Plasma and lipids from stored packed red blood cells cause acute lung injury in an animal model

Transfusion-related acute lung injury: an update

Transfusion-associated acute lung injury (TRALI) has emerged as a leading cause of transfusion-related morbidity and mortality. TRALI is characterized by acute non-cardiogenic pulmonary edema and respiratory compromise in the setting of transfusion. The study of TRALI has been hampered by inadequate case definitions and an incomplete understanding of the pathologic mechanisms. Recent consensus conferences took an important first step by providing a framework for case definition. Recent advances in the understanding of the pathogenesis of TRALI have also occurred. TRALI has been primarily attributed to donor leukocyte antibodies that are thought to interact with recipient neutrophils, resulting in activation and aggregation in pulmonary capillaries, release of local biologic response modifiers causing capillary leak, and lung injury. An alternate mechanism termed the "two hit" or "neutrophil priming" hypothesis postulates that a pathway to neutrophil activation and aggregation can occur without leukocyte antibodies. A first event such as sepsis or trauma can induce pulmonary endothelial activation, release of cytokines, and priming of neutrophils. A subsequent second event such as exposure to lipids, cytokines or antibodies in a blood component would then cause activation of adherent neutrophils and a release of bioreactive molecules leading to lung injury. There are limited clinical and animal studies to support the "two hit" model. These proposed mechanisms are not mutually exclusive in that donor leukocyte antibody can be pathogenic in both models and have implications for new strategies to prevent TRALI.

HLA class II antibodies in transfusion-related acute lung injury (TRALI). A case report

TRALI, a serious complication of blood transfusion, is underdiagnosed. Anti-granulocyte and anti-HLA class I molecules in donors or recipients and very recently, lipids in stored blood as well as anti-HLA class II have been associated with the syndrome. We present a TRALI case which occurred in a 56 year old woman after plasma transfusion. HLA class II antibodies were identified in the donor and were correlated with the recipients' HLA antigens. The presence of HLA class II antibodies without anti-HLA class I has been reported in very few cases and may facilitate the understanding of the pathogenesis of the syndrome.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a life-threatening adverse event of transfusion, which has an increasing incidence in the United States and is the leading cause of transfusion-related death. TRALI and acute lung injury (ALI) share a common clinical definition except that TRALI is temporally- and mechanistically-related to transfusion of blood or blood components. A number of different models have been proposed to explain the pathogenesis. The first is an antibody-mediated event whereby transfusion of anti-HLA, class I or class II, or anti-granulocyte antibodies into patients whose leukocytes express the cognate antigens. The antibody:antigen interaction causes complement-mediated pulmonary sequestration and activation of neutrophils (PMNs) resulting in TRALI. The second is a two-event model: the first event is the clinical condition of the patient resulting in pulmonary endothelial activation and PMN sequestration, and the second event is the transfusion of a biologic response modifier (including anti-granulocyte antibodies, lipids, and CD40 ligand) that activates these adherent PMNs resulting in endothelial damage, capillary leak, and TRALI. These hypotheses are discussed with respect to animal models and human studies that provide the experimental and clinical relevance. The definition of TRALI, patient predisposition, treatment, prevention and reporting guidelines are also examined.

Massive Blood Loss and Transfusion in Obstetrics and Gynecology

Massive perioperative or periparturitional bleeding occasionally occurs in obstetric and gynecologic patients. Placenta previa, uterine atony, and ectopic pregnancy are just a few examples of many conditions that could predispose patients to significant blood loss. Therefore, it is important for physicians specializing in obstetrics and gynecology to be proficient in managing episodes of massive hemorrhage and the practice of the most commonly used blood components. We review and update the management of massive hemorrhage for obstetrics and gynecologic patients. In addition, we explore blood component therapy, its risks and benefits.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning.

OBJECTIVES

After completion of this article, the reader should be able to explain the necessity of being proficient in managing episodes of massive hemorrhage, list the indications for use of various blood components, and summarize the risks and benefits of blood component therapy.

Insights from studies of blood substitutes in trauma

Most authorities believe that the greatest need for blood substitutes is in patients with unanticipated acute blood loss, and trauma is the most likely scenario. The blood substitutes reaching advanced clinical trials today are red blood cell (RBC) substitutes, derived from hemoglobin. The hemoglobin-based oxygen carriers (HBOCs) tested currently in FDA Phase III clinical trials are polymerized hemoglobin solutions. The standard approach to restoring oxygen delivery in hemorrhagic shock has been crystalloid administration to expand intravascular volume, followed by stored RBCs for critical anemia. However, allogenic RBCs may have adverse immunoinflammatory effects that increase the risk of postinjury multiple organ failure (MOF). Phase II clinical trials, as well as in vitro and in vivo work, suggest that resuscitation with a HBOC--in lieu of stored RBCs--attenuates the systemic inflammatory response invoked in the pathogenesis of MOF. Specifically, an HBOC has been shown to obviate stored RBC provoked neutrophil priming, endothelial activation, and systemic release of interleukins 6, 8, and 10. Based on this background and work by others, we have initiated a multicenter prehospital trial in which severely injured patients with major blood loss (systemic blood pressure <90 mmHg) are randomized to initial field resuscitation with crystalloid versus HBOC. During the hospital phase, the control group is further resuscitated with stored RBCs, whereas the study group receives HBOC (up to 6 units) in the first 12 h. The primary study endpoint is 30-day mortality, and secondary endpoints include reduction in allogenic RBCs, hemoglobin levels <5 g/dL, uncrossmatched RBCs, and MOF. The potential efficacy of HBOCs extends beyond the temporary replacement for stored RBCs. Hemoglobin solutions might ultimately prove superior in delivering oxygen to ischemic or injured tissue. The current generation of HBOCs can be lifesaving for acute blood loss today, but the next generation might be biochemically tailored for specific clinical indications.

Transfusion of the injured patient: proceed with caution

Transfusion of the injured patient with packed red blood cells (PRBCs) is a dynamic process requiring vigilance during the acute resuscitative and recovery phases postinjury. Although adverse events have been reported in 2% to 10% of injured patients, the advent of new detection techniques for viral pathogens has markedly decreased the risk of infectious transmission. However, transfusions are strongly associated with immunosuppression in the host, which may occur days after the initial injury and may lead to bacterial infections. Conversely, early transfusion of stored PRBCs, > 6 units in the first 12 h postinjury, contributes to an early state of hyperinflammation that is a strong, independent predictor of multiple organ failure (MOF) in those patients with intermediate injury severity scores. The roles of prestorage leukoreduction are also reviewed with respect to the promotion of both immunosuppression and hyperinflammation. We further summarize studies with hemoglobin substitutes, whose use may obviate many of the untoward events of transfusion and promise to lead to better outcomes for injured patients.

Transfusion-related acute lung injury

PURPOSE OF REVIEW

Transfusion-related acute lung injury is an uncommon complication of blood transfusion typically manifested by shortness of breath, fever, and hypotension. Transfusion-related acute lung injury is an important cause of transfusion-related morbidity and mortality.

