The Bacteriological Screening of Platelet Concentrates Stored at 22 C

Platelet concentrate prepared under routine British blood bank conditions in a closed‐bag‐system was examined for bacteriological contamination. None was found. Platelet concentrate was shown to support free multiplication from minimal inocula of several pathogenic and commensal bacterial species especially at 37 C. It is the authors' opinion that if any platelet concentrate is stored at 22 C and not used immediately after preparation, then it should be screened for bacterial growth by holding a heat sealed segment of tubing containing a representative sample of fluid overnight at 37 C and then preparing a Gram‐stained film for examination before issue of the parent bag.     

细菌筛检在预防和控制血小板细菌污染方面的有效性

本研究探讨用血小板细菌筛检及24小时锁定的方法预防和控制血小板细菌污染的有效性。用BacT/A-LERT细菌培养仪对保存24小时后（22℃振荡保存）的单采血小板（机器采集的血小板）进行细菌筛检。在无菌条件下抽取5袋样品,并合并成1袋后分别接种于需氧培养液和厌氧培养液中,同时将被抽检的血小板进行锁定。接种后的培养液置培养箱中培养24小时后,如结果为阴性,则该血小板可放行。如出现阳性,对阳性结果进行菌种鉴定,并取留样样品进行复试。结果表明：8017袋单采血小板中,初筛为阳性的16袋（0.2%）,复筛确认阳性的4袋（0.05%）;进一步菌种分析显示3袋为金黄色葡萄球菌,1袋为耳状葡萄球菌。结论：血小板细菌筛检、24小时锁定作为血小板常规检测项目是非常必要的,它对于预防和控制血小板细菌污染是有效而且适宜的。     

血小板保存期间血小板计数和P-选择蛋白的变化

探讨CS 30 0 0plus血细胞分离机全密闭 5天保存袋保存的血小板数量和质量的变化 ,研究在 (2 2± 2 )℃条件下振荡和静置两种方法保存的血小板有无差异。采用SysmexF 82 0型全自动血细胞分析仪对机采血小板产品计数 ,应用酶联免疫吸附法 (ELISA)定量检测机采血小板上清液中P 选择蛋白的含量。结果显示 ,振荡与静置两种方法保存的血小板产品中血小板计数和P 选择蛋白含量均无显著性差异。随保存时间延长 ,振荡和静置保存的血小板计数逐渐减少和P 选择蛋白逐渐增多 ,其中两组内的血小板计数在保存 0 - 72小时以内均无显著性差异 ;而在保存 96 - 1 2 0小时后与保存前比较都有显著性差异。振荡保存组 0 - 72小时内 ,每相邻 1天之间P 选择蛋白量无显著性差异 ,其余各时间段均有显著性差异 ;静置保存组 0 - 72小时内各时间段均无显著性差异。结论 :①使用CS 30 0 0plus血细胞分离机全密闭 5天保存袋 ,对血小板制品的有效保存期以 3天为宜 ;②在 (2 2± 2 )℃条件下 ,振荡保存的血小板在数量和质量上并不优于静置保存的血小板。     

A General Change of the Platelet Transfusion Policy from Apheresis Platelet Concentrates to Pooled Platelet Concentrates is Associated with a Sharp Increase in Donor Exposure and Infection Rates

SUMMARY: BACKGROUND: We compare the actual with the potential donor exposure and possible infection rates in the Hanover Medical School (MHH) platelet (PLT) transfusion recipients if the current MHH standard of apheresis PLT concentrate (A-PC) supply would be replaced by a pooled PLT concentrate (P-PC) transfusion regimen. DONORS, PATIENTS, AND METHODS: The electronic records of the MHH Institute of Transfusion Medicine and the MHH Department of Medical Controlling were evaluated to assess the development of PLT needs and supply at MHH from 2003-2006. For 2006, we evaluated all PLT transfusion recipients with respect to their overall transfusion needs, classified them for low and high PLT transfusion needs, and related them to the diagnostic groups that underlie their PLT demands. We assumed a P-PC preparation procedure using 4 whole blood-derived buffy coats for all calculations for potential donor exposure. To predict the possible infection rates of an unrecognized viral infection with low prevalence in the general population to A-PC or to P-PC recipients and the influence of neutralizing agent specific antibodies (NAB), we established a mathematical contamination/infection model based on the current PLT transfusion mode and data about GBV-C virus infection among Hanover blood donors. RESULTS: From 2003 to 2006, the 1,300-1,400 persons comprising MHH apheresis donor pool covered a 36% increase in PC transfusions. The exclusive use of P-PCs instead of A-PC would require a total of 36,240-49,276 whole blood donations to meet MHH demands, corresponding to a more than 1 log step increase in donor exposure. For individual hematological patients, the change to P-PCs would imply an 80-125%, for individual surgical patients a 40-50% higher donor exposure. Our infection model revealed an approximately 4 times higher infection. CONCLUSIONS: A change to P-PC would imply a more than one log step higher donor exposure, and an unrecognized infection with a prevalence around 1% leads to an up to 4 times higher infection rate. A general change in the PC transfusion policy that favors P-PCs is dangerous and must be avoided.     

