Transfusion-related immunomodulation (TRIM): an update

Transfusion-associated microchimerism: the hybrid within

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

Update in critical care for the nephrologist: transfusion in nonhemorrhaging critically ill patients

A growing number of guidelines and recommendations advocate a restrictive transfusion strategy. Strong evidence exists that a hemoglobin threshold of less than 7 g/dL conserves resources and may improve outcomes in critically ill patients and that platelet counts greater than 10,000/μL are well tolerated. Patients with coronary artery disease can be safely managed with a restrictive transfusion strategy, utilizing a hemoglobin threshold of less than 7 or 8 g/dL; a threshold of less than 8 g/dL can be applied to patients with acute coronary syndromes. In the absence of coagulopathy with bleeding or high risk for bleeding, plasma transfusion should be withheld. Complications from transfusion are significant and previously under-recognized immunologic complications pose a more serious threat than infections. Erythropoietin and iron administration do not reduce transfusion needs in the critically ill. Interventions to reduce blood loss and educate clinicians are successful in reducing transfusion requirements.

Identifying risk factors for allogenic blood transfusion in oral and oropharyngeal cancer surgery with free flap reconstruction

PURPOSE

Several observational studies in head and neck cancer have reported that allogenic blood transfusion is associated with increased postoperative complications, increased risk of tumor recurrence, and worse prognosis. The aim of this study was to identify preoperative and intraoperative factors predicting blood transfusion in patients undergoing surgery for oral and oropharyngeal cancer.

PATIENTS AND METHODS

We conducted a retrospective cohort study of patients undergoing tumor resection and free flap reconstruction for locally advanced oral and oropharyngeal squamous cell carcinoma between 2000 and 2008. The primary outcome variable was perioperative exposure to allogenic blood transfusion. Univariate and multivariate logistic regression models were used to determine predictors of blood transfusion.

RESULTS

A cohort of 142 participants was found eligible. In a multivariate model, Charlson score ≥ 1 (OR, 5.2; 95% CI, 1.4 to 19.3; P = .01), preoperative hemoglobin levels ≤ 12 g/dl (OR, 4.4; 95% CI, 1.2 to 16.2; P = .03), bone resection (OR, 5.1; 95% CI, 1.5 to 17.8; P = .01), and osseous free tissue transfer (OR, 8.8; 95% CI, 1.0 to 74.8; P = .046) were independently associated with an increased risk of blood transfusion.

CONCLUSION

Our study identified patient- and surgery-related factors predicting a higher risk of exposure to allogenic blood transfusion. This readily available preoperative information could be used to better stratify patients according to their transfusion risk and may thereby guide blood conservation strategies in high-risk patients.

Blood transfusions with high levels of contaminating soluble HLA-I correlate with levels of soluble CD8 in recipients' plasma; a new control factor in soluble HLA-I-mediated transfusion-modulated immunomodulation?

BACKGROUND

The cause of transfusion-related immunomodulation (TRIM) has proved tantalisingly elusive. An ever-growing body of evidence indicates that the infusion of large amounts of soluble and cell-associated antigens into a recipient can somehow induce TRIM. One soluble molecule that has been implicated in TRIM is soluble human leucocyte antigen I (sHLA-I). However, patients infused with large amounts of sHLA-I do not always and unambiguously experience TRIM. As soluble CD8 (sCD8) molecules have been shown to capable of binding membrane and soluble HLA-I molecules, we focused on sCD8 as a possible modulator of sHLA-I-mediated TRIM.

MATERIAL AND METHODS

To this aim we compared the up-regulation of circulating sCD8 in plasma from patients suffering from the same pathology, but chronically transfused with two different blood derivatives: pre- and post-storage leucodepleted red blood cells which contain low and high levels of contaminating sHLA-I, respectively.

RESULTS

Significantly larger amounts of sCD8 circulating molecules were detectable in the plasma of patients transfused with post-storage leucodepleted red blood cells whose supernatants contained significantly larger amounts of sHLA-I contaminating molecules.

CONCLUSION

With the limitation of indirect evidence, this report introduces a new facet of the bioactivity of sCD8 as a possible modulator of sHLA-I-mediated TRIM.

Durable immune response to inactivated H1N1 vaccine is less likely in children with sickle cell anemia receiving chronic transfusions

BACKGROUND

Defects in the immune system may affect vaccine responsiveness. Because of the splenic hypofunction and abnormal opsonic activity, it was unknown whether patients with sickle cell disease (SCD) would respond appropriately to H1N1 vaccination. The objective of this study was to assess seroprotective post-vaccine H1N1 antibody response in children with SCD.

PROCEDURE

Serum antibody titers were measured by hemagglutination inhibition and microneutralization (MN) assays. Correlations were established between clinical and treatment parameters and immune response.

RESULTS

Twenty-nine of 38 (76.3%) subjects (mean age 11 ± 5.4 years) had durable protective antibody titers 8 ± 1.6 months (range 5-12 months) post-vaccination. Lessened immune response was not associated with time interval from vaccination, splenectomy, or hydroxyurea treatment. Lack of antibody response was associated with age less than 3 years and treatment with chronic transfusions. Of the nine non-responders, seven were on chronic transfusions (39% unresponsiveness rate in the transfused group). The difference in the number of patients with seropositivity between the non-transfused and the transfused groups was statistically significant (P = 0.039).

CONCLUSIONS

Most subjects were able to mount an influenza-specific antibody response against the inactivated H1N1 vaccine. Similar to the general population, children less than 3 years were less likely to respond. In addition, patients on chronic transfusions were less likely to respond when compared to non-transfused children. Clinicians should be aware of the possibility of decreased vaccine response in patients with SCD on chronic transfusions. We postulate that transfusion-related immunomodulation (TRIM) may be related to decreased response.

Contemporary perioperative care strategies

Background

Historically, the preoperative and postoperative care of patients with gastrointestinal cancer was provided by surgeons. Contemporary perioperative care is a truly multidisciplinary endeavour with implications for cancer-specific outcomes.

