TEG, ROTEM, coagulation studies - ACEM Fellowship Notes

see also [[Massive blood transfusion]], [[Coagulopathy]] - [Dunn Coagulation testing](x-devonthink-item://9784DE30-177E-404E-A088-C276A401A7A8) - [Deranged physiology interpetation of abnormal ROTEM data](https://derangedphysiology.com/main/required-reading/haematology-and-oncology/Chapter%201.2.0.1/intepretation-abnormal-rotem-data) - [em docs TEG 5 min primer](https://www.emdocs.net/thromboelastogram-teg-five-minute-primer-emergency-physician/) - [[#ITACTIC 2020]] - good trial not showing much benefit > The TEG section is not very good/ #incomplete and I suggest you skip it. Interpreting it is also very low yield for the exam. # Comparison tables #tables ## Thromboelastography vs traditional coags | | advantages | disadvantages | | -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | conventional testing | - widely available - familiar - lower cost | - mostly derived to monitor therapeutic anti-coagulation - often do not measure physiological or pathologically important clotting mechanisms - of limited relevance for assessment of clotting in major haemorrhage, especially in trauma | | viscoelastic testing | - POC test; usable results in 10 min - more closely reflects in vivo coagulation / more accurate - *goal-directed product resuscitation* - repeat to detect response to treatment - may be helpful for theatre show coagulopathy reversed | - requires close attention to technique and quality control - needs to be processed within 3 minutes for accurate result - poor precision - machine needs multiple recalibrations per day - $80 per use - no good evidence of superiority (Cochrane 2015, [ITACTIC 2020](https://www.thebottomline.org.uk/summaries/icm/itactic/)) ; no evidence of patient-centred outcomes | ## thromboelastography vs empirical massive transfusion | | Advantages | Disadvantages | | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | TEG / ROTEM | - rapid - cheaper than wasting blood products ; conserves blood bank resources - tests fibrinolysis - assess response to treatment - reduced use of blood products | - not as rapid as empirical transfusion - more expensive than coags - requires QI, calibration - poor precision - confusing - non-specific for warfarin and NOACs - no good evidence of superiority | | fixed ratio [[Massive blood transfusion\|massive transfusion]] | - rapidly available - easily protocolised ; avoid task-focus - cost of products themselves only expense | - debate about PROPER 1:1:1 - hard to assess response to treatment - does not account for fibrinolysis (need to give TXA separately) | ## ITACTIC 2020 [ITACTIC 2020 - the bottom line](https://www.thebottomline.org.uk/summaries/icm/itactic/) - In adult trauma patients presenting with signs of haemorrhagic shock, this trial did not show benefit of viscoelastic haemostatic assay augmented protocols when compared to conventional coagulation tests augmented protocols - This is a well done, pragmatic trial set out to try and address an area with limited randomised research however given my reservations above, and some of the trends shown, further studies would be warranted before concluding that VHA has no place in the management of bleeding trauma patients - Examples of further work could include the use of a stepwise sequential protocol, having trauma induced coagulopathy as an inclusion criteria, and the use in TBI # Anticoagulant and coagulation tests table | agent | PT / INR | APTT | thrombin time | | ---------------------------------------------- | --------------- | ------ | --------------- | | [[Warfarin, DOAC, heparin reversal\|warfarin]] | ↑ | n or ↑ | normal | | heparin | up in high dose | ↑ | ↑ or normal | | LMWH | normal | normal | up in high dose | | dabigatran | normal | ↑ | ↑ | | rivaroxaban | variable | normal | normal | | apixaban | ↑ | normal | normal | **Factor VIII** : primarily used in [[Haemophelia|haemophelia A]] **Factor IX** : haemophilia B **Fibrinogen (factor I)** : monitoring: - coagulopathies (eg [[DIC]], [[Snakebite]], etc) - [[Massive blood transfusion|traumatic haemorrhage]] - hepatic synthetic function **Anti Factor Xa** - therapy with LMWH, can be used for rivaroxaban and apixaban # ROTEM ![[Pasted image 20240225153902.png]] | parameter | interpretation | treatment | | -------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- | | 1. clotting time **CT** | - coagulation activation, presence of clotting factor inhibitors (eg heparin) - FIBTEM CT > 300 sec - EXTEM CT > 90 sec | - prolonged → [[FFP]] or [[Prothrombinex]] | | 2. Amplitude **A5** | - clot *strength* or firmness - affected by fibrin and fibrinogen, plt count, thrombin concentration, haematocrit | - FIBTEM A5 <10mm → [[cryoprecipitate\|Cryo]] - FIBTEM A5 normal but EXTEM A5 <35 → give platelets | | 3. Lysis **ML %** | hyperfibrinolysis normal < 15% | > 15% → [[TXA]] | EXTEM similar to PT (tissue factor and extrinsic pathway) FIBTEM isolates fibrinogen function INTEM similar to APTT (intrinsic pathway tested) ![[Pasted image 20240726235316.png]] ![[Pasted image 20240802202452.png|important patterns (LITFL)]] ![[Pasted image 20240802193244.png]] # TEG see: [Trauma ICU - TEG](https://traumaicu.org/teg/) > - The amount of tacit expectation that people are supposed to understand how to read these screens truely eclipses me; the dearth of straightforward explanations of how to pragmatically read a TEG suggests to me that this is not a widely-held skill. > - Perhaps the first misconception to clear up is the fact that there is a TEG 5000 and a TEG 6s. TEG 6s is more important in trauma because it does a better job of measuring *fibrinogen* function. The rest of this guideline refers to TEG 6s > [!warning] Alert > This section on TEG is not particularly good and I suggest you skip it. I wanted to provide a simple explanation, but unfortunately I cannot access the TEG-6 learning modules, and as stated above, the online content on the subject is dubious. Therefore, this section is incomplete. It is published online simply because I don't want exclude other updates to this page on the website. This is what the screen *might* look like for TEG 6s: ![[Pasted image 20260426201559.png]] Note that there is an **A10** column, which is an important column (somewhat like FIBTEM A5 if you know ROTEM). *However* the TEG 6s machine itself might not have this column! it might actually need to be viewed on the computer. ## Concepts Essentially, a drop of citrated blood rotates around a pin and different assay agents affect the stages of clot formation. As coagulation occurs, the clot sticks to the pin, and the magnitude of the pin motion is directly related to the strength of the clot. this get graphed. There are a lot of articles online about interpreting the shape of the graph, but in my practice setting I have never seen this interpreted; everyone just looks at the values. ### Assays Each assay is on a different channel. We tend to focus on different parts of each assay channel depending on what we are measuring. For instance, if we are focusing on fibrinogen, we use the CFF channel, and we only look at the parameter where fibrinogen comes into the picture, eg MA and A10. If we are concerned about clotting initiation, - **CK** -- Citronated Kaolin. Activates clot formation - **CKH** -- Heparinase. Adds enzyme to neutralise heparin. Helps evaluate the inhibitor effects of heparin (eg CK/CRT is low but CKH is normal means heparin was present). - **CRT** -- Citrated RapidTEG. Uses Kaolin and Tissue Factor to Accelerate the Reaction - **CFF** -- Citrated Functional Fibrinogen. Adds something to inhibit platelet activity. By eliminated platelet effect, the new maximum amplitude only represents the effects of *fibrinogen*. This allows differentiation between deficiencies in fibrinogen vs platelets ![[Pasted image 20260426201839.png]] ![[Pasted image 20260426201851.png]] ### Parameters 6 parameters are measured for each assay: 1. **R time** -- *reaction* time phase. time for blood to begin clotting after addition of the clotting activator (CK). reflects latency before initiation of clotting cascade. normally takes 5-10 min to reach 2mm. prolonged in cases of clotting factor deficiency or presence of anticoagulation . can give *FFP* for this if prolonged 2. **K time** -- *kinetical* phase. time for clot to reach certain level of firmness at 20mm. reflects speed of initial clot formation, depends on accumulation on fibrinogen. normal value 1-3 min. prolonged means low *fibrinogen* 3. **alpha angle** -- slope of curve during clot formation during kintetical phase. reflects rate of fibrin cross linking as an indication of strength of clot. normal 50-70 deg, decreased in low fibrinogen. may need **cryo** or fibrinogen 4. **A10** -- amplitude at 10 minutes. clot strength at 10 min, which is faster to obtain than MA 5. **MA** -- maximum amplitude. strength and firmness -- 55-75mm. if decreased, may be thrombocytopenia of *platelet dysfunction* -- may need platelets 6. **LY-30** -- lysis at 30 min -- percentage of clot breakdown at 30 min after max amplitude. ability of clot to resist breakdown. normally 0-8%. if LY-30 increased, may have ↑ fibrinolysis, may need *TXA*. ![[Pasted image 20240225153823.png]] - Time on x axis, amplitude (e.g., clot strength) on the _y_-axis - The values with clinical implications include reaction time (R), α-angle, kinetics (K), maximum amplitude (MA), and lysis at 30 minutes (Ly30), which can be extended to 60 minutes in some patients. - R is the time from the start of the assay to the point where clot strength reaches an amplitude of 2 mm. - K is the time measured from R to the time when amplitude is 20 mm. - The α-angle is generated from the x-axis and a line drawn from R to the point on the curve where K intersects with 20 mm of amplitude. - MA is the highest amplitude reached. - Ly30 is the percent decrease in amplitude 30 minutes after MA - TEG Trauma Panel – (**CK, CRT, CFF**) For trauma or severe bleeding. - TEG Global Hemostasis Panel – (CK, CKH, CRT, CFF) For Cardiac surgery/procedures. Also shows heparin effect. Up to 1IU/mL. - TEG Global Hemostasis Panel -HN Liver/On-pump/ECMO– (CK,CKH, CRTH, CFFH) For Cardiac surgery/procedures or liver transplant. Shows fibrinolysis and reverses high dose heparin in all channels. Up to 5IU/Ml. - TEG Platelet Mapping Panel- (HKH, ActF, ADP, AA) Used if the patient is on anti-platelet drugs or has risk for platelet dysfunction. Pre op bleeding risk assessment tool. | Test | Component | Interpretation | Normal | Value | Tx | | ------------------ | -------------------------------- | ------------------------------------- | ------------- | ------- | --------------------------------- | | CFF(H) (FF A10) | ↓ MA | ↓ Fibrinogen | | ≤15 mm | cryo (or fibrinogen if feisty) | | CFF MA | maximum strength of clot | | 15-32 mm | <15 | | | CRT(H) | ↓ MA | ↓ Platelets / fibrinogen | 52 - 70 mm | < 52 mm | consider platelets | | CK | ↑ R | ↓ coagulation factors / heparin / DTI | 4.6 - 9.1 min | > 8 | FFP | | CKH | RCK > RCKH | Heparin effect | | | | | CK(H) | ↑ LY 30 | hyperfibrinolysis | | > 2.6% | TXA | ![[Pasted image 20260426173028.png]] | parameter | interpretation | treatment | | --------------------- | -------------- | --------- | | 1. CKH:R < CK:R ? | | | # TEG vs ROTEM ![[Pasted image 20260426205314.png]] ![[Pasted image 20260708171330.png]] # FEISTY ![[Pasted image 20260426170938.png]]