Transfusion-related acute lung injury

RBC Transfusions Are Associated With Prolonged Mechanical Ventilation in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Blood products are often transfused in critically ill children, although recent studies have recognized their potential for harm. Translatability to pediatric acute respiratory distress syndrome is unknown given that hypoxemia has excluded pediatric acute respiratory distress syndrome patients from clinical trials. We aimed to determine whether an association exists between blood product transfusion and survival or duration of ventilation in pediatric acute respiratory distress syndrome.

DESIGN

Retrospective analysis of prospectively enrolled cohort.

SETTING

Large, academic PICU.

PATIENTS

Invasively ventilated children meeting Berlin Acute Respiratory Distress Syndrome and Pediatric Acute Lung Injury Consensus Conference Pediatric Acute Respiratory Distress Syndrome criteria from 2011 to 2015.

INTERVENTIONS

We recorded transfusion of RBC, fresh frozen plasma, and platelets within the first 3 days of pediatric acute respiratory distress syndrome onset. Each product was tested for independent association with survival (Cox) and duration of mechanical ventilation (competing risk regression with extubation as primary outcome and death as competing risk). A sensitivity analysis using 1:1 propensity matching was also performed.

MEASUREMENTS AND MAIN RESULTS

Of 357 pediatric acute respiratory distress syndrome patients, 155 (43%) received RBC, 82 (23%) received fresh frozen plasma, and 92 (26%) received platelets. Patients who received RBC, fresh frozen plasma, or platelets had higher severity of illness score, lower PaO2/FIO2, and were more often immunocompromised (all p < 0.05). Patients who received RBC, fresh frozen plasma, or platelets had worse survival and longer duration of ventilation by univariate analysis (all p < 0.05). After multivariate adjustment for above confounders, no blood product was associated with survival. After adjustment for the same confounders, RBC were associated with decreased probability of extubation (subdistribution hazard ratio, 0.65; 95% CI, 0.51-0.83). The association between RBC and prolonged ventilation was confirmed in propensity-matched subgroup analysis.

CONCLUSIONS

RBC transfusion was independently associated with longer duration of mechanical ventilation in pediatric acute respiratory distress syndrome. Hemoglobin transfusion thresholds should be tested specifically within pediatric acute respiratory distress syndrome to establish whether a more restrictive transfusion strategy would improve outcomes.

Trauma-Related Acute Lung Injury Develops Rapidly Irrespective of Resuscitation Strategy in the Rat

BACKGROUND

Acute lung injury (ALI) has been observed clinically after severe trauma. We have recently developed a rat model of polytrauma that shows evidence of multi-organ failure and coagulopathy. In this study, we investigate whether ALI occurs after severe trauma and resuscitation, and the cellular mechanisms involved.

METHODS

Polytrauma and hemorrhage was induced in anesthetized Sprague-Dawley rats. Five groups were prepared: control, no resuscitation, and resuscitation with Lactated Ringer (LR), fresh whole blood or whole blood stored 7days at 4°C. Resuscitation was begun 1 hr after trauma. Lung injury was determined by lung wet/dry weight ratios.

RESULTS

Polytrauma and hemorrhage (no resuscitation) led to a significant increase in the number of neutrophils, monocytes, macrophages, platelets, and the levels of myeloperoxidase, pro-inflammatory cytokines (IL-6, IL-1α, IL-1β), anti-inflammatory Th2 cytokines (IL-4, IL-10, IL-13), and chemokines (MIP-1α, GRO KC) in the lung tissue. Resuscitation with LR, fresh whole blood or stored blood led to a significant change in the lung wet/dry ratio signifying fluid movement into the lungs. However, fluid did not move into the lungs in non-resuscitated controls.

CONCLUSION

This study shows that trauma related acute lung injury occurs early after polytrauma and hemorrhage in rat. This ALI is secondary to the trauma, and likely due to an elevation in leukocytes, platelets, inflammatory cytokines and myeloperoxidase in the lung tissue prior to any resuscitation. Resuscitation with either LR or whole blood demonstrated similar lung edema. Blood was neither more protective nor more damaging than LR during early resuscitation.