Methods

A literature review was performed querying PubMed and the Cochrane Library for articles published between 1966 to 2012 on specific perioperative interventions with the potential to improve the outcomes of surgical oncology patients. Keywords used were: fast-track, enhanced recovery, accelerated rehabilitation, multimodal and perioperative care. Specific interventions included normothermia, hyperoxygenation, surgical-site infection, skin preparation, transfusion, non-steroidal anti-inflammatory drugs, thromboembolism and antibiotic prophylaxis, laparoscopy, radiotherapy, perioperative steroids and monoclonal antibodies. Included articles had to be randomized controlled trials, prospective or nationwide series, or systematic reviews/meta-analyses, published in English, French or German.

Results

Important elements of modern perioperative care that improve recovery of patients and outcomes in surgical oncology include accelerated recovery pathways, thromboembolism and antibiotic prophylaxis, hyperoxygenation, maintenance of normothermia, avoidance of blood transfusion and cautious use of non-steroidal anti-inflammatory drugs, promotion of laparoscopic surgery, chlorhexidine–alcohol skin preparation and multidisciplinary meetings to determine multimodal therapy.

Conclusion

Multidisciplinary management of perioperative patient care has improved outcomes.

Transfusion issues in cancer patients

Allogeneic blood transfusion (ABT) therapy plays a major role in the case of patients with cancer. Packed red blood cells (PRBC) are given for increased oxygen-carrying capacity, platelets concentrates (PC) and fresh frozen plasma (FFP) for the cessation and prevention of bleeding due to thrombocytopenia and other defects of hemostasis associated with neoplasia. All these blood components can induce complications and/or adverse reactions in cancer patients including transfusion-associated graft versus host disease (TA-GVHD), transfusion transmitted diseases, alloimmunization to blood cell antigens, pulmonary decompensation, immunomodulation. Therefore, specific modifications such as leukocyte-reduction and irradiation of the blood components to be transfused in cancer patients should be introduced to reduce the risk of these complications. Patients undergoing hematopoietic progenitor cell (HPC) transplantation are a unique group and present complex concerns related to transfusion, including major and minor ABO incompatibility and chimeric blood cells. Therefore, transfusion for patients undergoing treatment with cellular therapies requires careful blood component selection. The process of HPC infusion itself carries many risks including DMSO toxicity and hemolytic reactions. In all areas of transfusion therapy, new advances such as pathogen inactivation and synthetic alternatives to blood components should help to increase the safety and tolerance of transfusion in cancer patients.

Insertion/deletion polymorphism of the angiotensin-converting enzyme considerably changes postoperative outcome

STUDY OBJECTIVE

To evaluate the influence of insertion/deletion (ID) polymorphism of the angiotensin-converting enzyme (ACE) gene on clinical outcome of cardiac valve surgery.

DESIGN

Prospective, blinded observational study.

SETTING

Operating room and intensive care unit (ICU) of a university hospital.

PATIENTS

110 adult patients requiring elective cardiac valve surgery requiring cardiopulmonary bypass.

MEASUREMENTS

Patients' preoperative data (age, gender, body weight, New York Heart Association score, medication, biochemical data, and comorbid disorders), anesthetic management (blood pressure, heart rate, blood loss and transfusion, and cardiorespiratory complications and their treatment), and postoperative outcome (life-threatening complications, nosocomial infections, reintubation/reoperation, death, and duration of ICU stay and hospitalization) were recorded. ACE ID was detected by gel electrophoresis following conventional polymerase chain reaction. Patients were divided into two groups postoperatively; groups with II and non-II (ID and DD) genotypes, and group differences were analyzed.

MAIN RESULTS

Distribution of ACE ID in II, ID, and DD genotypes was 29%, 59%, and 12%, respectively. The non-II group had significantly greater postoperative blood loss and transfusion (P < 0.05), more common postoperative infections, and longer ICU stay duration than the II group (P < 0.01).

CONCLUSIONS

ACE ID polymorphism is associated with a higher incidence of postoperative complications, including postoperative infections, in patients undergoing cardiac valve surgery.

Employment of MELD score for the prediction of survival after liver transplantation

OBJECTIVE

To assess the overall accuracy of the preoperative MELD score for predicting survival after liver transplantation (LT) and appraise medium-term (24 months) predictors of survival.

METHODS

We conducted a cross-sectional study including patients transplanted by the Department of General Surgery and Liver Transplantation of the Oswaldo Cruz University Hospital, University of Pernambuco, between July 15th, 2003 and July 14th, 2009. We used analysis of area under ROC (receiver operating characteristic) as a summary measure of the performance of the MELD score and assessed predictors of medium-term survival using univariate and multivariate analysis.

RESULTS

The cumulative survival of three, six, 12 and 24 months of the 208 patients studied was 85.1%, 79.3%, 74.5% and 71.1%, respectively. The preoperative MELD score showed a low discriminatory power for predicting survival after TH. By univariate analysis, we identified intraoperative transfusion of red blood cells (p <0.001) and platelets (p = 0.004) and type of venous hepatocaval anastomosis (p = 0.008) as significantly related to medium-term survival of the patients studied. However, by multivariate analysis only red blood cell transfusion was a significant independent predictor of outcome.

CONCLUSION

The MELD score showed low overall accuracy for predicting post-transplant survival of patients studied, among which only intraoperative transfusion of red blood cells was identified as an independent predictor of survival in the medium term after TH.

Estimating the transfusion risk following total knee arthroplasty

Patients undergoing total knee arthroplasty (TKA) are likely to receive a blood transfusion, which may increase the risk of complications and prolong hospital stay. Considerable variation exists in transfusion practice among orthopedic surgeons following elective TKA. Previous studies have investigated the relationship between preoperative risk factors and the requirement for blood transfusions in patients undergoing a total hip or knee arthroplasty, but few have focused on transfusion risk in those specifically undergoing TKA.The authors performed a retrospective review of a prospectively collected database of 2281 patients undergoing unilateral TKA in a district general hospital over a 10-year period. Multiple regression analysis models were used to identify risk factors associated with postoperative blood transfusion. A predictive model was created based on the regression coefficients and factor levels. The risk of transfusion was independently predicted by the patients' age at surgery (P<.001), preoperative hemoglobin (P<.001), weight (P=.009) and lateral retinacular release (P<.001). The preoperative variables of age, hemoglobin, and weight were incorporated into a model to provide an estimation of the transfusion risk. The area under the receiver operating characteristic curve was 74% (95% confidence interval, 70%-77.5%). This study identifies risk factors independently associated with the risk of requiring a blood transfusion following TKA. The predictive model stratifies the risk according to the individual patient in the preoperative setting, allowing preventative measures to take place preoperatively. It also helps in the counseling of patients at high risk of requiring a postoperative blood transfusion.

