Episode 86 — Thromboelastography With Bob Sikorski
Highlights
- The Thrombin Burst
Summary:
We're in this phase where all the factors are being activated prior to us reaching the point where clotting begins or that cleavage of fireburnogen to fireburn begins. In order for that to begin we need thrombin to be activated. We need a thrombin burst when we get to that common part of that pathway right around 10a and what we'll see is we'll see a straight line and then we'll see that line initially begin to separate it splits which is the split point. So the combination of that split point and the initiation of the R actually becomes the R time. When the clot reaches 2 millimeters in thickness that's the R time from the initiation through
Transcript:
Speaker 1
We're in this phase where all the factors are being activated prior to us reaching the point where clotting begins or that cleavage of fireburnogen to fireburn begins and in order for that to begin we need thrombin to be activated. We need a thrombin burst when we get to that common part of that pathway right around 10a and what we'll see is we'll see a straight line and then we'll see that line initially begin to separate it splits which is the split point. So the R time is that enzymatic portion and that split point is where it kind of separates. So the combination of that split point and the initiation of the R actually becomes the R time. So when the clot reaches 2 millimeters in thickness that's the R time from the initiation through the split point and when we look at an R times split point ratio that actually that delta gives us the significance of the thrombin burst. So we have the initiation phase to the split point and then when we get 2 millimeters of clotting that becomes the R time. (Time 0:08:30)
- A Tag Tracing Looks Like a Wine Glass on Its Side
Summary:
A tag tracing looks kind of like a wine glass on its side. It's got a, it's got the stem which is a flat line and then it starts to separate as Bob said and goes up until you're you've got an amplitude that is like the width of the open wine glass. And so from that beginning to right after, so you said two millimeters after the split happens, so right after you leave the stem of the wine glass that's gonna be your R-time. Right? Factor function or you could even prolong the R-time basically with hemodilution. That's where it occurs. Now on tag we can also get the thrombin velocity curve
Transcript:
Speaker 1
It is giving you the quality of each of the parts. Right. But more important not just each of the segments but how each of the segments interact. Right absolutely.
Speaker 2
So let's just review that piece. So in everyone if you haven't seen, I mean you can easily Google and get a million of these pictures but a tag tracing looks kind of like a wine glass on its side. It's got a, it's got the stem which is a flat line and then it starts to separate as Bob said and goes up until you're you've got an amplitude that is like the width of the open wine glass that continues on. And so from that beginning to right after, so you said two millimeters after the split happens, so right after you leave the stem of the wine glass that's gonna be your R-time. Correct. And that R-time we think of as being an indicator of factor function, right?
Speaker 1
Factor function or you could even prolong the R-time basically with hemodilution. Right. And so the key point of that that split point to that R-time is an indicator of the the efficacy of that thrombin burst. That's where it occurs. Now on tag we can also get the thrombin velocity curve. (Time 0:12:45)
- Is There a Caveat to the R-Time?
Summary:
From the from the beginning to 20 millimeters. So it's basically the 20 millimeters of clot thickness when it occurs. If it's prolonged you have a decrease if it's shortened you have more robust fiber kinetics. Now there's a caveat there as well you have to look at that shape of the tracing and the actual values because of someone bumps the table while this this tag is starting to run in the R-timeIt'll actually cause a split point. The tag doesn't know the difference between somebody bumping and someone not. so it'll measure the split point from there and miscalculate your alpha angle.
Transcript:
Speaker 2
And I think this is a piece a lot of people don't know about is they know the R-time. They don't realize is it the other piece of information there. Not from the beginning to that two millimeter spot but from the split to the two-meter millimeter spot that's that thrombin burst. And then there's also the the additional way to look at it that you mentioned. And then the K is going to be the which you said is going to talk about kind of fibrin kinetics and that's going to be going out to 20 millimeters. And that's from the beginning to 20 millimeters or from the split point to 20 millimeters.
Speaker 1
From the from the beginning to 20 millimeters. So it's basically the 20 millimeters of clot thickness when it occurs. So that time is then measured. If it's prolonged you have a decrease if it's shortened you have more robust fiber kinetics.
Speaker 2
Great. So and then you've got your alpha angle which is going to give you the robustness of the fiber and kinetics and then you've got basically the beginning of that interaction between platelets. How steeply it breaks up it breaks off from that from the blind.
