Objective -To review the current literature in reference to the pathophysiology and diagnostic modalities available for acute traumatic coagulopathy (ATC) in relationship to traumatic hemorrhagic shock. Etiology -Posttraumatic hemorrhage is responsible for one of the leading causes of preventable human deaths worldwide. Acute traumatic coagulopathy is an endogenous hypocoagulable condition that has been observed during the immediate (< 1 hour) posttraumatic period. Phenotypically, ATC manifests as a state of systemic hypocoagulability and hyperfibrinolysis. Although different functional mechanisms have been proposed for causing ATC, it is universally thought to be a manifestation of severe tissue injury, shock-induced hypoperfusion, systemic inflammation, and endothelial damage. Excessive activation of the thrombin-thrombomodulin activated Protein C pathway, catecholamine-induced endothelial damage as well as disseminated intravascular coagulation (DIC) with a fibrinolytic phenotype are all hypotheses that have been proposed in attempts to explain the functional mechanism of ATC. Diagnosis -An accurate and reliable test remains to be validated for ATC. Traditional coagulation assays (activated partial thromboplastin times and prothrombin times) along with platelet count and fibrinogen concentrations have been used more commonly. Viscoelastic tests (thromboelastography and rotational thromboelastometry) are currently being investigated as a more predictive modality for identifying and guiding therapy for ATC. Therapy -Damage control resuscitation and hemostatic resuscitation are gaining favor as the optimal resuscitative strategies for hemorrhagic shock and ATC. Antifibrinolytics may also play a role when hyperfibrinolysis is present. Prognosis -Massive hemorrhage accounts for 30-56% of prehospital posttraumatic deaths in people, with coagulopathic hemorrhage remaining one of the major causes of preventable deaths within the first 24 hours posttrauma. Ten to twenty-five percent of human trauma patients experience ATC, which has been shown to prolong hemorrhage, deter resuscitative efforts, promote sepsis, and increase mortality by at least 4-fold. Prognosis in veterinary patients is not currently known.

Objectives:To systematically examine the evidence for use of a specific protocol (dose, frequency, route) of selected antithrombotic drugs, in comparisons to no therapy or to other antithrombotic therapies, to reduce the risk of complications or improve outcomes in dogs and cats at risk for thrombosis. Design: Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence (LOE) and quality (Good, Fair, or Poor), and development of consensus on conclusions via a Delphi-style survey for application of the concepts to clinical practice. Settings: Academic and referral veterinary medical centers. Results: Databases searched included Medline via PubMed and CAB abstracts. Eight different antithrombotic drugs were investigated using a standardized Patient, Intervention, Comparison, Outcome (PICO) question format both for dogs and cats, including aspirin, clopidogrel, warfarin, unfractionated heparin (UFH), dalteparin, enoxaparin, fondaparinux, and rivaroxaban, generating a total of 16 worksheets. Most studies identified were experimental controlled laboratory studies in companion animals (LOE 3) with only four randomized controlled clinical trials in companion animals (LOE 1). Conclusions:Overall, evidence-based recommendations concerning specific protocols could not be formulated for most antithrombotic drugs evaluated, either because of the wide range of dosage reported (eg, aspirin in dogs) or the lack of evidence in the current literature. However, clopidogrel administration in dogs and cats at risk of arterial thrombosis, notably in cats at risk of cardiogenic thromboembolism, is supported by the literature, and specific protocols were recommended. Comparably, aspirin should not be used as a sole antithrombotic in cats with cardiomyopathy. Using the available safety profile information contained in the literature, the panel reached consensus on suggested dosage schemes for most antithrombotics. Significant knowledge gaps were highlighted, which will hopefully drive novel research.

Due to the lack of current evidence in the veterinary prehospital arena, best practice guidelines were developed as an initial platform. Recommendations were based on a review of pertinent human and available veterinary literature as well as a consensus of the authors' professional opinions. It is anticipated that evidence-based additions will be made in the future.

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Hemorrhage accounts for up to 40% of human trauma-related deaths and remains the leading cause of preventable death in human trauma. The exact proportion of trauma-related deaths due to exsanguinations in veterinary patients remains uncertain. Survivability depends upon achieving rapid definitive hemostasis, early attenuation of posttraumatic coagulopathy, and timely restoration of effective circulating volume. Early institution of damage control resuscitation in severely injured patients with uncontrolled hemorrhage has the ability to curtail posttraumatic coagulopathy and the exacerbation of metabolic acidosis and hypothermia and improve survival until definitive hemostasis is achieved.