10 Years of Experience with the First Thawed Plasma Bank in Germany

BackgroundPlasma is stored at −30°C, which requires thawing before transfusion, causing a time delay between ordering and issuing of at least 30 min. In case of bleeding emergencies, guidelines strongly recommend a 2:1 transfusion ratio of RBCs and plasma. In addition, each minute delay in issuing of blood products in bleeding emergencies increases the mortality risk. To provide plasma in time in bleeding emergencies, a thawed plasma bank was introduced in 2011.SummaryThe thawed plasma bank of University Medicine Greifswald has provided 18,924 thawed stored plasma units between 2011 and 2020. The workflow in the laboratory as well as in the emergency room, the operating room, and the intensive care unit have been optimized by thawed stored plasma. In case of emergencies, the stress factor for the transfusion medicine laboratory staff has been reduced substantially. The thawed plasma bank allows to transfuse patients with massive transfusion demand at a 2:1 ratio of RBCs and plasma according to guidelines. To reduce storage time, we issue all plasma requests from the thawed plasma bank except for pediatric patients. This results in a median storage time in the thawed plasma bank of 24 h. The “just in time” availability of plasma within the entire hospital based on the thawed plasma bank has reduced precautionary ordering of plasma, and hereby the unnecessary use of plasma. After introduction of the thawed plasma bank, plasma usage decreased substantially by 24% within the first year and by 60% compared to 2019/2020. However, as the overall approach to using blood products has changed over the last 10 years due to the patient blood management initiative, quantification of the effects of the thawed plasma bank in reduction of plasma transfusion is difficult.Key Messages(1) A thawed plasma bank for the routine supply of blood products in a large hospital is feasible in Germany. (2) The thawed plasma bank allows to supply RBCs and plasma in a 2:1 ratio in bleeding emergencies. (3) The beneficial logistical effects of the thawed plasma bank are optimal if all plasma requests are supplied from the thawed plasma bank. This results in a median storage time of 24 h for thawed plasma.     

Transfusion of Fresh Platelet Concentrates to Adult Patients with Thrombocytopenia

Fresh platelet concentrates were given to 18 adult patients on 68 occasions without adverse effect. The concentrates were prepared by means of a closed-system plateletpheresis technic which permitted rapid and frequent bleeding of donors. There was a direct relationship of the amount of platelets infused to the mean posttransfusion increment. Excellent hemostatic effect was noted in 84% of patients with active bleeding when the platelet increment was 40,000/mm³ or better. Transfusion of large numbers of platelet concentrates is effective in controlling or averting bleeding in adults with thrombocytopenia and is recommended on a therapeutic and prophylactic basis.     

Clinical Effectiveness of Platelet Concentrates Prepared with or without Acidification of the Plasma

Fresh platelet concentrates prepared with or without acidification of the platelet-rich plasma were administered to 32 thrombocytopenic patients. A total of 122 transfusions were given including 60 of platelet concentrates from unmodified plasma and 62 of platelets prepared from acidified plasma. In vivo retrieval was calculated by two different and previously used formulas and found to be equivalent for acidified or nonacidified platelet concentrates by either method. Strict adherence to the details of the platelet separation technic is stressed and the possible significance of refrigeration during centrifugation is considered. Non-modified platelet concentrates are therapeutically effective. They are also economically preferable since they can be obtained as by-products of ordinary blood banking and do not prejudice the use of the plasma for separation of AHF cryoprecipitates.     

回输的血小板在体内清除机制研究进展

生理学，病理学方面的研究发现血小板在体内清除主要发生在肝脏和脾脏，但衰老和损伤的血小板被体内清除系统识别和清除的机制还并不清楚。这一机制研究的深入将有助于解决血小板低温保存后体内存活期短．不能较长期发挥作用的难题，为血小板保存提出新的策略。本文就血小扳回输体内后的清除机制，包括P-选择蛋白，GPIbα及其受体Mac-1和内源性金属蛋白酶在血小板清除进程中的作用等的研究进展作一综述。     

Sterility of Platelet Concentrates Stored at 25 C

One hundred platelet concentrates were stored at 25 C and cultured for bacterial growth on four successive days. No bacterial contamination was detected which suggests that platelet concentrates, prepared in a closed system, are sterile and remain so under these conditions.     