Thrombocytopenia and Critical Care Medicine

Platelet transfusions play an important role in the treatment of critically ill patients. Like any blood component, however, there are various aspects of platelet transfusion therapy that need be considered by the intensivist. These include the proper dose and type of platelet component to infuse, as well as the route and method of administration. Methods to reduce the volume of the transfused platelets, for example, must ensure that the infused platelets will be functional and viable, posttransfusion. Treatment and diagnosis of the HLA alloimmunized recipient can pose a serious challenge to the clinician and an obstacle to adequate platelet therapy. An ICU patient for whom an adequate posttransfusion platelet increment cannot be achieved is at great risk of suffering a fatal hemorrhage. The ICU physician should be aware of the techniques used in modern transfusion practice to avoid having to deal with this complication. Adverse reactions to platelet transfusion include not only serologic ones, but those related to febrile and allergic complications, as well as infectious complications. The latter group includes diseases caused by infection with cytomegalovirus, bacteria, and a cadre of viruses including HIV and hepatitis. The clinical approach to thrombocytopenia in the ICU will be covered in some detail in an effort to review many of the conditions associated with recipient thrombocytopenia, including ITP, TTP, dilutional thrombocytopenia, DIC, surgery, HELLP syndrome, and drug-induced thrombocytopenia. Unfortunately the treatment approaches traditionally used are not always derived from evidence-based studies. This review covers many of these topics in an attempt to help physicians become better able to manage thrombocytopenia in the ICU and thus provide the best transfusion therapy for their patients.

Transfusion Related Acute Lung Injury (TRALI): A Single Institution Experience of 15 Years

Transfusion related acute Lung injury (TRALI) though a serious blood transfusion reaction with a fatality rate of 5-25 % presents with acute respiratory distress with hypoxaemia and noncardiac pulmonary oedema within 6 h of transfusion. In non fatal cases, it may resolve within 72 h or earlier. Although reported with an incidence of 1:5000, its true occurrence is rather unknown. Pathogenesis is believed to be related to sequestration and adhesion of neutrophils to the pulmonary capillary endothelium and its activation leading to its destruction and leaks. The patient's underlying condition, anti-neutrophil antibody in the transfused donor plasma and certain lipids that accumulate in routinely stores blood and components are important in its aetiopathogenesis. Patient's predisposing conditions include haematological malignancy, major surgery (especially cardiac), trauma and infections. The more commonly incriminated products include fresh frozen plasma (FFP), platelets (whole blood derived and apheresis), whole blood and Packed RBC. Occasional cases involving cryoprecipitate and Intravenous immunoglobulin (IVig) have also been reported. We present a 15 year single institution experience of TRALI, during which we observed 9 cases among 170,871 transfusions, giving an incidence of 1:19,000. We did not encounter cases of haematological malignancy or cardiac surgery in our TRALI patients. Among the blood products, that could be related to TRALI in our patients included solitary cases receiving cryoprecipitate, IVIg, and recombinant Factor VII apart from platelets and FFP. All patients were treated with oxygen support. Six patients required mechanical ventilation. Off label hydrocortisone was given to all patients. There were no cases of fatality among our patients.

Blood transfusions in cardiac surgery: indications, risks, and conservation strategies

Although red blood cell (RBC) transfusions are frequently used in cardiac operations, an increasing amount of data has demonstrated deleterious consequences. Consequently, the appropriate use of this limited resource is unclear. In this review, we discuss the relationship between anemia and the outcomes of cardiac surgical procedures, the risks associated with RBC transfusion, and the impact of blood transfusions on mortality and morbidity after cardiac operations. The review concludes with a discussion of randomized trials comparing restrictive versus liberal transfusion strategies and a consideration of blood conservation techniques.

Transfusion-related acute lung injury: advances in understanding the role of proinflammatory mediators in its genesis

Transfusion-related acute lung injury (TRALI) is the most common cause of serious morbidity and mortality due to hemotherapy. The pathogenesis is the result of two events: the first related to the recipient's clinical condition, predisposing to acute lung injury (ALI) through neutrophil or polymorphonuclear leukocyte sequestration, and the second being the infusion of antibodies or mediators that activate these adherent polymorphonuclear neutrophils, resulting in endothelial damage, capillary leak and ALI. TRALI is most prevalent in the critically ill, although many of these cases are termed ALI. Although mitigation strategies, such as the use of male-only plasma, have decreased the number of TRALI cases and deaths, TRALI still occurs. This review will detail the pathophysiology of TRALI, provide insight into newer areas of research and critically assess current practices to mitigate TRALI and improve transfusion safety.

