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

Effect of red blood cell storage time in pediatric cardiac surgery patients: A subgroup analysis of a randomized controlled trial

Objective

This study aimed to determine whether or not transfusion of fresh red blood cells (RBCs) reduced the incidence of new or progressive multiple organ dysfunction syndrome compared with standard-issue RBCs in pediatric patients undergoing cardiac surgery.

Methods

Preplanned secondary analysis of the Age of Blood in Children in Pediatric Intensive Care Unit study, an international randomized controlled trial. This study included children enrolled in the Age of Blood in Children in Pediatric Intensive Care Unit trial and admitted to a pediatric intensive care unit after cardiac surgery with cardiopulmonary bypass. Patients were randomized to receive either fresh (stored ≤7 days) or standard-issue RBCs. The primary outcome measure was new or progressive multiple organ dysfunction syndrome, measured up to 28 days postrandomization or at pediatric intensive care unit discharge, or death.

Results

One hundred seventy-eight patients (median age, 0.6 years; interquartile range, 0.3-2.6 years) were included with 89 patients randomized to the fresh RBCs group (median length of storage, 5 days; interquartile range, 4-6 days) and 89 to the standard-issue RBCs group (median length of storage, 18 days; interquartile range, 13-22 days). There were no statistically significant differences in new or progressive multiple organ dysfunction syndrome between fresh (43 out of 89 [48.3%]) and standard-issue RBCs groups (38 out of 88 [43.2%]), with a relative risk of 1.12 (95% CI, 0.81 to 1.54; P = .49) and an unadjusted absolute risk difference of 5.1% (95% CI, -9.5% to 19.8%; P = .49).

Conclusions

In neonates and children undergoing cardiac surgery with cardiopulmonary bypass, the use of fresh RBCs did not reduce the incidence of new or progressive multiple organ dysfunction syndrome compared with the standard-issue RBCs. A larger trial is needed to confirm these results.

The estimated negative impacts on the red blood cell inventory of reducing shelf-life at two large health authorities in British Columbia, Canada, using a discrete-event simulation model

BACKGROUND AND OBJECTIVES

Reducing the maximum red blood cell (RBC) shelf-life is under consideration due to potential negative effects of older blood. An assessment of the impacts of this change on blood supply chain management is evaluated.

MATERIALS AND METHODS

We performed a simulation study using data from 2017 to 2018 to estimate the outdate rate (ODR), STAT order and non-group-specific RBC transfusion at two Canadian health authorities (HAs).

RESULTS

Shortening shelf-life from 42 to 35 and 28 days led to the following: ODRs (in percentage) in both HAs increased from 0.52% (95% confidence interval [CI] 0.50-0.54) to 1.32% (95% CI 1.26-1.38) and 5.47% (95% CI 5.34-5.60), respectively (p < 0.05). The estimated yearly median of outdated RBCs increased from 220 (interquartile range [IQR] 199-242) to 549 (IQR 530-576) and 2422 (IQR 2308-2470), respectively (p < 0.05). The median number of outdated redistributed units increased from 152 (IQR 136-168) to 356 (IQR 331-369) and 1644 (IQR 1591-1741), respectively (p < 0.05). The majority of outdated RBC units were from redistributed units rather than units ordered from the blood supplier. The estimated weekly mean STAT orders increased from 11.4 (95% CI 11.2-11.5) to 14.1 (95% CI 13.1-14.3) and 20.9 (95% CI 20.6-21.1), respectively (p < 0.001). The non-group-specific RBC transfusion rate increased from 4.7% (95% CI 4.6-4.8) to 8.1% (95% CI 7.9-8.3) and 15.6% (95% CI 15.3-16.4), respectively (p < 0.001). Changes in ordering schedules, decreased inventory levels and fresher blood received simulated minimally mitigated these impacts.

CONCLUSION

Decreasing RBC shelf-life negatively impacted RBC inventory management, including increasing RBC outdating and STAT orders, which supply modifications minimally mitigate.

Association Between Length of Storage of Transfused Packed RBC Units and Outcome of Surgical Critically Ill Adults: A Subgroup Analysis of the Age of Blood Evaluation Randomized Trial

OBJECTIVES

The Age of Blood Evaluation (ABLE) study reported no clinical benefit in fresher compared with standard delivery RBC units (length of storage: 6.9 ± 4.1 vs 22.0 ± 8.4 d, respectively). Perioperative patients are often anemic, at risk of blood loss, and more exposed to RBC transfusions. We address the question whether fresh RBC units are safer than standard delivery RBC units in perioperative ICU patients.

DESIGN

Subgroup analysis of surgical nontrauma adults enrolled in the ABLE randomized controlled trial.

SETTING

ICUs.

PATIENTS

Three hundred twenty surgical patients among the 2,510 ICU adults recruited in the ABLE study who had a request for a first RBC transfusion in the first week in ICU stay and an anticipated length of mechanical ventilation greater than or equal to 48 hours. We included perioperative patients but excluded elective cardiac surgery and trauma.

INTERVENTIONS

Surgical participants were allocated to receive either RBC units stored less than or equal to 7 days or standard issue RBC.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was 90-day all-cause mortality. One hundred seventy-two perioperative patients were allocated to the fresh and 148 to the standard group. Baseline data were similar. The length of storage was 7.2 ± 6.4 in fresh and 20.6 ± 8.4 days in standard group ( p < 0.0001). The 90-day mortality was 29.7% and 28.4%, respectively (absolute risk difference: 0.01; 95% CI -0.09 to 0.11; p = 0.803). No significant differences were observed for all secondary outcomes, including 6-month mortality, even after adjustment for age, country, and Acute Physiology and Chronic Health Evaluation score.

CONCLUSIONS

There was no evidence that fresh red cells improved outcomes as compared to standard issue red cells in critically ill surgical patients, consistent with other patients enrolled in the ABLE trial.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Hypothermic storage of leukoreduced red blood cells for greater than 21 days is a safe alternative to irradiation

BACKGROUND

Irradiation of red blood cells (RBCs) inactivates residual donor T lymphocytes to prevent transfusion-associated graft-vs-host disease (TA-GVHD) but can have adverse effects on recipients and inventory management. Reported incidence of TA-GVHD is lower when leukoreduced RBCs and older blood products are transfused; therefore, the impact of leukoreduction and storage was evaluated as an alternative prevention strategy.

STUDY DESIGN AND METHODS

Effectiveness of leukoreduction filters on white blood cell (WBC) proliferation was evaluated by filtering buffy coat (BC) products and isolating residual WBCs. Additionally, leukoreduced RBCs were spiked with 5 × 10⁶ WBCs on Day 21 of hypothermic storage, then stored and processed on Days 7, 14, and 21 to obtain residual WBCs to investigate the impact of hypothermic storage on their viability and proliferative ability. Viability of residual WBCs was assessed by staining with annexin V and an antibody cocktail for flow cytometry analysis. Proliferative ability was assessed by placing carboxyfluorescein diacetate succinimidyl ester-labeled residual WBCs into culture for 6 days with phytohemagglutinin before flow cytometry assessment.

RESULTS

Filtration of BC units depleted WBCs, particularly T lymphocytes, to 0.001% ± 0.003% cells/unit, although proliferative activity remained consistent with prefiltration levels of WBCs. WBCs in stored RBCs remained viable even on Day 21 of storage; however, the proliferative activity decreased to 0.24% ± 0.41%.

CONCLUSIONS

Hypothermic storage of RBCs for 21 days or more is sufficient to inactivate T lymphocytes, which may help prevent TA-GVHD when irradiated RBCs are not available.

Anemia Burden, Types and Associated Risk Factors among Kenyan Human Immunodeficiency Virus-1 and Mycobacterium Tuberculosis Co-infected Injection Substance Users

BACKGROUND

Although injection substance users and individuals co-infected with Human Immunodeficiency Virus-1 and Mycobacterium tuberculosis suffer marked hematologic derangements, the rates, levels, morphologic types and associated risk factors of anemia among Human immunodeficiency virus and Mycobacterium tuberculosis coinfected injection substance users has not been reported in Kenya.

METHODS

This cross-sectional study determined anemia rates, levels and morphologic types. Anemia was associated with clinical markers of disease- underweight, immunosuppression and viral load. Complete blood count, CD4 T-cell enumeration and viral load were determined via standard laboratory methods.

RESULTS

All injection substance users had higher rates of anaemia (HIV+TB+ ISUs, 79.3%; HIV-TB+ISUs, 70.0%; HIV+TB- ISUs, 56.6% and HIV-TB- ISUs, 56.2%) relative to non-ISUs (16.6%; P<0.05). A significant proportion of HIV+TB+ISUs (47.8%) developed severe anemia than other clinical groups. The commonest morphologic type of anemia in HIV+TB+ISUs was microcytic hypochromic (43.5%) followed by normocytic hypochromic (17.4%) relative to the other clinical groups. HIV+TB+ ISUs with CD4 T-cells <200/uL (OR: 2.94, 95% CI: 1.41-6.13, P=0.004) and CD4 Tcells of 200-349/uL (OR: 3.24, 95% CI: 1.66-6.31, P=0.001) associated with higher odds of developing anemia.

CONCLUSION

This study revealed that severe anemia and microcytic hypochromic anemia are the most common erythrocytic sequelae among Human Immunodeficiency Virus-1 and Mycobacterium tuberculosis co-infected ISUs. Those with CD4 T-cells < 350/uL are utmost expected to develop anemia.

