A pilot randomized trial comparing symptomatic vs. hemoglobin-level-driven red blood cell transfusions following hip fracture

Restrictive versus Liberal blood transfusion strategies for patients undergoing orthopedic surgery: a meta-analysis of randomised trials with trial sequential analysis

BACKGROUND

A meta-analysis was conducted to explore the prognostic differences of restrictive blood transfusion (RBT) versus liberal blood transfusion (LBT) strategies in orthopedic patients.

METHODS

A comprehensive search was performed in PubMed, Embase, Cochrane Central Register of Controlled Trials, Embase, and clinicaltrials.gov up to 20 October 2024. The quality of included studies was assessed according to Cochrane risk of bias, and quality of evidence was assessed using the GRADE system. We performed sensitivity and publication bias analyses and used trial sequential analysis (TSA) to assess the risk of random error in the analysis results.

RESULTS

19 studies involving 7833 patients were included in the analysis. Compared with LBT, RBT reduced transfusion rate and increased the occurrence of cardiovascular events (RR = 1.44; 95% CI: 1.15-1.80, P = 0.001; I2 = 0%), mainly increased myocardial infarction (RR = 1.70; 95% CI: 1.16-2.48, P = 0.006; I2 = 0%) rather than congestive heart failure. There were no significant differences between transfusion strategies in infection, thrombotic events, mortality, delirium and length of hospitalization. Results of subgroup analyses indicate that in patients at high risk for cardiovascular disease, RBT increases the risk of myocardial infarction and length of hospitalization. In addition, RBT are associated with lower overall infection rates and shorter length of hospitalization after joint replacement or revision surgery; and are associated with an increased risk of myocardial infarction after fracture repair surgery (RR = 1.79; 95% CI: 1.21-2.65, P = 0.004). The TSA results show that transfusion rate and mortality (≥ 60 days) have reached the required information size. However, the evidence regarding the efficacy for the remaining outcomes analyzed remains inconclusive, likely due to insufficient numbers of patients in the existing studies.

CONCLUSIONS

Compared with LBT, RBT increases the risk of cardiovascular events in orthopedic patients but does not affect adverse outcomes such as infection, thrombotic events, mortality, and delirium.

TRIAL REGISTRATION

No patients were involved in this study.

Red Blood Cell Transfusion: 2023 AABB International Guidelines

Importance

Red blood cell transfusion is a common medical intervention with benefits and harms.

Objective

To provide recommendations for use of red blood cell transfusion in adults and children.

Evidence Review

Standards for trustworthy guidelines were followed, including using Grading of Recommendations Assessment, Development and Evaluation methods, managing conflicts of interest, and making values and preferences explicit. Evidence from systematic reviews of randomized controlled trials was reviewed.

Findings

For adults, 45 randomized controlled trials with 20 599 participants compared restrictive hemoglobin-based transfusion thresholds, typically 7 to 8 g/dL, with liberal transfusion thresholds of 9 to 10 g/dL. For pediatric patients, 7 randomized controlled trials with 2730 participants compared a variety of restrictive and liberal transfusion thresholds. For most patient populations, results provided moderate quality evidence that restrictive transfusion thresholds did not adversely affect patient-important outcomes. Recommendation 1: for hospitalized adult patients who are hemodynamically stable, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). In accordance with the restrictive strategy threshold used in most trials, clinicians may choose a threshold of 7.5 g/dL for patients undergoing cardiac surgery and 8 g/dL for those undergoing orthopedic surgery or those with preexisting cardiovascular disease. Recommendation 2: for hospitalized adult patients with hematologic and oncologic disorders, the panel suggests a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (conditional recommendations, low certainty evidence). Recommendation 3: for critically ill children and those at risk of critical illness who are hemodynamically stable and without a hemoglobinopathy, cyanotic cardiac condition, or severe hypoxemia, the international panel recommends a restrictive transfusion strategy considering transfusion when the hemoglobin concentration is less than 7 g/dL (strong recommendation, moderate certainty evidence). Recommendation 4: for hemodynamically stable children with congenital heart disease, the international panel suggests a transfusion threshold that is based on the cardiac abnormality and stage of surgical repair: 7 g/dL (biventricular repair), 9 g/dL (single-ventricle palliation), or 7 to 9 g/dL (uncorrected congenital heart disease) (conditional recommendation, low certainty evidence).

Conclusions and Relevance

It is good practice to consider overall clinical context and alternative therapies to transfusion when making transfusion decisions about an individual patient.

An analysis of quality of life and functional outcomes as reported in randomized trials for red cell transfusions

BACKGROUND

Meta-analyses of randomized controlled trials (RCTs) evaluating thresholds for red blood cell (RBC) transfusion typically focus on mortality; however, other outcomes are highly relevant. The aim of this study is to summarize the effects of different transfusion thresholds on the outcomes of quality of life (QoL) and function.

STUDY DESIGN

We extracted data from RCTs identified in a recently published Cochrane systematic review. Primary analysis was descriptive.

RESULTS

A total of 23 RCTs with 13,743 adult participants were included. Fifteen RCTs included patients in the postoperative period, of which 9 RCTs were conducted in hip (n = 3024) and 6 (n = 8672) in cardiac surgeries; 5 RCTs (n = 489) were in patients with hematological malignancies; 2 in the setting of bleeding (gastrointestinal bleed [n = 936] and postpartum [n = 521]); and one RCT (n = 936) included critically ill patients. QoL and function were reported using a variety of questionnaires and tools. The timing of assessments varied between trials. No clear clinical differences in QoL outcomes were identified in comparisons between restrictive and liberal transfusion thresholds.

DISCUSSION

There is no evidence that a liberal transfusion strategy improves QoL and functional outcomes. However, the substantial limitations of many included studies indicate the need for further well-designed and adequately powered trials.

Perioperative interventions to improve early mobilisation and physical function after hip fracture: a systematic review and meta-analysis

BACKGROUND

Perioperative interventions could enhance early mobilisation and physical function after hip fracture surgery.

OBJECTIVE

Determine the effectiveness of perioperative interventions on early mobilisation and physical function after hip fracture.

METHODS

Ovid MEDLINE, CINAHL, Embase, Scopus and Web of Science were searched from January 2000 to March 2022. English language experimental and quasi-experimental studies were included if patients were hospitalised for a fractured proximal femur with a mean age 65 years or older and reported measures of early mobilisation and physical function during the acute hospital admission. Data were pooled using a random effect meta-analysis.

