Hamostaseologie
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The severe impairment of the microcirculation plays a substantial role in the pathogenesis of severe sepsis and septic shock, and leads to multiple organ failure and death. Therapeutic strategies to resuscitate the microcirculatory blood flow and to improve the functional capillar density are therefore essential to surmount the microcirculatory pathology and to avoid tissue hypoxia. ⋯ Dobutamine is the first choice to improve cardiac output and to overcome myocardial depression in septic shock whereas phosphodiesterase-III-inhibitors and levosimendane are still experimental options. Furthermore selective inhibitors of iNOS, nitroglycerol, as well as vasopressin have to be investigated relating to their specific effects on the microcirculation and their influence on survival in seevere sepsis and septic shock.
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Unexplained intraoperative coagulopathies continue to be a diagnostic and therapeutic dilemma. The pathophysiology behind unexplained intraoperative coagulopathies is of great variety and complexity (preexisting coagulopathies, dilutional coagulopathy, interactions of medications etc.). We have shown in prospective studies that patients undergoing elective surgery who develop "unexplained" intraoperative coagulopathies have significantly less FXIII per unit thrombin available at any point in time (i.e. already preoperatively) than patients without such coagulopathies. ⋯ Patients undergoing elective surgery, without clinically obvious coagulopathy but increased preoperative fibrin monomer concentration (as a marker of decreased crosslinking capacity) are at risk for increased intraoperative blood loss. This new concept helps to explain the pathophysiology behind unexplained intraoperative coagulopathies and thus allows for corresponding treatment strategies. Further clinical studies for early detection and interventions in patients with such coagulopathies are necessary.
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Thrombelastometry/-graphy provides information about clot strength and stability. Modified thrombelastometry/-graphy improved standardisation and diagnostic information using this system. Heparinase modified thrombelastometry/-graphy allows estimation of heparin. ⋯ Glanzmann. The correlation between coagulation time in thrombelastometry/-graphy (CT/r-value) to conventional coagulation may be low because of different activators used. The introduction of rotationthrombelastometry (ROTEM) provides a stable system suitable for bedside-monitoring.
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Guidelines of official societies for diagnosis and therapy of intraoperatively occurring hypocoagulability rely mainly on data of patients receiving whole blood transfusions. They recommend--provided that laboratory evaluation shows deficiency (values>1.5 fold normal)--administration of fresh frozen plasma, cryoprecipitate and platelet concentrates (platelet count<50,000 or <100,000/microl). This article describes the pathogenesis of coagulopathy in the light of the special intraoperative setting, emphasizes recent changes of blood component preparation, transfusion triggers, effects of volume therapy and challenges standard laboratory assays as reliable guide for intraoperative hemostatic therapy. The role of thrombelastographic monitoring is discussed as well as an alternative strategy to compensate deficiencies by the use of coagulation factor concentrates instead of or in addition to transfusion of FFP, a new concept which is illustrated by the presentation of an actual case report.
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In trauma associated coagulopathy, the initial treatment consists of hypothermia and acidosis have to be treated aggressively. Already in in the emergency room, fibrinogen deficiency can be detected frequently, in addition, colloids interfere with fibrin polymerisation. Under these aspects, the early administration of fibrinogen seems to be justified. ⋯ The potential of using haemostatic agents like antifibrinolytics and DDAVP for this indication is only supported by few studies, although in individual cases it may be very helpful. The administration of recombinant FVIIa could not achieve sustainable amelioration of the outcome of trauma patients in a randomised controlled trial. Raising inhibitors of coagulation (antithrombin) simultaneously to antihaemorragic therapy is being discussed, but seems not reasonable in the acute phase of a life-threatening haemorrage.