Pericardiocentesis question

[_expecto__]

Hey guys, can't figure out why during bloody effusion in pericardial sac during tamponade we see fluid instead of a clot, isn't blood outside the blood vessel supposed to agglutinate, is it the constant movement that prevent clotting? is it fibrynolisis, can't find answer anywhere? Thanks

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[The Knife & Gun Club]

You mean hemorrhage? I think it’s just that if you’re actively hemorrhaging into your pericardium the pressure would stop your heart before it gets the chance to clot.

If your taking about pericardial effusion that’s a different story...

 

[arcus]

Pericardial sac has about 50 mL of pericardial fluid which has similar features to plasma exudate non-tamponade. Depending on etiology of tamponade (Aortic dissection, Rupture of the ventricular free wall, Pericardial Disease), the pericardial fluid changes. Aortic dissection would be overt blood, rupture of ventricular wall would also be blood, pericardial disease could be several changes including serous fluid (pericardial effusion) or purulent pericarditis (infection).

I think you are referring to Hemorrhagic pericarditis which would obviously be blood thrown in with fibrinous or suppurative effusion, usually due to malignant neo-plasm to the pericardial space.

“Hemorrhagic pericarditis can also be found in bacterial infections, in persons with an underlying bleeding diathesis, and in tuberculosis. Hemorrhagic pericarditis often follows cardiac surgery and is occasionally responsible for significant blood loss or even tamponade, requiring re-operation. The clinical significance is similar to that of fibrinous or suppurative pericarditis.”

(Robbins & Cotran Basis of Pathology, Chapter 12, The Heart, p. 574).

Braunwalds is my go-to source for need to know detail on diseases of the heart. Check Braunwalds. One of the best sources available on all things heart

 

[alpinism]

It does clot.

That's why we do thoracotomies for tamponade secondary to traumatic injuries.

 

[CTFellowMD]

I don't think anyone here is really understanding his question.

It is classically taught that during a pericardiocentesis, one of the ways to differentiate pericardial blood from intracardiac blood is that blood aspirated from the pericardial sac will not clot. The reason for this is that pericardial blood is defibrinated from the cardiac motion.

You'll find plenty of papers and textbooks discussing this in more detail if you google.

 

[arcus]

It does clot.

...will not clot.

Well, I am so glad we have a solid answer on this important question!

I actually checked Braunwalds but since I own my copy in Inkling format, I can not copy / paste text from my tablet

So here is one source: Medscape

Pericardiocentesis: Overview, Indications, Contraindications

Confirmation of pericardial versus intracardiac needle tip placement
Various techniques have been described, but none is more reliable than real-time, direct ultrasonographic guidance. Note the following:

Clotting: Intracardiac blood forms a clot, whereas pericardial aspirate should not form a clot.​

 

[TypeADissection]

Ooh look at all you fancy people and fancy words like "clot" and "no clot." I'm the well-trained surgical monkey with a hammer that plays Wack-A-Mole. If I see blood around the heart on ultrasound during a trauma fast:

A. I'm putting a needle in it if patient's decompensating - then I'll give the blood to path and ask them to tell me what it is
or
B. I'm going to the OR to open the chest - then I'll give the blood to path and ask them to tell me what it is

Cheers.

 

[_expecto__]

Thanks guys, so my best guess is that during bloody effusion, when you drain fluid in pericardiocentesis its red, so you think: blood. first think is to check if it comes from pericardial sac or you just took some of our precious ventricular blood, you have 2 fast methods to differentiate, find out whats hematocrit in the blood you just drained and compare it with a sample of peripheral blood. If you punctured pericardial sac hematocrit will be lowered there that means less erythrocyte, less fibrinogen and lower susceptibility to clotting. Second method is pouring a bit of blood on the glass, ventricular will clot, the other will not clot, simple.
The second situation is blood hemorrhage, so basically this situation really suck to begin with, when you have aortal injury or some kind of aneurysm rupture theres really not much we can do, 50/50 chance the patient will die. So this is the blood with proper hematocrit so it does clot, just the clots are transferred to the back of the pericardium making it impossible to reach during pericardiocentesis. Also the heart movement prevents clotting by defibrination of the fluid, how does heart movement defibrinate this blood? its acknowledged that lack of movement and diffusive blood flow stimulate agglutination, so movement prevents? I don't know how, anyone?