Recipient clinical risk factors predominate in possible transfusion-related acute lung injury

Smoking on the risk of acute respiratory distress syndrome: a systematic review and meta-analysis

BACKGROUND

The relationship between smoking and the risk of acute respiratory distress syndrome (ARDS) has been recognized, but the conclusions have been inconsistent. This systematic review and meta-analysis investigated the association between smoking and ARDS risk in adults.

METHODS

The PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched for eligible studies published from January 1, 2000, to December 31, 2023. We enrolled adult patients exhibiting clinical risk factors for ARDS and smoking condition. Outcomes were quantified using odds ratios (ORs) for binary variables and mean differences (MDs) for continuous variables, with a standard 95% confidence interval (CI).

RESULTS

A total of 26 observational studies involving 36,995 patients were included. The meta-analysis revealed a significant association between smoking and an increased risk of ARDS (OR 1.67; 95% CI 1.33-2.08; P < 0.001). Further analysis revealed that the associations between patient-reported smoking history and ARDS occurrence were generally similar to the results of all the studies (OR 1.78; 95% CI 1.38-2.28; P < 0.001). In contrast, patients identified through the detection of tobacco metabolites (cotinine, a metabolite of nicotine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a metabolite of tobacco products) showed no significant difference in ARDS risk (OR 1.19; 95% CI 0.69-2.05; P = 0.53). The smoking group was younger than the control group (MD - 7.15; 95% CI - 11.58 to - 2.72; P = 0.002). Subgroup analysis revealed that smoking notably elevated the incidence of ARDS with extrapulmonary etiologies (OR 1.85; 95% CI 1.43-2.38; P < 0.001). Publication bias did not affect the integrity of our conclusions. Sensitivity analysis further reinforced the reliability of our aggregated outcomes.

CONCLUSIONS

There is a strong association between smoking and elevated ARDS risk. This emphasizes the need for thorough assessment of patients' smoking status, urging healthcare providers to vigilantly monitor individuals with a history of smoking, especially those with additional extrapulmonary risk factors for ARDS.

Platelet extracellular vesicles and their mitochondrial content improve the mitochondrial bioenergetics of cellular immune recipients

BACKGROUND

Mitochondria play a critical role in the production of cell energy and the regulation of cell death. Therefore, mitochondria orchestrate numerous cell effector functions, including fine-tuning the immune system. While mitochondria are mainly found intracellularly, they can escape the confine of the cell during the process of extracellular vesicle release. Platelets patrol blood vessels to ensure vasculature integrity and to support the immune system. In blood, platelets are the primary source of circulating mitochondria. Activated platelets produce extracellular vesicles, including a subset of mitochondria-containing vesicles.

STUDY DESIGN AND METHODS

We characterized mitochondrial functions in platelet-derived extracellular vesicles, and examined whether they could impact the bioenergetics of cellular immune recipients using an extracellular flux analyzer to measure real-time bioenergetics.

RESULTS

We validated that extracellular vesicles derived from activated platelets contain the necessary mitochondrial machinery to respirate and generate energy. Moreover, neutrophils and monocytes efficiently captured platelet-derived extracellular vesicles, enhancing their mitochondrial fitness. This process required functional mitochondria from donor platelets, as it was abolished by the inactivation of extracellular mitochondria using mitochondrial poison.

DISCUSSION

Together, the data suggest that extracellular mitochondria produced by platelets may support other metabolic functions through transcellular bioenergetics.

Noninfectious Pulmonary Complications after Hematopoietic Stem Cell Transplantation

Pulmonary complications after hematopoietic stem cell transplantation (HSCT) are important sources of morbidity and mortality. Improvements in infection-related complications have made noninfectious pulmonary complications an increasingly significant driver of transplantation-related mortality. Broadly, these complications can be characterized as either early or late complications, with idiopathic pneumonia syndrome and bronchiolitis obliterans syndrome the most prevalent early and late complications, respectively. Outcomes with historical treatment consisting mainly of corticosteroids are often poor, highlighting the need for a deeper understanding of these complications' underlying disease biology to guide the adoption of novel therapies that are being increasingly used in the modern era.