Therapeutic options for transfusion related acute lung injury; the potential of the G2A receptor

Priming of polymorphonuclear leukocytes (PMNs) enhances their adhesion to endothelium, the release of their granule content and their production of reactive oxygen species. These effects are etiological in transfusion related acute lung injury (TRALI) and many clinically important mediators of TRALI prime PMNs. A priming activity that develops over time in stored blood products has been shown to be due to the accumulation of lysophospatidylcholines (lyso-PCs) and has been found to be related clinically to TRALI. Lyso- PCs prime PMNs activating the G2A receptor and several inhibitors of this receptor, which could potentially be therapeutic in TRALI, have been identified. Recent work has described early steps in the signaling from the G2A receptor which has revealed potential targets for novel antagonists of lyso-PC mediated priming via G2A. Additionally, characterization of the process by which lyso-PCs are generated in stored blood products could allow development of inhibitors and additive solutions to block their formation in the first place.

The pro-inflammatory effects of platelet contamination in plasma and mitigation strategies for avoidance

BACKGROUND AND OBJECTIVES

Plasma and platelet concentrates are disproportionately implicated in transfusion-related acute lung injury (TRALI). Platelet-derived pro-inflammatory mediators, including soluble CD40 ligand (sCD40L), accumulate during storage. We hypothesized that platelet contamination induces sCD40L generation that causes neutrophil [polymorphonuclear leucocyte (PMN)] priming and PMN-mediated cytotoxicity.

MATERIALS AND METHODS

Plasma was untreated, centrifuged (12,500 g) or separated from leucoreduced whole blood (WBLR) prior to freezing. Platelet counts and sCD40L concentrations were measured 1-5 days post-thaw. The plasma was assayed for PMN priming activity and was used in a two-event in vitro model of PMN-mediated human pulmonary microvascular endothelial cell (HMVEC) cytotoxicity.

RESULTS

Untreated plasma contained 42±4·2×10(3)/μl platelets, which generated sCD40L accumulation (1·6-eight-fold vs. controls). Priming activity and HMVEC cytotoxicity were directly proportional to sCD40L concentration. WBLR and centrifugation reduced platelet and sCD40L contamination, abrogating the pro-inflammatory potential.

CONCLUSION

Platelet contamination causes sCD40L accumulation in stored plasma that may contribute to TRALI. Platelet reduction is potentially the first TRALI mitigation effort in plasma manufacturing.

TRALI-new challenges for histocompatibility and immunogenetics in transfusion medicine

Antibodies against human leukocyte antigens (HLAs) have long been associated with transfusion-related acute lung injury (TRALI). In contrast to febrile transfusion reactions and refractoriness to platelet transfusions in immunized patients, the causative antibodies in TRALI are present in the transfused blood component, i.e. they are formed by the blood donor and not by the recipient. Consequently, blood components with high plasma volume are particularly associated with TRALI. In addition to antibodies against HLAs, antibodies directed against human neutrophil antigens (HNAs) present in the plasma of predominantly multiparous female blood donors can induce severe TRALI reactions. Especially, antibodies to HLA class II and HNA-3a antigens can induce severe or even fatal ALI in critically ill patients. Over the last decade, the clinical importance of TRALI as major cause for severe transfusion-related morbidities has led to the establishment of new guidelines aimed at preventing this condition, including routine testing for HLA and -HNA antibodies for plasma donors with a history of allogeneic sensitization. This, in turn, poses new challenges for close collaboration between blood transfusion centers and histocompatibility and immunogenetics laboratories, for sensitive and specific detection of the relevant antibodies.

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.

The role of neutrophils in the pathogenesis of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is the major cause of transfusion related morbidity and mortality, world wide. Efforts to reduce or eliminate this serious complication of blood transfusion are hampered by an incomplete understanding of its pathogenesis. Currently, TRALI is thought to be mediated by donor alloantibodies directed against host leukocytes or the result of 2 distinct clinical events. For both proposed mechanisms, the neutrophil is the key effector cell. This article reviews TRALI pathophysiology, explores the role of the neutrophil, details practical information for appropriate diagnosis and promotes further studies into the pathogenesis of TRALI.

