Thromboelastography

So the two most common ones are TAG thromboelastogram and Rotem, which stands for rotational something.

But yeah, Teg and Rotem are the two most common viscoelastic testing.

We won't belabor what that is in this episode.

Just check out the episode we have dedicated to that.

But these are much better ways to test the actual coagulation cascade than just sending something like an INR.

Remember, cirrhotics are often deficient in fibrinogen.

So certainly check the fibrinogen if you're not going to do a Teg or Rotem because this is something that we commonly will see low in patients with cirrhosis.

Excuse us, I had to wet the whistle.

In this article, both TAG and Rotem will be reviewed with attention to their clinical uses in the initial resuscitation of the severely injured patient.

a systematic search was undertaken to find peer-reviewed literature describing TEG and Rotem employed for resuscitation of trauma patients.

Patent descriptions, animal studies, non-clinical in vitro, and elective surgical studies were excluded.

Only full-text articles available in the English language were reviewed.

Conventional coagulation tests also take time.

As an example, a multicenter prospective study including actively bleeding patients during major surgical procedures reported a median turnaround time of 88 minutes with a range that extended up to 235 minutes.

Viscoelastic testing, which includes TEG and BRTM, have been shown to identify trauma-induced coagulopathy with increased sensitivity and decreased time to interpretation compared to conventional coagulation tests.

In a large prospective cohort, rapid TEG predicted substantial bleeding and red blood cell transfusion requirements better than PT or PTT.

Later, we saw the development of D-dimer, that is more of a nonspecific marker for DAC, and so on.

Now, the one test that try to look at that process as a whole is the TEG, the thromboelastography.

Now, I must admit that I had to do some reading to prepare for this podcast, and I always thought that TEG is relatively new, because I don't remember studying about it in med school.

But in fact, it was introduced in 1948. and it wasn't really adopted until the 1990s, and only then people have started kind of paying attention to it more and trying to understand the coagulation process as a whole.

Now, the way TEG works, pretty nice idea.

You take a cup and you have a pin and you throw in the blood, whole blood into it, and the cup spins or rotates a little bit.

And then naturally the clot forms around the pill.

I will say more of our tertiary centers tend to have it, um, the nicer hospitals, but the majority of obstetric care is in community facilities and many don't have it, but I do think it should be standard.

And so I would love for you to talk about, first of all, do you have a preference between TEG and Rotem? And just tell me your thoughts on it and how we should best be using it.

Okay.

One thing we haven't discussed is thromboelastography in maternal hemorrhage.

Usually a trigger is about 500 mLs of chest tube output in a single hour or more than 200 per hour that just keeps going.

Now, before you blame the surgeon for anything related to bleeding, make sure that your heparin is fully reversed, the patient is warm, and then you're going to use your VSCO elastic testing like Teg or Rotem to guide the types of products that you're going to give.

I had seen a case one time done by a resident who didn't realize that all the stopcocks were off to the patient and on to the floor.

So all the protamine that was given went to the floor and not to the patient.

Unless there is ongoing ischemia and higher targets are not proven to help, we keep platelets above roughly fifty thousand if bleeding and lower thresholds otherwise, and fibrinogen above about one point five grams per liter.

Viscoelastic testing, ROTEM or TEG, helps us give the right blood product rather than everything at once.

And we monitor for he-mo-lysis daily, plasma-free hemoglobin, LDH, bilirubin, and urine color.

Rising plasma-free hemoglobin suggests pump thrombus, oxygenator thrombus, excessive negative drainage pressure, or cannula malposition, and may require changing parts of the circuit.

Interventional radiology for uterine artery embolization, balloon tamponade, compression sutures, or even hysterectomy may be needed.

At the same time, resuscitation follows a massive transfusion protocol with red cells plasma and platelets guided by laboratory results and ideally point of care viscoelastic tests such as Rotem or TEG, which give rapid information about clot strength and fibrinogen.

Fibrinogen replacement with cryoprecipitate or fibrinogen concentrate is central, aiming to keep fibrinogen above about two grams per liter in ongoing bleeding.

Tranexamic acid, one gram intravenously, should be given as early as possible, ideally within three hours of birth, and a second dose after thirty minutes if bleeding continues.