RECENT FINDINGS

Much about the pathogenesis, treatment, and prevention of transfusion-related acute lung injury is poorly understood or is controversial. There is increasing recognition that transfusion-related acute lung injury is an important clinical syndrome, causing most transfusion-related deaths.

SUMMARY

In this report, what is known about transfusion-related acute lung injury is summarized with particular emphasis on recent studies. Some of the areas in which knowledge and/or consensus are currently lacking are identified.

Understanding the Consequences of Transfusion-Related Acute Lung Injury

Although the blood supply has become safer with regard to transmission of infectious agents, attention should continue to focus on understanding and eliminating the other serious risks associated with transfusion. Transfusion-related acute lung injury (TRALI) is one such risk, only recently becoming recognized as an important and potentially preventable clinical syndrome. Strategies for prevention of TRALI, however, must rely on knowledge regarding its etiology and diagnosis, and significant gaps in our understanding of the syndrome currently exist. This review summarizes what is known and unknown about the incidence, severity, etiology, diagnosis, and prevention of TRALI and the potential consequences of these knowledge gaps.

Transfusion-related acute lung injury (TRALI): a serious adverse event of blood transfusion

BACKGROUND AND OBJECTIVES

Analyses of fatal transfusion reactions in the UK and USA have shown that transfusion-related acute lung injury (TRALI) is among the most common causes of fatal transfusion reactions.

MATERIAL AND METHODS

Review of the literature was used to analyse TRALI.

RESULTS

TRALI is characterized by acute respiratory distress and non-cardiogenic lung oedema developing during, or within 6 h of, transfusion. In atypical cases, TRALI can become symptomatic much later. TRALI must be carefully differentiated from transfusion-associated circulatory overload. In its fulminant presentation, TRALI can be clinically indistinguishable from acute respiratory distress syndrome occurring as a result of other causes. The severity of TRALI depends upon the susceptibility of the patient to develop a more clinically significant reaction as a result of an underlying disease process, and upon the nature of triggers in the transfused blood components, including granulocyte-binding alloantibodies (immune TRALI) or neutrophil-priming substances such as biologically active lipids (non-immune TRALI). Immune TRALI, which occurs mainly after the transfusion of fresh-frozen plasma and platelet concentrates, is a rare event (about one incidence per 5000 transfusions) but frequently ( approximately 70%) requires mechanical ventilation (severe TRALI) and is not uncommonly fatal (6-9% of cases). Non-immune TRALI, which occurs mainly after the transfusion of stored platelet and erythrocyte concentrates, seems to be characterized by a more benign clinical course, with oxygen support sufficient as a form of therapy in most cases, and a lower mortality than immune TRALI.

CONCLUSIONS

By virtue of its morbidity and mortality, TRALI has become one of the most serious current complications of transfusion. To prevent further antibody-mediated cases, the evaluation of TRALI should include leucocyte antibody testing of implicated donors. However, further studies are necessary for the prevention of this serious transfusion complication.

Severe transfusion-related acute lung injury

A 46-yr-old man developed severe hypoxemia, pulmonary infiltrates, and an acute decrease in his leukocyte count shortly after transfusion of fresh-frozen plasma (FFP) during recovery from cardiac surgery. Cardiogenic pulmonary edema was excluded. Granulocyte-reactive and agglutinating alloantibodies were detected in the serum of the fresh-frozen plasma donor. The cross-match with the patient's granulocytes revealed antibodies specific for HLA class I. Transfusion-related acute lung injury (TRALI) is a potentially life-threatening, under-recognized and under-reported complication of transfusion. Conservative transfusion strategies and preclusion of the implicated blood donors with granulocyte-reactive antibodies from future blood donation may prevent TRALI and could save lives.

IMPLICATIONS

Transfusion-related acute lung injury (TRALI) is a potentially life-threatening, probably under-recognized and under-reported complication of transfusing blood products. Conservative transfusion strategies and preclusion of the implicated blood donors with granulocyte-reactive antibodies from future blood donation may prevent TRALI and potentially save lives.

Using a Miniaturized Circuit and an Asanguineous Prime to Reduce Neutrophil-Mediated Organ Dysfunction Following Infant Cardiopulmonary Bypass

BACKGROUND

Contemporary infant cardiopulmonary bypass circuits require a blood prime. Blood, especially when stored, generates an inflammatory response, and may contribute to organ dysfunction following cardiopulmonary bypass. We determined whether using a miniaturized circuit and an asanguineous prime attenuated the post-bypass inflammatory response, and improved right ventricular and pulmonary function.

METHODS

Sixteen infant piglets were placed into 3 groups based on prime components: group I (fresh blood), group II (stored blood), and group III (miniaturized circuit and asanguineous prime). Piglets were placed on cardiopulmonary bypass (100 mL.kg(-1).min(-1)), cooled to 18 degrees C, and underwent continuous perfusion (50 mL.kg(-1).min(-1)) for 30 minutes. They were rewarmed and separated from bypass. Serum tumor necrosis factor-alpha, right ventricular function, and pulmonary function were measured before and 30 minutes after bypass. Neutrophil priming activity in fresh and stored donor blood was also assessed.

RESULTS

Animals in group III had significantly improved cardiopulmonary function than the groups receiving blood (right ventricular cardiac index [mL.kg(-1).min(-1)]: group I [18.8 +/- 4.8], group II [21.5 +/- 6.2], and group III [81.2 +/- 11.4], p < 0.001; and pulmonary vascular resistance index [dynes.mL(-1).kg(-1)]: group I [1169 +/- 409], group II [1610 +/- 486], and group III [214 +/- 63], p = 0.03). Tumor necrosis factor-alpha (pg.mL(-1)) was lower in group III (1465 +/- 39) than in the groups receiving blood (3940 +/- 777), p = 0.002. Neutrophil priming activity (nmol.min(-1)) was also higher in stored blood (3.7 +/- 6) than in fresh blood (1.9 +/- 0.2), p = 0.02.

CONCLUSIONS

We have devised a unique miniaturized circuit that allows an asanguineous prime without hemodilution in an infant swine model. The employment of this circuit attenuates the post-bypass inflammatory response and has salutary effects on cardiopulmonary function.