Speaker 1
Now there's a caveat there as well you have to look at that shape of the tracing and the actual values because of someone bumps the table while this this tag is starting to run in the R-time it'll actually cause a split point. The tag doesn't know the difference between somebody bumping and someone not. So it'll measure the split point from there and miscalculate your alpha angle. So there are little things that and that's a little deeper right into the caveats of it. (Time 0:14:22)
- Clot Formation
Summary:
The difference between the fiber engine MA and the platelet MA is actually your fiber engine component to that clot. So we can then tease that out and get more of an in-depth look at our clot formation. We're really right through anti-thrombin 3 where we're inhibiting really the thrombin activation of the platelets basically if we take it back one more step. To the mix is added reptilase reptilase is a thrombin surrogate that's not affected by anti-thrubin 3. By adding replays in factor 13 we get a fiber and fiber engine MA.
Transcript:
Speaker 1
Prior to that we added calcium to counteract the citrate but now we're adding heparin to that that mix to inhibit the platelet component of the clot. So we're really right through anti-thrombin 3 where we're inhibiting really the thrombin activation of the platelets basically if we take it back one more step. However we need to activate and to cleave that fiber engine to the fiber. So to the mix is added reptilase reptilase is a thrombin surrogate that's not affected by anti-thrombin 3. So by adding replays in factor 13 we get a fiber and fiber engine MA. So the difference between the fiber engine MA and the platelet MA is actually your fiber engine component to that clot. So we can then tease that out and get more of an in-depth look at our clot formation.
Speaker 2
Great so that's really interesting. So let's say your MA your regular MA is low is narrow then you do a functional fiber engine and if your fiber engine MA is normal then now you know it's the platelets that are probably. Usually you'll see your fiber kinetics are normal as well. Right okay and so that's one way to do the function fiber engine or as you said before if your K is low your alpha angle is low then that would point more toward fiber engine as the problem rather than your fiber kinetics correct. (Time 0:18:04)
- Fiber Kinolysis
Summary:
If it starts narrowing down to another stem that is abnormal and that indicates clot lysis so what does that tell us. If you see that you would be more inclined to give cryo as you said if you if that's not the issue and it's platelets obviously you're gonna get platelets. Okay so now you talked about this lice 30 or the issue of fiber kinolysis. So normally when a normal tag read out that wine glass will not narrow it will stay but maybe it'll narrow a little bit.
Transcript:
Speaker 2
Interesting okay that's great to know. So if you see that you would be more inclined to give cryo as you said if you if that's not the issue and it's platelets obviously you're gonna get platelets. Okay so now you talked about this lice 30 or the issue of fiber kinolysis so normally when a normal tag read out that wine glass will not narrow it will stay or maybe it'll narrow a little bit it'll stay more or less open as a wine glass. If it doesn't if it starts narrowing down to another stem that is abnormal and that indicates clot lysis so what does that tell us and what do we want to do about it you mentioned tranexamic acid I was certainly taught if you see hyperfibrinal lysis you should give tranexamic acid is that right.
Speaker 1
Good question so I think first of all we need to look at lysis in in two parts here one is do we have primary fiber lysis or is there secondary fiber lysis treatment of either is quite different okay how do we tell so a primary fiber lysis we'll see more of a teardrop a very abrupt (Time 0:19:39)
- Secondary Fiber Lysis
Summary:
A primary fiber lysis we'll see more of a teardrop a very abrupt decrease after that MA. Usually all the other components are shortened as well our alphas a little prolonged, K is a little prolonged and then you'll have that abrupt drop off in secondary fiber lysis.
Transcript:
Speaker 1
Good question so I think first of all we need to look at lysis in in two parts here one is do we have primary fiber lysis or is there secondary fiber lysis treatment of either is quite different okay how do we tell so a primary fiber lysis we'll see more of a teardrop a very abrupt decrease after that MA as we come to the come to the end of that tracing. Usually all the other components are shortened as well our alphas a little prolonged our alphas narrow the K is a little prolonged the MA is maybe low normal and then you'll have that abrupt drop off in secondary fiber lysis like you see in the beginning of the IC we have a very robust curve almost a hyper a really a hypercliable curve and then we'll see the estimated percent lysis really increase so we have a very very high alpha a very short K and the patient will (Time 0:20:32)