Purported deleterious effects of "old" versus "fresh" red blood cells: an updated meta-analysis

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.

Early Versus Delayed Umbilical Cord Clamping on Physiologic Anemia of the Term Newborn Infant

AIM

Our study aims to make a comparison between the effects of milking of umbilical cord versus delayed cord clamping on Hemoglobin level at 6 weeks from delivery among term neonates and which method is more beneficial for them.

DESIGN

It was a randomised control study. Participants were randomised into 2 groups; Group 1: 125 women were assigned to delay cord clamping; Group 2: 125 women were assigned to milking of the umbilical cord 5 times before cutting. Student t-test was used to compare between the two groups for quantitative data, for qualitative data chi-square test and the Correlation coefficient was done to test the association between variables.

SETTING

This study was at El-Galaa Teaching Hospital, labour suite. Cairo, Egypt.

PARTICIPANTS

A group of 250 pregnant women starting from ≥ 37 weeks' gestational age.

INTERVENTION

In this study, we searched if the mechanism of milking or delayed cord clamping could give some of the positive benefits for neonates or not.

RESULTS

In this study, we found that milking of the umbilical cord five times as in group 1 was associated with higher hemoglobin levels at 6 weeks after birth, at physiological anemia of the fetus and significant but clinically there was no difference between the two groups (10.4 ± 0.5 and 10.6 ± 0.5 respectively, P < 0.001). Also, there was a positive correlation between haemoglobin of the mother and the newborn during the first day and after 6 weeks with r = 0.349 and 0.283 respectively and a P value < 0.001. Furthermore, there was a positive correlation between the haemoglobin of the fetus after the first day and fetus at 6 weeks with r = 0.534 and a P value < 0.001. For most other outcomes (including APGAR score, positive pressure ventilation, poor neonatal outcomes such as respiratory distress syndrome there were no significant differences between the two groups. Our study may recommend the use of umbilical cord milking in term babies when delayed cord clamping is unavailable.

CONCLUSION

Umbilical cord blood milking after its clamping improves some important haematological parameters for newborns, especially in countries with high incidence of anaemia in newborns and children.

Perioperative Allogeneic Red Blood-Cell Transfusion Associated with Surgical Site Infection After Total Hip and Knee Arthroplasty

BACKGROUND

Perioperative allogeneic red blood-cell transfusion is a suspected risk factor for surgical site infection (SSI) after total joint arthroplasty (TJA), but the interrelationships among SSI risk, transfusion dose, preoperative anemia, and the presence of coagulopathies have not been well described.

METHODS

Data on SSI within 1 year after surgery as well as on transfusion with blood products within 30 days after surgery were obtained for 6,788 patients who had undergone primary or revision total hip or knee arthroplasty from 2000 to 2011 in a single hospital system. Multivariate logistic regression modeling was used to determine the independent association between allogeneic red blood-cell transfusion and SSI.

RESULTS

There was a dose-dependent association between allogeneic red blood-cell transfusion and SSI, with the infection rate increasing as the transfusion dose increased from 1 unit (odds ratio [OR] = 1.97; 95% confidence interval [CI] = 1.38, 2.79; p < 0.001), to 2 units (OR = 2.20; CI = 1.37, 3.44; p = 0.002), to 3 units (OR = 3.66; CI = 1.72, 7.16; p = 0.001), and to >3 units (OR = 7.40; CI = 4.91, 11.03; p < 0.001) after controlling for medical comorbidities, planned procedure, preoperative anemia, and preexisting coagulopathies. A preexisting bleeding disorder (OR = 2.09; CI = 1.57, 2.80; p < 0.001) and clotting disorder (OR = 1.37; CI = 1.14, 1.64; p = 0.001) and preoperative anemia (OR = 3.90; CI = 3.31, 4.61; p < 0.001) were all independent risk factors for transfusion after adjusting for the planned procedure.

