Along with the usual suspects in the world of emergency medicine / FOAMed podcasts, I’ve tried to start listening to the educational podcasts being generated by those outside of our specialty — the Eastern Association for the Surgery of Trauma, EAST, recently had a great episode of their podcast (“Traumcast”) that featured Dr. Gene Moore, chief of trauma at Denver Health reviewing a single-center RCT comparing the use of viscoelastic coagulation assays to traditional coagulation testing such as INR and PTT in guiding resuscitation of trauma patients.
I went to medical school in Houston and did my clinical rotations at Memorial Hermann, where John Holcomb did his work looking at the use of rotational thromboelastography, including the development of a very robust system for getting TEG results to the trauma team within 15 minutes of the arrival of a patient to the trauma bay. The system they developed also provided automated guidance for the administration of specific blood products based off of the TEG assay, and is described in the second article linked below from Blood: How I treat patients with massive hemorrhage, on which Dr. Holcomb is the coordinating author.
I felt like this made a ton of sense — in the often coagulopathic trauma patient, we have shown over and over again that saline is not the resuscitative fluid of choice, and have more recently demonstrated in large, prospective, pragmatically-designed trials the superiority of using more physiologic (or “balanced”, as many surgeons refer to them) protocols for transfusing bleeding patients. Why not use more dynamic information to help inform the choice of which product goes first to fix the specifically broken link in the cascade of coagulation, as these viscoelastic testing assays seem to offer?
In this study, patients requiring massive transfusion activation were randomized in a block fashion to either have transfusion of blood products guided by TEG or by traditional coagulation assays. MTP activation was based on the Resuscitation Outcome Consortium criteria: SBP <70 mm Hg or SBP 70–90 mm Hg with heart rate > 108 beats/min, in addition to any of the following injury patterns: penetrating torso wound, unstable pelvic fracture, or FAST suspicious of bleeding in more than one region.
One hundred eleven patients were included in an intent-to-treat analysis, evenly split between the groups. Survival in the TEG group was significantly higher than the conventional MTP group (log-rank P = 0.032, Wilcoxon P = 0.027); 20 deaths in the control group (36.4%) compared with 11 in the TEG group (19.6%) (P = 0.049). Most deaths occurred within the first 6 hours from arrival (21.8% CCA group vs 7.1% TEG group) (P = 0.032).
Keeping in mind that TEG is a diagnostic tool rather than a treatment, and the relatively small numbers in this single central study, I don’t know that anyone could definitively say that the use of TEG is responsible for the increased survival seen here, but the results are impressive. Given the additional information conveyed by the TEG or other functional coagulation assays, I think that more broad deployment (including outside the OR, as they have at Memorial Hermann, where the TEG is the first test run off of the trauma activation patient, and where the results– along with a computerized interpretation of the graph with a recommendation for transfusion– print off on a laser printer in the trauma bay automatically) makes a lot of sense.
We should all be learning how to interpret these assays, especially in EM where we are often initiating the massive transfusion and resuscitation of these sick trauma patients (or other exsanguinating patients — I think it stands to reason that functional clotting assays would be much more useful in patients with other kinds of coagulopathy, e.g. liver failure or and sepsis) — I think this is now reaching a broader audience, as just recently Josh Farkas covered the use of TEG in sepsis-induced coagulopathy on PulmCrit and an article in EM Resident magazine covered the basics of TEG. Hopefully as more and more people learn about these technologies, we’ll see wider deployment and utilization, resulting in better care and smarter transfusion strategies.