Best practice & research. Clinical anaesthesiology
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Recombinant activated factor VII (rFVIIa) is a haemostatic agent, which was originally developed for the treatment of haemophilia patients with inhibitors against factor FVIII or FIX. The efficacy of rFVIIa in preventing or stopping life-threatening bleeding for these patients has been demonstrated in several studies. ⋯ Conflicting results have been reported from various studies. Considering the lack of data and potential publication bias associated with case reports, this review summarises the clinical evidence of the efficacy and safety of rFVIIa in the perioperative period.
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Best Pract Res Clin Anaesthesiol · Mar 2010
ReviewPharmacological agents: antifibrinolytics and desmopressin.
This article provides an overview of the scientific evidence regarding the efficacy and safety of antifibrinolytic agents and desmopressin to reduce surgical blood loss. The synthetic derivatives of lysine are the only antifibrinolytics available in clinical practice since the withdrawal of aprotinin. There is evidence that the prophylactic use of lysine analogues is efficacious in reducing perioperative blood loss in cardiac and major orthopaedic surgery. ⋯ Lysine analogues appear to be well tolerated in coronary artery bypass surgery, but less is known regarding their risk-benefit profile in special patient groups. Further studies are needed to elucidate the best compromise between dosing regimen, efficacy and safety in various clinical settings. Desmopressin may reduce excessive bleeding and transfusion requirements in some specific patient populations with acquired platelet dysfunction, but this needs to be validated in future studies.
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Unexplained intra-operative coagulopathies continue to be a diagnostic and therapeutic dilemma. The pathophysiology behind unexplained intra-operative coagulopathies is of great variety and complexity (pre-existing coagulopathies, dilutional coagulopathy, interactions of medications, etc.). We have shown in prospective studies that patients undergoing elective surgery who develop 'unexplained' intra-operative bleeding have significantly less F. ⋯ At least one proof-of-principle landmark study suggests that such patients benefit from treatment with F. XIII early intra-operatively. This new concept helps to explain the pathophysiology behind unexplained intra-operative coagulopathies and thus allows for corresponding treatment strategies.
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Perioperative coagulation monitoring is the rational diagnostic basis for pro- and anti-thrombotic interventions in patients undergoing emergency and elective surgery. The main goal of perioperative monitoring of haemostasis is to increase safety of patients undergoing surgical procedures. Currently, there is a change in paradigm with (1) increasing implementation of evidence-based approach to preoperative patient evaluation with laboratory coagulation testing secondary to the results of the standardised bleeding history and (2) awareness of the limitations of routine coagulation tests to guide coagulation management in massive bleeding. ⋯ This innovative methodology triggers a trend towards an 'early goal-directed coagulation management' focussing on potent coagulation factor concentrates. Practicability, cost-effectiveness, safety and--above all--growing scientific evidence support this concept, and lively discussions among anaesthesiologists and various medical disciplines may help to refine it. The present review focusses on the following key issues of perioperative coagulation monitoring: standardised bleeding history, routine coagulation testing, visco-elastic point-of-care coagulation testing, heparin monitoring, and platelet function testing.
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Perioperative coagulopathy impacts on patient outcome by influencing final blood loss and transfusion requirements. The recognition of pre-existing disturbances and the basic understanding of the principles of and dynamic changes of haemostasis during surgery are pre-conditions for safe patient management. The newly developed cellular model of coagulation facilitates the understanding of coagulation, thereby underscoring the importance of the tissue factor-bearing cell and the activated platelet. ⋯ Recent data from studies using viscoelastic coagulation studies confirm the central role of fibrinogen in stable clot formation and provide essential knowledge about its changes during blood loss and fluid administration. Besides early decrease in clot firmness during mild-to-moderate dilution, profound dilution results in a critical decrease in thrombin generation as well as a reduction in numbers and function of platelets. Although our knowledge of perioperative coagulopathy has dramatically increased over the past few years, several questions such as critical thresholds for fibrinogen, platelets, impact of FXIII and TAFI remain unanswered and need to be investigated further.