CONCLUSIONS

We found a dose-dependent relationship between allogeneic red blood-cell transfusion and SSI risk after total hip or knee arthroplasty. Additionally, preoperative anemia or a known bleeding or clotting disorder were risk factors for the need for allogeneic red blood-cell transfusion. Our findings underscore the need for preoperative risk assessment, methods to limit surgical tissue injury, and optimized blood conservation strategies.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Procoagulant activity in stored units of red blood cells

The procoagulant activity (PA) of stored units of red blood cells (RBC) increases over time, which is related to the expression/exposure of tissue factor (TF). However, there is a discrepancy between the TF measured and changes in PA observed, suggesting that other blood components contribute to this activity. Our goal was to evaluate changes in PA of stored RBCs and to determine possible contributors to it. RBC units from 4 healthy donors were prepared and stored at 4 °C. On selected days, RBC aliquots were reconstituted with autologous plasma and tested in the thromboelastography assay. Corresponding supernatants were tested in a clotting assay. For all donors, the clotting time (CT) of reconstituted RBC units decreased from ∼3000-4000s on day 1 to ∼1000-1600s on day 30, with the most dramatic changes occurring between days 1 and 5. Anti-TF antibody slightly prolonged the CT. The concentration of TF did not change significantly over time and was within the range of 0.3-2.3 pM. Bovine lactadherin (LTD) prolonged the CT of the RBC (by 2.4-3.4-fold in days 3-5 and by 1.3-1.8-fold at day 30). Anti-TF antibody together with LTD had a cumulative effect on the CT prolongation. CT of supernatants responded to both anti-TF and anti-FXIa antibodies. Three contributors to the PA of stored RBC were identified, i.e. FXIa in solution and phosphatidylserine and TF exposed on blood cells and microparticles. Failure of LTD and antibodies to completely eliminate PA suggests that other components of blood could contribute to it.

Transfusion of fresher vs older red blood cells in hospitalized patients: a systematic review and meta-analysis

The impact of transfusing fresher vs older red blood cells (RBCs) on patient-important outcomes remains controversial. Two recently published large trials have provided new evidence. We summarized results of randomized trials evaluating the impact of the age of transfused RBCs. We searched MEDLINE, EMBASE, CINAHL, the Cochrane Database for Systematic Reviews, and Cochrane CENTRAL for randomized controlled trials enrolling patients who were transfused fresher vs older RBCs and reported outcomes of death, adverse events, and infection. Independently and in duplicate, reviewers determined eligibility, risk of bias, and abstracted data. We conducted random effects meta-analyses and rated certainty (quality or confidence) of evidence using the GRADE approach. Of 12 trials that enrolled 5229 participants, 6 compared fresher RBCs with older RBCs and 6 compared fresher RBCs with current standard practice. There was little or no impact of fresher vs older RBCs on mortality (relative risk [RR], 1.04; 95% confidence interval [CI], 0.94-1.14; P = .45; I2 = 0%, moderate certainty evidence) or on adverse events (RR, 1.02; 95% CI, 0.91-1.14; P = .74; I2 = 0%, low certainty evidence). Fresher RBCs appeared to increase the risk of nosocomial infection (RR, 1.09; 95% CI, 1.00-1.18; P = .04; I2 = 0%, risk difference 4.3%, low certainty evidence). Current evidence provides moderate certainty that use of fresher RBCs does not influence mortality, and low certainty that it does not influence adverse events but could possibly increase infection rates. The existing evidence provides no support for changing practices toward fresher RBC transfusion.

Blood Products

Perioperative hemorrhage, anemia, thrombocytopenia, and coagulopathy are common in the surgical intensive care unit. As a result, blood product transfusion occurs frequently. While red blood cell, plasma, and platelet transfusions have a lifesaving role in the resuscitation of patients with trauma and hemorrhagic shock, their application in other settings is under scrutiny. Current data would suggest a conservative approach be taken, thus avoiding unnecessary transfusion and associated potential adverse events. New and developmental products such as prothrombin complex concentrates offer appealing alternatives to traditional transfusion practice—potentially with fewer risks—however, further investigation into their safety and efficacy is required before practice change can take place.

