Patient blood management in the cardiac surgical setting: An updated overview.

In cardiac surgical patients it is a complex challenge to find the ideal balance between anticoagulation and hemostasis. Preoperative anemia and perioperative higher transfusion rates are related to increased morbidity and mortality. Patient blood management (PBM) is an evidence based patient specific individualized protocol used in the perioperative setting in order to reduce perioperative bleeding and transfusion rates and to improve patient outcomes. The three pillars of PBM in cardiac surgery consist of optimization of preoperative erythropoiesis and hemostasis, minimizing blood loss, and improving patient specific physiological reserves. This narrative review focuses on the challenges with special emphasis on PBM in the preoperative phase and intraoperative transfusion management and hemostasis in cardiac surgery patients. It is a "must" that PBM is a collaborative effort between anesthesiologists, surgeons, perfusionists, intensivists and transfusion laboratory teams. This review represents an up to date overview over "PBM in cardiac surgery patients".

The practice of platelet transfusion prior to central venous catheterization in presence of coagulopathy: a national survey among clinicians.

BACKGROUND: Correction of coagulopathy prior to central venous catheter (CVC) placement is advocated by guidelines, while retrospective studies support restrictive use of transfusion products. STUDY DESIGN AND METHODS: We conducted a mixed vignette and questionnaire web survey to investigate current practice and preferences for CVC placement. Clinical vignettes were used to quantify the tendency to administer platelet concentrate. A positive ß-coefficient is in favour of administering platelet concentrate. RESULTS: Ninety-seven physicians answered the survey questions (36 critical care physicians, 14 haematologists, 20 radiologists and 27 anaesthesiologist). Eighty-six physicians subsequently completed the clinical vignettes (response rate 71%). Preferences in favour of correcting thrombocytopenia prior CVC placement were platelet counts of 10 × 109 /L and 20 × 109 /L (ß = 3·9; ß = 3·2, respectively), the subclavian insertion site (ß = 0·8). An elevated INR (INR = 3; ß = 0·6) and an elevated aPTT (aPTT = 60 s; ß = 0·4) showed a positive trend towards platelet transfusion. Platelet transfusion was less likely in an emergency setting (ß = -0·4). Reported transfusion thresholds for CVC placement varied from <10 × 109 /L to 80 × 109 /L for platelet count, from 1·0 to 10·0 for INR and from 25 s to 150 s for aPTT. Implementation of ultrasound guidance as standard practice was limited. CONCLUSION: Current transfusion practice prior to CVC placement is highly variable. Physicians adjust the decision to correct coagulopathy prior CVC placement based on clinical parameters, insertion site and technique applied.

Non-polar lipids accumulate during storage of transfusion products and do not contribute to the onset of transfusion-related acute lung injury.

BACKGROUND AND OBJECTIVES: The accumulation of non-polar lipids arachidonic acid, 5-hydroxyeicosatetraenoic acid (HETE), 12-HETE and 15-HETE during storage of transfusion products may play a role in the onset of transfusion-related acute lung injury (TRALI), a syndrome of respiratory distress after transfusion. MATERIALS AND METHODS: We investigated non-polar lipid accumulation in red blood cells (RBCs) stored for 42 days, plasma stored for 7 days at either 4 or 20°C and platelet (PLT) transfusion products stored for 7 days. Furthermore, we investigated whether transfusion of RBCs with increased levels of non-polar lipids induces TRALI in a 'two-hit' human volunteer model. All products were produced following Dutch Blood Bank protocols and are according to European standards. Non-polar lipids were measured with high-performance liquid chromotography followed by mass spectrometry. RESULTS: All non-polar lipids increased in RBCs after 21 days of storage compared to baseline. The non-polar lipid concentration in plasma increased significantly, and the increase was even more pronounced in products stored at 20°C. In platelets, baseline levels of 5-HETE and 15-HETE were higher than in RBCs or plasma. However, the non-polar lipids did not change significantly during storage of PLT products. Infusion of RBCs with increased levels of non-polar lipids did not induce TRALI in LPS-primed human volunteers. CONCLUSION: We conclude that non-polar lipids accumulate in RBC and plasma transfusion products and that accumulation is temperature dependent. Accumulation of non-polar lipids does not appear to explain the onset of TRALI (Dutch Trial Register - NTR4455).

