Patricia T. Pisciotto

Prophylactic versus therapeutic platelet transfusion practices in hematology and/or oncology patients

BACKGROUND: Platelet utilization has steadily increased throughout the past three decades. At the same time, there has been very little study of the current transfusion practices. STUDY DESIGN AND METHODS: A survey was conducted of institutional members of the American Association of Blood Banks (hospitals) that were actively involved in the care of pediatric and/or adult hematology and/or oncology patients. Inquiries were made relating to the extent of prophylactic versus therapeutic use of platelets, criteria used for prophylactic transfusion of platelets and type, and dose of platelets used. Data were analyzed according to patient age and type of hospital. RESULTS: Of 786 responding hospitals, 630 (80.2%) provided sufficient data for analysis; 126 of that 630 provided care for pediatric patients. The majority (60.9%) of responding hospitals had a minimum of four hematologists and/or oncologists. Eighty‐four percent of hospitals reported transfusing some apheresis platelets. The dose of platelet concentrates most frequently used for adults ranged from 6 to 10, with pools of 10 more commonly used in community hospitals. More than 70 percent of hospitals reported transfusing platelets primarily for prophylaxis: 60 percent of hospitals set the threshold platelet count for prophylactic platelet transfusion at 20,000 per microL, with approximately 20 percent each transfusing at higher and lower levels. A platelet count of 50,000 per microL was most frequently required for performance of a minor invasive procedure. CONCLUSION: The data from this study show that the majority of institutions use prophylactic platelet transfusion in both pediatric and adult hematology and/or oncology patients. However, there is considerable variation in platelet transfusion practice.

Reducing the Risk for Transfusion-transmitted Cytomegalovirus Infection

OBJECTIVE To define the groups of patients at risk for transfusion-transmitted cytomegalovirus infection and to define the methods to reduce this risk. DATA SOURCES English-language publications on transfusion medicine. STUDY SELECTION AND DATA EXTRACTION Studies were selected that described cytomegalovirus infection in transfusion-dependent patients. Special attention was paid to reports that included observations about the prevalence and clinical manifestations of cytomegalovirus infection and recommendations for the prevention of infection. DATA SYNTHESIS Some patients with impaired immune responses who have never been exposed to cytomegalovirus are at risk for transfusion-transmitted cytomegalovirus infection. This infection, which is associated with substantial morbidity and mortality, can be avoided by additional screening of blood donors or by special processing of components for transfusion. CONCLUSIONS Transfusion products that are unlikely to transmit cytomegalovirus infection can be prepared by filtration to remove leukocytes or can be obtained by selecting donors who are seronegative for antibodies to cytomegalovirus. These products are indicated for certain groups of immunosuppressed patients, including pregnant women who are cytomegalovirus seronegative, premature infants of low birth weight who are born to cytomegalovirus-seronegative mothers, cytomegalovirus-seronegative recipients of allogeneic bone marrow transplants from cytomegalovirus-seronegative donors, and cytomegalovirus-seronegative patients with the acquired immunodeficiency syndrome (AIDS).

Leukocyte Reduction in Blood Component Therapy

PURPOSE To review methods of preventing or minimizing the adverse effects associated with the transfusion of passenger leukocytes present in cellular blood components and to define groups of patients who are at risk for adverse effects. DATA SOURCES English-language articles on transfusion medicine. STUDY SELECTION Original reports describing the pathogenesis of leukocyte-induced adverse effects in transfusion recipients and the influence of leukocyte-reduced blood components on these effects. DATA EXTRACTION Evaluation of the diagnosis, transfusion history, and treatment of the study patients; the methods and results of leukocyte reduction; and specific outcomes, including development of alloimmunization to leukocytes, febrile reactions to transfusion, and platelet refractoriness. DATA SYNTHESIS Passenger leukocytes are the chief cause of alloimmunization to human leukocyte antigen (HLA) and leukocyte-specific antigens in transfusion recipients. Alloimmunization may result in febrile transfusion reactions, platelet refractoriness, and acute lung injury. Leukocytes are also the vector for transfusion-associated cytomegalovirus infection. Technologic advances in the leukocyte reduction of cellular blood components have made it possible to reduce the number of leukocytes to fewer than 10(7) per transfusion. Findings suggest that the use of leukocyte-reduced cellular blood components may minimize or prevent recurrent febrile reactions and alloimmunization to leukocyte antigens. Cytomegalovirus may not be transmitted by blood components containing fewer than 10(7) leukocytes. CONCLUSIONS Leukocyte reduction in red blood cell and platelet transfusions using third-generation filters is indicated for selected patients who are likely to receive long-term transfusion support, to prevent recurrent febrile reactions and to prevent or delay alloimmunization to leukocyte antigens. Leukocyte-depleted transfusions may also be indicated to delay or prevent refractoriness to platelet transfusion.

