Seminars in thrombosis and hemostasis
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Semin. Thromb. Hemost. · Feb 2015
ReviewVenous thromboembolism prophylaxis in critically ill patients.
Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is recognized as a common complication in critically ill patients. Risk factors including critical illness, mechanical ventilation, sedative medications, and central venous catheter insertion are major contributing factors to the high risk of VTE. Because of their impaired cardiopulmonary reserve, PE arising from thrombosis in the deep veins of the calf that propagates proximally is poorly tolerated by critically ill patients. ⋯ As a result, over the past decades, VTE prophylaxis had become a standard of preventive measure in the intensive care unit (ICU). In clinical practice, the rate of VTE prophylaxis varies and may be inadequate in some centers. A perception of a high bleeding risk in critically ill patients is a major concern for most physicians that may lead to inadequate prophylaxis.
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Cardiac surgery with cardiopulmonary bypass determines a serious imbalance of the hemostatic system. The clinical pattern is multifactorial, involving patient-related, drug-related, and surgery-related factors. As a result, the patient is prone to both hemorrhagic and thrombotic complications. ⋯ Thromboembolic complications are the other side of the coin, and their prevention is still a matter of debate. Consumption of natural anticoagulants and endothelial disturbance are important mechanisms underlying this condition. Strategies to limit antithrombin (AT) consumption or to correct low postoperative levels of AT are still a matter of discussion.
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Point-of-care (POC) testing in hemostasis has experienced a significant increase in the spectrum of available tests and the number of tests performed. Short turn-around time and observation of rapid changes in test results are facilitated. The quality control process in POC testing must encompass a preanalytic (collection), analytic (measurement), and postanalytic (clinical response) phase. ⋯ In experienced hands the PFA CT and WBA and TEG are recommended combinations. Application of POC testing depends strictly on whether it improves medical care and patient outcome. More POC test systems are in the research pipeline, but only a few will resist the ravages of time.
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Semin. Thromb. Hemost. · Feb 2015
ReviewHemostasis and thrombosis in continuous renal replacement treatment.
During continuous renal replacement therapy, the delicate equilibrium of hemostasis is disturbed. Owing to a complex interaction of critical illness, uremia, use of an extracorporeal circuit and anticoagulation, patients exhibit both hypercoagulability and an increased risk of bleeding. Contact of blood with foreign material initiates coagulation by triggering the contact activation coagulation pathway, the tissue factor-factor VIIa pathway and activation of platelets and monocytes, which adhere to the membrane. ⋯ Its interference with anticoagulation is therefore unreliable during critical illness. Citrate provides regional anticoagulation and increases biocompatibility. It is better tolerated than heparin and confers less bleeding, less transfusion, and longer circuit life.
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Hemostasis and thrombosis in trauma patients consist of physiological hemostasis for wound healing and the pathological reaction of disseminated intravascular coagulation (DIC). Whole body trauma, isolated brain injury, and fat embolism syndrome, if extremely severe, can cause DIC and affect a patient's prognosis. Shock-induced hyperfibrinolysis causes DIC with the fibrinolytic phenotype, contributing to oozing-type severe bleeding. ⋯ Another type of pathological hemostatic change is acute coagulopathy of trauma shock (ACOTS), which gives rise to activated protein C-mediated systemic hypocoagulation, resulting in bleeding. ACOTS occurs only in trauma associated with shock-induced hypoperfusion and there is nothing to suggest DIC in this phenomenon. This review will provide information about the recent advances in hemostasis and thrombosis in trauma and will clarify the pathogeneses of the pathological processes observed in trauma patients.