Underdiagnosing of antibody-mediated transfusion-related acute lung injury: evaluation of cellular-based versus bead-based techniques.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. To support the diagnosis of antibody-mediated TRALI, HLA and HNA antibodies are tested in involved blood donors. Identification of antibody positive donors is important as exclusion of these donors is part of preventative strategies against TRALI. We compared cellular-based versus bead-based techniques for diagnosis of antibody-mediated TRALI. MATERIALS AND METHODS: All reported TRALI cases in the Netherlands during a 5-year period were evaluated. Donors were screened for the presence of HLA class I and class II antibodies using both cellular-based and bead-based techniques. RESULTS: In total, 100 TRALI cases were reported of which 91 were fully tested. In 113 donors, HLA antibodies were detected of which 84 were only detected by bead-based techniques, 12 only by cellular-based tests and 17 by both assays. Antibody-mediated TRALI was diagnosed in 44 of 91 reported cases. Twenty-one (48%) of these cases would not have been identified using only cellular-based assays. CONCLUSION: Bead-based techniques show a higher sensitivity for detecting incompatible donors in TRALI cases than cellular-based assays. These results suggest that the use of bead-based assays will result in a significant reduction of future TRALI reactions as more antibody positive donors will be excluded from future donations.

25-Hydroxyvitamin D concentrations do not affect the humoral or cellular immune response following SARS-CoV-2 mRNA vaccinations.

BACKGROUND: To improve effectiveness of vaccination against SARS-CoV-2, it is important to identify factors that influence the immune response induced by vaccination. Evidence for the role of vitamin D in immune response against SARS-CoV-2 is contradictory. It is therefore of interest whether 25-hydroxyvitamin D (25[OH]D) concentrations affect the humoral and/or cellular response following SARS-CoV-2 vaccination. METHODS: In this prospective cohort study, blood samples were collected from 98 SARS-CoV-2 naive health care workers (HCW) receiving the first two doses of either BNT162b2 or mRNA-1273 in 2021. Wild-type spike (S) protein binding and neutralizing antibodies were determined approximately three weeks after the first dose and four to five weeks after the second dose. Antigen specific T-cells and functionality (proliferative response and interferon gamma [IFN-γ] release) were determined in 18 participants four weeks after the second dose of BNT162b2. We studied the association between 25(OH)D concentrations, which were determined prior to vaccination, and humoral and cellular immune responses following vaccination. RESULTS: We found no association between 25(OH)D concentrations (median 55.9 nmol/L [IQR 40.5-69.8]) and binding or neutralizing antibody titers after complete vaccination (fold change of antibody titers per 10 nmol/L 25(OH)D increase: 0.98 [95% CI 0.93-1.04] and 1.03 [95% CI: 0.96-1.11], respectively), adjusted for age, sex and type of mRNA vaccine. Subsequently, continuous 25(OH)D concentrations were divided into commonly used clinical categories (<25 nmol/L [n = 6, 6%], 25-49 nmol/L [n = 33, 34%], 50-75 nmol/L [n = 37, 38%] and ≥75 nmol/L [n = 22, 22%]), but no association with the humoral immune response following vaccination was found. Also, 25(OH)D concentrations were not associated with the SARS-CoV-2 specific T cell response. CONCLUSION: No association was found between 25(OH)D concentrations and the humoral or cellular immune response following mRNA vaccination against SARS-CoV-2. Based on our findings there is no rationale to advise vitamin D optimization preceding SARS-CoV-2 vaccination in HCW with moderate vitamin D status.

The effect of immunosuppressive therapies on the endothelial host response in critically ill COVID-19 patients.

