Factors that influence platelet recovery after transfusion: resolving donor quality from ABO compatibility

BACKGROUND: A system was established to examine the extent to which the apheresis donor determines platelet recovery after transfusion, to measure the impact of ABO identity, and to predict outcome by evaluating the donor. STUDY DESIGN AND METHODS: The percentage of platelet recovery was measured after prophylactic transfusion of apheresis units divided from single donors to paired recipients with uncomplicated thrombocytopenia secondary to leukemia chemotherapy. Platelet microaggregation induced by citrate was measured at the time of apheresis. RESULTS: Platelet recoveries in paired recipients correlated strongly when both transfusions were ABO- identical. When one recipient was ABO-identical and the other was ABO-nonidentical, nonidentical transfusions yielded one-third the recovery of ABO-identical transfusions. In ABO-identical transfusions, platelet recovery in donors having microaggregates in the before-apheresis ACD sample was one-third that in donors without microaggregates. This difference was observed at 1 and 24 hours. Expression of P-selectin in the apheresis units at the time of transfusion correlated well with ACD microaggregates in the before-apheresis sample. CONCLUSION: When transfusions of platelets are ABO-identical, donor quality dominates recovery in circulation. Donor quality is predicted by a rapid and simple assay of citrate-induced microaggregation performed at the time of apheresis. When donor quality is factored out, ABO identity prevails.     

Evaluation of changes in hemoglobin levels associated with ABO- incompatible plasma in apheresis platelets

BACKGROUND: Hemolytic transfusion reaction is considered a rare complication of platelet transfusion. If minor ABO incompatibility exists (donor antibody directed against recipient's red cells [plasma- incompatible platelets]), however, the antibodies present in the plasma of platelets may cause acute hemolysis. A retrospective study was performed to identify possible hemolysis related to the transfusion of plasma-incompatible apheresis platelets. STUDY DESIGN AND METHODS: Acute hemolysis due to low-titer anti-A present in group O apheresis platelets transfused to a group A patient is reported. Pretransfusion and posttransfusion hemoglobin levels were evaluated in 16 non-group O autologous bone marrow transplant patients receiving apheresis platelets. All patients received, within 24 hours, both ABO-identical and plasma-incompatible platelet transfusions. No red cells were transfused during the time between the collection of the pretransfusion and posttransfusion hemoglobin samples. RESULTS: A total of 24 evaluable paired platelet transfusions in the 16 patients were compared. The mean change in hemoglobin following transfusion of the ABO-identical and plasma-incompatible platelets was -0.50 g per dL and - 0.11 g per dL, respectively (p = 0.193). CONCLUSION: There was no significant change in the hemoglobin concentration associated with the transfusion of plasma-incompatible apheresis platelets (minor ABO incompatibility) in our study group. The case reported here represents the only hemolytic transfusion reaction identified among 46,176 platelet transfusions performed at this hospital, despite approximately 21 percent of all platelet transfusions being plasma incompatible. The risk of such a reaction remains low.     

Transfusion of ABO-nonidentical platelets is not associated with adverse clinical outcomes in cardiovascular surgery patients

BACKGROUND: Current blood transfusion standards in Canada and the United States permit transfusion of ABO-nonidentical platelets when ABO-identical platelets are not available. This practice increases the availability of platelets, a component in chronic shortage in Ontario, Canada because of the 5-day shelf-life. The impact of transfusing ABO-nonidentical platelets on patient outcomes is unknown. STUDY DESIGN AND METHODS. A retrospective review of 1721 patients who had cardiovascular surgery between November 1989 and December 1999 and who had also received a platelet transfusion perioperatively was conducted. The impact of platelet and plasma incompatibility on clinical outcomes was analyzed. RESULTS: The analysis included 1691 patients who were divided into two groups according to the compatibility of the first platelet transfusion received: ABO-identical platelet transfusion (n = 1008) and ABO-nonidentical platelet transfusion (n = 683). The only difference in baseline characteristics between the two groups was that there were more urgent cases in the ABO-identical platelet transfusion group (p = 0.04). There were no significant differences in mortality at 30 days (10% for both groups, p = NS) or in postoperative length of stay (median, 7.0 days for both groups, p = NS). No significant differences were found with respect to the use of blood components, indices of bleeding, incidence of infection, or platelet CCIs. CONCLUSION: Transfusion of ABO-nonidentical platelets in patients undergoing cardiovascular surgery is not associated with an adverse impact on patient outcome.     