Transfusion-Related Acute Lung Injury and the ICU

Transfusion-related acute lung injury (TRALI) has been the leading cause of transfusion-related deaths reported to the United States Food and Drug Administration for three consecutive years. Although traditionally TRALI has been viewed as having a one event pathogenesis (passive donor anti-leukocyte antibody interacting with a cognate antigen on the recipients leukocytes), emerging evidence suggests that TRALI is a multifactorial syndrome, and a true two-event subtype of ALI. Both recipient predisposition and biological response modifiers, generated during storage of cellular blood products, appear to play major pathogenetic roles. This review highlights recent advances in our knowledge of the pathophysiology of TRALI and recent progress towards a consensus definition of TRALI. It also guides the reader as to the recognition, investigation, and clinical management of TRALI.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is characterized by the sudden development of noncardlogenic pulmonary edema (acute lung Injury) after transfusion of blood products. Poor awareness of TRALI outside of the blood transfusion medicine community has led to a serious underestimation of this condition, currently the most Important severe complication of blood transfusion. Concern for the transfer of donor antileukocyte antibodies has prompted major changes in the management of the blood supply in some countries; however, recent studies have suggested alternative pathophyslological mechanisms for TRALI related to the shelf life of cellular blood products. Although all blood products have been implicated, most reported cases were associated with fresh frozen plasma, red blood cell, and platelet transfusions. Because many patients have additional predisposing factors for acute lung injury, carefully designed prospective studies are needed to fully assess attributable risk related to transfusion. The treatment of TRALI is supportive, and the prognosis is generally better than for other causes of acute lung Injury. As many as one third of all patients who develop acute lung injury have been exposed to blood products. TRALI may be an important and potentially preventable cause of acute lung injury.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is characterized by the sudden development of noncardlogenic pulmonary edema (acute lung Injury) after transfusion of blood products. Poor awareness of TRALI outside of the blood transfusion medicine community has led to a serious underestimation of this condition, currently the most Important severe complication of blood transfusion. Concern for the transfer of donor antileukocyte antibodies has prompted major changes in the management of the blood supply in some countries; however, recent studies have suggested alternative pathophyslological mechanisms for TRALI related to the shelf life of cellular blood products. Although all blood products have been implicated, most reported cases were associated with fresh frozen plasma, red blood cell, and platelet transfusions. Because many patients have additional predisposing factors for acute lung injury, carefully designed prospective studies are needed to fully assess attributable risk related to transfusion. The treatment of TRALI is supportive, and the prognosis is generally better than for other causes of acute lung Injury. As many as one third of all patients who develop acute lung injury have been exposed to blood products. TRALI may be an important and potentially preventable cause of acute lung injury.

Clinical predictors of and mortality in acute respiratory distress syndrome: Potential role of red cell transfusion*

OBJECTIVE

Clinical predictors for acute respiratory distress syndrome (ARDS) have been studied in few prospective studies. Although transfusions are common in the intensive care unit, the role of submassive transfusion in non-trauma-related ARDS has not been studied. We describe here the clinical predictors of ARDS risk and mortality including the role of red cell transfusion.

DESIGN

Observational prospective cohort.

SETTING

Intensive care unit of Massachusetts General Hospital.

PATIENTS

We studied 688 patients with sepsis, trauma, aspiration, and hypertransfusion.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred twenty-one (32%) subjects developed ARDS with a 60-day mortality rate of 46%. Significant predictors for ARDS on multivariate analyses included trauma (adjusted odds ratio [ORadj] 0.22, 95% confidence interval [CI] 0.09-0.53), diabetes (ORadj 0.58, 95% CI 0.36-0.92), direct pulmonary injury (ORadj 3.78, 95% CI 2.45-5.81), hematologic failure (ORadj 1.84, 95% CI 1.05-3.21), transfer from another hospital (ORadj 2.08, 95% CI 1.33-3.25), respiratory rate >33 breaths/min (ORadj 2.39, 95% CI 1.51-3.78), hematocrit >37.5% (ORadj 1.77, 95% CI 1.14-2.77), arterial pH <7.33 (ORadj 2.00, 95% CI 1.31-3.05), and albumin </=2.3 g/dL (ORadj 1.80, 95% CI 1.18-2.73). Packed red blood cell transfusion was associated with ARDS (ORadj 1.52, 95% CI 1.00-2.31, p = .05). Significant predictors for mortality in ARDS included age (ORadj 1.96, 95% CI 1.50-2.53), Acute Physiology and Chronic Health Evaluation III score (ORadj 1.78, 95% CI 1.16-2.73), trauma (ORadj 0.075, 95% CI 0.006-0.96), corticosteroids before ARDS (ORadj 4.65, 95% CI 1.47-14.7), and arterial pH <7.22 (ORadj 2.32, 95% CI 1.02-5.25). Packed red blood cell transfusions were associated with increased mortality in ARDS (ORadj 1.10 per unit transfused; 95% CI 1.04-1.17) with a significant dose-dependent response (p = .02).

CONCLUSIONS

Important predictors for the development of and mortality in ARDS were identified. Packed red blood cell transfusion was associated with an increased development of and increased mortality in ARDS.

Hypotension and acute pulmonary insufficiency following transfusion of autologous red blood cells during surgery: a case report and review of the literature

Transfusion of autologous blood is associated with fewer complications, although all untoward events of transfusion may not be negated with this strategy. We report a case of acute pulmonary insufficiency and hypotension following transfusion of autologous packed red blood cells (PRBCs) in a patient, who was undergoing major surgery. Anti-HLA class-I and class-II and anti-granulocyte antibodies were measured in the unit and in the recipient. Neutrophil (PMN)-priming activity was measured as the augmentation of the formyl-Met-Leu-Phe-activated respiratory burst. No immunoglobulins were identified; however, significant lipid-priming activity was present in the implicated, autologous PRBC unit that primed PMNs from both healthy people and the recipient. In addition, lipids, identical to those that accumulate during PRBC storage, caused significant hypotension when infused into rats at similar concentrations found in stored PRBCs. We conclude that the observed transfusion-related acute lung injury reaction with significant hypotension may be the result of two independent events: the first is related to inherent host factors, in this case major surgery, and the second is the infusion of lipids that accumulate during the routine storage of PRBCs.

Transfusion-related acute lung injury: Definition and review

BACKGROUND

Transfusion-related acute lung injury (TRALI) is now the leading cause of transfusion-associated mortality, even though it is probably still underdiagnosed and underreported.

NATIONAL HEART, LUNG, AND BLOOD INSTITUTE ACTION

The National Heart, Lung, and Blood Institute convened a working group to identify areas of research needed in TRALI. The working group identified the immediate need for a common definition and thus developed the clinical definition in this report.

MAJOR CONCEPTS IN THE DEFINITION

The major concept is that TRALI is defined as new acute lung injury occurring during or within 6 hrs after a transfusion, with a clear temporal relationship to the transfusion. Also, another important concept is that acute lung injury temporally associated with multiple transfusions can be TRALI, because each unit of blood or blood component can carry one or more of the possible causative agents: antileukocyte antibody, biologically active substances, and other yet unidentified agents.

RECOMMENDATION

Using the definition in this report, clinicians can diagnose and report TRALI cases to the blood bank; importantly, researchers can use this definition to determine incidence, pathophysiology, and strategies to prevent this leading cause of transfusion-associated mortality.

Syndrome de détresse respiratoire aiguë post-transfusionnel : une pathologie méconnue

Transfusion related acute lung injury (TRALI) is a rare but potentially severe complication of blood transfusion, manifested by pulmonary oedema, fever and hypotension. The signs and symptoms are often attributed to other clinical aspects of a patient's condition, and therefore, TRALI may go unrecognised. It has been estimated to be the third cause of transfusion related mortality, so it should be better diagnosed. Cases are related to multiple blood units, such as white blood cells, red blood cells, fresh frozen plasma, platelets or intravenous immunoglobulins. Physiopathology of TRALI is poorly understood, and still controversial. It is often due to an immunological conflict between transfused plasma antibodies and recipients' blood cells. These antibodies are either HLA (class I or II) or granulocyte-specific. They appear to act as mediators, which result in granulocytes aggregation, activation and micro vascular pulmonary injury. Lipids or cytokines in blood units are also involved as TRALI priming agents. Diagnosis is based on antibody screening in blood components and on specific-antigen detection in the recipient. The screening of anti-HLA or anti-granulocytes is recommended as part of prevention for female donors who had been pregnant. Preventative measures should also include leucoreduction and measures to decrease the amount of priming agents in blood components. In this article, we summarise what is known about TRALI, and we focus attention on unanswered questions and controversial issues related to TRALI.

