Transfusion
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Hetastarch, the currently marketed preparation of hydroxyethyl starch, affects coagulation by prolonging partial thromboplastin, prothrombin, and bleeding times; by lowering clotting proteins such as fibrinogen via hemodilution; by lowering clotting factor VIII (coagulant, von Willebrand antigen, and von Willebrand activity) to a greater degree than can be explained simply by hemodilution (i.e., presumably factor VIII affected by both hemodilutional plus additional, independent effects); and, finally, by shortening thrombin, reptilase, and urokinase-activated clot lysis times. Pentastarch, a new analog of hetastarch, was found to exert lesser effects on blood coagulation, despite its greater hemodiluting properties. ⋯ Even when plasma hydroxyethyl starch levels were similar, pentastarch seemed to alter the results of coagulation assays to lesser degree than did hetastarch, which suggests the possibility of greater safety. Therefore, pentastarch may be a desirable drug, not only for leukapheresis, but also for plasma volume expansion in trauma and surgical patients who often have additional hemostatic abnormalities that place them at increased risk of hemorrhage.
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Human babesiosis, a parasitic disease transmitted by the tick, Ixodes dammini, was confined previously to limited areas of the northeastern United States. It is a rare but potentially life-threatening complication of transfusion. Red cells and platelets prepared from asymptomatic donors have been implicated in transfusion-transmitted cases. ⋯ Blood donors from an endemic area were tested for antibody to Babesia microti during the summer. Only 3.7 percent of the 779 donors were seropositive, compared with 4.7 percent (p greater than 0.05) of donors from a nonendemic area. An epidemiologic survey of seropositive and matched seronegative controls demonstrated no significant differences that would assist in screening donors.
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The use of 534 units of fresh-frozen plasma (FFP) during 160 transfusion episodes in 135 consecutive patients was reviewed. Only 27 percent of transfusions were indicated by a need for replacement of labile coagulation factors. ⋯ Data from other institutions and national sources support the hypothesis that much of the increase in FFP use over the last decade is related to decreases in whole blood availability rather than to use for labile coagulation factor replacement. The use of FFP and red cells as a substitute for, or in preference to, whole blood may have significant adverse implications in terms of the cost and safety of blood transfusion.
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A three-part study to determine the reasons for fresh-frozen plasma (FFP) transfusions at hospitals in southeastern Wisconsin was conducted. During a 1-month period, hospital transfusion services reported that patients undergoing open-heart surgery received 42 percent, medical patients 26 percent, noncardiac surgery patients 23 percent, neonatal patients 1 percent, and other patients 7 percent of the FFP transfused. In the second phase of the study, the records of 102 patients receiving FFP during a 1-month period at two teaching hospitals were reviewed. ⋯ They judged that the FFP transfusion was effective in 47 percent of transfusion episodes and ineffective in only 6 percent. These findings indicate that FFP is used mainly as a source of coagulation factor replacement in hospitals served by The Blood Center of Southeastern Wisconsin, that justification for FFP use rarely is provided in patient records, that both FFP and RBCs are frequently transfused together, and that clinicians believe FFP is beneficial for their patients. Educational efforts addressing appropriate use of FFP should be initiated.