The role of sodium citrate during extended cold storage of platelets in platelet additive solutions

Background

Cold-stored platelets are increasingly being used to treat bleeding. Differences in manufacturing processes and storage solutions can affect platelet quality and may influence the shelf life of cold-stored platelets. PAS-E and PAS-F are approved platelet additive solutions (PAS) in Europe and Australia, or the United States respectively. Comparative data are required to facilitate international transferability of laboratory and clinical data.

Study Design and Methods

Single apheresis platelets from matched donors (n = 8) were collected using the Trima apheresis platform and resuspended in either 40% plasma/60% PAS-E or 40% plasma/60% PAS-F. In a secondary study, platelets in PAS-F were supplemented with sodium citrate, to match the concentration in PAS-E. Components were refrigerated (2–6°C) and tested over 21 days.

Results

Cold-stored platelets in PAS-F had a lower pH, a greater propensity to form visible (and micro-) aggregates, and higher activation markers compared to PAS-E. These differences were most pronounced during extended storage (14–21 days). While the functional capacity of cold-stored platelets was similar, the PAS-F group displayed minor improvements in ADP-induced aggregation and TEG parameters (R-time, angle). Supplementation of PAS-F with 11 mM sodium citrate improved the platelet content, maintained the pH above specifications and prevented aggregate formation.

Discussion

In vitro parameters were similar during short-term cold storage of platelets in PAS-E and PAS-F. Storage in PAS-F beyond 14 days resulted in poorer metabolic and activation parameters. However, the functional capacity was maintained, or even enhanced. The presence of sodium citrate may be an important constituent in PAS for extended cold storage of platelets.     

Comparison of two platelet additive solutions

The use of an additive solution for substitution of plasma for storage of leukodepleted platelet concentrates can have many advantages. In this study, a comparison was made between two platelet additive solutions: one containing citrate and acetate (PAS-II), the other also supplemented with additional salts such as magnesium, and with gluconate (Composol-PS). Donor-dependent differences were avoided by applying a paired experimental design (n = 10). The platelet concentrates were prepared by pooling five buffy coats and the additive solution, and prestorage filtration was utilized to remove leucocytes to well below 1 x 106. Storage of platelet concentrates up to 9 days after blood collection revealed that platelet concentrates in Composol-PS maintained an almost constant pH of on average 6.93 from day 2 through day 7, and at 6.90 at day 9. This was in contrast to PAS-II, which showed a gradually decreasing pH from on average 6.97 at day 1 to 6.86 at day 9. In all units stored in both solutions the swirling effect was present during 9 days of storage. In conclusion, both additive solutions allow storage of platelets, derived from pooled buffy coats, for up to 9 days after collection of the whole blood, with maintenance of good quality in vitro. Composol-PS has a slightly better buffering capacity, reflected as a more constant pH throughout the storage period.     

I am the 9%: Making the case for whole‐blood platelets

Over the last 15 years, there has been a trend in the United States towards the increasing use of apheresis platelet (AP) concentrates over whole‐blood‐derived platelets (WBP). Although 1‐h‐ and 24‐h‐corrected count increments tend to be higher with AP, this does not translate into improved haemostatic efficiency when used to prevent bleeding in haematology/oncology patients. WBP expose the recipient to more donors than apheresis products. However, recent studies have shown no significant differences in the rates of bacterial contamination, human leukocyte antigen alloimmunisation, RhD alloimmunisation, transfusion‐related acute lung injury or febrile non‐haemolytic transfusion reactions between these two products. Given the overall low rates of virally contaminated units in the era of nucleic acid testing and rigorous donor screening, the difference in donor exposures of 4–6 vs 1 has minimal clinical relevance. Although studies point to a marginally increased risk of donor adverse events associated with WBP, the absolute risk is too miniscule to act as a deterrent to making whole‐blood donations. Both types of platelet concentrates should therefore be considered clinically equivalent; in this light, the most responsible use of the community donor resource pool, which both optimises the utility of a whole‐blood donation and meets the clinical needs of thrombocytopenic recipients, is to have a mix of both types of platelet products so as to mitigate the risk of shortages.     