Anemia, allogenic blood transfusion, and immunomodulation in the critically ill

Anemia and allogenic RBC transfusions are exceedingly common among critically ill patients. Multiple pathologic mechanisms contribute to the genesis of anemia in these patients. Emerging risks associated with allogenic RBC transfusions including the transmission of newer infectious agents and immune modulation predisposing the patient to infections requires reevaluation of current transfusion strategies. Recent data have suggested that a restrictive transfusion practice is associated with reduced morbidity and mortality during critical illness, with the possible exception of acute coronary syndromes. In this article, we review the immune-modulatory role of allogenic RBC transfusions in critically ill patients.

Reducing risk in infant cardiopulmonary bypass: the use of a miniaturized circuit and a crystalloid prime improves cardiopulmonary function and increases cerebral blood flow

Advances in perfusion strategies have played an important role in improving outcomes following repair of complex congenital heart defects. The influence of cooling strategy, temperature, duration of circulatory arrest, and specific method of cerebral perfusion on neurologic morbidity have been extensively characterized. Similarly, the ability of pharmacologic agents to modulate the post-cardiopulmonary bypass (CPB) inflammatory response has been previously elucidated in both the laboratory and clinical arena. However, modification of the circuit and priming components have received comparably less attention. We recently showed that employment of a miniaturized circuit and a bloodless prime reduce inflammation and have salutary effects on cardiopulmonary function following hypothermic low-flow perfusion (HLF), and that this circuit may also improve cerebral protection following both deep hypothermic circulatory arrest and HLF. The current report, therefore, reviews current strategies utilized to minimize post-CPB inflammation and highlights the empirical evidence from our laboratory demonstrating the beneficial role of a miniaturized extracorporeal circuit in this context.

Recipients of blood from a donor with multiple HLA antibodies: a lookback study of transfusion-related acute lung injury

BACKGROUND

The effects of transfusion of HLA antibodies to patients with corresponding antigens are not well known.

STUDY DESIGN AND METHODS

Records of patients who received blood from previous donations of a donor implicated in a case of transfusion-related acute lung injury (TRALI) were examined. The donor had multiple HLA antibodies reactive with 96 percent of HLA Class I antigens and 88 percent of HLA Class II antigens.

RESULTS

Among 103 patients (40 with a pretransfusion white blood cell [WBC] count of >/=3.5 x 10(9)/L), 1 patient met criteria for TRALI and had clinical evidence for diffuse alveolar hemorrhage. Among the subset of 55 patients (17 with a pretransfusion WBC count of 3.5 x 10(9)/L) with known HLA types, none developed TRALI even though 54 (98%) had one to five corresponding HLA antigens. In a subgroup of patients four of 62 patients with chest radiographs, developed new or worse bilateral infiltrates with implicated but not control units (p = 0.0625).

CONCLUSION

Transfusion of HLA antibodies from this donor to nonneutropenic patients did not cause TRALI, but there was a trend of an association with new or worse bilateral pulmonary infiltrates. Further research is needed to determine why transfusion of HLA antibodies to recipients with corresponding antigens causes TRALI in some cases and not in others.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a life-threatening adverse effect of transfusion that is occurring at increasing incidence in the United States and that, in the past 2 reporting years, has been the leading cause of transfusion-related death. TRALI and acute lung injury (ALI) share a common clinical definition except that TRALI is temporally and mechanistically related to the transfusion of blood/blood components. In prospective studies, 2 patient groups, 1 requiring cardiac surgery and 1 with hematologic malignancies and undergoing induction chemotherapy, were predisposed. Two different etiologies have been proposed. The first is a single antibody-mediated event involving the transfusion of anti-HLA class I and class II or antigranulocyte antibodies into patients whose leukocytes express the cognate antigens. The second is a 2-event model: the first event is the clinical condition of the patient resulting in pulmonary endothelial activation and neutrophil sequestration, and the second event is the transfusion of a biologic response modifier (including lipids or antibodies) that activates these adherent polymorphonuclear leukocytes (PMNs), resulting in endothelial damage, capillary leak, and TRALI. These hypotheses are discussed, as are the animal models and human studies that provide the experimental and clinical relevance. Prevention, treatment, and a proposed definition of TRALI, especially in the context of ALI, are also examined.

Acute lung injury after blood transfusion in mechanically ventilated patients

BACKGROUND

Liberal transfusion strategy increases the risk of acute lung injury (ALI), but specific transfusion-related factors have not been characterized. We tested the hypotheses that storage age and specific type of blood products are associated with increased risk of ALI in mechanically ventilated patients.

STUDY DESIGN AND METHODS

From a database of mechanically ventilated patients, we identified those who received blood products during the first 48 hours of intensive care. We extracted information about underlying ALI risk factors as well as the type, amount, and shelf age of administered blood products. Outcome was assessed by an independent, blind review of chest radiographs and clinical findings.

RESULTS

Of 181 patients transfused during the first 48 hours of mechanical ventilation, 60 (33%) developed ALI. There was no difference in average duration of red blood cells storage between patients who did and did not develop ALI (median, 18.5 vs. 17.5 days; p = 0.22). In a multivariable logistic regression analysis, important risk factors associated with the development of ALI were thrombocytopenia (odds ratio, 5.9; p = 0.004) and transfusion of fresh frozen plasma (odds ratio, 3.2; p = 0.023).

CONCLUSION

Thrombocytopenia and transfusion of fresh frozen plasma, but not storage age of red blood cells, were associated with the development of ALI in this cohort of mechanically ventilated patients.

Transfusion-Induced Leukocyte IL-8 Gene Expression is Avoided by the Use of Human Polymerized Hemoglobin

BACKGROUND

Red blood cell (pRBC) transfusion is an independent risk factor for multiple organ failure (MOF); a maladaptive immuno-inflammatory response is implicated. Interleukin-8 (IL-8) is one putative mediator of this response. We previously observed that injured patients resuscitated with pRBCs have increased plasma IL-8 compared with those given human polymerized hemoglobin (PolyHb). To further elucidate the mechanisms responsible for this difference in IL-8, we devised an ex-vivo transfusion model. We hypothesize that pRBC transfusion induces increased IL-8 gene expression that is avoided by the use of PolyHb.

METHODS

Human volunteer blood was incubated alone (RB) or with a major transfusion (50% exchange) of either post-storage leukoreduced O-pRBCs (RB + pRBC) or PolyHb (RB + PolyHb) for 30 minutes at 37 degrees C. Total leukocyte (TL) or polymorphonuclear leukocyte (PMN) total RNA was isolated and IL-8 mRNA quantified. Results are reported as amol IL-8 mRNA/microg total RNA +/- SEM. Stats: ANOVA with Bonferroni/Dunn post hoc analysis.

