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
# Comparison tables
#tables
## Thromboelastography vs traditional coags
| | advantages | disadvantages |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| conventional testing | - widely available<br>- familiar<br>- lower cost | - mostly derived to monitor therapeutic anti-coagulation<br>- often do not measure physiological or pathologically important clotting mechanisms<br>- of limited relevance for assessment of clotting in major haemorrhage, especially in trauma |
| viscoelastic testing | - POC test; usable results in 10 min<br>- more closely reflects in vivo coagulation / more accurate<br>- *goal-directed product resuscitation* <br>- repeat to detect response to treatment<br>- may be helpful for theatre show coagulopathy reversed | - requires close attention to technique and quality control<br>- needs to be processed within 3 minutes for accurate result<br>- poor precision<br>- machine needs multiple recalibrations per day<br>- $80 per use<br>- 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<br>- cheaper than wasting blood products ; conserves blood bank resources<br>- tests fibrinolysis<br>- assess response to treatment<br>- reduced use of blood products | - not as rapid as empirical transfusion<br>- more expensive than coags<br>- requires QI, calibration<br>- poor precision<br>- confusing<br>- non-specific for warfarin and NOACs<br>- no good evidence of superiority |
| fixed ratio [[Massive blood transfusion\|massive transfusion]] | - rapidly available<br>- easily protocolised ; avoid task-focus<br>- cost of products themselves only expense | - debate about PROPER 1:1:1<br>- hard to assess response to treatment<br>- 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
# TEG
![[Pasted image 20240225153823.png]]
# ROTEM
![[Pasted image 20240225153902.png]]
| parameter | interpretation | treatment |
| -------------------------- | ----------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------- |
| 1. clotting time<br>**CT** | - coagulation activation, presence of clotting factor inhibitors (eg heparin)<br>- FIBTEM CT > 300 sec<br>- EXTEM CT > 90 sec | - prolonged → [[FFP]] or [[Prothrombinex]] |
| 2. Amplitude<br>**A5** | - clot *strength* or firmness<br>- affected by fibrin and fibrinogen, plt count, thrombin concentration, haematocrit | - FIBTEM A5 <10mm → [[cryoprecipitate\|Cryo]]<br>- FIBTEM A5 normal but EXTEM A5 <35 → give platelets |
| 3. Lysis<br>**ML %**<br> | hyperfibrinolysis<br>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]]