Thromboelastometric (ROTEM) findings in patients suffering from isolated severe traumatic brain injury

Severe traumatic brain injury (sTBI) is often accompanied by coagulopathy and an increased risk of bleeding. To identify and successfully treat bleeding disorders associated with sTBI, rapid assessment of coagulation status is crucial. This retrospective study was designed to assess the potential role of whole-blood thromboelastometry (ROTEM(®), Tem International, Munich, Germany) in patients with isolated sTBI (abbreviated injury scale [AIS](head) ≥3 and AIS(extracranial) <3). Blood samples were obtained immediately following admission to the emergency room of the Trauma Centre Salzburg in Austria. ROTEM analysis (EXTEM, INTEM, and FIBTEM tests) and standard laboratory coagulation tests (prothrombin time index [PTI, percentage of normal prothrombin time], activated partial thromboplastin time [aPTT], fibrinogen concentration, and platelet count) were compared between survivors and non-survivors. Out of 88 patients with sTBI enrolled in the study, 66 survived and 22 died. PTI, fibrinogen, and platelet count were significantly higher in survivors (p<0.005). Accordingly, aPTT was shorter in this group (p<0.0001). ROTEM analysis revealed shorter clotting times in extrinsically activated thromboelastometric test (EXTEM) and intrinsically activated thromboelastometric test (INTEM) (p<0.001), shorter clot formation times in EXTEM and INTEM (p<0.0001), and higher maximum clot firmness in EXTEM, INTEM, and FIBTEM (p<0.01) in survivors compared with non-survivors. Logistic regression analysis revealed extrinsically activated thromboelastometric test with cytochalasin D (FIBTEM) MCF and aPTT to have the best predictive value for mortality. According to the degree of coagulopathy, non-survivors received more RBC (p=0.016), fibrinogen concentrate (p=0.01), and prothrombin complex concentrate (p<0.001) within 24 h of arrival in the emergency room. ROTEM testing appeared to offer an early signal of severe life-threatening sTBI. Further studies are warranted to confirm these results and to investigate the role of ROTEM in guiding coagulation therapy.

Platelet function following trauma. A multiple electrode aggregometry study

Platelets play a central role in coagulation. Currently, information on platelet function following trauma is limited. We performed a retrospective analysis of patients admitted to the emergency room (ER) at the AUVA Trauma Centre, Salzburg, after sustaining traumatic injury. Immediately after admission to the ER, blood was drawn for blood cell counts, standard coagulation tests, and platelet function testing. Platelet function was assessed by multiplate electrode aggregometry (MEA) using adenosine diphosphate (ADPtest), collagen (COLtest) and thrombin receptor activating peptide-6 (TRAPtest) as activators. The thromboelastometric platelet component, measuring the contribution of platelets to the elasticity of the whole-blood clot, was assessed using the ROTEM device. The study included 163 patients, 79.7% were male, and the median age was 43 years. The median injury severity score was 18. Twenty patients (12.3%) died. Median platelet count was significantly lower among non-survivors than survivors (181,000/μl vs. 212,000/μl; p=0.01). Although platelet function defects were relatively minor, significant differences between survivors and non-survivors were observed in the ADPtest (94 vs. 79 U; p=0.0019), TRAPtest (136 vs. 115 U; p<0.0001), and platelet component (134 vs.103 MCEEXTEM - MCEFIBTEM; p=0.0012). Aggregometry values below the normal range for ADPtest and TRAPtest were significantly more frequent in non-survivors than in survivors (p=0.0017 and p=0.0002, respectively). Minor decreases in platelet function upon admission to the ER were a sign of coagulopathy accompanying increased mortality in patients with trauma. Further studies are warranted to confirm these results and investigate the role of platelet function in trauma haemostatic management.