RESULTS

Simulated transfusion of pRBCs increased TL IL-8 mRNA (RB=0.28 +/- 0.10 amol/microg total RNA, RB + pRBC=2.24 +/- 0.25 amol/microg total RNA, p <0.01), whereas PolyHb did not (B + PolyHb=0.82 +/- 0.30 amol/microg total RNA). PolyHb IL-8 mRNA was less than pRBC transfused (p <0.01). In PMNs, simulated transfusion of pRBCs increase IL-8 mRNA (RB=3.17 +/- 1.05 amol/microg total RNA, RB + pRBC=7.60 +/- 1.79 amol/microg total RNA, p <0.01), whereas PolyHb did not (RB + PolyHb=4.53 +/- 1.64 amol/microg total RNA).

CONCLUSIONS

Stored pRBCs induces increased TL and PMN IL-8 gene expression, whereas human polymerized hemoglobin, in lieu or pRBCs, avoids this increase. These experimental results corroborate our previous clinical studies and further encourage the study of PolyHb as a resuscitation strategy to decrease postinjury MOF.

Prestorage leukocyte reduction prevents the formation of microaggregates that occlude artificial capillary vessels

PURPOSE

The passage behavior of stored blood through an artificial microchannel system, as a model of capillary vessels, was examined.

MATERIALS AND METHODS

Using blood obtained from a total of 17 healthy volunteers, untreated and prestorage leukocyte reduced blood, or untreated and prestorage microfiltered (35 microm-pore size) blood were stored, and then the passage behavior through the microchannels was evaluated. Also, using blood from 16 patients stored for about 2 weeks, the effect of a leukocyte reduction filter, microfilter or mesh filter (175-210 microm-pore size) on the passage through the microchannels was examined.

RESULTS

Untreated blood passed through the microchannels immediately after blood collection, but after 1 week occlusion of the microchannels occurred. Prestorage leukocyte reduced blood, however, passed through the microchannels for up to 6 weeks. Occlusion of the microchannels occurred with both the untreated and prestorage microfiltered blood. Although filtration through a leukocyte reduction filter provided blood that can pass through the microchannels, occlusion occurred with blood filtered in other way.

CONCLUSIONS

The present results show that stored blood produces abundant microaggregates, potentially occluding capillary vessels. These microaggregates are not formed after prestorage leukocyte reduction or can be removed by use of a leukocyte reduction filter.

Pulmonary injury from transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) can be a life-threatening complication of transfusion. In its severe form, it is clinically indistinguishable from acute respiratory distress syndrome. Symptoms typically begin within 4 hours of transfusion. TRALI has been reported after transfusion of all plasma-containing blood components. TRALI is associated with antibodies to white blood cells and biologically active lipids in trans-fused blood components.

Transfusion-related acute lung injury: a review

Transfusion-related acute lung injury (TRALI) is an underreported complication of transfusion therapy, and it is the third most common cause of transfusion-associated death. TRALI is defined as noncardiogenic pulmonary edema temporally related to transfusion therapy. The diagnosis of TRALI relies on excluding other diagnoses such as sepsis, volume overload, and cardiogenic pulmonary edema. Supportive diagnostic evidence includes identifying neutrophil or human leukocyte antigen (HLA) antibodies in the donor or recipient plasma. All plasma-containing blood products have been implicated in TRALI, with the majority of cases linked to whole blood, packed RBCs, platelets, and fresh-frozen plasma. The pathogenesis of TRALI may be explained by a "two-hit" hypothesis, with the first "hit" being a predisposing inflammatory condition commonly present in the operating room or ICU. The second hit may involve the passive transfer of neutrophil or HLA antibodies from the donor or the transfusion of biologically active lipids from older, cellular blood products. Treatment is supportive, with a prognosis substantially better than most causes of clinical acute lung injury.

Formyl-Met-Leu-Phe induces calcium-dependent tyrosine phosphorylation of Rel-1 in neutrophils

Chemoattractant priming and activation of PMNs results in changes in cytosolic Ca2+ concentration, tyrosine kinase activity, and gene expression. We hypothesize that the initial signaling for the activation of a 105kDa protein (Rel-1) requires Ca2+-dependent tyrosine phosphorylation. A rapid and time-dependent tyrosine phosphorylation of Rel-1 occurred following formyl-Met-Leu-Phe (fMLP) stimulation of human PMNs at concentrations that primed or activated the NADPH oxidase (10(-9) to 10(-6)M), becoming maximal after 30s. Pretreatment with pertussis toxin (Ptx) or tyrosine kinase inhibitors abrogated this phosphorylation and inhibited fMLP activation of the oxidase. The fMLP concentrations employed also caused a rapid increase in cytosolic Ca2+ but chelation negated the effects, including the cytosolic Ca2+ flux, oxidase activation, and the tyrosine phosphorylation of Rel-1. Conversely, chelation of extracellular Ca2+ decreased the fMLP-mediated Ca2+ flux, had no affect on the oxidase, and augmented tyrosine phosphorylation of Rel-1. Phosphorylation of Rel-1 was inhibited when PMNs were preincubated with a p38 MAP kinase (MAPK) inhibitor (SB203580). In addition, fMLP elicited rapid activation of p38 MAPK which was abrogated by chelation of cytosolic Ca2+. Thus, fMLP concentrations that prime or activate the oxidase cause a rapid Ca2+-dependent tyrosine phosphorylation of Rel-1 involving p38 MAPK activation.

Abdominal compartment syndrome: the cause or effect of postinjury multiple organ failure

Abdominal compartment syndrome (ACS) has emerged to be a significant problem in patients who develop postinjury multiple organ failure (MOF). Current laboratory research suggests that ACS could be a second hit for the development of MOF. Recent studies demonstrate that ACS is an independent predictor of MOF and that the prevention of ACS decreases the incidence of MOF. The Trauma Research Centers at the University of Colorado and the University of Texas-Houston Medical School are focused on defining the role of the gut in postinjury MOF. Because ACS is a plausible modifiable risk factor, our interest has been to 1) describe the epidemiology of ACS, 2) build prediction models, 3) provide strategies for prevention and treatment of ACS, and 4) develop relevant laboratory models. This review summarizes our findings.

Hypertonic saline prevents inflammation, injury, and impaired intestinal transit after gut ischemia/reperfusion by inducing heme oxygenase 1 enzyme

BACKGROUND

Hypertonic saline (HTS) has been shown to modulate the inflammatory response after shock. We have previously demonstrated that heme oygenase-1 (HO-1) induction is protective against gut dysfunction in models of shock-induced gut ischemia/reperfusion (I/R). We therefore hypothesized that HTS prevents gut inflammation, injury, and impaired transit by inducing HO-1 in a model of gut I/R.