Should intraoperative cell-salvaged blood be used in patients with suspected or known malignancy?

PURPOSE

Intraoperative cell salvage (ICS) is used as an alternative to allogeneic blood transfusion in an attempt to avoid or minimize the risks associated with allogeneic blood. Intraoperative cell salvage is generally avoided in surgeries where malignancy is confirmed or suspected due to concern for potential metastasis or cancer recurrence. The application of post-processing methods for ICS is hypothesized to eliminate this potential risk. The purpose of this narrative review is to examine the in vitro experimental evidence as it pertains to the removal of tumour cells from ICS blood and to review the clinical studies where ICS blood has been used in patients with malignancy.

SOURCE

A search of the English literature for relevant articles published from 1973 to 2012 was undertaken using MEDLINE and Cochrane databases. Bibliographies were cross-referenced to locate further studies.

PRINCIPAL FINDINGS

Leukoreduction filters are an effective method for removal of malignant cells from ICS blood. Small non-randomized clinical studies to date do not show evidence of an increased rate of metastasis or cancer recurrence. Although a theoretical risk of disease recurrence persists, the decision to use autologous ICS blood must be weighed against the known risks of allogeneic blood transfusion.

CONCLUSION

Transfusion of autologous blood harvested via ICS should be considered a viable option for reduction or avoidance of allogeneic product during many oncologic surgeries and may be a lifesaving option for those patients who refuse allogeneic blood products.

Critical care considerations in the management of the trauma patient following initial resuscitation

Background

Care of the polytrauma patient does not end in the operating room or resuscitation bay. The patient presenting to the intensive care unit following initial resuscitation and damage control surgery may be far from stable with ongoing hemorrhage, resuscitation needs, and injuries still requiring definitive repair. The intensive care physician must understand the respiratory, cardiovascular, metabolic, and immunologic consequences of trauma resuscitation and massive transfusion in order to evaluate and adjust the ongoing resuscitative needs of the patient and address potential complications. In this review, we address ongoing resuscitation in the intensive care unit along with potential complications in the trauma patient after initial resuscitation. Complications such as abdominal compartment syndrome, transfusion related patterns of acute lung injury and metabolic consequences subsequent to post-trauma resuscitation are presented.

Methods

A non-systematic literature search was conducted using PubMed and the Cochrane Database of Systematic Reviews up to May 2012.

Results and conclusion

Polytrauma patients with severe shock from hemorrhage and massive tissue injury present major challenges for management and resuscitation in the intensive care setting. Many of the current recommendations for “damage control resuscitation” including the use of fixed ratios in the treatment of trauma induced coagulopathy remain controversial. A lack of large, randomized, controlled trials leaves most recommendations at the level of consensus, expert opinion. Ongoing trials and improvements in monitoring and resuscitation technologies will further influence how we manage these complex and challenging patients.

Ubiquitin released in the plasma of whole blood during storage promotes mRNA expression of Th2 cytokines and Th2-inducing transcription factors

Many biological molecules in the stored blood were involved in transfusion-related immunomodulation. One important effect was the differentiation bias of immune cells to Th2 type. In this study, we observed the immune regulation of extracellular ubiquitin accummulated in the plasma of whole blood on the differentiation of T help cells in vitro using ELISA and quantitative fluorescence real-time PCR with the help of LPS stimulated human peripheral blood mononuclear cells. We found extracellular ubiquitin promoted Th2 cytokine IL-4 production and Th2-inducing transcription factor STAT6 expression, but inhibited Th1 cytokine IFN-γ and Th1-inducing transcription factor T-bet, at the same time, proinflammation cytokine TNF-α was also inhibited. These findings probably contribute to the potent evidence that extracellular ubiquitin plays an indispensable role in the differentiation of T help cells which is crucial to the effects of transfusion-related immunomodulation.

Anesthesia in patients with cancer disorders

PURPOSE OF REVIEW

Along with the increasing population of elderly people in developed countries, anesthesiologists have increasing opportunities to anesthetize cancer patients in their routine work. However, no guideline of anesthesia procedures for cancer patients is available even though guidelines of operative procedures have been formulated for different types of cancer. This review provides recent findings related to the optimal choice of anesthetics and adequate anesthesia management for cancer patients.

RECENT FINDINGS

The intrinsic weapon fighting cancer cells is competent immune cells, particularly CD4+ T helper 1-type cells, CD8+ cytotoxic T cells, and natural killer cells. However, surgical inflammation, some anesthetics, and inadvertent anesthesia management suppress these effector cells and induce suppressive immune cells, which render cancer patients susceptible to tumor recurrence and metastasis after surgery.

SUMMARY

Accumulated basic and clinical data suggest that total intravenous anesthesia with propofol, cyclooxygenase antagonists, and regional anesthesia can decrease negative consequences associated with perioperative immunosuppression. Volatile anesthesia, systemic morphine administration, unnecessary blood transfusions, intraoperative hypoxia, hypotension, hypothermia, and hyperglycemia should be avoided.

Can anaesthetic technique effect postoperative outcome?

PURPOSE OF REVIEW

Conventional wisdom maintains that multiple aspects of surgical technique and management may affect postoperative outcome, while anaesthetic technique has little long-term effect on patient outcomes. There is accumulating evidence that, on the contrary, anaesthetic management may in fact exert a number of longer-term effects in postoperative outcome. Here, we review the most topical aspects of anaesthetic management which may potentially influence later postoperative outcomes.

RECENT FINDINGS

There is strong evidence that administration of supplemental oxygen and the avoidance of perioperative hypothermia, allogeneic blood transfusion, hyperglycaemia or large swings in blood glucose levels reduces postoperative infection rates. There is also some evidence that the use of regional anaesthesia techniques reduces chronic postsurgical pain and that avoidance of nitrous oxide reduces the long-term risk of myocardial infarction. Current evidence is equivocal regarding the effects of anaesthesia techniques and cancer recurrence. The instigation of perioperative beta-blockade in noncardiac surgery may not reduce perioperative adverse events or improve postoperative cardiovascular risk.

