Prestorage universal WBC reduction of RBC units does not affect the incidence of transfusion reactions

BACKGROUND: Febrile nonhemolytic transfusion reaction (FNHTR) has been identified as a pivotal reason for prestorage universal WBC reduction. A regional blood center implemented universal prestorage WBC reduction for RBCs on January 1, 2000. Whether prestorage universal WBC reduction of RBC units will affect FNHTR is not known. STUDY DESIGN AND METHODS: All reports of RBC transfusion reactions at Barnes-Jewish Hospital submitted for evaluation to the blood bank, before and after the implementation of WBC reduction of RBCs, were retrospectively evaluated. RESULTS: For the 36,303 allogeneic RBC transfusions administered in 1999, 85 reactions (0.23%) were reported. These reactions were classified as FNHTR in 43 cases, allergic in 13, delayed hemolytic in 19, and miscellaneous in 10. For the 31,543 non-WBC-reduced RBC transfusions performed in 1999, 78 reactions (0.25%) were reported. These reactions were classified as FNHTR in 39 cases, allergic in 13, delayed hemolytic in 19, and miscellaneous in 7. In the first half of 2000, 32 reactions (0.20%) were reported for 16,093 prestorage WBC-reduced RBC transfusions (p = 0.41). There were 13 FNHTRs and 10 allergic, 7 delayed hemolytic, and 2 miscellaneous reactions. The use of prestorage WBC-reduced RBCs did not significantly affect the rate of reactions classified as allergic (0.04% in 1999; 0.06% in 2000; p = 0.43) or as FNHTR (0.12% in 1999; 0.08% in 2000; p = 0.33). For all patients, universal WBC reduction in 2000 did not reduce the rate of FNHTR from the rate seen with selective bedside WBC reduction, the practice used in 1999 (0.12% in 1999; 0.08% in 2000; p = 0.36). CONCLUSION: No significant difference was found in the incidence of transfusion reactions in patients receiving prestorage WBC-reduced RBCs and non-WBC-reduced RBCs. In addition, no difference was found in transfusion reaction rates when periods of prestorage universal WBC reduction were compared to those of selective WBC reduction.     

Reduction of febrile but not allergic reactions to RBCs and platelets after conversion to universal prestorage leukoreduction

BACKGROUND: Between January 1995 and November 1998, at Yale-New Haven Hospital, 25 percent of RBCs transfused were processed through prestorage or bedside leukoreduction filters, chosen on a per patient basis (selective leukoreduction [SLR]). Between January 1995 and July 1999, 30 percent of platelet concentrates (PCs) were infused through bedside leukoreduction filters. In an attempt to decrease febrile nonhemolytic transfusion reactions (FNHTR), a change was made from SLR to universal prestorage leukoreduction (UPL) for RBCs between November 1998 and December 1999 and for random donor PCs between July 1999 and January 2000. FNHTR and allergic transfusion reactions (ATR) reported from January 1995 through December 2002 were reviewed. STUDY DESIGN AND METHODS: For retrospective observational analysis, blood bank data were available on the number of RBCs and PCs transfused, percent products leukoreduced, and rate of FNHTR and ATR from 1995 through December 2002. After dividing this time period into three phases (SLR, transition, and UPL), these data were evaluated using odds ratio (ORs) and Student's t tests. RESULTS: A total of 145,369 RBCs and 137,982 PCs (29,487 PC pools) transfused between January 1995 and December 2002 were evaluated. For RBCs, the relative FNHTR rate decreased 47.1 percent, from 0.34 percent (SLR) to 0.18 percent (UPL) (p < 0.0001). ATR rates for RBCs showed 0.09 percent for both SLR and UPL groups (p > 0.05, NS). For PCs, the FNHTR relative rate decreased 93.1 percent, from 2.18 percent for SLR to 0.15 percent for UPL (p < 0.0001). Rates for ATR were 0.49 percent (SLR) and 0.35 percent (UPL) (p > 0.05, NS). CONCLUSIONS: A significant decrease in the frequency of posttransfusion FNHTR, but not ATR, for RBCs and PCs followed introduction of 100-percent UPL. The data support the hypothesis that the practice of UPL of RBCs and PCs decreases the frequency of FNHTR and thus improves patient care over the practice of selective leukoreduction.     