Transfusion-Related Acute Lung Injury (TRALI) in Postoperative Anesthesia Care Unit (PACU) After One Unit of Platelets: A Case Report

Transfusion-related acute lung injury (TRALI) following transfusion of all plasma-containing blood products is a rare but serious syndrome characterized by the acute onset of non-cardiogenic pulmonary edema with severe hypoxemia with or without symptoms of hypotension, pinkish frothy secretions, fever, and cyanosis. In this report, we present a case of a 66-year-old female with a medical history significant for hypertension, hyperlipidemia, hepatitis C, liver cirrhosis, tobacco use disorder, metastatic spindle cell carcinoma of the lung status post chemotherapy who developed TRALI after administration of one unit of platelets. Although a rare occurrence, there can be a considerable risk of TRALI following transfusion of all plasma-containing blood products and there is great importance in considering each patient’s risk factors for TRALI development prior to blood product administration.

Transfusion-Related Acute Lung Injury: 36 years of Progress (1985-2021)

The term transfusion-related acute lung injury (TRALI) was coined in 1985 to describe acute respiratory distress syndrome (ARDS) after transfusion, when another ARDS risk factor was absent; TRALI cases were mostly associated with donor leukocyte antibody. In 2001, plasma from multiparous donors was implicated in TRALI in a randomized controlled trial in Sweden. In 2003 and in many years thereafter, the FDA reported that TRALI was the leading cause of death from transfusion in the United States. In 2003, the United Kingdom was the first among many countries to successfully reduce TRALI using male-predominant plasma. These successes are to be celebrated. Nevertheless, questions remain about the mechanisms of non-antibody TRALI, the role of blood products in the development of ARDS in massive transfusion patients, the causes of unusual TRALI cases, and how to reduce inaccurate clinical diagnoses of TRALI in clinical practice. Regarding the latter, a study in 2013-2015 at 169 US hospitals found that many TRALI diagnoses did not meet clinical definitions. In 2019, a consensus panel established a more precise terminology for clinical diagnosis: TRALI type I and TRALI type II are cases where transfusion is the likely cause, and ARDS are cases where transfusion is not the likely cause. For accurate diagnosis using these clinical definitions, critical care expertise is needed to distinguish between permeability versus hydrostatic pulmonary edema, to determine whether an ARDS risk factor is present and, if so, whether respiratory function was stable within the 12 hours before transfusion.

Risk Factors for Transfusion-Related Acute Lung Injury

BACKGROUND

Until now, transfusion-related acute lung injury (TRALI) has been considered the leading cause of blood transfusion-related diseases and death. In addition, there is no clinically effective treatment plan for TRALI. The aim of this study was to systematically summarize the literature on risk factors for TRALI in critical patients.

METHODS

Electronic searches (up to March 2020) were performed in the Cochrane Library, Web of Knowledge, Embase, and PubMed databases. We included studies reporting on the risk factors of TRALI for critical patients and extracted risk factors. A total of 13 studies met the inclusion criteria.

RESULTS

We summarized and analyzed the potential risk factors of TRALI for critical patients in 13 existing studies. Host-related factors were age (odds ratio [OR] 1.16 [95% CI 1.08-1.24]), female sex (OR 1.26 [95% CI 1.16-1.38]), tobacco use status (OR 3.82 [95% CI 1.91-7.65]), chronic alcohol abuse (OR 3.82 [95% CI 2.97-26.83]), positive fluid balance (OR 1.24 [95% CI 1.08-1.42]), shock before transfusion (OR 4.41 [95% CI 2.38-8.20]), and American Society of Anesthesiologists (ASA) score of the recipients (OR 2.72 [95% CI 1.43-5.16]). The transfusion-related factors were the number of transfusions (OR 1.40 [95% CI 1.14-1.72]) and units of fresh frozen plasma (OR 1.21 [95% CI 1.01-1.46]). The device-related factor was mechanical ventilation (OR 4.13 [95% CI 2.20-7.76]).

CONCLUSIONS

The risk factors that were positively correlated with TRALI in this study included number of transfusions and units of fresh frozen plasma. Age, female sex, tobacco use, chronic alcohol abuse, positive fluid balance, shock before transfusion, ASA score, and mechanical ventilation may be potential risk factors for TRALI. Our results suggest that host-related risk factors may play a more important role in the occurrence and development of TRALI than risk factors related to blood transfusions.

NT-proBNP levels in the identification and classification of pulmonary transfusion reactions

BACKGROUND

Consensus definitions for transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) have recently been revised; however, pulmonary transfusion reactions remain difficult to diagnose. We hypothesized that N-terminal pro-brain natriuretic peptide (NT-proBNP) levels could have utility in the identification and classification of pulmonary transfusion reactions.

