The effects of leukoreduced blood transfusion on infection risk following injury: a randomized controlled trial

Definitions of massive transfusion in adults with critical bleeding: a systematic review

BACKGROUND

Definitions for massive transfusion (MT) vary widely between studies, contributing to challenges in interpretation of research findings and practice evaluation. In this first systematic review, we aimed to identify all MT definitions used in randomised controlled trials (RCTs) to date to inform the development of consensus definitions for MT.

METHODS

We systematically searched the following databases for RCTs from inception until 11 August 2022: MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Cumulative Index to Nursing and Allied Health Literature, and Transfusion Evidence Library. Ongoing trials were sought from CENTRAL, ClinicalTrials.gov, and World Health Organisation International Clinical Trials Registry Platform. To be eligible for inclusion, studies had to fulfil all the following three criteria: (1) be an RCT; (2) include an adult patient population with major bleeding who had received, or were anticipated to receive, an MT in any clinical setting; and (3) specify a definition for MT as an inclusion criterion or outcome measure.

RESULTS

Of the 8,458 distinct references identified, 30 trials were included for analysis (19 published, 11 ongoing). Trauma was the most common clinical setting in published trials, while for ongoing trials, it was obstetrics. A total of 15 different definitions of MT were identified across published and ongoing trials, varying greatly in cut-offs for volume transfused and time period. Almost all definitions specified the number of red blood cells (RBCs) within a set time period, with none including plasma, platelets or other haemostatic agents that are part of contemporary transfusion resuscitation. For completed trials, the most commonly used definition was transfusion of ≥ 10 RBC units in 24 h (9/19, all in trauma), while for ongoing trials it was 3-5 RBC units (n = 7), with the timing for transfusion being poorly defined, or in some trials not provided at all (n = 5).

CONCLUSIONS

Transfusion of ≥ 10 RBC units within 24 h was the most commonly used definition in published RCTs, while lower RBC volumes are being used in ongoing RCTs. Any consensus definitions should reflect the need to incorporate different blood components/products for MT and agree on whether a 'one-size-fits-all' approach should be used across different clinical settings.

THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Association of Veterinary Hematology and Transfusion Medicine (AVHTM) Transfusion Reaction Small Animal Consensus Statement (TRACS) Part 2: Prevention and monitoring

OBJECTIVE

To systematically review available evidence to develop guidelines for the prevention of transfusion reactions and monitoring of transfusion administration in dogs and cats.

DESIGN

Evidence evaluation of the literature (identified through Medline searches through Pubmed and Google Scholar searches) was carried out for identified transfusion reaction types in dogs and cats. Evidence was evaluated using PICO (Population, Intervention, Comparison, Outcome) questions generated for each reaction type. Evidence was categorized by level of evidence (LOE) and quality (Good, Fair, or Poor). Guidelines for prevention and monitoring were generated based on the synthesis of the evidence. Consensus on the final recommendations and a proposed transfusion administration monitoring form was achieved through Delphi-style surveys. Draft recommendations and the monitoring form were made available through veterinary specialty listservs and comments were incorporated.

RESULTS

Twenty-nine guidelines and a transfusion administration monitoring form were formulated from the evidence review with a high degree of consensus CONCLUSIONS: This systematic evidence evaluation process yielded recommended prevention and monitoring guidelines and a proposed transfusion administration form. However, significant knowledge gaps were identified, demonstrating the need for additional research in veterinary transfusion medicine.

A comparison between leukocyte reduced low titer whole blood vs non-leukocyte reduced low titer whole blood for massive transfusion activation

BACKGROUND

Hemorrhagic shock is the leading cause of survivable death in trauma patients and recent literature has focused on resuscitation strategies including transfusing low-titer group O whole blood (LTOWB). Debate remains regarding whether leukocyte reduced (LR) whole blood is of clinical benefit or detriment to patients requiring massive transfusion. This study compares survival outcomes between LR-LTOWB and non-LR LTOWB.

STUDY DESIGN AND METHODS

The objective of this prospective, observational study was to detect any difference in 24-hour survival between patients receiving LR-LTOWB and non-LR LTOWB during their massive transfusion activation. Secondary objectives were to report any difference in ICU LOS, ventilation days, in-hospital survival, and hospital LOS. Data collected included patient sex, age, mechanism of injury, Injury Severity Score (ISS), Trauma Injury Severity Score (TRISS), cause of death, and number of LTOWB transfused.

RESULTS

A total of 167 patients received 271 LTOWB transfusions. There were 97 patients that received 168 units of LR-LTOWB while 70 patients received 103 units of non-LR LTOWB. The two study groups were comparable in terms of age, sex, ISS, TRISS, and the number of LTOWB transfused. The use of LR LTOWB during the initial massive transfusion activation in traumatically injured patients was not associated with increased 24-hour survival compared to when using non-LR LTOWB. No transfusion associated adverse events were reported.

CONCLUSIONS

The administration of either LR or non-LR LTOWB was not associated with >24 hours survival in patients presenting with massive hemorrhage. The high cost and the rapid decline in platelet count of LR whole blood may be a consideration.

Lack of persistent microchimerism in contemporary transfused trauma patients

BACKGROUND

Following transfusion, donor white blood cells (WBCs) can persist long-term in the recipient, a phenomenon termed transfusion-associated microchimerism (TA-MC). Prior studies suggest TA-MC is limited to transfusion following traumatic injury, and is not prevented by leukoreduction.

STUDY DESIGN AND METHODS

We conducted a prospective cohort study at a major trauma center to evaluate TA-MC following injury. Index samples were collected upon arrival, prior to transfusion. Follow-up samples were collected at intervals up to one year, and beyond for those testing positive for TA-MC. TA-MC was detected by real-time quantitative allele-specific polymerase chain reaction assays at the HLA-DR locus and several polymorphic insertion deletion sites screening for non-recipient alleles.

RESULTS

A total of 378 trauma patients were enrolled (324 transfused cases and 54 non-transfused controls). Mean age was 42 ± 18 years, 74% were male, and 80% were injured by blunt mechanism. Mean Injury Severity Score was 20 ± 12. Among transfused patients, the median (interquartile range) number of red cell units transfused was 6 (3,12), and median time to first transfusion was 9 (0.8,45) hours. Only one case of long-term TA-MC was confirmed in our cohort. We detected short-term TA-MC in 6.5% of transfused subjects and 5.6% on non-transfused controls.

CONCLUSIONS

In contrast to earlier studies, persistent TA-MC was not observed in our cohort of trauma subjects. Short-term TA-MC was detected, but at a lower frequency than previously observed, and rates were not significantly different than what was observed in non-transfused controls. The reduction in TA-MC occurrence may be attributable to changes in leukoreduction or other blood processing methods.

[Influence of massive blood transfusion and traumatic brain injury on TIMP‑1 and MMP‑9 serum levels in polytraumatized patients]

BACKGROUND

The morbidity and mortality of polytrauma patients are substantially influenced by the extent of the posttraumatic inflammatory reaction. Studies have shown that TIMP‑1 and MMP‑9 play a major role in posttraumatic immune disorder in genome-wide mRNA microarray analyses. Furthermore, both showed differential gene expression profiles depending on the clinical parameters massive blood transfusion and traumatic brain injury.

OBJECTIVE

The aim of this study was to evaluate TIMP‑1 and MMP‑9 serum concentrations in polytraumatized patients depending on the clinical parameters massive blood transfusion and traumatic brain injury in the early posttraumatic phase.

