Thrombelastography and rotational thromboelastometry early amplitudes in 182 trauma patients with clinical suspicion of severe injury.

BACKGROUND: Viscoelastic hemostatic assays may provide means for earlier detection of trauma-induced coagulopathy (TIC).

METHODS: This is a prospective observational study of 182 trauma patients admitted to a Level 1 trauma center. Clinical data, thrombelastography (TEG), and rotational thromboelastometry (ROTEM) parameters were recorded upon arrival. Citrated kaolin (CK), rapid TEG (rTEG), and functional fibrinogen curves were extracted, and early amplitudes A5 and A10 were registered. Patients were stratified according to international normalized ratio of 1.2 or less and international normalized ratio greater than 1.2 (TIC patients) as well as transfusion needs (no red blood cells [RBCs], 1-9 RBCs, and ≥10 RBC in 6 hours). Correlations were analyzed by Spearman's correlation.

RESULTS: TIC patients had lower amplitudes than non-TIC patients in ROTEM/TEG as follows: EXTEM, INTEM, and FIBTEM: A5, A10, and maximum clot firmness (MCF); rTEG: A10; CK: maximum amplitude (MA); and functional fibrinogen: A5, A10, and MA (p < 0.05). Furthermore, A5 and A10 had a strong correlation with MA/MCF (ρ > 0.7 and p < 0.01). The A10 amplitudes were significantly lower in patients transfused with 10 or more units of RBC compared with nontransfused patients (p < 0.02). Fibrinogen concentration and platelet count had moderate correlation with A10 compared with A5 and MA/MCF (0.3 < ρ < 0.7 and p < 0.01). Time (median [interquartile range], in minutes) to obtain a reading was faster for A10 than MA/MCF (p < 0.001) (CK, 16 [15-17] vs. 27 [25-30]; rTEG, 11 [11-11] vs. 18 [17-20]; EXTEM, 11 [11-11] vs. 29 [26-31]; and INTEM 13[12-13] vs. 25 [22-29]).

CONCLUSION: Early amplitudes were lower in TIC patients, had significant correlations with MA/MCF, and differentiated between nontransfused and patients receiving one to nine RBC units or 10 or more RBC units within 6 hours. A10's superior correlation with platelet count and fibrinogen concentration suggests that A10 reflects a more dynamic part of the hemostatic process rather than MA/MCF. Early amplitudes may translate into earlier goal-directed transfusion therapy and may allow refinement of existing transfusion algorithms.

LEVEL OF EVIDENCE: Prognostic and diagnostic study, level III.