SUMMARY

Further prospective, large-scale human trials with long-term follow-up are required to clarify the association between anaesthesia and cancer recurrence, neurotoxicity and the developing brain and long-term postoperative cognitive dysfunction in the elderly.

Persistence of elevated plasma CXCL8 concentrations following red blood cell transfusion in a trauma cohort

Red blood cell (RBC) transfusion is associated with alterations in systemic concentrations of IL-8/CXCL8 functional homologs in a murine model. Whether RBC transfusion alters systemic neutrophil chemokine concentrations in individuals sustaining traumatic injury is not known. We conducted a retrospective, single-center study of severely injured trauma patients presenting within 12 h of injury with a base deficit greater than 6 and hypotension in the field. Plasma concentrations of 25 chemokines, cytokines, and growth factors were obtained from both transfused (n = 22) and nontransfused (n = 33) groups in the first 48 h following admission. The transfused group (mean RBC units, 2.7 [SD, 1.7]) tended to be older (49.9 [SD, 21.1] vs. 40.4 [SD, 19.9] years, P = 0.10), with a higher percentage of females (40.9% vs. 18.2%, P = 0.06) and a higher Injury Severity Score (27.1 [SD, 12.7] vs. 21.4 [SD, 10.2], P = 0.07). In univariate and multivariate analyses, transfusion was associated with increased hospital and intensive care unit length of stay but not ventilator-free days. Plasma CXCL8 concentrations were higher in the transfused (84 [SD, 88] pg/mL) than the nontransfused group (31 [SD, 21] pg/mL, P = 0.003). Using a linear prediction model to calculate bioanalyte concentrations standardized for age, sex, Injury Severity Score, and admission SBP, we observed that CXCL8 concentrations diverged within 12 h following injury, with the transfused group showing persistently elevated CXCL8 concentrations by contrast to the decay observed in the nontransfused group. Other bioanalytes showed no differences across time. Red blood cell transfusion is associated with persistently elevated neutrophil chemokine CXCL8 concentrations following traumatic injury.

[Relationship between arginase activity and the storage time of packed red blood cells]

OBJECTIVES

Given the increasing evidence regarding a relationship between packed red blood cells storage time and post-transfusion complications, we decided to determine the relationship between the arginase enzyme levels, biochemical parameters and haemolysis, with the storage time of transfused packed red blood cells.

MATERIAL AND METHODS

We designed a prospective study that included 24 units of packed cells that had been consecutively transfused to patients of our hospital. After recording the storage time of each bag, 15 ml of blood was removed to determine arginase activity, biochemical parameters and haemolysis. A univariate analysis was performed on all the recorded parameters, and included those that were significant in the multiple regression model (P<.05).

RESULTS

The mean storage time was 18.6±6.1 days (range: 6-31 days), with a haematocrit of 59.8%±0.05%, a haemoglobin of 20.3±1.8 g/dl, a pH of 6.5±0.1, and an arginase activity of 140.1±124.0 mU/ml. A linear relationship was observed in the univariate analysis between the storage time and the pH (P=.001), the actual HCO(3) (P=.001), the haemolysis index (P=.035) and the SpO(2) (P=.01). Once adjusted for the confounding variables of the univariate model, a linear relationship was observed between the arginase activity and the storage time (P=.031).

CONCLUSIONS

Our study shows a directly proportional linear relationship between the storage time of packed red blood cells and their arginase activity. We suggest that these findings could be associated with the high incidence of complications after transfusion that may be directly proportional to their storage time.

Non-cancerous prognostic factors of hepatocellular carcinoma after liver transplantation

PURPOSE

To explore non-cancerous factors that may be related with medium-term survival (24 months) after liver transplantation (LT) in this data from northeast Brazil.

METHODS

A cross-sectional study was carried out in patients who underwent deceased-donor orthotopic LT because hepatocellular carcinoma (HCC) at the University of Pernambuco, Brazil. Non-cancerous factors (i.e.: donor-, receptor-, surgery- and center-related variables) were explored as prognostic factors of medium-term survival using univariate and multivariate approachs.

RESULTS

Sixty-one patients were included for analysis. Their three, six, 12 and 24-month overall cumulative survivals were 88.5%, 80.3%, 73.8% and 65.6%, respectively. Our univariate analysis identified red blood cell transfusion (Exp[b]=1.26; p<0.01) and hepato-venous reconstruction technique (84.6% vs. 51.4%, p<0.01; respectively for piggyback and conventional approaches) as significantly related to post-LT survival. The multivariate analysis confirmed the hepato-venous reconstruction technique was an independent prognostic factor.

CONCLUSION

The piggyback technique was related to improved medium-term survival of hepatocellular carcinoma patients after liver transplantation in this northeast Brazilian sample.

Phosphatidylserine-expressing cell by-products in transfusion: A pro-inflammatory or an anti-inflammatory effect?

Labile blood products contain phosphatidylserine-expressing cell dusts, including apoptotic cells and microparticles. These cell by-products are produced during blood product process or storage and derived from the cells of interest that exert a therapeutic effect (red blood cells or platelets). Alternatively, phosphatidylserine-expressing cell dusts may also derived from contaminating cells, such as leukocytes, or may be already present in plasma, such as platelet-derived microparticles. These cell by-products present in labile blood products can be responsible for transfusion-induced immunomodulation leading to either transfusion-related acute lung injury (TRALI) or increased occurrence of post-transfusion infections or cancer relapse. In this review, we report data from the literature and our laboratory dealing with interactions between antigen-presenting cells and phosphatidylserine-expressing cell dusts, including apoptotic leukocytes and blood cell-derived microparticles. Then, we discuss how these phosphatidylserine-expressing cell by-products may influence transfusion.

Absence of transfusion-associated microchimerism in pediatric and adult recipients of leukoreduced and gamma-irradiated blood components

BACKGROUND

Transfusion-associated microchimerism (TA-MC), the persistence of significant levels of donor white blood cells (WBCs) in blood recipients for prolonged periods, has been demonstrated after nonleukoreduced and leukoreduced transfusion to patients with severe traumatic injury. Development of TA-MC has not been rigorously studied in settings that do not involve massive trauma where the blood is leukoreduced and irradiated.