Characterization of reactions after transfusion of cellular blood components that are white cell reduced before storage

Background: During the storage of cellular components before transfusion, cytokines that may mediate transfusion reactions are released from white cells (WBCs). Adverse effects of transfused cellular blood components therefore depend not only on the number of residual WBCs in blood components, but also on the timing of WBC reduction. Study Design and Methods: Febrile nonhemolytic transfusion reactions (FNHTRs), allergic reactions, and other reactions were characterized in recipients of 4728 units of red cells (RBCs) and 3405 bags of single-donor apheresis platelets (SDAPs), all of which underwent prestorage WBC reduction. To delineate the impact of prestorage versus poststorage WBC reduction of RBCs on transfusion reactions, these results were compared with reactions occurring after the transfusion to similar recipients of 6447 bags of RBCs that underwent poststorage WBC reduction by bedside filtration and 5197 units of SDAPs that underwent prestorage WBC reduction. The levels of interleukin (IL) 1 beta, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured in a subset of 20 implicated cellular blood components at the time of transfusion reactions and correlated with the duration of storage before transfusion. Results: The incidence of reactions was greater after transfusions of SDAPs (5.49%) than of RBCs (1.63%). The incidence of FNHTRs after transfusion of RBCs that were WBC reduced before storage (1.1%) was significantly lower (p = 0.0045) than that after transfusion of RBCs that were WBC reduced after storage (2.15%). Although allergic reactions to RBCs that were WBC reduced before storage were also less common (0.41%) than those to RBCs that were WBC reduced after storage (0.51%), the difference was not significant (p = 0.067). At the time of reactions to RBCs and SDAPs that were reduced before storage, the level of IL-6 was negatively correlated (r = -0.54, p = 0.014) with the duration of storage before transfusion, and there was no correlation between the level of either IL-1 beta or IL-8 and the interval before transfusion. TNF-alpha was not detectable in any implicated component. Conclusion: FNHTRs, but not allergic reactions, were less common after transfusion of RBCs that were WBC reduced before storage than after the transfusion of those WBC reduced after storage at the bedside by filtration. The level of IL-6 in implicated cellular blood components that were WBC reduced before storage was inversely correlated with the length of storage before transfusion. Further studies are needed to determine whether the transfusion of cellular blood components that were WBC reduced before storage can both diminish the incidence of adverse reactions and improve outcome.     

Universal leukoreduction decreases the incidence of febrile nonhemolytic transfusion reactions to RBCs

BACKGROUND: Febrile nonhemolytic transfusion reactions (FNHTR) is a relatively common complication associated with allogeneic transfusion. Because WBCs have been implicated in the mechanism of FNHTRs, it has been proposed that the transfusion of leukoreduced RBCs should be associated with a decreased incidence of FNHTRs. These reactions are generally not life threatening, but they are expensive in their management, evaluation, and associated blood‐product wastage. Over the past several years, the proportion of leukoreduced RBCs has increased at Johns Hopkins Hospital in an effort to move toward complete leuko‐reduction. A retrospective analysis is reported here of FNHTRs in RBC recipients as the inventory increased in percentage of leukoreduced RBC units. STUDY DESIGN AND METHODS: Between July 1994 and December 2001, all transfusion reactions (TRs) associated with the transfusion of allogeneic RBCs were retrospectively analyzed. Both computerized data and individual TR reports were reviewed. Patients who had both allergic and febrile features were included as part of both categories. TRs were reported as a percentage of total units transfused. Two time periods were selected for direct comparison. July to December 1994 represents the time period before the initiation of an increase in leuko‐reduction. July to December 2001 represents a time period when almost complete leukoreduction (99.5%) had been achieved. The TR data were compared between these two time periods, comparing a time before leuko‐reduction to a time period after leukoreduction had been achieved. The trends in TRs over the entire 7.5‐year period of July 1994 to December 2001 were also assessed. RESULTS: In the initial period before the initiative to move toward leukoreduction, 96 percent of our RBC inventory was non‐leukoreduced. In the study period after leukoreduction, 99.5 percent of our RBC inventory was leukoreduced. When comparing these two time periods, the incidence of FNHTRs decreased from 0.37 percent to 0.19 percent (p = 0.0008). The trend over the entire 7.5‐year study period confirms the decrease in FNHTRs as the percentage of leukoreduced RBCs increased. The incidence of allergic TRs has remained unchanged over this time period. CONCLUSIONS: As our institution has increased its inventory of leukoreduced RBCs to approximately 100 percent, selective leukoreduced protocols have been discontinued. The incidence of FNHTRs has decreased significantly and the rate of allergic reactions has essentially remained unchanged. Leukoreduction is effective in decreasing FNHTRs associated with the transfusion of allogeneic RBCs.     