Apheresis platelets: Emerging issues related to donor platelet count,apheresis platelet yield,and platelet transfusion dose

Emerging issues in stimulating apheresis platelet donors with platelet growth factors, the relative costs of apheresis and random donor platelet concentrates, optimal platelet transfusion dose, and leucoreduction of platelet products have caused renewed debate regarding apheresis products vs. random, pooled concentrates. The future role of apheresis products in platelet transfusion therapy will in large part be determined by costs, which are increasingly recognized to be influenced by donor platelet count, apheresis yield, and platelet transfusion dose. J. Clin. Apheresis 13:114–119, 1998. © 1998 Wiley-Liss, Inc.     

PAS or plasma for storage of platelets? A concise review

Platelet additive solutions (PASs) are becoming increasingly popular for storage of platelets, and PAS is steadily replacing plasma as the storage medium of platelets. PASs are electrolyte solutions intended for storage of platelets, and they are used to modulate the quality of the platelets by adding specific ingredients. All currently available PASs contain acetate. Acetate reduces the amount of glucose that is oxidised into lactic acid and thereby prevents the lowering of pH, which decreases platelet quality. Furthermore, the oxidation of acetate leads to the production of bicarbonate, which serves as buffer. The presence of potassium and magnesium in PAS prevents the lowering of pH and reduces the degree of spontaneous activation of the platelets during storage. In the hospital, platelets stored in PAS result in about half of the number of allergic transfusion reactions as compared with platelets in plasma. Recovery and survival after transfusion, as well as corrected count increments, are at least as good for platelets in PAS as for plasma, and recent data suggest they may even be better. Therefore, with the current generation of PASs, PAS should be preferred over the use of plasma for the storage of platelet concentrates.     

冰冻血小板与新鲜血小板的疗效比较

目的比较冰冻血小板和新制备的血小板的在临床上的应用效果。方法选268例新制备的血小板与296例冰冻的血小板输注病例,观察两组输注血小板前后的临床表现并进行血小板的计数。结果在564例病案中,输注新制备血小板后的患者外周血血小板上升的程度和总有效率明显高于输注冰冻血小板的患者,两者之间差异有显著性(P<0.05)。结论输注新鲜血小板或冰冻血小板均能达到控制及预防出血的治疗作用,并且提升机体血小板数值,虽然新鲜血小板的疗效优于冰冻血小板,但冰冻血小板可以在抢救危重患者时代替机采新鲜血小板。     

Current status of additive solutions for platelets

The storage of platelets in additive solution (PAS) had lagged behind red cell concentrates, especially in North America. The partial or complete removal of anticoagulated plasma and storage of platelet concentrates in AS presents many advantages. The PAS can be formulated to optimize aerobic metabolism or decrease platelet activation, thus abrogating the platelet storage lesion and potentially improving in vivo viability. Plasma removal has been shown to reduce allergic reactions and the plasma harvested could contribute to the available plasma pool for transfusion or fractionation. PAS coupled to pathogen reduction technology results in a platelet product of equivalent hemostatic efficacy to conventionally stored platelets. Given the above, the likely future direction of platelet storage will be in new generation designer PAS with an extended shelf life and a superior safety profile to plasma stored platelets. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.     

医用电解质溶液作添加液制备汇集少白细胞血小板

目的采用医用电解质溶液作添加液(PAS),建立1种白膜法制备添加液汇集少白细胞血小板(PAS汇集BC-PCs)的方法。方法从400ml全血中分离白膜层,容量35—40ml,放(22±2)℃静置过夜,将ABO同型的6袋白膜汇集,加220g添加液(90%复方电解质注射液、8%ACD-A血液保养液和2%含量为50g/L的碳酸氢钠注射液的混合液)稀释白膜,汇集后的白膜在(22±2)℃中,以300×g离心10min,将上层的富含血小板悬液再经白细胞滤除器过滤去除白细胞,并转移到血小板保存袋内,即制备成1个成人治疗量的PAS汇集BC-PCs,制备过程在一个特制的密闭系统内完成。结果共制备30个成人治疗量的PAS汇集BC-PCs,其容量为(270±32)ml、血小板含量为(2.96±0.31)×1011、WBC混入量为(1.3±0.2)×106、RBC混入量为(5.8±1.1)×109、CD62P表达率为(22.5±10.6)%。保存8d后的pH为7.14±0.04、低渗休克反应率(HSR)为(54.0±8.2)%、CD62P表达率为(45.7±13.8)%。结论由复方电解质注射液、ACD-A保养液和碳酸氢钠注射液的混合液为添加液汇集血小板的方法可行。     

