed some re-brushing to this...

Its basically all the blood is deposited in the periphery so we have a pink patient with a warm skin...

In hypovolemic case, body tries to switch the perfusion to the most important organs, so patient is cold and pale
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Old 10-24-2013
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Default So how neurogenic shock has decreased MVO2

Thanks 4 da wonderful explanation which made a clear distinction between Septic & hypovolemic shock.

My confusion is about the distinction between Septic & Neurogenic
How come there is increased extraction of O2 in neurogenic shock? As this too has peripheral pooling of blood (I believe so, correct me here if I am wrong), due to loss of sympathetic tone.

Quote:
Originally Posted by step_enhancer View Post
Septic shock is caused by gram negative bacteria infection,the LPS causes widespread vasodialtion and endothilial injury and dysfunction.This vasodilation causes peripheral pooling of blood and hyperdynamic flow , the organs badly perfused which leads to multi organ failure .Hypoperfusion of organ means less extraction of oxygen from incoming blood .Therefore in septic shock the MVo2-mixed venous oxygen level.

Whereas in Hypovolemic shock the peripheral circulation is working properly but the Volume of blood is less .Organ are perfused with whatever blood is left and the organs are extracting maximum oxygen .So now Mv02 is less than normal because of maximal o2 extraction by organs.

Hope it helps ,i do not have a reference for this
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Old 06-30-2015
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Default goljan: LVEDP and ventricular compliance

Goljan rapid review says LVEDP is decreased in septic shock due to a decrease in left ventricle compliance( ventricle is stiff). i dont understand. can anyone explain? why is the ventricular compliance decreased?
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