去白细胞输血预防非溶血性发热性输血反应的临床应用分析

评价临床输注去白细胞的红细胞悬液和浓缩血小板悬液预防非溶血性发热性输血反应（FNHTR）的效果。选择100例肝硬化，胃溃疡和胃癌等病人输注去白细胞的红细胞悬液，对照组相类似50例病人输注普通红细胞悬液。240例急性或慢性白血病，再生障碍性贫血，多发性骨髓瘤，血小板减少性紫癜，糖尿病，肝硬化，上消化道出血，重症肝炎，烧伤癌症放，化疗等患者分为两组，各组120例随机接受去白细胞的血小板或未去白细胞的血小板悬液，观察FNHTR的发生率，结果表明，在100例接受去白细胞的红细胞悬液的患者中未发生FNHTR，对照组50例患者中有8例发生FNHTR，发生率为16%；输注血小板的患者中，去白细胞和未去白细胞的FNHTR发生7例和25例，发生率分别为5.83%和20.83%。结论：去白细胞输血可防止或减少FNHTR的发生。     

The effect of prestorage WBC reduction on the rates of febrile nonhemolytic transfusion reactions to platelet concentrates and RBC

BACKGROUND: Febrile non-hemolytic transfusion reactions (FNHTRs) are a common complication of platelet concentrate (PC) and RBC transfusions, usually ascribed to cytokines released by WBCs and perhaps the platelets themselves during storage. Prestorage WBC reduction should abrogate the accumulation of these cytokines reducing the number of FNHTRs. STUDY DESIGN AND METHODS: A retrospective analysis of FNHTR to PCs and RBCs before universal WBC reduction (PrUR) (July 1997-January 1998 for PCs, July 1997-July 1999 for RBCs) and after its introduction (PoUR) (February 1998-August 2001 for PC, August 1999-August 2001 for RBCs) was undertaken. All transfusion reactions were stratified based on component and date of reaction. Other adverse transfusion reactions were grouped into three periods: July 1997-January 1998, February 1998-July 1999, and August 1999-August 2001. A chi-square test was performed to determine the significance of the differences between groups. RESULTS: In the PRUR group, there were: 231 FNHTRs in 70,396 RBC units transfused (0.33%) and 29 FNHTRs in 6502 PC units transfused (0.45% percent). In the PoUR group, there were 136 FNHTRs in 72,949 RBC units transfused (0.19%, p < 0.001) and 56 FNHTRs in 50,555 PC units transfused (0.11%, p < 0.001). Of the other adverse events, only TRALI reactions were significantly reduced. CONCLUSION: Prestorage WBC reduction significantly reduced the rate of FNHTRs to PCs and RBCs.     

