Page 117 - JSOM Summer 2022

diseases and illnesses have a linked connection between in- TABLE 1 Thromboelastography (TEG) Parameters
flammation and coagulopathy. 41 Variable TEG ROTEM
From start until R value
Endotheliopathy 2 mm baseline (reaction time) Clotting time (CT)
Endotheliopathy is the breakdown of the endothelial glycoc- From 2–20 mm Clot formation time
alyx (EG). The EG is a heterogeneous group of proteoglycan above baseline K value (CFT)
core proteins linked with glycosaminoglycan chains that line Angle of tangent
the luminal side of the vascular endothelium. The EG works Alpha angle (°) Slope at 2 mm
as an anticoagulant due to components such as heparin and Maximum strength Maximal amplitude Maximal clot
chondroitin sulfates. There are three main components that firmness
38
cause the EG disruption and destruction : (1) endothelial Clot lysis (CL) CL 30, CL 60 LY30, LY 60
compromise and paracellular permeability, (2) dysfunctional at minutes
coagulation, and (3) inflammation. Used with permission from: Lancé MD. A general review of major
global coagulation assays: thrombelastography, thrombin generation
test and clot waveform analysis. Thromb J. 2015;13:1.
Acute inflammatory states, such as hemorrhagic shock, dis-
rupt EG function and cause transfer of plasma protein into the
interstitial space. 42,43 Breakdown of the EG leads to increased
permeability. FIGURE 5 TEG versus ROTEM.

Determining Coagulopathy
There are several signs and symptoms that may accompany
ATC, including an injury severity score > 15, a base defi-
cit > 6mmol/L (normal range –2 to +2mmol/L), hypotension
(< 90mmHg), and tachycardia (> 100 beats/min). 10,35,44,45 While
coagulopathy is defined as a PT ratio more than 1.5 times Used with permission from: Cannata G, Mariotti Zani E, Argentiero
®
®
greater than normal, PTT ratio is at least 1.5 times greater than A, et al. TEG and ROTEM traces: Clinical applications of viscoelas-
normal, fibrinogen > 0.8 g/L, coagulation factor levels < 30% tic coagulation monitoring in neonatal intensive care unit. Diagnostics
(Basel). 2021;11(9):1642.
12
9
of normal, and platelet count < 50 × 10 /L . The PT/ interna-
tional normalized ratio (INR) is also widely used on its own. 37 ROTEM = rotational thromboelastometry; TEG = thromboelastometry
Current Treatments
Some find the use of standard lab tests as indicators of coag-
ulopathy troubling because lab tests were not developed to The current approach to treating coagulopathy association
measure coagulation issues associated with trauma. More spe- with trauma and hemorrhagic shock as a whole include hem-
cifically, a platelet count does not account for the functionality orrhage control, pharmacological interventions, and blood
of those platelets and measuring fibrinogen accounts for only transfusions. Any compressible hemorrhage should be con-
one aspect of the coagulation cascade. Moreover, INR and trolled as a priority. Noncompressible torso hemorrhage
PTT were designed to measure coagulation for genetic clotting (NCTH) is more challenging in the prehospital setting without
46
deficiencies and those on anticoagulants. It is becoming a a dominant definitive method for controlling the hemorrhage.
standard to utilize viscoelastic assays of hemostasis (ROTEM Interventions such as resuscitative endovascular balloon oc-
and TEG) for guided trauma resuscitation. clusion of the aorta (REBOA) are technically difficult in the
prehospital setting and have a limited time of balloon inflation

ROTEM measures the kinetics of hemostasis: clotting time before causing ischemia below the balloon. Other treatments,
(CT), alpha angle, clot formation (CF), clot stability, and lysis to include expanding foams and gastroesophageal resuscita-
(LY). Measurements are made in time (seconds) and in ampli- tive occlusion of the aorta (GROA) have not made their way
tude (A) (mm). CT is measured at 2 mm, CF is then measured to clinical application by prehospital providers.
at 20 mm. Clot firmness, as measured in mm, at 5 min is called
A5. Serial measurements using the same method through 60 Tranexamic acid (TXA) remains a primary pharmacological
minutes is AX. The highest amplitude along the curve is the intervention when given within 3 hours of injury. 7,48 TXA is a
maximum clot firmness (MCF). As time continues and the curve lysine analogue that prevents the activation of plasminogen to
begins to decrease in amplitude, it signifies clot lysis or fibrino- plasmin by tPA, which interrupts the normal fibrinolysis. The
lysis. The alpha angle is an important measure in ROTEM: it is results of CRASH-2 demonstrated an overall mortality bene-
the angle of the curve during initial formation and a measure of fit, with mortalities of 14.5% versus 16.0% in the TXA and
49
fibrin polymerization. FIBTEM allows for evaluation and mea- control group, respectively. In the Military Application of
sure of fibrinogen. EXTEM is the equivalent of PT or INR, and Tranexamic Acid in Emergency Trauma Resuscitation (MAT-
INTEM measures the activated intrinsic pathway. 47 TERs I) study, the benefit was greatest in patients receiving
massive transfusion and was independently associated with
50
TEG measure the similar values as ROTEM. Differences in re- survival. However, a 2017 analysis by Howard et al. failed
porting and measurements include: CT is reported as reaction to demonstrate a benefit and showed an increased rate of deep
time (R), clot formation is measured as kinetics (K), the alpha vein thrombosis. They did note the low power of their data
51
angle is the slope between R and K, and clot firmness is reported may have been rationale for failure to demonstrate a survival
as maximum amplitude (MA) (Table 1, Figure 5). The use of benefit. Regardless, the question remains as to whether TXA
TEG and ROTEM are not without caution, as the cutoff values is beneficial without blood transfusion. This is partially sup-
to determine TIC/ATC vary based on the study and institution. 4 ported by the MATTERs II trial, which demonstrated that

Traumatic Coagulopathy: Prehospital Provider Review | 113