Platelet transfusion refractoriness responding preferentially to single donor aphaeresis platelets compatible for both ABO and HLA

Platelet transfusion refractoriness is challenging to manage. When human leucocyte antigens (HLA)‐sensitized patients fail to respond to HLA‐matched (HLA‐m) platelets, non‐immune destruction may be assumed, and collections of HLA‐m platelets abandoned. We report cases of highly HLA‐sensitized patients whose only satisfactory platelet transfusion responses were consistently associated with products compatible for both HLA‐ and ABO‐matched (HLA‐m/ABO‐m) platelets, and in whom unsatisfactory increments occurred if either form of major incompatibility was permitted (HLA‐u or ABO‐u). Absolute platelet increments (APIs) were measured and classified as satisfactory if ≥10 and unsatisfactory if <10. Patient 1, age 59 years, group O, with myelodysplastic syndrome/acute myelogenous leukemia (MDS/AML), was unresponsive to either fresh ABO‐m or HLA‐m platelets. Of 17 HLA‐m platelets, satisfactory responses occurred for 75% of HLA‐m/ABO‐m units, and failures for 100% of HLA‐m/ABO‐u, with mean API differing significantly (14·1 vs 1·1, P = 0·0059). Of 36 HLA‐m platelets given to patient 2, age 49 years, group O, Gravida 2 Para 2, with severe aplastic anaemia, a satisfactory response occurred with 75% of HLA‐m/ABO‐m units, and failures for 63% of the HLA‐m/ABO‐u (mean API 26·7 vs 7·6, P = 0·008). Increment failures from HLA‐m platelets need not imply intractable refractoriness. If resources permit, selection of HLA‐m/ABO‐m platelets may optimise the incremental response.     

The swirling phenomenon in stored platelets is influenced by their endogenous serotonin

The presence of the swirling phenomenon is useful to define platelet concentrates that are suitable for transfusion. If it is possible to identify donor-related factors which are related to persisting swirling during storage, it is possible to select platelet donors. Endogenous platelet serotonin content is stable and easily measured and related to agonist-induced serotonin secretion. During a 3-month period, the swirling in 825 single donor platelet concentrates was controlled before issue. Endogenous serotonin, % serotonin release and swirling were tested in 21 concentrates with poor or no swirling during storage. Sixty-three concentrates were randomly selected from the routinely prepared platelet concentrates and were routinely tested with the same analyses on days 1 and 7. To evaluate an obvious effect of endogenous serotonin on the swirling phenomenon, eight platelet concentrates prepared from buffy coat, each from four donors, were divided. One part was stored in the presence of 8.5 micromol serotonin L-1, and analysed as the control concentrates. The endogenous serotonin content in the 'low- swirling' concentrates was significantly lower than in the control group (P < 0.001). PCO2 and pH were significantly lower, and PO2 and MPV significantly higher than in the controls. In the control group, swirling after 7 days was significantly correlated with serotonin release. In the eight buffy-coat concentrates enriched in endogenous serotonin, both swirling and the percentage serotonin release were improved after storage for 10 days, compared with nonenriched concentrates. This study suggests that endogenous serotonin content and serotonin release are factors that may be of significance concerning preservation of the swirling phenomenon in platelet concentrates during storage.     