离心法制备少白细胞血小板的研究

本文采用密闭4联输血袋系统(PVC),用2次离心法制备的浓缩血小板(PC)解聚后,再行第3次离心以去除PC中的白细胞和红细胞;探讨了第3次离心速度对其效果的影响。经第3次450×g离心观察65例,其白细胞残留量为0.07×10~8/L;血小板回收率为全血的52.5％,平均(5.3±1.6)×10~(10)/袋。通过18袋PC对照研究证实,第3次离心对保存期间血小板质量与体外功能无影响。少白细胞PC保存3天、5天的pH值显著高于普通PC,分别为7.2±0.1,6.6±0.4;7.1±0.2,6.3±0.6(P<0.001)。血小板保存5天乳酸脱氢酶释放率显著低于普通PC(P<0.05)。经临床46例对照验证,其发热性输血反应显著下降(P<0.05),具有与普通PC相同的疗效。     

少白细胞汇集浓缩血小板的临床应用

目的观察少白细胞汇集浓缩血小板的临床效果。方法将88例血小板输注患者分为2组,A组包括血液病及肿瘤放化疗患者38例;B组包括产妇及外科术中出血患者50例。均于输注前及输注后1h和24h检测血小板计数,并计算CCI值,观察其有效率和不良反应发生率。结果 88例患者输注少白细胞汇集浓缩血小板总有效率94.32%。其中A组有效率为86.84%,不良反应发生率为10.53%。B组有效率为100.00%,不良反应发生率为2.00%。A组不良反应发生率高于B组。结论少白细胞汇集浓缩血小板临床输注安全有效,可作为单采血小板用量不足的补充,对临床术中出血患者的抢救治疗有重要应用价值。     

P01Use of the DiaMed Impact R to Test Platelet Function in Stored Platelet Concentrates

Aim The DiaMed Impact R tests platelet function under close to physiological flow conditions using cone and plate technology. A blood sample is applied to a polystyrene well and plasma proteins (eg VWF and fibrinogen) adhere to the well surface. Shear force is applied to produce arterial flow conditions leading to adhesion and aggregation of platelets via interaction of various platelet membrane glycoproteins including GPIbα and GPIIb/IIIa with vWF and fibrinogen on the well surface. The adhered platelets are quantified by an image analyser and results expressed as % well surface covered by aggregates (SC %) as an index of adhesion and average size of the aggregates (AS μm²) as an index of aggregation. The machine is designed to use whole blood and we found in preliminary studies that adhesion and aggregation do not occur when platelet concentrates (PCs) are used instead. The aim of this study was to add red cells back to PCs so that function could be studied and changes during storage followed and compared with those observed in our established in vitro assays. Method ABO compatible routine leucoreduced red cells in SAGM (1 mL) were mixed with 0.6 mL PC to give a final Hct of 35% and platelet count of 400 × 10⁶ mL^‐1. These are conditions seen in whole blood except for the reduced levels of leucocytes. Red cells diluted with platelet poor plasma were used as negative controls. The shear rate and time of activation were varied and conditions optimised. Routine PCs were then tested on days 2 and 7. Samples were also stored at 4 °C or 37 °C for 1 to 2 h before assay to see if function could be improved. Results Optimum conditions of 1800 s^‐1 and 4 min activation produced normal values of SC >7.5% and AS >25 μm² Mean values ± SD are shown below.

Pooled Platelet Concentrates Prepared in a New Blood Bank Centrifuge

Pools of platelet-rich plasma, prepared by the split-ACD technic at the donor facility, were passed through a special (ADL) centrifuge bowel to continuously trap platelets within the bowl as platelet-poor plasma was removed. The platelets were concentrated in a final volume of 125 to 150 ml. With the bowl used, flow rates of about 50 ml/min at 1,200 × g allowed concentration of 80 per cent of the platelets from the original plasma. Platelet clumping did not occur despite admixture of ABO blood groups. Recovery in vivo was equal to that observed for platelets in conventional concentrates. Divided doses of these platelet concentrates were reserved for multitransfused patients because pooling increases the risk of transmitting hepatitis. This method is a rapid, effective, semiautomated adjunct to blood-component preparation in hospital blood banks.     