While several effective therapies for critically ill patients with COVID-19 have been identified in large, well-conducted trials, the mechanisms underlying these therapies have not been investigated in depth. Our aim is to investigate the association between various immunosuppressive therapies (corticosteroids, tocilizumab and anakinra) and the change in endothelial host response over time in critically ill COVID-19 patients. We conducted a pre-specified multicenter post-hoc analysis in a Dutch cohort of COVID-19 patients admitted to the ICU between March 2020 and September 2021 due to hypoxemic respiratory failure. A panel of 18 immune response biomarkers in the complement, coagulation and endothelial function domains were measured using ELISA or Luminex. Biomarkers were measured on day 0-1, day 2-4 and day 6-8 after start of COVID-19 treatment. Patients were categorized into four treatment groups: no immunomodulatory treatment, corticosteroids, anakinra plus corticosteroids, or tocilizumab plus corticosteroids. The association between treatment group and the change in concentrations of biomarkers was estimated with linear mixed-effects models, using no immunomodulatory treatment as reference group. 109 patients with a median age of 62 years [IQR 54-70] of whom 72% (n = 78) was male, were included in this analysis. Both anakinra plus corticosteroids (n = 22) and tocilizumab plus corticosteroids (n = 38) were associated with an increase in angiopoietin-1 compared to no immune modulator (n = 23) (beta of 0.033 [0.002-0.064] and 0.041 [0.013-0.070] per day, respectively). These treatments, as well as corticosteroids alone (n = 26), were further associated with a decrease in the ratio of angiopoietin-2/angiopoietin-1 (beta of 0.071 [0.034-0.107], 0.060 [0.030-0.091] and 0.043 [0.001-0.085] per day, respectively). Anakinra plus corticosteroids and tocilizumab plus corticosteroids were associated with a decrease in concentrations of complement complex 5b-9 compared to no immunomodulatory treatment (0.038 [0.006-0.071] and 0.023 [0.000-0.047], respectively). Currently established treatments for critically ill COVID-19 patients are associated with a change in biomarkers of the angiopoietin and complement pathways, possibly indicating a role for stability of the endothelium. These results increase the understanding of the mechanisms of interventions and are possibly useful for stratification of patients with other inflammatory conditions which may potentially benefit from these treatments.

Monitoring, management, and outcome of hypotension in Intensive Care Unit patients, an international survey of the European Society of Intensive Care Medicine.

INTRODUCTION: Hypotension in the ICU is common, yet management is challenging and variable. Insight in management by ICU physicians and nurses may improve patient care and guide future hypotension treatment trials and guidelines. METHODS: We conducted an international survey among ICU personnel to provide insight in monitoring, management, and perceived consequences of hypotension. RESULTS: Out of 1464 respondents, 1197 (81.7%) were included (928 physicians (77.5%) and 269 nurses (22.5%)). The majority indicated that hypotension is underdiagnosed (55.4%) and largely preventable (58.8%). Nurses are primarily in charge of monitoring changes in blood pressure, physicians are in charge of hypotension treatment. Balanced crystalloids, dobutamine, norepinephrine, and Trendelenburg position were the most frequently reported fluid, inotrope, vasopressor, and positional maneuver used to treat hypotension. Reported complications believed to be related to hypotension were AKI and myocardial injury. Most ICUs do not have a specific hypotension treatment guideline or protocol (70.6%), but the majority would like to have one in the future (58.1%). CONCLUSIONS: Both physicians and nurses report that hypotension in ICU patients is underdiagnosed, preventable, and believe that hypotension influences morbidity. Hypotension management is generally not protocolized, but the majority of respondents would like to have a specific hypotension management protocol.

Definition and incidence of hypotension in intensive care unit patients, an international survey of the European Society of Intensive Care Medicine.

INTRODUCTION: Although hypotension in ICU patients is associated with adverse outcome, currently used definitions are unknown and no universally accepted definition exists. METHODS: We conducted an international, peer-reviewed survey among ICU physicians and nurses to provide insight in currently used definitions, estimations of incidence, and duration of hypotension. RESULTS: Out of 1394 respondents (1055 physicians (76%) and 339 nurses (24%)), 1207 (82%) completed the questionnaire. In all patient categories, hypotension definitions were predominantly based on an absolute MAP of 65 mmHg, except for the neuro(trauma) category (75 mmHg, p < 0.001), without differences between answers from physicians and nurses. Hypotension incidence was estimated at 55%, and time per day spent in hypotension at 15%, both with nurses reporting higher percentages than physicians (estimated mean difference 5%, p = 0.01; and 4%, p < 0.001). CONCLUSIONS: An absolute MAP threshold of 65 mmHg is most frequently used to define hypotension in ICU patients. In neuro(trauma) patients a higher threshold was reported. The majority of ICU patients are estimated to endure hypotension during their ICU admission for a considerable amount of time, with nurses reporting a higher estimated incidence and time spent in hypotension than physicians.

A survey of physicians' reasons to transfuse plasma and platelets in the critically ill: a prospective single-centre cohort study.