RESULTS

Twenty-eight studies were included from 1,327 citations. Studies were conducted in 26 countries on 8,192 participants with a mean age of 80 years. Pathways and models of care may provide a small increase in early mobilisation (standardised mean difference [SMD]: 0.20, 95% confidence interval [CI]: 0.01-0.39, I2 = 73%) and physical function (SMD: 0.07, 95% CI 0.00 to 0.15, I2 = 0%) and transcutaneous electrical nerve stimulation analgesia may provide a moderate improvement in function (SMD: 0.65, 95% CI: 0.24-1.05, I2 = 96%). The benefit of pre-operative mobilisation, multidisciplinary rehabilitation, recumbent cycling and clinical supervision on mobilisation and function remains uncertain. Evidence of no effect on mobilisation or function was identified for pre-emptive analgesia, intraoperative periarticular injections, continuous postoperative epidural infusion analgesia, occupational therapy training or nutritional supplements.

CONCLUSIONS

Perioperative interventions may improve early mobilisation and physical function after hip fracture surgery. Future studies are needed to model the causal mechanisms of perioperative interventions on mobilisation and function after hip fracture.

Impact of restrictive red blood cell transfusion strategy on thrombosis-related events: A meta-analysis and systematic review

BACKGROUND AND OBJECTIVES

There is an ongoing controversy regarding the risks of restrictive and liberal red blood cell (RBC) transfusion strategies. This meta-analysis assessed whether transfusion at a lower threshold was superior to transfusion at a higher threshold, with regard to thrombosis-related events, that is, whether these outcomes can benefit from a restrictive transfusion strategy is debated.

MATERIALS AND METHODS

We searched PubMed, Cochrane Central Register of Controlled Trials and Scopus from inception up to 31 July 2021. We included randomized controlled trials (RCTs) in any clinical setting that evaluated the effects of restrictive versus liberal RBC transfusion in adults. We used random-effects models to calculate the risk ratios (RRs) and 95% confidence intervals (CIs) based on pooled data.

RESULTS

Thirty RCTs involving 17,334 participants were included. The pooled RR for thromboembolic events was 0.65 (95% CI 0.44-0.94; p = 0.020; I²  = 0.0%, very low-quality evidence), favouring the restrictive strategy. There were no significant differences in cerebrovascular accidents (RR = 0.83; 95% CI 0.64-1.09; p = 0.180; I²  = 0.0%, very low-quality evidence) or myocardial infarction (RR = 1.05; 95% CI 0.87-1.26; p = 0.620; I²  = 0.0%, low-quality evidence). Subgroup analyses showed that a restrictive (relative to liberal) strategy reduced (1) thromboembolic events in RCTs conducted in North America and (2) myocardial infarctions in the subgroup of RCTs where the restrictive transfusion threshold was 7 g/dl but not in the 8 g/dl subgroup (with a liberal transfusion threshold of 10 g/dl in both subgroups).

CONCLUSIONS

A restrictive (relative to liberal) transfusion strategy may be effective in reducing venous thrombosis but not arterial thrombosis.

Transfusion thresholds for guiding red blood cell transfusion

BACKGROUND

The optimal haemoglobin threshold for use of red blood cell (RBC) transfusions in anaemic patients remains an active field of research. Blood is a scarce resource, and in some countries, transfusions are less safe than in others because of inadequate testing for viral pathogens. If a liberal transfusion policy does not improve clinical outcomes, or if it is equivalent, then adopting a more restrictive approach could be recognised as the standard of care.  OBJECTIVES: The aim of this review update was to compare 30-day mortality and other clinical outcomes for participants randomised to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all clinical conditions. The restrictive transfusion threshold uses a lower haemoglobin concentration as a threshold for transfusion (most commonly, 7.0 g/dL to 8.0 g/dL), and the liberal transfusion threshold uses a higher haemoglobin concentration as a threshold for transfusion (most commonly, 9.0 g/dL to 10.0 g/dL).

SEARCH METHODS

We identified trials through updated searches: CENTRAL (2020, Issue 11), MEDLINE (1946 to November 2020), Embase (1974 to November 2020), Transfusion Evidence Library (1950 to November 2020), Web of Science Conference Proceedings Citation Index (1990 to November 2020), and trial registries (November 2020). We  checked the reference lists of other published reviews and relevant papers to identify additional trials. We were aware of one trial identified in earlier searching that was in the process of being published (in February 2021), and we were able to include it before this review was finalised.

SELECTION CRITERIA

We included randomised trials of surgical or medical participants that recruited adults or children, or both. We excluded studies that focused on neonates. Eligible trials assigned intervention groups on the basis of different transfusion schedules or thresholds or 'triggers'. These thresholds would be defined by a haemoglobin (Hb) or haematocrit (Hct) concentration below which an RBC transfusion would be administered; the haemoglobin concentration remains the most commonly applied marker of the need for RBC transfusion in clinical practice. We included trials in which investigators had allocated participants to higher thresholds or more liberal transfusion strategies compared to more restrictive ones, which might include no transfusion. As in previous versions of this review, we did not exclude unregistered trials published after 2010 (as per the policy of the Cochrane Injuries Group, 2015), however, we did conduct analyses to consider the differential impact of results of trials for which prospective registration could not be confirmed.   DATA COLLECTION AND ANALYSIS: We identified trials for inclusion and extracted data using Cochrane methods. We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two review authors independently extracted data and assessed risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as being in the 'restrictive transfusion' group and those randomly allocated to the higher transfusion threshold as being in the 'liberal transfusion' group.

MAIN RESULTS

A total of 48 trials, involving data from 21,433 participants (at baseline), across a range of clinical contexts (e.g. orthopaedic, cardiac, or vascular surgery; critical care; acute blood loss (including gastrointestinal bleeding); acute coronary syndrome; cancer; leukaemia; haematological malignancies), met the eligibility criteria. The haemoglobin concentration used to define the restrictive transfusion group in most trials (36) was between 7.0 g/dL and 8.0 g/dL.  Most trials included only adults; three trials focused on children. The included studies were generally at low risk of bias for key domains including allocation concealment and incomplete outcome data. Restrictive transfusion strategies reduced the risk of receiving at least one RBC transfusion by 41% across a broad range of clinical contexts (risk ratio (RR) 0.59, 95% confidence interval (CI) 0.53 to 0.66; 42 studies, 20,057 participants; high-quality evidence), with a large amount of heterogeneity between trials (I² = 96%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.99, 95% CI 0.86 to 1.15; 31 studies, 16,729 participants; I² = 30%; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (all high-quality evidence)). High-quality evidence shows that the liberal transfusion threshold did not affect the risk of infection (pneumonia, wound infection, or bacteraemia). Transfusion-specific reactions are uncommon and were inconsistently reported within trials. We noted less certainty in the strength of evidence to support the safety of restrictive transfusion thresholds for the following predefined clinical subgroups: myocardial infarction, vascular surgery, haematological malignancies, and chronic bone-marrow disorders.

