Effect of a liberal versus restrictive transfusion strategy on mortality in patients with moderate to severe head injury.
Objective: To compare a restrictive versus a liberal transfusion strategy in patients with moderate to severe closed head injury following multiple trauma in 13 Canadian intensive care units (ICUs). Methods: This is a subgroup analysis of a multicenter randomized controlled clinical trial involving sixty-seven critically ill patients from the Transfusion Requirements in the Critical Care trial who sustained a closed head injury. Patients had a hemoglobin concentration less than 9.0 g/dL within 72 hours of admission to the ICU. Patients were randomized to a restrictive allogeneic red blood cell transfusion strategy (hemoglobin 7.0 g/dL and maintained between 7.0 and 9.0 g/dL) or a liberal strategy (hemoglobin 10.0 g/dL and maintained between 10.0 and 12.0 g/dL). Results: Baseline characteristics in the restrictive ( n = 29) and the liberal ( n = 38) transfusion groups were comparable. Average hemoglobin concentrations and red blood cell units transfused per patient were significantly lower in the restrictive compared to the liberal group. The 30-day all-cause mortality rates in the restrictive group were 17% as compared to 13% in the liberal group (risk difference 4.1 with 95% confidence interval [CI], 13.4 to 21.5, p = 0.64). Presence of multiple organ dysfunction (12.1 +/- 6.4 versus 10.6 +/- 6.3, p = 0.35) and changes in multiple organ dysfunction from baseline scores adjusted for death (4.5 +/- 6.2 versus 3.4 +/- 6.2, p = 0.49) were similar between the restrictive and liberal transfusion groups, respectively. Median length of stay in ICU (10 days, interquartile range 5 to 21 days versus 8 days, interquartile range 5 to 11 days, p = 0.26) and hospital (27 days, interquartile range 14 to 39 days versus 30.5 days, interquartile range 17 to 47 days, p = 0.72) were similar between the restrictive and liberal transfusion groups. Conclusions: We were unable to detect significant improvements in mortality with a liberal as compared to restrictive transfusion strategy in critically ill trauma victims with moderate to severe head injury.
Neurocrit Care. 2006;5(1):4-9
Giving blood: an individual right or the expression of a social responsability? The donnors' position in the debates on blood transfusion.
This debate questions the donor's position within the transfusional framework. How are blood donation regulations initiated and implemented? Experts called upon this question insist on the necessity to better inform about such regulations so that they can be rapidly approved and in order to keep donors from adverse reactions linked to blood donations. How to make donors' rejections more tolerable? Contra-indications are a source of anxiety for the person whose blood sample is not accepted. While blood transfusion has never been safer in the past than it is today in wealthy countries, one should ask the question whether the donor is or not the victim of doubts still weighing down on this activity. Implementing the precautionary principle may indeed lead transfusion supervisors to take brutal decisions detrimental to the donor, seeming rather inspired by political or media pressures than calling on scientific or economic rigorous principles. What does the donor selection aim at in terms of prevention and public health? What about the renewal of donor associations' directors? Where are we at with the homosexual rejection trends? Such are the issues as those induced by the current debate.
Transfus Clin Biol. 2006 Sep 5; [Epub ahead of print]
An Overview of Prion Biology and the Role of Blood Filtration in Reducing the Risk of Transfusion-Transmitted Variant Creutzfeldt-Jakob Disease.
Prions are infectious proteins believed to be responsible for a variety of progressive and fatal neurodegenerative diseases, collectively referred to as transmissible spongiform encephalopathies (TSE). By 1996, it was recognized that ingestion of beef from cattle afflicted with a TSE known as bovine spongiform encephalopathy, could result in a devastating human TSE known as variant Creutzfeldt- Jakob disease (vCJD). Two recent reports of probable transfusion-transmitted vCJD have raised concerns about the safety of the blood supply. The relatively long asymptomatic latency of vCJD, as well as the lack of sensitive and specific antemortem tests, increase the risk that asymptomatic, infected individuals may become blood donors. To this point, donor deferral has been a strategy used to reduce this risk. Nevertheless, this strategy may be unreliable and, furthermore, may threaten blood availability. Leukoreduction has also been helpful in reducing cell-associated infectious prion, which has been reported to reduce up to 42% of the infectivity in blood. Proprietary prion affinity surface modifications have been developed and applied to filters, which exploit an understanding of the unique chemical characteristics of prion surfaces. These have been successfully adapted to existing high-efficiency blood filter matrices for the reduction of prions present in blood components for transfusion.