Volume-dependent effect of stored red blood cells: A secondary analysis of the Age of Blood Evaluation trial

BACKGROUND

An increased risk of complications, including death, has been associated with stored red blood cell (RBC) units in observational studies but not in randomized trials. We aimed to evaluate for volume-dependent effects attributable to length of RBC storage in a secondary analysis of the Age of Blood Evaluation (ABLE) trial.

STUDY DESIGN AND METHODS

In the 2510 critically ill adults from the ABLE trial randomized to receive RBC units stored not more than 7 days or the oldest compatible RBC units, we estimated the hazard ratio (HR) for death by intensive care unit (ICU) and hospital discharge and by days 28, 90, and 180, within subgroups defined by the number of RBC units received. Extended Cox proportional hazards regression was used to model the HR.

RESULTS

A volume-dependent effect of storage age on survival was present for death by 90 and 180 days, but not earlier endpoints. The HR for death by 90 days was 0.55 (95% confidence interval [CI], 0.11-0.98, fresh vs standard) after transfusion of 6 RBC units but 1.45 (95% CI, 1.06-1.98) after transfusion of 1 RBC unit.

CONCLUSION

In this exploratory analysis, volume-dependent effects related to RBC storage were documented in the ABLE trial. The harms associated with small volumes of fresh RBC units and large volumes of older RBC units should be further explored.

Donor-dependent aging of young and old red blood cell subpopulations: Metabolic and functional heterogeneity

BACKGROUND

Characteristics of red blood cells (RBCs) are influenced by donor variability. This study assessed quality and metabolomic variables of RBC subpopulations of varied biologic age in red blood cell concentrates (RCCs) from male and female donors to evaluate their contribution to the storage lesion.

STUDY DESIGN AND METHODS

Red blood cell concentrates from healthy male (n = 6) and female (n = 4) donors were Percoll separated into less dense ("young", Y-RCCs) and dense ("old", O-RCCs) subpopulations, which were assessed weekly for 28 days for changes in hemolysis, mean cell volume (MCV), hemoglobin concentration (MCHC), hemoglobin autofluorescence (HGB), morphology index (MI), oxygen affinity (p50), rigidity, intracellular reactive oxygen species (ROS), calcium ([Ca²⁺ ]), and mass spectrometry-based metabolomics.

RESULTS

Young RCCs having disc-to-discoid morphology showed higher MCV and MI, but lower MCHC, HGB, and rigidity than O-RCCs, having discoid-to-spheroid shape. By Day 14, Y-RCCs retained lower hemolysis and rigidity and higher p50 compared to O-RCCs. Donor sex analyses indicated that females had higher MCV, HGB, ROS, and [Ca²⁺ ] and lower hemolysis than male RBCs, in addition to having a decreased rate of change in hemolysis by Day 28. Metabolic profiling indicated a significant sex-related signature across all groups with increased markers of high membrane lipid remodeling and antioxidant capacity in Y-RCCs, whereas O-RCCs had increased markers of oxidative stress and decreased coping capability.

CONCLUSION

The structural, functional, and metabolic dissimilarities of Y-RCCs and O-RCCs from female and male donors demonstrate RCC heterogeneity, where RBCs from females contribute less to the storage lesion and age slower than males.

Analysis of adult disease characteristics and mortality on MIMIC-III

Purpose

To deeply analyze the basic information and disease information of adult patients in the MIMIC-III (Medical Information Mart for Intensive Care III) database, and provide data reference for clinicians and researchers.

Materials and methods

Tableau2019.1.0 and Navicat12.0.29 were used for data analysis and extraction of disease distribution of adult patients in the MIMIC-III database.

Result

A total of 38,163 adult patients were included in the MIMIC-III database. Only 38,156 patients with the first diagnosis were selected. Among them, 21,598 were males accounting for 56.6% the median age was 66 years (Q1-Q3: 53–78), the median length of a hospital stay was 7 days (Q1-Q3: 4–12), and the median length of an ICU stay was 2.1 days (Q1-Q3: 1.2–4.1). Septicemia was the disease with the highest mortality rate among patients and the total mortality rate was 48.9%. The disease with the largest number of patients at the last time was other forms of chronic ischemic heart disease.

Conclusion

By analyzing the patients’ basic information, the admission spectrum and the disease morbidity and mortality can help more researchers understand the MIMIC-III database and facilitate further research.

Age of Red Cells for Transfusion and Outcomes in Critically Ill Patients: A Meta-Analysis

Objective

Whether the age of red blood cells (RBCs) affects mortality after transfusion in critically ill patients is controversial.

Methods

We searched MEDLINE, EMBASE, PubMed, Web of Science, and the Cochrane Library Central Register of Controlled Trials databases from inception to January 10, 2018 to identify systematic reviews or meta-analyses and published randomized controlled trials of the effects of fresh versus older blood transfusion on mortality of adults in the intensive care unit (ICU). There were no date restrictions, but the language was restricted to English. The primary outcome was mortality. Risk ratios (RR) and 95% confidence intervals (CI) were calculated.

Results

We included six trials that enrolled 8,467 critically ill patients and compared fresh RBC transfusion with current standard practice. There were no significant differences in 90-day mortality (RR 1.04, 95% CI 0.97, 1.12), 28/30-day mortality (RR 1.04, 95% CI 0.96, 1.13), in-hospital mortality (RR 1.06, 95% CI 0.94, 1.19), and in-ICU mortality (RR 1.11, 95% CI 0.97, 1.27) with fresh RBC transfusion compared with older blood transfusion.

Conclusions

The study concluded that age of red cells for transfusion did not affect the outcomes in critically ill patients.

Effect of age of transfused red blood cells on neurologic outcome following traumatic brain injury (ABLE-tbi Study): a nested study of the Age of Blood Evaluation (ABLE) trial

BACKGROUND

Anemia is common in critically ill patients with traumatic brain injury, and often requires red blood cell transfusion. Studies suggest that prolonged storage causes lesions of the red blood cells, including a decreased ability to carry oxygen. Considering the susceptibility of the brain to hypoxemia, victims of traumatic brain injury may thus be more vulnerable to exposure to older red blood cells.

METHODS

Our study aimed to ascertain whether the administration of fresh red blood cells (seven days or less) results in a better neurologic outcome compared with standard red blood cells in critically ill patients with traumatic brain injury requiring transfusion. The Age of Blood Evaluation in traumatic brain injury (ABLE-tbi) study was a nested study within the ABLE study (ISRCTN44878718). Our primary outcome was the extended Glasgow Outcome Scale (GOSe) at six months.

RESULTS

In the ABLE study, 217 subjects suffered a traumatic brain injury: 110 in the fresh group, and 107 in the standard group. In the fresh group, 68 (73.1%) of the patients had an unfavourable neurologic outcome (GOSe ≤ 4) compared with 60 (64.5%) in the standard group (P = 0.21). Using a sliding dichotomy approach, we observed no overall effect of fresh red blood cells on neurologic outcome (odds ratio [OR], 1.34; 95% confidence interval [CI], 0.72 to 2.50; P = 0.35) but observed differences across prognostic bands with a decreased odds of unfavourable outcome in patients with the best prognosis at baseline (OR, 0.33; 95% CI, 0.11 to 0.96; P = 0.04) but an increased odds in those with intermediate and worst baseline prognosis (OR, 5.88; 95% CI,1.66 to 20.81; P = 0.006; and OR, 1.67; 95% CI, 0.53 to 5.30; P = 0.38, respectively).

CONCLUSION

Overall, transfusion of fresh red blood cells was not associated with a better neurologic outcome at six months in critically ill patients with traumatic brain injury. Nevertheless, we cannot exclude a differential effect according to the patient baseline prognosis.

TRIAL REGISTRATION

ABLE study (ISRCTN44878718); registered 22 August, 2008.

Transfusion of red blood cells stored for shorter versus longer duration for all conditions

BACKGROUND

Red blood cell (RBC) transfusion is a common treatment for anaemia in many conditions. The safety and efficacy of transfusing RBC units that have been stored for different durations before a transfusion is a current concern. The duration of storage for a RBC unit can be up to 42 days. If evidence from randomised controlled trials (RCT) were to indicate that clinical outcomes are affected by storage duration, the implications for inventory management and clinical practice would be significant.

OBJECTIVES

To assess the effects of using red blood cells (RBCs) stored for a shorter versus a longer duration, or versus RBCs stored for standard practice duration, in people requiring a RBC transfusion.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, PubMed (for epublications), LILACS, Transfusion Evidence Library, Web of Science CPCI-S and four international clinical trial registries on 20 November 2017.

SELECTION CRITERIA

We included RCTs that compared transfusion of RBCs of shorter versus longer storage duration, or versus standard practice storage duration.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods.