Rapid screening of granulocyte antibodies with a novel assay: flow cytometric granulocyte immunofluorescence test

BACKGROUND

White blood cell (WBC)-associated antibodies can lead to severe pulmonary transfusion reactions (transfusion-related acute lung injury [TRALI]). Investigation of a large number of blood donor samples using the standard granulocyte immunofluorescence test (GIFT) and granulocyte agglutination test (GAT) proved to be difficult to perform due to the time-consuming process and the large quantity of test cells required. This study describes the novel flow cytometric GIFT (Flow-GIFT) method for a rapid detection of granulocyte antibodies by flow cytometric analysis.

STUDY DESIGN AND METHODS

A total of 141 sera were analyzed for the presence of granulocyte antibodies that were previously associated with suspected TRALI. As test cells whole blood samples from human neutrophil antigen (HNA)-typed donors were isolated using cell sedimentation in a ficoll density gradient. WBCs were incubated with the respective serum and binding of antibodies to the test cells was detected using fluorescein isothiocyanate-conjugated anti-human antibody. Standard GIFT and GAT were performed as reference methods.

RESULTS

Seven sera containing anti-HNA-3a, CD16, and HLA Class I were negative in the standard GIFT and eight sera containing anti-HNA-2a, anti-CD16, and anti-HLA Class I were not detected in the GAT. The novel Flow-GIFT was able to detect all granulocyte antibodies, which were only detectable in a combination of standard GIFT and GAT. In serial dilution tests, the Flow-GIFT detected the antibodies at higher dilutions than the reference methods GIFT and GAT.

CONCLUSION

The Flow-GIFT method permits rapid detection of granulocyte antibodies requiring fewer donor test cells. This method is ideal for automation and will potentially open the way for screening of granulocyte antibodies in a large donor population.

Transfusion-related acute lung injury (TRALI): current concepts and misconceptions

Transfusion-related acute lung injury (TRALI) is the most common cause of serious morbidity and mortality due to hemotherapy. Although the pathogenesis has been related to the infusion of donor antibodies into the recipient, antibody negative TRALI has been reported. Changes in transfusion practices, especially the use of male-only plasma, have decreased the number of antibody-mediated cases and deaths; however, TRALI still occurs. The neutrophil appears to be the effector cell in TRALI and the pathophysiology is centered on neutrophil-mediated endothelial cell cytotoxicity resulting in capillary leak and ALI. This review will detail the pathophysiology of TRALI including recent pre-clinical data, provide insight into newer areas of research, and critically assess current practices to decrease it prevalence and to make transfusion safer.

Transfusion-related acute lung injury: a rare and life-threatening complication of a common procedure

Transfusion-related acute lung injury (TRALI) has emerged as one of the leading causes of transfusion-related morbidity and mortality and is undoubtedly under diagnosed. It is a serious pulmonary syndrome that can lead to death if not recognised and treated promptly. The diagnosis of TRALI is based primarily upon clinical signs and symptoms and is, in part, a diagnosis of exclusion.

Fatal transfusion related acute lung injury following coronary artery by-pass surgery: a case report

Background

Transfusion related acute lung injury (TRALI) is a potentially fatal Acute Lung Injury following transfusion of blood components. Hypotheses implicate donor-derived anti-human leukocyte antigen or granulocyte antibodies reacting with recipients' leukocytes, releasing inflammatory mediators. Lack of agreement on underlying cellular and molecular mechanisms renders improving transfusion safety difficult and expensive.

Case Presentation

Literature search has not revealed any case of TRALI from Pakistan. We report the case of fatal TRALI in a 68 year old male who received blood products after coronary artery by-pass surgery.

Conclusion

This article aims to create awareness about this complication and suggests that post transfusion cardiopulmonary instability should alert to the possibility of TRALI.