MATERIAL AND METHODS

Polytrauma patients (≥18 years) with an "Injury Severity Score" (ISS) ≥ 16 points were enrolled in this prospective study. Serum levels of TIMP‑1 and MMP‑9 were quantified (at 0 h, 6 h, 12 h, 24 h, 48 h and 72 h) using an enzyme-linked immunosorbent assay (ELISA). Groups were divided according to the clinical parameter massive blood transfusion (≥10 red blood cell units [RBC units] in the first 24-hour posttrauma) and traumatic brain injury (CCT postive [cranial computed tomography]).

RESULTS

Following massive blood transfusion (n = 21; 50 ± 15.7 years; ISS 39 ± 12.8 points) patients showed overall significantly increased TIMP‑1 levels (p = 0.003) and significantly higher TIMP‑1 values after 12-72 h. Traumatic brain injury patients (n = 28; 44 ± 19 years; ISS 42 ± 10 points) showed significantly higher MMP‑9 levels (p = 0.049) in the posttraumatic period.

CONCLUSION

Polytraumatized patients who received massive blood transfusions following major trauma showed significantly higher TIMP‑1 levels than patients who did not receive massive transfusions. This seems to be an expression of a massively excessive inflammatory reaction and therefore represents a substantial factor in the pathogenesis of severe posttraumatic immune dysfunction in this collective. Furthermore, the significant increase in MMP‑9 with accompanying traumatic brain injury reflects the pivotal role of matrix metalloproteinases in the pathophysiology of traumatic brain injury.

Therapeutics incorporating blood constituents

Blood deficiency and dysfunctionality can result in adverse events, which can primarily be treated by transfusion of blood or the re-introduction of properly functioning sub-components. Blood constituents can be engineered on the sub-cellular (i.e., DNA recombinant technology) and cellular level (i.e., cellular hitchhiking for drug delivery) for supplementing and enhancing therapeutic efficacy, in addition to rectifying dysfunctioning mechanisms (i.e., clotting). Herein, we report the progress of blood-based therapeutics, with an emphasis on recent applications of blood transfusion, blood cell-based therapies and biomimetic carriers. Clinically translated technologies and commercial products of blood-based therapeutics are subsequently highlighted and perspectives on challenges and future prospects are discussed.

STATEMENT OF SIGNIFICANCE

Blood-based therapeutics is a burgeoning field and has advanced considerably in recent years. Blood and its constituents, with and without modification (i.e., combinatorial), have been utilized in a broad spectrum of pre-clinical and clinically-translated treatments. This review article summarizes the most up-to-date progress of blood-based therapeutics in the following contexts: synthetic blood substitutes, acellular/non-recombinant therapies, cell-based therapies, and therapeutic sub-components. The article subsequently discusses clinically-translated technologies and future prospects thereof.

Effect of storage period of red blood cell suspensions on helper T-cell subpopulations

BACKGROUND

The aim of this study was to investigate the immunological alterations that occur during the storage of erythrocyte suspensions which may lead to transfusion-related immunomodulation following allogeneic blood transfusion.

MATERIALS AND METHODS

One part of the erythrocyte suspensions obtained from donors was leucoreduced while the other part was not. The leucoreduced (LR) and non-leucoreduced (NL) erythrocyte suspensions were then further divided into three equal amounts which were stored for 0, 21 or 42 days prior to measurements, by enzyme-linked immunosorbent assays, of cytokine levels in their supernatants. T-helper (Th) lymphocyte subgroups and gene expression were analysed in the NL erythrocyte suspensions by flow cytometry and real-time polymerase chain reaction, respectively. Results were compared to those of storage day 0.

RESULTS

By day 21, the number of Th2 cells had increased significantly and the numbers of Th1, Th22 and Treg cells had decreased significantly in the NL erythrocyte suspensions. On day 42 the numbers of Th2 and Treg cells in the NL suspensions were significantly increased while the number of Th1 cells was significantly decreased. The levels of transcription factors (TBX21, GATA3, and SPI.1) were significantly decreased on days 21 and 42, and AHR, FOXP3 and RORC2 levels were significantly increased on day 42 in NL erythrocyte suspensions. The decrease in interleukin-22 and increase in transforming growth factor-β levels found in NL erythrocyte suspensions on day 21 were statistically significant. Elevated levels of interleukin-17A were found in both LR and NL erythrocyte suspensions on day 42.

DISCUSSION

Our results suggest that allogeneic leucocytes and cytokines may play significant roles in the development of transfusion-related immunomodulation.

How do I implement a whole blood program for massively bleeding patients?

Building on the successful military experience, interest has been rekindled in transfusing whole blood (WB) early in the resuscitation of traumatically injured civilians, often before their ABO group is known. WB efficiently provides treatment for shock and coagulopathy, as well as platelet hemostatic function, to patients losing large volumes of blood. Unlike group O uncrossmatched red blood cells (RBCs), group O WB contains a substantial amount of plasma, which is incompatible with the RBCs of all non-group O recipients. Thus, when implementing a WB program, it is important to decide how to mitigate the risk of immune-mediated hemolysis. Other questions that a hospital needs to answer before implementing a WB program include determining which patients will be eligible for this product, how many units eligible patients can receive, for how long it should be stored and under what conditions, and how to monitor for adverse events. The donor center needs to consider if the WB should be leukoreduced, how to comply with the AABB's transfusion-related acute lung injury risk mitigation standard, and into which storage solution it should be collected. This report describes the multidisciplinary approach taken to implementing a civilian WB program at a multihospital health care system in the United States.

The effects of red cell transfusion donor age on nosocomial infection among trauma patients

BACKGROUND

We hypothesized that packed red blood cell (PRBC) transfusions from older donors would be associated with fewer nosocomial infections among trauma patients.

METHODS

We performed a four-year retrospective analysis of 264 consecutive adult trauma patients who received ≥1 PRBC transfusion during admission. The capacity of donor age to predict nosocomial infection was assessed by logistic regression.

RESULTS

Thirty-three percent of all patients developed a nosocomial infection. Donor age was significantly higher among patients with nosocomial infection (40.3 vs. 37.6 years, p = 0.035), and the incidence of infection was directly proportional to donor age. The association between donor age and infection was strongest among recipients age ≥60 years, and was significant on multivariate regression for this cohort (OR 1.07 (95% CI 1.01-1.13), p = 0.024).

CONCLUSIONS

Among trauma patients receiving PRBC transfusions, blood from older donors may be associated with increased risk for nosocomial infection.

Role of Leukoreduction of Packed Red Blood Cell Units in Trauma Patients: A Review

Hemorrhagic shock is a leading cause of mortality within the trauma population, and blood transfusion is the standard of care. Leukoreduction filters remove donor leukocytes prior to transfusion of blood products. While the benefits of leukocyte depletion are well documented in scientific literature, these benefits do not translate directly to the clinical setting. This review summarizes current research regarding leukoreduction in the clinical arena, as well as studies performed exclusively in the trauma population.

Molecular mechanisms of erythrocyte aging

Anemia and hemorrhagic shock are leading causes of morbidity and mortality worldwide, and transfusion of human blood products is the ideal treatment for these conditions. As human erythrocytes age during storage in blood banks they undergo many biochemical and structural changes, termed the red blood cell 'storage lesion'. Specifically, ATP and pH levels decrease as metabolic end products, oxidative stress, cytokines, and cell-free hemoglobin increase. Also, membrane proteins and lipids undergo conformational and organizational changes that result in membrane loss, viscoelastic changes and microparticle formation. As a result, transfusion of aged blood is associated with a host of adverse consequences such as decreased tissue perfusion, increased risk of infection, and increased mortality. This review summarizes current research detailing the known parts of the erythrocyte storage lesion and their physiologic consequences.