Transfus Med Rev. 2006; 20: 190-206
Transfusion-associated Chagas disease (American trypanosomiasis) in Mexico: implications for transfusion medicine in the United States.
Background: Trypanosoma cruzi, the protozoan cause of Chagas disease, causes life-long infection and is easily transmitted by blood transfusion. Our goals were to determine the prevalence of Chagas disease among donors in five Mexican blood banks, to look for evidence of transmission of T. cruzi by transfusion, and to evaluate two serologic assays for Chagas disease. Study design and methods: Blood samples from donors were tested initially with the Abbott Chagas EIA or the Meridian Chagas’ IgG ELISA. Samples giving readings that were at least 50% of the cutoffs were run in a confirmatory radioimmune precipitation assay (RIPA), as were samples from recipients of blood products from RIPA-positive donors. Results: The overall prevalence of Chagas disease was 1/133 (55/7,296; 0.75%). In addition, 4 of 9 surviving recipients of blood products from T. cruzi-infected donors were in turn infected. Using the manufacturers’ recommended cutoffs, the sensitivity and specificity of the Abbott test were 92.0% (23/25) and 99.8% (2,865/2,872) respectively, and the corresponding values for the Meridian assay were 70.0% (21/30) and 100.0% (4,369/ 4,369). Conclusions: These findings indicate clearly that transfusion-associated transmission of T. cruzi is occurring in the study areas. Serologic testing of blood donors for Chagas disease should be performed there and in the rest of Mexico. The two screening assays evaluated may lack the accuracy necessary for blood donor testing when used as suggested by the manufacturers.
Transfusion 2006; 46: 298-304
Detection of West Nile virus in the Mexican blood supply.
Background: West Nile virus (WNV) is the etiologic agent of an emerging disease in the Western Hemisphere that can be transmitted to humans by blood transfusion. WNV first appeared in the United States in 1999, in Canada in 2001, and in Mexico in 2002. The aim of this nationwide study was to determine the prevalence of WNV in blood donors in Mexico as a first step in preventing its transfusion-associated transmission.
Study design and methods: In July and August 2004, a total of 3856 fresh plasma specimens collected from each state’s center for blood transfusion in 29 of 31 Mexican states were screened with an investigational WNV assay (Procleix,® Gen-Probe Inc. and Chiron Corp.), a nucleic acid test based on transcription mediated amplification (TMA). Reactive specimens were confirmed with a second TMA-based test, the alternative WNV assay (Gen-Probe), and with WNV capture enzyme linked immunosorbent assays (ELISAs) for detection of immunoglobulin M (IgM) and IgG antibodies. In addition, 3714 frozen plasma samples collected in 2002 and 2003 were similarly tested.
Results: One of 3856 fresh samples from an asymptomatic donor from Chihuahua was reactive by both TMA-based tests and IgM ELISA, suggesting a recently acquired infection. The observed percentage of viremic donors blood donors was 0.03 percent. Results from frozen samples were not included in the prevalence calculation and none were TMA-reactive for WNV.
Conclusions: WNV is present in the Mexican blood supply and measures should be taken to reduce the risk of transfusion transmission.
Transfusion 2006; 46: 111-17
Anti-HBc screening of blood donors: a comparison of nine anti-HBc tests
Schmidt M, Nubling CM, Scheiblauer H, Chudy M, Walch LA, Seifried E, Roth WK, Hourfar MK.
Institute of Transfusion Medicine and Immunohematology, German Red Cross, Johann Wolfgang Goethe University, Frankfurt, Germany.