The impact of clinical risk factors in the conversion from acute lung injury to acute respiratory distress syndrome in severe multiple trauma patients

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are different stages of the same disease, the aggravated stage of ALI leading to ARDS. Patients with ARDS have higher hospital mortality rates and reduced long-term pulmonary function and quality of life. It is, therefore, important to prevent ALI converting to ARDS. This study evaluated 17 risk factors potentially associated with the conversion from ALI to ARDS in severe multiple trauma. The results indicate that the impact of pulmonary contusion, APACHE II score, gastrointestinal haemorrhage and disseminated intravascular coagulation may help to predict conversion from ALI to ARDS in the early phase after multiple-trauma injury. Trauma duration, in particular, strongly impacted the short- and long-term development of ALI. Being elderly (aged > or = 65 years) and undergoing multiple blood transfusions in the early phase were independent risk factors correlated with secondary sepsis, deterioration of pulmonary function and transfusion-related acute lung injury due to early multiple fluid resuscitation.

Estimating the cost of blood: past, present, and future directions

Understanding the costs associated with blood products requires sophisticated knowledge about transfusion medicine and is attracting the attention of clinical and administrative healthcare sectors worldwide. To improve outcomes, blood usage must be optimized and expenditures controlled so that resources may be channeled toward other diagnostic, therapeutic, and technological initiatives. Estimating blood costs, however, is a complex undertaking, surpassing simple supply versus demand economics. Shrinking donor availability and application of a precautionary principle to minimize transfusion risks are factors that continue to drive the cost of blood products upward. Recognizing that historical accounting attempts to determine blood costs have varied in scope, perspective, and methodology, new approaches have been initiated to identify all potential cost elements related to blood and blood product administration. Activities are also under way to tie these elements together in a comprehensive and practical model that will be applicable to all single-donor blood products without regard to practice type (e.g., academic, private, multi- or single-center clinic). These initiatives, their rationale, importance, and future directions are described.

Detection of anti-CD32 alloantibody in donor plasma implicated in development of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) occasionally causes serious symptoms that may be fatal to recipients. Polymorphonuclear neutrophils (PMNs) and alloantibodies specific to PMN cell surface antigens are suspected to cause TRALI. The aim of this study is to establish a sensitive and stable procedure of detecting alloantibodies not only in donor blood, but also in recipient's plasma. We have introduced a new method of detecting alloantibodies based on double-determinant enzyme-linked immunosorbent assay (DD-ELISA) and a monoclonal antibody-immobilized granulocyte antigen (MAIGA) test (arbitrarily designated as modified DD-ELISA). We verified the specificity of alloantibodies against PMN cell surface antigens in plasma samples from three normal healthy donors of blood that induced respiratory distress in recipients after a blood transfusion. Anti-CD32 (Fc gamma RIII) alloantibodies were detected in all the plasma samples using two different clones of the monoclonal anti-CD32 antibody. The specificities of these plasma samples could not be identified by the granulocyte immunofluorescence test (GIFT) using typed test cells. Except for the anti-CD32 alloantibodies, one plasma sample was proved to have the anti-HNA-1a alloantibodies. In another plasma sample, the anti-HNA-2a alloantibodies were detected. By modified DD-ELISA, we could clearly specify the presence of alloantibodies in the three plasma samples. Our results also suggest that the anti-CD32 alloantibodies can be generated in vivo and may play some roles in the development of TRALI.

[Transfusion-related acute lung injury]

OBJECTIVES

The transfusion-related acute lung injury frequency was for a long time underestimated since it lacked both a widely accepted clinical definition and a comprehensive etiologic description. Recent clinical and biological data have underlined its frequency and have allowed a better understanding of its mechanisms.

CURRENT KNOWLEDGE AND KEY POINTS

Trali is an interstitial lung injury occurring within 6 hours after the beginning of a blood transfusion. This time relationship between blood injection and the occurrence of lung edema is sufficient for a positive diagnosis, if any other cause of interstitial lung edema have been excluded. The clinical definition relies on a desaturation of arterial blood associated to a lack of any cardiac failure or circulation overload. The link between transfusion and lung edema is not univocal and several categories of mechanisms have been discussed. At least 2 of them are well identified; the first one is an immune conflict, and the second one is an activation of neutrophils by injection of biological modifiers such as lipids or CD40 soluble ligand. Evidences exist for the occurrence of Trali only in predisposing condition that mostly consists of a preceding leucostase in lung capillaries. Trali is treated like other lung interstitial edema by oxygen therapy and mechanical ventilation.