MAIN RESULTS

We included 22 trials (42,835 participants) in this review.The GRADE quality of evidence ranged from very low to moderate for our primary outcome of in-hospital and short-term mortality reported at different time points.Transfusion of RBCs of shorter versus longer storage duration Eleven trials (2249 participants) compared transfusion of RBCs of shorter versus longer storage duration. Two trials enrolled low birth weight neonates, two enrolled children with severe anaemia secondary to malaria or sickle cell disease, and eight enrolled adults across a range of clinical settings (intensive care, cardiac surgery, major elective surgery, hospitalised in-patients, haematology outpatients). We judged only two trials to be at low risk of bias across all domains; most trials had an unclear risk for multiple domains.Transfusion of RBCs of shorter versus longer storage duration probably leads to little or no difference in mortality at seven-day follow-up (risk ratio (RR) 1.42, 95% confidence interval (CI) 0.66 to 3.06; 1 trial, 3098 participants; moderate quality evidence) or 30-day follow-up (RR 0.85, 95%CI 0.50 to 1.45; 2 trials, 1121 participants; moderate quality evidence) in adults undergoing major elective cardiac or non-cardiac surgery.For neonates, no studies reported on the primary outcome of in-hospital or short-term mortality. At 40 weeks gestational age, the effect of RBCs of shorter versus longer storage duration on the risk of death was uncertain, as the quality of evidence is very low (RR 0.90, 95% CI 0.41 to 1.85; 1 trial, 52 participants).The effect of RBCs of shorter versus longer storage duration on the risk of death in children with severe anaemia was also uncertain within 24 hours of transfusion (RR 1.50, 95% CI 0.43 to 5.25; 2 trials, 364 participants; very low quality evidence), or at 30-day follow-up (RR 1.40, 95% CI 0.45 to 4.31; 1 trial, 290 participants; low quality evidence).Only one trial, in children with severe anaemia (290 participants), reported adverse transfusion reactions. Only one child in each arm experienced an adverse reaction within 24 hours of transfusion.Transfusion of RBCs of shorter versus standard practice storage duration Eleven trials (40,588 participants) compared transfusion of RBCs of shorter versus standard practice storage duration. Three trials enrolled critically ill term neonates; two of these enrolled very low birth weight neonates. There were no trials in children. Eight trials enrolled critically ill and non-critically ill adults, with most being hospitalised. We judged four trials to be at low risk of bias across all domains with the others having an unclear risk of bias across multiple domains.Transfusion of RBCs of shorter versus standard practice storage duration probably leads to little or no difference in adult in-hospital mortality (RR 1.05, 95% CI 0.97 to 1.14; 4 trials, 25,704 participants; moderate quality evidence), ICU mortality (RR 1.06, 95% CI 0.98 to 1.15; 3 trials, 13,066 participants; moderate quality evidence), or 30-day mortality (RR 1.04, 95% CI 0.96 to 1.13; 4 trials, 7510 participants;moderate quality evidence).Two of the three trials that enrolled neonates reported that there were no adverse transfusion reactions. One trial reported an isolated case of cytomegalovirus infection in participants assigned to the standard practice storage duration group. Two trials in critically ill adults reported data on transfusion reactions: one observed no difference in acute transfusion reactions between arms (RR 0.67, 95% CI 0.19 to 2.36, 2413 participants), but the other observed more febrile nonhaemolytic reactions in the shorter storage duration arm (RR 1.48, 95% CI 1.13 to 1.95, 4919 participants).Trial sequential analysis showed that we may now have sufficient evidence to reject a 5% relative risk increase or decrease of death within 30 days when transfusing RBCs of shorter versus longer storage duration across all patient groups.

AUTHORS' CONCLUSIONS

The effect of storage duration on clinically important outcomes has now been investigated in large, high quality RCTs, predominantly in adults. There appears to be no evidence of an effect on mortality that is related to length of storage of transfused RBCs. However, the quality of evidence in neonates and children is low. The current practice in blood banks of using the oldest available RBCs can be continued safely. Additional RCTs are not required, but research using alternative study designs, should focus on particular subgroups (e.g. those requiring multiple RBC units) and on factors affecting RBC quality.

Impact of perioperative blood transfusion on gene expression biomarkers in patients with gastrointestinal cancer

OBJECTIVES

To explore the impacts of perioperative blood transfusion on specific pattern of inflammatory gene expression and nosocomial infections in gastrointestinal cancer patients.

METHODS

A total of 60 gastrointestinal cancer patients aged over 27 years were recruited, blood transfusion was administered to 30 patients. The peripheral venous blood was drawn from the 30 patients undergoing transfusions and messenger RNA (mRNA) was extracted from PAXGene tubes collected before surgery and at 48 h following the operation. T-helper cell subtype transcription factors were quantified using quantitative real-time polymerase chain reaction. These genes were selected based on their ability to represent specific immune pathways and their expression level of Th1, Th2 and Th17 and the major Treg-specific TFs T-bet, GATA-3, RORγt and FOXP3 were measured. Postoperative infections were documented using predefined criteria.

RESULTS

There were significantly lower in Th1-specific TF T-bet (P < 0.001) mRNA levels and significantly higher in Th2-specifc TF, GATA-3 (P < 0.001) mRNA levels assayed at 48 h. There was significantly lower in T-bet mRNA/GATA-3 (P < 0.001) mRNA ratio assayed at 48 h. There were significantly higher in Th17-specific TF RORγt (P < 0.001) and Treg-specific TF Foxp3 (P < 0.001) mRNA levels assayed at 48 h. Patients receiving a blood transfusion were more likely to develop postoperative infections (P = 0.02).

CONCLUSION

There is an association between an immunosuppressive pattern of gene expressions and blood transfusion. This gene expression profile includes a reduction in the activity of T helper cell type 1 (Th1) pathways in those patients receiving a blood transfusion. Furthermore, blood transfusion was associated with an increased susceptibility to nosocomial infections.

Rapid bedside rejuvenation of red blood cell with an autologous cell salvage device

BACKGROUND AND OBJECTIVES

During storage, red blood cells (RBCs) undergo physicochemical changes which affect the quality, function, and in vivo survival of transfused packed RBCs (pRBC). Changes include decreased 2,3-diphosphoglycerate (2,3-DPG) levels, decreased ATP, changes in mechanical properties and oxidative injury. RBC rejuvenation is a method used to increase levels of 2,3-DPG and ATP in pRBCs. This process requires incubating the pRBCs with a rejuvenation solution and subsequent washing. Standard blood bank protocols using the COBE 2991 Cell Processor require several hours of preparation. The objective of this study was to verify if a bedside protocol for rejuvenating pRBC and washing with the Sorin Xtra autologous cell salvage system could be used.

MATERIALS AND METHODS

Outdated pRBC units were obtained and rejuvenated in a model operating suite using a dry air incubator for 1 h at 37°C. Six units of pRBCs were pre-diluted with saline (1000 ml) and six units were not pre-diluted with saline. All units were washed with normal saline (1000 ml) using an apheresis-design cell salvage device in manual mode and wash volume set to 3000 ml. Samples were collected and analyzed for standard RBC quality parameters at baseline and post-wash.

RESULTS

Total pRBC wash efficiency was 94% ± 12% at a final hematocrit of 67.7 ± 5.9% while maintaining post-wash hemolysis 0.24 ± 0.12 %. Pre-dilution prior to washing did not confer statistically significant differences in final RBC quality parameters with the notable exceptions of calculated hemolysis and supernatant potassium levels (P < 0.05). The washing process can be completed within 10 min. The post-wash RBC parameters are appropriate for immediate transfusion to patients.

Transfusion of packed red blood cells at the end of shelf life is associated with increased risk of mortality - a pooled patient data analysis of 16 observational trials

Observational studies address packed red blood cell effects at the end of shelf life and have larger sample sizes compared to randomized control trials. Meta-analyses combining data from observational studies have been complicated by differences in aggregate transfused packed red blood cell age and outcome reporting. This study abrogated these issues by taking a pooled patient data approach. Observational studies reporting packed red blood cell age and clinical outcomes were identified and patient-level data sets were sought from investigators. Odds ratios and 95% confidence intervals for binary outcomes were calculated for each study, with mean packed red blood cell age or maximum packed red blood cell age acting as independent variables. The relationship between mean packed red blood cell age and hospital length of stay for each paper was analyzed using zero-inflated Poisson regression. Random effects models combined paper-level effect estimates. Extremes analyses were completed by comparing patients transfused with mean packed red blood cell aged less than ten days to those transfused with mean packed red blood cell aged at least 30 days. sixteen datasets were available for pooled patient data analysis. Mean packed red blood cell age of at least 30 days was associated with an increased risk of in-hospital mortality compared to mean packed red blood cell of less than ten days (odds ratio: 3.25, 95% confidence interval: 1.27–8.29). Packed red blood cell age was not correlated to increased risks of nosocomial infection or prolonged length of hospital stay.

Age of transfused blood in critically ill adult trauma patients: a prespecified nested analysis of the Age of Blood Evaluation randomized trial

BACKGROUND

Blood transfusion is common in the resuscitation of patients with traumatic injury. However, the clinical impact of the length of storage of transfused blood is unclear in this population.

STUDY DESIGN AND METHODS

We undertook a prespecified nested analysis of 372 trauma victims of the 2510 critically ill patients from 64 centers treated as part of the Age of Blood Evaluation (ABLE) randomized controlled trial. Patients were randomized according to their trauma status to receive either a transfusion of fresh blood stored not more than 7 days or standard-issue blood. Our primary outcome was 90-day all-cause mortality.

RESULTS

Overall, 186 trauma patients received fresh blood and 186 received standard-issue blood. Adherence to transfusion protocol was 94% (915/971) for all fresh blood transfused and 100% (753/753) for all standard-issue blood transfused. Mean ± SD blood storage duration was 5.6 ± 3.8 days in the fresh group and 22.7 ± 8.4 days in the standard-issue group (p < 0.001). Ninety-day mortality in the fresh group was 21% (38/185), compared to 16% (29/184) in the standard-issue group, with an unadjusted absolute risk difference of 5% (95% confidence interval [CI], -3.1 to 12.6) and an adjusted absolute risk difference of 2% (95% CI, -3.5 to 6.8).