METHODS

Rats underwent 60 minutes of superior mesenteric artery occlusion (SMAO) and then were resuscitated with 4 mL/kg of HTS, an equal volume of lactated Ringer's (LR) solution (4 mL/kg, low volume), or equal salt LR solution (32 mL/kg, high volume) and compared with SMAO alone or shams. A separate group was pretreated with the HO-1 blocker Sn protoporphyrin IX (SNP IX) before SMAO plus HTS. At 6 hours of reperfusion, transit was determined and ileum harvested for HO-1 (anti-inflammatory) and inducible nitric oxide synthase (proinflammatory) immunoreactivity, myeloperoxidase (MPO) activity, and histologic injury. Data are expressed as mean +/- SEM (analysis of variance).

RESULTS

Intestinal transit was severely impaired after SMAO (2.5 +/- 0.1), improved with low- and high-volume LR solution (3.2 +/- 0.2 and 3.1 +/- 0.1, not significant), but returned to sham (4.6 +/- 0.2) with HTS (4.8 +/- 0.2). Pretreatment with SNP abrogated this protective effect. Myeloperoxidase activity was significantly increased by SMAO (SMAO, 2.3 +/- 0.3; sham, 0.4 +/- 0.05), lessened by low- and high-volume LR solution (1.5 +/- 0.3 and 1.7 +/- 0.4), but returned to sham levels with HTS (1.0 +/- 0.01). Activity with SNP IX pretreatment was significantly increased (4.04 +/- 0.8). Mucosal injury followed a similar pattern. Inducible nitric oxide synthase was increased by SMAO and low- and high-volume LR solution (0.8 +/- 0.2, 0.8 +/- 0.03, and 0.8 +/- 0.02, respectively; sham, 0.5 +/- 0.02), but significantly reduced by HTS (0.7 +/- 0.02). HO-1 was induced by SMAO and low- and high-volume LR solution (0.33 +/- 0.02, 0.32 +/- 0.03, and 0.37 +/- 0.4, respectively; sham, 0.0 +/- 0.0), but was further increased with HTS (0.49 +/- 0.04).

CONCLUSION

HTS resuscitation protects against inflammation, injury, and impaired intestinal transit after gut I/R in part by inducing HO-1. This is a novel mechanism of HO-1 protection.

The next generation in shock resuscitation

Resuscitation of the severely injured patient who presents in shock has improved greatly, following focused wartime experience and insight from laboratory and clinical studies. Further benefit is probable from technologies that are being brought into clinical use, especially hypertonic saline dextran, haemoglobin-based oxygen carriers, less invasive early monitors, and medical informatics. These technologies could improve the potential of prehospital and early hospital care to pre-empt or more rapidly reverse hypoxaemia, hypovolaemia, and onset of shock. Damage control surgery and definitive interventional radiology will probably combine with more real-time detection and intervention for hypothermia, coagulopathy, and acidosis, to avoid extreme pathophysiology and the "bloody vicious cycle". Although now widely practised as standard of care in the USA and Europe, shock resuscitation strategies involving haemoglobin replacement and fluid volume loading to regain tissue perfusion and oxygenation vary between trauma centres. One of the difficulties is the scarcity of published evidence for or against seemingly basic intervention strategies, such as early or large-volume fluid loading. Standardised protocols for resuscitation, representing the best and most current knowledge of the clinical process, could be devised and widely implemented as interactive computerised applications among trauma centres in the USA and Europe. Prevention of injury is preferable and feasible, but early care of the severely injured patient and modulation of exaggerated systemic inflammatory response due to transfusion and other complications of traditional strategies will probably provide the next generation of improvements in shock resuscitation.

Supernatant from stored red blood cell primes inflammatory cells: influence of prestorage white cell reduction

BACKGROUND

The contribution of RBC transfusion to adverse patient outcomes is controversial. There is conflicting clinical data and limited biologic data that provide an underpinning biologic rationale for any adverse impacts from RBC transfusion. This study used in-vitro measures of PMN stimulation to determine the ability of supernatant from RBCs to stimulate allogeneic WBCs and to determine the influence of residual donor WBCs and storage time on the proinflammatory potential of RBCs.

STUDY DESIGN AND METHODS

Three types of RBCs were assessed: standard non-WBC-reduced RBCs (S-RBCs), buffy coat-poor RBCs (BCP-RBCs), and prestorage WBC-filtered RBC (LF-RBCs). Supernatant was collected weekly up to Day 42 of storage. PMN priming by supernatant from RBCs was determined by three methods: induction of CD11b expression on PMNs, induction of IL-8 release from PMNs, and the chemotactic effect of supernatant on PMNs.

RESULTS

Supernatant from S-RBCs induced the expression of CD11b on PMNs, primed PMNs to release IL-8, and was chemotactic for PMNs. The magnitude of this PMN-priming progressively amplified with storage time. In contrast, supernatant from BCP-RBCs or LF-RBCs did not significantly prime PMNs. The PMN-priming effect of supernatant from RBCs correlated more closely with the level of MNCs in the RBCs than PMN content.

CONCLUSION

Supernatant from stored S-RBCs prime unstimulated allogeneic PMNs in vitro. Prestorage buffy-coat WBC reduction was as effective as WBC depletion in abrogating this proinflammatory response elicited by supernatants from RBCs. The clinical consequences, if any, of these findings for transfusion recipients are unknown.

White blood cell-containing allogeneic blood transfusion, postoperative infection and mortality: a meta-analysis of observational 'before-and-after' studies

BACKGROUND AND OBJECTIVES

An association of white blood cell (WBC) reduction with decreased mortality was reported by one observational, before-and-after study. A meta-analysis was undertaken to examine whether this finding is supported by all the evidence currently available from before-and-after studies, and whether these studies support an association of WBC reduction with a decreased risk of postoperative infection.

MATERIALS AND METHODS

Observational, before-and-after studies were retrieved that reported on postoperative infection and/or mortality between January 1997 and June 2003. Six studies met the criteria for meta-analysis. Unadjusted summary odds ratios (ORs) of postoperative infection or mortality in patients transfused after (compared with before) WBC reduction were calculated across the studies if the hypothesis of homogeneity was not rejected. Adjusted summary ORs were calculated across three studies that had reported multivariate analyses.

RESULTS

There was an unadjusted association of WBC reduction with a decreased risk of postoperative infection [summary OR = 0.93; 95% confidence interval (95% CI), 0.88-0.99; P < 0.01] that did not persist following adjustment for confounding factors (summary OR = 0.94; 95% CI, 0.85-1.04; P > 0.05). There was neither an unadjusted nor an adjusted association of WBC reduction with decreased mortality (summary OR = 0.94; 95% CI, 0.71-1.23; P > 0.05; and OR = 0.92; 95% CI, 0.80-1.05; P > 0.05, respectively).

CONCLUSIONS

An association of WBC reduction with decreased mortality was not detected across the results available from all before-and-after studies. An unadjusted association of WBC reduction with a decreased risk of postoperative infection exists, but this was not detected across the three studies that reported multivariate analyses.

Transfusion Medicine

In the vein-to-vein flow of blood from donor to patient, the role of the transfusion medicine specialist has become increasingly centered at the bedside. Three clinically centered issues in blood safety and in blood conservation are presented in this chapter.