Data on the rationality of transfusion practice of fresh frozen plasma (FFP) and platelets in the critically ill are sparse and may contribute to efforts to reduce transfusion rates. To provide insight into determinants of the decision of intensive care unit (ICU)-physicians to transfuse, a survey study was performed. The reasons of ICU-physicians to transfuse FFP and platelets were determined during a 10-week period. Transfusion triggers were assessed, as well as correction of prolonged coagulation test results. Of 310 admissions, 44 patients (14%) received a transfusion of FFP and 35 patients (11%) received a platelet transfusion. In 67% patients, FFPs were transfused in bleeding patients and in 33% in non-bleeding patients. FFP was transfused at a prothrombin time (PT) of 19 s (17-22). After FFP transfusion, PT levels of 15-18, 18-20 and 20-26 s decreased with a median of 0.7, 1.9 and 3.5 s, respectively. On average, 3.2 FFP units were ordered, of which 28% was not transfused. The major reason to transfuse platelets was bleeding. Platelets were transfused at a platelet count of 95 (36-116) x 10(9) L(-1) in bleeding and 13 (10-18) x 10(9) L(-1) in non-bleeding patients. On average, 1.4 platelet units were ordered, of which 20% was not transfused. The agreement between physicians reporting a major bleeding and a definition of bleeding was poor (kappa < 0.10 for FFP and 0.20 for platelets). In conclusion, one-third of FFP transfusions was given to non-bleeding patients. FFP transfusion failed to normalize prolonged coagulation test results in the majority of the patients. Transfusion of platelets was restrictive in non-bleeding patients and liberal in bleeding patients. Education on indications of FFP transfusion and improved identification of bleeding may reduce transfusion rates.

Diagnosing acute lung injury in the critically ill: a national survey among critical care physicians.

BACKGROUND: Incidence reports on acute lung injury (ALI) vary widely. An insight into the diagnostic preferences of critical care physicians when diagnosing ALI may improve identification of the ALI patient population. METHODS: Critical care physicians in the Netherlands were surveyed using vignettes involving hypothetical patients and a questionnaire. The vignettes varied in seven diagnostic determinants based on the North American European Consensus Conference and the lung injury score. Preferences were analyzed using a mixed-effects logistic regression model and presented as an odds ratio (OR) with a 95% confidence interval. RESULTS: From 243 surveys sent to 30 hospitals, 101 were returned (42%). ORs were as follows: chest X-ray consistent with ALI: OR 1.7 (1.3-2.3), high positive end-expiratory pressure (PEEP) (15 cmH(2)O): OR 5.0 (3.9-6.6), low pulmonary artery occlusion pressures (PAOP) (<18 mmHg): OR 4.7 (3.6-6.1), low compliance (30 ml/cmH(2)O): OR 0.7 (0.5-0.9), low PaO(2)/FiO(2) (<250 mmHg): OR 9.2 (6.9-12.3), absence of heart failure: OR 1.2 (0.9-1.5), presence of a risk factor for ALI (sepsis): OR 1.0 (0.8-1.3). The questionnaire revealed that critical care physicians with an anesthesiology background differed from physicians with an internal medicine background with regard to hemodynamic variables when considering an ALI diagnosis (P<0.05). CONCLUSIONS: Dutch critical care physicians consider the PEEP level, but not the presence of a risk factor for ALI, as an important factor to diagnose ALI. Background specialty of critical care physicians influences diagnostic preferences and may account for variance in the reported incidence of ALI.

Donor characteristics do not influence transfusion-related acute lung injury incidence in a secondary analysis of two case-control studies.

OBJECTIVE: To investigate the relation between donor characteristics and TRALI incidence. BACKGROUND: Transfusion-related acute lung injury (TRALI) is a potentially fatal complication of transfusion. In pre-clinical studies and several clinical studies, TRALI has been related to loss of product quality during red blood cell (RBC) storage, called the "storage lesion". Donor characteristics, as for example age, genetics and life style choices influence this "storage lesion". We hypothesized that donor sex, age and blood type is related to TRALI incidence. METHODS/MATERIALS: We performed a secondary analysis of two cohort studies, designed to identify TRALI risk factors by matching TRALI patients to transfused controls. We obtained donor sex, age and blood type from the Dutch Blood Bank Sanquin and investigated TRALI incidence in patients who were exposed to a certain donor characteristic. We used Kruskal-Wallis testing to compare the number of transfused products and Chi2 testing to compare proportions of TRALI patients and transfused control. RESULTS: After implementation of the male-donor only plasma strategy, patients received more transfusion products from male donors. However, we did not detect a relation between TRALI incidence and donor sex. Both TRALI patients and transfused controls received mainly products from donors over 41 years old, but donor age did not influence TRALI risk. Donor blood type, the transfusion of blood type-compatible and blood type-matched products also had no influence on TRALI incidence. CONCLUSION: We conclude that in two cohorts of TRALI patients, donor age, donor sex and donor blood type are unrelated to TRALI.

International point prevalence study of Intensive Care Unit transfusion practices-Pilot study in the Netherlands.