STUDY DESIGN AND METHODS

We performed a secondary analysis of a case-control study of pulmonary transfusion reactions at four academic hospitals. We evaluated clinical data and measured NT-proBNP levels prior to and following transfusion in patients with TACO (n = 160), transfused acute respiratory distress syndrome (ARDS) [n = 51], TRALI [n = 12], TACO/TRALI [n = 7], and controls [n = 335]. We used Wilcoxon Rank-Sum tests to compare NT-proBNP levels, and classification and regression tree (CART) algorithms to produce a ranking of covariates in order of relative importance for differentiating TACO from transfused controls.

RESULTS

Pre-transfusion NT-proBNP levels were elevated in cases of transfused ARDS and TACO (both P < .001) but not TRALI (P = .31) or TACO/TRALI (P = .23) compared to transfused controls. Pre-transfusion NT-proBNP levels were higher in cases of transfused ARDS or TRALI with a diagnosis of sepsis compared to those without (P < .05 for both). CART analyses resulted in similar differentiation of patients with TACO from transfused controls for models utilizing either NT-proBNP levels (AUC 0.83) or echocardiogram results (AUC 0.80).

CONCLUSIONS

NT-proBNP levels may have utility in the classification of pulmonary transfusion reactions. Prospective studies are needed to test the predictive utility of pre-transfusion NT-proBNP in conjunction with other clinical factors in identifying patients at risk of pulmonary transfusion reactions.

Risk modifiers of acute respiratory distress syndrome in patients with non-pulmonary sepsis: a retrospective analysis of the FORECAST study

Background

Predisposing conditions and risk modifiers instead of causes and risk factors have recently been used as alternatives to identify patients at a risk of acute respiratory distress syndrome (ARDS). However, data regarding risk modifiers among patients with non-pulmonary sepsis is rare.

Methods

We conducted a secondary analysis of the multicenter, prospective, Focused Outcomes Research in Emergency Care in Acute Respiratory Distress Syndrome, Sepsis and Trauma (FORECAST) cohort study that was conducted in 59 intensive care units (ICUs) in Japan during January 2016–March 2017. Adult patients with severe sepsis caused by non-pulmonary infection were included, and the primary outcome was having ARDS, defined as meeting the Berlin definition on the first or fourth day of screening. Multivariate logistic regression modeling was used to identify risk modifiers associated with ARDS, and odds ratios (ORs) and their 95% confidence intervals were reported. The following explanatory variables were then assessed: age, sex, admission source, body mass index, smoking status, congestive heart failure, chronic obstructive pulmonary disease, diabetes mellitus, steroid use, statin use, infection site, septic shock, and acute physiology and chronic health evaluation (APACHE) II score.

Results

After applying inclusion and exclusion criteria, 594 patients with non-pulmonary sepsis were enrolled, among whom 85 (14.3%) had ARDS. Septic shock was diagnosed in 80% of patients with ARDS and 66% of those without ARDS (p = 0.01). APACHE II scores were higher in patients with ARDS [26 (22–33)] than in those without ARDS [21 (16–28), p < 0.01]. In the multivariate logistic regression model, the following were independently associated with ARDS: ICU admission source [OR, 1.89 (1.06–3.40) for emergency department compared with hospital wards], smoking status [OR, 0.18 (0.06–0.59) for current smoking compared with never smoked], infection site [OR, 2.39 (1.04–5.40) for soft tissue infection compared with abdominal infection], and APACHE II score [OR, 1.08 (1.05–1.12) for higher compared with lower score].

Conclusions

Soft tissue infection, ICU admission from an emergency department, and a higher APACHE II score appear to be the risk modifiers of ARDS in patients with non-pulmonary sepsis.

Contemporary Risk Factors and Outcomes of Transfusion-Associated Circulatory Overload

OBJECTIVES

Transfusion-associated circulatory overload is characterized by hydrostatic pulmonary edema following blood transfusion. Restrictive transfusion practice may affect the occurrence and severity of transfusion-associated circulatory overload in critically ill patients. We sought to examine contemporary risk factors and outcomes for transfusion-associated circulatory overload.

DESIGN

Case-control study.

SETTING

Four tertiary care hospitals.