Release of biologically active CD154 during collection and storage of platelet concentrates prepared for transfusion

Summary. Background: Millions of platelet transfusions are given each year. Transfusion reactions occur in as many as 30% of patients receiving unmodified platelet transfusions. The cause of some transfusion reactions remains unclear. The current paradigm suggests that platelet concentrates (PC) contain proinflammatory mediators that are released by white blood cells during collection, processing and storage. CD154 (CD40 ligand, CD40L) is a potent inflammatory mediator, normally sequestered inside the resting platelet, that is known to translocate to the platelet membrane and be shed into plasma in response to agonist activation. We hypothesized that platelet‐soluble CD154 (sCD154) is ‘spontaneously’ released by transfused platelets and plays a major role in transfusion reactions. Objectives: To determine the time course and biological properties of CD154 translocation and release during collection and storage of platelets for transfusion. Methods: We measured surface and sCD154 in platelets prepared by the platelet‐rich plasma method or apheresis by fluorescence‐activated cell sorting and enzyme‐linked immunosorbent assay, respectively. The specific biological activity of platelet sCD154 was assayed by stimulation of the CD154/CD40 pathway in known CD40‐positive cells with PC‐derived supernatants. Results and conclusions: We demonstrate that PCs prepared for transfusion have high levels of membrane‐bound CD154 and sCD154, with maximum levels being seen 72 h after platelet collection. Importantly, we show that platelet‐derived sCD154 potently stimulates CD40‐positive cells. We propose that platelet‐derived CD154 is a key ‘cytokine’ responsible for adverse reactions associated with platelet transfusions. Improved methods of platelet collection and/or storage, which limit CD154 expression, could reduce the risks of transfusion reaction.     

Reactions Induced by Platelet Transfusions

SUMMARY: Platelet transfusions play a central role in therapeutic regimens for patients with hematologic/oncologic diseases who develop severe thrombocytopenia either in the course of their disease or following cytostatic therapy. Like other blood components, platelet transfusions have achieved a high degree of safety as far as transmission of viral diseases is concerned. However, transfusion of platelet concentrates is accompanied by a high frequency of febrile and anaphylactoid reactions. In rare cases, recipients of platelet concentrates are threatened by severe reactions as septic complications due to bacterial contamination of platelet concentrates, transfusion-related acute lung injury and severe anaphylactic episodes.     

10 Years Experience with Bacterial Screening of Platelet Concentrates in the Netherlands

SUMMARY: BACKGROUND: Contamination of platelets with bacteria is the major microbiological risk of blood transfusion. Screening for bacterial contamination can reduce the frequency of bacterial transmission considerably. In the present paper, the results of 10-year screening in the Netherlands are described. METHODS: All platelet concentrates were cultured with the BacT/Alert culturing system with large volume (7.5 ml) cultures in either an aerobic or an anaerobic bottle. Products were released on a 'negative-to-date' basis. RESULTS: After introduction of the diversion of the first milliliters of collected blood, the number of positive screening cultures decreased significantly from 0.85% to 0.37%. The frequency of transfusion-transmitted bacterial infections by platelet concentrates is currently less than 1 per 2 years in the Netherlands. CONCLUSION: Over a period of 10 years the bacterial screening system for platelet concentrates proved to result in a safe system with respect to microbiological infection as a result of platelet transfusions.     