Leukoreduction for the prevention of adverse reactions from allogeneic blood transfusion

BACKGROUND

A blood transfusion is an acute intervention, implemented to solve life and health-threatening conditions on a short-term basis. However, blood transfusions have adverse events, some of them potentially related to immune modulation or to a direct transmission of infectious agents (e.g. cytomegalovirus). Leukoreduction is a process in which the white blood cells are intentionally reduced in packed red blood cells (PRBCs) in order to reduce the risk of adverse reactions. The potential benefits of leukoreduced PRBCs in all types of transfused patients for decreasing infectious and non-infectious complications remain unclear.

OBJECTIVES

To determine the clinical effectiveness of leukoreduction of packed red blood cells for preventing adverse reactions following allogeneic blood transfusion.

SEARCH METHODS

We ran the most recent search on 10th November 2015. We searched the Cochrane Injuries Group's Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), MEDLINE (OvidSP), Embase(OvidSP), CINAHL Plus (EBSCO), LILACS (BIREME), and clinical trials registers. In addition, we checked the reference lists of all relevant trials and reviews identified in the literature searches.

SELECTION CRITERIA

Randomised clinical trials including patients of all ages requiring PRBC allogeneic transfusion. Any study was eligible for inclusion, regardless of the length of participant follow-up or country where the study was performed. The primary outcome was transfusion-related acute lung injury (TRALI). Secondary outcomes were death from any cause, infection from any cause, non-infectious complications and any other adverse event.

DATA COLLECTION AND ANALYSIS

At least two review authors independently performed study selection, 'Risk of bias' assessments and data extraction. We estimated pooled relative risk for dichotomous outcomes, and we measured statistical heterogeneity using I² statistic. The random-effects model was used to synthesise results. We conducted a trial sequential analysis to assess the risk of random errors in cumulative meta-analyses.

MAIN RESULTS

Thirteen studies, most including adult patients, met the eligibility criteria. We found no clear evidence of an effect of leukoreduced PRBC versus non-leukoreduced PRBC in patients that were randomised to receive transfusion for the following outcomes: TRALI: RR 0.96, 95% CI 0.67 to 1.36, P = 0.80 from one trial reporting data on 1864 trauma patients. The accrued information of 1864 participants constituted only 28.5% of the diversity-adjusted required information size (DARIS) of 6548 participants. The quality of evidence was low. Death from any cause: RR 0.81, 95% CI 0.58 to 1.12, I² statistic = 63%, P = 0.20 from nine trials reporting data on 6485 cardiovascular surgical patients, gastro-oncology surgical patients, trauma patients and HIV infected patients. The accrued information of 6485 participants constituted only 55.3% of the DARIS of 11,735 participants. The quality of evidence was very low. Infection from any cause: RR 0.80, 95% CI 0.62 to 1.03, I² statistic = 84%, P = 0.08 from 10 trials reporting data on 6709 cardiovascular surgical patients, gastro-oncology surgical patients, trauma patients and HIV infected patients. The accrued information of 6709 participants constituted only 60.6% of the DARIS of 11,062 participants. The quality of evidence was very low. Adverse events: The only adverse event reported as an adverse event was fever (RR 0.81, 95% CI 0.64 to 1.02; I² statistic= 0%, P = 0.07). Fever was reported in two trials on 634 cardiovascular surgical and gastro-oncology surgical patients. The accrued information of 634 participants constituted only 84.4% of the DARIS of 751 participants. The quality of evidence was low. Incidence of other non-infectious complications: This outcome was not assessed in any included trial.

AUTHORS' CONCLUSIONS

There is no clear evidence for supporting or rejecting the routine use of leukoreduction in all patients requiring PRBC transfusion for preventing TRALI, death, infection, non-infectious complications and other adverse events. As the quality of evidence is very low to low, more evidence is needed before a definitive conclusion can be drawn.

The systemic immune response to trauma: an overview of pathophysiology and treatment

Improvements in the control of haemorrhage after trauma have resulted in the survival of many people who would otherwise have died from the initial loss of blood. However, the danger is not over once bleeding has been arrested and blood pressure restored. Two-thirds of patients who die following major trauma now do so as a result of causes other than exsanguination. Trauma evokes a systemic reaction that includes an acute, non-specific, immune response associated, paradoxically, with reduced resistance to infection. The result is damage to multiple organs caused by the initial cascade of inflammation aggravated by subsequent sepsis to which the body has become susceptible. This Series examines the biological mechanisms and clinical implications of the cascade of events caused by large-scale trauma that leads to multiorgan failure and death, despite the stemming of blood loss. Furthermore, the stark and robust epidemiological finding--namely, that age has a profound influence on the chances of surviving trauma irrespective of the nature and severity of the injury--will be explored. Advances in our understanding of the inflammatory response to trauma, the impact of ageing on this response, and how this information has led to new and emerging treatments aimed at combating immune dysregulation and reduced immunity after injury will also be discussed.

Factors Affecting Tissue Oxygenation in Erythrocyte Transfusions

Red blood cell transfusions are used to increase the oxygen-carrying capacity of blood in anemic states. But, because of the changes during storage of blood components and the specifics of preparation, erythrocytes may have controversial effects on tissue oxygenation and microcirculation. Also, the patient situation may play a role in the differing responses in oxygenation and microcirculation. In this review, the studies concerning the effects of banked blood and patient characteristics on microcirculation and tissue oxygenation are summarized.

Epidemiology of acute transfusions in major orthopaedic trauma

OBJECTIVES

The orthopaedic trauma-related blood product usage is largely unknown. Aim of this study was to describe the epidemiology of early (<24 hours of arrival) blood component use in major orthopaedic trauma.

DESIGN

12-month prospective observational study.

SETTING

John Hunter Hospital, Level 1 Trauma Center, New South Wales, Australia.

PATIENTS

64 consecutive trauma admissions identified, who had an orthopaedic injury and required at least 1 unit of packed red blood cells (PRBC) <24 hours of arrival.

INTERVENTION

Epidemiological study.

MAIN OUTCOME MEASURES

Demographics, orthopaedic injury type, procedure type, injury severity score, timing, place of first unit of transfusion, and blood component volumes were collected. Activation of the massive transfusion protocol was recorded. Primary outcome measures were intensive care unit admission and mortality.

RESULTS

From 965 major trauma admissions, 64 had one or more orthopaedic injuries and were transfused <24 hours. Forty-eight percent (31/64) required massive transfusion protocol activation. Average age was 41 ± 21 years, 73% (47/64) men. Eighty-four percent (54/64) required emergent orthopaedic intervention, 41% (22/54) having multiple procedures. Overall mortality was 13% (8/64). Twenty-five percent (16/64) required ≥10 units of PRBC. Average PRBC use was 7.2 ± 6.6 units and fresh frozen plasma use 4.3 ± 5.2 units. Thirty-nine percent (25/64) had a pelvic ring injury or acetabular fracture. Thirty-seven percent (24/64) had at least one femoral shaft fracture. Twenty patients had a total of 23 tibia fractures.