保存前滤除白细胞对预防FNHTR及改善红细胞变形能力的作用

目的探讨推广血站型滤器的应用效果。方法将悬浮红细胞分为过滤组和对照组,在保存前和保存期检测5种细胞因子的水平及红细胞变形指数（EI）;临床输血患者按所输去白细胞悬浮红细胞过滤前保存时间分为5组,分别为0d、≤7d、≤14d、≤21d和〉21d,观察各组FNHTR发生率。结果对照组细胞因子随保存时间的延长而在血液中不断积累,过滤组细胞因子在保存中维持在原有的较低水平;在保存后期过滤组EI明显高于对照组;FNHTR发生率与过滤前保存时间呈正相关（P〈0．01）。结论在悬浮红细胞保存中存在多种细胞因子的产生和累积,而去白细胞过滤可在一定程度上抑制这一效应;保存前滤除白细胞可以有效预防FNHTR的发生,故悬浮红细胞应在保存前滤除白细胞。     

Removal of white cells from red cells by transfusion through a new filter

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 × 10(6) and less than or equal to 2.5 × 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.     

Hemotherapy bedside biovigilance involving vital sign values and characteristics of patients with suspected transfusion reactions associated with fluid challenges: can some cases of transfusion‐associated circulatory overload have proinflammatory aspects?

BACKGROUND: Monitoring of patients' vital sign values (VSVs) during hemotherapy may have an important role in the recognition and mitigation of transfusion‐associated circulatory overload (TACO). Knowledge regarding VSVs and other patient characteristics in bedside‐reported TACO or fluid challenge–suspected transfusion reactions (TACO/FC‐STRs) is limited. STUDY DESIGN AND METHODS: We performed a retrospective observational cohort study of cases of uncomplicated red blood cell (RBC) transfusions (UCTs) and reported suspected transfusion reaction (STR) cases investigated by our hospital's transfusion medicine service (TMS) from January 1, 2005, to February 29, 2008, using data obtained from TMS consult reports and quality improvement databases examining VSVs and patient characteristics in TACO/FC‐STRs. RESULTS: The frequency of TACO/FC‐STRs was 0.19% per all RBC units transfused (1:530 units transfused). Both clinically and statistically (p ≤ 0.05) significant changes were encountered in all VSVs in patients experiencing TACO/FC‐STRs either at the 15‐minute time interval or at the end‐of‐transfusion time points. Measured and derived VSVs related to the patients' blood pressure in the peritransfusion period were consistently increased. Approximately two‐thirds of TACO/FC‐STR patients also exhibited inflammatory related signs and symptoms at STR bedside presentation. Differences (all p ≤ 0.050) between UCT and TACO/FC‐STR cohorts were seen for patient mean weights (80 kg vs. 72 kg), mean minutes to transfusion completion (121 min vs. 83 min), and mean storage age of suspected sentinel RBC unit (22.5 days vs. 25.2 days). CONCLUSION: Trend monitoring of peritransfusion VSVs, especially blood pressures, may aid in the bedside recognition of TACO/FC‐STRs. A subset of these patients may also present with febrile and/or inflammatory signs and symptoms.     

Red blood cell use outside the operating theater: a prospective observational study with modeling of potential blood conservation during severe blood shortages

BACKGROUND: National guidance recommends planning for future blood shortages, but few studies have evaluated how reduced demand could be achieved acutely.
STUDY DESIGN AND METHODS: A trained observer collected data concerning red blood cell (RBC) transfusion events outside the operating theater during 68 hours of blood bank monitoring over 7 weeks. Data were gathered at the patients' bedside from clinical staff and charts. Transfusions were classified according to the presence of bleeding and medical specialty (medical, surgical, other). Hemoglobin (Hb) transfusion triggers, RBCs transfused, and posttransfusion Hb values were collected. Evidence-based scenarios were used to model the potential RBC savings that could be achieved if acute shortages occurred, incorporating ischemic heart disease as a potential decision modifier.
RESULTS: A total of 83 patients received 100 transfusion events, comprising 207 RBC units, during the sampling periods. The relative use of RBC units across specialties was as follows: medical, 74%; surgical, 22%; and other, 4%. For medical and surgical patients, respectively, 31 and 10% of all RBC units were transfused for anemia without evidence of bleeding, and 38 and 12% were transfused for non–life-threatening bleeding. Eight-five percent of all patients who received transfusions had stable vital signs before transfusion. Our model suggested that only 11% of RBCs would be conserved by cancellation of major surgery, whereas 23% to 47% of all RBCs could be conserved by controlling transfusions to medical patients.
CONCLUSION: In institutions with patterns of blood use similar to ours, control of transfusions to medical patients is the most effective response to acute blood shortages.     

