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For decades, platelet concentrates have been a standard transfusion component for the treatment of clotting disorders. They are prepared from the whole blood within 24 hours from collection from voluntary blood donors by means of differential centrifugation of platelet rich plasma (PRP) or by the apheresis and stored at room temperature with a maximum shelf life of 7 days. They are transfused to the patients who suffer from thrombocytopenia or some other platelet disorder in order to sustain the haemostatic function. Freezing platelets is feasible but results in poor recovery, although the platelets retain their clotting functions after thawing. The use of platelets is permanently increasing, due to advanced surgical and other therapies and they are considered vital products in blood banking today (Brecher, 2005). Apart from their clotting functions, platelets have been shown to possess some other evolutionary highly conserved biological functions, such as immune defence, tissue forming and regeneration. These properties are now clinically used by the virtue of platelet gel preparations. Technically, the clinical precursor of platelet gel has been fibrin glue that was composed of two separate solutions fibrinogen and thrombin. When mixed together, these agents were similar to the last stages of the clotting cascade in forming a fibrin clot. Fibrinogen has been obtained from pooled allogeneic single-donor plasma units and from the autologous blood of the patients and has been usually isolated by the process of cryoprecipitation. The additional thrombin component has been generally derived from commercial bovine sources. Some investigators have even added calcium chloride and/or antifibrinolytics (i.e., aminocaproic acid, aprotinin) to their preparations in order to enhance the clot formation. Although fibrin glue has been used in a variety of surgical procedures for the prevention of bleeding, it has been especially useful in heparinized patients undergoing cardiovascular procedures requiring extracorporeal circulation, as it does not need an intact hemostatic system to be effective. Fibrin glue has also been evaluated in the presealing of woven or knitted Dacron vascular grafts. The major drawback to its use has been attributed to the potential risk of transmitted serological disease from pooled and single-donor blood donors, so the patient's own blood was considered to be the safest preparation to prepare fibrin glue. Overall, fibrin glue is a useful adjunct to other methods to control bleeding in selected surgical patients (Thompson et al., 1988; Lee & Kang, 2011). |