CONCLUSION

In critically ill trauma patients, transfusion of fresh blood did not decrease 90-day mortality or secondary outcomes, a finding similar to the overall population of the ABLE trial.

A multicentre randomised controlled trial of Transfusion Indication Threshold Reduction on transfusion rates, morbidity and health-care resource use following cardiac surgery (TITRe2)

BACKGROUND

Uncertainty about optimal red blood cell transfusion thresholds in cardiac surgery is reflected in widely varying transfusion rates between surgeons and cardiac centres.

OBJECTIVE

To test the hypothesis that a restrictive compared with a liberal threshold for red blood cell transfusion after cardiac surgery reduces post-operative morbidity and health-care costs.

DESIGN

Multicentre, parallel randomised controlled trial and within-trial cost-utility analysis from a UK NHS and Personal Social Services perspective. We could not blind health-care staff but tried to blind participants. Random allocations were generated by computer and minimised by centre and operation.

SETTING

Seventeen specialist cardiac surgery centres in UK NHS hospitals.

PARTICIPANTS

Patients aged > 16 years undergoing non-emergency cardiac surgery with post-operative haemoglobin < 9 g/dl. Exclusion criteria were: unwilling to have transfusion owing to beliefs; platelet, red blood cell or clotting disorder; ongoing or recurrent sepsis; and critical limb ischaemia.

INTERVENTIONS

Participants in the liberal group were eligible for transfusion immediately after randomisation (post-operative haemoglobin < 9 g/dl); participants in the restrictive group were eligible for transfusion if their post-operative haemoglobin fell to < 7.5 g/dl during the index hospital stay.

MAIN OUTCOME MEASURES

The primary outcome was a composite outcome of any serious infectious (sepsis or wound infection) or ischaemic event (permanent stroke, myocardial infarction, gut infarction or acute kidney injury) during the 3 months after randomisation. Events were verified or adjudicated by blinded personnel. Secondary outcomes included blood products transfused; infectious events; ischaemic events; quality of life (European Quality of Life-5 Dimensions); duration of intensive care or high-dependency unit stay; duration of hospital stay; significant pulmonary morbidity; all-cause mortality; resource use, costs and cost-effectiveness.

RESULTS

We randomised 2007 participants between 15 July 2009 and 18 February 2013; four withdrew, leaving 1000 and 1003 in the restrictive and liberal groups, respectively. Transfusion rates after randomisation were 53.4% (534/1000) and 92.2% (925/1003). The primary outcome occurred in 35.1% (331/944) and 33.0% (317/962) of participants in the restrictive and liberal groups [odds ratio (OR) 1.11, 95% confidence interval (CI) 0.91 to 1.34; p = 0.30], respectively. There were no subgroup effects for the primary outcome, although some sensitivity analyses substantially altered the estimated OR. There were no differences for secondary clinical outcomes except for mortality, with more deaths in the restrictive group (4.2%, 42/1000 vs. 2.6%, 26/1003; hazard ratio 1.64, 95% CI 1.00 to 2.67; p = 0.045). Serious post-operative complications excluding primary outcome events occurred in 35.7% (354/991) and 34.2% (339/991) of participants in the restrictive and liberal groups, respectively. The total cost per participant from surgery to 3 months postoperatively differed little by group, just £182 less (standard error £488) in the restrictive group, largely owing to the difference in red blood cells cost. In the base-case cost-effectiveness results, the point estimate suggested that the restrictive threshold was cost-effective; however, this result was very uncertain partly owing to the negligible difference in quality-adjusted life-years gained.

CONCLUSIONS

A restrictive transfusion threshold is not superior to a liberal threshold after cardiac surgery. This finding supports restrictive transfusion due to reduced consumption and costs of red blood cells. However, secondary findings create uncertainty about recommending restrictive transfusion and prompt a new hypothesis that liberal transfusion may be superior after cardiac surgery. Reanalyses of existing trial datasets, excluding all participants who did not breach the liberal threshold, followed by a meta-analysis of the reanalysed results are the most obvious research steps to address the new hypothesis about the possible harm of red blood cell transfusion.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN70923932.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 60. See the NIHR Journals Library website for further project information.

The Age of BLood Evaluation (ABLE) randomised controlled trial: description of the UK-funded arm of the international trial, the UK cost-utility analysis and secondary analyses exploring factors associated with health-related quality of life and health-care costs during the 12-month follow-up

BACKGROUND

At present, red blood cells (RBCs) are stored for up to 42 days prior to transfusion. The relative effectiveness and safety of different RBC storage times prior to transfusion is uncertain.

OBJECTIVE

To assess the clinical effectiveness and cost-effectiveness of transfusing fresher RBCs (stored for ≤ 7 days) compared with current standard-aged RBCs in critically ill patients requiring blood transfusions.

DESIGN

The international Age of BLood Evaluation (ABLE) trial was a multicentre, randomised, blinded trial undertaken in Canada, the UK, the Netherlands and France. The UK trial was funded to contribute patients to the international trial and undertake a UK-specific health economic evaluation.

SETTING

Twenty intensive care units (ICUs) in the UK, as part of 64 international centres.

PARTICIPANTS

Critically ill patients aged ≥ 18 years (≥ 16 years in Scotland) expected to require mechanical ventilation for ≥ 48 hours and requiring a first RBC transfusion during the first 7 days in the ICU.

INTERVENTIONS

All decisions to transfuse RBCs were made by clinicians. One patient group received exclusively fresh RBCs stored for ≤ 7 days whenever transfusion was required from randomisation until hospital discharge. The other group received standard-issue RBCs throughout their hospital stay.

MAIN OUTCOME MEASURES

The primary outcome was 90-day mortality. Secondary outcomes included development of organ dysfunction, new thrombosis, infections and transfusion reactions. The primary economic evaluation was a cost-utility analysis.

RESULTS

The international trial took place between March 2009 and October 2014 (UK recruitment took place between January 2012 and October 2014). In total, 1211 patients were assigned to receive fresh blood and 1219 patients to receive standard-aged blood. RBCs were stored for a mean of 6.1 days [standard deviation (SD) ± 4.9 days] in the group allocated to receive fresh blood and 22.0 days (SD ± 8.4 days) in the group allocated to receive standard-aged blood. Patients received a mean of 4.3 RBC units (SD ± 5.2 RBC units) and 4.3 RBC units (SD ± 5.5 RBC units) in the groups receiving fresh blood and standard-aged blood, respectively. At 90 days, 37.0% of patients in the group allocated to receive fresh blood and 35.3% of patients in the group allocated to receive standard-aged blood had died {absolute risk difference 1.7% [95% confidence interval (CI) -2.1% to 5.5%]}. There were no between-group differences in any secondary outcomes. The UK cohort comprised 359 patients randomised and followed up for 12 months for the cost-utility analysis. UK patients had similar characteristics and outcomes to the international cohort. Mean total costs per patient were £32,346 (95% CI £29,306 to £35,385) in the group allocated to receive fresh blood and £33,353 (95% CI £29,729 to £36,978) in the group allocated to receive standard-aged blood. Approximately 85% of the total costs were incurred during the index hospital admission. There were no significant cost differences between the two groups [mean incremental costs for those receiving fresh vs. standard-aged blood: -£231 (95% CI -£4876 to £4415)], nor were there significant differences in outcomes (mean difference in quality-adjusted life-years -0.010, 95% CI -0.078 to 0.057).

LIMITATIONS

Adverse effects from the exclusive use of older RBCs compared with standard or fresh RBCs cannot be excluded.

CONCLUSIONS

The use of RBCs aged ≤ 7 days confers no clinical or economic benefit in critically ill patients compared with standard-aged RBCs.

FUTURE WORK

Future studies should address the safety of RBCs near the end of the current permitted storage age.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN44878718.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 62. See the NIHR Journals Library website for further project information. The international ABLE trial was also supported by peer-reviewed grants from the Canadian Institutes of Health Research (177453), Fonds de Recherche du Québec - Santé (24460), the French Ministry of Health Programme Hospitalier de Recherche Clinique (12.07, 2011) and by funding from Établissement Français du Sang and Sanquin Blood Supply.

"Blood failure" time to view blood as an organ: how oxygen debt contributes to blood failure and its implications for remote damage control resuscitation

Hemorrhagic shock is both a local and systemic disorder. In the context of systemic effects, blood loss may lead to levels of reduced oxygen delivery (DO2 ) sufficient to cause tissue ischemia. Similar to other physiologic debts such as sleep, it is not possible to incur a significant oxygen debt and suffer no consequences for lack of timely repayment. While the linkage between oxygen debt and traditional organ failure (renal, hepatic, lung, and circulation) has been long recognized, we should consider failure in two additional linked and very dynamic organ systems, the endothelium and blood. These systems are very sensitive to oxygen debt and at risk for failing, having further implications on all other organ systems. The degree of damage to the endothelium is largely modulated by the degree of oxygen debt. Thus hypoperfusion is believed to begin a cascade of events leading to acute traumatic coagulopathy (ATC). This combination of oxygen debt driven endothelial damage and ATC might be considered collectively as "blood failure" due to the highly connected networks between these drivers. This article presents the implications of oxygen debt for remote damage control resuscitation strategies, such as permissive hypotension and hemostatic resuscitation. We review the impact of whole blood resuscitation and red blood cell efficacy in mitigation of oxygen debt. At last, this article recognizes the need for simple and durable, lightweight equipment that can detect the adequacy of tissue DO2 and thus patient needs for resuscitative care. Point-of-care lactate measuring may be a predictive tool for identifying high-risk trauma patients and occult shock because it provides information beyond that of vital signs and mechanism of injury as it may help predict the level of oxygen debt accumulation and need for resuscitation. Serial measurements may also be valuable as a tool in guiding resuscitative efforts.