AUTHORS' CONCLUSIONS

Transfusion at a restrictive haemoglobin concentration decreased the proportion of people exposed to RBC transfusion by 41% across a broad range of clinical contexts. Across all trials, no evidence suggests that a restrictive transfusion strategy impacted 30-day mortality, mortality at other time points, or morbidity (i.e. cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. Despite including 17 more randomised trials (and 8846 participants), data remain insufficient to inform the safety of transfusion policies in important and selected clinical contexts, such as myocardial infarction, chronic cardiovascular disease, neurological injury or traumatic brain injury, stroke, thrombocytopenia, and cancer or haematological malignancies, including chronic bone marrow failure.  Further work is needed to improve our understanding of outcomes other than mortality. Most trials compared only two separate thresholds for haemoglobin concentration, which may not identify the actual optimal threshold for transfusion in a particular patient. Haemoglobin concentration may not be the most informative marker of the need for transfusion in individual patients with different degrees of physiological adaptation to anaemia. Notwithstanding these issues, overall findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds between the range of 7.0 g/dL and 8.0 g/dL. Some patient subgroups might benefit from RBCs to maintain higher haemoglobin concentrations; research efforts should focus on these clinical contexts.

Intraoperative Red Blood Cell Transfusion Decision-making: A Systematic Review of Guidelines

OBJECTIVES

The objective of this work was to carry out a systematic review of clinical practice guidelines (CPGs) pertaining to intraoperative red blood cell (RBC) transfusions, in terms of indications, decision-making, and supporting evidence base.

SUMMARY OF BACKGROUND DATA

RBC transfusions are common during surgery and there is evidence of wide variability in practice.

METHODS

Major electronic databases (MEDLINE, EMBASE, and CINAHL), guideline clearinghouses and Google Scholar were systematically searched from inception to January 2019 for CPGs pertaining to indications for intraoperative RBC transfusion. Eligible guidelines were retrieved and their quality assessed using AGREE II. Relevant recommendations were abstracted and synthesized to allow for a comparison between guidelines.

RESULTS

Ten guidelines published between 1992 and 2018 provided indications for intraoperative transfusions. No guideline addressed intraoperative transfusion decision-making as its primary focus. Six guidelines provided criteria for transfusion based on hemoglobin (range 6.0-10.0 g/dL) or hematocrit (<30%) triggers. In the absence of objective transfusion rules, CPGs recommended considering other parameters such as blood loss (n = 7), signs of end organ ischemia (n = 5), and hemodynamics (n = 4). Evidence supporting intraoperative recommendations was extrapolated primarily from the nonoperative setting. There was wide variability in the quality of included guidelines based on AGREE II scores.

CONCLUSION

This review has identified several clinical practice guidelines providing recommendations for intraoperative transfusion. The existing guidelines were noted to be highly variable in their recommendations and to lack a sufficient evidence base from the intraoperative setting. This represents a major knowledge gap in the literature.

Liberal blood transfusion strategies and associated infection in orthopedic patients: A meta-analysis

OBJECTIVE

It remains unclear whether transfusion strategies during orthopedic surgery and infection are related. The purpose of this study is to evaluate whether liberal blood transfusion strategies contribute to infection risk in orthopedic patients by analyzing randomized controlled trials (RCTs).

METHODS

RCTs with liberal versus restrictive red blood cell (RBC) transfusion strategies were identified by searching PubMed, Embase, the Cochrane Central Register of Controlled Trials from their inception to July 2019. Ten studies with infections as outcomes were included in the final analysis. According to the Jadad scale, all studies were considered to be of high quality.

RESULTS

Ten trials involving 3938 participants were included in this study. The pooled risk ratio (RR) for the association between liberal transfusion strategy and infection was 1.34 (95% confidence intervals [CI], 0.94-1.90; P = .106). The sensitivity analysis indicated unstable results, and no significant publication bias was observed.

CONCLUSION

This pooled analysis of RCTs demonstrates that liberal transfusion strategies in orthopedic patients result in a nonsignificant increase in infections compared with more restrictive strategies. The conclusions are mainly based on retrospective studies and should not be considered as recommendation before they are supported by larger scale and well-designed RCTs.

Rethinking strategies for blood transfusion in hip fracture patients

OBJECTIVES

Most patients can tolerate a hemoglobin (Hgb) > 8 g per deciliter. In some cases, however, transfusion will delay physical therapy and hospital discharge. This study aims to review Hgb and transfusion data for a large volume of recent hip fracture patients in order to identify new opportunities for decreasing the length of hospital stay. Our hypotheses are that in some cases, earlier transfusion of more blood will be associated with shorter hospital stays, and that Hgb levels consistently decrease for more than 3 days postoperatively.

DESIGN

Retrospective chart review.

SETTING

Two academic medical centers with Geriatric Fracture Programs.

PATIENTS

Data was collected from patients 50 years and older with hip fractures April 2015 and October 2017.

INTERVENTION

Operative stabilization of the hip fractures according to standard of care for the fracture type and patient characteristics. Transfusion according to established standards.

MAIN OUTCOME MEASUREMENTS

Electronic records were retrospectively reviewed for demographic information, Hgb levels, and transfusion events.

RESULTS

One thousand fifteen patients with femoral neck or intertrochanteric hip fractures were identified. Eight hundred sixty met the inclusion criteria. The average length of hospital stay was 6.7 days. The mean patient age was 82 years. The average American Society of Anesthesiologists score was 2.9. The average Hgb level consistently decreased for 5 days postoperatively before beginning to increase on day 6. There was poor consistency between intraoperative Hgb levels and preoperative or postoperative Hgb levels. Three hundred sixty-eight (42.8%) patients were transfused an average of 1.9 (range 1-6) units. One hundred five patients required a transfusion on postoperative day (POD) 1: 72 received only 1 unit of blood: 36 (50%) of the 72 required a second transfusion in the following days, compared to 9 of 33 (27%) who received 2 units on POD 1 (χ2 = 3.8898; P < .05). Patients who received transfusions on POD 3 or later had an average length of stay >2.5 days longer than those who received a transfusion earlier (P = 0.005).

CONCLUSIONS

Our findings do not support earlier transfusion of more blood. Although in some cases, there is an association between earlier transfusion of more blood and shorter hospital stay, routine transfusion of more blood would incur higher transfusion risks in some patients who would not otherwise meet criteria for transfusion. After hip fracture surgery, the Hgb usually decreases for 5 days and does not begin to increase until POD 6. This information will provide utility in the population health management of hip fracture patients.

LEVEL OF EVIDENCE

Level III, Retrospective Cohort Study.

Prolonged operative time increases risk of blood loss and transfusion requirements in revision hip surgery

INTRODUCTION

Revision hip surgery is well documented to have a high association with substantial blood loss and the associated need for a blood transfusion. This exposes the patient to increased risk of transfusion reaction and blood borne infection. There are many strategies to minimize allogeneic transfusion rates in revision surgery such as pre-operative autologous donation, peri-operative tranexamic acid, thrombin sealants, normovolaemic haemodilution, intra-operative blood salvage and the use of post-operative autologous drains.

