Length of storage and in vitro immunomodulation induced by prestorage leukoreduced red blood cells

The Association Between Perioperative Red Blood Cell Transfusions and 1-Year Mortality After Major Cancer Surgery: An International Multicenter Observational Study

BACKGROUND

Packed red blood cell (pRBC) transfusions in patients undergoing surgery for cancer are given to treat anemia or acute hemorrhage. Evidence indicates that pRBC transfusions are associated with poor perioperative and oncological outcomes. The ARCA-1 (Perioperative Care in the Cancer Patient-1) study was designed to test the association between perioperative pRBC transfusions and postoperative morbidity and mortality in patients undergoing cancer surgery. The primary hypothesis of our study was that perioperative pRBC transfusions have a negative impact on postoperative morbidity and 1-year mortality.

METHODS

ARCA-1 was an international multicenter prospective observational cohort study. Participating centers enrolled a minimum of 30 consecutive adult patients with cancer who underwent surgery with curative intent. The primary end point was all-cause mortality 1 year after major cancer surgery. Secondary end points were rates of perioperative blood product use, 1-year cancer-specific mortality, overall survival, and 30-day morbidity and mortality. We performed a propensity score matching analysis to adjust for selection bias. A multivariable logistic regression model was fitted to estimate the effects of significant covariates on 1-year mortality, cancer-related mortality, and overall survival.

RESULTS

A total of 1079 patients were included in the study. The rate of perioperative pRBC transfusions was 21.1%. Preoperative comorbidities, including anemia, American Society of Anesthesiologists (ASA) score of III to IV, a history of coronavirus disease 2019 (COVID-19), myocardial infarction, stroke, need for dialysis, history of blood transfusions, and metastatic disease were statistically significantly more frequent in transfused patients compared to nontransfused patients. The 1-year mortality rate was higher in transfused patients before (19.7% vs 6.5%; P < .0001) and after (17.4% vs 13.2%; P = .29) propensity score matching. 1-year mortality was 1.97 times higher in transfused than in no-transfused patients (odd ratio [OR], 1.97; 95% confidence interval [CI], 1.13-3.41). The odds of 1-year cancer mortality for patients who had perioperative pRBCs was 1.82 times higher (OR, 1.82; 95% CI, 0.97-3.43) compared to those who did not receive perioperative pRBC transfusion. The effect of perioperative pRBC transfusion on overall survival was also significant (hazard ratio [HR], 1.85; 95% CI, 1.15-2.99). Transfused patients also had a higher rate of 30-day postoperative mortality before (3.5% vs 0.7%; P = .0009) and after propensity score matching (4.2% vs 1.8%; P = .34).

CONCLUSIONS

This international, multicenter observational study showed that perioperative pRBC transfusion was associated with an increased mortality risk.

Study protocol of the WashT Trial: transfusion with washed versus unwashed red blood cells to reduce morbidity and mortality in infants born less than 28 weeks' gestation - a multicentre, blinded, parallel group, randomised controlled trial

INTRODUCTION

Many extremely preterm newborns develop anaemia requiring a transfusion, with most receiving three to five transfusions during their admission. While transfusions save lives, the potential for transfusion-related adverse outcomes is an area of growing concern. Transfusion is an independent predictor of death and is associated with increased morbidity, length of hospital stay, risk of infection and immune modulation. The underlying mechanisms include adverse pro-inflammatory and immunosuppressive responses. Evidence supports an association between transfusion of washed red cells and fewer post-transfusion complications potentially through removal of chemokines, lipids, microaggregates and other biological response modifiers. However, the clinical and cost-effectiveness of washed cells have not been determined.

METHODS AND ANALYSIS

This is a multicentre, randomised, double-blinded trial of washed versus unwashed red cells. Infants <28 weeks' gestation requiring a transfusion will be enrolled. Transfusion approaches will be standardised within each study centre and will occur as soon as possible with a recommended fixed transfusion volume of 15 mL/kg whenever the haemoglobin is equal to or falls below a predefined restrictive threshold, or when clinically indicated. The primary outcome is a composite of mortality and/or major morbidity to first discharge home, defined as one or more of the following: physiologically defined bronchopulmonary dysplasia; unilateral or bilateral retinopathy of prematurity grade >2, and; necrotising enterocolitis stage ≥2. To detect a 10% absolute reduction in the composite outcome from 69% with unwashed red blood cell (RBCs) to 59% with washed RBCs with 90% power, requires a sample size of 1124 infants (562 per group). Analyses will be performed on an intention-to-treat basis with a prespecified statistical analysis plan. A cost-effectiveness analysis will also be undertaken.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Women's and Children's Health Network Human Research Ethics Committee (HREC/12/WCHN/55). The study findings will be disseminated through peer-reviewed articles and conferences.

TRIAL REGISTRATION NUMBER

ACTRN12613000237785 Australian New Zealand Clinical Trials Registry.

Blood Transfusion is Associated With Adverse Outcomes in Pediatric Solid Tumor Oncology Patients Following Tumor Resection

BACKGROUND

Packed red blood cell (PRBC) transfusion is a lifesaving intervention that also has proinflammatory and immunosuppressive effects. Adults with a malignancy who receive PRBC transfusion have increased rates of infection, tumor recurrence, and decreased survival. The effect of PRBC transfusion among children with solid tumors is unknown.

METHODS

We performed a retrospective review of all children who underwent operative resection of a solid tumor malignancy. Data collected included demographic information, location of operation, nadir hemoglobin, and any PRBC transfusion within 30 days of tumor resection.

RESULTS

Three hundred sixty children underwent tumor resection at our institution between 2002 and 2013; 194 (54%) received a perioperative blood transfusion. After adjusting for stage at diagnosis, tumor location, preoperative chemotherapy and nadir hemoglobin, blood transfusion was associated with a higher rate of postoperative infectious complications, shorter disease-free interval, and a higher rate of tumor recurrence. Each additional transfused unit increased the risk of postoperative infection (odds ratio 3.83; 95% confidence interval 1.21, 14.22, P =0.031).

CONCLUSIONS

Among children with solid tumor malignancies, PRBC transfusion within 30 days of operation is associated with higher rates of postoperative infection. If transfusion becomes necessary, single unit increments should be transfused.

LEVEL OF EVIDENCE

Level III.

Carbapenem-resistant Pseudomonas aeruginosa infections in critically ill children: Prevalence, risk factors, and impact on outcome in a large tertiary pediatric hospital of China

Background and aims

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a major cause of healthcare-associated infections worldwide, but comprehensive study of clinical characteristics for CRPA infections among critically ill children remains limited in China. The objective of this study was to determine the epidemiology, risk factors, and clinical outcomes of CRPA infections among critically ill pediatric patients in a large tertiary pediatric hospital in China.

Methods

A retrospective case-control study of patients with P. aeruginosa infections was conducted in the three intensive care units (ICUs) of Shanghai Children's Medical Center from January 2016 to December 2021. All patients with CRPA infection in the ICUs were enrolled as case patients. Patients with carbapenem-susceptible P. aeruginosa (CSPA) infection were randomly selected as control patients in a ratio of 1:1. Clinical characteristics of those inpatients were reviewed through the hospital information system. Univariate and multivariate analyses were performed to evaluate risk factors associated with the development of CRPA infections and mortality of P. aeruginosa infections.

