Transfusion
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The effect that a prospective review of blood and blood component utilization had during a 1-year period at an 850-bed tertiary-care teaching hospital is reported. The review process, which has been in operation for 18 years, is based on institutionally developed usage guidelines for blood, fresh-frozen plasma (FFP), platelets (Plts), and cryoprecipitate (Cryo). The guidelines were developed by the hospital's Transfusion Medicine Committee. ⋯ Screening values used in the initial evaluation of each order are: hematocrit, less than or equal to 27 percent (0.27) for blood; prothrombin time, greater than or equal to 16 seconds, and/or activated partial thromboplastin time, greater than or equal to 60 seconds, for FFP; bleeding time, greater than or equal to 16 minutes and/or a platelet count of 20 to 100 x 10(3) per mm3 (20-100 x 10(9)/L), as related to clinical conditions, for Pits; and fibrinogen less than or equal to 120 mg per dL (1.2 g/L) for Cryo. Also taken into consideration is the stated clinical indication, which is provided when the requisition is submitted. As a result of the prospective review, orders for blood and/or components for 114 patients were canceled, and 51 patients received 207 blood components that were more appropriate for the clinical situation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Active blood warming is a recent practice and arises out of conflicting needs. On the one hand, the safety and preservation of blood require refrigerated storage and delivery up to the moment of transfusion. On the other hand, modern methods of very rapid transfusion in resuscitation would cause clinically dangerous hypothermia if unmodified, ice-cold blood were to be so transfused. ⋯ The most common systems now in use are in-line warmers, most of which are not adequate for the type of rapid-transfusion systems currently available. Countercurrent in-line blood warmers and the method of rapid warm saline admixture can both be used successfully for rapid, massive transfusions. Blood warming is seldom necessary or desirable for elective transfusions at conventional rates, even for patients with cold autoagglutinins.
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Randomized Controlled Trial Clinical Trial
Lack of efficacy of tranexamic acid in thrombocytopenic bleeding.
A controlled, randomized, double-blind study was performed to assess the effect of the oral antifibrinolytic agent tranexamic acid in patients with amegakaryocytic thrombocytopenia as regards their need for platelet transfusions and the number of bleeding episodes experienced. Each patient served as his or her own control and received sequential, randomized courses of either tranexamic acid or an identical placebo. The need for platelet transfusions due to bleeding and the total number of bleeding episodes were compared for tranexamic acid and placebo courses. ⋯ Of three patients who completed the full study, none had a reduction in the need for platelet transfusions. Moreover, in the eight patients who participated in the study, there was no reduction in number of bleeding episodes during tranexamic acid treatment as compared to the number with placebo. Our data indicate that the prophylactic administration of tranexamic acid does not decrease dependence on platelet transfusions or decrease bleeding episodes in patients with bleeding due to amegakaryocytic thrombocytopenia.
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To determine whether untreated mild coagulopathy in patients with no evidence of clinical bleeding is associated with an increased risk of hemorrhage after paracentesis or thoracentesis, retrospective examination was conducted of 608 consecutive procedures for which prothrombin time (PT), partial thromboplastin time (PTT), platelet (Plt) counts, and preprocedure and postprocedure hemoglobin concentrations were available. There was no increased bleeding in patients with mild to moderate coagulopathy (defined as PT or PTT up to twice the midpoint normal range or pit count of 50 to 99 x 10(3) per microL [50-99 x 10(9)/L]). However, patients with markedly elevated serum creatinine levels (6.0 to 14.0 mg/dL [530-1240 mumol/L]) had a significantly greater average hemoglobin loss (-0.82 +/- 1.3 g/dL [-8 +/- 13 g/L], n = 11) than patients with normal serum creatinine levels (-0.12 +/- 0.88 g/dL [-1 +/- 9 g/L], n = 450) (p = 0.011). ⋯ The most common diagnosis for patients who had paracentesis was alcoholic liver disease (72%); for those having thoracentesis, it was infection (37%). It can be concluded that, for these patients, prophylactic plasma or platelet transfusions are not necessary. Patients with markedly elevated serum creatinine deserve close postprocedure observation.
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The technique of freezing blood platelets has proven very useful in transfusion support of some patients who have become alloimmunized by prior transfusions. Although transfused frozen platelets have an acceptable life span in vivo, functional defects have been found when these cells were tested in vitro. The adhesive properties of frozen platelets were investigated by use of a modified Baumgartner chamber to perform paired perfusion studies of fresh versus frozen platelets or fresh versus 5-day-stored platelets from the same whole blood unit. ⋯ Frozen platelets exhibited a significant decrease in platelet adhesion as compared to fresh platelets from the same unit; adhesion of frozen platelets was only 53 percent of that of fresh platelets (p = 0.04). A slight, but insignificant decrease was noted with platelets stored for 5 days (86%, p = 0.197). These findings indicate that frozen-thawed platelets have a significant defect in adhesive capacity as compared to fresh platelets, and that platelets stored under blood bank conditions for 5 days maintain adhesive capacity well.