Failure of bedside ABO testing is still the most common cause of incorrect blood transfusion in the Barcode era.

BACKGROUND AND OBJECTIVES. ABO-incompatible red blood cell (RBC) transfusions are a major risk in transfusion medicine. Identification of factors leading to this hazard is important to improve transfusion safety. MATERIAL AND METHODS. All consecutive erroneous ABO-incompatible transfusions occurring from January 1997 to December 2004 at the Charité University Hospital in Berlin, Germany were analysed. RESULTS. A total of 343,432 RBC units were transfused, and eight patients erroneously received 13 ABO-incompatible RBC concentrates. The most frequent error was incorrect bedside testing (n=7). Intensive care treatment was required in two cases, but there were no fatal mistransfusions. Four patients had no or only mild reactions. CONCLUSION. Mistransfusions are still a considerable risk in transfusion medicine despite quality control systems and electronic data processing. An increase in transfusion safety may require the introduction of further systems, e.g. radio-frequency identification (RFID) tags.     

A multistate cluster of red blood cell transfusion reactions associated with use of a leucocyte reduction filter

In 2000, the American Red Cross (ARC) received reports of unusual transfusion reactions of unknown aetiology among patients receiving leucocyte-reduced (LR) red blood cell (RBC) units in multiple distribution regions. We evaluated potential risk factors of reactions among patients who received LR-RBC transfusions. A case-patient was defined as any patient with onset of back pain while receiving an LR-RBC transfusion from 1 January to 25 May 2000. Controls were chosen randomly and selected in a 1:3 case : control ratio from healthcare facilities in which case-patients were transfused. Product-specific risk factors of reactions were further determined through nested case-control study, procedural review of blood collection facility and quality-control-testing record review of product processing. Reaction incidence rates were determined through ARC blood product distribution data by region of blood collection and processing. There were 29 reactions detected in patients who received transfusions in 13 healthcare facilities in five states. Eighteen case-patients and 78 controls were included in the case-control study. In univariate analysis, case-patients were more likely than controls to have a haematologic malignancy, to have received the transfusion as an outpatient, to have received an RBC transfusion within the previous 3 months, to have received medication used to prevent reactions or to diminish their intensity upon transfusion (i.e. premedication) or to have received LR-RBC units prepared with the HemaSure r\LS System(HS) rather than two other filters used. In multivariate analysis limited to recipients of HS-filtered RBC units, transfusion premedication [adjusted odds ratio (AOR) = 7; 95% confidence interval (CI) 1.4-37; P = 0.02] and transfusion as an outpatient (AOR = 5; 95% CI 1.1-20; P = 0.03) were independently associated with reactions. The rate of reported transfusion reactions was 2.0 reactions per 10 000 RBC units distributed. A multistate cluster of transfusion reactions was significantly associated with leucocyte filtration of RBC units prepared with a specific product, the HS filter. The reactions also were independently associated with premedication and transfusion as an outpatient; these may be surrogates for an increased risk of reaction or for greater likelihood of detection. The mechanism for these reactions has not been elucidated. This cluster of reactions underscores the importance of surveillance efforts to detect adverse events after transfusion, particularly when new methods to modify blood products are introduced.     

Acute and delayed hemolytic transfusion reactions secondary to HLA alloimmunization

BACKGROUND: HLA antibodies may be directed against HLA antigens on RBCs, but these antibodies are generally not considered to be clinically significant in transfusion practice. A case of a multiparous woman who had hemolytic transfusion reactions due to HLA-related Bg antibodies is reported. CASE REPORT: A 37-year-old woman was admitted with anemia. No unexpected RBC antibodies were identified. Two group O, D+ RBC units were transfused. Ten days later she returned with hemolysis and anemia. Two more RBC units were ordered, no unexpected RBC antibodies were identified, and two crossmatch-compatible units were issued. During the transfusion, the patient developed symptoms of an acute reaction, and the posttransfusion sample showed evidence of intravascular hemolysis. RESULTS: Repeat RBC antibody screen showed anti-Bg. HLA antibody screen identified anti-HLA-A2, A28, B7, B7 cross-reactive group (CREG). The two RBC units from the first transfusion episode and one RBC unit from the second transfusion episode were HLA incompatible with the patient. No other cause for the hemolytic reactions was identified. The patient was later successfully transfused with one RBC unit from an HLA-compatible donor. CONCLUSION: HLA antibodies should be considered in patients with hemolytic transfusion reactions when RBC-specific antibodies are not found to be the etiology.     