Results

A total of 528 cases of P. aeruginosa infection in the ICUs were enrolled in the 6-year study. The prevalence of CRPA and MDRPA (multidrug-resistance P. aeruginosa) was 18.4 and 25.6%, respectively. Significant risk factors related to CRPA infection were the length of hospitalization >28 days (OR = 3.241, 95% CI 1.622-6.473, p = 0.001), receiving invasive operations (OR = 2.393, 95% CI 1.196-4.788, p = 0.014) and a blood transfusion (OR = 7.003, 95% CI 2.416-20.297, p < 0.001) within 30 days before infection. Conversely, birth weight ≥2,500 g (OR = 0.278, 95% CI 0.122-0.635, p = 0.001) and breast nursing (OR = 0.362, 95% CI 0.168-0.777, p = 0.009) were significant protective factors against CRPA infections. The in-hospital mortality rate was 14.2%, and no difference in mortality was observed between patients with CRPA and CSPA infections. Platelet < 100 × 10⁹/L (OR = 5.729, 95% CI 1.048-31.308, p = 0.044) and serum urea <3.2 mmol/L (OR = 5.173, 95% CI 1.215-22.023, p = 0.026) were independent predictors for the mortality due to P. aeruginosa infection.

Conclusions

Our findings provide insights into CRPA infections among critically ill children in China. They provide guidance in identifying patients that may be at high risk for a resistant infection and emphasize the importance of antimicrobial stewardship and infection control in hospitals.

Red Blood Cell-Derived Microparticles Exert No Cancer Promoting Effects on Colorectal Cancer Cells In Vitro

The biomedical consequences of allogeneic blood transfusions and the possible pathomechanisms of transfusion-related morbidity and mortality are still not entirely understood. In retrospective studies, allogeneic transfusion was associated with increased rates of cancer recurrence, metastasis and death in patients with colorectal cancer. However, correlation does not imply causation. The purpose of this study was to elucidate this empirical observation further in order to address insecurity among patients and clinicians. We focused on the in vitro effect of microparticles derived from red blood cell units (RMPs). We incubated different colon carcinoma cells with RMPs and analyzed their effects on growth, invasion, migration and tumor marker expression. Furthermore, effects on Wnt, Akt and ERK signaling were explored. Our results show RMPs do not seem to affect functional and phenotypic characteristics of different colon carcinoma cells and did not induce or inhibit Wnt, Akt or ERK signaling, albeit in cell culture models lacking tumor microenvironment. Allogeneic blood transfusions are associated with poor prognosis, but RMPs do not seem to convey tumor-enhancing effects. Most likely, the circumstances that necessitate the transfusion, such as preoperative anemia, tumor stage, perioperative blood loss and extension of surgery, take center stage.

Effect of washed versus unwashed red blood cells on transfusion-related immune responses in preterm newborns

Objectives

Transfusion with washed packed red blood cells (PRBCs) may be associated with reduced transfusion‐related pro‐inflammatory cytokine production. This may be because of alterations in recipient immune responses.

Methods

This randomised trial evaluated the effect of transfusion with washed compared with unwashed PRBCs on pro‐inflammatory cytokines and endothelial activation in 154 preterm newborns born before 29 weeks’ gestation. Changes in plasma cytokines and measures of endothelial activation in recipient blood were analysed after each of the first three transfusions.

Results

By the third transfusion, infants receiving unwashed blood had an increase in IL‐17A (P = 0.04) and TNF (P = 0.007), whereas infants receiving washed blood had reductions in IL‐17A (P = 0.013), TNF (P = 0.048), IL‐6 (P = 0.001), IL‐8 (P = 0.037), IL‐12 (P = 0.001) and IFN‐γ (P = 0.001). The magnitude of the post‐transfusion increase in cytokines did not change between the first and third transfusions in the unwashed group but decreased in the washed group for IL‐12 (P = 0.001), IL‐17A (P = 0.01) and TNF (P = 0.03), with the difference between the groups reaching significance by the third transfusion (P < 0.001 for each cytokine).

Conclusion

The pro‐inflammatory immune response to transfusion in preterm infants can be modified when PRBCs are washed prior to transfusion. Further studies are required to determine whether the use of washed PRBCs for neonatal transfusion translates into reduced morbidity and mortality.

Association between the length of storage of transfused leukoreduced red blood cell units and hospital-acquired infections in critically ill children: A secondary analysis of the TRIPICU study

OBJECTIVE

Evaluate the association between leukoreduced red blood cell (RBC) storage length and hospital-acquired infection (HAI) incidence rate in critically ill children.

BACKGROUND

RBC transfusions are common in critically ill children. Despite their benefits, observational studies suggest an association between them and HAIs. One possible mechanism for increased HAI is transfusion-related immunomodulation due to bioactive substances' release as transfused blood ages.

METHODS

In this secondary analysis of the 'Transfusion Requirement in Paediatric Intensive Care Units' (TRIPICU) study, we analysed a subset of 257 participants that received only one pre-storage leukoreduced RBC transfusion. RBC storage length was classified as 1) transfusion of 'fresh' RBCs (≤10 days), 2) transfusion of 'stored' RBCs (21-34 days), and 3) transfusion of 'long-stored' RBCs (≥35 days). All were compared to a 'golden' period (11-20 days), representing the time between 'fresh' and 'stored'. We used quasi-Poisson multivariable regression models to estimate the HAI incidence rate ratio (IRR) and corresponding 95% confidence interval (CI).

RESULTS

We found that the association between the length of storage time of leukoreduced RBCs and HAIs was not significant in the 'fresh' group (IRR 1.23; 95% CI 0.55, 2.78) and the 'stored' group (IRR 1.61; 95% CI 0.63, 4.13) when compared to the 'golden' period. However, we observed a statistically significant association between the 'long-stored' group and an increase in the HAI incidence rate (IRR 3.66; 95% CI 1.22, 10.98).

CONCLUSION

Transfusion of leukoreduced RBC units stored for ≥35 days is associated with increased HAI incidence rate in haemodynamically stable, critically ill children.

Predictors for Perioperative Blood Transfusion in Patients Undergoing Open Cystectomy and Urinary Diversion and Development of a Nomogram: An Observational Cohort Study

Open radical cystectomy is associated with a substantial rate of perioperative blood transfusion. Early detection of potentially modifiable perioperative factors could reduce the need for perioperative blood transfusion and thus positively impact the outcome. We conducted an observational, single-center cohort study of 1168 patients undergoing cystectomy. Perioperative blood transfusion was defined as the need for packed red blood cells and/or fresh frozen plasma units within the first 24 h after the initiation of surgery. Multiple logistic regression analysis was performed to model the association between risk factors and blood transfusion, and a nomogram was developed. Blood transfusion occurred in 370/1168 patients (31.7%). Significant predictors were age (OR: 1.678, (95% CI: 1.379–2.042); p < 0.001), blood loss ratio (6.572, (4.878–8.853); p < 0.001), preoperative hemoglobin (0.316, (0.255–0.391); p < 0.001), tumor stage (2.067, (1.317–3.244); p = 0.002), use of oral anticoagulants (2.70, (1.163–6.270), p = 0.021), and interaction between female sex and blood loss ratio (1.344, (1.011–1.787); p = 0.042). Of the major predictors found to affect perioperative blood transfusion, two can be influenced: blood loss ratio by meticulous surgery and hemoglobin by preoperative optimization. Others such as age or advanced disease are not modifiable. This emphasizes the importance of optimal management of patients prior to surgery.

Shock Severity Modifies Associations Between RBC Transfusion in the First 48 Hours of Sepsis Onset and the Duration of Organ Dysfunction in Critically Ill Septic Children

OBJECTIVE

To test the hypothesis that early RBC transfusion is associated with duration of organ dysfunction in critically ill septic children.

DESIGN

Secondary analysis of a single-center prospective observational study. Multivariable negative binomial regression was used to determine relationships between RBC transfusion within 48 hours of sepsis onset and number of days in 14 with organ dysfunction, or with multiple organ dysfunction syndrome.

SETTING

A PICU at a quaternary care children's hospital.