ABO-identical versus nonidentical platelet transfusion: a systematic review

BACKGROUND: The significance of ABO matching for platelet (PLT) transfusion has not been clearly defined. The primary objective of this report is to assess whether ABO-identical PLT transfusion is associated with improved mortality and/or morbidity for patients with hematologic/oncologic disorders.
STUDY DESIGN AND METHODS: A systematic review to January 2009 was conducted. Data on mortality, morbidity, PLT refractoriness, and PLT increment after transfusion were abstracted.
RESULTS: A total of 100 citations were identified. Nineteen studies were included in the systematic review. A total of 1502 patients from three randomized controlled trials and 16 observational studies were included. Survival, bleeding events, and transfusion reactions were only considered as secondary outcomes in the reports reviewed. The PLT count increment was the primary outcome of several studies and was consistently higher with ABO-identical PLT transfusion. The largest difference in increment between ABO-identical and nonidentical PLT transfusion was 4 × 10⁹/L. No consistent benefit in clinical outcomes was noted. Survival was assessed in three reports with conflicting results. Although two studies described bleeding as an outcome, the assessment of hemorrhage was considered inadequate. In six studies, ABO-nonidentical PLT transfusion was not associated with transfusion reactions, and the results from four studies addressing the impact of ABO-identical PLT transfusion on PLT and red blood cell utilization were conflicting.
CONCLUSION: ABO-identical PLT transfusion results in a higher PLT increment. Randomized controlled trials are required to definitely determine the effect of ABO-identical PLT transfusion on survival, bleeding events, or transfusion reactions.     

Pediatric red cell and platelet transfusions

The aim of pediatric transfusions should be based on the concept of avoiding unnecessary transfusions without jeopardizing the patient safety and providing correct blood components when there are well founded indications to transfuse. Despite considerable efforts from transfusion services to increase transfusion safety, transfusions are still associated with preventable and unpreventable adverse effects that may, in the worst case, have severe and fatal consequences. Transfusions to pediatric patients constitute a small proportion of all transfusions but have higher incidence of adverse events compared to adults. Pediatric transfusions consist of intrauterine transfusions, top-up transfusions to neonates and young children, exchange transfusions in the management of hemolytic disease of newborn (HDN), in addition to sickle cell crisis, chronic transfusion therapy in thalassemia patients, massive transfusion in trauma, HLA- and HPA-compatible platelets in immunized patients and neonates with fetal neonatal alloimmune thrombocytopenia (FNAIT). Packed red cells (PRCs) and platelet (PLT) concentrates are the most utilized blood components and will be reviewed here.     

French Haemovigilance Data on Platelet Transfusion

Summary

The Agence Française de Securite Sanitaire des Produits de Santé (Afssaps; French Health Products Safety Agency) is responsible, through its hemovigilance unit, for the organization and the functioning of the national hemovigilance network. In accordance with the French law, it receives all data on adverse transfusion reactions regardless of their severity. With the aim of evaluating the tolerance of two kinds of labile blood products (LBP), pooled platelet concentrates (PP) and apheresis platelet concentrates (APC), we screened the French national database from January 1, 2000 to December 31, 2006. We observed that the number of transfusion incident reports is more than twice as high with APC (8.61:1,000 LBP) than with PP (4.21:1,000 LBP). The difference between these two ratios is statistically significant as shown by chi-square test (e = 21.00 with α = 5%). The risk to suffer adverse reactions of any type, except for alloimmunization, is higher with APC, and the major type of diagnosis related to APC is allergic reaction (1:200 APC issued) even if those allergic reactions are rarely serious. The new French National Hemovigilance Commission should impel a working group evaluating this topic and above all the impact of additive solutions which have been used since 2005 to put forward preventives measures.Key Words: French hemovigilance, Apheresis platelet concentratece, Pooled platelet concentrate, Adverse reaction     

The relationship between the duration of platelet storage and the development of transfusion reactions