Clinical effects of red blood cell storage

BACKGROUND

Well-characterized biochemical, structural, and physiological changes occur when red blood cells (RBCs) are stored for a period of time and are collectively called the storage lesion.

METHODS

Key study results are summarized and contrasted and new data from recently completed randomized controlled trials will be discussed.

RESULTS

It is unclear whether in vitro changes to RBCs that occur during storage are clinically relevant. The clinical effects of RBC storage have been the focus of observational studies in recent years. However, these studies lack any consensus, possibly because of methodological limitations.

CONCLUSIONS

The clinical significance of storing RBCs is controversial, although new data from randomized controlled trials of neonates and patients undergoing cardiac surgery suggest that the duration of RBC storage is not associated with adverse clinical outcomes in these patient populations.

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.

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.

Clinical transfusion practice update: haemovigilance, complications, patient blood management and national standards

Blood transfusion is not without risk. Although the risks of HIV and hepatitis transmission have diminished, haemovigilance programs highlight that other significant transfusion hazards remain. Sepsis from bacterial contamination is the most common residual infectious hazard in developed countries, and events due to clerical error are problematic. Unnecessary transfusions should be avoided. New national guidelines on patient blood management (PBM) emphasise holistic approaches, including strategies to reduce transfusion requirements. Perioperative PBM should incorporate preoperative haemoglobin and medication optimisation, intraoperative blood conservation, and consideration of restrictive postoperative transfusion and cell-salvage techniques. When massive transfusion is required, hospitals should implement massive transfusion protocols. These protocols reduce mortality, improve communication and facilitate adequate provision of blood products. They should include multidisciplinary team involvement and guidelines for use of blood components and adjunctive agents. Although fresh frozen plasma to red blood cell and platelet to red blood cell ratios of ≥ 1 : 2 appear to reduce mortality in trauma patients who receive massive transfusion, there is insufficient evidence to recommend specific ratios. Systematic reviews have found no significant benefit of recombinant activated factor VII in critical bleeding, and an increase in thromboembolic events; specialist haematology advice is therefore recommended when considering use of this agent. The National Safety and Quality Health Service Standards address use of blood and blood products, and provide important transfusion principles for adoption by all clinicians. Storage of red cells in additive solution results in changes, known as the "storage lesion", and studies to determine the clinical effect of the age of blood at transfusion are ongoing.

Relationship between red cell storage duration and outcomes in adults receiving red cell transfusions: a systematic review

INTRODUCTION

The duration of red blood cell (RBC) storage before transfusion may alter RBC function and supernatant and, therefore, influence the incidence of complications or even mortality.

METHODS

A MEDLINE search from 1983 to December 2012 was performed to identify studies reporting age of transfused RBCs and mortality or morbidity in adult patients.

RESULTS

Fifty-five studies were identified; most were single-center (93%) and retrospective (64%), with only a few, small randomized studies (eight studies, 14.5%). The numbers of subjects included ranged from eight to 364,037. Morbidity outcomes included hospital and intensive care unit (ICU) length of stay (LOS), infections, multiple organ failure, microcirculatory alterations, cancer recurrence, thrombosis, bleeding, vasospasm after subarachnoid hemorrhage, and cognitive dysfunction. Overall, half of the studies showed no deleterious effects of aged compared to fresh blood on any endpoint. Eleven of twenty-two (50%) studies reported no increased mortality, three of nine (33%) showed no increased LOS with older RBCs and eight of twelve (66%) studies showed no increased risks of organ failure. Ten of eighteen (55%) studies showed increased infections with transfusion of older RBCs. The considerable heterogeneity among studies and numerous methodological flaws precluded a formal meta-analysis.

CONCLUSIONS

In this systematic review, we could find no definitive argument to support the superiority of fresh over older RBCs for transfusion.