CONCLUSIONS

Orthopaedic trauma patients consume the majority of the blood products <24 hours among blunt trauma patients. This resource-intensive group requires frequent urgent surgical interventions and intensive care unit admission.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The acute immunological response to blood transfusion is influenced by polymicrobial sepsis

Blood transfusion is a well-established risk factor for adverse outcomes during sepsis. The specific mechanisms responsible for this effect remain elusive, and few studies have investigated this phenomenon in a model that reflects not only the clinical circumstances in which blood is transfused, but also how packed red blood cells (PRBCs) are created and stored. Using a cecal ligation and puncture model of polymicrobial sepsis as well as creating murine allogeneic and stored PRBCs in a manner that replicates the clinical process, we have demonstrated that transfusion of PRBCs induces numerous effects on leukocyte subpopulations. In polymicrobial sepsis, these responses are profoundly dissimilar to the proinflammatory effects of PRBC transfusion observed in the healthy mouse. Transfused septic mice, as opposed to mice receiving crystalloid resuscitation, had a significant loss of blood, spleen, and bone marrow lymphocytes, especially those with an activated phenotype. Myeloid cells behaved similarly, although they were able to produce more reactive oxygen species. Overall, transfusion in the septic mouse may contribute to the persistent immune dysfunction known to be associated with this process, rather than simply promote proinflammatory or anti-inflammatory effects on the host. Thus, it is possible that blood transfusion contributes to the multiple known effects of sepsis on leukocyte populations that have been shown to result in increased morbidity and mortality.

Acute transfusion practice during trauma resuscitation: who, when, where and why?

BACKGROUND

Early transfusion (ET=within 24h) has been shown to be required in approximately 5% of trauma patients. Critical care transfusion guidelines control transfusion triggers by evidence based cut-offs. Empirical guidelines influence decision making for ET in trauma.

AIM

to describe the patterns, indications and timing of ET at level 1 trauma centre.

METHODS

A 12-month prospective study was performed on all trauma admissions requiring ET. Demographics, mechanism, injury severity (ISS) were collected. Timing, location, volume, the clinician initiating first unit of transfusion, reason for transfusion was recorded, with corresponding blood gas results and physiological parameters. Mortality, ICU admission, length of stay, need for emergent surgery were outcomes.

RESULTS

From 965 trauma admissions 91 (9%) required ET (76% male, median age: 38 (10-88, IQR: 22-59), blunt mechanism: 87%, ISS: 25 (4-66, IQR: 16-34). 43% (39/91) had massive transfusion protocol (MTP) activation. ET was initiated in ED (52%), OR (38%) or ICU (10%). MTP transfusions were started at a median of 0.5h (0.5-4, IQR: 0.5-1.5), whilst non-MTP transfusions were initiated at a median 3h (0.5-23, IQR: 2-9). The first unit of ET was initiated by trauma surgeon (35%), anaesthetist (30%), ED (19%), ICU (13%) and general surgeon (3%). Transfusions triggers at the first unit of transfusion were 'expected or ongoing bleeding' 29%, dropping haemoglobin 26%, haemorrhagic shock 24%, hypotension 10%, tachycardia 8%. Median systolic blood pressure was 90 (45-125, IQR: 80-100), heart rate was 100 (53-163, IQR: 80-120), haemoglobin was 96 (50-166, IQR: 85-114)g/l and base excess was -4.2(-22.1 to 2.7, IQR: -7.2 to 2.4)mmol/l at the time of transfusion. Emergency surgery was required in 86% (78/91). ICU admission rate was 69% (63/91). Mortality was 14%. Low volume transfusion (1-2 units) was more likely to lead to overtransfusion (Hb>110 g/l).

CONCLUSION

The prospective evaluation of acutely transfused trauma patients showed a distinct pattern of transfusion triggers as the patient passes from ED to the OT and arrives to the ICU. The conventional transfusion trigger (haemoglobin level) is not appropriate in ET as early transfusion triggers are based on vital signs, blood gas results, injury patterns and anticipated major bleeding.

Neutrophils release extracellular DNA traps during storage of red blood cell units

BACKGROUND

Blood transfusion is associated with an increased risk of organ damage, infection, and alloimmunity. Neutrophil extracellular traps (NETs) are extracellular chromatin fibers decorated with neutrophil granular proteins that have been linked to cytotoxicity, thrombosis, and autoimmunity. We questioned whether neutrophils in blood products release NETs during storage and thus could contribute to adverse reactions from blood transfusions.

STUDY DESIGN AND METHODS

We analyzed supernatants and blood smears of human red blood cell (RBC) units that either were or were not leukoreduced before storage for markers of NETs.

RESULTS

We identified extracellular DNA, which was associated with histones and myeloperoxidase, a marker of neutrophil granules, in supernatants and blood smears of nonleukoreduced RBC units. These markers of NETs were absent in leukoreduced RBC units. Importantly, NETs passed through blood transfusion filters and could therefore potentially be infused into patients.

CONCLUSIONS

Our studies indicate that NETs are liberated during storage of nonleukoreduced RBC units. Future studies should address whether NETs in RBC units could potentially contribute to transfusion-associated complications.

The effects of non-leukoreduced red blood cell transfusions on microcirculation in mixed surgical patients

BACKGROUND

The impact of the storage process on oxygen-carrying properties of red blood cells and the efficacy of red blood cell (RBC) transfusions concerning tissue oxygenation remain an issue of debate in transfusion medicine. Storage time and leukocyte content probably interact since longer storage duration is thought to cause greater accumulation of leukocyte-derived cytokines and red blood cell injury.

OBJECTIVES

The aim of this study was to investigate the effects of storage and the efficacy of fresh (stored for less than 1 week) versus aged (stored for more than 3 weeks) non-leukoreduced RBC transfusions on sublingual microvascular density and flow in mixed surgical patients.

METHODS

Eighteen surgical patients were included in this study. Patients were randomly assigned into two groups receiving fresh (Group A) and aged (Group B) RBC transfusions. Sublingual microcirculatory functional capillary density (FCD) and microvascular flow index (MFI) were assessed using orthogonal polarization spectral (OPS) imaging. Measurements and collection of blood samples were performed after induction of general anesthesia, before RBC transfusion and 30 min after the RBC transfusion ended.

RESULTS

In both groups RBC transfusions caused an increase in hemoglobin concentration (p<0.001). RBC transfusions increased FCD in Group A (p<0.001), while FCD remained unaffected in Group B. Changes in MFI following RBC transfusion in both groups remained unaltered.

CONCLUSIONS

Fresh non-leukoreduced RBC transfusions but not RBCs stored for more than 3weeks, were effective in improving microciruculatory perfusion by elevating the number of perfused microvessels in mixed surgical patients.

Transfusion-associated microchimerism: the hybrid within

Microchimerism, the coexistence of genetically disparate populations of cells in a receptive host, is well described in both clinical and physiological settings, including transplantation and pregnancy. Microchimerism can also occur after allogeneic blood transfusion in traumatically injured patients, where donor cells have been observed decades after transfusion. To date, transfusion-associated microchimerism (TA-MC) appears confined to this clinical subset, most likely due to the immune perturbations that occur after severe trauma that allow foreign donor cells to survive. Transfusion-associated microchimerism appears to be unaffected by leukoreduction and has been documented after transfusion with an array of blood products. The only significant predictor of TA-MC to date is the age of red cells, with fresher units associated with higher risk. Thus far, no adverse clinical effect has been observed in limited studies of TA-MC. There are, however, hypothesized links to transfusion-associated graft vs host disease that may be unrecognized and consequently underreported. Microchimerism in other settings has gained increasing attention owing to a plausible link to autoimmune diseases, as well as its diagnostic and therapeutic potential vis-a-vis antenatal testing and adoptive immunotherapy, respectively. Furthermore, microchimerism provides a tool to further our understanding of immune tolerance and regulation.