PATIENTS

Children less than 18 years old with severe sepsis/septic shock by consensus criteria were included. Patients with RBC transfusion prior to sepsis onset and those on extracorporeal membrane oxygenation support within 48 hours of sepsis onset were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Ninety-four patients were included. Median age was 6 years (0-13 yr); 61% were male. Seventy-eight percentage had septic shock, and 41 (44%) were transfused RBC within 48 hours of sepsis onset (early RBC transfusion). On multivariable analyses, early RBC transfusion was independently associated with 44% greater organ dysfunction days (adjusted relative risk, 1.44 [1.04-2.]; p = 0.03), although risk differed by severity of illness (interaction p = 0.004) and by shock severity (interaction p = 0.04 for Vasoactive Inotrope Score and 0.03 for shock index). Relative risks for multiple organ dysfunction syndrome days varied by shock severity (interaction p = 0.008 for Vasoactive Inotrope Score and 0.01 for shock index). Risks associated with early RBC transfusion were highest for the children with the lowest shock severities.

CONCLUSIONS

In agreement with previous studies, early RBC transfusion was independently associated with longer duration of organ dysfunction. Ours is among the first studies to document different transfusion-associated risks based on clinically available measures of shock severity, demonstrating greater transfusion-associated risks in children with less severe shock. Larger multicenter studies to verify these interaction effects are essential to plan much-needed RBC transfusion trials for critically ill septic children.

The Contribution of Storage Medium and Membranes in the Microwave Dielectric Response of Packed Red Blood Cells Suspension

During cold storage, packed red blood cells (PRBCs) undergo slow detrimental changes that are collectively termed storage lesion. The aging of the cells causes alterations in the composition of the storage-medium in the PRBC unit. In this paper, we present the comparison of the dielectric response of water in the primary (fresh) storage medium (citrate phosphate dextrose adenine solution, CPDA-1) versus the storage medium from three expired units of PRBCs. Dielectric response of the water molecules has been characterized by dielectric spectroscopy technique in the microwave frequency band (0.5–40 GHz). The dominant phenomenon is the significant increase of the dielectric strength and decrease the relaxation time τ for the samples of the stored medium in comparison with the fresh medium CPDA-1. Furthermore, we demonstrated that removing the ghosts from PRBC hemolysate did not cause the alteration of the dielectric spectrum of water. Thus, the contribution associated with water located near the cell membrane can be neglected in microwave dielectric measurements.

Blood transfusions during neoadjuvant chemotherapy for muscle-invasive urinary bladder cancer may have a negative impact on overall survival

Objective: To evaluate the extent and plausible effects of blood transfusions given during cisplatin-based neoadjuvant chemotherapy (NAC) on overall survival in patients with muscle-invasive urothelial bladder cancer (MIBC) undergoing NAC and radical cystectomy (RC).Background: Several studies have demonstrated a decreased survival for MIBC patients receiving allogenic peri- and postoperative blood transfusions in conjunction with RC. No studies have previously investigated the effects of blood transfusions during NAC.Materials and methods: 120 patients with MIBC (cT2-T4aN0M0) undergoing NAC and RC between 2008 and 2014 at four Swedish cystectomy centers were retrospectively evaluated. Clinicopathological data were obtained, including data of allogenic blood administration. Survival data was analyzed by Kaplan-Meier plotting and Cox regression.Results: One third of the cohort received blood transfusions during the period of NAC. In univariate analysis, blood transfusions during NAC, nodal stage and advanced tumor stage (pT >2) were negative prognostic factors for survival. In multivariate analysis, only pNx and pT >2 remained significant negative prognostic factors. In a subgroup analysis consisting of patients with localized tumors without dissemination (n = 96), patients that received transfusions during NAC showed an 18.5% absolute risk increase of death at five years of observation, although without statistical significance (p = .197).Conclusions: This is the first time that the extent and plausible effects of allogenic blood transfusions during NAC is examined in MIBC. Data suggest that there may be an association between blood transfusion and poor pathological and oncological outcome. Firm conclusions are difficult to draw due to few study participants and the retrospective nature of the study.

Impact of transfusion on survival in patients with myelodysplastic syndromes: Current knowledge, new insights and transfusion clinical practice

Red Blood Cell (RBC) transfusion dependence is a prevalent consequence of anaemia in patients with lower risk Myelodysplastic Syndromes (MDS). These patients have shorter survival compared to patients responding to Erythropoiesis-stimulating agents (ESA), raising the question of potential negative effects of chronic RBC transfusions on MDS prognosis, independently of IPSS-R. Besides commonly identified complications of transfusions like iron toxicity or cardiac events, oxidative stress could be a risk factor for ineffective haematopoiesis. Recently, physicochemical changes of RBC during storage have been described. These changes called storage lesions could play a role in immunomodulation in vivo. We review the currently identified sources of potential impact on transfusion-associated effects in MDS patients and we discuss the unexplored potential role of erythrocyte-derived-extracellular vesicles. They could amplify impairment of haematopoiesis in addition to the negative intrinsic effects underlying the pathology in MDS. Thus, chronic RBC transfusions appear to potentially impact the outcome of MDS.

Packed Red Blood Cell Transfusion Modulates Myeloid Dendritic Cell Activation and Inflammatory Response In Vitro

Transfusion of packed red blood cells (PRBCs) modulates patients' immune responses and clinical outcomes; however, the underpinning mechanism(s) remain unknown. The potential for PRBC to modulate myeloid dendritic cells (mDC) and blood DC antigen 3 was assessed using an in vitro transfusion model. In parallel, to model processes activated by viral or bacterial infection, toll-like receptor agonists polyinosinic:polycytidylic acid or lipopolysaccharide were added. Exposure to PRBC upregulated expression of CD83 and downregulated CD40 and CD80 on both DC subsets, and it suppressed production of interleukin (IL)-6, IL-8, IL-12, tumor necrosis factor-α, and interferon-gamma-inducible protein-10 by these cells. Similar effects were observed when modeling processes activated by concurrent infection. Furthermore, exposure to PRBC at date of expiry was associated with more pronounced effects in all assays. Our study suggests PRBC have an impact on recipient DC function, which may result in failure to establish an appropriate immune response, particularly in patients with underlying infection.

Red blood cell transfusion and its alternatives in oncologic surgery-A critical evaluation

Although blood transfusions have been used for more than 100 years and their potential to save lives is indisputable, there is still limited data on medium- and long-term outcomes after hemotherapy. Until recently, red blood cell transfusions represented the most commonly employed treatment for cancer anemia. As transfusions have been related to worse patient outcome in oncologic surgery, preventive strategies and alternative treatment approaches in the perioperative setting are warranted. This review aims to evaluate the evidence concerning the impact of transfusion on the course of malignant diseases with a focus on oncologic surgery and to provide a bundle of measures to improve patient care. The perioperative period is pivotal in determining long-term cancer outcome. An increasingly recognized area for improvement during this highly sensitive period is the treatment of anemia for three main reasons: Firstly, anemia has been recognized as an independent predictor of poor prognosis in cancer patients. Secondly, anemia is largely undertreated. Thirdly and probably most importantly, anemia therapy relied and often still relies heavily on red blood cell (RBC) transfusions, which may be an often suboptimal stopgap treatment. Perioperative RBC transfusions should be kept to a minimum due to growing concerns regarding the associated risks, which this review tries to clarify by providing an update of recent literature. This review furthermore discusses treatments for anemia and provides best-practice approaches to improve perioperative management of oncology patients undergoing surgery.

Trauma-Induced Damage-Associated Molecular Patterns-Mediated Remote Organ Injury and Immunosuppression in the Acutely Ill Patient

Trauma is one of the leading causes of death and disability in the world. Multiple trauma or isolated traumatic brain injury are both indicative of human tissue damage. In the early phase after trauma, damage-associated molecular patterns (DAMPs) are released and give rise to sterile systemic inflammatory response syndrome (SIRS) and organ failure. Later, protracted inflammation following sepsis will favor hospital-acquired infection and will worsen patient’s outcome through immunosuppression. Throughout medical care or surgical procedures, severe trauma patients will be subjected to endogenous or exogenous DAMPs. In this review, we summarize the current knowledge regarding DAMP-mediated SIRS or immunosuppression and the clinical consequences in terms of organ failure and infections.