PATIENTS AND METHODS

We prospectively looked at 177 consecutive cases performed at one centre by a single surgical and anaesthetic team to identify which patient and operative factors were most significant in minimizing the requirement for an allogeneic blood transfusion.

RESULTS

Our results identified the duration of surgery as being the only significant variable affecting the level of blood loss. We noted a 3% increase in the probability of massive blood loss (> 2000 mls) for every minute of increased surgical time in our series.

CONCLUSIONS

We conclude that measures to minimize the duration of surgery would be beneficial in reducing blood loss and the risks of requiring blood transfusions in revision hip surgery.

Cost-effectiveness comparison of routine transfusion with restrictive and liberal transfusion strategies for surgical patients in China

BACKGROUND AND OBJECTIVES

A health industry standard recommending restrictive transfusion is to be in effect in China in April 2019. We aim to explore its potential economic and clinical impacts among surgical patients.

MATERIALS AND METHODS

A decision tree model was applied to compare cost-effectiveness of current routine transfusion in China, a restrictive (transfusion at Hb < 8 g/dl or ischaemic symptoms) and a liberal (transfusion at Hb < 10 g/dl) strategy. Parameters were estimated from empirical data of 25 227 surgical inpatients aged ≥30 years in a multicenter study and supplemented by meta-analysis when necessary. Results are shown for cardio-cerebral-vascular (CCV) surgery and non-CCV (orthopaedics, general, thoracic) surgery separately.

RESULTS

Per 10 000 patients in routine, restrictive, liberal transfusion scenarios, total spending (transfusion and length of stay related) was 7·67, 7·58 and 9·39 million CNY (1 CNY × 0.157 = 1 US dollar) for CCV surgery and 6·35, 6·70 and 8·09 million CNY for non-CCV surgery; infectious and severe complications numbered 354, 290, and 290 (CCV) and 315, 286, and 330 (non-CCV), respectively. Acceptability curves showed high probabilities for restrictive strategy to be cost-effective across a wide range of willingness-to-pay values. Such findings were mostly consistent in sensitivity and subgroup analyses except for patients with cardiac problems.

CONCLUSION

We showed strong rationale, succeeding previous findings only in cardiac or joint procedures, to comply with the new standard as restrictive transfusion has high potential to save blood, secure safety, and is cost-effective for a wide spectrum of surgical patients. Experiences should be further summarized to pave the way towards individualized transfusion.

Restrictive versus liberal strategy for red blood-cell transfusion in hip fracture patients: A systematic review and meta-analysis

BACKGROUND

Most clinical guidelines recommend a restrictive red-blood-cell (RBC) transfusion threshold. However, indications for transfusion in patients with a hip fracture have not been definitively evaluated or remain controversial. We compared the pros and cons of restrictive versus liberal transfusion strategies in patients undergoing hip fracture surgery.

METHODS

Electronic databases were searched to identify randomized controlled trials (RCTs) and retrospective cohort studies (RCSs) to investigate the effects of a restrictive strategy versus its liberal counterpart in patients undergoing hip fracture surgery. The main clinical outcomes included delirium, mortality, infections, cardiogenic complications, thromboembolic events, cerebrovascular accidents, and length of hospital stay. The meta-analysis program of the Cochrane Collaboration (RevMan version 5.3.0) was used for data analysis. Statistical heterogeneity was assessed by both Cochran chi-squared test (Q test) and I test. Both Begg and Egger tests were used to assess potential publication bias.

RESULTS

We identified 7 eligible RCTs and 2 eligible RCSs, involving 3,575 patients in total. In patients undergoing hip fracture surgery, we found no differences in frequency of delirium, mortality, the incidence rates of all infections, pneumonia, wound infection, all cardiovascular events, congestive heart failure, thromboembolic events or length of hospital stay between restrictive and liberal thresholds for RBC transfusion (P >.05). However, we found that the use of restrictive transfusion thresholds is associated with higher rates of acute coronary syndrome (P <.05) while liberal transfusion thresholds increase the risk of cerebrovascular accidents (P <.05).

CONCLUSION

In patients undergoing hip fracture surgery, clinicians should evaluate the patient's condition in detail and adopt different transfusion strategies according to the patient's specific situation rather than merely using a certain transfusion strategy.

Review of available evidence supporting different transfusion thresholds in different patient groups with anemia

In patients with anemia, transfusion of red blood cells (RBCs) can save lives and improve quality of life. The choice to transfuse should be cautiously made owing to risks of transfusion, economic costs, and limitations on the blood supply. Until the 1980s, the decision for RBC transfusion was guided by Hb threshold, with the aim of maintaining the patient's blood Hb level over 100 grams per liter. Since then, multiple randomized controlled trials and key systematic reviews have provided evidence-based guidelines as to appropriate transfusion thresholds in a number of clinical settings. Here, we aimed to address the outcome of defining different anemia criteria in specific clinical populations exclusively on the basis of the need for RBC transfusion based on Hb concentration. We focused on the patient populations, where there were the most available data on differing transfusion thresholds, which looked at transfusing to a higher or liberal transfusion threshold in comparison with a lower or restrictive transfusion threshold. These included patients in intensive care with or without septic shock, hip fracture surgery, cardiovascular surgery, and upper gastrointestinal bleeding, the pediatric population, and also those with malaria, by reviewing key randomized controlled trials and systematic reviews. Twenty-four randomized controlled studies and 12 systematic reviews have been included, and these are discussed below.

Should Transfusion Trigger Thresholds Differ for Critical Care Versus Perioperative Patients? A Meta-Analysis of Randomized Trials

Supplemental Digital Content is available in the text.

Objective:

To address the significant uncertainty as to whether transfusion thresholds for critical care versus surgical patients should differ.

Design:

Meta-analysis of randomized controlled trials.

Setting:

Medline, EMBASE, and Cochrane Library searches were performed up to 15 June 2016.

Patients:

Trials had to enroll adult surgical or critically ill patients for inclusion.

Interventions:

Studies had to compare a liberal versus restrictive threshold for the transfusion of allogeneic packed RBCs.

Measurements and Main Results:

The primary outcome was 30-day all-cause mortality, sub-grouped by surgical and critical care patients. Secondary outcomes included myocardial infarction, stroke, renal failure, allogeneic blood exposure, and length of stay. Odds ratios and weighted mean differences were calculated using random effects meta-analysis. To assess whether subgroups were significantly different, tests for subgroup interaction were used. Subgroup analysis by trials enrolling critically ill versus surgical patients was performed. Twenty-seven randomized controlled trials (10,797 patients) were included. In critical care patients, restrictive transfusion resulted in significantly reduced 30-day mortality compared with liberal transfusion (odds ratio, 0.82; 95% CI, 0.70–0.97). In surgical patients, a restrictive transfusion strategy led to the opposite direction of effect for mortality (odds ratio, 1.31; 95% CI, 0.94–1.82). The subgroup interaction test was significant (p = 0.04), suggesting that the effect of restrictive transfusion on mortality is statistically different for critical care (decreased risk) versus surgical patients (potentially increased risk or no difference). Regarding secondary outcomes, for critically ill patients, a restrictive strategy resulted in reduced risk of stroke/transient ischemic attack, packed RBC exposure, transfusion reactions, and hospital length of stay. In surgical patients, restrictive transfusion resulted in reduced packed RBC exposure.

