Best practice & research. Clinical anaesthesiology
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Best Pract Res Clin Anaesthesiol · Mar 2010
ReviewPlatelet transfusions: the science behind safety, risks and appropriate applications.
Platelets are active metabolising cells that are evolved for the tasks of haemostasis, inflammatory reactions and wound healing. When platelet products are stored in the blood bank a complex series of changes occur, leading to partial activation, up-regulation of inflammatory mediators, cellular morphology changes, loss of cell membrane lipids and micro-particle formation, as well as apoptosis. The resultant coagulation transfusion product has a number of potential expected side effects including fever, alloimmunisation, sepsis, thrombosis and transfusion-related acute lung injury. ⋯ However, outcome data (controversial) have shown in some populations that platelet transfusions are associated with worse patient outcomes. Such associations may be due to the biologic changes that have occurred during storage, lack of HLA matching as well as other causes or it could be a mismatch of the platelet products to patient's needs (over-use). Platelets are administered in the surgical arena often due to 'clinical judgement', which errs on the side of, perhaps, too frequent use.
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As the life expectancy of our Western population progressively increases, so does the prevalence of cardiovascular disease and thus the use of antithrombotic drugs. The use of central neuraxial anaesthesia techniques in patients treated with these drugs is a major clinical problem as the presence of an impaired coagulation has been found to be the most important risk factor contributing to the formation of a spinal haematoma. The growing number of case reports of spinal haematoma has led many national societies of anaesthetists to come up with guidelines. This article presents an overview of current guidelines on the use of regional anaesthetic techniques in patients treated with various anticoagulants and also describes a possible strategy to deal with new antithrombotic drugs that have recently been introduced in some countries or will be shortly in others.
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Interruption or maintenance of anti-platelet agents (APAs) during surgical or invasive procedures is associated with an increase in cardiovascular or haemorrhagic complications, respectively. The pharmacology and indications of aspirin, clopidogrel and prasugrel are summarised. The utility and risks of interruption, the optimal delay between stent implantation and surgery, the appropriate window of preoperative interruption, the potential usefulness of bridging, the safest delay between the end of surgery and resumption of APA are detailed in this review. Some non-evidence-based suggestions are given to help the physicians in their daily clinical practice.
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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.