BACKGROUND: Early amplitudes in the viscoelastic hemostatic assays, thrombelastography (TEG) and rotation thromboelastometry (ROTEM), provide fast results, which is critical in the resuscitation of bleeding patients. This study investigated associations between TEG early amplitudes and standard TEG variables in a large multicenter cohort of moderately to severely injured trauma patients admitted at three North European Level I Trauma Centers.

METHODS: Prospective observational study of 404 trauma patients with clinical suspicion of severe injury from London, UK, Copenhagen, Denmark and Oslo, Norway. Biochemistry and clinical data including outcome and TEG parameters were recorded upon arrival. Kaolin TEG, Rapid TEG, and TEG functional fibrinogen curves were extracted, and early amplitudes A5 and A10 (amplitude at 5 and 10 minutes) were registered. Patients were stratified according to international normalized ratio of 1.2 or less or greater than 1.2, as well as transfusion requirements (nontransfused, 1-9 red blood cell units and ≥10 red blood cell units in 12 hours).

RESULTS: In total, 404 patients were included, median Injury Severity Score was 13. There were strong positive correlations between A5/A10 and maximum amplitude in all investigated assays. All TEG values except rTEG maximum amplitude and kTEG maximum amplitude correlated significantly with mortality in transfused patients. Time from initiation of assay to A5 and A10 were lowest for rapid TEG and TEG functional fibrinogen compared with kaolin TEG. Rapid TEG A5 reduced time to result with greater than 50% compared with rapid TEG maximum amplitude.

CONCLUSION: We found strong associations between TEG early amplitudes A5/A10 and maximum amplitude in rapid TEG, kaolin TEG, and TEG functional fibrinogen across trauma patients with coagulopathy and massive transfusion requirements. Introducing the use of early amplitudes can reduce time to diagnosis of coagulopathy and may be used in TEG monitoring of trauma patient. Further randomized controlled trials evaluating the role of TEG in guiding hemostatic resuscitation are warranted.

LEVEL OF EVIDENCE: Prognostic study, level III.