Effect of storage period of red blood cell suspensions on helper T-cell subpopulations

BACKGROUND

The aim of this study was to investigate the immunological alterations that occur during the storage of erythrocyte suspensions which may lead to transfusion-related immunomodulation following allogeneic blood transfusion.

MATERIALS AND METHODS

One part of the erythrocyte suspensions obtained from donors was leucoreduced while the other part was not. The leucoreduced (LR) and non-leucoreduced (NL) erythrocyte suspensions were then further divided into three equal amounts which were stored for 0, 21 or 42 days prior to measurements, by enzyme-linked immunosorbent assays, of cytokine levels in their supernatants. T-helper (Th) lymphocyte subgroups and gene expression were analysed in the NL erythrocyte suspensions by flow cytometry and real-time polymerase chain reaction, respectively. Results were compared to those of storage day 0.

RESULTS

By day 21, the number of Th2 cells had increased significantly and the numbers of Th1, Th22 and Treg cells had decreased significantly in the NL erythrocyte suspensions. On day 42 the numbers of Th2 and Treg cells in the NL suspensions were significantly increased while the number of Th1 cells was significantly decreased. The levels of transcription factors (TBX21, GATA3, and SPI.1) were significantly decreased on days 21 and 42, and AHR, FOXP3 and RORC2 levels were significantly increased on day 42 in NL erythrocyte suspensions. The decrease in interleukin-22 and increase in transforming growth factor-β levels found in NL erythrocyte suspensions on day 21 were statistically significant. Elevated levels of interleukin-17A were found in both LR and NL erythrocyte suspensions on day 42.

DISCUSSION

Our results suggest that allogeneic leucocytes and cytokines may play significant roles in the development of transfusion-related immunomodulation.

Mechanisms of red blood cell transfusion-related immunomodulation

Red blood cell (RBC) transfusion is common in critically ill, postsurgical, and posttrauma patients in whom both systemic inflammation and immune suppression are associated with adverse outcomes. RBC products contain a multitude of immunomodulatory mediators that interact with and alter immune cell function. These interactions can lead to both proinflammatory and immunosuppressive effects. Defining clinical outcomes related to immunomodulatory effects of RBCs in transfused patients remains a challenge, likely due to complex interactions between individual blood product characteristics and patient-specific risk factors. Unpacking these complexities requires an in-depth understanding of the mechanisms of immunomodulatory effects of RBC products. In this review, we outline and classify potential mediators of RBC transfusion-related immunomodulation and provide suggestions for future research directions.

Transfusion Decision Making in Pediatric Critical Illness

Transfusion decision making (TDM) in the critically ill requires consideration of: (1) anemia tolerance, which is linked to active pathology and to physiologic reserve, (2) differences in donor RBC physiology from that of native RBCs, and (3) relative risk from anemia-attributable oxygen delivery failure vs hazards of transfusion, itself. Current approaches to TDM (e.g. hemoglobin thresholds) do not: (1) differentiate between patients with similar anemia, but dissimilar pathology/physiology, and (2) guide transfusion timing and amount to efficacy-based goals (other than resolution of hemoglobin thresholds). Here, we explore approaches to TDM that address the above gaps.

Perioperative red blood cell transfusion in orofacial surgery

In the field of orofacial surgery, a red blood cell transfusion (RBCT) is occasionally required during double jaw and oral cancer surgery. However, the question remains whether the effect of RBCT during the perioperative period is beneficial or harmful. The answer to this question remains challenging. In the field of orofacial surgery, transfusion is performed for the purpose of oxygen transfer to hypoxic tissues and plasma volume expansion when there is bleeding. However, there are various risks, such as infectious complications (viral and bacterial), transfusion-related acute lung injury, ABO and non-ABO associated hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions, transfusion associated graft-versus-host disease, transfusion associated circulatory overload, and hypersensitivity transfusion reaction including anaphylaxis and transfusion-related immune-modulation. Many studies and guidelines have suggested RBCT is considered when hemoglobin levels recorded are 7 g/dL for general patients and 8-9 g/dL for patients with cardiovascular disease or hemodynamically unstable patients. However, RBCT is occasionally an essential treatment during surgeries and it is often required in emergency cases. We need to comprehensively consider postoperative bleeding, different clinical situations, the level of intra- and postoperative patient monitoring, and various problems that may arise from a transfusion, in the perspective of patient safety. Since orofacial surgery has an especially high risk of bleeding due to the complex structures involved and the extensive vascular distribution, measures to prevent bleeding should be taken and the conditions for a transfusion should be optimized and appropriate in order to promote patient safety.

Impact of Packed Red Blood Cells and Fresh Frozen Plasma Given During Radical Cystectomy and Urinary Diversion on Cancer-related Outcome and Survival: An Observational Cohort Study

BACKGROUND

The relationship between blood transfusion and cancer-related outcome and mortality is controversial.

OBJECTIVE

To assess if perioperative administration of packed red blood cell (PRBC) and fresh frozen plasma (FFP) units affects disease progression and survival after radical cystectomy for bladder cancer.

DESIGN, SETTING, AND PARTICIPANTS

We conducted an observational single-centre cohort study of a consecutive series of 885 bladder cancer patients, between 2000 and 2015. Perioperative blood transfusion was defined as need for PRBCs and FFP transfusion within the first 24h after the beginning of surgery.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Disease recurrence-free, cancer-specific, and overall survival were estimated using the Kaplan-Meier technique and log-rank test.

RESULTS AND LIMITATIONS

A total of 267/885 patients (23%) were transfused; 187/267 patients (70%) received only PRBCs (median 2 units [interquartile range: 1-2]) and 80/267 patients (30%) received PRBCs (2 [2-3]) plus FFP (2 [2-2]). Receipt of PRBCs or PRBCs+FFP was associated with a higher 90 d mortality (7.0% vs 7.5% vs 2.9%; p=0.016), inferior 5 yr recurrence-free survival (no transfusion 92%, PRBCs 74%, p=0.005; PRBCs+FFP 49%, p=0.002), 5 yr cancer-specific survival (no transfusion 74%, PRBCs 60%, PRBCs+FFP 49%, all p<0.001), and 5 yr overall survival (no transfusion 90%, PRBCs 70%, PRBCs+FFP 34%, all p<0.001). In multivariate analysis, blood transfusion was predictive for all-cause mortality (PRBCs [hazard ratio; HR 1.610; p<0.001] and PRBCs+FFP [HR 1.640; p=0.003]) and cancer-specific mortality (PRBCs [HR 1.467; p=0.010] and PRBCs+FFP [HR 1.901; p=0.021]). Limitations include selection bias and lack of standardised transfusion criteria.

CONCLUSIONS

Administration of PRBCs and FFP was associated with significantly inferior cancer-specific and overall survival. Relevant preoperative factors for receiving blood transfusion were neoadjuvant chemotherapy, preoperative anaemia, older age, and American Society of Anesthesiologists score ≥3, and these factors emphasise the importance of preoperative optimisation of patients undergoing cystectomy.

PATIENT SUMMARY

Blood transfusion during radical cystectomy was associated with inferior survival.

Balance Between the Proinflammatory and Anti-Inflammatory Immune Responses with Blood Transfusion in Sepsis

Blood product transfusion may exacerbate the initial immunosuppressive response of sepsis. Nurses and other patient care providers must be diligent in recognizing and managing a worsening immune status, using flow cytometry to monitor patients' immune status. This type of monitoring may be instrumental in reducing morbidity and mortality in persons with sepsis. This article discusses the recent literature on the associated inflammatory responses that occur with blood transfusion and provides an analysis of alterations in key inflammatory pathways in response to transfusion in a sepsis population.

