Admission Rapid Thrombelastography Can Replace Conventional Coagulation Tests in the Emergency Department

Abstract

Injury and shock lead to alterations in conventional coagulation tests (CCTs). Recently, rapid thrombelastography (r-TEG) has become recognized as a comprehensive assessment of coagulation abnormalities. We have previously shown that admission r-TEG results are available faster than CCTs and predict pulmonary embolism. We hypothesized that r-TEGs more reliably predict blood component transfusion than CCTs. Consecutive patients admitted between September 2009 and February 2011 who met the highest-level trauma activations were included. All had admission r-TEG and CCTs. We correlated r-TEG values [activated clotting time (ACT), r, k, α, maximal amplitude (MA), LY30] with their corresponding CCTs [prothrombin time (PT)/activated partial thromboplastin time (aPTT), international normalized ratio (INR), platelet count and fibrinogen] for transfusion requirements. Charges were calculated for each test. Demographics, vital signs, and injury severity were recorded. We studied 1974 major trauma activations. The median injury severity score was 17 [interquartile range 9-26]; 25% were in shock; 28% were transfused; and 6% died within 24 hours. Overall, r-TEG correlated with CCTs. When controlling for age, injury mechanism, weighted-Revised Trauma Score, base excess and hemoglobin, ACT-predicted red blood cell (RBC) transfusion, and the α-angle predicted massive RBC transfusion better than PT/aPTT or INR (P < 0.001). The α-angle was superior to fibrinogen for predicting plasma transfusion (P < 0.001); MA was superior to platelet count for predicting platelet transfusion (P < 0.001); and LY-30 (rate of amplitude reduction 30 minutes after the MA is reached) documented fibrinolysis. These correlations improved for transfused, shocked or head injured patients. The charge for r-TEG ($317) was similar to the 5 CCTs ($286). The r-TEG data was clinically superior to results from 5 CCTs. In addition, r-TEG identified patients with an increased risk of early RBC, plasma and platelet transfusions, and fibrinolysis. Admission CCTs can be replaced with r-TEG.