BACKGROUND: The incidence of platelet transfusion reactions may depend partly on the length of storage. The influence of reactions on the effectiveness of platelet transfusions is not known. STUDY DESIGN AND METHODS: Platelet transfusion reactions, identified by prospective monitoring, were analyzed for the effects of component type, recipient lymphocytotoxic antibodies, bacterial contamination, and duration of storage. Posttransfusion corrected count increments (CCIs) were used to evaluate the effectiveness of transfusions associated with reactions by comparing them to those of randomly selected transfusions without reactions. RESULTS: Reactions accompanied 4 percent of the 4926 transfusions given and included 119 febrile nonhemolytic transfusion reactions, 62 allergic reactions, and 13 reactions with features of both. Platelet concentrates contained a mean of 0.5 × 10(8) white cells per unit. Lymphocytotoxic antibodies were detectable in 20 of 84 recipients tested proximate to a reaction. Bacterial cultures from 4 of 81 units were positive; 1 unit was associated with fatal Enterobacter sp. sepsis. The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions was related to platelet storage duration. The CCI was not significantly different for transfusions associated with reactions (10.97 [median, range 0–72.5; n = 165]) or not so associated (13.1 [median, range 0–39.5; n = 174]) (p = 0.08). CONCLUSION: The incidence of febrile nonhemolytic transfusion reactions but not allergic reactions appears to be related to the duration of platelet storage. Transfusion reactions may not have an adverse impact on the effectiveness of platelet transfusions.     

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。     

Collection and transfusion of blood and blood components in the United States, 1994

BACKGROUND: Collections and transfusions of blood in the United States in 1994 were measured and compared with those in 1992. STUDY DESIGN AND METHODS: Completed survey questionnaires were returned by all 147 regional blood centers, 1340 American Association of Blood Banks (AABB) member hospitals, and 523 non-AABB hospitals. Statistical tests verified the representativeness of the sample. RESULTS: The United States domestic blood supply in 1994 (13,340,000 units) was 3.3 percent less than in 1992. It included allogeneic blood (11,773,000 units), autologous blood (1,013,000 units), and directed donations (334,000 units). Of these, 432,000 units were rejected on testing, 11,107,000 units were transfused to 3,398,000 patients, and 1,801,000 units were discarded or unaccounted for. Platelet transfusions amounted to 7,866,000 units. Compared with the totals for 1992, transfusions of single-donor platelets (714,000 packs or 4,284,000 units) increased by 17.6 percent, while transfusions of platelet concentrates (3,582,000 units) fell by 23.6 percent. Fresh-frozen plasma transfusions (2,621,000 units) increased by 16.2 percent over the number for 1992. CONCLUSIONS: The US blood collection rate in 1994 was 74.6 units per 1000 population of donor age, the lowest recorded level since 1971. The US RBC transfusion rate in 1994 was 42.8 units per 1000 population, about the same as 1979. Transfusions of single-donor platelets, 16.5 units per 1000 population, exceeded transfusions of platelet concentrate (13.8/1000) for the first time. Plasma transfusions were 10.1 units per 1000 population. The US blood supply in 1994 was adequate to meet patient demands.     

Platelet transfusions in children: results of a randomized,prospective, crossover trial of plasma removal and a prospective audit of WBC reduction

BACKGROUND: Febrile nonhemolytic transfusion reactions (FNHTRs) complicate 2 to 37 percent of platelet transfusions in adults, but the incidence of such reactions in children is not known. The effectiveness of plasma reduction after storage and WBC reduction of platelet concentrates before storage was studied in pediatric recipients of platelet transfusions. STUDY DESIGN AND METHODS: In the first study, a prospective randomized crossover design was used in which patients received either unmodified whole-blood-derived or apheresis platelets or platelets from which most of the plasma supernatant had been removed just before transfusion. The second study was a prospective audit of recipients of prestorage WBC-reduced platelets. Children between 3 months and 17 years of age were eligible for both studies. Patients were assessed for signs and symptoms that are characteristic of a reaction during, immediately after, and 2 hours following transfusion. RESULTS: There were 226 platelet transfusions administered to 66 children. One hundred and sixty transfusions were given to 35 children enrolled in the randomized study, and 66 transfusions were given to 33 children during the audit. In the randomized study, nine of the 75 transfusions of unmodified platelets (12%) and six of 85 transfusions of poststorage plasma-removed platelets (7%) were associated with an FNHTR (p=0.42). In the audit, three of 66 transfusions of prestorage WBC-reduced platelets (5%) were associated with an FNHTR. Allergic reactions occurred with 5 percent (4 of 75), 6 percent (5 of 85), and 6 percent (4 of 66) of platelet transfusions, respectively. CONCLUSION: FNHTRs appear to be less common among pediatric recipients of platelet transfusions than in adults. In our two studies, there was a trend toward a lower frequency of FNHTRs with poststorage plasma removal and prestorage WBC reduction than with standard platelets, but this was not significant.     