单独采集血小板和浓缩血小板在保存期中的活化情况

研究单独采集血小板 (单采血小板 )和浓缩血小板在保存期中的活化情况。用流式细胞术对这两种血小板的CD62 p和CD41表达量进行测定。结果表明 :在保存 0 ,1 ,3和 5天时 ,单采血小板的CD62 p阳性率和CD41的平均荧光强度分别为 (1 8 91± 6 2 5) % ,(1 9 48± 8 2 7) % ,(2 2 82± 6 0 6) % ,(56 71± 1 1 79) %及 (8 0 9±2 38) % ,(8 1 3± 2 45) % ,(8 44± 2 51 ) % ,(1 9 87± 6 1 3) % ,而浓缩血小板的分别为 (30 65± 1 2 33) % ,(31 46± 1 1 86) % ,(32 51± 1 3 0 5) % ,(63 55± 1 3 2 7) %及 (1 0 33± 4 37) % ,(1 1 0 9± 6 61 ) % ,(1 3 46± 9 69) % ,(2 4 41± 1 0 1 5) %。二项指标均随保存时间推移而上升。对这两种血小板的计数和 pH值测定显示 ,二者均随保存时间推移而下降。在保存 0 - 3天内两种血小板的计数 ,pH值 ,CD62 p和CD41表达量无显著差异。在第 5天血小板计数和pH值出现显著下降 (P <0 0 0 1 ) ;而CD62p和CD41表达量出现显著上升 (P <0 0 0 1 )。结论 :单采血小板优于浓缩血小板     

机采血小板悬液在保存过程中凝血因子Ⅷ、Ⅸ生物活性的变化

为了研究机采血小板悬液22℃振荡保存不同时间的凝血因子Ⅷ、Ⅸ生物活性的变化,采用SYSMEXCA-1500型全自动血凝仪对用CS-3000plus血细胞分离机采集的18份血小板悬液于22℃振荡保存条件下,测定0、12、24、48、72、96、120小时7个时间段的FⅧ∶C和FⅨ∶C的活性。结果表明:机采血小板FⅧ∶C在0时活性为(100.51±44.02)%,保存12-120小时,其活性衰减了10%-40%;FⅨ∶C在0时活性为(120.93±20.50)%,保存24-120小时,其活性衰减了10%-35%。结论:机采血小板悬液于22℃振荡保存时凝血因子Ⅷ、Ⅸ仍保持有较高的生物学活性。     

An Evaluation of Anticoagulant Solutions Used in the Preparation of Platelet Concentrates*

Radiochromate-labeled platelet concentrates have been prepared following collection of blood into solutions of EDTA, ACD (formula A), and a more acidic form of citrate-dextrose—ACD ‘S’. Platelet yield was greatest when EDTA was used but following transfusion, relatively few platelets survived in circulation as viable units. In terms of over-all efficiency both solutions of ACD were superior to EDTA. Platelet life span in circulation was unaffected by the anticoagulant used for the collection of blood and would appear to be influenced by both age-dependent and random processes. Surface scintillation counting suggested that in man the majority of effete platelets are normally removed in the liver and that the spleen plays a secondary, but not unimportant, role in this process.     

UVC Irradiation for Pathogen Reduction of Platelet Concentrates and Plasma

Besides the current efforts devoted to microbial risk reduction, pathogen inactivation technologies promise reduction of the residual risk of known and emerging infectious agents. A novel pathogen reduction process for platelets, the THERAFLEX UV-Platelets system, has been developed and is under clinical evaluation for its efficacy and safety. In addition, proof of principle has been shown for UVC treatment of plasma units. The pathogen reduction process is based on application of UVC light of a specific wavelength (254 nm) combined with intense agitation of the blood units to ensure a uniform treatment of all blood compartments. Due to the different absorption characteristics of nucleic acids and proteins, UVC irradiation mainly affects the nucleic acid of pathogens and leukocytes while proteins are largely preserved. UVC treatment significantly reduces the infectivity of platelet units contaminated by disease-causing viruses and bacteria. In addition, it inactivates residual white blood cells in the blood components while preserving platelet function and coagulation factors. Since no photoactive compound needs to be added to the blood units, photoreagent-related adverse events are excluded. Because of its simple and rapid procedure without the need to change the established blood component preparation procedures, UVC-based pathogen inactivation could easily be implemented in existing blood banking procedures.     

A Simple Method for Obtaining Platelet Concentrates Free of Aggregates

A simple method is presented for obtaining platelet concentrates in a homogeneous suspension by centrifuging platelet-rich plasma at 25 C and allowing the centrifuged platelets to incubate at this temperature for 30 minutes before resuspending them.     

Transfusion of Platelet Concentrates Prepared from Acidified Platelet-Rich Plasma*

With the use of Aster's and excess ACD solutions, the recovery of chromium⁵¹-labeled platelets was greater, and the sequestration phenomenon decreased in patients without hematologic disease, compared with preparations collected in the normal amounts of ACD as the anticoagulant. Analysis of platelet counts following transfusions of platelet concentrates demonstrated a significant increase of platelets in transfused leukemic patients using acidified preparations as compared with those collected in normal amounts of ACD. The use of additional ACD solution which is routinely available in the blood bank appears to be a satisfactory method to prepare the acidified platelet concentrates.