The association of early transfusion with acute lung injury in patients with severe injury

BACKGROUND

Packed red blood cell (PRBC) transfusion is associated with acute lung injury (ALI) development after trauma, but this risk may not be constant through time after trauma. We hypothesized that the relationship between PRBC delivery and ALI risk varies through time after injury.

METHODS

Data were collected prospectively from 1999 to 2006. Inclusion criteria include the following: older than 13 years, surgical intensive care unit admission, and Injury Severity Score of 16 or greater. Exclusion criteria included discharge/death within 24 hours of admission. Patients were followed up prospectively for ALI development for 5 days after trauma. Discrete time models were fit to test the association of timing of PRBC delivery with the development of ALI while controlling for patient demographics, resuscitation variables, Injury Severity Score, and Acute Physiology and Chronic Health Evaluation III scores.

RESULTS

At total of 602 patients were included. Median age was 33 years, 77% were male, and 50% were African American. Using a discrete time-survival model, the relation between transfusion and ALI development was found to vary by transfusion time window (p < 0.0001). The major effect of PRBC delivery on ALI risk occurred in the first 24 hours after trauma; this finding persisted in multivariable modeling (adjusted odds ratio, 1.07 per unit; 95% confidence interval, 1.02-1.11, p < 0.001). Cumulative incidence of ALI approached 50% in patients receiving 6 U of PRBC or more in the first 24 hours.

CONCLUSION

The association between PRBC transfusion and ALI development in patients with trauma is time dependent, with PRBC delivery in the first 24 hours after injury driving the overall relation. Each PRBC unit during this period increases odds of subsequent ALI development by 7%.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level II.

Acute respiratory distress syndrome after trauma: development and validation of a predictive model

OBJECTIVE

To determine early clinical predictors of acute respiratory distress syndrome after major traumatic injury and characterize the performance of this acute respiratory distress syndrome prediction model, and two previously published acute respiratory distress syndrome prediction models, in an independent cohort of severely injured patients.

DESIGN

Prospective cohort study.

SETTING

University-affiliated level I trauma center in Seattle, WA, and nine hospitals participating in the Inflammation and Host Response to Injury Consortium.

PATIENTS

Model derivation utilized data from 224 patients participating in a randomized controlled trial. All models were validated in an independent cohort of 1,762 trauma patients.

MEASUREMENTS AND MAIN RESULTS

Variables strongly associated with acute respiratory distress syndrome in bivariate analysis (p<.01) were entered into a multiple logistic regression equation to generate an acute respiratory distress syndrome predictive model. We evaluated the performance of all models using the area under the receiver operator characteristic curve. Acute respiratory distress syndrome occurred in 79 subjects (35%) belonging to the development cohort and in 423 subjects (24%) from the validation cohort. Multivariable predictors of acute respiratory distress syndrome after trauma included subject age, Acute Physiology and Chronic Health Evaluation II Score, injury severity score, and the presence of blunt traumatic injury, pulmonary contusion, massive transfusion, and flail chest injury (area under the receiver operator characteristic curve 0.79 [95% confidence interval 0.73, 0.85]). Validation of the prediction model resulted in an area under the receiver operator characteristic curve of 0.71 (95% confidence interval 0.68, 0.74). Our model's performance in the validation cohort was superior to that of two other published acute respiratory distress syndrome prediction models (0.65 [95% confidence interval 0.63, 0.68] and 0.66 [95% confidence interval 0.64, 0.69], p<.01 for all comparisons).

CONCLUSIONS

Using routinely available clinical data, our prediction model identifies patients at high risk for acute respiratory distress syndrome early after severe traumatic injury. This predictive model could facilitate enrollment of subjects into future clinical trials designed to prevent this serious complication.

Transfusion immunomodulation--the case for leukoreduced and (perhaps) washed transfusions

During the last three decades, a growing body of clinical, basic science and animal model data has demonstrated that blood transfusions have important effects on the immune system. These effects include: dysregulation of inflammation and innate immunity leading to susceptibility to microbial infection, down-regulation of cellular (T and NK cell) host defenses against tumors, and enhanced B cell function that leads to alloimmunization to blood group, histocompatibility and other transfused antigens. Furthermore, transfusions alter the balance between hemostasis and thrombosis through inflammation, nitric oxide scavenging, altered rheologic properties of the blood, immune complex formation and, no doubt, several mechanisms not yet elucidated. The net effects are rarely beneficial to patients, unless they are in imminent danger of death due to exsanguination or life threatening anemia. These findings have led to appeals for more conservative transfusion practice, buttressed by randomized trials showing that patients do not benefit from aggressive transfusion practices. At the risk of hyperbole, one might suggest that if the 18th and 19th centuries were characterized by physicians unwittingly harming patients through venesection and bleeding, the 20th century was characterized by physicians unwittingly harming patients through current transfusion practices. In addition to the movement to more parsimonious use of blood transfusions, an effort has been made to reduce the toxic effects of blood transfusions through modifications such as leukoreduction and saline washing. More recently, there is early evidence that reducing the storage period of red cells transfused might be a strategy for minimizing adverse outcomes such as infection, thrombosis, organ failure and mortality in critically ill patients particularly at risk for these hypothesized effects. The present review will focus on two approaches, leukoreduction and saline washing, as means to reduce adverse transfusion outcomes.

Red Blood Cell Transfusion and Transfusion Alternatives in Traumatic Brain Injury

OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients through a literature search to identify original research on anemia and transfusion in TBI, the effects of transfusion on brain physiology, and the role of erythropoietin or hemoglobin-based blood substitutes (HBBSs). However, the amount of high-quality, prospective data available to help make decisions about when TBI patients should be transfused is very small. Randomized transfusion trials have involved far too few TBI patients to reach definitive conclusions. Thus, it is hardly surprising that there is widespread practice variation. In our opinion, a hemoglobin transfusion threshold of 7 g/dL cannot yet be considered safe for TBI patients admitted to hospital, and in particular to the ICU, as it is for other critically ill patients. Red blood cell transfusions often have immediate, seemingly beneficial effects on cerebral physiology, but the magnitude of this effect may depend in part upon how long the cells have been stored before administration. In light of existing physiological data, we generally aim to keep hemoglobin concentrations greater than 9 g/dL during the first several days after TBI. In part, the decision is based on the patient's risk of or development of secondary ischemia or brain injury. An increasing number of centers use multimodal neurologic monitoring, which may help to individualize transfusion goals based on the degree of cerebral hypoxia or metabolic distress. When available, brain tissue oxygen tension values less than 15-20 mm Hg or a lactate:pyruvate ratio greater than 30-40 would influence us to use more aggressive hemoglobin correction (e.g., a transfusion threshold of 10 g/dL). Clinicians can attempt to reduce transfusion requirements by limiting phlebotomy, minimizing hemodilution, and providing appropriate prophylaxis against gastrointestinal hemorrhage. Administration of exogenous erythropoietin may have a small impact in further reducing the need for transfusion, but it also may increase complications, most notably deep venous thrombosis. Erythropoietin is currently of great interest as a potential neuroprotective agent, but until it is adequately evaluated in randomized controlled trials, it should not be used routinely for this purpose. HBBSs are also of interest, but existing preparations have not been shown to be beneficial-or even safe-in the context of TBI.

Anemia in critical illness: insights into etiology, consequences, and management

Anemia is common in the intensive care unit, and may be associated with adverse consequences. However, current options for correcting anemia are not without problems and presently lack convincing efficacy for improving survival in critically ill patients. In this article we review normal red blood cell physiology; etiologies of anemia in the intensive care unit; its association with adverse outcomes; and the risks, benefits, and efficacy of various management strategies, including blood transfusion, erythropoietin, blood substitutes, iron therapy, and minimization of diagnostic phlebotomy.