PATIENTS

We prospectively enrolled 200 patients with transfusion-associated circulatory overload identified by active surveillance and 405 controls matched by transfusion intensity.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Among 20,845 transfused patients who received 128,263 blood components from May 2015 until July 2016, transfusion-associated circulatory overload incidence was one case per 100 transfused patients. In addition to cardiovascular comorbidities, multivariable analysis identified the following independent predictors of transfusion-associated circulatory overload: acute kidney injury, emergency surgery, pretransfusion diuretic use, and plasma transfusion-the latter especially in females. Compared with matched controls, transfusion-associated circulatory overload cases were more likely to require mechanical ventilation (71% vs 49%; p < 0.001), experienced longer intensive care and hospital lengths of stay following transfusion, and had higher mortality (21% vs 11%; p = 0.02) even after adjustment for other potentially confounding variables.

CONCLUSIONS

Despite restrictive transfusion practice, transfusion-associated circulatory overload remains a frequent complication of transfusion and is an independent risk factor for in-hospital morbidity and mortality. In addition to cardiovascular and renal risk factors, plasma transfusion was associated with transfusion-associated circulatory overload after controlling for other covariates. Additional research is needed to examine the benefit of reduced erythrocyte or plasma exposure in patients at high risk for transfusion-associated circulatory overload.

Risk factors, management and prevention of transfusion-related acute lung injury: a comprehensive update

Introduction: Despite mitigation strategies that include the exclusion of females from plasma donation or the exclusion of females with a history of pregnancy or known anti-leukocyte antibody, transfusion-related acute lung injury (TRALI) remains a leading cause of transfusion-related morbidity and mortality. Areas covered: The definition of TRALI is discussed and re-aligned with the new Berlin Diagnostic Criteria for the acute respiratory distress syndrome (ARDS). The risk factors associated with TRALI are summarized as are the mitigation strategies to further reduce TRALI. The emerging basic research studies that may translate to clinical therapeutics for the prevention or treatment of TRALI are discussed. Expert opinion: At risk patients, including the genetic factors that may predispose patients to TRALI are summarized and discussed. The re-definition of TRALI employing the Berlin Criteria for ARDS will allow for increased recognition and improved research into pathophysiology and mitigation to reduce this fatal complication of hemotherapy.

A consensus redefinition of transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a serious complication of blood transfusion and is among the leading causes of transfusion-related morbidity and mortality in most developed countries. In the past decade, the pathophysiology of this potentially life-threatening syndrome has been increasingly elucidated, large cohort studies have identified associated patient conditions and transfusion risk factors, and preventive strategies have been successfully implemented. These new insights provide a rationale for updating the 2004 consensus definition of TRALI.

STUDY DESIGN AND METHODS

An international expert panel used the Delphi methodology to develop a redefinition of TRALI by modifying and updating the 2004 definition. Additionally, the panel reviewed issues related to TRALI nomenclature, patient conditions associated with acute respiratory distress syndrome (ARDS) and TRALI, TRALI pathophysiology, and standardization of reporting of TRALI cases.

RESULTS

In the redefinition, the term "possible TRALI" has been dropped. The terminology of TRALI Type I (without an ARDS risk factor) and TRALI Type II (with an ARDS risk factor or with mild existing ARDS) is proposed. Cases with an ARDS risk factor that meet ARDS diagnostic criteria and where respiratory deterioration over the 12 hours before transfusion implicates the risk factor as causative should be classified as ARDS. TRALI remains a clinical diagnosis and does not require detection of cognate white blood cell antibodies.

CONCLUSIONS

Clinicians should report all cases of posttransfusion pulmonary edema to the transfusion service so that further investigation can allow for classification of such cases as TRALI (Type I or Type II), ARDS, transfusion-associated circulatory overload (TACO), or TRALI or TACO cannot distinguish or an alternate diagnosis.

Transfusion-associated circulatory overload and transfusion-related acute lung injury

Transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI) are syndromes of acute respiratory distress that occur within 6 hours of blood transfusion. TACO and TRALI are the leading causes of transfusion-related fatalities, and specific therapies are unavailable. Diagnostically, it remains very challenging to distinguish TACO and TRALI from underlying causes of lung injury and/or fluid overload as well as from each other. TACO is characterized by pulmonary hydrostatic (cardiogenic) edema, whereas TRALI presents as pulmonary permeability edema (noncardiogenic). The pathophysiology of both syndromes is complex and incompletely understood. A 2-hit model is generally assumed to underlie TACO and TRALI disease pathology, where the first hit represents the clinical condition of the patient and the second hit is conveyed by the transfusion product. In TACO, cardiac or renal impairment and positive fluid balance appear first hits, whereas suboptimal fluid management or other components in the transfused product may enable the second hit. Remarkably, other factors beyond volume play a role in TACO. In TRALI, the first hit can, for example, be represented by inflammation, whereas the second hit is assumed to be caused by antileukocyte antibodies or biological response modifiers (eg, lipids). In this review, we provide an up-to-date overview of TACO and TRALI regarding clinical definitions, diagnostic strategies, pathophysiological mechanisms, and potential therapies. More research is required to better understand TACO and TRALI pathophysiology, and more biomarker studies are warranted. Collectively, this may result in improved diagnostics and development of therapeutic approaches for these life-threatening transfusion reactions.