Transfusion-related immunomodulation and cancer

Blood and blood-component therapy triggers immunological reactions in recipients. Transfusion-related immunomodulation [TRIM] is an important complex biological immune reaction to transfusion culminating in immunosuppression. The mechanisms underlying TRIM include the presence of residual leukocytes and apoptotic cells, the transfusion of immunosuppressive cytokines either present in donor components or generated during blood processing, the transfer of metabolically active growth factor-loaded microparticles and extracellular vesicles and the presence of free hemoglobin or extracellular vesicle-bound hemoglobin. TRIM variables include donor-specific factors as well as processing variables. TRIM may explain, at least in part, the controversial negative clinical outcomes observed in cancer patients receiving transfusion in the context of curative-intent surgeries. The use of novel technologies including metabolomics and proteomics on stored blood may pave the way for a deeper understanding of TRIM in general and its impact on cancer progression.

Red blood cell transfusion in surgical cancer patients: Targets, risks, mechanistic understanding and further therapeutic opportunities

Anemia is present in more than half of cancer patients and appears to be an independent prognostic factor of short- and long-term adverse outcomes. It increases in the advanced period of cancer and perioperatively, in patients with solid tumors who undergo surgery. As a result, allogeneic red blood cell (RBC) transfusion is an indispensable treatment in cancer. However, its safety remains controversial, based on several laboratory and clinical data reporting a linkage with increased risk for cancer recurrence, infection and cancer-related mortality. Immunological, inflammatory and thrombotic reactions mediated by the residual leukocytes and platelets, the stored RBCs per se, the biological response modifiers and the plasticizer of the unit may underlie infection and tumor-promoting effects. Although the causality between transfusion and infection has been established, the effects of transfusion on cancer recurrence remain confusing; this is mainly due to the extreme biological heterogeneity that characterizes RBC donations and cancer context. In fact, the functional interplay between donation-associated factors and recipient characteristics, including tumor biology per se, inflammation, infection, coagulation and immune activation state and competence may synergistically and individually define the clinical impact of each transfusion in any given cancer patient. Our understanding of how the potential risk is mediated is important to make RBC transfusion safer and to pave the way for novel, promising and highly personalized strategies for the treatment of anemia in surgical cancer patients.

Transfusion-related immunomodulation: review of the literature and implications for pediatric critical illness

Transfusion-related immunomodulation (TRIM) in the intensive care unit (ICU) is difficult to define and likely represents a complicated set of physiologic responses to transfusion, including both proinflammatory and immunosuppressive effects. Similarly, the immunologic response to critical illness in both adults and children is highly complex and is characterized by both acute inflammation and acquired immune suppression. How transfusion may contribute to or perpetuate these phenotypes in the ICU is poorly understood, despite the fact that transfusion is common in critically ill patients. Both hyperinflammation and severe immune suppression are associated with poor outcomes from critical illness, underscoring the need to understand potential immunologic consequences of blood product transfusion. In this review we outline the dynamic immunologic response to critical illness, provide clinical evidence in support of immunomodulatory effects of blood product transfusion, review preclinical and translational studies to date of TRIM, and provide insight into future research directions.

Red Blood Cell Transfusion in the Emergency Department

BACKGROUND

Transfusion of red blood cells (RBCs) is the primary management of anemia, which affects 90% of critically ill patients. Anemia has been associated with a poor prognosis in various settings, including critical illness. Recent literature has shown a hemoglobin transfusion threshold of 7 g/dL to be safe. This review examines several aspects of transfusion.

OBJECTIVE

We sought to provide emergency physicians with an updated review of indications for RBC transfusion in the emergency department.

DISCUSSION

The standard hemoglobin transfusion threshold was 10 g/dL. However, the body shows physiologic compensatory adaptations to chronic anemia. Transfusion reactions and infections are rare but can have significant morbidity and mortality. Products stored for <21 days have the lowest risk of reaction and infection. A restrictive threshold of 7 g/dL is recommended in the new American Association of Blood Banks guidelines and multiple meta-analyses and supported in gastrointestinal bleeding, sepsis, critical illness, and trauma. Patients with active ischemia in acute coronary syndrome and neurologic injury require additional study. The physician must consider the patient's hemodynamic status, comorbidities, risks and benefits of transfusion, and clinical setting in determining the need for transfusion.

CONCLUSIONS

RBC transfusion is not without risks, including transfusion reaction, infection, and potentially increased mortality. The age of transfusion products likely has no effect on products before 21 days of storage. A hemoglobin level of 7 g/dL is safe in the setting of critical illness, sepsis, gastrointestinal bleeding, and trauma. The clinician must evaluate and transfuse based on the clinical setting and patient hemodynamic status rather than using a specific threshold.

Sterile post-traumatic immunosuppression

After major trauma, the human immune system initiates a series of inflammatory events at the injury site that is later followed by suppression of local inflammation favoring the repair and remodeling of the damaged tissues. This local immune response involves complex interactions between resident cells such as macrophages and dendritic cells, soluble mediators such as cytokines and chemokines, and recruited cells such as neutrophils, monocytes and mesenchymal stromal cells. If of sufficient magnitude, these initial immune responses nevertheless have systemic consequences resulting in a state called post-traumatic immunosuppression (PTI). However, controversy exists regarding the exact immunological changes occurring in systemic compartments triggered by these local immune responses. PTI is one of the leading causes of post-surgical mortality and makes patients vulnerable to hospital-acquired infections, multiple organ failure and many other complications. In addition, hemorrhage, blood transfusion, immunesenescence and immunosuppressant drugs aggravate PTI. PTI has been intensively studied, but published results are frequently cloudy. The purpose of this review is to focus on the contributions made by different responsive modalities to immunosuppression following sterile trauma and to try to integrate these into an overall scheme of PTI.

Neonatal Transfusion Medicine: Five Major Unanswered Research Questions for the Twenty-First Century

Blood component transfusions are important to the care of preterm neonates; however, their use in clinical practice often is not based on high levels of evidence. Five major questions for neonates are discussed: (1) What is the optimal red blood cell (RBC) transfusion threshold? (2) What is the optimal platelet transfusion threshold? (3) Does the storage age of an RBC unit affect outcomes? (4) Does RBC transfusion contribute to the pathogenesis of necrotizing enterocolitis? and (5) Which new practices should be used to prevent transfusion-transmitted infections? Although definitive answers to these questions do not exist, future research should help answer them.

Clinical Outcomes Associated With RBC Transfusions in Critically Ill Children: A 1-Year Prospective Study

OBJECTIVE

To identify the potential complications associated with RBC transfusions.

DESIGN

Prospective observational study.

SETTING

PICU in a tertiary children's hospital.

PATIENTS

All children consecutively admitted to our PICU during a 1-year period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data were abstracted from medical charts prospectively. Outcomes possibly attributable to RBC transfusions were looked for daily. In transfused cases, it was considered that an outcome was associated with a transfusion only if it was observed after the first RBC transfusion. During the 1-year study period, 913 consecutive admissions were documented, 842 of which were included. Among them, 144 (17%) were transfused at least once. When comparing transfused cases with nontransfused cases, the odds ratio for new or progressive multiple organ dysfunction syndrome was 5.14 (95% CI, 3.28-8.06; p < 0.001). This association remained statistically significant in the multivariable analysis (odds ratio, 3.85; 95% CI, 2.38-6.24; p < 0.001). Transfused cases were ventilated longer than nontransfused cases (14.1 ± 32.6 vs 4.3 ± 9.6 d, p < 0.001), even after adjustment in a Cox model. The PICU length of stay was significantly increased for transfused cases (12.4 ± 26.2 vs 4.9 ± 10.2 d, p < 0.001), even after controlling for potential confounders. The paired analysis for comparison of pretransfusion and posttransfusion values showed that the arterial partial pressure in oxygen was significantly reduced within the 6 hours after the first RBC transfusion (mean difference, 25.6 torr, 95% CI, 5.7-45.4; p = 0.029). The paired analysis also showed an increased proportion of renal replacement therapy.