Evaluation of Transfusion Practices in Noncardiac Surgeries at High Risk for Red Blood Cell Transfusion: A Retrospective Cohort Study

Perioperative bleeding is a major indication for red blood cell (RBC) transfusion, yet transfusion data in many major noncardiac surgeries are lacking and do not reflect recent blood conservation efforts. We aim to describe transfusion practices in noncardiac surgeries at high risk for RBC transfusion. We completed a retrospective cohort study to evaluate adult patients undergoing major noncardiac surgery at 5 Canadian hospitals between January 2014 and December 2016. We used Canadian Classification of Health Interventions procedure codes within the Discharge Abstract Database, which we linked to transfusion and laboratory databases. We studied all patients undergoing a major noncardiac surgery at ≥5% risk of perioperative RBC transfusion. For each surgery, we characterized the percentage of patients exposed to an RBC transfusion, the mean/median number of RBC units transfused, and platelet and plasma exposure. We identified 85 noncardiac surgeries with an RBC transfusion rate ≥5%, representing 25,607 patient admissions. The baseline RBC transfusion rate was 16%, ranging from 5% to 49% among individual surgeries. Of those transfused, the median (Q1, Q3) number of RBCs transfused was 2 U (1, 3 U); 39% received 1 U RBC, 36% received 2 U RBC, and 8% were transfused ≥5 U RBC. Platelet and plasma transfusions were overall low. In the era of blood conservation, we described transfusion practices in major noncardiac surgeries at high risk for RBC transfusion, which has implications for patient consent, preoperative surgical planning, and blood bank inventory management.     

Number of RBC units and rate of transfusionto anemic HIV-positive patients assigned to receiveWBC-reduced or non-WBC-reduced RBCs: the viral activation transfusion study experience

BACKGROUND: It is known that the use of filtration to reduce WBCs in RBC units is associated with a 6- to 15-percent loss of RBCs. It is not known if the use of such WBC-reduced RBCs results in an increased need for RBC units or in the transfusion of more units per year to patients with anemia. STUDY DESIGN AND METHODS: In the multicenter Viral Activation Transfusion Study (VATS), anemic HIV-positive patients were randomly assigned to receive either WBC-reduced or non-WBC-reduced RBCs. The number of RBC units transfused per patient and the rate of RBC use were studied. All RBC units given after the enrollment transfusion were counted, until the end of follow-up or the occurrence of bleeding (receiving >5 RBCs within 2 consecutive days). RESULTS: As expected, the WBC-reduced RBC units in VATS were lighter in weight than the non-WBC-reduced units (median weight: WBC-reduced, 300 g; non-WBC-reduced, 330 g; p<0.0001). After the enrollment transfusion, 258 WBC-reduced arm patients received 1279 units of RBCs (average, 5.0 units/patient, median, 2 units) while 262 patients in the non-WBC-reduced arm received 1111 RBCs (4.2 units/patient; median, 2 units). The number of units transfused for anemia was slightly greater in the WBC-reduced arm, but the difference was not significant (p = 0.41). Similarly, the rate of RBC use was somewhat higher in the WBC-reduced arm, but the difference was not significant (p = 0.14). The median was 2.3 units per patient per year of follow-up in the WBC-reduced arm; the median in the non-WBC-reduced arm was 1.2 units. CONCLUSION: This study confirms that WBC-reduced RBC units are significantly lighter in weight than non-WBC-reduced RBCs. However, in the setting of a large, randomized, blinded study of transfusion for anemia, the smaller size of the WBC-reduced RBC units had no significant effect on the number of RBC units transfused or on the rate at which RBC units were used. In this study, the frequency of blood transfusion may have had a greater relationship to the frequency of routine, scheduled appointments or transfusion orders for a specified Hb trigger than to the actual Hb content of the unit.     