Current status of solvent/detergent-treated frozen plasma.

he Blood Products Advisory Committee of the Food and Drug Administration (FDA) recently recommended the approval of the use of solvent T and detergent treatment for fresh-frozen plasma (FFP). The FDA is expected to issue soon a license to VI. Technologies, Inc. (VITEX, New York, NY) to produce solventldetergent (SD)-treated plasma (SD plasma). Because an estimated 2 million units of plasma are transfused in the United States each year, the availability of an alternative blood component will likely have a significant impact on physician practices and on the supply of, and demand for, FFP This report reviews issues surrounding the development of SD technologies for use in virus inactivation, current clinical data relevant to the use of SD plasma, and answers to some commonly asked questions. The review is intended not to establish a standard or requirement for the use of FFP or SD plasma, but to provide background information for medical staffs as they consider transfusion alternatives. Development of guidelines or standards for voluntary compliance will require additional clinical data. Currently, most FFP is prepared in blood centers as a by-product of whole-blood processing, although FFP can also be prepared by plasmapheresis. FFP is a relatively safe biologic; its overall risk is estimated at 7.5 adverse events per 10,000 units transfused and 3.7 adverse events per 1,000

Hypotensive reactions : a previously uncharacterized complication of platelet transfusion ?

Background: In 1993, the American Association of Blood Banks (AABB) received reports of severe hypotensive reactions associated with platelet transfusions. The question arose as to whether these reports were indicative of a previously uncharacterized platelet transfusion reaction.

Transfusion-transmitted Babesia microti identified through hemovigilance.

BACKGROUND: Babesia microti, the primary cause of human babesiosis in the United States, is an intraerythrocytic parasite endemic to the Northeast and upper Midwest. Published studies indicate that B. microti increasingly poses a blood safety risk. The American Red Cross Hemovigilance Program herein describes the donor and recipient characteristics of suspected transfusion‐transmitted B. microti cases reported between 2005 and 2007.

Bacterial contamination of whole-blood-derived platelets: the introduction of sample diversion and prestorage pooling with culture testing in the American Red Cross.

BACKGROUND: Bacterial sepsis following whole blood–derived platelet (WBP) transfusion has remained a substantial patient risk, primarily due to a lack of practical and effective means to limit or detect bacterial contamination. We describe the risk of reported septic reactions to WBPs and the introduction of prestorage‐pooled whole blood–derived platelets (PSPs) collected using initial sample diversion and cultured for bacterial contamination.

TRANSFUSION COMPLICATIONS: Transfusion‐transmitted Babesia microti identified through hemovigilance

BACKGROUND: Babesia microti, the primary cause of human babesiosis in the United States, is an intraerythrocytic parasite endemic to the Northeast and upper Midwest. Published studies indicate that B. microti increasingly poses a blood safety risk. The American Red Cross Hemovigilance Program herein describes the donor and recipient characteristics of suspected transfusion‐transmitted B. microti cases reported between 2005 and 2007.

Transfusion practices in human immunodeficiency virus-infected patients

BACKGROUND: The reported immunomodulatory effects of transfusion raise concern about the potential for virus activation and tumor growth in human immunodeficiency virus (HIV)‐infected patients. In the absence of “standards” of transfusion practice for such patients, a survey of transfusion policies among institutions specializing in the care of HIV‐ infected patients was performed to delineate current practices.

The need for standardization of cryoprecipitate-derived fibrin adhesive

Fibrin glue is a biological tissue adhesive that has also been found to be an effective sealant and topical hemostatic agent. ‘J It is a two-component system in which a solution of concentrated fibrinogen and factor XIII are combined with a solution of thrombin and calcium to form a coagulum. The system essentially simulates the final stage of the clotting cascade, producing a fibrin clot within seconds after the administration of the thrombin-activating solution. In some clinical situations antifibrinolytic agents are also included to prevent lysis of the clot. Fibrin glue prepared commercially from pooled human plasma has been used extensively in Europe. Its use has been reported in a variety of procedures encompassing many surgical subspecialties including; microsurgery, neurosurgery, cardiothoracic surgery, plastic surgery, trauma surgery, oral surgery, orthopedic surgery, general surgery, urology and otolaryngology.1~2 More recently, it has been used in ophthalmology, as well as in obstetrics/gynecology, i.e. in vitro fertilization.3’4 The use of fibrin glue in the United States has developed more slowly than in the European countries, since the commercial kits for its preparation are not approved for use in humans, primarily due to the risk of transmitting viral diseases from a pooled source of fibrinogen. Over the past 10 years, there have been several alternative methods reported for obtaining fibrinogen from either autologous or single-donor homologous sources. These developments have sparked a resurgence of interest in the investigation and use of fibrin glue in the surgical community.’ As the potential applications for the use of fibrin glue expand (i.e. fibrin glue combined with antibiotics for antibacterial effect8) it is likely that the requests to blood banks and transfusion services to provide a consistent and highly concentrated source of fibrinogen and factor XIII will also increase.