CONCLUSIONS

RBC transfusions in critically ill children were associated with prolonged mechanical ventilation and prolonged PICU stay. The risk of new or progressive multiple organ dysfunction syndrome was also increased in some transfused children. Furthermore, our study questions the ability of stored RBCs to improve oxygenation in critically ill children. Practitioners should take into account these data when prescribing an RBC transfusion to PICU patients.

Renitrosylation of banked human red blood cells improves deformability and reduces adhesivity

BACKGROUND

Transfusion of red blood cells (RBCs) is a frequent health care practice. However, unfavorable consequences may occur from transfusions of stored RBCs and are associated with RBC changes during storage. Loss of S-nitrosohemoglobin (SNO-Hb) and other S-nitrosothiols (SNOs) during storage is implicated as a detriment to transfusion efficacy. It was hypothesized that restoring SNOs within banked RBCs would improve RBC functions relevant to successful transfusion outcomes, namely, increased deformability and decreased adhesivity.

STUDY DESIGN AND METHODS

Stored human RBCs were incubated with nitric oxide (NO) donors PROLI/NO and DEA/NO (disodium 1-[2-(carboxylato)-pyrrolidin-1-yl]diazen-1-ium-1,2-diolate and diethylammonium (Z)-1-(N,N-diethylamino)diazen-1-ium-1,2-diolate) under varying experimental conditions (e.g., aerobic/anaerobic incubation, NO donor to RBC ratio). SNO restoration was evaluated in vitro and in vivo as a means to improve RBC function after storage.

RESULTS

Incubation of RBCs with the NO donors resulted in 10-fold greater levels of SNO-Hb versus untreated control or sham RBCs, with significantly higher Hb-bound NO yields from an NO dose delivered by DEA/NO. RBC incubation with DEA/NO at a stoichiometry of 1:62.5 NO:Hb significantly increased RBC deformabilty and reduced adhesion to cultured endothelial cells. RBC incubation with DEA/NO also increased S-nitrosylation of RBC cytoskeletal and membrane proteins, including the β-spectrin chain. Renitrosylation attenuated both RBC sequestration in the lung and the mild blood oxygen saturation impairments seen with banked RBCs in a mouse model of transfusion.

CONCLUSIONS

RBC renitrosylation using NO donors has promise for correcting deficient properties (e.g., adhesivity, rigidity, and SNO loss) of banked RBCs and in turn improving transfusion outcomes.

Red blood cell transfusion and immune function in critically ill children: a prospective observational study

BACKGROUND

Our previous in vitro work showed that stored red blood cells (RBCs) increasingly suppress markers of innate immune function with increased storage time. This multicenter prospective observational study tests the hypothesis that a single RBC transfusion in critically ill children is associated with immune suppression as a function of storage time.

STUDY DESIGN AND METHODS

Blood samples were taken immediately before and 24 (±6) hours after a single RBC transfusion ordered as part of routine care. Innate and adaptive immune function was assessed by ex vivo whole blood stimulation with lipopolysaccharide (LPS) and phytohemagglutinin, respectively. Monocyte HLA-DR expression, regulatory T cells, plasma interleukin (IL)-6, and IL-8 levels were also measured.

RESULTS

Thirty-one transfused critically ill children and eight healthy controls were studied. Critically ill subjects had lower pretransfusion LPS-induced tumor necrosis factor-α production capacity compared to healthy controls, indicating innate immune suppression (p < 0.0002). Those who received RBCs stored for not more than 21 days demonstrated recovery of innate immune function (p = 0.02) and decreased plasma IL-6 levels (p = 0.002) over time compared to children transfused with older blood, who showed persistence of systemic inflammation and innate immune suppression. RBC storage time was not associated with changes in adaptive immune function.

CONCLUSION

In this pilot cohort of critically ill children, transfusion with older prestorage leukoreduced RBCs was associated with persistence of innate immune suppression and systemic inflammation. This was not seen with fresher RBCs. RBC transfusion had no short-term association with adaptive immune function. Further studies are warranted to confirm these findings in a larger cohort of patients.

Biochemical assessment of red blood cells during storage by (1)H nuclear magnetic resonance spectroscopy. Identification of a biomarker of their level of protection against oxidative stress

BACKGROUND

Blood transfusion is an established therapeutic practice. The characteristics of blood components at different storage times are expected to affect the efficacy of transfusion therapy. Metabolic profiling by nuclear magnetic resonance (NMR) spectroscopy requires little or no sample treatment and allows identification of more than 50 soluble metabolites in a single experiment. The aim of this study was to assess the metabolic behaviour of red blood cells during 42 days of storage in blood bank conditions.

MATERIALS AND METHODS

Red blood cells (RBC), collected from eight healthy male donors, aged 25-50 years, were prepared as prestorage leukoreduced erythrocyte concentrates and stored under standard blood bank conditions. Samples taken at various storage times were separated in two fractions: the supernatant, recovered after centrifugation, and the red blood cell lysate obtained after protein depletion by ultrafiltration. The metabolic profile of the red blood cells was determined from analysis of (1)H-NMR spectra.

RESULTS

The red blood cell supernatant was studied to track the consumption of the preservative additives and to detect and quantify up to 30 metabolites excreted by the erythrocytes. The NMR spectra of the RBC lysate provided complementary information on some biochemical pathways and set the basis for building a time-dependent red blood cell metabolic profile.

DISCUSSION

We proved the analytical power of (1)H-NMR spectroscopy to study red blood cell metabolism under blood bank conditions. A potential biomarker able to provide information on the level of cellular oxidative stress protection was identified. Our data support the hypothesis that a more detailed knowledge of metabolic modifications during storage opens the way to the development of new and more effective protocols for red blood cell conservation and patient-oriented transfusion therapy.

T-cell suppression by red blood cells is dependent on intact cells and is a consequence of blood bank processing

BACKGROUND

Red blood cells (RBCs) suppress T-cell responsiveness through a mechanism requiring cell-cell contact. Questions remain as to whether this effect is an allogeneic response, related to cell death, or dependent on particular components of the RBCs.

STUDY DESIGN AND METHODS

Peripheral T cells were isolated from healthy donors and exposed to stored allogeneic RBCs or autologous RBCs after processing. RBCs were lysed by hypotonic solvent to produce cellular ghosts. Tritiated thymidine proliferation assays were utilized. Cultures were saturated with interleukin (IL)-2 to determine whether impaired IL-2 synthesis played a role.

RESULTS

T-cell proliferation was suppressed by both autologous and allogeneic RBCs. RBC membrane integrity does enhance T-cell suppression. T-cell death is not responsible for the suppressive changes. IL-2 synthesis is suppressed in RBC-exposed T cells but addition of exogenous IL-2 does not rescue proliferative capabilities. Proliferation of T cells was inhibited with RBC exposure but mitigated with the addition of fresh RBCs.

CONCLUSIONS

T-cell suppression is enhanced by intact RBCs but this effect is unrelated solely to alloantigens. Neither apoptosis nor necrosis of T cells contributes to this phenomenon. IL-2 synthesis is suppressed after RBC exposure as a consequence of T-cell inhibition, but is not the primary cause of suppression. Fresh RBCs do not mediate T-cell suppression, indicating that changes in the RBC and development of the storage lesion may occur during initial blood bank processing.

Inflammatory response, immunosuppression, and cancer recurrence after perioperative blood transfusions

Debate on appropriate triggers for transfusion of allogeneic blood products and their effects on short- and long-term survival in surgical and critically ill patients continue with no definitive evidence or decisive resolution. Although transfusion-related immune modulation (TRIM) is well established, its influence on immune competence in the recipient and its effects on cancer recurrence after a curative resection remains controversial. An association between perioperative transfusion of allogeneic blood products and risk for recurrence has been shown in colorectal cancer in randomized trials; whether the same is true for other types of cancer remains to be determined. This article focuses on the laboratory, animal, and clinical evidence to date on the mechanistic understanding of inflammatory and immune-modulatory effects of blood products and their significance for recurrence in the cancer surgical patient.