Storage time of transfused red blood cells and impact on clinical outcomes in hematopoietic stem cell transplantation

BACKGROUND: Red blood cell (RBC) transfusion may prolong recovery in some patients, perhaps due to changes that occur during more prolonged RBC storage. We examined the impact of RBC transfusion and the age of transfused RBC units on clinical outcomes in hematopoietic stem cell transplantation (HSCT). STUDY DESIGN AND METHODS: Data concerning RBC transfusions between Day 0 and Day +30 were analyzed for patients undergoing HSCT (n = 555) at a single institution. “Old” RBC units were defined as those stored for 15 days or longer. RESULTS: The proportion of old RBC units transfused and the mean age of transfused units did not correlate with 100‐day nonrelapse mortality, organ‐specific toxicity, length of stay (LOS), or incidence of intensive care unit (ICU) admission (p > 0.05). In comparing the 71 patients who received only old RBC units with 218 patients who received only “new” RBC units, there was no increase in adverse clinical outcomes after HSCT. Autologous transplant recipients (n = 355, 3.8 units/patient) were more likely to avoid RBC transfusion and received fewer units compared with allogeneic recipients (n = 200, 6.4 units/patient, p < 0.0001). The mean number of transfused RBC units was greater in patients admitted to the ICU (10.5 units vs. 3.7 units/patient, p < 0.01), correlated with longer LOS (p < 0.0001), and correlated with increasing number of organ systems with toxicity of at least Grade 2 (p < 0.0001). CONCLUSION: The importance of RBC storage time does not appear to influence clinical outcomes in HSCT. Patients with increased RBC transfusion requirements have greater toxicity after HSCT. Whether RBC transfusion contributes to toxicity, however, remains unclear.     

Universal leucodepletion: an overview of some unresolved issues and the highlights of lessons learned.

Universal leucodepletion (ULD) has been introduced in several countries based on the evidence that selective leucodepletion improves the clinical safety of blood components and based on animal studies that TSE infectivity is 5-7 times higher in the buffy coat than in plasma. Therefore it is perceivable that the removal of the buffy coat, by filtration, removing both leucocytes and platelets, may prove beneficial in reducing the potential risk of transmission of variant CJD by blood components.The implementation of a ULD policy has created some new requirements: Validation/standardisation of various leucodepletion processes to ensure compliance with set specifications. Standardisation/harmonisation of sampling and low leucocyte counting technologies to ensure the interchangeability of results nationally. The establishment of external quality assessment schemes on 'real' leucodepleted products where the cells come in contact with the filter matrix, to monitor the low leucocyte counting performance, nationally. Assessment of filtration-induced generation/retention of major biological response modifiers (BRM), having potential for the development of transfusion reactions. Using these approaches we have identified that, while the overall leucodepletion performance has improved following harmonisation/standardisation of the operational and counting technologies, there are still some unresolved problems and ULD alone may not provide complete protection from some viral transmission such as HTLV and CMV infections or reduction of bacterial sepsis and generation of some BRM. Moreover, ULD has not fully abrogated febrile non-haemolytic transfusion reactions (FNHTR). Therefore the key issue is not the 3-4 log(10) reduction of residual leucocytes but the design of new generation filters or leucodepletion processes with better performance characteristics, to further reduce some specific leucocyte subsets and their fragments as well as reduce the activation of coagulation/complement/kinin and inflammatory systems. Efforts should also be made to reduce the rapid development of apoptotic/necrotic cells and the residual risk associated with plasma, which often contains a vast array of BRM, responsible for residual transfusion reactions. These could only be effectively achieved by working in cooperation with the suppliers of blood component technologies.This overview briefly highlights some of the unresolved issues related to ULD, based on the experience in the UK. Technical details can be found in the reading list provided at the end.     