Red blood cell storage lesion: causes and potential clinical consequences

Red blood cells (RBCs) are a specialised organ that enabled the evolution of multicellular organisms by supplying a sufficient quantity of oxygen to cells that cannot obtain oxygen directly from ambient air via diffusion, thereby fueling oxidative phosphorylation for highly efficient energy production. RBCs have evolved to optimally serve this purpose by packing high concentrations of haemoglobin in their cytosol and shedding nuclei and other organelles. During their circulatory lifetimes in humans of approximately 120 days, RBCs are poised to transport oxygen by metabolic/redox enzymes until they accumulate damage and are promptly removed by the reticuloendothelial system. These elaborate evolutionary adaptions, however, are no longer effective when RBCs are removed from the circulation and stored hypothermically in blood banks, where they develop storage-induced damages ("storage lesions") that accumulate over the shelf life of stored RBCs. This review attempts to provide a comprehensive view of the literature on the subject of RBC storage lesions and their purported clinical consequences by incorporating the recent exponential growth in available data obtained from "omics" technologies in addition to that published in more traditional literature. To summarise this vast amount of information, the subject is organised in figures with four panels: i) root causes; ii) RBC storage lesions; iii) physiological effects; and iv) reported outcomes. The driving forces for the development of the storage lesions can be roughly classified into two root causes: i) metabolite accumulation/depletion, the target of various interventions (additive solutions) developed since the inception of blood banking; and ii) oxidative damages, which have been reported for decades but not addressed systemically until recently. Downstream physiological consequences of these storage lesions, derived mainly by in vitro studies, are described, and further potential links to clinical consequences are discussed. Interventions to postpone the onset and mitigate the extent of the storage lesion development are briefly reviewed. In addition, we briefly discuss the results from recent randomised controlled trials on the age of stored blood and clinical outcomes of transfusion.

TACO and TRALI: biology, risk factors, and prevention strategies

Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are the leading causes of transfusion-related morbidity and mortality. These adverse events are characterized by acute pulmonary edema within 6 hours of a blood transfusion and have historically been difficult to study due to underrecognition and nonspecific diagnostic criteria. However, in the past decade, in vivo models and clinical studies utilizing active surveillance have advanced our understanding of their epidemiology and pathogenesis. With the adoption of mitigation strategies and patient blood management, the incidence of TRALI and TACO has decreased. Continued research to prevent and treat these severe cardiopulmonary events is focused on both the blood component and the transfusion recipient.

Transfusion-related acute lung injury risk mitigation: an update

Transfusion-related acute lung injury (TRALI) is a life-threatening complication of transfusion. Greater understanding of the pathophysiology of this syndrome has much improved during the last two decades. Plasma-containing components from female donors with leucocyte antibodies were responsible for the majority of TRALI fatalities before mitigation strategies were implemented. Over the past 15 years, measures to mitigate risk for TRALI have been implemented worldwide and they continued to evolve with time. The AABB requires that all plasma containing components and whole blood for transfusion must be collected from men, women who have not been pregnant, or women who have tested negative for human leucocyte antigen antibodies. Although the incidence of TRALI has decreased following the institution of TRALI mitigation strategies, TRALI is still the most common cause of transfusion-associated death in the United States. In this review, we focus on TRALI risk mitigation strategies. We describe the measures taken by blood collection facilities to reduce the risk of TRALI in the United States, Canada and European countries. We also review the literature for the effectiveness of these measures.

Fifty Years of Research in ARDS. The Epidemiology of Acute Respiratory Distress Syndrome. A 50th Birthday Review

Since its first description 50 years ago, no other intensive care syndrome has been as extensively studied as acute respiratory distress syndrome (ARDS). Despite this extensive body of research, many basic epidemiologic questions remain unsolved. The lack of gold standard tests jeopardizes accurate diagnosis and translational research. Wide variation in the population incidence has been reported, making even simple estimates of the burden of disease problematic. Despite these limitations, there has been an increase in the understanding of pathophysiology and important risk factors both for the development of ARDS and for important patient-centered outcomes like mortality. In this Critical Care Perspective, we discuss the historical context of ARDS description and attempts at its definition. We highlight the epidemiologic challenges of studying ARDS, as well as other intensive care syndromes, and propose solutions to address them. We update the current knowledge of ARDS trends in incidence and mortality, risk factors, and recently described endotypes.