In Section I, Dr. Patricia Hewitt presents the epidemiologic and clinical evidence regarding new variant Creutzfeldt-Jakob disease (nvCJD) in the UK and its relevance to transfusion medicine. Lessons learned from the responses by the National Blood Service to this crisis are discussed, particularly in the context of recent evidence of a case of vCJD transmission by blood transfusion and a second case of apparent transmission of abnormal prion protein without development of clinical illness.

In Section II, Dr. Christopher Silliman and his colleagues summarize recent knowledge gained regarding transfusion-related acute lung injury (TRALI), which is now the leading cause of transfusion-related mortality. Two different etiologies have been proposed: a single antibody-medicated event, involving anti-HLA Class I and Class II, or anti-granulocyte antibodies; and a two-event model, which includes the clinical condition of the patient resulting in pulmonary endothelial activation and neutrophil sequestration. The second event is the transfusion of a biologic response modifier (lipids or antibodies) in the blood component that activates primed neutrophils. Prevention, clinical treatment, and proposed definition of TRALI are discussed.

In Section III, Dr. Lawrence Goodnough and colleagues present a transfusion medicine service approach to the utilization of recombinant factor VIIa (rFVIIa) in non-approved clinical settings. rFVIIa has a potential role as a hemostatic intervention in a variety of clinical settings, yet few clinical trials have been completed to date to guide indications for its use. The policies presented here are those in place at the authors’ medical center, and will undergo periodic review and revision as relevant new information and data are generated.

Vacuum-Assisted Wound Closure Achieves Early Fascial Closure of Open Abdomens after Severe Trauma

BACKGROUND

This study reviews the efficacy of vacuum-assisted wound closure (VAWC) to obtain primary fascial closure of open abdomens after severe trauma.

METHODS

The study population included shock resuscitation patients who had open abdomens treated with VAWC. The VAWC dressing was changed at 2- to 3-day intervals and downsized as fascial closure was completed with interrupted suture. The Trauma Research Database and the medical records were reviewed for pertinent data.

RESULTS

Over 26 months, 35 patients with open abdomens were managed by VAWC. Six died early, leaving 29 patients who were discharged. Of these, 25 (86%) were successfully closed using VAWC at a mean of 7 +/- 1 days (range, 3-18 days). Of the four patients that failed VAWC, two developed fistulas. No patients developed evisceration, intra-abdominal abscess, or wound infection.

CONCLUSION

VAWC achieved early fascial closure in a high percentage of open abdomens, with an acceptable rate of complications.

Effects of storage on efficacy of red cell transfusion: When is it not safe?

OBJECTIVE

To review the literature on red blood cell storage and its relationship to the efficacy of transfusion.

RESULTS

Well-documented changes occur to the red blood cell product during ex vivo storage. These changes include a reduction in red blood cell deformability, altered red blood cell adhesiveness and aggregability, and a reduction in 2,3-diphosphoglycerate and ATP. Bioactive compounds with proinflammatory effects also accumulate in the storage medium. These changes reduce posttransfusion viability of red blood cells. The clinical effects beyond posttransfusion viability are uncertain, but a growing body of evidence suggests that the storage lesion may reduce tissue oxygen availability, have proinflammatory and immunomodulatory effects, and influence morbidity and mortality. There are no published randomized, control trials examining the effect of storage duration on morbidity and mortality. Leukoreduction improves the quality of stored red blood cell products and in some studies has been shown to reduce morbidity and mortality.

CONCLUSION

Although storage duration influences the quality of red blood cell product, there is currently insufficient evidence to advocate shorter storage periods for red blood cell products.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is an uncommon complication of allogeneic blood transfusion manifested typically by shortness of breath, fever, and hypotension. It has been estimated to occur in 0.04% to 0.16% per patient transfused. TRALI has been identified as an important cause of transfusion-related morbidity and mortality. Despite the increasing recognition that TRALI represents an important clinical syndrome, much about the pathogenesis, treatment, and prevention of TRALI is poorly understood or is controversial. In this report, what is known about TRALI is summarized and some of the areas in which knowledge and/or consensus are currently lacking are identified.

Clinically relevant hypertonicity prevents stored blood- and lipid-mediated delayed neutrophil apoptosis independent of p38 MAPK or caspase-3 activation

BACKGROUND

Delayed apoptosis of primed neutrophils (PMNs) may facilitate PMN-mediated tissue injury leading to postinjury multiple organ failure. Aged (42-day-old) stored red blood cells (RBC42) delay PMN apoptosis through proinflammatory phospholipids such as platelet-activating factor (PAF) and lyso-phosphatidylcholine (LPC). Hypertonic saline (HTS) attenuates PMN cytotoxic functions. We hypothesized that clinically relevant HTS would provoke PMN apoptosis, as well as prevent stored blood- and lipid-mediated delayed PMN apoptosis through activation of p38 mitogen-activated protein kinase (MAPK) and caspase-3.

METHODS

PMNs harvested from healthy volunteers were incubated (5% CO(2), 37 degrees C, 24 hr) with RBC42 plasma, PAF (20 microM), or LPC (4.5 microM), with or without the p38 MAPK inhibitor SB 203580, the caspase-3 inhibitor zDEVD-fmk (10 micromol/L) or the pan-caspase inhibitor zVAD-fmk (20 micromol/L). Duplicate samples were preincubated in HTS (Na [180 mM]). Apoptotic index (% PMNs undergoing apoptosis) was assessed morphologically. p38 MAPK activation was assessed by Western blotting. Caspase-3 activity was measured colorimetrically.

RESULTS

PAF, LPC, and RBC42 plasma delayed apoptosis; HTS increased apoptosis compared with controls. HTS prevented PAF, LPC, and RBC42-delayed apoptosis. p38 MAPK was not activated by HTS; its inhibition had no effect on the actions of HTS. Caspase inhibition attenuated the ability of HTS to increase apoptosis, but it did not affect the ability of HTS to restore healthy PMN apoptosis in the presence of RBC42.

CONCLUSION

HTS increases PMN apoptosis and prevents stored blood- and lipid-mediated delayed PMN apoptosis. HTS may activate caspase-3, but alternative signaling pathways appear to be involved in modulating the effects of lipids on PMN apoptosis.

WBC-containing allogeneic blood transfusion and mortality: a meta-analysis of randomized controlled trials

BACKGROUND

An association between allogeneic blood transfusion (ABT) and mortality was reported by one team of investigators from randomized controlled trials (RCTs) comparing recipients of non-WBC-reduced versus WBC-reduced RBCs in open-heart surgery. A meta-analysis was undertaken to examine whether this finding can be generalized across clinical settings and/or transfused RBC components.

STUDY DESIGN AND METHODS

RCTs reporting on adverse immunomodulatory effects of ABT between January 1992 and August 2002 were retrieved. Fourteen studies had recorded mortality as a primary or secondary outcome and met all other criteria for meta-analysis. Summary ORs of mortality in a treatment arm receiving WBC-containing allogeneic RBCs versus a control arm receiving autologous or WBC-reduced allogeneic RBCs were calculated across studies, for groups of studies in which the hypothesis of homogeneity was not rejected.