Febrile and allergic transfusion reactions after the transfusion of white cell-poor platelet preparations

BACKGROUND: Nonhemolytic transfusion reactions (NHTRs) frequently occur after platelet transfusions. White cell (WBC)-derived inflammatory cytokines can cause these reactions, but they are rarely found in WBC-poor platelet preparations. Transfusion reactions were investigated with regard to the residual WBC content in the stored platelet concentrate in two consecutive study periods. STUDY DESIGN AND METHODS: In the first study period, platelet concentrates were WBC-reduced by bedside filtration. In the second period, all platelet concentrates were filtered before storage. Recipients who experienced transfusion reactions were examined with regard to their main clinical symptoms during and after transfusion. In the supernatant of the involved platelet concentrates, concentrations of interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor (TNF)alpha, macrophage inflammatory protein 1alpha, and RANTES were analyzed. RESULTS: The incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage WBC filtration (1.63% and 1.56%; p = 0.84). In both periods, NHTRs were predominantly of allergic origin. Inflammatory mediators IL-1beta, IL-6, IL-8, and TNFalpha were detectable in only a minority of platelet components involved in NHTRs. Platelet concentrates involved in allergic reactions contained high concentrations of RANTES (668 +/- 223 ng/mL). CONCLUSIONS: Prestorage WBC filtration did not reduce the incidence of these reactions, and inflammatory cytokines were of minor relevance. The proinflammatory platelet-derived chemokine RANTES, which accumulates even in WBC-reduced platelet concentrates, was associated with allergic transfusion reactions. Platelet-derived mediators may be a key to understanding NHTRs.     

Febrile and allergic transfusion reactions after the transfusion of white cell-poor platelet preparations

BACKGROUND: Nonhemolytic transfusion reactions (NHTRs) frequently occur after platelet transfusions. White cell (WBC)-derived inflammatory cytokines can cause these reactions, but they are rarely found in WBC-poor platelet preparations. Transfusion reactions were investigated with regard to the residual WBC content in the stored platelet concentrate in two consecutive study periods.
STUDY DESIGN AND METHODS: In the first study period, platelet concentrates were WBC-reduced by bedside filtration. In the second period, all platelet concentrates were filtered before storage. Recipients who experienced transfusion reactions were examined with regard to their main clinical symptoms during and after transfusion. In the supernatant of the involved platelet concentrates, concentrations of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)α, macrophage inflammatory protein 1α, and RANTES were analyzed.
RESULTS: The incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage WBC filtration (1.63% and 1.56%; p = 0.84). In both periods, NHTRs were predominantly of allergic origin. Inflammatory mediators IL-1β, IL-6, IL-8, and TNFα were detectable in only a minority of platelet components involved in NHTRs. Platelet concentrates involved in allergic reactions contained high concentrations of RANTES (668 ± 223 ng/mL).
CONCLUSIONS: Prestorage WBC filtration did not reduce the incidence of these reactions, and inflammatory cytokines were of minor relevance. The proinflammatory platelet-derived chemokine RANTES, which accumulates even in WBC-reduced platelet concentrates, was associated with allergic transfusion reactions. Platelet-derived mediators may be a key to understanding NHTRs.     