STUDY DESIGN AND METHODS

A cohort of 409 prospectively followed medical and surgical adult and pediatric female recipients of leukoreduced and mostly irradiated allogeneic red blood cell and platelet transfusions were evaluated to determine development of TA-MC. Four- and 8-weeks-posttransfusion samples were analyzed using quantitative real-time polymerase chain reaction for Y-chromosome sequences in WBC DNA, the marker for microchimeric cells in female blood recipients. Repeat testing was performed on Y-chromosome-positive samples to confirm microchimerism (MC), and subsequent posttransfusion samples were tested to investigate persistence of MC.

RESULTS

On initial testing, 40 of 207 (19%) adult and 44 of 202 (22%) pediatric female blood recipients demonstrated low-level MC. On repeat testing of these and additional specimens, 12 (3%) recipients demonstrated low-level transient MC, but none had persistent TA-MC similar to that seen in transfused trauma patients.

CONCLUSION

Persistence of MC was not demonstrated in adult and pediatric recipients of leukoreduced and mostly irradiated blood components. The risk of TA-MC appears to be dependent on the clinical setting and is rare other than in patients sustaining severe traumatic injury.

Outcome of hepatectomy for hepatocellular carcinoma in patients with renal dysfunction

OBJECTIVES

There are few reports on the efficacy of hepatectomy for hepatocellular carcinoma (HCC) in patients with renal dysfunction (RD). This study aimed to clarify the validity of hepatectomy for treating HCC in RD patients, and to compare postoperative courses in RD and non-RD patients.

METHODS

The clinical features of 722 HCC patients who underwent curative hepatectomy between 1986 and 2009 were retrospectively reviewed. Seventeen patients (2.4%) with preoperative serum creatinine levels of >2.0 mg/dl were defined as the RD group, and, of these, seven who did not receive preoperative haemodialysis were defined as borderline patients. Clinicopathological characteristics and postoperative outcomes were compared between the RD group (n= 17) and the non-RD group (n= 705). The postoperative courses of borderline patients were reviewed in detail.

RESULTS

Overall survival (P= 0.177) and disease-free survival (P= 0.942) after hepatectomy did not differ significantly between the groups. Incidences of massive ascites (35.3% vs. 14.3%; P= 0.034) and pleural effusion (52.9% vs. 17.6%; P= 0.001), defined as massive effusion (ME), were significantly higher in the RD group than in the non-RD group. Hypoalbuminaemia (≤2.8 g/dl; P= 0.031), heavy blood loss (≥1000 ml; P= 0.012) and intraoperative blood transfusion (P= 0.007) were risk factors for ME. Among the borderline patients, serum creatinine values were not increased immediately after surgery and four patients underwent haemodialysis.

CONCLUSIONS

Preoperative hypoalbuminaemia, heavy blood loss and blood transfusion are independent risk factors for ME in RD patients. Preoperative improvement of anaemia and reduction of blood loss by meticulous surgical techniques may prevent ME in RD patients who require hepatectomy for HCC.

Transfusion-related mortality after primary hip arthroplasty--an analysis of mechanisms and confounders

BACKGROUND AND OBJECTIVES

Bleeding and postoperative anaemia after total hip arthroplasty (THA) may trigger transfusion of red blood cells (RBC). However, large observational studies have reported associations between RBC transfusion and increased postoperative morbidity and mortality. As major bleeding or severe postoperative anaemia is intrinsically linked with RBC transfusion, direct causality between transfusion and adverse outcomes remains unclear. This study aimed to identify possible relations between RBC transfusion, severe bleeding or anaemia and mortality in all patients who died <90 days after THA in Denmark in 2008.

MATERIALS AND METHODS

Nationwide review of patient records. Cases of adverse transfusion events, infections following transfusion, severe perioperative bleeding or anaemia and possible causal relations to mortality were identified by two independent reviewers.

RESULTS

Of 6932 THA patients, 45 (0·6%) were transfused within 30 days and died <90 days from surgery. Three patients (7%) died from causes possibly related to either severe anaemia, major bleeding alone or major bleeding with transfusion-related acute lung injury, while five (11%) died from infections occurring after RBC transfusion. Mortality in the remaining 37 patients (82%) was of unknown cause (nine patients) or related to patient or surgical factors (28 patients).

CONCLUSION

Transfusion-related mortality after THA included cases of major perioperative bleeding or severe postoperative anaemia with delayed RBC transfusion in addition to possible complications to RBC transfusion per se. Future studies should account for pretransfusion haemoglobin and perioperative blood loss when evaluating RBC transfusion-associated outcomes after surgery.

Sexual dimorphism in hematocrit response following red blood cell transfusion of critically ill surgical patients

The change in hematocrit (ΔHct) following packed red blood cell (pRBCs) transfusion is a clinically relevant measurement of transfusion efficacy that is influenced by post-transfusion hemolysis. Sexual dimorphism has been observed in critical illness and may be related to gender-specific differences in immune response. We investigated the relationship between both donor and recipient gender and ΔHct in an analysis of all pRBCs transfusions in our surgical intensive care unit (2006–2009). The relationship between both donor and recipient gender and ΔHct (% points) was assessed using both univariate and multivariable analysis. A total of 575 units of pRBCs were given to 342 patients; 289 (49.9%) donors were male. By univariate analysis, ΔHct was significantly greater for female as compared to male recipients (3.81% versus 2.82%, resp., P < 0.01). No association was observed between donor gender and ΔHct, which was 3.02% following receipt of female blood versus 3.23% following receipt of male blood (P = 0.21). By multivariable analysis, recipient gender remained associated significantly with ΔHct (P < 0.01). In conclusion, recipient gender is independently associated with ΔHct following pRBCs transfusion. This association does not appear related to either demographic or anthropomorphic factors, raising the possibility of gender-related differences in recipient immune response to transfusion.

Perioperative Red Blood Cell Transfusion: Harmful or Beneficial to the Patient?