Red blood cell transfusion in the neurological ICU

Red blood cell transfusion (RBCT) is a common therapy used in the intensive care unit to treat anemia. However, due to deleterious side effects and questionable efficacy, the clinical benefit of RBCT in patients who are not actively bleeding is unclear. The results of randomized controlled trials suggest there is no benefit to a liberal transfusion practice in general critical care populations. Whether the results of these trials are applicable to brain injured patients is unknown, as patients with primary neurological injury were excluded. This article reviews the efficacy and complications of RBCT, as well as the relationship between RBCT and its outcome in both the general intensive care unit and neurologically critically ill populations.

Prestorage leukoreduction abrogates the detrimental effect of aging on packed red cells transfused after trauma: a prospective cohort study. Am J Surg. 2012;203:198-204. [PMID: 21924400 DOI: 10.1016/j.amjsurg.2011.05.012]

BACKGROUND

The aim of this study was to prospectively duplicate previous retrospective findings showing that prestorage leukoreduction blunts the detrimental effect of aging on banked packed red blood cells transfused after injury.

METHODS

Over 19 months, trauma patients transfused with ≥4 U of packed red blood cells and surviving ≥24 hours were followed. The age of each unit was collected.

RESULTS

The cohort consisted of 153 patients. All models showed no association between advancing blood age and the likelihood of developing multiple-organ dysfunction syndrome or infections, regardless of whether the mean age of blood was analyzed as a continuous variable, as a percentage of blood received that was <14 days old, or as a dichotomized value >14 or <14 days old.

CONCLUSIONS

This prospective study duplicates previous retrospective findings of an abrogation of the detrimental effects of advancing mean packed red blood cell age on outcomes after trauma by performing prestorage leukoreduction.

The treatment of traumatic shock: recent advances and unresolved questions

Uncontrolled bleeding remains a leading cause of potentially preventable death after trauma. Timely, adequate resuscitation in traumatic shock is an essential, lifesaving aspect of polytrauma care. Whilst basic principles in the treatment of traumatic shock remain the same-achieving hemorrhage control and replacing lost volume, the way this is achieved has changed significantly in the last five years. The abandonment of blood pressure driven uncontrolled fluid resuscitation, the introduction of the concept of hemostatic resuscitation, and the increasing use of massive transfusion protocols have all contributed to an improvement in timely access to various blood products. The increase in knowledge regarding the pathophysiology of trauma, the availability of adjuncts, and the array of resuscitation monitoring options available have all contributed to a potentially improved approach to resuscitation. The purpose of this report is to review the most important advances in traumatic shock therapy in the last five years.

Rationale for randomized controlled trials and for intention-to-treat analysis in transfusion medicine: are they one and the same?

Articles on the appropriateness of intention-to-treat (ITT) vs. as-treated (AT) analyses of randomized controlled trials (RCTs) have highlighted issues relevant to drug trials, such as approaches suitable for 'explanatory' vs. 'pragmatic' RCTs. These considerations are less relevant to transfusion medicine RCTs, especially those of red blood cell transfusion therapies where the main issue is whether to include in the analysis randomized patients who did not receive transfusion. This article discusses issues pertinent specifically to transfusion medicine RCTs, and the thesis presented here is that the primary analysis of any transfusion medicine RCT must be based on the ITT principle. This is because the rationale for randomization is to avoid selection bias and to generate experimental arms that are comparable with respect to all, known and unknown, confounding factors. Only the entire arms produced by random allocation of subjects are so comparable, and only an ITT analysis of these entire arms fulfills the purpose of randomization. Withdrawals of randomized patients compromise the comparability of the groups and the rationale for randomization. Deviations from the ITT principle may be valid only when other conditions are met to ensure that non-adherence to ITT will not bias the results. For RCTs of red blood cell transfusion therapies, such conditions include that the RCTs be double-blind and that transfusion criteria should be applied consistently. Nonetheless, the rationale for ITT can be reversed in equivalence and non-inferiority trials where the finding of no difference is the objective of the research; thus, both ITT and AT analyses should be presented in these settings.

2011 update to the Society of Thoracic Surgeons and the Society of Cardiovascular Anesthesiologists blood conservation clinical practice guidelines

BACKGROUND

Practice guidelines reflect published literature. Because of the ever changing literature base, it is necessary to update and revise guideline recommendations from time to time. The Society of Thoracic Surgeons recommends review and possible update of previously published guidelines at least every three years. This summary is an update of the blood conservation guideline published in 2007.

METHODS

The search methods used in the current version differ compared to the previously published guideline. Literature searches were conducted using standardized MeSH terms from the National Library of Medicine PUBMED database list of search terms. The following terms comprised the standard baseline search terms for all topics and were connected with the logical 'OR' connector--Extracorporeal circulation (MeSH number E04.292), cardiovascular surgical procedures (MeSH number E04.100), and vascular diseases (MeSH number C14.907). Use of these broad search terms allowed specific topics to be added to the search with the logical 'AND' connector.

RESULTS

In this 2011 guideline update, areas of major revision include: 1) management of dual anti-platelet therapy before operation, 2) use of drugs that augment red blood cell volume or limit blood loss, 3) use of blood derivatives including fresh frozen plasma, Factor XIII, leukoreduced red blood cells, platelet plasmapheresis, recombinant Factor VII, antithrombin III, and Factor IX concentrates, 4) changes in management of blood salvage, 5) use of minimally invasive procedures to limit perioperative bleeding and blood transfusion, 6) recommendations for blood conservation related to extracorporeal membrane oxygenation and cardiopulmonary perfusion, 7) use of topical hemostatic agents, and 8) new insights into the value of team interventions in blood management.

CONCLUSIONS

Much has changed since the previously published 2007 STS blood management guidelines and this document contains new and revised recommendations.

The acute management of trauma hemorrhage: a systematic review of randomized controlled trials

Introduction

Worldwide, trauma is a leading cause of death and disability. Haemorrhage is responsible for up to 40% of trauma deaths. Recent strategies to improve mortality rates have focused on optimal methods of early hemorrhage control and correction of coagulopathy. We undertook a systematic review of randomized controlled trials (RCT) which evaluated trauma patients with hemorrhagic shock within the first 24 hours of injury and appraised how the interventions affected three outcomes: bleeding and/or transfusion requirements; correction of trauma induced coagulopathy and mortality.

Methods

Comprehensive searches were performed of MEDLINE, EMBASE, CENTRAL (The Cochrane Library Issue 7, 2010), Current Controlled Trials, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP) and the National Health Service Blood and Transplant Systematic Review Initiative (NHSBT SRI) RCT Handsearch Database.

Results

A total of 35 RCTs were identified which evaluated a wide range of clinical interventions in trauma hemorrhage. Many of the included studies were of low methodological quality and participant numbers were small. Bleeding outcomes were reported in 32 studies; 7 reported significantly reduced transfusion use following a variety of clinical interventions, but this was not accompanied by improved survival. Minimal information was found on traumatic coagulopathy across the identified RCTs. Overall survival was improved in only three RCTs: two small studies and a large study evaluating the use of tranexamic acid.

Conclusions

Despite 35 RCTs there has been little improvement in outcomes over the last few decades. No clear correlation has been demonstrated between transfusion requirements and mortality. The global trauma community should consider a coordinated and strategic approach to conduct well designed studies with pragmatic endpoints.