Conclusions:

The safety of restrictive transfusion strategies likely differs for critically ill patients versus perioperative patients. Further trials investigating transfusion strategies in the perioperative setting are necessary.

Results of an anaemia treatment protocol complementary to blood transfusion in elderly patients with hip fracture

BACKGROUND

Anaemia is a very common condition in elderly patients with hip fracture. The side effects of blood transfusions are well known, and further research on potential alternative therapies is needed.

OBJECTIVES AND DESIGN

A non-controlled descriptive study, conducted on 138 patients admitted for hip fracture, aimed at analysing the effects of an anaemia treatment protocol adjunctive to transfusion, based on the use of supra-physiological doses of intravenous iron and erythropoietin (IS/EPOS). The variables collected were, medical history, physical and cognitive status prior to fracture, as well as the need of blood products, medical complications during admission and their functional outcome at three and six months after the fracture were evaluated. Transfusion rates were compared with a historical control group when the only treatment for acute anaemia was transfusion (2011).

RESULTS

Almost half (63, 48%) of the patients received blood transfusion, with (91,70%) IS/EPOD. Intravenous iron did not reduce the percentage of transfused patients (56% vs. 44%), but it did reduce the number of blood units required (0.7 units less in IS/EPO group). Patients who required transfusion had a longer hospital stay, (1.7 days; 13.2 vs. 11.5; p<0.005). Patients who received IS had better functional recovery assessed with Barthel index and the Functional Ambulation Categories (FAC scale) at 3 and 6 months after the fracture. Patients with malnutrition or subtrochanteric fracture needed more tabletransfusions (p<0.005). Functional recovery at 3 and 6 months after fracture was better in patients who received intravenous iron. Neither blood transfusions nor intravenous iron were associated with infectious complications or increased mortality. The patient series of this study was compared with a group of patients with hip fracture and similar characteristics seen in 2011, before intravenous iron was available, revealing a 17% reduction in blood transfusion needs (p<0.005).

CONCLUSION

The use of intravenous iron in elderly patients with hip fracture may help to reduce the number of blood units needed for the treatment of anaemia, although a causal relationship cannot be established due to not having a control group. Transfusions were associated with longer hospital stay in elderly patients with hip fracture.

Patient Blood Management: Recommendations From the 2018 Frankfurt Consensus Conference

IMPORTANCE

Blood transfusion is one of the most frequently used therapies worldwide and is associated with benefits, risks, and costs.

OBJECTIVE

To develop a set of evidence-based recommendations for patient blood management (PBM) and for research.

EVIDENCE REVIEW

The scientific committee developed 17 Population/Intervention/Comparison/Outcome (PICO) questions for red blood cell (RBC) transfusion in adult patients in 3 areas: preoperative anemia (3 questions), RBC transfusion thresholds (11 questions), and implementation of PBM programs (3 questions). These questions guided the literature search in 4 biomedical databases (MEDLINE, EMBASE, Cochrane Library, Transfusion Evidence Library), searched from inception to January 2018. Meta-analyses were conducted with the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) methodology and the Evidence-to-Decision framework by 3 panels including clinical and scientific experts, nurses, patient representatives, and methodologists, to develop clinical recommendations during a consensus conference in Frankfurt/Main, Germany, in April 2018.

FINDINGS

From 17 607 literature citations associated with the 17 PICO questions, 145 studies, including 63 randomized clinical trials with 23 143 patients and 82 observational studies with more than 4 million patients, were analyzed. For preoperative anemia, 4 clinical and 3 research recommendations were developed, including the strong recommendation to detect and manage anemia sufficiently early before major elective surgery. For RBC transfusion thresholds, 4 clinical and 6 research recommendations were developed, including 2 strong clinical recommendations for critically ill but clinically stable intensive care patients with or without septic shock (recommended threshold for RBC transfusion, hemoglobin concentration <7 g/dL) as well as for patients undergoing cardiac surgery (recommended threshold for RBC transfusion, hemoglobin concentration <7.5 g/dL). For implementation of PBM programs, 2 clinical and 3 research recommendations were developed, including recommendations to implement comprehensive PBM programs and to use electronic decision support systems (both conditional recommendations) to improve appropriate RBC utilization.

CONCLUSIONS AND RELEVANCE

The 2018 PBM International Consensus Conference defined the current status of the PBM evidence base for practice and research purposes and established 10 clinical recommendations and 12 research recommendations for preoperative anemia, RBC transfusion thresholds for adults, and implementation of PBM programs. The relative paucity of strong evidence to answer many of the PICO questions supports the need for additional research and an international consensus for accepted definitions and hemoglobin thresholds, as well as clinically meaningful end points for multicenter trials.

Liberal transfusion strategy to prevent mortality and anaemia-associated, ischaemic events in elderly non-cardiac surgical patients - the study design of the LIBERAL-Trial

Background

Perioperative anaemia leads to impaired oxygen supply with a risk of vital organ ischaemia. In healthy and fit individuals, anaemia can be compensated by several mechanisms. Elderly patients, however, have less compensatory mechanisms because of multiple co-morbidities and age-related decline of functional reserves. The purpose of the study is to evaluate whether elderly surgical patients may benefit from a liberal red blood cell (RBC) transfusion strategy compared to a restrictive transfusion strategy.

Methods

The LIBERAL Trial is a prospective, randomized, multicentre, controlled clinical phase IV trial randomising 2470 elderly (≥ 70 years) patients undergoing intermediate- or high-risk non-cardiac surgery. Registered patients will be randomised only if Haemoglobin (Hb) reaches ≤9 g/dl during surgery or within 3 days after surgery either to the LIBERAL group (transfusion of a single RBC unit when Hb ≤ 9 g/dl with a target range for the post-transfusion Hb level of 9–10.5 g/dl) or the RESTRICTIVE group (transfusion of a single RBC unit when Hb ≤ 7.5 g/dl with a target range for the post-transfusion Hb level of 7.5–9 g/dl). The intervention per patient will be followed until hospital discharge or up to 30 days after surgery, whichever occurs first. The primary efficacy outcome is defined as a composite of all-cause mortality, acute myocardial infarction, acute ischaemic stroke, acute kidney injury (stage III), acute mesenteric ischaemia and acute peripheral vascular ischaemia within 90 days after surgery. Infections requiring iv antibiotics with re-hospitalisation are assessed as important secondary endpoint. The primary endpoint will be analysed by logistic regression adjusting for age, cancer surgery (y/n), type of surgery (intermediate- or high-risk), and incorporating centres as random effect.