Although the transfusion of red blood cells (RBCs) is safer than ever regarding infections, it is still associated with several adverse reactions and therefore should only be used on the basis of evidence-based triggers. However, prevention of RBC transfusion and subsequent substitution of blood losses with acellular solutions will inevitably result in dilutional anemia. Acute dilutional anemia can be compensated by the body over a wide range of hemoglobin concentrations without a critical restriction of tissue oxygenation. On the other hand, chronic anemia is known to be a potent cause of morbidity and mortality. As a consequence, the impact of perioperative anemia on mortality is difficult to describe, because anemia, as well as the transfusion of RBCs, can influence the clinical outcome. The resulting 'Gordian knot' cannot be cut easily, and this circumstance forces clinical physicians to make a daily trade-off between transfusion-associated and anemia-associated risks. This review focuses on the physiology of oxygen transport, the hazards of acute anemia, the hazards of RBC transfusion, and the literature putting these problems into perspective.

Accumulation of pro-cancer cytokines in the plasma fraction of stored packed red cells

INTRODUCTION

Perioperative blood transfusion has been linked to decreased survival in pancreatic cancer; however, the exact causal mechanism has not been elucidated. Allogeneic transfusions are known to expose patients to foreign cells and lipid mediators. We hypothesize that stored packed red cells (pRBCs) contain pro-cancer cytokines that augment tumor progression. We analyzed the plasma fraction of stored pRBCs for pro-cancer cytokines and evaluated the affect of both storage time and leukocyte reduction on these mediators.

METHODS

Chemiarray™ analysis for pro-cancer cytokines was performed on the acellular plasma fraction of stored leukocyte-reduced (LR) and non-leukocyte-reduced (NLR) pRBCs at day 1 (D.1-fresh) and day 42 (D.42-outdate) of storage. Elevated expression of monocyte chemotactic protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), angiogenin, tumor necrosis factor-alpha (TNF-α), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) was found. Specific enzyme-linked immunosorbent assay was performed for each of these factors in LR and NLR blood at D.1, day 28, and D.42. Data were analyzed by ANOVA. A p value ≤ 0.05 was considered significant; N ≥ 4 per group. Migration assays were performed using inhibitors of EGF (gefitinib) and PDGF (imatinib) on murine pancreatic adenocarcinoma cells (Pan02) exposed to D.1 and D.42 LR and NLR plasma. Proliferation assays were performed on Pan02 cells to test the inhibition of PDGF.

RESULTS

MCP-1 levels increased with storage time in LR blood, 86.3 ± 6.3 pg/ml at D.1 vs. 121.2 ± 6.1 pg/ml at D.42 (p = 0.007), and NLR blood, 78.2 ± 7.3 pg/ml at D.1 vs. 647.8 ± 220.7 pg/ml at D.42 (p = 0.02). RANTES levels are lower in LR compared to NLR stored blood, 3.0 ± 1.9 vs. 15.8 ± 0.7 pg/ml at D.42 (p < 0.001), but similar in D.1 blood, 13.8 ± 1.8 pg/ml in LR vs. 12.0 ± 1.6 pg/ml in NLR. Angiogenin levels were different between LR and NLR blood, 0 pg/ml (undetectable) vs. 44.2 ± 3.7 pg/ml (p < 0.001). Storage time did not affect concentration. TNF-α levels were not different between LR and NLR blood, and there was no storage time effect on concentration. EGF and PDGF levels increased with storage time in NLR blood only, 216.4 ± 3.8 pg/ml at D.1 vs. 1,436.4 ± 238.6 pg/ml at D.42 for EGF (p = 0.001), and 61.6 ± 6.0 pg/ml at D.1 vs. 76.5 ± 1.7 pg/ml at D.42 (p = 0.003) for PDGF. Inhibition of EGF reduced migration in Pan02 cells treated with D.42 NLR blood, 245.9 ± 11.2 vs. 164.6 ± 10.6 cells/hpf (p < 0.001). Inhibition of PDGF had no effect on Pan02 migration and reduced cell proliferation in cells treated with D.42 NLR, 181.1 ± 1.5% over control vs. 157.5 ± 2.1% (p < 0.001).

CONCLUSION

Pro-cancer cytokines that can augment tumor progression were identified in pRBCs. Some of these factors are present in fresh blood. The soluble factors identified herein may represent possible therapeutic targets to offset negative effects of transfusion. These data stress the need for efforts in cancer patients to reduce transfusion requirements if needed.

The age of red blood cells is associated with bacterial infections in critically ill trauma patients

BACKGROUND

Blood transfusion increases the risk of nosocomial infection in trauma patients. Specific patient- and transfusion-related risk factors are largely unknown. In this study, risk factors for developing a bacterial infection after transfusion of red blood cells (RBC) or platelets were determined in a cohort of transfused critically ill trauma patients.

MATERIAL AND METHODS

A retrospective study was conducted in a mixed medical-surgical Intensive Care Unit (ICU) of a level-1 university trauma centre, in trauma patients who received a RBC or platelet transfusion. Patients who developed a bacterial infection after transfusion were compared to transfused controls who did not develop such an infection. Multivariable logistic regression was used to determine risk factors for infection.

RESULTS

Of the 7,118 patients admitted to the ICU during the study period, 196 trauma patients met the inclusion criteria. An infection developed in 56 patients (29%). Infection occurred irrespective of the administration of antibiotics as part of selective digestive tract decontamination, surgery status or Injury Severity Score. Transfusion of RBC stored for more than 14 days was associated with infection in trauma patients (odds ratio 1.038, [95% CI: 1.01-1.07], p=0.036). Neither the amount of RBC nor that of platelets was associated with onset of infection.

CONCLUSIONS

Transfusion of RBC stored for more then 14 days is a risk factor for onset of bacterial infection after trauma, irrespective of the use of prophylactic antibiotics. Transfusion of platelets was not a risk factor. These results may contribute to designing prospective studies on transfusion of fresh RBC only in trauma patients.

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

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

Preserved splenic function after angioembolisation of high grade injury

BACKGROUND

After introducing splenic artery embolisation (SAE) in the institutional treatment protocol for splenic injury, we wanted to evaluate the effects of SAE on splenic function and assess the need for immunisation in SAE treated patients.