Characterization of reactions after exclusive transfusion of white cell- reduced cellular blood components

BACKGROUND: Potential adverse effects of white cells (WBCs) within transfused cellular blood components include febrile nonhemolytic transfusion reactions (FNHTRs), alloimmunization, transmission of infectious diseases, transfusion-related acute lung injury, and immunomodulation. Although exclusive use of WBC-reduced components to prevent alloimmunization and cytomegalovirus transmission has been studied, the use of these components to avert FNHTR has not been examined. STUDY DESIGN AND METHODS: Transfusion reactions (FNHTRs, allergic reactions, and others) were characterized in recipients of 12,277 WBC-reduced single-donor apheresis platelets (SDAPs) and/or red cells (RBCs). Medical and laboratory evaluations for possible infectious and immunologic (alloimmunization) causes of each reaction were undertaken, and the benefit of further modification of components for the prevention of subsequent reactions was also evaluated. RESULTS: Transfusion reactions occurred after 481 (3.92%) of 12,277 transfusions. Allergic reactions occurred more commonly after transfusion of SDAPs (3.69%) than of RBCs (0.51%). Conversely, FNHTRs occurred more commonly after transfusion of RBCs (2.15%) than of SDAPs (1.58%). HLA antibodies were present in a posttransfusion sample from 27 (10.6%) of 255 patients; bacterial contamination was a possible cause of only 2 (0.42%) of 481 reactions. In patients with recurrent FNHTRs, further WBC reduction in components did not wholly prevent further FNHTRs. CONCLUSION: The incidence of FNHTRs and alloimmunization after exclusive transfusion of WBC-reduced RBCs and SDAPs was low. Further WBC reduction in components transfused to patients with a history of recurrent FNHTRs does not completely prevent subsequent reactions.     

A lack of serologic evidence of transmission of Chlamydia pneumoniae by transfusion of buffy coat-depleted RBCs

BACKGROUND: Recent studies have shown that a high percentage of blood donors harbor Chlamydia pneumoniae DNA and antigens within their PBMNCs. The aim of the present study was to investigate whether recipients of RBC transfusions who were seronegative for C. pneumoniae before transfusion showed any evidence of seroconversion after transfusion. STUDY DESIGN AND METHODS: Patients who were possible recipients of RBC transfusion and negative in a screen test for IgG antibodies against C. pneumoniae at the time of blood group determination were candidates to be included in the study. The patients were contacted 3.0 to 3.5 months after the blood group determination, and those who accepted to participate agreed that another venous blood sample could be taken. RESULTS: Among the patients who participated, 53 had become recipients of RBC transfusion (transfused group), and 51 later did not receive any RBC transfusion (control group). No significant change was found in IgG titer against C. pneumoniae between the first and the second sample from the same patient, in either the transfused group or the control group. CONCLUSION: In our study, which was limited to 53 seronegative recipients of RBC units from seropositive donors, we found no serologic evidence that C. pneumoniae could be transmitted by RBC transfusion.     

输血对脑外伤患者术后感染的影响

目的 探讨输血对脑外伤患者术后感染的影响,指导合理输血。方法 选择本院1997年1月~2004年1月525例脑外伤手术患者,其中225例术中输注普通悬浮红细胞,202例输注悬浮去白细胞红细胞,98例未输血。对3组患者术后感染率及输血剂量与感染率的关系进行比较。结果 普通悬浮红细胞输血组术后感染率为11．11％,悬浮去白细胞红细胞输血组术后感染率为3．46％,与普通悬浮红细胞输血组相比差异有显著性（P〈0．01）,与未输血组感染率（2．04％）比较差异无显著性。普通悬浮红细胞输血组患者的输血量与术后感染的发生显著相关（P〈0．01）,而悬浮去白细胞红细胞输血组的输血量与术后感染率的相关性不显著。结论 脑外伤患者术后感染的发生与输血、血液成分及输血量等有关。在保证患者能够耐受手术的情况下,应尽量不输血或少输血,对确需输血的患者,应该输注去白细胞红细胞。