Red blood cell storage time and transfusion: current practice, concerns and future perspectives

Red blood cells (RBCs) units are the most requested transfusion product worldwide. Indications for transfusion include symptomatic anaemia, acute sickle cell crisis, and acute blood loss of more than 30% of the blood volume, with the aim of restoring tissue oxygen delivery. However, stored RBCs from donors are not a qualitative equal product, and, in many ways, this is a matter of concern in the transfusion practice. Besides donor-to-donor variation, the storage time influences the RBC unit at the qualitative level, as RBCs age in the storage bag and are exposed to the so-called storage lesion. Several studies have shown that the storage lesion leads to post-transfusion enhanced clearance, plasma transferrin saturation, nitric oxide scavenging and/or immunomodulation with potential unwanted transfusion-related clinical outcomes, such as acute lung injury or higher mortality rate. While, to date, several studies have claimed the risk or deleterious effects of "old" vs "young" RBC transfusion regimes, it is still a matter of debate, and consideration should be taken of the clinical context. Transfusion-dependent patients may benefit from transfusion with "young" RBC units, as it assures longer inter-transfusion periods, while transfusion with "old" RBC units is not itself harmful. Unbiased Omics approaches are being applied to the characterisation of RBC through storage, to better understand the (patho)physiological role of microparticles (MPs) that are found naturally, and also on stored RBC units. Perhaps RBC storage time is not an accurate surrogate for RBC quality and there is a need to establish which parameters do indeed reflect optimal efficacy and safety. A better Omics characterisation of components of "young" and "old" RBC units, including MPs, donor and recipient, might lead to the development of new therapies, including the use of engineered RBCs or MPs as cell-based drug delivering tools, or cost-effective personalised transfusion strategies.

Cryopreserved packed red blood cells in surgical patients: past, present, and future

Since the advent of anticoagulation and component storage of human blood products, allogeneic red blood cell transfusion has been one of the most common practices in modern medicine. Efforts to reduce the biochemical effects of storage, collectively known as the red blood cell storage lesion, and prolong the storage duration have led to numerous advancements in erythrocyte storage solutions. Cryopreservation and frozen storage of red blood cells in glycerol have been successfully utilised by many civilian and military institutions worldwide. Through progressive improvements in liquid storage of erythrocytes in novel storage solutions, the logistical need for cryopreserved red blood cells in the civilian setting has diminished. A growing body of current literature is focused on the clinical consequences of packed red blood cell age. Modern cryopreservation techniques show promise as a cost-effective method to ameliorate the negative effect of the red blood cell storage lesion, while meeting the technical and logistical needs of both civilian and military medicine. This review outlines the history of red blood cell cryopreservation, the clinical impact of red cell storage, and highlights the current literature on frozen blood and its impact on modern transfusion.

Iron metabolism following intravenous transfusion with stored versus fresh autologous erythrocyte concentrate in healthy dogs

OBJECTIVE To determine effects of IV transfusion with fresh (3-day-old) or stored (35-day-old) autologous erythrocyte concentrate on serum labile iron concentration, iron-binding capacity, and protein interaction with iron in dogs. ANIMALS 10 random-source healthy dogs. PROCEDURES Dogs were randomly assigned to receive autologous erythrocyte concentrate stored for 3 days (n = 5) or 35 days (5). One unit of whole blood was collected from each dog, and erythrocyte concentrates were prepared and stored as assigned. After erythrocyte storage, IV transfusion was performed, with dogs receiving their own erythrocyte concentrate. Blood samples were collected from each dog before and 5, 9, 24, 48, and 72 hours after transfusion. Serum was harvested for measurement of total iron, labile iron, transferrin, ferritin, hemoglobin, and haptoglobin concentrations. RESULTS For dogs that received fresh erythrocytes, serum concentrations of the various analytes largely remained unchanged after transfusion. For dogs that received stored erythrocytes, serum concentrations of total iron, labile iron, hemoglobin, and ferritin increased markedly and serum concentrations of transferrin and haptoglobin decreased after transfusion. CONCLUSIONS AND CLINICAL RELEVANCE Transfusion with autologous erythrocyte concentrate stored for 35 days resulted in evidence of intravascular hemolysis in healthy dogs. The associated marked increases in circulating concentrations of free iron and hemoglobin have the potential to adversely affect transfusion recipients.

A Comparative Study of the Effect of Leukoreduction and Pre-storage Leukodepletion on Red Blood Cells during Storage

Blood transfusion is a fundamental therapy in numerous pathological conditions. Regrettably, many clinical reports describe adverse transfusion's drawbacks due to red blood cells alterations during storage. Thus, the possibility for a blood bank to ameliorate the quality of the erythrocyte concentrates units is crucial to improve clinical results and reduce transfusion adverse occurrences. Leukodepletion is a pre-storage treatment recognized to better preserve the quality of red blood cells with respect to leukoreduction. Aim of this work is to unravel the biochemical and biophysical basis that sustain the good clinical outcomes associated to the use of leukodepleted erythrocytes units. Erythrocytes concentrates were prepared as leukoreduced (n = 8) and pre-storage leukodepleted (n = 8) and then studied during 6 weeks in blood bank conditions. Overall, the data indicate that leukodepletion not only provide red blood cells with an appropriate amount of nutrients for a longer time but also selects red blood cells characterized by a more resilient plasma membrane fit to prolong their viability. We believe these results will stimulate new ideas to further optimize the current storage protocols.

Perioperative Red Blood Cell Transfusion: What We Do Not Know

Objective:

Blood transfusion saves lives but may also increase the risk of injury. The objective of this review was to evaluate the possible adverse effects related to transfusion of red blood cell (RBC) concentrates stored for prolonged periods.

Data Sources:

The data used in this review were mainly from PubMed articles published in English up to February 2015.

Study Selection:

Clinical and basic research articles were selected according to their relevance to this topic.

Results:

The ex vivo changes to RBC that occur during storage are collectively called storage lesion. It is still inconclusive if transfusion of RBC with storage lesion has clinical relevance. Multiple ongoing prospective randomized controlled trials are aimed to clarify this clinical issue. It was observed that the adverse events related to stored RBC transfusion were prominent in certain patient populations, including trauma, critical care, pediatric, and cardiac surgery patients, which leads to the investigation of underlying mechanisms. It is demonstrated that free hemoglobin toxicity, decreasing of nitric oxide bioavailability, and free iron-induced increasing of inflammation may play an important role in this process.

Conclusion:

It is still unclear whether transfusion of older RBC has adverse effects, and if so, which factors determine such clinical effects. However, considering the magnitude of transfusion and the widespread medical significance, potential preventive strategies should be considered, especially for the susceptible recipients.

Effects of Aged Stored Autologous Red Blood Cells on Human Endothelial Function

RATIONALE

A major abnormality that characterizes the red cell "storage lesion" is increased hemolysis and reduced red cell lifespan after infusion. Low levels of intravascular hemolysis after transfusion of aged stored red cells disrupt nitric oxide (NO) bioavailabity, via accelerated NO scavenging reaction with cell-free plasma hemoglobin. The degree of intravascular hemolysis post-transfusion and effects on endothelial-dependent vasodilation responses to acetylcholine have not been fully characterized in humans.

OBJECTIVES

To evaluate the effects of blood aged to the limits of Food and Drug Administration-approved storage time on the human microcirculation and endothelial function.

METHODS

Eighteen healthy individuals donated 1 U of leukopheresed red cells, divided and autologously transfused into the forearm brachial artery 5 and 42 days after blood donation. Blood samples were obtained from stored blood bag supernatants and the antecubital vein of the infusion arm. Forearm blood flow measurements were performed using strain-gauge plethysmography during transfusion, followed by testing of endothelium-dependent blood flow with increasing doses of intraarterial acetylcholine.

MEASUREMENTS AND MAIN RESULTS

We demonstrate that aged stored blood has higher levels of arginase-1 and cell-free plasma hemoglobin. Compared with 5-day blood, the transfusion of 42-day packed red cells decreases acetylcholine-dependent forearm blood flows. Intravascular venous levels of arginase-1 and cell-free plasma hemoglobin increase immediately after red cell transfusion, with more significant increases observed after infusion of 42-day-old blood.

CONCLUSIONS

We demonstrate that the transfusion of blood at the limits of Food and Drug Administration-approved storage has a significant effect on the forearm circulation and impairs endothelial function. Clinical trial registered with www.clinicaltrials.gov (NCT 01137656).

Identified metabolic signature for assessing red blood cell unit quality is associated with endothelial damage markers and clinical outcomes

BACKGROUND

There has been interest in determining whether older red blood cell (RBC) units have negative clinical effects. Numerous observational studies have shown that older RBC units are an independent factor for patient mortality. However, recently published randomized clinical trials have shown no difference of clinical outcome for patients receiving old or fresh RBCs. An overlooked but essential issue in assessing RBC unit quality and ultimately designing the necessary clinical trials is a metric for what constitutes an old or fresh RBC unit.

STUDY DESIGN AND METHODS

Twenty RBC units were profiled using quantitative metabolomics over 42 days of storage in SAGM with 3- to 4-day time intervals. Metabolic pathway usage during storage was assessed using systems biology methods. The detected time intervals of the metabolic states were compared to clinical outcomes.