Duration of red cell storage influences mortality after trauma

BACKGROUND

Although previous studies have identified an association between the transfusion of relatively older red blood cells (RBCs) (storage ≥ 14 days) and adverse outcomes, they are difficult to interpret because the majority of patients received a combination of old and fresh RBC units. To overcome this limitation, we compared in-hospital mortality among patients who received exclusively old versus fresh RBC units during the first 24 hours of hospitalization.

METHODS

Patients admitted to a Level I trauma center between January 2000 and May 2009 who received ≥ 1 unit of exclusively old (≥ 14 days) vs. fresh (< 14 days) RBCs during the first 24 hours of hospitalization were identified. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated for the association between mortality and RBC age, adjusted for patient age, Injury Severity Score, gender, receipt of fresh frozen plasma or platelets, RBC volume, brain injury, and injury mechanism (blunt or penetrating).

RESULTS

One thousand six hundred forty-seven patients met the study inclusion criteria. Among patients who were transfused 1 or 2 RBC units, no difference in mortality with respect to RBC age was identified (adjusted RR, 0.97; 95% CI, 0.72-1.32). Among patients who were transfused 3 or more RBC units, receipt of old versus fresh RBCs was associated with a significantly increased risk of mortality, with an adjusted RR of 1.57 (95% CI, 1.14-2.15). No difference was observed concerning the mean number of old versus fresh units transfused to patients who received 3 or more units (6.05 vs. 5.47, respectively; p = 0.11).

CONCLUSION

In trauma patients undergoing transfusion of 3 or more RBC units within 24 hour of hospital arrival, receipt of relatively older blood was associated with a significantly increased mortality risk. Reservation of relatively fresh RBC units for the acutely injured may be advisable.

Informed consent in research to improve the number and quality of deceased donor organs

Improving the management of potential organ donors in the intensive care unit could meet an important public health goal by increasing the number and quality of transplantable organs. However, randomized clinical trials are needed to quantify the extent to which specific interventions might enhance organ recovery and outcomes among transplant recipients. Among several barriers to conducting such studies are the absence of guidelines for obtaining informed consent for such studies and the fact that deceased organ donors are not covered by extant federal regulations governing oversight of research with human subjects. This article explores the underexamined ethical issues that arise in the context of donor management studies and provides ethical guidelines and suggested regulatory oversight mechanisms to enable such studies to be conducted ethically. We conclude that both the respect that is traditionally accorded to the prior wishes of the dead and the possibility of postmortem harm support a role for surrogate consent of donors in such randomized controlled trials. Furthermore, although recipients will often be considered human subjects under federal regulations, several ethical arguments support waiving requirements for recipient consent in donor management randomized controlled trials. Finally, we suggest that new regulatory mechanisms, perhaps linked to existing regional and national organ donation and transplantation infrastructures, must be established to protect patients in donor management studies while limiting unnecessary barriers to the conduct of this important research.

Controversies related to red blood cell transfusion in critically ill patients

OBJECTIVE

To review the evolution of and controversies associated with allogenic blood transfusion in critically ill patients.

DATA SOURCES

Veterinary and human literature review.

HUMAN DATA SYNTHESIS

RBC transfusion practices for ICU patients have come under scrutiny in the last 2 decades. Human trials have demonstrated relative tolerance to severe, euvolemic anemia and a significant outcome advantage following implementation of more restricted transfusion therapy. Investigators question the ability of RBCs stored longer than 2 weeks to improve tissue oxygenation, and theorize that both age and proinflammatory or immunomodulating effects of transfused cells may limit efficacy and contribute to increased patient morbidity and mortality. Also controversial is the ability of pre- and post-storage leukoreduction of RBCs to mitigate adverse transfusion-related events.

VETERINARY DATA SYNTHESIS

While there are several studies evaluating the transfusion trigger, the RBC storage lesion and transfusion-related immunomodulation in experimental animal models, there is little research pertaining to clinical veterinary patients.

CONCLUSIONS

RBC transfusion is unequivocally indicated for treatment of anemic hypoxia. However, critical hemoglobin or Hct below which all critically ill patients require transfusion has not been established and there are inherent risks associated with allogenic blood transfusion. Clinical trials designed to evaluate the effects of RBC age and leukoreduction on veterinary patient outcome are warranted. Implementation of evidence-based transfusion guidelines and consideration of alternatives to allogenic blood transfusion are advisable.

Post injury multiple organ failure

The understanding of post injury multiple organ failure (MOF) has evolved considerably since it was first described more than 30 years ago. Improved trauma care has decreased the mortality of single organ injury, although these patients may go on to MOF. There has been significant investigation in both the basic science and clinical understanding of MOF. This research has altered management strategies thereby decreasing the incidence and mortality related to MOF. Despite this MOF remains the greatest contributor to late trauma death and morbidity. This review defines essential terminology, examines the historical perspective of MOF, describes common scoring systems, describes the changes in epidemiology, discusses the aetiology and pathophysiology, reviews current prevention, resuscitation and treatment strategies and provides future direction for research.

Risk of cardiac arrhythmias and conduction abnormalities in patients with acute myocardial infarction receiving packed red blood cell transfusions

PURPOSE

Although transfusion has been linked to the development of atrial fibrillation (AF) in cardiac surgical patients, this association has not been investigated in patients with acute myocardial infarction (AMI). Evidence supports an inflammatory mechanism in the development of AF, and red cell transfusions also elicit an inflammatory response. We therefore sought to evaluate whether packed red blood cell transfusion increases the risk of AF, ventricular tachycardia (VT), and other arrhythmias and conduction abnormalities in patients with AMI.

MATERIALS AND METHODS

This is a retrospective study on patients with AMI and no prior history of AF, admitted to a critical care area and entered in Project Impact database from 08/2003-12/2007. Primary outcome measures were new-onset cardiac arrhythmias or conduction disturbances.

RESULTS

Transfused patients had significantly higher incidences of AF (4.7% vs 1.3%, P = .008), cardiac arrest (9.5% vs 1.7%, P < .001) and heart block (3.4% vs 0.1%, P < .001), and a trend toward a higher incidence of VT (3.4% vs 1.3%, P = .058). Multivariate regression analysis confirmed transfusion as an independent risk factor for "non-lethal" cardiac events (AF/heart block; odds ratio [OR], 4.7 [1.9-11.9]; P = .001), "lethal" events (VT/cardiac arrest; OR, 2.4 [1.1-5]; P = .016), and all cardiac events (OR, 2.8 [1.5-65.1]; P = .001). Transfused patients had significantly longer length of stay (P < .0001) and significantly higher mortality rates than nontransfused patients (OR, 3 [1.7-5.5]; P < .001).

CONCLUSIONS

Packed red blood cell transfusion is independently associated with an increased risk of new-onset cardiac arrhythmias and conduction abnormalities in the setting of AMI, even after controlling for traditional risk factors.

Prestorage leukoreduction ameliorates the effects of aging on banked blood. ACTA ACUST UNITED AC. 2010;69:330-337. [PMID: 20699741 DOI: 10.1097/ta.0b013e3181e0b253]

BACKGROUND

Previous studies have demonstrated that the transfusion of older blood is independently associated with higher rates of infectious complications, multiple organ failure, and mortality. Putative mechanisms implicate leukocytes in stored blood that generate immunomodulatory mediators as the stored blood ages. The purpose of this retrospective cohort study was to describe the effect of prestorage leukoreduction (PS-LR) on the detrimental clinical effects of increasing age on blood products used in trauma patients.

