Question 26

Created on Sun, 05/10/2015 - 23:23
Last updated on Sat, 10/24/2015 - 23:15
Pass rate: 66%
Highest mark: 7.0

Other SAQs in this paper

Other SAQs on this topic

A 50-year-old male patient is admitted to ICU following a laparotomy, splenectomy and partial hepatectomy for intra-abdominal bleeding following a high-speed motor vehicle crash with isolated abdominal trauma. He has had a massive transfusion in theatre. He continues to be fluid responsive with a falling haemoglobin concentration consistent with on-going intraabdominal bleeding.

a) Outline your management of this problem.

The International Normalised Ratio (INR) result is >10 and subsequent history reveals the patient was taking warfarin for recurrent deep vein thromboses.

b) List the steps you would take to correct the INR.

The INR corrects to 2.0 and a thromboelastometry is performed with the resultant graphs (Image A) as shown on page 11. (Graphs from a normal individual, Image B, are included for comparison.)

Image A: the patient

Image B: normal

c) What coagulopathy do the patient’s graphs represent and what therapy is indicated?

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College Answer

a)
Clinical examination:
Haemodynamics, abdominal examination, drain losses, exclude other sources of bleeding,
temperature, urine output.
Investigations:
 Ensure blood cross-matched and available
 FBC and Coagulation tests: aPTT, PR, Platelet count, D-Dimers, TEG, Fibrinogen
 ABG
 CXR
Resuscitation:
 Volume replacement
 Transfusion of blood products
 Correction of electrolyte associated with massive transfusion; e.g. hypcalcaemia
 Prevention and treatment of hypothermia
May consider haematology input and activation of a massive transfusion protocol or similar.
Discuss with the surgical team re returning to theatre.
The INR result is >10 and subsequent history reveals the patient was taking warfarin for recurrent
DVTs

b)
Prothrombin Complex concentrate dose 25-50units/kg
Vitamin K 10-20mg
Fresh frozen plasma if ongoing bleeding.(contains Factor VII which is not in PCC)

c)
Thrombocytopaenia / Platelet dysfunction
Platelet therapy +/- cryoprecipitate
Consider DDAVP

Discussion

c) The ROTEM interpretation aspect of this question killed the mood for a lot of people in this exam. The college did not include their ROTEM images in the paper made public on their site, presumably because they plan to recycle them. However, in various ways people are able to get hold of the old papers. If one looks closely enough, one might discover that the college used this Haemoview powerpoint presentation slide for their "normal" image (go to slide 7) and this Haemoview training document for their example of a ROTEM with poor clot stability. Of course, I could have used the same images, but that would have been lazy (and possibly illegal). Instead, de novo synthesis of ROTEM graphs was performed.

Viscoelastic tests of clotting function (TEG and ROTEM) are discussed in greated detail elsewhere. Also, on the ROTEM data interpretation page there are examples of normal and abnormal ROTEM graphs for a series of coagulopathy scenarios. In order to simplify revision, I reproduce the table of normal variables below:

Test CT CFT alpha-angle MCF A10 LI30 ML
INTEM 100-240 30-110 70-83 50-72 44-66 94-100 <15
EXTEM 38-79 34-159 63-83 50-72 43-65 94-100 <15
HEPTEM 100-240 30-110 70-83 50-72 44-66 94-100 n/a
APTEM 38-79 34-159 63-83 50-72 43-65 n/a n/a
FIBTEM n/a n/a 30-70 9-25 7-23 n/a n/a

To arrive at a sensible interpretation, let us go through the thromboelastometry data in systematic detail:

  • The CT intervals for all four tests are within the normal range, suggesting that the coagulation factors are functioning normally.
  • The CFT for EXTEM INTEM and APTEM is abnormally prolonged, suggesting that there is a problem with clot propagation. This finding is not especially specific, and could be attributed to either low platets, poor platelet function or low fibrinogen.
  • The alpha-angle for EXTEM and APTEM is slightly increased, suggesting that there is normal (or slightly increased) reactivity to Tissue Factor, meaning that the warfarin-induced coagulopathy has been well reversed. The INTEM alpha-angle is normal. In short, the initiation of clotting is satisfactory.
  • The A10 and the MCF  for EXTEM INTEM and APTEM are abnormally low, suggesting that clot stability is poor. A low MCF or A10 could be attributed to either low platelets, poor platelet function, low fibrinogen or hyperfibrinolysis. However, given that none of the amplitudes narrow with time, hyperfibrinolysis is clearly not the problem.
  • Looking at the FIBTEM, one can conclude that there is no problem with the fibrinogen. The FIBTEM A10 is quite normal (you would only get worried if it got under 9mm), which suggests that there is plenty of fibrinogen, and that it is functioning normally.  The problem is therefore either low platelet number or poor platelet function.
  • On the basis of this, the college suggests platelet transfusion +/- DDAVP. Cryoprecipitate is also mentioned, presumably because it contains a lot of von Willebrand factor.

References

Practical Haemostasis - best explanation ever.