RESULTS

Using multivariate statistics, we identified a nonlinear decay process exhibiting three distinct metabolic states (Days 0-10, 10-17, and 17-42). Hematologic variables traditionally measured in the transfusion setting (e.g., pH, hemolysis, RBC indices) did not distinguish these three states. Systemic changes in pathway usage occurred between the three states, with key pathways changing in both magnitude and direction. Finally, an association was found between the time periods of the metabolic states with the clinical outcomes of more than 280,000 patients in the country of Denmark transfused over the past 15 years and endothelial damage markers in healthy volunteers undergoing autologous transfusions.

CONCLUSION

The state of RBC metabolism may be a better indicator of cellular quality than traditional hematologic variables.

Impact of the age of stored blood on trauma patient mortality: a systematic review

BACKGROUND

The impact of the age of stored red blood cells on mortality in patients sustaining traumatic injuries requiring transfusion of blood products is unknown. The objective of this systematic review was to identify and describe the available literature on the use of older versus newer blood in trauma patient populations.

METHODS

We searched PubMed, Embase, Lilac and the Cochrane Database for published studies comparing the transfusion of newer versus older red blood cells in adult patients sustaining traumatic injuries. Studies included for review reported on trauma patients receiving transfusions of packed red blood cells, identified the age of stored blood that was transfused and reported patient mortality as an end point. We extracted data using a standardized form and assessed study quality using the Newcastle-Ottawa Scale.

RESULTS

Seven studies were identified (6780 patients) from 3936 initial search results. Four studies reported that transfusion of older blood was independently associated with increased mortality in trauma patients, while 3 studies did not observe any increase in patient mortality with the use of older versus newer blood. Three studies associated the transfusion of older blood with adverse patient outcomes, including longer stay in the intensive care unit, complicated sepsis, pneumonia and renal dysfunction. Studies varied considerably in design, volumes of blood transfused and definitions applied for old and new blood..

CONCLUSION

The impact of the age of stored packed red blood cells on mortality in trauma patients is inconclusive. Future investigations are warranted.

Techniques to improve detection and analysis of extracellular vesicles using flow cytometry

Extracellular vesicles (EVs) range in size from 50 nm to 1 µm. Flow cytometry (FCM) is the most commonly used method for analyzing EVs; however, accurate characterization of EVs remains challenging due to their small size and lack of discrete positive populations. Here we report the use of optimization techniques that are especially well-suited for analyzing EVs from a high volume of clinical samples. Utilizing a two pronged approach that included 1) pre-filtration of antibodies to remove aggregates, followed by 2) detergent lysis of a replicate sample to account for remaining false positive events, we were able to effectively limit false positive non-EV events. In addition, we show that lysed samples are a useful alternative to isotypes for setting gates to exclude background fluorescence. To reduce background, we developed an approach using filters to "wash" samples post-staining thus providing a faster alternative to ultracentrifugation and sucrose gradient fractionation. In conclusion, use of these optimized techniques enhances the accuracy and efficiency of EV detection using FCM.

[Blood transfusion and inflammation as of yesterday, today and tomorrow]

Blood transfusion is made possible principally by use of donated homologous components that - in turn - can be perceived as sources of danger by recipients. This may create an innate immune response dominated by inflammation, especially when transfusion is repeated. Residual leukocytes in blood components can source inflammatory lesions but considerably less than used to be prior to systematic, early and stringent - in process - leukoreduction. Every blood component can cause inflammation, though barely in the case of therapeutic plasma (in such a case, this is mainly restricted to allergy). Iron that may be freed by red blood cells but also processing and storage lesions such as the emission of microparticles can reveal themselves as pro-inflammatory. Platelets in platelet components represent the main source of inflammatory and/or allergic hazards in transfusion; this is linked with processing and storage lesions but also with the platelet physiology itself. It is of utmost importance to avoid inflammatory adverse events in patients that are fragile because of their primary condition and/or treatment; this stands for their safety, as inflammation can be extremely severe and even lethal, and also for their comfort; this increases efficacy of transfusion programs while reducing the overall costs.

Relationship between hemoglobin concentration and extracorporeal blood flow as determinants of oxygen delivery during venovenous extracorporeal membrane oxygenation: a mathematical model

During veno-venous extracorporeal membrane oxygenation (VV-ECMO) support, optimization of oxygenation can be achieved by therapeutic interventions on both patient physiological variables and adjustment of ECMO settings. Based on the physiology of oxygen delivery during VV-ECMO support, we established the mathematical relationship between the variables which define the oxygenation state: hemoglobin (Hb), extracorporeal blood flow (ECBF), cardiac output (Q), and systemic oxygen consumption (VO2). Assuming constant values for Q and VO2, the model was applied to elucidate the interplay between Hb and ECBF in determining arterial oxygen saturation (SaO2), and the resultant systemic oxygen delivery (DO2) and native venous oxygen saturation (SvO2) in static conditions. At constant VO2 and Q, an inverse relationship exists between Hb and ECBF in determining SaO2 and SvO2. Despite the same value of SaO2, the DO2 resulting from the different combinations of Hb and ECBF progressively decreases with decreasing Hb. By demonstrating the quantitative relationship between Hb and ECBF as determinants of oxygenation during VV-ECMO support, this mathematical model could provide a theoretical basis for a rational approach to strategies to optimize oxygenation in patients on VV-ECMO.

Prolonged storage of packed red blood cells for blood transfusion

BACKGROUND

A blood transfusion is an acute intervention, used to address life- and health-threatening conditions on a short-term basis. Packed red blood cells are most often used for blood transfusion. Sometimes blood is transfused after prolonged storage but there is continuing debate as to whether transfusion of 'older' blood is as beneficial as transfusion of 'fresher' blood.

OBJECTIVES

To assess the clinical benefits and harms of prolonged storage of packed red blood cells, in comparison with fresh, on recipients of blood transfusion.

SEARCH METHODS

We ran the search on 1st May 2014. We searched the Cochrane Injuries Group Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), Embase (OvidSP), CINAHL (EBSCO Host) and two other databases. We also searched clinical trials registers and screened reference lists of the retrieved publications and reviews. We updated this search in June 2015 but these results have not yet been incorporated.

SELECTION CRITERIA

Randomised clinical trials including participants assessed as requiring red blood cell transfusion were eligible for inclusion. Prolonged storage was defined as red blood cells stored for ≥ 21 days in a blood bank. We did not apply limits regarding the duration of follow-up, or country where the study took place. We excluded trials where patients received a combination of short- and long-stored blood products, and also trials without a clear definition of prolonged storage.

DATA COLLECTION AND ANALYSIS

We independently performed study selection, risk of bias assessment and data extraction by at least two review authors. The major outcomes were death from any cause, transfusion-related acute lung injury, and adverse events. We estimated relative risk for dichotomous outcomes. We measured statistical heterogeneity using I(2). We used a random-effects model to synthesise the findings.

MAIN RESULTS

We identified three randomised clinical trials, involving a total of 120 participants, comparing packed red blood cells with ≥ 21 days storage ('prolonged' or 'older') versus packed red blood cells with < 21 days storage ('fresh'). We pooled data to assess the effect of prolonged storage on death from any cause. The confidence in the results from these trials was very low, due to the bias in their design and their limited sample sizes.The estimated effect of packed red blood cells with ≥ 21 days storage versus packed red blood cells with < 21 days storage for the outcome death from any cause was imprecise (5/45 [11.11%] versus 2/46 [4.34%]; RR 2.36; 95% CI 0.65 to 8.52; I(2): 0%, P = 0.26, very low quality of evidence). Trial sequential analysis, with only two trials, shows that we do not yet have convincing evidence that older packed red blood cells induce a 20% relative risk reduction of death from any cause compared with fresher packed red blood cells. No trial included other outcomes of interest specified in this review, namely transfusion-related acute lung injury, postoperative infections, and adverse events. The safety profile is unknown.

AUTHORS' CONCLUSIONS

Recognising the limitations of the review, relating to the size and nature of the included trials, this Cochrane Review provides no evidence to support or reject the use of packed red blood cells for blood transfusion which have been stored for ≥ 21 days ('prolonged' or 'older') compared with those stored for < 21 days ('fresh'). These results are based on three small single centre trials with high risks of bias. There is insufficient evidence to determine the effects of fresh or older packed red blood cells for blood transfusion. Therefore, we urge readers to interpret the trial results with caution. The results from four large ongoing trials will help to inform future updates of this review.

[The ABLE study: A randomized controlled trial on the efficacy of fresh red cell units to improve the outcome of transfused critically ill adults]

Red blood cell units are stored up to 42 days post-collection. The standard policy of blood banks is to deliver the oldest units in order to limit blood wastage. Many caregivers believe that giving fresh rather than old units can improve the outcome of their transfused patients. The ABLE study aims to check if the transfusion of red blood cell units stored seven days or less (fresh arm) improve the outcome of transfused critically ill adults compared to patients who received units delivered according to the standard delivery policy (control arm). From March 2009 to May 2014, 1211 patients were allocated to the fresh arm, 1219 to the control arm (length of storage: 6.1 ± 4.9 and 22.0 ± 8.4 days respectively, P<0.001). The primary outcome measure was 90-day all-cause mortality post-randomisation: there were 448 deaths (37.0%) in the fresh arm and 430 (35.3%) in the control arm (absolute risk difference: 1.7%; 95% confidence interval: -2.1% to 5.5%). In a survival analysis, the risk of death was higher in the fresh arm (hazard ratio: 1.1; 95%CI: 0.9 to 1.2), but the difference was not statistically significant (P=0.38). The same trend against the fresh arm was observed with all but one secondary outcome measures. The conclusion is that the transfusion of red blood cell units stored seven days or less does not improve the outcome of critically ill adults compared to the transfusion of units stored about three weeks (22.0 ± 8.4 days).