BACKGROUND: Anaemia and coagulopathy are common issues in critically ill patients. Transfusion can be lifesaving, however, is associated with potential life threatening adverse events. As an international transfusion guideline for this specific patient population is lacking, we hypothesize that a high heterogeneity in transfusion practices exists. In this pilot-study we assessed transfusion practice in a university hospital in the Netherlands and tested the feasibility of this protocol for an international multi-centre study. METHODS: A prospective single centre cohort study was conducted. For seven days all consecutive non-readmitted patients to the adult Intensive Care Unit (ICU) were included and followed for 28 days. Patients were prospectively followed until ICU discharge or up to day 28. Patient outcome data was collected at day 28. Workload for this study protocol was scored in hours and missing data. RESULTS: In total, 48 patients were included, needed in total three hours patient to include and collect all data, with 1.6% missing data showing the feasibility of the data acquisition. Six (12.5%) patients received red blood cells (RBCs), three patients (6.3%) received platelet concentrates, and two (4.2%) patients received plasma units. In total eight (16.7%) patients were transfused with one or more blood products. Median pre- and post-transfusion haemoglobin (Hb) levels were 7.6 (6.7-7.7) g/dL and 8.1 (7.6-8.7) g/dL, respectively. CONCLUSION: In this pilot-study we proved the feasibility of our protocol and observed in this small population a restrictive transfusion practice for all blood products.

[Transfusion-related acute lung injury (TRALI) in the Netherlands in 2002-2005]. / Transfusiegerelateerde acute longbeschadiging (TRALI) in Nederland in 2002-2005.

OBJECTIVE: To determine the number of reported cases of transfusion-related acute lung injury (TRALI) in the Netherlands in 2002-2005 and to determine how many cases were associated with incompatibility between leukocyte-reactive antibodies in the donor plasma and leukocytes or antigens in the recipient. DESIGN: Retrospective national case review. METHOD: Cases of TRALI reported in 2002-2005 were assessed according to the national clinical definition of TRALI, and the relationship between TRALI and transfusion was assessed. Additional clinical details were requested from the treating hospital as necessary. The results of leukocyte serological tests from donors and recipients were linked to clinical cases. For cases with positive leukocyte serological tests, the relevant blood components and the sex of the donor were recorded. RESULTS: Of the 46 cases reported, 6 had insufficient information. 8 cases did not meet the definition or had another more likely diagnosis. There was a trend toward an increase in the number of reports: 12 cases were reported in 2005, corresponding with 1:60,000 blood components. Of the 40 evaluable cases, 32 (80%) met the definition of TRALI and were deemed to be definitely (n = 16), probably (n = 5) or possibly (n = 11) related to transfusion. Severity ranged from moderate to life-threatening, and there was one TRALI-related death. Leukocyte serology was fully investigated in 18 cases: 13 (72%) had leukocyte incompatibility and in 5 cases exclusively fresh frozen plasma from a female donor was implicated.

The role of endothelium in the onset of antibody-mediated TRALI.

Transfusion Related Acute Lung Injury (TRALI) is one of the leading causes of mortality and morbidity following blood transfusion. The mechanisms behind the disease are not yet fully understood but seem to involve many different activating pathways and donor factors, in synergy with patient susceptibility. Studies have focused mostly on neutrophil activation, as aggregates of neutrophils and edema in lungs are found in post-mortem histological sections. This review aims to highlight the role of the endothelium in TRALI, as activated endothelium is the main promoter of leukocyte transmigration, and creates the barrier between blood and tissue. Since recent evidence suggests that a strong endothelial barrier prevents leukocyte transmigration and vascular leakage, we suggest that strengthening this barrier may be key to TRALI prevention.

Glucarpidase treatment for methotrexate intoxication: a case report and review of the literature.

High-dose methotrexate (MTX) induced acute kidney injury can lead to sustained high systemic MTX levels and severe toxicity. A 39-year-old man with lymphoblastic T-cell lymphoma was admitted to our intensive care unit with elevated serum creatinine and prolonged high serum MTX levels. Standard supportive care was complemented by the addition of a relatively novel agent, glucarpidase, which rapidly lowered the extracellular levels of MTX. Several case series support this effect of glucarpidase, but no randomised controlled trial has been performed to show this leads to better outcome. Furthermore, glucarpidase might negatively affect leucovorin rescue therapy. Lastly, glucarpidase carries a significant financial burden. Based on the current evidence we cannot recommend glucarpidase until further research elucidates its role in the treatment of MTX toxicity. There is no randomised clinical evidence to support its use in severe cases and theoretical evidence suggests that after prolonged exposure to high MTX levels glucarpidase administration is unable to reverse high intracellular MTX. We recommend that new randomised controlled studies be aimed at early administration of glucarpidase in patients with high MTX levels shortly after administration to prevent direct toxic effects of MTX on kidney function and further uptake into cells.