RESULTS

There was no association between ABT and mortality across 14 RCTs reporting on short-term mortality (summary OR, 1.20; 95% CI, 0.87-1.65) or across 3 RCTs reporting on long-term mortality (summary OR, 0.87; 95% CI, 0.64-1.19). In subgroup analyses, RCTs using autologous blood or conducted in abdominal or vascular surgery showed no difference in mortality, but short-term mortality differed across 3 RCTs conducted in open-heart surgery (summary OR, 2.26; 95% CI, 1.31-3.90; p < 0.05) and 7 RCTs comparing recipients of non-WBC-reduced versus WBC-reduced allogeneic RBCs filtered before storage (summary OR, 1.45; 95% CI, 1.00-2.11; p >/= 0.05).

CONCLUSIONS

An association between ABT and either short-term or long-term mortality was not detected across clinical settings and transfused RBC components, but subgroup analyses suggest that an association between WBC-containing ABT and short-term mortality may exist in open-heart surgery and in settings where WBC-reduced allogeneic RBCs filtered before storage are administered.

Twelve-week RBC storage

BACKGROUND

Better storage can improve RBC availability and safety. Optimizing RBC ATP production and minimizing hemolysis has allowed progressively longer storage.

STUDY DESIGN AND METHODS

In the first study, 24 units of packed CPD RBCs were pooled in groups of four, realiquoted, and added to 300 mL of one of four variants of experimental additive solution 76 (EAS-76) containing 45, 40, 35, or 30 mEq per L NaCl. Units were sampled weekly for 12 weeks for morphologic and biochemical measures. In the second study, 10 volunteers donated 2 units of RBCs for a crossover comparison of Tc/Cr 24-hour in vivo recovery of 6-week storage in AS-1 versus 12-week storage in EAS-76 variant 6 (EAS-76v6) having 30 mEq per L NaCl.

RESULTS

RBCs stored in the lower salt variants of EAS-76 had higher concentrations of RBC ATP with less hemolysis and microvesiculation. RBC 2,3 DPG was preserved for two weeks. RBCs stored for 12 weeks in EAS-76v6 exhibited 78 +/- 4 percent 24-hour in vivo recovery.

CONCLUSIONS

It is possible to store RBCs for 12 weeks with acceptable recovery and 0.6 percent hemolysis and with normal 2,3 DPG concentrations for 2 weeks.

Possible mechanisms underlying development of transfusion-related acute lung injury: roles of anti-major histocompatibility complex class II DR antibody

Anti-major histocompatibility complex (anti-MHC) antibodies (Abs) and antipolymorphonuclear neutrophil (anti-PMN) Abs are generally considered as the main causes of the development of transfusion-related acute lung injury (TRALI), which is one of the most severe and sometimes lethal side effects of transfusion. These Abs are postulated to activate recipient's leucocytes, resulting in the release of soluble factors such as reactive oxygen species and detrimental cytokines and chemokines. The harmful effects on the lung tissues and resident leucocytes of these malignant factors are suspected to be profoundly involved in TRALI reactions. Several reports have indicated the principle effect of biologically active lipids on the pathogenesis of TRALI. However, the precise mechanisms of TRALI development remain unclear. To resolve this issue, we have been investigating cytokines that induce continuous inflammation of the lungs, specifically focusing on the cytokines derived from activated PMNs. We observed that the granulocyte-macrophage colony-stimulating factor (GM-CSF) markedly enhances the expression of MHC class II DR in PMNs. Moreover, MHC class II DR-expressing PMNs were also proved to express a high-affinity receptor for immunoglobulin E (IgE) (FcepsilonRI) and to produce tumour necrosis factor-alpha, interferon-gamma and interleukin-18 following a challenge with an anti-MHC class II DR monoclonal Ab (MoAb) or anti-DR antiserum. It is strongly suggested that amongst various inflammatory mediators, at least these three cytokines may contribute to the duration of inflammatory reactions in the lungs. Furthermore, FcepsilonRI expression, in GM-CSF-treated PMNs, suggests the involvement of PMNs in IgE-mediated immune reactions.

Plasma and lipids from stored platelets cause acute lung injury in an animal model

BACKGROUND

Transfusion of PLT concentrates may cause TRALI, a life-threatening reaction that has been linked to the infusion of anti-WBC immunoglobulins or older, stored PLTs that contain bioactive lipids. We hypothesize that lipids generated during storage of PLTs cause TRALI in a two-event animal model.

STUDY DESIGN AND METHODS

Plasma from both whole-blood PLTs (WB-PLTs) and apheresis PLTs (A-PLTs) was isolated on Day 0 (D.0) and Day 5 (D.5) of storage and heat-treated before use. Rats were pretreated with saline or 2 mg per kg endotoxin (LPS), anesthetized, and the lungs were ventilated, isolated, and perfused with saline or 5-percent PLT plasma. Pulmonary artery pressure, pulmonary edema, and leukotriene B4 levels (perfusate) were measured.

RESULTS

Plasma from D.5, but not D.0, of the identical WB-PLT and A-PLT units caused injury in lungs from LPS-pretreated rats (LPS/D.5) evidenced by increases in pulmonary edema and leukotriene B4 (p < 0.05). Lipid extracts and purified lipids from D.5 PLT plasma also elicited injury in lungs from LPS-pretreated rats (p < 0.05). Saline/D.5 plasma or lipids or LPS/D.0 did not cause pulmonary edema. Prestorage WBC reduction was ineffective in inhibiting TRALI.

CONCLUSION

PLT-induced TRALI may be the result of two events: 1) the clinical condition of the patient and 2) the infusion of lipids in stored PLTs.

Lysophosphatidylcholines prime the NADPH oxidase and stimulate multiple neutrophil functions through changes in cytosolic calcium

A mixture of lysophosphatidylcholines (lyso-PCs) are generated during blood storage and are etiologic in models of acute lung injury. We hypothesize that lyso-PCs stimulate polymorphonuclear neutrophils (PMNs) through Ca(2)(+)-dependent signaling. The lyso-PC mix (0.45-14.5 micro M) and the individual lyso-PCs primed formyl-Met-Leu-Phe (fMLP) activation of the oxidase (1.8- to 15.7-fold and 1.7- to 14.8-fold; P<0.05). Labeled lyso-PCs demonstrated a membrane association with PMNs and caused rapid increases in cytosolic Ca(2)(+). Receptor desensitization studies implicated a common receptor or a family of receptors for the observed lyso-PC-mediated changes in PMN priming, and cytosolic Ca(2)(+) functions were pertussis toxin-sensitive. Lyso-PCs caused rapid serine phosphorylation of a 68-kD protein but did not activate mitogen-activated protein kinases or cause changes in tyrosine phosphorylation. With respect to alterations in PMN function, lyso-PCs caused PMN adherence, increased expression of CD11b and the fMLP receptor, reduced chemotaxis, provoked changes in morphology, elicited degranulation, and augmented fMLP-induced azurophilic degranulation (P<0.05). Cytosolic Ca(2)(+) chelation inhibited lyso-PC-mediated priming of the oxidase, CD11b surface expression, changes in PMN morphology, and serine phosphorylation of the 68-kD protein. In conclusion, lyso-PCs affect multiple PMN functions in a Ca(2)(+)-dependent manner that involves the activation of a pertussis toxin-sensitive G-protein.