The Risks Associated with Red Blood Cell Transfusion: Implications for Critical Care Practice

This systematic literature review informs the clinician caring for the critically ill patient of the risks associated with red blood cell (RBC) transfusion. Data were extracted from publications between 2008 and 2016 and were reviewed to determine their usefulness in providing evidence associated with the risk of receiving an RBC transfusion. They reveal that this intervention may exacerbate certain clinical conditions and increase mortality and morbidity rates. Further scientific study is needed to better inform clinical practitioners about the inherent risks and benefits associated with the common clinical intervention of RBC transfusion in the critically ill patient.

Acid sphingomyelinase mediates murine acute lung injury following transfusion of aged platelets

Pulmonary complications from stored blood products are the leading cause of mortality related to transfusion. Transfusion-related acute lung injury is mediated by antibodies or bioactive mediators, yet underlying mechanisms are incompletely understood. Sphingolipids such as ceramide regulate lung injury, and their composition changes as a function of time in stored blood. Here, we tested the hypothesis that aged platelets may induce lung injury via a sphingolipid-mediated mechanism. To assess this hypothesis, a two-hit mouse model was devised. Recipient mice were treated with 2 mg/kg intraperitoneal lipopolysaccharide (priming) 2 h before transfusion of 10 ml/kg stored (1–5 days) platelets treated with or without addition of acid sphingomyelinase inhibitor ARC39 or platelets from acid sphingomyelinase-deficient mice, which both reduce ceramide formation. Transfused mice were examined for signs of pulmonary neutrophil accumulation, endothelial barrier dysfunction, and histological evidence of lung injury. Sphingolipid profiles in stored platelets were analyzed by mass spectrophotometry. Transfusion of aged platelets into primed mice induced characteristic features of lung injury, which increased in severity as a function of storage time. Ceramide accumulated in platelets during storage, but this was attenuated by ARC39 or in acid sphingomyelinase-deficient platelets. Compared with wild-type platelets, transfusion of ARC39-treated or acid sphingomyelinase-deficient aged platelets alleviated lung injury. Aged platelets elicit lung injury in primed recipient mice, which can be alleviated by pharmacological inhibition or genetic deletion of acid sphingomyelinase. Interventions targeting sphingolipid formation represent a promising strategy to increase the safety and longevity of stored blood products.

Rare antibody-associated hemolytic transfusion reaction and transfusion-related acute lung injury: a case report

BACKGROUND

Hemolytic transfusion reactions and transfusion-related acute lung injury (TRALI) are life-threatening complications associated with the transfusion of blood products. Hemorrhage is one of the most common surgical complications and the risk of bleeding is particularly acute in patients with hematologic deficiencies. Management of surgical bleeding can be divided into two phases. The first phase centers on immediate control of acute bleeding and the second phase focuses on keeping the patient stable and on reducing the sequelae associated with blood transfusions and blood loss.

CASE PRESENTATION

We present the case of a 53-year-old woman with long-standing immune thrombocytopenia who underwent repair of a symptomatic ventral hernia. On post-operative day one the patient developed hemoperitoneum, requiring exploratory laparotomy and massive transfusion of blood products. The patient's recovery was complicated by consistently low hemoglobin, hematocrit and platelets, prompting frequent transfusion of additional blood products. Shortly after activation of the massive transfusion protocol, the patient developed TRALI. Compounding the situation, on post-operative day sixteen the patient's serum started to show hemolysis: lactate dehydrogenase (LDH) levels rose to 1,845 IU/L, with haptoglobin at less than 5.8 mg/dL and with a high reticulocyte count (4.38%). Previous testing had shown that the patient was positive for most major antigens implicated in antibody formation and was only producing anti-E and anti-K antibodies (considered for all transfusions). Initial pre- and post-transfusion direct antiglobulin tests (DAT) were indeed negative. However, repeat DATs in the days following the noted serum changes were consistent with new allo-antibody formation. These findings prompted immediate withholding of all blood products and a thorough blood bank work up. Despite strong evidence for new allo-antibody formation, no specific known antibody could be identified. The patient recover well when blood products were withheld.

