Studies on the Frozen Platelet Transfusion

In 1969, the frozen blood center was set up in the Fukuoka-Chuo National Hospital, Since the beginning of the center, 3, 000 units of frozen red cells were transfused for 400 patients until September 30, 1972. And, 140 units of frozen platelets were infused for 15 patients. In this paper a technique of frozen platelets by us was shown.<br>Blood was collected in acid-citrate-dextrose solution in a plastic bag. Platelets were generally separated from fresh whole blood by differential centrifugation in a standard refrigerated centrifuge. The technique is to spin the blood in swinging buckets at 1, 000rpm (280×G) for 15 minutes. After the centrifugation, the supernatant plasma containing the platelets is expressed into another bag. Centrifugation of the plasma in the bag at 3, 000rpm (2, 510×G) for 10 minutes will drive the platelets into a bottom leaving a platelet-poor-supernate. The platelet-poor-plasma is suitable for freezing to provide a source of labile clotting factors. Platelet-concentrates may be prepared by vigorously rubbing the bag. An equal volume of 28% glycerol solution containing 3% mannitol and 0.65% NaCl is added to give a final concentration of 14% glycerol.<br>After the glycerolization, the plastic container is packaged into a cardbord box, which is frozen at -80° to -90°C. When needed, the plastic bag is plunged into water +45°C for thawing. Deglycerolization is accomplished by adding 250ml of 13% sodium citrate. After incubation for 10 minutes at room temperature, the citrate is removed by centrifugation of 3, 000 rpm for 10 minutes at 4°C. Frozen platelets are driven into the bottom of the bag as a white layer. The supernatant containing glycerol is decanted, and the same process is repeated once more, and about 30ml of frozen platelet concentrate remains. The frozen platelets driven into the bottom of the bag should be resuspended by adding a 0.9% saline solution. The original plasma is also used for the resuspension.<br>Figure 1 shows the resuspended frozen-platelet-concentrate observed by phase contrast micros-cope. Figure 2 shows clot retraction of the frozen platelets. Therefore, it is believed that their function is also normally preserved. TEG, bleeding and coagulation time, and PTT of the patient are remarkably improved.<br>One hundred and forty units of frozen platelets were infused in 15 thrombocytopenia patients. Table 1 shows the total numbers of frozen platelet transfusions. The second case had severely complained of haemoptysis from irradiation and anticancer drug therapy, who was infused with 3 units of frozen platelets. His symptomes drammatically subsided and were cured. Figure 3 shows the changes of platelet-counts of the recipients after frozen platelets infusion. The platelet counts remarkablly increased. Iatrogenic thrombocytopenia is currently increasing, so the frozen platelet infusion is needed to improve the conditions of those patients.