Discussion

The LIBERAL-Trial will evaluate whether a liberal transfusion strategy reduces the occurrence of major adverse events after non-cardiac surgery in the geriatric population compared to a restrictive strategy within 90 days after surgery.

Trial registration

ClinicalTrials.gov (identifier: NCT03369210).

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3200-3) contains supplementary material, which is available to authorized users.

Pilot randomized controlled trials in the orthopaedic surgery literature: a systematic review

BACKGROUND

The primary objective of this systematic review is to examine the characteristics of pilot randomized controlled trials (RCTs) in the orthopaedic surgery literature, including the proportion framed as feasibility trials and those that lead to definitive RCTs. This review aim to answer the question of whether pilot RCTs lead to definitive RCTs, whilst investigating the quality, feasibility and overall publication trends of orthopaedic pilot trials.

METHODS

Pilot RCTs in the orthopaedic literature were identified from three electronic databases (EMBASE, MEDLINE, and Pubmed) searched from database inception to January 2018. Search criteria included the evaluation of at least one orthopaedic surgical intervention, research on humans, and publication in English. Two reviewers independently screened the pool of pilot trials, and conducted a search for corresponding definitive trials. Screened pilot RCTs were assessed for feasibility outcomes related to efficiency, cost, and/or timeliness of a large-scale clinical trial involving a surgical intervention. The quality of the pilot and definitive trials were assessed using the Checklist to Evaluate a Report of a Non-Pharmacological Trial (CLEAR NPT).

RESULTS

The initial search for pilot RCTs yielded 3857 titles, of which 49 articles were relevant for this review. 73.5% (36/49) of the orthopaedic pilot RCTs were framed as feasibility trials. Of these, 5 corresponding definitive trials (10.2%) were found, of which four were published and one ongoing. Based on author responses, the lack of a definitive RCT following the pilot trial was attributed to a lack of funding, inadequacies in recruitment, and belief that the pilot RCT sufficiently answered the research question.

CONCLUSIONS

Based on this systematic review, most pilot RCTs were characterized as feasibility trials. However, the majority of published pilot RCTs did not lead to definitive trials. This discrepancy was mainly attributed to poor feasibility (e.g. poor recruitment) and lack of funding for an orthopaedic surgical definitive trial. In recent years this discrepancy may be due to researchers saving on time and cost by rolling their pilot patients into the definitive RCT rather than publish a separate pilot trial.

Clinical trials evaluating red blood cell transfusion thresholds: An updated systematic review and with additional focus on patients with cardiovascular disease

BACKGROUND

Several new trials evaluating transfusion strategies in patients with cardiovascular disease have recently been published, increasing the number of enrolled patients by over 30%. The objective was to evaluate transfusion thresholds in patients with cardiovascular disease.

METHODS

We conducted an updated systematic review of randomized trials that compared patients assigned to maintain a lower (restrictive transfusion strategy) or higher (liberal transfusion strategy) hemoglobin concentration. We focused on new trial data in patients with cardiovascular disease. The primary outcome was 30-day mortality. Specific subgroups were patients undergoing cardiac surgery and with acute myocardial infarction.

RESULTS

A total of 37 trials that enrolled 19,049 patients were appraised. In cardiac surgery, mortality at 30days was comparable between groups (risk ratio 0.99; 95% confidence interval 0.74-1.33). In 2 small trials (n=154) in patients with myocardial infarction, the point estimate for the mortality risk ratio was 3.88 (95% CI, 0.83-18.13) favoring the liberal strategy. Overall, from 26 trials enrolling 15,681 patients, 30-day mortality was not different between restrictive and liberal transfusion strategies (risk ratio 1.0, 95% CI, 0.86-1.16). Overall and in the cardiovascular disease subgroup, there were no significant differences observed across a range of secondary outcomes.

CONCLUSIONS

New trials in patients undergoing cardiac surgery establish that a restrictive transfusion strategy of 7 to 8g/dL is safe and decreased red cell use by 24%. Further research is needed to define the optimal transfusion threshold in patients with acute myocardial infarction.

Effect of blood transfusion on survival after hip fracture surgery

BACKGROUND

Our primary goal was to audit the incidence of erythrocyte blood transfusion (EBT) after hip fracture surgery and study the effects on perioperative complications and early and late mortality.

METHODS

In a retrospective cohort study all patients 65 years old and above treated operatively for an acute hip fracture were included over a 48-month period with a 2-year follow-up period. Postoperative hemoglobin levels were used to investigate at what threshold EBT was used. The relation between EBT and perioperative complications and survival was analyzed with multivariate regression analysis. A propensity score for predicting the chance of receiving an EBT was calculated and used to differentiate between transfusion being a risk factor for mortality and other related confounding risk factors. Mortality was subdivided as in-hospital, 30-day, 1-year and 2-year mortality.

RESULTS

Of the 388 included patients, 41% received a blood transfusion. The postoperative hemoglobin level was the strongest predictor for EBT. Patients who received EBT had a significant longer hospital stay and more postoperative cardiac complications, even after adjustment for confounders. Multivariate analysis for mortality showed that EBT was a significant risk factor for early as well as late mortality, but after adding the propensity score, EBT was no longer associated with increased mortality.

CONCLUSION

There was no effect of EBT on mortality after correction with propensity scoring for predictors of EBT. Transfusion in patients treated operatively for hip fracture should be evenly matched with their cardiovascular risk during the perioperative phase.

Restrictive Versus Liberal Strategy for Red Blood-Cell Transfusion: A Systematic Review and Meta-Analysis in Orthopaedic Patients

BACKGROUND

Current guidelines recommend restrictive criteria for red blood-cell transfusion in most clinical settings. However, patients undergoing orthopaedic surgery may require distinct transfusion criteria since benefits and potential harm often vary considerably based on patient characteristics and surgical procedures. We aimed to assess the efficacy and safety of restrictive transfusion in patients undergoing orthopaedic surgery, especially in important subgroups.

METHODS

Electronic databases were searched to identify randomized controlled trials investigating restrictive (mostly a hemoglobin level of 8.0 g/dL or symptomatic anemia) versus liberal (mostly a hemoglobin level of 10.0 g/dL) transfusion in patients undergoing orthopaedic surgery. For the primary outcome of cardiovascular events, we performed random-effects meta-analyses to synthesize the evidence and to assess the effects in different subgroups according to patient characteristics (with versus without preexisting cardiovascular disease) and surgical procedures (hip fracture surgery versus elective arthroplasty).