Age of red blood cells and transfusion in critically ill patients

Red blood cells (RBC) storage facilitates the supply of RBC to meet the clinical demand for transfusion and to avoid wastage. However, RBC storage is associated with adverse changes in erythrocytes and their preservation medium. These changes are responsible for functional alterations and for the accumulation of potentially injurious bioreactive substances. They also may have clinically harmful effects especially in critically ill patients. The clinical consequences of storage lesions, however, remain a matter of persistent controversy. Multiple retrospective, observational, and single-center studies have reported heterogeneous and conflicting findings about the effect of blood storage duration on morbidity and/or mortality in trauma, cardiac surgery, and intensive care unit patients. Describing the details of this controversy, this review not only summarizes the current literature but also highlights the equipoise that currently exists with regard to the use of short versus current standard (extended) storage duration red cells in critically ill patients and supports the need for large, randomized, controlled trials evaluating the clinical impact of transfusing fresh (short duration of storage) versus older (extended duration of storage) red cells in critically ill patients.

Effect of processing and storage on red blood cell function in vivo

Red blood cell (RBC) transfusion is indicated to improve oxygen delivery to tissue, and for no other purpose. We have come to appreciate that donor RBCs are fundamentally altered during processing and storage in a manner that both impairs oxygen transport efficacy and introduces additional risk by perturbing both immune and coagulation systems. The protean biophysical and physiological changes in RBC function arising from storage are termed the "storage lesion;" many have been understood for some time; for example, we know that the oxygen affinity of stored blood rises during the storage period and that intracellular allosteric regulators, notably 2,3-bisphosphoglyceric acid and ATP, are depleted during storage. Our appreciation of other storage lesion features has emerged with improved understanding of coagulation, immune, and vascular signaling systems. Here, we review key features of the "storage lesion." Additionally, we call particular attention to the newly appreciated role of RBCs in regulating linkage between regional blood flow and regional O(2) consumption by regulating the bioavailability of key vasoactive mediators in plasma, and discuss how processing and storage disturb this key signaling function and impair transfusion efficacy.

A pilot feasibility trial of allocation of freshest available red blood cells versus standard care in critically ill patients

BACKGROUND

Prolonged storage of red blood cells (RBCs) may increase posttransfusion adverse events in critically ill patients. We aimed to evaluate in intensive care unit (ICU) patients 1) the feasibility of allocating freshest available compatible RBCs versus standard care and 2) the suitability of this approach in the design of a large randomized controlled trial (RCT).

STUDY DESIGN AND METHODS

Eligible patients from two adult ICUs were randomly assigned to receive either the freshest available compatible RBCs or the standard care (the oldest compatible available RBCs) for all transfusions during their ICU stay. Study group allocation was concealed from patients and bedside clinicians, but the transfusion service was unblinded. The study endpoints were the feasibility of the study procedures, including success of the ICU Web randomization, the ICU staff blinding, and the correct delivery of the RBC units by the transfusion service in accordance with the allocated study group. In addition, we measured the difference in age of RBC units between the two groups.

RESULTS

During a 3-month period, 177 RBC units were delivered to 51 patients. All study procedures, including randomization, blinding, and delivery of blood in accordance with the study group were successful. The mean (±SD) of the mean age of the RBC received by each patient was lower in the "fresher blood" group compared with the standard care group (12.1 [±3.8] days vs. 23 [±8.4] days; p<0.001).

CONCLUSION

Randomized delivery of the freshest available RBCs versus standard care to ICU patients who were prescribed transfusion for clinical reasons is feasible, with a clinically relevant degree of storage duration separation achievable between the two study groups. These findings support the feasibility of a future large pragmatic RCT.

Immunosuppressive effects of red blood cells on monocytes are related to both storage time and storage solution

BACKGROUND

Reduced monocyte function is associated with adverse outcomes from critical illness. Red blood cells (RBCs) are thought to impair monocyte function but relationships between RBC storage solution and monocyte suppression are unknown. This study was designed to test the hypothesis that immunosuppressive effects of RBCs on monocytes are related to both storage time and preservative solution.

STUDY DESIGN AND METHODS

Monocytes from healthy adult donors were co-cultured with RBCs that had been stored in AS-1, AS-3, or CPD only for 7, 14, or 21 days. Cells were then stimulated with lipopolysaccharide (LPS) and their supernatants assayed for tumor necrosis factor (TNF)-α and interleukin (IL)-10. Transwell experiments were performed to evaluate the role of cell-to-cell contact. Monocyte mRNA expression was quantified by real-time-polymerase chain reaction.

RESULTS

LPS-induced TNF-α production capacity was reduced compared to controls for all groups, but CPD-only RBCs suppressed monocyte function more than RBCs stored in AS-1 (p = 0.007) and AS-3 (p = 0.006). IL-10 production was preserved or augmented in all groups. A longer storage time was associated with reduced TNF-α production capacity for AS-1 and AS-3 groups but not CPD. Preventing cell-to-cell contact did not eliminate the inhibitory effect of RBCs on monocyte responsiveness. RBC exposure was associated with decreased LPS-induced TNFA mRNA expression (p < 0.05 for all groups).

CONCLUSIONS

CPD-only RBCs suppressed monocyte function more than RBCs stored with additive solutions. TNF-α production was reduced even in the absence of cell-to-cell contact and was impaired at the mRNA level. Further work is needed to understand the role of preservative solutions in this process.

Red blood cell transfusion thresholds in pediatric patients with sepsis

OBJECTIVES

In children with severe sepsis or septic shock, the optimal red blood cell transfusion threshold is unknown. We analyzed the subgroup of patients with sepsis and transfusion requirements in a pediatric intensive care unit study to determine the impact of a restrictive vs. liberal transfusion strategy on clinical outcome.

DESIGN

Subgroup analysis of a prospective, multicenter, randomized, controlled trial.

SETTING

Multicenter pediatric critical care units.

PATIENTS

Stabilized critically ill children (mean systemic arterial pressure >2 sd below normal mean for age and cardiovascular support not increased for at least 2 hrs before enrollment) with a hemoglobin ≤ 9.5 g/dL within 7 days after pediatric critical care unit admission.

INTERVENTIONS

One hundred thirty-seven stabilized critically ill children with sepsis were randomized to receive red blood cell transfusion if their hemoglobin decreased to either <7.0 g/dL (restrictive group) or 9.5 g/dL (liberal group).

MEASUREMENTS AND MAIN RESULTS

In the restrictive group (69 patients), 30 patients did not receive any red blood cell transfusion, whereas only one patient in the liberal group (68 patients) never underwent transfusion (p < .01). No clinically significant differences were found for the occurrence of new or progressive multiple organ dysfunction syndrome (18.8% vs. 19.1%; p = .97), for pediatric critical care unit length of stay (p = .74), or for pediatric critical care unit mortality (p = .44) in the restrictive vs. liberal group.

CONCLUSIONS

In this subgroup analysis of children with stable sepsis, we found no evidence that a restrictive red cell transfusion strategy, as compared to a liberal one, increased the rate of new or progressive multiple organ dysfunction syndromes. Furthermore, a restrictive transfusion threshold significantly reduced exposure to blood products. Our data suggest that a hemoglobin level of 7.0 g/dL may be safe stabilized for children with sepsis, but further studies are required to support this recommendation.

Computerized physician order entry with decision support decreases blood transfusions in children

OBJECTIVE

Timely provision of evidence-based recommendations through computerized physician order entry with clinical decision support may improve use of red blood cell transfusions (RBCTs).

METHODS

We performed a cohort study with historical controls including inpatients admitted between February 1, 2008, and January 31, 2010. A clinical decision-support alert for RBCTs was constructed by using current evidence. RBCT orders resulted in assessment of the patient's medical record with prescriber notification if parameters were not within recommended ranges. Primary end points included the average pretransfusion hemoglobin level and the rate of RBCTs per patient-day.