White blood cell inactivation after treatment with riboflavin and ultraviolet light

Functional white blood cells (WBCs) in blood components may be responsible for a number of adverse transfusion effects, including transfusion‐associated graft‐versus‐host disease (TA‐GVHD), alloimmunization, and alloimmune platelet (PLT) refractoriness. TA‐GVHD occurs when functional lymphocytes are transfused into a patient who is unable to mount an immune response to the human leukocyte antigen (HLA) due to HLA compatibility or immunosuppression. Alloantibodies against HLA antigens on donor WBCs and PLTs are the major cause of refractoriness to PLT transfusions in patients receiving repeated blood transfusions. Attempts to reduce these undesirable effects have included leukoreduction filters and gamma irradiation. Studies have shown that exposure of PLT concentrates to riboflavin and light (Mirasol pathogen reduction technology [PRT], CaridianBCT Biotechnologies) causes irreparable modifications of nucleic acids that result in inactivation of a wide range of pathogens as well as inhibition of the immunologic responses mediated by WBCs present in PLT concentrates. This article summarizes these studies and also reports on additional findings from the Trial to Reduce Alloimmunization to Platelets (TRAP) and Mirasol Clinical Evaluation (MIRACLE) trials. Data from in vitro studies and this clinical trial suggest that PRT treatment may be as effective as gamma irradiation in preventing TA‐GVHD and more effective than leukoreduction in preventing alloimmunization.     

Clinical factors influencing posttransfusion platelet increment in patients undergoing hematopoietic progenitor cell transplantation—a prospective analysis

BACKGROUND: Platelet transfusion refractoriness remains problematic in the management of patients who have undergone hematopoietic progenitor cell transplantation. Bone marrow transplantation itself is reported to be a relevant factor hampering efficient platelet transfusions. However, a prospective analysis assessing factors affecting platelet transfusion efficacy in the setting of hematopoietic progenitor cell transplantation has yet to be conducted. STUDY DESIGN AND METHODS: To identify factors independently influencing platelet transfusion efficacy after hematopoietic progenitor cell transplantation, a prospective study was performed to determine the effectiveness of platelet transfusions by estimating posttransfusion (16-hour) corrected count increments (CCI) in 42 consecutive patients (26 who received allogeneic transplants and 16 who received autologous transplants) with 439 available platelet transfusions. RESULTS: The mean CCI and percentage of CCI <4500 for all transfusions were 6161.1 +/− 7775.2 per microL and 42.1 percent, respectively. Multiple linear regression analyses revealed high total bilirubin, total body irradiation, high serum tacrolimus, and high serum cyclosporin A to be major factors independently predicting a lower CCI. HLA antibodies with restricted specificity and platelet antibodies were detected transiently in 17 and 14 percent of the patients, respectively. The presence of these antibodies was not, however, associated with a poor response to platelet transfusions. CONCLUSION: Platelet transfusion efficacy in hematopoietic progenitor cell transplant recipients is markedly influenced by clinical factors specific to the procedure as well as those already recognized in other settings. Alloimmunization is not, however, a major factor associated with a poor response to platelet transfusions after this procedure.     