Background and Objectives Since voluntary introduction of hepatitis B virus (HBV) minipool nucleic acid amplification technology (NAT) at the German Red Cross, the expected residual risk of a transfusion-associated HBV infection has been estimated to be 1 : 500 000 - about 10 times higher than for human immunodeficiency virus (HIV) or hepatitis C virus (HCV) infection. Donors demonstrating chronic positivity for antibody to hepatitis B core antigen (anti-HBc), negativity for hepatitis B surface antigen (HBsAg) and polymerase chain reaction (PCR)-negative with a low virus load are a major cause of this increased risk. Materials and Methods Ten-thousand blood donors from our blood-donation centre were screened for anti-HBc using the current PRISM(R) HBc and the new PRISM(R) HBcore assay to evaluate the diagnostic sensitivity and specificity of these tests. PRISM(R) HBc- or PRISM(R) HBcore-reactive samples were further analysed using seven additional tests for anti-HBc, two tests for antibody to hepatitis B surface antigen (anti-HBs), one test for antibody to hepatitis B envelope antigen (anti-HBe) and three HBV NAT assays. Results From a total of 10 000 donors, nine and 14 samples were reactive only in the PRISM(R) HBc and the PRISM(R) HBcore, respectively, whereas 165 samples were reactive in both anti-HBc assays. Further analysis of these 188 anti-HBc-reactive specimens in a total of nine different anti-HBc assays revealed concordant results for 162 (86.2%) specimens. Sample cut-off values for anti-HBc were significantly (P < 0.01) lower for anti-HBc-only reactive samples compared with specimens that were also reactive for anti-HBs or anti-HBe. Conclusions Both PRISM anti-HBc assays revealed that approximately 1.8% of non-prescreened blood donors from Germany were reactive for anti-HBc. Although sensitivity was comparable between both assays, specificity was increased significantly with the PRISM(R) HBcore. High anti-HBc sample cut-off values were indicative for reactivity in other HBV parameters and for concordant results in the nine different anti-HBc assays. Look-back investigations are necessary to estimate the infection risk both of anti-HBc-only positive and of anti-HBc/anti-HBs-positive blood transfusions.
Vox Sang. 2006 Oct;91(3):237-43
Hepatitis B virus DNA in blood donors with anti-HBc as a possible indicator of active hepatitis B virus infection in Yucatan, Mexico.
Summary. Hepatitis B virus (HBV) may be present in serum even when negative for HBV surface antigen (HBsAg). If routine screening of sera for anti-HBV core antigen (anti-HBc) is not done, low-level HBV viraemia may not be identified. A study was done on the presence of HBV DNA in serum samples from Mexican blood donors negative for HBsAg. Sera from 158 volunteer blood donors, negative for HBsAg and anti-HBs, but positive for anti-HBc, were analysed using nested polymerase chain reaction (PCR). HBV DNA was detected in sera from 13 (8_23%) of the 158. Specificity of the PCR-amplified products was corroborated using Southern blot. Single strand conformation polymorphism (SSCP) analysis showed identical SSCP-banding patterns for all 13 PCR products, suggesting similar cDNA sequences. Occult HBV infection was observed in approximately 8% of anti-HBc only donors. The absence of HBsAg in the blood of apparently healthy individuals may not be sufficient to ensure lack of circulating HBV, and blood containing anti-HBc only may be infectious until proven otherwise.
Transfusion Medicine, 2005; 15: 371–78
Transfusion audit of fresh-frozen plasma in southern Taiwan.
Yeh CJ, Wu CF, Hsu WT, Hsieh LL, Lin SF, Liu TC. Blood Bank, Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
Background and Objectives The demand for transfusions has increased rapidly in southern Taiwan. Between 1993 and 2003, requests for fresh-frozen plasma (FFP) in particular rose dramatically at Kaohsiung Medical University Hospital (KMUH). Transfusion orders were not tightly regulated, and inappropriate use of blood products was common. Materials and Methods We carried out a prospective analysis of transfusion requests from October 2003 to January 2004 at KMUH, and then repeated the audit for another 3-month period after the clinical faculty had undergone five sessions of education on transfusion guidelines. Later, our consultant haematologist applied computerized guidelines to periodic audits. Results A 5.2% decrease in inappropriate FFP usage followed the educational programme and a further 30% reduction took place after the application of computerized transfusion guidelines. With the guidelines and periodic audits, FFP transfusions decreased by 74.6% and inappropriate requests from 65.2% to 30%. Conclusions Hospital policy, computerized transfusion guidelines and periodic audits greatly reduced inappropriate FFP transfusions. An educational campaign had a more limited effect
Vox Sang. 2006 Oct;91(3):270-4