DISCUSSION

We present the case of a 53-year-old woman with long-standing immune thrombocytopenia who underwent repair of a symptomatic ventral hernia. On post-operative day one the patient developed hemoperitoneum, requiring exploratory laparotomy and massive transfusion of blood products. The patient's recovery was complicated by consistently low hemoglobin, hematocrit and platelets, prompting frequent transfusion of additional blood products. Shortly after activation of the massive transfusion protocol, the patient developed TRALI. Compounding the situation, on post-operative day sixteen the patient's serum started to show hemolysis: lactate dehydrogenase (LDH) levels rose to 1,845 IU/L, with haptoglobin at less than 5.8 mg/dL and with a high reticulocyte count (4.38%). Previous testing had shown that the patient was positive for most major antigens implicated in antibody formation and was only producing anti-E and anti-K antibodies (considered for all transfusions). Initial pre- and post-transfusion direct antiglobulin tests (DAT) were indeed negative. However, repeat DATs in the days following the noted serum changes were consistent with new allo-antibody formation. These findings prompted immediate withholding of all blood products and a thorough blood bank work up. Despite strong evidence for new allo-antibody formation, no specific known antibody could be identified. The patient recover well when blood products were withheld. Suspicion for hemolytic transfusion reactions should be high in patients with prior allo-antibody formation; these may present as acute hemolysis or as a delayed hemolytic transfusion reaction. Withholding blood products from these patients until compatible products have been identified is recommended. Moreover, TRALI is the leading cause of transfusion-related fatalities and should always be considered in transfusion settings.

CONCLUSIONS

Suspicion for hemolytic transfusion reactions should be high in patients with prior allo-antibody formation; these may present as acute hemolysis or as a delayed hemolytic transfusion reaction. Withholding blood products from these patients until compatible products have been identified is recommended. Moreover, TRALI is the leading cause of transfusion-related fatalities and should always be considered in transfusion settings.

Reporting transfusion-related acute lung injury by clinical and preclinical disciplines

BACKGROUND

Disciplines involved in diagnosing transfusion-related acute lung injury (TRALI) report according to a "one-hit" theory. However, studies showed that patients with an underlying condition are at increased risk of the development of TRALI. We investigated whether accumulating evidence on the "two-hit" theory has changed the practice of reporting TRALI.

MATERIALS AND METHODS

Departments of haematology, haemovigilance, transfusion medicine, intensive care and anaesthesiology from all Dutch hospitals with at least five beds equipped for mechanical ventilation were invited to participate in an online survey. Using clinical vignettes with conjoint analysis we investigated the effect of patients' age, admission diagnosis, type and number of transfusions and presence of risk factors for acute lung injury on TRALI reporting. A positive β-coefficient indicated a higher likelihood of reporting TRALI.

RESULTS

We received 129 questionnaires (response rate 74%). Respondents were more likely to report TRALI in younger patients, if symptoms developed within 2 hours of transfusion and if patients had received multiple transfusions. Sepsis and the presence of a risk factor for acute lung injury reduced the inclination to report. Transfusion medicine physicians and haemovigilance staff no longer took the age of transfusion products into account in their diagnostic considerations on TRALI.

DISCUSSION

We conclude that the multidisciplinary team involved in TRALI reporting, still considers TRALI a "one-hit" event, despite accumulating evidence that supports the "two-hit" theory. These results suggest that the patients most at risk of developing TRALI are not reported to the blood bank.

Incidence and clinical characteristics of transfusion-associated circulatory overload using an active surveillance algorithm

BACKGROUND

The concordance of haemovigilance criteria developed for surveillance of transfusion-associated circulatory overload (TACO) with its clinical diagnosis has not been assessed. In a pilot study to evaluate an electronic screening algorithm, we sought to examine TACO incidence and application of haemovigilance criteria in patients with post-transfusion pulmonary oedema.

STUDY DESIGN AND METHODS

From June to September 2014, all transfused adult inpatients at four academic hospitals were screened with an algorithm identifying chest radiographs ordered within 12 h of blood component release. Patients with post-transfusion pulmonary oedema underwent case adjudication by an expert panel. TACO incidence was calculated, and clinical characteristics were compared with other causes of post-transfusion pulmonary oedema.

RESULTS

Among 4932 transfused patients, there were 3412 algorithm alerts, 50 cases of TACO and 47 other causes of pulmonary oedema. TACO incidence was 1 case per 100 patients transfused. TACO classification based on two sets of haemovigilance criteria (National Healthcare Safety Network and proposed revised International Society for Blood Transfusion) was concordant with expert panel diagnosis in 57% and 54% of reviewed cases, respectively. Although the majority of clinical parameters did not differentiate expert panel adjudicated TACO from other cases, improved oxygenation within 24 h of transfusion did (P = 0·01).