METHODS

All patients receiving >or=6 units of packed red cells and surviving >or=48 hours since May 1999 when institutional universal PS-LR was begun were identified. Transfusion requirements, demographic data, and causes of death were collected. Blood bank records were reviewed to determine the age of each unit of blood transfused. Multivariate logistic regression was used to determine the relationship between the age of PS-LR transfused blood and mortality after adjusting for total transfusion requirement, patient age, Injury Severity Score, head Abbreviated Injury Score, mechanism of injury, and gender. A subgroup analysis was performed excluding those patients in whom care was withdrawn at 48 hours to 72 hours postinjury for brain death or neurologic devastation.

RESULTS

A total of 399 patients, receiving 6,603 units of blood, met inclusion criteria. Mortality analysis showed that increasing Injury Severity Score, patient age, head Abbreviated Injury Score, and number of units of packed red cells transfused were all independently associated with an increased risk of death. When mean age of blood was analyzed as a continuous variable, a significant reduction in the risk of death with increasing mean age of transfused PS-LR blood was noted (odds ratio [OR], 0.959; 95% confidence interval [CI], 0.924-0.996). Both of these findings persisted when the mean age of blood was dichotomized at 14 days (OR, 0.426; 95% CI, 0.182-0.998) and 21 days (OR, 0.439; 95% CI, 0.225-0.857). The area under the curve for the receiver operating characteristics of our mortality model was 0.90. After excluding 13 patients in whom care was withdrawn 48 hours to 72 hours postinjury for brain death or neurologic devastation, the mortality analysis still showed that increasing injury severity, number of units of packed red cells transfused, and age were all independently associated with an increased risk of death. The protective effect of receiving older blood seen in the all-cause mortality analysis disappeared because no association was found between odds of dying and increasing age of packed red blood cells units transfused. This was true whether the mean age of transfused blood was dichotomized at 14 days (OR, 0.93; CI, 0.30-2.83) or at 21 days (OR, 0.54; CI, 0.25-1.16).

CONCLUSION

Our data suggest that the deleterious effects of aging on banked blood are ameliorated by PS-LR. We are currently conducting a prospective observational study in an effort to duplicate the findings of this retrospective investigation.

A systematic review of randomized controlled trials exploring the effect of immunomodulative interventions on infection, organ failure, and mortality in trauma patients

Introduction

Following trauma, patients may suffer an overwhelming pro-inflammatory response and immune paralysis resulting in infection and multiple organ failure (MOF). Various potentially immunomodulative interventions have been tested. The objective of this study is to systematically review the randomized controlled trials (RCTs) that investigate the effect of potentially immunomodulative interventions in comparison to a placebo or standard therapy on infection, MOF, and mortality in trauma patients.

Methods

A computerized search of MEDLINE, the Cochrane CENTRAL Register of Controlled Trials, and EMBASE yielded 502 studies, of which 18 unique RCTs were deemed relevant for this study. The methodological quality of these RCTs was assessed using a critical appraisal checklist for therapy articles from the Centre for Evidence Based Medicine. The effects of the test interventions on infection, MOF, and mortality rates and inflammatory parameters relative to the controls were recorded.

Results

In most studies, the inflammatory parameters differed significantly between the test and control groups. However, significant changes in infection, MOF, and mortality rates were only measured in studies testing immunoglobulin, IFN-γ, and glucan.

Conclusions

Based on level 1b and 2b studies, administration of immunoglobulin, IFN-γ, or glucan have shown the most promising results to improve the outcome of trauma patients.

Blood still kills: six strategies to further reduce allogeneic blood transfusion-related mortality

After reviewing the relative frequency of the causes of allogeneic blood transfusion-related mortality in the United States today, we present 6 possible strategies for further reducing such transfusion-related mortality. These are (1) avoidance of unnecessary transfusions through the use of evidence-based transfusion guidelines, to reduce potentially fatal (infectious as well as noninfectious) transfusion complications; (2) reduction in the risk of transfusion-related acute lung injury in recipients of platelet transfusions through the use of single-donor platelets collected from male donors, or female donors without a history of pregnancy or who have been shown not to have white blood cell (WBC) antibodies; (3) prevention of hemolytic transfusion reactions through the augmentation of patient identification procedures by the addition of information technologies, as well as through the prevention of additional red blood cell alloantibody formation in patients who are likely to need multiple transfusions in the future; (4) avoidance of pooled blood products (such as pooled whole blood-derived platelets) to reduce the risk of transmission of emerging transfusion-transmitted infections (TTIs) and the residual risk from known TTIs (especially transfusion-associated sepsis [TAS]); (5) WBC reduction of cellular blood components administered in cardiac surgery to prevent the poorly understood increased mortality seen in cardiac surgery patients in association with the receipt of non-WBC-reduced (compared with WBC-reduced) transfusion; and (6) pathogen reduction of platelet and plasma components to prevent the transfusion transmission of most emerging, potentially fatal TTIs and the residual risk of known TTIs (especially TAS).

Why implement universal leukoreduction?

The improvement of transfusion medicine technology is an ongoing process primarily directed at increasing the safety of allogeneic blood component transfusions for recipients. Over the years, relatively little attention had been paid to the leukocytes present in the various blood components. The availability of leukocyte removal (leukoreduction) techniques for blood components is associated with a considerable improvement in various clinical outcomes. These include a reduction in the frequency and severity of febrile transfusion reactions, reduced cytomegalovirus transfusion-transmission risk, the reduced incidence of alloimmune platelet refractoriness, a possible reduction in the risk of transfusion-associated variant Creutzfeldt-Jakob disease transmission, as well as reducing the overall risk of both recipient mortality and organ dysfunction, particularly in cardiac surgery patients and possibly in other categories of patients. Internationally, 19 countries have implemented universal leukocyte reduction (ULR) as part of their blood safety policy. The main reason for not implementing ULR in those countries that have not appears to be primarily concerns over costs. Nonetheless, the available international experience supports the concept that ULR is a process that results in improved safety of allogeneic blood components.

Use of leukoreduced blood does not reduce infection, organ failure, or mortality following trauma

Background

Leukoreduced (LR) blood has been demonstrated to reduce morbidity and mortality in high-risk surgical patients, but not in trauma patients. The objective of the present study was to determine the effect of LR blood on morbidity and mortality. We hypothesized that the use of LR blood does not improve outcome in trauma patients.

Methods

This study was a retrospective cohort analysis of trauma patients transfused at a level 1 Trauma Center from 2001 to 2004. Between 2002 and 2003, LR blood was transfused. Prior to that time and subsequent to it, non-leukoreduced (NLR) blood was transfused. This created two historical comparison groups. Data collected included patient demographics, units of blood transfused, intensive care unit (ICU) and hospital days, ventilator days, injury severity score (ISS), mortality, presence of acute respiratory distress syndrome (ARDS), and infectious complications. A multiple organ dysfunction syndrome (MODS) score was calculated.

Results

The distribution of patients was as follows: 284 patients received only NLR blood, 153 received only LR blood, and 58 received at least one unit of each. The mean ISS was similar (NLR: 26, LR: 24; P > 0.1). No differences were seen between groups in units transfused (6.2 vs. 5.5), number of ICU days (8.2 vs. 9.0), number of hospital days (16.9 vs. 18.6), number of ventilator days (6.1 vs. 5.7), incidence of ARDS (8.3% vs. 8.5%), MODS score (5.5 vs. 5.9), mortality rate (15.1% vs. 15.7%), or infection rate (36% vs. 30%) (P > 0.1).

Conclusions

This study represents the largest series comparing trauma patients who received either LR or standard blood transfusions. The use of LR blood does not improve outcome in trauma patients.