Effects of in vitro adult platelet transfusions on neonatal hemostasis

Summary. Background: Thrombocytopenia is frequent among neonates, and 20–25% of affected infants are treated with platelet transfusions. These are frequently given for mild thrombocytopenia (platelets: 50–100 × 10⁹ L^?1), largely because of the known hyporeactivity of neonatal platelets. In tests of primary hemostasis, however, neonates have shorter bleeding and closure times (CTs) than adults. This has been attributed to their higher hematocrits, higher von Willebrand factor (VWF) concentrations, and predominance of longer VWF polymers. Objective: To determine whether the ‘transfusion’ of adult (relatively hyperreactive) platelets into neonatal blood results in a hypercoagulable profile. Methods: Cord blood (CB) and adult peripheral blood (PB) were separated (with a modified buffy coat method) to generate miniaturized platelet concentrates (PCs) and thrombocytopenic blood. PB‐derived and CB‐derived PCs (n = 7 per group) were then ‘transfused’in vitro into thrombocytopenic CB and PB. The effects of autologous vs. allogeneic (developmentally mismatched) ‘transfusions’ were evaluated with whole blood aggregometry, a platelet function analyzer (PFA‐100), and thromboelastography (TEG). Results: Adult platelets aggregated significantly better than neonatal platelets in response to thrombin receptor‐activating peptide, ADP, and collagen, regardless of the blood into which they were transfused. The ‘transfusion’ of adult platelets into thrombocytopenic CB resulted in shorter CTs‐EPI (PFA‐100) and higher clot strength and firmness (TEG) than ‘transfusion’ of neonatal autologous platelets. Conclusions: In vitro‘transfusion’ of adult platelets into neonatal blood results in shorter CTs than ‘transfusion’ with neonatal platelets. Our findings should raise awareness of the differences between the neonatal and adult hemostatic system and the potential ‘developmental mismatch’ associated with platelet transfusions for neonatal hemostasis.     

Blood collection and transfusion in the United States in 1997

BACKGROUND: Collections, processing, and transfusions of blood and blood components in the US in 1997 were measured and compared with 1994 and prior years. STUDY DESIGN AND METHODS: Questionnaires were returned by 2391 blood centers, AABB member hospitals, nonmember hospitals, and other facilities. Statistical procedures were used to verify that the sample was representative and to estimate national collections and utilization. RESULTS: The gross domestic blood supply in the US in 1997 was 12,602,000 units, 5.5 percent less than in 1994. It included 11,741,000 units of allogeneic community blood, 643,000 units of autologous blood, and 205,000 units of allogeneic-directed blood. Platelet transfusions amounted to 9,037,000 platelet concentrate equivalent units, of which 62.4 percent were apheresis packs. Compared with 1994, total platelet units transfused increased by 14.9 percent and single-donor platelet units transfused increased by 31.7 percent, whereas platelet concentrate transfusion declined by 3.8 percent. Transfusions of FFP increased by 26.6 percent compared with 1994. CONCLUSIONS: The margin of US allogeneic blood supply in excess of allogeneic transfusions in 1997 was 630,000 units, 5.4 percent of total allogeneic supply as compared with margins in prior years ranging between 9.3 and 10.9 percent. Although overall allogeneic available supply in 1994 was adequate to meet transfusion demand, the decrease in the margin between 1994 and 1997 is cause for concern. The rate of whole-blood collections in 1997 per 1000 members of the population aged 18 to 65 years was 12.6 percent lower than 1994. The RBC transfusion rate per 1000 members of the population in 1997 remained nearly the same as in 1994. However, the rates of platelet and of plasma transfusions both increased.     

A survey of Canadian neonatal blood transfusion practices

In 1990, the Pediatric Hemotherapy Committee of the American Association of Blood Banks developed and distributed a questionnaire addressing neonatal blood transfusion practices. The same questionnaire was subsequently sent to Canadian university-affiliated hospitals (n = 92). This report describes the results of the Canadian survey. Seventy-two percent (n = 66) of institutions contacted responded. Of these 42% (n = 28) had sufficient experience with neonatal transfusions and provided sufficient data for analysis. Although the majority of stated practices did follow published guidelines, several areas of variability and/or suboptimal practices were identified. With respect to component selection and preparation, suboptimal practices included excessive pretransfusion testing, unnecessary routine washing of RBC concentrates for small-volume transfusions, routine volume reduction of platelet concentrates and the use of suboptimal granulocyte preparations. With respect to transfusion practices, a disturbingly high percentage of respondents indicated that frozen plasma would be given in situations generally considered inappropriate. There was a great deal of variability in the provision of blood components at low risk for CMV, in the use of gamma irradiation and in the platelet count used for prophylactic platelet transfusions. The data collected in this survey provide information concerning practices that require improvement, identify areas where further research is desirable and provide a basis for comparison with current and future neonatal blood transfusion practices.