#Epi 106 - ICU Primary Snippet - ROTEM: Platelet Dysfunction, Heparin and Hyperfibrinolysis

So I guess today's snippet is about viscoelastic assays that we use in ICU for testing the coagulation pathways.

So Maddy, the question is with regards to viscoelastic assays, can you please describe the expected alterations and underlying mechanisms resulting from the following? A, platelet dysfunction.

B, therapeutic heparin use.

C, hyperfibrinolysis.

And you can use either Teg or Rotem in your answer as a test that we choose to test these different settings.

Yeah, so I'm going to speak about Rotem because in the institutions that I've worked at, that's the main viscoelastic test that's used, but I know some other places do use Teg.

I thought we'd first just talk a little bit about the different tests with the main, I guess, cartridges that are used for Rotem, just with a quick overview.

So the main ones that we generally see are XTEM, INTEM, FIBTEM, APTEM and HEPTEM.

And there are some other ones which I won't go into today.

But XTEM basically contains tissue factors.

So this tests the extrinsic pathway of coagulation.

It's similar to the prothrombin type.

The INTEM contains phospholipidic acid and it tests the intrinsic pathway.

So it's similar to an APTT pathway.

The FIV-TEM contains something called cytocalicin D, which is a platelet inhibitor.

So this blocks the platelets contribution to clot formation.

So this assesses fibridogen function and it's used in conjunction with the X-TEM.

And the APS-TEM is the same as the X-TEM, except it also contains aprotitin, which inhibits fibrinolysis.

So therefore, when you compare XTEM to APTEM, it allows for the detection of hyperfibrinolysis.

And finally, HEPTEM uses the same cartridge or same test of the INTEM, except it also contains heparinase.

So this neutralizes the heparin effect.

So comparing Intem to Heptem can detect residual heparin effect.

This is particularly important, say, if it's a patient who is on bypass or post-bypass where they have quite a big effect of heparin, which

might be impacting on their coagulation status.