BLOOD COMPONENT THERAPY
Dr. G. N. Ramesh, Dr. N. V. Ramaswamy
Traditionally Blood collected in ACD or CPD and stored at 4oc has a shelf life of 3-4 weeks. At this condition platelets and coagulation factors are substantially reduced. Only 10% of patients require whole blood. The use of whole blood must be restricted to cases with massive haemorrhage, DIC or exchange transfusion.
Packed Cells: This is the choice when trasfusion is required to increase the oxygen carrying capacity. Any surgical procedures which require 2-3 units of whole blood can be managed successfully with packed cells and crystalloids solutions.
Platelet Concentrate: One unit of platelet concentrate from a unit of whole blood contains 7x10 10. The infusion of one unit of random donor platelet should result in an increase in the platelet count of 10,000/m2 in a recepient. The increment may be below expected values if patient has antiplatelet antibodies, splenomegales, active haemorrhages fever or DIC. Thrombocytopenia with active bleeding is the most common indication for platelet transfusion platelet also indicated in patient with haemorrhage from congenital or acquired platelet dysfunction. In patients with ITP, platelets are useful only in actively bleeding, or is being prepared for a surgical procedure. Platelet count above 60,000/m3 is safe for any surgical procedure.
One unit platelet aphresis contains 3x10" platelets and is use ful to reduce alloimmunisation. Platelets are stored it 20-24oc in an agitator and has a shelf life of 5 days. The amount of plasma is 30-50 ml/unit. It is contraindicated in thrombotic thrombocytopenic perpura granulocyte concentrate. It may be useful in sick nutropenic patient (ANC <500/cumm) with proved bacterial sepsis unresponsive to 48 hours of optimal antibiotic therapy. A minimum of 1 x 1010 granulocytes is recognized to produce clinical benefit. Granulocyte transfusions are not common in view of difficulty in obtaining in sufficient quality and complications such as allergic reactions, pulmonary insufficiency, CMV transmission. It may induce dramatic response in septic neonates, in some studies nutropenic.
FFP: contains all coagulation factors and albumin and is useful in multiple coagulation factor deficiencies, DIC with bleeding or acute warfar in withdrawals. It is also the product of choice in TTP or HUS. It is wasteful to use for nutritional support, Hypoalbuminomia or volume replacement.
Cryoprecipitate: It contains factors VIII, VWF, Fibronectin, Fibrinogen, XIII. As like FFP, it is stored at . 20oc or below with shelf life of 1 year. Useful in Hemophilia A, VWF disease, Factor XIII def, fibrinogen replacement, Fibronectin is useful in burns, sepsis, multiple trauma where deficiency results in impaired phagocytosis. Bleeding tendency of uremia can also be corrected by the use of cryo when they are bleeding or undergoing surgery.
Cryo supernatant: Siphoned off plasma from the precipitate forms at 4 oC is called cryosupernatant. If contains FII, F VII, FIX, FX albumin and useful in Liverdisease, warfarin reversal, albumin replacement (when commercial preparation not available) Blood Components can be further purified into individual proteins by chromatography and other techniques but these need to be done on an industrial scale and are not possible in blood banks. Examples are intravenous immunoglobulins, hyperimmune Immunoglobulin, Commercial Albumin preparations, Factor concentrates etc.
Conclusion: Component therapy is effective and is the best way to optimize the use of blood Transfusion medicine in India can improve only it blood banks start producing components and clinicians learn how to use these components correctly thus fully utilizing the available blood.