FUTURE PROJECTS

A better knowledge of Trali offers the opportunity of improving the understanding of the role of blood transfusion in lung edema occurring in complex situations and open the way for a better definition of at risk patient and at risk blood components.

Transfusion-related acute lung injury in patients with burns

Transfusion-related acute lung injury (TRALI) has not been systematically described in patients with burn injury, and the characterization of TRALI in patients with pre-existing acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) also is lacking. Our aim was to identify TRALI in burn patients and to attempt to characterize transfusion (TXN)-related pulmonary deterioration in burn patients with pre-existing ALI or ARDS. We undertook a retrospective review of mechanically ventilated and transfused burn patients at an adult regional burn center between January 1, 2003, and January 5, 2005. A blinded intensivist independently rated pre- and post-TXN chest radiographs (CXRs). There were 25 patients (age 51 +/- 19 years, %TBSA burns 30 +/- 19, full thickness %BSA 17 +/- 19, with a 24% incidence of smoke inhalation) who received 124 TXNs. New ALI developed within 6 hours after four TXNs. In one TXN, there were no other precipitating causes (eg, infection, inhalation injury), suggesting possible TRALI (incidence 0.8%). Existing ALI or ARDS was present before 63 (51%) of the TXNs. Definite worsening of the CXR and deterioration in the PaO2/FiO2 ratio (18% +/- 4%) within 6 hours of TXN occurred after six transfusions. In two of the TXNs, there were no other precipitating causes, suggesting possible TXN-related pulmonary deterioration (incidence 3.2%). Vigilance must be maintained for TRALI in burn patients. For patients with existing ALI or ARDS, we suggest that worsening of the CXR and reduction in the PaO2/FiO2 ratio by 20% or more within 6 hours of transfusion should be investigated for possible TRALI with appropriate donor investigations.

Transfusion-related acute lung injury: a literature review

Transfusion-related acute lung injury (TRALI) is a serious and potentially fatal complication of transfusion of blood and blood components. TRALI is under-diagnosed and under-reported because of a lack of awareness. A number of models have been proposed to explain the pathogenesis of TRALI: an antibody mediated model; a two-event biologically active mediator model; and a combined model. TRALI can occur with any type of blood product and can occur with as little as one unit. Its presentation is similar to other forms of acute lung injury and management is predominantly supportive. The main strategy in combating TRALI is prevention both through manipulation of the donor pool and through clinical strategies directed at reducing transfusion of blood products including, but not limited to, evidence-based lower transfusion thresholds. This article presents a review of TRALI and addresses the definition, pathology, pathogenesis, clinical manifestations, treatment and prevention of the syndrome.

Transfusion-Related Acute Lung Injury (TRALI): Current Clinical and Pathophysiologic Considerations

Transfusion-related acute lung injury (TRALI) is a rare transfusion reaction presenting as respiratory distress during or after transfusion of blood products. TRALI varies in severity, and mortality is not uncommon. TRALI reactions have equal gender distributions and can occur in all age groups. All blood products, except albumin, have been implicated in TRALI reactions. TRALI presents as acute respiratory compromise occurring in temporal proximity to a transfusion of a blood product. Other causes of acute lung injury should be excluded in order to definitively diagnose TRALI. Clinically and pathologically, TRALI mimics acute respiratory distress syndrome (ARDS), with neutrophil-derived inflammatory chemokines and cytokines believed to be involved in the pathogenesis of both entities. Anti-HLA and anti-neutrophil antibodies have been implicated in some cases of TRALI. Treatment for TRALI is supportive; prevention is important. It is suspected that TRALI is both underdiagnosed and underreported. One of the difficulties in the evaluation of potential TRALI reactions is, until recently, the lack of diagnostic criteria. A group of transfusion medicine experts, the American-European Consensus Conference (AECC), recently met and developed diagnostic criteria of TRALI, as well as recommendations for management of donors to prevent future TRALI reactions. In light of the AECC consensus recommendations, we report an incident of TRALI in an oncology patient as an example of the potential severity of the lung disease and the clinical and laboratory evaluation of the patient. We also review the literature on this important complication of blood transfusion that internists may encounter.