CONCLUSIONS

The incidence of TACO was similar to that observed in prior studies utilizing active surveillance. Case classification by haemovigilance criteria was frequently discordant with clinical diagnoses of TACO in patients with post-transfusion pulmonary oedema. Improvements in oxygenation within 24 h of transfusion merit further evaluation in the diagnosis of TACO.

Ideal hemoglobin transfusion target for resuscitation of massive-transfusion patients

BACKGROUND

Overtransfusion of packed red blood cells is known to increase the risk of death in stable patients. With the delineation of minimum transfusion ratios in hemorrhaging patients complete, attention must be turned to the other end of the massive transfusion spectrum-that of defining the maximum transfusion of packed red blood cells. We aimed to define the ideal hemoglobin range 24 hours after anatomic hemostasis associated with the lowest mortality.

METHODS

Massive-transfusion patients (≥10 units packed red blood cells within 24 hours) were reviewed from 2010-2013. The hemoglobin 24 ± 6 hours after anatomic hemostasis was used to stratify patients into undertransfusion (<8.0 g/dL), hemoglobin transfusion target (8.0-11.9 g/dL), and overtransfusion (>12.0 g/dL) groups; patients not surviving to 24 hours were excluded.

RESULTS

We identified 418 patients (351 [84%] in the hemoglobin transfusion target group, 38 [9%] in the undertransfusion group, and 29 [7%] in the overtransfusion group) with an overall mortality of 18%. Undertransfusion patients had the greatest risk of death (odds ratio 3.3; 95% confidence interval 1.6-6.7) followed by overtransfusion patients (odds ratio 2.5; 95% confidence interval 1.1-5.6). Though pretransfusion hemoglobin was similar (9.5 ± 2.2 g/dL vs 9.5 ± 2.3 g/dL), overtransfusion patients had greater hemoglobin values during massive transfusion (8.3 ± 3.0 g/dL vs 6.9 ± 1.4 g/dL), persisting until hospital dismissal/death (11.4 ± 2.3 g/dL vs 9.6 ± 1.1 g/dL). In total, 657.4 excess packed red blood cell units were transfused (1.9 ± 1.5 per patient).

CONCLUSION

Overtransfusion patients had increased mortality, comparable to undertransfusion patients, despite younger age and fewer comorbidities. Shorter massive transfusion durations foster a scenario in which patients are at greater risk of overtransfusion.

Recent Advances in Preventing Adverse Reactions to Transfusion

The spectrum of adverse reactions to blood product transfusion ranges from a benign clinical course to serious morbidity and mortality.  There have been many advances in technologies and transfusion strategies to decrease the risk of adverse reactions. Our aim is to address a few of the advancements in increasing the safety of the blood supply, specifically pathogen reduction technologies, bacterial contamination risk reduction, and transfusion associated acute lung injury risk mitigation strategies.

C-reactive protein enhances murine antibody-mediated transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a syndrome of respiratory distress triggered by blood transfusions and is the leading cause of transfusion-related mortality. TRALI has primarily been attributed to passive infusion of HLA and/or human neutrophil antigen antibodies present in transfused blood products, and predisposing factors such as inflammation are known to be important for TRALI initiation. Because the acute-phase protein C-reactive protein (CRP) is highly upregulated during infections and inflammation and can also enhance antibody-mediated responses such as in vitro phagocytosis, respiratory burst, and in vivo thrombocytopenia, we investigated whether CRP affects murine antibody-mediated TRALI induced by the anti-major histocompatibility complex antibody 34-1-2s. We found that BALB/c mice injected with 34-1-2s or CRP alone were resistant to TRALI, however mice injected with 34-1-2s together with CRP had significantly enhanced lung damage and pulmonary edema. Mechanistically, 34-1-2s injection with CRP resulted in a significant synergistic increase in plasma levels of the neutrophil chemoattractant macrophage inflammatory protein-2 (MIP-2) and pulmonary neutrophil accumulation. Importantly, murine MIP-2 is the functional homolog of human interleukin-8, a known risk factor for human TRALI. These results suggest that elevated in vivo CRP levels, like those observed during infections, may significantly predispose recipients to antibody-mediated TRALI reactions and support the notion that modulating CRP levels is an effective therapeutic strategy to reduce TRALI severity.