不同模式制备浓缩血小板的临床应用研究

目的分析不同汇集白膜层(PBC)法制备浓缩血小板在输血患者中的输注疗效以及血小板质量。方法选取承德医学院附属医院血液科2017年1月至2018年11月收治的特发性血小板减少性紫癜患者90例作为研究对象,根据随机数字表法分为A、B、C 3组,每组30例。A组使用全血室温过夜PBC法制备的浓缩血小板,B组使用白膜室温过夜法制备的浓缩血小板,C组使用即时PBC法制备的浓缩血小板。比较3种模式制备浓缩血小板的质量以及患者临床应用效果,并记录不良反应。结果3组红细胞混入量、血小板数量、血小板容量以及pH值比较差异均无统计学意义(P>0.05);3组患者输注1、24h后血小板计数(PLT)均较输注前显著升高,输注24h后PLT均较输注1h后降低(P<0.05);3组患者输注1、24h后PLT以及PLT校正增加值(CCI)比较差异均无统计学意义(P>0.05);3组患者不良反应发生率比较差异均无统计学意义(P>0.05)。结论3种模式制备的浓缩血小板质量以及患者的输注疗效、安全性均相当。     

A prospective randomized study of three types of platelet concentrates in patients with haematological malignancy: corrected platelet count increments and frequency of nonhaemolytic febrile transfusion reactions

We prospectively randomized 51 patients with haematological malignancy requiring platelet concentrates (PCs) to receive either single donor plateletpheresis products (SD-PC), PCs made from pooled buffy coats (BC-PC) or pooled units of platelets made by the platelet-rich plasma method (PRP-PC). The leucocyte content of each type of PC was 0.33 (0.03–13.5), 5.68 (0.19–99.0) and 365 (65–910) × 10⁶; median (range), respectively; P  < 0.0001. All red cell transfusions were leucodepleted by filtration. Statistical comparison of the probability of the occurrence of a nonhaemolytic febrile transfusion reaction (NHFTR) following transfusion of PCs in patients in each group showed a significant decrease for the SD-PC and BC-PC groups (0.031 and 0.038, respectively) when compared with PRP-PC (0.171); P  =0.001. The actual corrected platelet count increments (CCI) at 1–6 and 18–24 h post-transfusion for all three types of PC did not differ significantly. We conclude that transfusion of PRP-PC is associated with a significant increase in NHFTR.     

两种血小板制剂应用于儿科血液病的临床观察

目的观察并比较机器单采法及手工法分离制备血小板制剂用于儿科血液病输注的效果。方法输注机器单采血小板患儿463例次为机采制剂组,输注手工分离血小板制剂患儿155例次为手工制剂组,分别在输注后24、48及72h作外周血血小板计数,观察临床止血效果、有无输血反应发生,计算血小板计数增加校正指数(CCI)、血小板回升率(PPR)、输注无效率、输血反应发生率等指标。结果输注后24、48、72h,机采制剂组:CCI分别为18.9、15.4、14.1,PPR分别为33.4%、27.8%、25.0%;手工制剂组:CCI分别为11.3、9.4、2.9,PPR分别为20.3%、10.3%、3.8%;机采法制剂组均明显高于手工制剂组(P<0.01)。机采制剂组输注无效率10.58%、输血反应发生率3.02%,手工制剂组相应为32.90%及11.61%,机采组虽都明显低于手工组,但两组均达到较好的临床止血目的,组间无差异。结论输注机器单采血小板制剂能更有效地提高血液病患儿的血小板值,减少其血小板输注无效及输血反应的发生。     

Economic consequences of alterations in platelet transfusion dose: analysis of a prospective, randomized, double-blind trial

BACKGROUND: In recent years, decreasing financial resources led to the use of lower-dose platelet components. However, the economic consequences of the use of such components have not been carefully studied. STUDY DESIGN AND METHODS: A formal economic analysis was conducted of a recently reported, prospective, randomized, double-blind study examining the platelet dose-response relationship in nonrefractory patients. The economic analysis used a decision analysis model, conducted from the hospital's perspective and based directly on the observed clinical data and on institutional cost structures. RESULTS: The decision analysis model estimated that a 38-percent reduction in mean platelet dose, within the commonly prescribed dose range, would result in the average patient's requiring approximately 60 percent more transfusions in the posttransplant period (8 vs. 5; p = 0.05), which would result in an estimated 60-percent increase in the median cost to the hospital ($4486/patient vs. $2804/patient [in 1996 US dollars], p = 0.05). CONCLUSION: Efforts to decrease costs by utilizing lower-dose single-donor platelet transfusions are predicted to result in a disproportionate increase in the number of transfusions per patient, with a corresponding increase in overall hospital transfusion costs.     

