Transfusion
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The American Association of Blood Banks (AABB) requires that blood samples used for pretransfusion testing of recently transfused (or pregnant) patients must be obtained within 3 days of scheduled transfusions. This requirement, which became effective in July 1988, amended Standard G2.000 of the AABB, which previously required that pretransfusion testing must be done on blood samples obtained within 2 days of scheduled transfusions. The present study was designed to estimate the risk associated with adopting the amended version of Standard G2.000. ⋯ Thirteen of the 60 patients were found to have newly detectable antibodies within 83 hours of a sample reported to be negative for the new antibody. Had the amended version of Standard G2.000 been in effect, the detection of some of these antibodies might have been delayed up to 24 hours. It was estimated that the implementation of the new AABB requirement at the authors' institution could potentially place about 1 in 3000 transfused patients at risk for an acute or delayed hemolytic transfusion reaction.
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The risks of transfusion-associated infectious disease have led to a reassessment of transfusion practice, which in turn has resulted in a trend toward the reduction of homologous transfusion. This reduction is primarily due to the initiation of hemotherapy at more severe levels of anemia. The optimum threshold for the initiation of transfusion therapy, or the transfusion trigger (TT), is unknown. ⋯ Oxygen delivery fell after ET (18.9 vs. 11.1 cc/kg/min, p less than 0.001), but there was no significant change in oxygen consumption after ET. The unanesthetized animals adapted well to severe anemia and experienced no adverse effects on their long-term survival in this setting, which suggests that the reduction of the TT to a Hct of 15 percent in normal animals is safe. Adoption of this TT could result in a significant reduction in the requirements for homologous transfusion with its attendant risks.
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Most commercial blood warmers are unable to warm blood components to greater than 35 degrees C at rapid flow rates (greater than 100 mL/min) because of problems with inefficient heat transfer and resistance to the flow of blood through the instrument's tubing. A new blood warmer, using a closed-flow 40 degrees C counter-current water bath and large-bore tubing, is able to warm cold (10 degrees C) packed red cells to temperatures greater than 35 degrees C even at flow rates of 500 mL per minute. ⋯ In vivo survivals of chromium-51-labeled warmed autologous red cells were greater than 75 percent in four volunteers and 49.5 percent in the fifth volunteer, whose abnormally low unwarmed red cell ATP level suggested a storage problem. Thus, this blood warmer, which warms blood efficiently at high flow rates, causes no red cell damage, even with prolonged exposure of old red cells to the 40 degrees C heat exchanger.
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HLA and granulocyte-specific antibodies have been implicated in the production of transfusion-related acute lung injury (TRALI). Reported here is a case that suggests that the patient's preexisting condition may play an important role in determining whether TRALI develops upon transfusion of blood products containing anti-white cell (WBC) antibodies. A 29-year-old woman with thrombotic thrombocytopenic purpura (TTP) underwent an uneventful 1.5-volume plasma exchange, which was followed by the transfusion of 2 red cell (RBC) units. ⋯ Serologic studies demonstrated that the serum from the second RBC donor had no HLA antibodies but did have a granulocyte-specific antibody (anti-NB2) that caused the agglutination of the recipient's granulocytes, which were NB2 positive. Serum from the donor of the first RBC unit and serum from the donors of units used in the exchange had no HLA or granulocyte-specific antibodies that reacted with the recipient's WBCs. Because the donor implicated in this reaction had a history of 21 blood donations, none of which had been associated with a transfusion reaction, we suggest that the patient's preexisting condition played a significant role in this episode of TRALI, owing to the granulocyte-specific antibody.