METHODS

15 SAE patients and 14 splenectomised (SPL) patients were included and 29 healthy blood donors volunteered as controls. Clinical examination, medical history, general blood counts, immunoglobulin quantifications and flowcytometric analysis of lymphocyte phenotypes were performed. Peripheral blood smears from all patients and controls were examined for Howell-Jolly (H-J) bodies. Abdominal doppler, gray scale and contrast enhanced ultrasound (CEUS) were performed on all the SAE patients.

RESULTS

Leukocyte and platelet counts were elevated in both SAE and SPL individuals compared to controls. The proportion of memory B-lymphocytes did not differ significantly from controls in either group. In the SAE group total IgA, IgM and IgG levels as well as pneumococcal serotype specific IgG and IgM antibody levels did not differ from the control group. In the SPL group total IgA and IgG Pneumovax(®) (PPV23) antibody levels were significantly increased, and 5 of 12 pneumococcal serotype specific IgGs and IgMs were significantly elevated. H-J bodies were only detected in the SPL group. CEUS confirmed normal sized and well perfused spleens in all SAE patients.

CONCLUSION

In our study non-operative management (NOM) of high grade splenic injuries including SAE, was followed by an increase in total leukocyte and platelet counts. Normal levels of immunoglobulins and memory B cells, absence of H-J bodies and preserved splenic size and intraparenchymal blood flow suggest that SAE has only minor impact on splenic function and that immunisation probably is unnecessary.

Goal-directed therapy in small animal critical illness

Monitoring critically ill patients can be a daunting task even for experienced clinicians. Goal-directed therapy is a technique involving intensive monitoring and aggressive management of hemodynamics in patients with high risk of morbidity and mortality. The aim of goal-directed therapy is to ensure adequate tissue oxygenation and survival. This article reviews commonly used diagnostics in critical care medicine and what the information gathered signifies and discusses clinical decision making on the basis of diagnostic test results. One example is early goal-directed therapy for severe sepsis and septic shock. The components and application of goals in early goal-directed therapy are discussed.

Low versus high haemoglobin concentration threshold for blood transfusion for preventing morbidity and mortality in very low birth weight infants

BACKGROUND

Infants of very low birth weight often receive multiple transfusions of red blood cells, usually in response to predetermined haemoglobin or haematocrit thresholds. In the absence of better indices, haemoglobin levels are imperfect but necessary guides to the need for transfusion. Chronic anaemia in premature infants may, if severe, cause apnoea, poor neurodevelopmental outcomes or poor weight gain.On the other hand, red blood cell transfusion may result in transmission of infections, circulatory or iron overload, or dysfunctional oxygen carriage and delivery.

OBJECTIVES

To determine if erythrocyte transfusion administered to maintain low as compared to high haemoglobin thresholds reduces mortality or morbidity in very low birth weight infants enrolled within three days of birth.

SEARCH METHODS

Two review authors independently searched the Cochrane Central Register of Controlled Trials (The Cochrane Library) , MEDLINE,EMBASE, and conference proceedings through June 2010.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) comparing the effects of early versus late, or restrictive versus liberal erythrocyte transfusion regimes in low birth weight infants applied within three days of birth, with mortality or major morbidity as outcomes.

[Association between the use of blood components and the five-year mortality after liver transplant]

BACKGROUND AND OBJECTIVES

Liver transplant (LT) surgery is associated with significant bleeding in 20% of cases, and several authors have demonstrated the risks related to blood components. The objective of the present study was to evaluate the impact of using blood components during hospitalization in five-year survival of patients undergoing LT.

METHODS

One hundred and thirteen patients were evaluated retrospectively. Several variables, including the use of blood components intraoperatively and throughout hospitalization, were categorized and evaluated by univariate analysis using Fisher's test. A level of significance of 5% was adopted. Results with p < 0.2 underwent multivariate analysis using multinomial logistic regression.

RESULTS

Parenchymal diseases, preoperative renal dysfunction, and longer stay in hospital and ICU are associated with greater five-year mortality after LT (p < 0.05). Unlike the intraoperative use of blood components, the accumulated transfusion of packed red blood cell, frozen fresh plasma, and platelets during the entire hospitalization was associated with greater five-year mortality after liver transplantation (p < 0.01).

CONCLUSIONS

This study emphasizes the relationship between the use of blood components during hospitalization and increased mortality in five years after LT.

Disseminated fusariosis and endogenous fungal endophthalmitis in acute lymphoblastic leukemia following platelet transfusion possibly due to transfusion-related immunomodulation

Background

To report a case of disseminated fusariosis with endogenous endophthalmitis in a patient with acute lymphoblastic leukemia. Transfusion-associated immune modulation secondary to platelet transfusion could play an important role in the pathophysiology of this case.

Case Presentation

A 9 year-old male with acute lymphoblastic leukemia complicated by pancytopenia and disseminated Intravascular coagulation was given platelet transfusion. He developed disseminated fusariosis and was referred to the ophthalmology team for right endogenous endophthalmitis. The infection was controlled with aggressive systemic and intravitreal antifungals.

Conclusion

Patients with acute lymphoblastic leukemia are predisposed to endogenous fungal endophthalmitis. Transfusion-associated immune modulation may further increase host susceptibility to such opportunistic infections.

In-hospital prognostic value of hemoglobin levels on admission in patients with acute ST segment elevation myocardial infarction undergoing primary angioplasty

PURPOSE

Anemia is a common comorbidity in patients presenting with ST-elevation myocardial infarction (STEMI). The aim of this study was to investigate the in-hospital prognostic value of admission hemoglobin (Hb) levels in patients with acute STEMI undergoing primary percutaneous coronary intervention (p-PCI).

METHODS

This is a retrospective study of 1,625 patients with STEMI stratified by quartiles of admission Hb concentration (Q1 ≤12.5 g/dl, Q2 12.6-13.8 g/dl, Q3 13.9-15.0 g/dl, Q4 ≥15.1 g/dl). Main outcome measures were in-hospital rates of all cause mortality, re-infarction, target vessel revascularization, stroke, heart failure (HF) and bleeding complications.