血小板添加剂研究进展

使用血小板添加剂（PAS）部分或者全部替代血浆常温保存血小板具有许多优点，例如可以避免输注大量血浆引起的发热、过敏反应以及循环超负荷；另外可以改善保存环境使血小板活性与止血功能维持在较高水平，节省大量血浆用于其他目的，便于血小板制品病原体灭活等。近20余年来，对于血小板添加剂的研究一直是一个热点，不同配方的血小板添加剂不断有报道，对血小板的保护效果也越来越好。本文就对血小板添加剂的组成成分、各成分的作用、体内外保存效果等研究进展进行了综述。     

Acute hemolytic transfusion reaction in a pediatric patient following transfusion of apheresis platelets

The practice of transfusing ABO-incompatible platelets, driven primarily by concerns about inventory management, has been considered generally safe because the accompanying plasma is usually diluted in the recipient's total blood volume. However, if the platelet product contains a large volume of plasma or a high concentration of incompatible isoagglutinin, there may be hemolysis of the recipient's red cells. Patients with a small blood volume, such as babies and children, are considered to be at particular risk for such a complication. We describe the case of a baby who suffered massive hemolysis of her group A red cells after transfusion of group O Apheresis Platelets containing a high-titered anti-A isoagglutinin. We also offer a review of the literature on this subject and recommendations to avoid acute hemolytic reactions as a result of platelet transfusion.     

Single-donor platelets reduce the risk of septic platelet transfusion reactions

BACKGROUND: Septic platelet transfusion reactions (SPTRs) are the most common, serious risk of transfusion. Because SPTRs result from donor skin flora or asymptomatic bacteremia, the use of single-donor platelets (SDPs) has been proposed to reduce the risk of SPTRs from the risks with pools of platelet concentrates (PCs). STUDY DESIGN AND METHODS: Beginning in 1986, all febrile transfusion reactions were evaluated by culture of the platelet bag. Confirmed SPTRs were identified by isolation of the same bacteria from the bag and the patient's blood or by positive Gram's stain of the bag that confirmed a positive platelet culture. In 1987, a program to minimize PC use in favor of SDP use was initiated as a means of reducing SPTRs. RESULTS: In 12 years, the use of SDPs increased from 51.7 percent to 99.4 percent of all platelet transfusions at one institution. SPTRs fell from three events in 1 year to the current rate of one event per year. The incidence of SPTRs decreased from 1 in 4,818 transfusions to 1 in 15,098 transfusions. The rate of SPTRs due to PCs was 5.39 times higher than that of SPTRs due to SDPs (95% CI, 1.89,12.9). CONCLUSION: The use of SDPs is a simple means of reducing SPTRs. Other measures such as sterilization will be required to eliminate all SPTRs.     

改良血小板添加液低温液态保存血小板的形态及功能研究

本研究探讨使用改良的血小板添加液替代70％自体血浆在低温（10℃）液态条件下对血小板的保存效果。采集6名供者单采血小板,每一名供者单采血小板平均分为3组,A组（常规保存组）加入100％血浆、22℃保存：B组（添加液10℃保存组）加入70％PAS—ⅢM／30％血浆、10℃保存;C组（冰冻保存组）加入100％血浆和海藻糖、-85℃保存;另设D组（血浆4℃保存组）加入100％血浆、4℃保存,作为扫描电子显微镜对照组。A、B组在第1、5、7、9天取样,C组在20天后复苏取样,分别检测CD62p、HSR、PAgT、LDH的变化。血浆常温组、添加液低温组于保存后第3、9天取样扫描电镜观察,血浆低温组于保存后第3天取样观察．冰冻组在20天后复苏取样观察,同时使用新鲜血小板作为对照。结果表明,保存期内随保存时间延长,A组和B组CD62p表达增加,HSR和最大聚集率降低;A组的LDH释放、CD62p表达、HSR、血小板最大聚集率与B组比较有显著统计学差异（P〈0．05）。C组LDH释放明显较其他两组增多,但CD62p表达较少（P〈0．05）。A、B组血小板形态保持较好,C组血小板形态保持差。结论：改良的PAS—ⅢM保存液能够替代血浆用于血小板的保存,在低温条件下能够很好地保护血小板的功能,保存效果优于血浆常温保存。