RESULTS

Ten trials involving 3,968 participants who underwent hip or knee surgery were included. Mean participant age ranged from 68.7 to 86.9 years. Compared with liberal transfusion, restrictive transfusion increased the risk of cardiovascular events (8 trials; 3,618 participants; relative risk [RR], 1.51; 95% confidence interval [CI], 1.16 to 1.98; p = 0.003; with no heterogeneity across all trials), irrespective of preexisting cardiovascular disease (pinteraction = 0.63). In a subgroup analysis, the increase was observed in patients undergoing hip fracture surgery (RR, 1.51; 95% CI, 1.08 to 2.10; p = 0.02), but did not reach significance in those undergoing elective arthroplasty (RR, 1.53; 95% CI, 0.96 to 2.44; p = 0.07). To minimize the bias caused by variations in transfusion threshold, we conducted an analysis that only included trials using 8.0 g/dL hemoglobin or symptomatic anemia as the threshold for restrictive transfusion and obtained identical results (6 trials; 2,872 participants; RR, 1.51; 95% CI, 1.09 to 2.08; p = 0.01; I = 0%). The 2 arms did not differ with respect to the rates of all infections, 30-day mortality, thromboembolic events, wound infection, pulmonary infection (mainly pneumonia), and cerebrovascular accidents (mainly stroke).

CONCLUSIONS

In patients undergoing orthopaedic surgery, when compared with liberal transfusion, restrictive transfusion increases the risk of cardiovascular events irrespective of preexisting cardiovascular disease. Importantly, the increased risk was observed in patients undergoing hip fracture surgery but did not reach significance in those undergoing elective arthroplasty.

LEVEL OF EVIDENCE

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

A model-based cost-effectiveness analysis of Patient Blood Management

BACKGROUND

Patient blood management (PBM) is a multidisciplinary concept focused on the management of anaemia, minimisation of iatrogenic blood loss and rational use of allogeneic blood products. The aims of this study were: (i) to analyse post-operative outcome in patients with liberal vs restrictive exposure to allogeneic blood products and (ii) to evaluate the cost-effectiveness of PBM in patients undergoing surgery.

MATERIALS AND METHODS

A systematic literature review and meta-analysis were performed to compare post-operative complications in predominantly non-transfused patients (restrictive transfusion group) and patients who received one to three units of red blood cells (liberal transfusion group). Outcome measures included sepsis with/without pneumonia, acute renal failure, acute myocardial infarction and acute stroke. In a second step, a health economic model was developed to calculate cost-effectiveness of PBM (PBM-arm vs control-arm) for simulated cohorts of 10,000 cardiac and non-cardiac surgical patients based on the results of the meta-analysis and costs.

RESULTS

Out of 478 search results, 22 studies were analysed in the meta-analysis. The pooled relative risk of any complication in the restrictive transfusion group was 0.43 for non-cardiac and 0.34 for cardiac surgical patients. In the simulation model, PBM was related to reduced complications (1,768 vs 1,245) and complication-related deaths (411 vs 304) compared to standard care. PBM-related costs of therapy exceeded costs of the control arm by € 150 per patient. However, total costs, including hospitalisation, were higher in the control-arm for both non-cardiac (€ 2,885.11) and cardiac surgery patients (€ 1,760.69). The incremental cost-effectiveness ratio including hospitalisation showed savings of € 30,458 (non-cardiac and cardiac surgery patients) for preventing one complication and € 128,023 (non-cardiac and cardiac surgery patients) for prevention of one complication-related death in the PBM-arm.

DISCUSSION

Our results indicate that PBM may be associated with fewer adverse clinical outcomes compared to control management and may, thereby, be cost-effective.

Hemolysis in In-Date RBC Concentrates

OBJECTIVES

Hemolysis is one of the most prominent changes that occur during the liquid storage of RBCs in additive solution (AS), but most studies have measured hemolysis only on day 42.

METHODS

Prestorage leukoreduced RBCs in AS-1 and AS-3 were studied, one group on day 42 and a second group between day 0 and day 40. Each product was sampled for direct measurement of supernatant hemoglobin and hematocrit.

RESULTS

Ninety day 42 and 218 day 7 to day 39 RBCs showed a mean ± SD supernatant hemoglobin of 75 ± 100 vs 25.5 ± 16 mg/dL respectively (P < .01). Supernatant hemoglobin correlated weakly with storage age (r = 0.2, P < .01) but more strongly with hematocrit (r = 0.4, P < .01).

CONCLUSIONS

There are minimal differences in supernatant hemoglobin until the final days of liquid storage when some high hematocrit RBCs show excessive hemolysis.

Transfusion Thresholds for Major Orthopedic Surgery: A Systematic Review and Meta-analysis

BACKGROUND

More than a million surgeries are performed annually in the United States for hip or knee arthroplasty or hip fracture stabilization. One-fifth of these patients have blood transfusions during their hospital stay. Increases in transfusion rates have caused concern about increased adverse events from unnecessary transfusions.

METHODS

We systematically reviewed randomized trials examining the effect of restrictive vs liberal transfusion thresholds on patients having major orthopedic surgery. Study results were meta-analyzed with a random-effects model and heterogeneity was tested with the I² statistic. Study risk of bias was assessed using a modified Jadad scale and evidence strength was measured using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system.

RESULTS

A total of 504 published articles were screened, and 15 met inclusion criteria. The articles described 9 randomized trials, most comparing transfusion thresholds of 8 vs 10 g/dL hemoglobin. All involved hip or knee arthroplasty and/or hip fracture patients. Moderate-strength evidence suggested a reduction in need for transfusion (relative risk, 0.53; 95% confidence interval [CI], 0.39-0.71; I² = 95%) and mean number of units transfused (-0.95 units, 95% CI, -1.48 to -0.41, I² = 98%). There was a possible reduction in overall infections with more restrictive transfusion thresholds, although the result was not statistically significant (relative risk, 0.71; 95% CI, 0.47-1.06; I² = 54%). Moderate-strength evidence suggested no differences in other clinical outcomes between the groups. Limitations included incomplete blinding, inconsistency, and imprecision.

CONCLUSION

Moderate-strength evidence suggests that restrictive transfusion practices reduce utilization of transfusions and may decrease infections without increasing adverse outcomes in major orthopedic surgery.

Restrictive versus liberal transfusion strategies for red blood cell transfusion after hip or knee surgery: A systematic review and meta-analysis

BACKGROUND

Red blood cell (RBC) transfusions are commonly used in surgical patients, but accompanied by many risks such as metabolic derangement, and allergic and febrile reactions. Indications for transfusion in patients after hip or knee surgery have not been definitively evaluated and remain controversial. We performed a meta-analysis to compare the benefits and harms of restrictive versus liberal transfusion strategies in patients after hip or knee surgery.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were searched for relevant studies through September 2015. The main clinical outcomes reported in randomized controlled trials (RCTs) included 30-day mortality, infection rate, cardiogenic complications, and length of hospital stay. The meta-analysis program of the Cochrane Collaboration (RevMan version 5.3.0) was used for data analysis. Statistical heterogeneity was assessed by both Cochran chi-squared test (Q test) and I test. Begg and Egger test were used to assess potential publication bias.