RESULTS

In total, 3293 control discharges and 3492 study discharges were evaluated. The mean (SD) control pretransfusion hemoglobin level in the PICU was 9.83 (2.63) g/dL (95% confidence interval [CI]: 9.65-10.01) compared with the study value of 8.75 (2.05) g/dL (95% CI: 8.59-8.90) (P < .0001). The wards' control value was 7.56 (0.93) g/dL (95% CI: 7.47-7.65), the study value was 7.14 (1.01) g/dL (95% CI: 6.99-7.28) (P < .0001). The control PICU rate of RBCTs per patient-day was 0.20 (0.11) (95% CI: 0.13-0.27), the study rate was 0.14 (0.04) (95% CI: 0.11-0.17) (P = .12). The PICU's control rate was 0.033 (0.01) (95% CI: 0.02-0.04), and the study rate was 0.017 (0.007) (95% CI: 0.01-0.02) (P < .0001). There was no difference in mortality rates across all cohorts.

CONCLUSIONS

Implementation of clinical decision-support alerts was associated with a decrease in RBCTs, which suggests improved adoption of evidence-based recommendations. This strategy might be widely applied to promote timely adoption of scientific evidence.

[Clinical impact of length of storage before red blood cell transfusion]

Presently, red blood cell units are stored up to 42 days in France and Canada. Length of storage of red blood cell units is not based on clinical outcomes: it is rather based on a decision made by some experts in the 1940s that red blood cell units can be stored as long as the average hemolysis is lower than 1% and the proportion of red blood cells still alive 24 hours post-transfusion is higher than 70%. Data reported recently suggest that transfusion with older red blood cell units may jeopardize the outcome of severely ill patients. In this paper, we comment the data already published on this question, and we summarize the randomized clinical trials presently on-going that were undertaken to address the relationship between length of storage of red blood cell units and outcomes of transfused patients.

Transfusion in the critically ill: does it affect outcome?

Anemia and red blood cell (RBC) transfusions are common in critically ill and injured, trauma, and surgical patients. Tolerance of anemia is highly variable, depending on the presence of cardiovascular and other comorbid diseases that may diminish the hemodynamic response to a lower hemoglobin (Hb) level. The quest to define a minimum threshold Hb concentration at which patients achieve significant benefit to improve outcome has not yet been identified. Complications related to RBC transfusion are related to RBC storage and intrinsic properties of donor allogeneic RBCs, including bacterial contamination, transfusion-related acute lung injury, and transfusion-related immunomodulation. The best evidence related to transfusion-related outcome involves titrating transfusion requirements to parameters of severity of illness rather than arbitrarily defined Hb levels.

Association between length of storage of transfused red blood cells and multiple organ dysfunction syndrome in pediatric intensive care patients

BACKGROUND

The objective was to determine if there is an association between red blood cell (RBC) storage time and development of new or progressive multiple organ dysfunction syndrome (MODS) in critically ill children.

STUDY DESIGN AND METHODS

This was an analytic cohort analysis of patients enrolled in a randomized controlled trial, TRIPICU (Transfusion Requirements in Pediatric Intensive Care Units; ISRCTN37246456), in which stable critically ill children were randomly assigned to a restrictive or liberal strategy. Transfused patients were analyzed using three different sliding time cutoffs (7, 14, and 21 days). Storage time for multiply transfused patients was defined according to the oldest unit transfused.

RESULTS

A total of 455 patients were retained (liberal, 310; restrictive, 145). Multivariate logistic regression was performed to determine independent associations. In the restrictive group, a maximum RBC storage time of more than 21 days was independently associated with new or progressive MODS (adjusted odds ratio [OR], 3.29; 95% confidence interval [CI], 1.21-9.04). The same association was found in the liberal group for a storage time of more than 14 days (adjusted OR, 2.50; 95% CI, 1.12-5.58). When the two groups were combined in a meta-analysis, a storage time of more than 14 days was independently associated with increased MODS (adjusted OR, 2.23; 95% CI, 1.20-4.15) and more than 21 days was associated with increased Pediatric Logistic Organ Dysfunction (PELOD) scores (adjusted mean difference, 4.26; 95% CI, 1.99-6.53) and higher mortality (9.2% vs. 3.8%).

CONCLUSION

Stable critically ill children who receive RBC units with storage times longer than 2 to 3 weeks may be at greater risk of developing new or progressive MODS.

Should fresh blood be recommended for intensive care patients?

Fresh blood has many potential advantages over older blood, but there is no evidence that these properties translate into clinical benefit for intensive care patients. The observational multicenter study by Karam and colleagues provides some evidence suggesting that blood stored for less than 14 days is better than older blood in terms of new organ failure and reduction in length of stay in pediatric intensive care units. Though in favor of using young blood, this study suffers from several limitations. As a consequence, it is ethical and certainly pertinent to conduct a randomized clinical trial in order to test the hypothesis that fresh blood might reduce mortality. The rationale is strong and the potential benefit of fresh blood is substantial.

Association between length of storage of red blood cell units and outcome of critically ill children: a prospective observational study

INTRODUCTION

Transfusion is a common treatment in pediatric intensive care units (PICUs). Studies in adults suggest that prolonged storage of red blood cell units is associated with worse clinical outcome. No prospective study has been conducted in children. Our objectives were to assess the clinical impact of the length of storage of red blood cell units on clinical outcome of critically ill children.

METHODS

Prospective, observational study conducted in 30 North American centers, in consecutive patients aged <18 years with a stay >or= 48 hours in a PICU. The primary outcome measure was the incidence of multiple organ dysfunction syndrome after transfusion. The secondary outcomes were 28-day mortality and PICU length of stay. Odds ratios were adjusted for gender, age, number of organ dysfunctions at admission, total number of transfusions, and total dose of transfusion, using a multiple logistic regression model.

RESULTS

The median length of storage was 14 days in 296 patients with documented length of storage. For patients receiving blood stored >or= 14 days, the adjusted odds ratio for an increased incidence of multiple organ dysfunction syndrome was 1.87 (95% CI 1.04;3.27, P = 0.03). There was also a significant difference in the total PICU length of stay (adjusted median difference +3.7 days, P < 0.001) and no significant change in mortality.

CONCLUSIONS

In critically ill children, transfusion of red blood cell units stored for >or= 14 days is independently associated with an increased occurrence of multiple organ dysfunction syndrome and prolonged PICU stay.

Association between length of storage of red blood cell units and outcome of critically ill children: a prospective observational study

INTRODUCTION

Transfusion is a common treatment in pediatric intensive care units (PICUs). Studies in adults suggest that prolonged storage of red blood cell units is associated with worse clinical outcome. No prospective study has been conducted in children. Our objectives were to assess the clinical impact of the length of storage of red blood cell units on clinical outcome of critically ill children.

METHODS

Prospective, observational study conducted in 30 North American centers, in consecutive patients aged <18 years with a stay >or= 48 hours in a PICU. The primary outcome measure was the incidence of multiple organ dysfunction syndrome after transfusion. The secondary outcomes were 28-day mortality and PICU length of stay. Odds ratios were adjusted for gender, age, number of organ dysfunctions at admission, total number of transfusions, and total dose of transfusion, using a multiple logistic regression model.

RESULTS

The median length of storage was 14 days in 296 patients with documented length of storage. For patients receiving blood stored >or= 14 days, the adjusted odds ratio for an increased incidence of multiple organ dysfunction syndrome was 1.87 (95% CI 1.04;3.27, P = 0.03). There was also a significant difference in the total PICU length of stay (adjusted median difference +3.7 days, P < 0.001) and no significant change in mortality.

CONCLUSIONS

In critically ill children, transfusion of red blood cell units stored for >or= 14 days is independently associated with an increased occurrence of multiple organ dysfunction syndrome and prolonged PICU stay.