The two-event model of transfusion-related acute lung injury

The objective of this review is to present the two-event model of transfusion-related acute lung injury (TRALI), a life-threatening complication of transfusions that has been the most common cause of transfusion-related death over the past 2 yrs in the United States. The two-event model of TRALI, which is identical to the pathogenesis of the acute respiratory distress syndrome (ARDS), is reviewed and contrasted to antibody-mediated TRALI. Laboratory studies, both in vitro and in vivo, are discussed as well as human studies of TRALI. Methods to avoid patient exposure to blood components that may cause TRALI are also discussed.

Blood donor and component management strategies to prevent transfusion-related acute lung injury (TRALI)

OBJECTIVE

Discuss the pros and cons of using donor and blood product-management strategies to prevent transfusion-related acute lung injury (TRALI).

DATA SOURCE

A review of the literature was performed.

RESULTS

Despite therapeutic advances in pulmonary and critical care medicine, TRALI is now considered to be one of the leading causes of transfusion-associated mortality, and thus determining how to prevent TRALI is extremely important. Donor and product-management strategies to prevent this life-threatening condition have been suggested, but because of gaps in our understanding of TRALI, blood-bankers do not know how beneficial these interventions will be, nor the amount of potential harm-such as decreasing the availability of blood-that could arise if they were implemented. This article discusses the advantages and disadvantages of the various preventive measures that have been described in the literature.

CONCLUSIONS

Preventing TRALI poses a difficult challenge for blood-banking experts, because it is unknown which measures will be effective in decreasing the incidence of TRALI and which could have significant drawbacks. Only additional research into TRALI prevention will provide the answers on how to best protect patients from this potentially fatal reaction.

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.

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.

Structural organization of the neutrophil NADPH oxidase: phosphorylation and translocation during priming and activation

The reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is part of the microbicidal arsenal used by human polymorphonuclear neutrophils (PMNs) to eradicate invading pathogens. The production of a superoxide anion (O2-) into the phagolysosome is the precursor for the generation of more potent products, such as hydrogen peroxide and hypochlorite. However, this production of O2- is dependent on translocation of the oxidase subunits, including gp91phox, p22phox, p47phox, p67phox, p40phox, and Rac2 from the cytosol or specific granules to the plasma membrane. In response to an external stimuli, PMNs change from a resting, nonadhesive state to a primed, adherent phenotype, which allows for margination from the vasculature into the tissue and chemotaxis to the site of infection upon activation. Depending on the stimuli, primed PMNs display altered structural organization of the NADPH oxidase, in that there is phosphorylation of the oxidase subunits and/or translocation from the cytosol to the plasma or granular membrane, but there is not the complete assembly required for O2- generation. Activation of PMNs is the complete assembly of the membrane-linked and cytosolic NADPH oxidase components on a PMN membrane, the plasma or granular membrane. This review will discuss the individual components associated with the NADPH oxidase complex and the function of each of these units in each physiologic stage of the PMN: rested, primed, and activated.

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

BACKGROUND AND OBJECTIVE

Transfusion of blood components can trigger immunological reactions which may result in a transfusion-related acute lung injury (TRALI). The reported incidence is low; however, there is increasing evidence that the true incidence of this complication may be much higher. One reason for underdiagnosing TRALI could be a deficiency of knowledge about this complication. Therefore, we studied the level of knowledge concerning TRALI among clinicians working on intensive care units (ICU) of an university teaching hospital.

METHODS

A total of 65 clinicians were asked to complete a confidential questionnaire designed to evaluate their knowledge about incidence, pathophysiology, clinical symptoms, therapy and outcome of TRALI. This questionnaire consisted of 13 questions which could be assessed by 'yes', 'no' or 'do not know'.

RESULTS

Only 42 +/- 18% (mean +/- SD) of all answers were correct, while 33 +/- 17% were wrong and 25 +/- 8% unanswered ('do not know'). The 95% confidence interval for the correct answers was 30.8-53.8% implying that there was no significant difference compared to the probability of arbitrary guessing (33.3%).

CONCLUSIONS

Our survey uncovered a marked deficit of knowledge about TRALI suggesting that the low reported incidence of this complication may be in part due to a lack of awareness for TRALI. We conclude that training programmes for clinicians should alert them to the symptoms, diagnosis and treatment options of TRALI.