RESULTS

The incidences of in-hospital mortality according to quartiles from Q1 to Q4 were 8.6, 3.9, 2.4 and 2.6%, respectively (p < 0.001). The incidences of major hemorrhage and HF were significantly higher in Q1, compared to the other quartiles (7.4, 1.9, 3.1, 2.8%, p < 0.001; 16.3, 8.5, 7.7, 9.8%, p < 0.001, respectively). Multiple logistic-regression analysis showed that low admission Hb level (Q1) is an independent and a potent predictor for in-hospital mortality [unadjusted odds ratio (OR): 3.84, 95% confidence interval (CI): 1.78-7.82; p < 0.001].

CONCLUSION

Lower concentrations of Hb on admission are associated with higher rates of in-hospital mortality, heart failure and major bleeding after p-PCI.

Reducing noninfectious risks of blood transfusion

As screening for transfusion-associated infections has improved, noninfectious complications of transfusion now cause the majority of morbidity and mortality associated with transfusion in the United States. For example, transfusion-related acute lung injury, transfusion-associated circulatory overload, and hemolytic transfusion-reactions are the first, second, and third leading causes of death from transfusion, respectively. These complications and others are reviewed, and several controversial methods for prevention of noninfectious complications of transfusion are discussed, including universal leukoreduction of erythrocyte units, use of male-only plasma, and restriction of erythrocyte storage age.

Red blood cell transfusions are independently associated with intra-hospital mortality in very low birth weight preterm infants

OBJECTIVE

To test the hypothesis that red blood cell (RBC) transfusions in preterm infants are associated with increased intra-hospital mortality.

STUDY DESIGN

Variables associated with death were studied with Cox regression analysis in a prospective cohort of preterm infants with birth weight <1500 g in the Brazilian Network on Neonatal Research. Intra-hospital death and death after 28 days of life were analyzed as dependent variables. Independent variables were infant demographic and clinical characteristics and RBC transfusions.

RESULTS

Of 1077 infants, 574 (53.3%) received at least one RBC transfusion during the hospital stay. The mean number of transfusions per infant was 3.3 ± 3.4, with 2.1 ± 2.1 in the first 28 days of life. Intra-hospital death occurred in 299 neonates (27.8%), and 60 infants (5.6%) died after 28 days of life. After adjusting for confounders, the relative risk of death during hospital stay was 1.49 in infants who received at least one RBC transfusion in the first 28 days of life, compared with infants who did not receive a transfusion. The risk of death after 28 days of life was 1.89 times higher in infants who received more than two RBC transfusions during their hospital stay, compared with infants who received one or two transfusions.

CONCLUSION

Transfusion was associated with increased death, and transfusion guidelines should consider risks and benefits of transfusion.

Is the number of blood products transfused associated with lower survival in children with acute lymphoblastic leukemia?

BACKGROUND

Blood transfusion during acute lymphoblastic leukemia (ALL) of childhood is scarcely documented. Children with ALL are immunosuppressed by both the disease and its therapy. Transfusion may contribute to the course of ALL through its transfusion-related immunomodulation (TRIM) effect.

PROCEDURE

Blood transfusion history and response to therapy for 108 children <16 years of age at the time of ALL diagnosis was documented. Clinical files, electronic records, and blood bank registries were scrutinized. Overall survival (OS) and event-free survival (EFS) in relation to blood product type and number of transfusions was determined. Hazard ratios (HR) for death and relapse were estimated through uni- and multivariate Cox regression analysis.

RESULTS

One hundred eight ALL patients were included. Median age was 6 years (range: 0-15 years). Ninety-seven patients (89.8%) were transfused. Median number of transfused products was seven (range: 0-345). After multivariate analysis, transfusion of >5 packed red blood cells (PRBC) remained a significant predictor for death (P = 0.003) and relapse (P = 0.011). For platelets, maximal significance was observed when >30 platelet concentrates (PC) were transfused (P < 0.001). When both, PRBC and PC were considered, maximal significance for predicting death was observed with transfusion of >30 blood products (P < 0.001).

CONCLUSIONS

The number of blood products transfused to children with ALL appears to be significantly associated with lower survival rates. This may reflect both the severity of the disease and the TRIM effect, which may decrease immune surveillance capacity and the probability of leukemic clone eradication.

The Age of Blood Evaluation (ABLE) randomized controlled trial: study design

Red blood cells (RBCs) are transfused to treat anemia and to maintain oxygen delivery to vital organs during critical illness. Laboratory and observational studies have raised the possibility that prolonged RBC storage may adversely affect clinical outcomes. Compared with RBCs stored less than 1 week, there are no clinical data demonstrating that RBCs stored longer remain as effective at carrying or releasing oxygen, and observational studies have risen to possibility that prolonged RBC storage might result in harm to vulnerable patients requiring blood transfusions. The "Age of Blood Evaluation" (ABLE) study (ISRCTN44878718) is a double-blind, multicenter, parallel randomized controlled clinical trial. It will test the hypothesis that the transfusion of prestorage leukoreduced RBCs stored for 7 days or less (fresh arm) as compared with standard-issue RBCs stored, on average, 15 to 20 days (control arm) will lead to lower 90-day all-cause mortality and reduced morbidity in critically ill adults. We include adults in intensive care units (ICUs) who (1) have had a request for a first RBC unit transfusion during the first 7 days of ICU admission and (2) have an anticipated requirement for ongoing invasive and noninvasive mechanical ventilation exceeding 48 hours. Enrolled patients are randomized at the time of transfusion to receive either standard-issue RBC units or RBCs stored 7 days or less issued by the local hospital transfusion service. The primary outcome is 90-day all-cause mortality. Secondary outcomes include ICU and hospital mortality, organ failure, and serious nosocomial infections. With 2510 patients, we will be able to detect a 5% absolute risk reduction (from 25% to 20%). The ABLE study is currently enrolling patients in 23 university-affiliated and community-hospital ICUs across Canada; sites in France and United Kingdom are expected to start recruitment in 2011. Regardless of the results, ABLE study will have significant implications on the duration of RBC storage. A negative trial will reassure clinicians and blood bankers regarding the effectiveness and safety of standard-issue RBCs. A positive trial will have significant implications with respect to inventory management of RBCs given to critically ill adults with a high risk of mortality and will also prompt research to better understand the RBC storage lesion in the hopes of minimizing its clinical consequences through the development of better storage methods.