Best practice & research. Clinical anaesthesiology
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Performing a surgical procedure on a patient undergoing anti-platelet therapy raises a dilemma: is it safer to withdraw the drugs and reduce the haemorrhagic risk, or to maintain them and reduce the risk of myocardial ischaemic events? Based on recent clinical data, this review concludes that the risk of coronary thrombosis on anti-platelet drugs withdrawal is much higher than the risk of surgical bleeding when maintaining them. In secondary prevention, aspirin is a lifelong therapy and should never be stopped. Clopidogrel is mandatory as long as the coronary stents are not fully endothelialized, which takes 6-24 weeks depending on the technique used, but might be required for a longer period.
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Best Pract Res Clin Anaesthesiol · Jun 2007
ReviewAllogeneic red blood cell transfusion: physiology of oxygen transport.
Allogeneic red blood cell (RBC) transfusions have been shown to be associated with considerable risks. While their efficiency in many clinical situations has not been proven, the number of studies finding adverse outcomes in terms of morbidity (e.g. postoperative infections) and mortality continues to rise. ⋯ Only a thorough knowledge of the physiology and pathophysiology of oxygen transport can be a solid base for meaningful transfusion decisions. Therefore, the goal of this article is to review the basics of oxygen transport and normovolaemic anaemia.
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In clinical practice, the decision to transfuse is linked to the hope of increasing oxygen transport (TO2) to tissues. Physiologic transfusion triggers should progressively replace arbitrary hemoglobin-based transfusion triggers. These 'physiologic' transfusion triggers can be based on signs and symptoms of impaired global oxygenation (lactate, venous O2 saturation [SvO2]) or, even better, of regional tissue oxygenation (electrocardiographic ST-segment, electroencephalographic P300 latency). The SvO2 or its surrogate, the central venous 02 saturation (ScvO2), is a clinical tool which integrates the relationship between whole-body O2 uptake and TO2, and as such can be proposed as a simple physiologic transfusion trigger.
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Best Pract Res Clin Anaesthesiol · Jun 2007
ReviewEstimating the cost of blood: past, present, and future directions.
Understanding the costs associated with blood products requires sophisticated knowledge about transfusion medicine and is attracting the attention of clinical and administrative healthcare sectors worldwide. To improve outcomes, blood usage must be optimized and expenditures controlled so that resources may be channeled toward other diagnostic, therapeutic, and technological initiatives. Estimating blood costs, however, is a complex undertaking, surpassing simple supply versus demand economics. ⋯ Recognizing that historical accounting attempts to determine blood costs have varied in scope, perspective, and methodology, new approaches have been initiated to identify all potential cost elements related to blood and blood product administration. Activities are also under way to tie these elements together in a comprehensive and practical model that will be applicable to all single-donor blood products without regard to practice type (e.g., academic, private, multi- or single-center clinic). These initiatives, their rationale, importance, and future directions are described.
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Inherent risks and increasing costs of allogeneic transfusions underline the socioeconomic relevance of safe and effective alternatives to banked blood. The safety limits of a restrictive transfusion policy are given by a patient's individual tolerance of acute normovolaemic anaemia. latrogenic attempts to increase tolerance of anaemia are helpful in avoiding premature blood transfusions while at the same time maintaining adequate tissue oxygenation. Autologous transfusion techniques include preoperative autologous blood donation (PAD), acute normovolaemic haemodilution (ANH), and intraoperative cell salvage (ICS). ⋯ Currently, some controversy regarding contraindications of ICS needs to be resolved. Artificial oxygen carriers based on perfluorocarbon (PFC) or haemoglobin (haemoglobin-based oxygen carriers, HBOCs) are attractive alternatives to allogeneic red blood cells. Nevertheless, to date no artificial oxygen carrier is available for routine clinical use, and further studies are needed to show the safety and efficacy of these substances.