The influence of the storage lesion(s) on pediatric red cell transfusion

PURPOSE OF REVIEW

This article will analyze and evaluate the current evidence regarding the use of older, longer-stored red blood cells (RBCs) for transfusion in pediatric patients and will examine some of the postulated mechanisms of injury related to prolonged refrigerated storage of RBCs and studies reporting clinical outcomes.

RECENT FINDINGS

Three randomized controlled trials and seven observational studies have been conducted entirely in pediatric patients. The outcomes, mortality and morbidity in critically ill patients and children undergoing cardiac surgery, and necrotizing enterocolitis in premature infants, have been inconsistent. However, many of these studies have been confounded by study design, mixed patient populations, red cell preparation, and other factors.

SUMMARY

Further exploration into the possible deleterious effects of older, longer-stored RBC transfusions on mortality and morbidity in different pediatric populations is merited. Understanding the potential mechanisms of injury should help explain the clinical findings.

Transfusion of fresher versus older red blood cells for all conditions

BACKGROUND

Red blood cell transfusion is a common treatment for anaemia in many clinical conditions. One current concern is uncertainty as to the clinical consequences (notably efficacy and safety) of transfusing red blood cell units that have been stored for different durations of time before a transfusion. If evidence from randomised controlled trials were to indicate that clinical outcomes are affected by storage age, the implications for inventory management and clinical practice would be significant.

OBJECTIVES

To assess the effects of using fresher versus older red blood cells in people requiring a red blood cell transfusion.

SEARCH METHODS

We ran the search on 29th September 2014. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OvidSP), Embase (OvidSP), CINAHL (EBSCO), PubMed (for e-publications), three other databases and trial registers.

SELECTION CRITERIA

We included randomised controlled trials comparing fresher red blood cell transfusion versus active transfusion of older red blood cells, and comparing fresher red blood cell transfusion versus current standard practice. All definitions of 'fresher' and 'older'/'standard practice' red blood cells were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted from the trial report data on adverse red blood cell transfusion reactions, when reported.

MAIN RESULTS

We included 16 trials (1864 participants) in the review. Eight trials (279 participants) compared transfusion of fresher red blood cells versus transfusion of older stored red blood cells ('fresher' vs 'older'). Eight trials (1585 participants) compared the transfusion of fresher red blood cells versus current standard practice ('fresher' vs 'standard practice'). Five trials enrolled neonates, one trial enrolled children and 12 trials enrolled adults. Overall sample sizes were small: only two trials randomly assigned more than 100 participants.We performed no meta-analyses for a variety of reasons: no uniform definition of 'fresher' or 'older' red blood cell storage; overlap in the distribution of the age of red blood cells; and heterogeneity in measurements and reporting of outcomes of interest to this review. We tabulated and reported results by individual trial. Overall risk of bias was low or unclear, with four incidences of high risk of bias: in allocation concealment (three trials) and in incomplete outcome data (one trial).No trial measured all of the outcomes of interest in this review. Four trials comparing 'fresher' with 'older' red blood cells reported the primary outcome: mortality within seven days (one study; 74 participants) and at 30 days (three trials; 62 participants). Six trials comparing 'fresher' with 'standard practice' red blood cells reported the primary outcome: mortality within seven days (three studies; 159 participants) and at 30 days (three trials; 1018 participants). All 10 trials reported no clear differences in mortality at either time point between intervention arms.Three trials comparing 'fresher' with 'standard practice' red blood cells reported red blood cell transfusion-associated adverse events. No adverse reactions were reported in two trials, and one incidence of cytomegalovirus (CMV) infection was described in the 'standard practice' arm in one trial.Overall the trials reported no clear difference between either of the intervention comparisons in long-term mortality (three trials; 478 participants); clinically accepted measures of multiple organ dysfunction (two trials: 399 participants); incidence of in-hospital infection (two trials; 429 participants); duration of mechanical ventilation (three trials: 95 participants); and number of participants requiring respiratory organ support (five trials; 528 participants) or renal support (one trial; 57 participants). The outcome 'physiological markers of oxygen consumption or alterations in microcirculation' was reported by 11 studies, but the measures used were highly varied, and no formal statistical analysis was undertaken.

AUTHORS' CONCLUSIONS

Several factors precluded firm conclusions about the clinical outcomes of transfusing red blood cell units that have been stored for different periods of time before transfusion, including differences in clinical population and setting, diversity in the interventions used, methodological limitations and differences in how outcomes were measured and reported.No clear differences in the primary outcome - death - were noted between 'fresher' and 'older' or 'standard practice' red blood cells in trials that reported this outcome. Findings of a large number of ongoing trials will be incorporated into this review when they are published.Updates of this review will explore the degree of overlap in trials between 'fresher', 'older' and 'standard practice' storage ages of red blood cells and will consider whether the size of any observed effects is dependent on recipient factors such as clinical background, patient age or clinical presentation.

Changes in gene expression following trauma are related to the age of transfused packed red blood cells

BACKGROUND

Transfusion of packed red blood cells (PRBCs) is associated with an increased incidence of nosocomial infections and an increased risk of death. The duration of storage before transfusion may influence these outcomes. Here, we explore the association between the age of transfused PRBCs and specific patterns of inflammatory gene expression in severely injured trauma patients.

METHODS

Severely injured trauma patients requiring intensive care unit treatment and receiving transfusion of PRBCs within 24 hours of the injury were recruited. Blood samples were obtained within 2 hours of the trauma, at 24 hours, and at 72 hours. Messenger RNA was extracted from whole blood, and gene expression was quantified using quantitative polymerase chain reaction. The median age of the units of PRBCs transfused to each patient was recorded. The primary outcome measure was the change in candidate gene expression over the initial 72 hours.

RESULTS

Sixty-four patients were studied. Fifty-three patients (83%) were male, and the median age was 40.5 years (interquartile range [IQR], 31-59). Median Injury Severity Score (ISS) was 31.5 (IQR, 23-43), and 55 patients (86%) experienced a blunt injury. Forty-one patients (64%) developed a nosocomial infection, and 15 patients (23%) died before hospital discharge. Each patient received a median of 5 U of PRBCs (IQR, 4-9.8 U) during the first 24 hours of hospital admission. The median age of the units of PRBCs transfused in each patient was 20 days (IQR, 17-22 days). Older blood was associated with greater decreases in interleukin 12 (IL-12), IL-23, and RORγt (all p's < 0.05) gene expression over the initial 24 hours, greater decreases in IL-12 gene expression over 72 hours, and a rise in transforming growth factor β gene expression over the first 72 hours. A multivariate analysis confirmed the independence of these associations.

CONCLUSION

Increasing the duration of storage of PRBCs before transfusion is associated with a pattern of gene expression consistent with more severe immunosuppression.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

A systematic review of transfusion-associated graft-versus-host disease

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare complication of blood transfusion. The clinicolaboratory features of TA-GVHD and the relative contributions of recipient and component factors remain poorly understood. We conducted a systematic review of TA-GVHD reports. The HLA relationship between donor and recipient was classified as D = 0 when no donor antigens were foreign to the recipient vs D ≥ 1 when ≥1 donor antigen disparity occurred. We identified 348 unique cases. Criteria for component irradiation were met in 48.9% of cases (34.5% immune-compromised, 14.4% related-donor), although nonirradiated components were transfused in the vast majority of these (97.6%). Components were typically whole blood and red cells. When reported, component storage duration was ≤10 days in 94%, and 23 (6.6%) were leukoreduced (10 bedside, 2 prestorage, and 11 unknown). Among 84 cases with HLA data available, the category of D = 0 was present in 60 patients (71%) at either HLA class I or II loci and was more common among recipients without traditional indications for component irradiation. These data challenge the historic emphasis on host immune defects in the pathogenesis of TA-GVHD. The dominant mechanism of TA-GVHD in both immunocompetent and compromised hosts is exposure to viable donor lymphocytes not recognized as foreign by, but able to respond against, the recipient.

Effects of red-cell storage duration on patients undergoing cardiac surgery

BACKGROUND

Some observational studies have reported that transfusion of red-cell units that have been stored for more than 2 to 3 weeks is associated with serious, even fatal, adverse events. Patients undergoing cardiac surgery may be especially vulnerable to the adverse effects of transfusion.

METHODS

We conducted a randomized trial at multiple sites from 2010 to 2014. Participants 12 years of age or older who were undergoing complex cardiac surgery and were likely to undergo transfusion of red cells were randomly assigned to receive leukocyte-reduced red cells stored for 10 days or less (shorter-term storage group) or for 21 days or more (longer-term storage group) for all intraoperative and postoperative transfusions. The primary outcome was the change in Multiple Organ Dysfunction Score (MODS; range, 0 to 24, with higher scores indicating more severe organ dysfunction) from the preoperative score to the highest composite score through day 7 or the time of death or discharge.

