E xsanguination is responsible for 30% to 40% of trauma-related deaths. 1,2 Most of these fatalities occur in the prehospital setting. According to standard coagulation tests (SCTs), one quarter to one third of trauma patients present with coagulopathy on admission to the emergency department. 3Y5 The presence of coagulopathy increases the risk for poor outcomes, thus resulting in threefold to fourfold higher mortality rates. 3,5 Coagulopathic patients are at risk of exsanguination. It is assumed that up to 20% of these fatalities are potentially preventable by early hemostatic intervention. 6 Therefore, timely and reliable identification of the underlying cause of bleeding is paramount to improve survival.Despite remarkable advances in knowledge, the etiology of trauma-induced coagulopathy (TIC) is still not fully understood. Recent concepts suggest an ''endogenous'' TIC primarily driven by shock-associated hypoperfusion in combination with tissue trauma, which activates the protein C pathway, resulting in anticoagulation, hypofibrinogenemia, hyperfibrinolysis (HF), and platelet dysfunction. 7,8 In addition, ''exogenous'' factors such as consumption of coagulation proteins, in particular fibrinogen, and dilution of the remaining coagulation factors, accompanied by other potentiating effects, such as acidosis, hypothermia, and electrolyte disturbance, further contribute to TIC. 9 Importantly, TIC is not uniform but varies with pattern of injury and in type during the course of treatment, underscoring the potential importance of point-of-care (POC) testing that can rapidly provide information on an actual individual patient's coagulation status. 10 Conventional plasma-based coagulation testing, such as prothrombin time (PT) or international normalized ratio (INR), and activated partial thromboplastin time (aPTT) fail to fully assess the clotting process. SCTs were designed to evaluate anticoagulation therapy rather than coagulopathy in major trauma. 11 In fact, none of the conventional coagulation tests was developed to predict bleeding or to guide coagulation in the surgical setting. 11Y14 Moreover, a substantial amount of precious time transpires before the results of standard coagulation assessments become available, with a median turnaround time for these tests to be completed at a central laboratory ranging from 78 minutes to 88 minutes. 15,16 Viscoelastic tests (VETs), most commonly thrombelastography (TEG, Haemoscope-Haemonetics, Niles, IL) and rotational thromboelastometry (TEM, Tem Systems Inc., Durham, NC), provide a valuable alternative or an adjunct to SCT in the setting of bleeding in the emergency department. VETs yield rapid, POC assessment of whole-blood coagulation in a variety of conditions in which conventional testing may not be sensitive. 12,15,17,18 Unlike SCT, VETs provide a rapid and dynamic bedside assessment of the initiation and kinetics of clot formation, maximum clot firmness (MCF), and clot breakdown. 12,17,18 VETs can characterize the range of acute coagulopathies present in patient...

BACKGROUND Bleeding is a potential complication after neuraxial and peripheral nerve blocks. The risk is increased in patients on antiplatelet and anticoagulant drugs. This joint guideline from the European Society of Anaesthesiology and Intensive Care and the European Society of Regional Anaesthesia aims to provide an evidence-based set of recommendations and suggestions on how to reduce the risk of antithrombotic drug-induced haematoma formation related to the practice of regional anaesthesia and analgesia. DESIGN A systematic literature search was performed, examining seven drug comparators and 10 types of clinical intervention with the outcome being peripheral and neuraxial haematoma. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for assessing the methodological quality of the included studies and for formulating recommendations. A Delphi process was used to prepare a clinical practice guideline. RESULTS Clinical studies were limited in number and quality and the certainty of evidence was assessed to be GRADE C throughout. Forty clinical practice statements were formulated. Using the Delphi-process, strong consensus (>90% agreement) was achieved in 57.5% of recommendations and consensus (75 to 90% agreement) in 42.5%. DISCUSSION Specific time intervals should be observed concerning the adminstration of antithrombotic drugs both prior to, and after, neuraxial procedures or those peripheral nerve blocks with higher bleeding risk (deep, noncompressible). These time intervals vary according to the type and dose of anticoagulant drugs, renal function and whether a traumatic puncture has occured. Drug measurements may be used to guide certain time intervals, whilst specific reversal for vitamin K antagonists and dabigatran may also influence these. Ultrasound guidance, drug combinations and bleeding risk scores do not modify the time intervals. In peripheral nerve blocks with low bleeding risk (superficial, compressible), these time intervals do not apply. CONCLUSION In patients taking antiplatelet or anticoagulant medications, practitioners must consider the bleeding risk both before and after nerve blockade and during insertion or removal of a catheter. Healthcare teams managing such patients must be aware of the risk and be competent in detecting and managing any possible haematomas.