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.

Acute and transient decrease in neutrophil count in transfusion-related acute lung injury: cases at one hospital

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a rare but serious complication of blood transfusion. The syndrome is characterized by new acute lung injury developing during or within 6 hours of blood transfusion.

STUDY DESIGN AND METHODS

The study design was observational in nature.

RESULTS

All three cases of TRALI were associated with acute but transient decrease in the white blood cell (WBC) count. Implicated donors had HLA antibodies that matched the recipients' HLA antigens. The implicated units were a plateletpheresis in one case and fresh frozen plasma units in the other two. All implicated donors were multiparous women. The implicated antibody specificities were anti-HLA Class I and Class II in one case and anti-HLA Class II in the other two cases. Interestingly, patient neutrophil counts decreased by 80 to 90 percent in all three cases, including the two cases associated with HLA Class II antibodies.

CONCLUSION

An acute and transient decrease in WBC count may be a previously underrecognized feature of TRALI. A drop in the neutrophil count can occur even when the implicated antibodies have specificities to HLA Class II antigens, although they are expressed only on stimulated neutrophils. Based on the observations in these cases, it is recommended that a complete blood count and differential be obtained when TRALI is suspected. Further investigations into the mechanisms of the decrease in circulating neutrophils that is associated with infusion of HLA Class II antibody may yield new insights into the mechanism of TRALI.

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.

Optimizing platelet transfusion therapy

Platelet transfusions are widely used. Prophylactic transfusions are employed in severely thrombocytopenic patients without evidence of bleeding, but no randomized trial data prove the safety or efficacy of this approach. Randomized trials have demonstrated the equivalence of transfusion triggers of 10,000 and 20,000/microl for prophylactic transfusions. The former threshold is potentially safer for the patient, conservative of donor resources and leads to lower costs, with perhaps a slightly greater risk of minor hemorrhage. Randomized trials have demonstrated the equivalence of pheresis or whole blood-derived platelet transfusions. The former present a lower risk for infectious agents, and the latter are less expensive and a more efficient use of limited donor resources. Randomized trials prove that leukoreduced and ABO identical platelet transfusions reduce the risks of HLA alloimmunization and platelet transfusion refractoriness (both leukoreduction and ABO matching), transfusion reactions (leukoreduction) and CMV transmission (leukoreduction). Leukoreduction and ABO matching of platelet transfusions also have been associated in preliminary observational studies with reduced morbidity and mortality in surgical patients and reduced infections in patients with leukemia. These results require further investigation. Future challenges include (1) determining the best approach to bacterial contamination of platelets, whether by detection methods or pathogen inactivation and (2) determining the threshold for prophylactic platelet transfusions in thrombocytopenic patients undergoing surgery or invasive procedures.

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.

Current concepts and issues in blood management

Blood management in orthopedic surgery is no longer an option; it is a requirement. The combination of patient desire to avoid transfusion, increasing evidence of multiple risks, decreasing blood supplies, and increasing costs mandate attention. This article addresses the balance of risk versus benefit in blood transfusion and presents a perioperative plan of blood management for patients undergoing orthopedic surgery.

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.

TRALI after the transfusion of cross-match-positive granulocytes

BACKGROUND

TRALI is a serious complication of transfusion. WBC antibodies have been associated with TRALI. The importance of such antibodies for the transfusion of granulocytes is unknown.

CASE REPORT

A patient with hematologic malignancy and neutropenia-associated pneumonitis received 2 units of granulocytes despite a positive serologic cross- match. She developed severe TRALI after the second transfusion.

RESULTS

The recipient's serum was reactive with immobilized HLA class I antigens from donor cells in a glycoprotein-specific assay. With an absorption-elution technique, at least anti-HLA-A2 could be identified as one of the donor-reactive antibodies in the recipient's serum.

CONCLUSION

Granulocyte-reactive antibodies are associated with TRALI in an alloimmunized patient receiving granulocyte transfusions. Performing a cross-match procedure may be helpful in preventing severe pulmonary reactions. Additional data are required to determine whether cross-matching as a regular practice in granulocyte transfusions would be beneficial for patients.