Transfusion-associated circulatory overload: A survey among Dutch intensive care fellows.

OBJECTIVES: Transfusion-associated circulatory overload (TACO) is a severe pulmonary transfusion reaction and leading cause of transfusion-related morbidity and mortality in Europe. TACO is of particular importance in critically ill patients, since they often receive blood transfusions and have multiple risk factors for TACO. This study investigates transfusion practices in patients at risk of developing TACO, and furthermore knowledge concerning risk factors, diagnoses and treatment strategies among Dutch intensive care unit (ICU) fellows. MATERIAL AND METHODS: An unannounced paper-based survey was conducted among Dutch ICU fellows during an educational conference. The survey consisted of 16 multiple and open choice questions. RESULTS: Of all 65 Dutch ICU fellows 56.8% completed the survey; of respondents 88.9% identified the correct constellation of symptoms for TACO. In total, 29.7% of the respondents are aware they are obligated to report TACO cases to the blood bank. Major risk factors for TACO that respondents identified were reduced left ventricular function, infusion volume and infusion rate. In a non-emergency setting, 45.9% of fellows start red blood cell transfusion with 2 units or more. Transfusion rates exceeded national guidelines in 15.4% of fictitious cases. TACO is treated with furosemide by 94.5% of the fellows, however goals of the therapy varied greatly. CONCLUSION: Dutch ICU fellows are knowledgeable of TACO symptoms, risk factors and treatment, however knowledge on reporting and transfusion practice in the setting of at risk patients for TACO should be improved.

[A patient with repeated, life-threatening gastro-intestinal haemorrhages treated by means of medication, open surgery, endoscopic surgery, intervention radiology and conservative methods]. / Een patiënt met recidiverende levensbedreigende darmbloedingen behandeld met medicamenteuze, chirurgische, endoscopische, interventieradiologische en conservatieve methoden.

A 56-year-old man with Henoch Schönlein purpura vasculitis suffered from repeated and multiple life-threatening gastrointestinal haemorrhages. Over recent years a number of interventions for the treatment of gastrointestinal haemorrhaging have become available; choosing which option to use can present difficulties. The available interventions are carried out by different disciplines and include haemostatic drugs, endoscopic intervention, intervention radiology, and surgery. In this patient, following a severe drop in haemoglobin levels, CT and angiography revealed active bleeding in the distal jejunum. Transarterial embolization by means of a coiling procedure halted the bleeding. The patient was also given tranexamic acid, a fibrinolysis inhibitor. More episodes of bleeding subsequently followed which necessitated further coiling procedures, two bowel resections, the endoscopic clipping of a bleeding artery, treatment with the recombinant activated factor VII (rFVIIa) at a dosage of 90 microg/kg, as well as conservative treatment with multiple transfusions of filtered erythrocytes and fresh plasma. The patient eventually recovered.

Transfusion-related acute lung injury: Current understanding and preventive strategies.

Transfusion-related acute lung injury (TRALI) is the most serious complication of transfusion medicine. TRALI is defined as the onset of acute hypoxia within 6 hours of a blood transfusion in the absence of hydrostatic pulmonary oedema. The past decades have resulted in a better understanding of the pathogenesis of this potentially life-threating syndrome. The present notion is that the onset of TRALI follows a threshold model in which both patient and transfusion factors are essential. The transfusion factors can be divided into immune and non-immune mediated TRALI. Immune-mediated TRALI is caused by the passive transfer of human neutrophil antibodies (HNA) or human leukocyte antibodies (HLA) present in the blood product reacting with a matching antigen in the recipient. Non-immune mediated TRALI is caused by the transfusion of stored cell-containing blood products. Although the mechanisms behind immune-mediated TRALI are reasonably well understood, this is not the case for non-immune mediated TRALI. The increased understanding of pathways involved in the onset of immune-mediated TRALI has led to the design of preventive strategies. Preventive strategies are aimed at reducing the risk to exposure of HLA and HNA to the recipient of the transfusion. These strategies include exclusion of "at risk" donors and pooling of high plasma volume products and have shown to reduce the TRALI incidence effectively. This review discusses the current understanding of TRALI and preventive strategies available.