RESULTS

The median storage time of red-cell units provided to the 1098 participants who received red-cell transfusion was 7 days in the shorter-term storage group and 28 days in the longer-term storage group. The mean change in MODS was an increase of 8.5 and 8.7 points, respectively (95% confidence interval for the difference, -0.6 to 0.3; P=0.44). The 7-day mortality was 2.8% in the shorter-term storage group and 2.0% in the longer-term storage group (P=0.43); 28-day mortality was 4.4% and 5.3%, respectively (P=0.57). Adverse events did not differ significantly between groups except that hyperbilirubinemia was more common in the longer-term storage group.

CONCLUSIONS

The duration of red-cell storage was not associated with significant differences in the change in MODS. We did not find that the transfusion of red cells stored for 10 days or less was superior to the transfusion of red cells stored for 21 days or more among patients 12 years of age or older who were undergoing complex cardiac surgery. (Funded by the National Heart, Lung, and Blood Institute; RECESS ClinicalTrials.gov number, NCT00991341.).

Age of transfused blood in critically ill adults

BACKGROUND

Fresh red cells may improve outcomes in critically ill patients by enhancing oxygen delivery while minimizing the risks of toxic effects from cellular changes and the accumulation of bioactive materials in blood components during prolonged storage.

METHODS

In this multicenter, randomized, blinded trial, we assigned critically ill adults to receive either red cells that had been stored for less than 8 days or standard-issue red cells (the oldest compatible units available in the blood bank). The primary outcome measure was 90-day mortality.

RESULTS

Between March 2009 and May 2014, at 64 centers in Canada and Europe, 1211 patients were assigned to receive fresh red cells (fresh-blood group) and 1219 patients were assigned to receive standard-issue red cells (standard-blood group). Red cells were stored a mean (±SD) of 6.1±4.9 days in the fresh-blood group as compared with 22.0±8.4 days in the standard-blood group (P<0.001). At 90 days, 448 patients (37.0%) in the fresh-blood group and 430 patients (35.3%) in the standard-blood group had died (absolute risk difference, 1.7 percentage points; 95% confidence interval [CI], -2.1 to 5.5). In the survival analysis, the hazard ratio for death in the fresh-blood group, as compared with the standard-blood group, was 1.1 (95% CI, 0.9 to 1.2; P=0.38). There were no significant between-group differences in any of the secondary outcomes (major illnesses; duration of respiratory, hemodynamic, or renal support; length of stay in the hospital; and transfusion reactions) or in the subgroup analyses.

CONCLUSIONS

Transfusion of fresh red cells, as compared with standard-issue red cells, did not decrease the 90-day mortality among critically ill adults. (Funded by the Canadian Institutes of Health Research and others; Current Controlled Trials number, ISRCTN44878718.).

A prospective study on red blood cell transfusion related hyperkalemia in critically ill patients

BACKGROUND

Transfusion-associated hyperkalemic cardiac arrest is a serious complication in patients receiving packed red blood cell (PRBC) transfusions. Mortality from hyperkalemia increases with large volumes of PRBC transfusion, increased rate of transfusion, and the use of stored PRBCs. Theoretically, hyperkalemia may be complicated by low cardiac output, acidosis, hyperglycemia, hypocalcemia, and hypothermia. In this study, we focus on transfusion-related hyperkalemia involving only medical intensive care unit (MICU) patients.

METHOD

This prospective observational study focuses on PRBC transfusions among MICU patients greater than 18 years of age. Factors considered during each transfusion included patient's diagnosis, indication for transfusion, medical co-morbidities, acid-base disorders, K(+) levels before and after each PRBC transfusion, age of stored blood, volume and rate of transfusion, and other adverse events. We used Pearson correlation and multivariate analysis for each factor listed above and performed a logistic regression analysis.

RESULTS

Between June 2011 and December 2011, 125 patients received a total of 160 units of PRBCs. Median age was 63 years (22 - 92 years). Seventy-one (57%) were females. Sixty-three patients (50%) had metabolic acidosis, 75 (60%) had acute renal failure (ARF), and 12 (10%) had end-stage renal disease (ESRD). Indications for transfusion included septic shock (n = 65, 52%), acute blood loss (n = 25, 20%), non-ST elevation myocardial infarction (NSTEMI) (n = 25, 20%) and preparation for procedures (n = 14, 11%). Baseline K(+) value was 3.9 ± 1.1 mEq/L compared to 4.3 ± 1.2 mEq/L post-transfusion respectively (P = 0.9). During this study period, 4% of patients developed hyperkalemia (K(+) 5.5 mEq/L or above). The mean change of serum potassium in patients receiving transfusion ≥ 12 days old blood was 4.1 ± 0.4 mEq/L compared to 4.8 ± 0.3 mEq/L (mean ± SD) in patients receiving blood 12 days or less old. Sixty-two patients (77.5%) that were transfused stored blood (for more than 12 days) had increased serum K(+); eight (17.7%) patients received blood that was stored for less than 12 days. In both univariate (P = 0.02) and multivariate (P = 0.04) analysis, findings showed that among all factors, transfusion of stored blood was the only factor that affected serum potassium levels (95% CI: 0.32 - 0.91). No difference was found between central and peripheral intravenous access (P = 0.12), acidosis (P = 0.12), ARF (P = 0.6), ESRD (P = 0.5), and multiple transfusions (P = 0.09). One subject developed a sustained cardiac arrest after developing severe hyperkalemia (K(+) = 9.0) following transfusion of seven units of PRBCs. Multivariate logistic regression showed linear correlation between duration of stored blood and serum K(+) (R(2) = 0.889).

CONCLUSION

This study assesses factors that affect K(+) in patients admitted to MICU. Results from the study show that rise in serum K(+) level is more pronounced in patients who receive stored blood (> 12 days). Future studies should focus on the use of altered storage solution, inclusion of potassium absorption filters during transfusion and cautious use of blood warmer in patients requiring massive blood transfusions.

Established and theoretical factors to consider in assessing the red cell storage lesion

The collection and storage of red blood cells (RBCs) is a logistical necessity to provide sufficient blood products. However, RBC storage is an unnatural state, resulting in complicated biological changes, referred to collectively as the "storage lesion." Specifics of the storage lesion have been studied for decades, including alterations to cellular properties, morphology, molecular biology of carbohydrates, proteins and lipids, and basic metabolism. Recently, mass spectrometry-based "omics" technology has been applied to the RBC storage lesion, resulting in many new observations, the initial effects of which are more information than understanding. Meanwhile, clinical research on RBC transfusion is considering both the efficacy and also the potential untoward effects of transfusing stored RBCs of different ages and storage conditions. The myriad biological changes that have now been observed during the storage lesion have been extensively reviewed elsewhere. This article focuses rather on an analysis of our current understanding of the biological effects of different elements of the storage lesion, in the context of evolving new clinical understanding. A synopsis is presented of both established and theoretical considerations of the RBC storage lesion and ongoing efforts to create a safer and more efficacious product.

The effect of processing method on the in vitro characteristics of red blood cell products

BACKGROUND AND OBJECTIVES

While the clinical impact of differences in red blood cell (RBC) component processing methods is unknown, there are concerns they may be confounding variables in studies such as the ongoing 'age of blood' investigations. Here, we compare the in vitro characteristics of red cell concentrates (RCCs) produced by several different processing methods.

MATERIALS AND METHODS

Nine processing methods were examined: three apheresis methods (Alyx, MCS+ and Trima), as well as leucoreduced whole blood-derived RCCs produced by buffy coat and whole blood filtration and non-leucoreduced RCCs. RCCs were stored in saline-adenine-glucose-mannitol or additive solutions (AS) 1 or 3 for 42 days, with quality tested on day 5 and day 42.

RESULTS

Many significant product differences were observed both early in and at the end of storage. Mean haemoglobin (Hb) ranged from 52 to 71 g/unit and mean Hct from 59·5 to 64·8%. Most RCC passed regulated quality control criteria according to Canadian Standards Association guidelines, although there were some failures relating to Hb content and residual WBC counts.

CONCLUSION

Processing method impacts RCC characteristics throughout storage; better understanding of these differences and reporting of processing method details is critical.

Differences in Rat and Human Erythrocytes Following Blood Component Manufacturing: The Effect of Additive Solutions

BACKGROUND

Small animal models have been previously used in transfusion medicine studies to evaluate the safety of blood transfusion products. Although there are multiple studies on the effects of blood banking practices on human red blood cells (RBCs), little is known about the effect of blood component manufacturing on the quality of rat RBCs.

METHODS

Blood from Sprague-Dawley rats and human volunteers (n = 6) was collected in CPD anticoagulant, resuspended in SAGM or AS3, and leukoreduced. In vitro quality was analyzed, including deformability, aggregation, microvesiculation, phosphatidylserine (PS) expression, percent hemolysis, ATP, 2,3-DPG, osmotic fragility, and potassium concentrations.

RESULTS

Compared to human RBCs, rat RBCs had decreased deformability, membrane rigidity, aggregability, and microvesiculation after component manufacturing process. Rat RBCs in SAGM showed higher hemolysis compared to human RBCs in SAGM (rat 4.70 ± 0.83% vs. human 0.34 ± 0.07%; p = 0.002). Rat RBCs in AS3 had greater deformability and rigidity than in SAGM. The number of microparticles/µl and the percentage PS expression were lower in rat RBCs in AS3 than in rat RBCs in SAGM. Hemolysis was also significantly lower in AS3 compared to SAGM (2.21 ± 0.68% vs. 0.87 ± 0.39%; p = 0.028).

CONCLUSION

Rat RBCs significantly differ from human RBCs in metabolic and membrane-related aspects. SAGM, which is commonly used for human RBC banking, causes high hemolysis and is not compatible with rat RBCs.