Trauma is the leading cause of death in children. Researchers, starting with Trunkey et
al., have described three general time points of mortality after trauma - in the field,
early secondary to hemorrhage and late due to infectious complications. Early mortality
after trauma is specifically linked to hemorrhage. Trauma-induced coagulopathy is a
multifactorial phenomenon present after trauma in both children and adults that can
worsen hemorrhage and ultimately lead to increased mortality. Classical laboratory
measurements of the coagulation pathway (PT, PTT, INR, fibrinogen, platelet count) have
shown derangement after trauma and are correlated with mortality. However, these
traditional tests of coagulation function take time to run as they are drawn and sent to
a laboratory for evaluation and therefore provide a delayed snapshot of a potentially
evolving coagulopathy scenario. Adult trauma centers have increasingly incorporated
viscoelastic measures of the coagulation cascade to evaluate for and subsequently treat
trauma-induced coagulopathy. One such test is thromboelastography (TEG) which is a whole
blood assay that assesses functional clot kinetics and stability. It provides information
on how various hemostatic factors, including coagulation factors, platelets, and
fibrinogen, contribute to the clot. A 2016 randomized-controlled trial in adult trauma
patients who met criteria for the institutions massive transfusion protocol were
randomized to transfusion guided by TEG or by conventional measure of coagulopathy. The
authors found increased survival in the TEG group as well as less transfusion of
platelets and fresh frozen plasma.
TEG assesses the clot rate, clot strength, and clot stability, which then assists the
clinician in choosing appropriate blood component therapy. The American College of
Surgeons Trauma Quality Improvement Program recommends the use of thromboelastography
when patients are at risk for trauma-induced coagulopathy. Visicoeslastic evaluation of
the coagulation pathway has become the standard of care in adult trauma patients to
provide information on a patient's coagulation status, particularly when the patient is
requiring multiple blood products. This allows the physician to deliver a targeted
hemostatic resuscitation appropriate for the patient needs in real-time. This can result
in a decrease of blood products and quicker reversal of the trauma induced coagulopathy.
Riley Hospital for Children at IU Health has a TEG 5000 machine (Haemonetics Corp.) which
performs the coagulation tests needed to help guide the resuscitation of a critical
trauma patient. While an improvement over previous tests (such as INR, platelet count,
PTT), the TEG 5000 still takes 45-60 minutes to get the results needed to guide
fluid/blood resuscitation, making the results outdated as the patient has potentially
received multiple units of blood products and/or had additional bleeding during that
time. The TEG 5000 machine also has very specific environmental, and preparation needs
(i.e. flat surface which is not bumped; controlled pipetting (dropping) of blood products
into machine as well as mixing of reagents) that is very difficult to do in a busy trauma
bay/emergency department with a critical patient.
The TEG 6s assays are performed in a microfluidic cartridge which only requires a small
amount of a patient's blood be transferred to the cartridge for analysis. The vibration
frequency of the blood meniscus at which resonance occurs is used to create a clot
dynamics tracing. The sample is drawn automatically into the testing chambers rather than
requiring manual pipetting, leading to less user variability. This simpler operation
provides results in 15-20 minutes, making the test more clinically useful in guiding
transfusion therapy during active bleeding.
TEG 6s and TEG 5000 have been evaluated in adult patients with good agreement between the
modalities. More specifically, the TEG 6s has been validated in adult trauma patients.
However, few pediatric studies exist.