RESULTS

We identified 10 eligible RCTs, involving 3788 patients in total. In patients undergoing hip or knee surgery, we found no differences in mortality, or the incidence rates of pneumonia, wound infection, myocardial infarction, or congestive heart failure, between restrictive and liberal thresholds for RBC transfusion (P > .05).

CONCLUSION

Restrictive transfusion has no advantage over the liberal strategy. However, considerably less patients received blood transfusion via the restrictive strategy than with the liberal counterpart. Due to variations in the included studies, additional larger scale and well-designed studies are required to validate these conclusions.

Limited Blood Transfusions Are Safe in Orthopaedic Trauma Patients

OBJECTIVES

Controversy exists over association of blood transfusions with complications. The purpose was to assess effects of limited transfusions on complication rates and hospital course.

SETTING

Level 1 trauma center.

PATIENTS AND METHODS

Three hundred seventy-one consecutive patients with Injury Severity Score ≥16 underwent fixation of fractures of spine (n = 111), pelvis (n = 72), acetabulum (n = 57), and/or femur (n = 179). Those receiving >3 units of packed red blood cell were excluded.

MAIN OUTCOME MEASUREMENTS

Fracture type, associated injuries, treatment details, ventilation time, complications, and hospital stay were prospectively recorded.

RESULTS

Ninety-eight patients with 107 fractures received limited transfusion, and 119 patients with 123 fractures were not transfused. The groups did not differ in age, fracture types, time to fixation, or associated injuries. Lowest hematocrit was lower in the transfused group (22.8 vs. 30.0, P < 0.0001). Surgical duration (3:23 vs. 2:28) and estimated blood loss (462 vs. 211 mL) were higher in transfused patients (all P < 0.003). Pulmonary complications occurred in 12% of transfused and 4% of nontransfused, (P = 0.10). Mean days of mechanical ventilation (2.51 vs. 0.45), intensive care unit days (4.5 vs. 1.5) and total hospital stay (8.8 vs. 5.7) were higher in transfused patients (all P ≤ 0.006). After multivariate analysis, limited transfusion was associated with increased hospital and intensive care unit stays and mechanical ventilation time, but not with complications.

CONCLUSIONS

Patients receiving ≤3 units of packed red blood cell had lower hematocrit and greater surgical burden, but no difference in complications versus the nontransfused group. Limited blood transfusions are likely safe, excepting a possible association with longer mechanical ventilation times and hospital stays.

LEVEL OF EVIDENCE

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

Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion

BACKGROUND

There is considerable uncertainty regarding the optimal haemoglobin threshold for the use of red blood cell (RBC) transfusions in anaemic patients. Blood is a scarce resource, and in some countries, transfusions are less safe than others because of a lack of testing for viral pathogens. Therefore, reducing the number and volume of transfusions would benefit patients.

OBJECTIVES

The aim of this review was to compare 30-day mortality and other clinical outcomes in participants randomized to restrictive versus liberal red blood cell (RBC) transfusion thresholds (triggers) for all conditions. The restrictive transfusion threshold uses a lower haemoglobin level to trigger transfusion (most commonly 7 g/dL or 8 g/dL), and the liberal transfusion threshold uses a higher haemoglobin level to trigger transfusion (most commonly 9 g/dL to 10 g/dL).

SEARCH METHODS

We identified trials by searching CENTRAL (2016, Issue 4), MEDLINE (1946 to May 2016), Embase (1974 to May 2016), the Transfusion Evidence Library (1950 to May 2016), the Web of Science Conference Proceedings Citation Index (1990 to May 2016), and ongoing trial registries (27 May 2016). We also checked reference lists of other published reviews and relevant papers to identify any additional trials.

SELECTION CRITERIA

We included randomized trials where intervention groups were assigned on the basis of a clear transfusion 'trigger', described as a haemoglobin (Hb) or haematocrit (Hct) level below which a red blood cell (RBC) transfusion was to be administered.

DATA COLLECTION AND ANALYSIS

We pooled risk ratios of clinical outcomes across trials using a random-effects model. Two people extracted the data and assessed the risk of bias. We conducted predefined analyses by clinical subgroups. We defined participants randomly allocated to the lower transfusion threshold as 'restrictive transfusion' and to the higher transfusion threshold as 'liberal transfusion'.

MAIN RESULTS

A total of 31 trials, involving 12,587 participants, across a range of clinical specialities (e.g. surgery, critical care) met the eligibility criteria. The trial interventions were split fairly equally with regard to the haemoglobin concentration used to define the restrictive transfusion group. About half of them used a 7 g/dL threshold, and the other half used a restrictive transfusion threshold of 8 g/dL to 9 g/dL. The trials were generally at low risk of bias .Some items of methodological quality were unclear, including definitions and blinding for secondary outcomes.Restrictive transfusion strategies reduced the risk of receiving a RBC transfusion by 43% across a broad range of clinical specialties (risk ratio (RR) 0.57, 95% confidence interval (CI) 0.49 to 0.65; 12,587 participants, 31 trials; high-quality evidence), with a large amount of heterogeneity between trials (I² = 97%). Overall, restrictive transfusion strategies did not increase or decrease the risk of 30-day mortality compared with liberal transfusion strategies (RR 0.97, 95% CI 0.81 to 1.16, I² = 37%; N = 10,537; 23 trials; moderate-quality evidence) or any of the other outcomes assessed (i.e. cardiac events (low-quality evidence), myocardial infarction, stroke, thromboembolism (high-quality evidence)). Liberal transfusion did not affect the risk of infection (pneumonia, wound, or bacteraemia).

AUTHORS' CONCLUSIONS

Transfusing at a restrictive haemoglobin concentration of between 7 g/dL to 8 g/dL decreased the proportion of participants exposed to RBC transfusion by 43% across a broad range of clinical specialities. There was no evidence that a restrictive transfusion strategy impacts 30-day mortality or morbidity (i.e. mortality at other points, cardiac events, myocardial infarction, stroke, pneumonia, thromboembolism, infection) compared with a liberal transfusion strategy. There were insufficient data to inform the safety of transfusion policies in certain clinical subgroups, including acute coronary syndrome, myocardial infarction, neurological injury/traumatic brain injury, acute neurological disorders, stroke, thrombocytopenia, cancer, haematological malignancies, and bone marrow failure. The findings provide good evidence that transfusions with allogeneic RBCs can be avoided in most patients with haemoglobin thresholds above 7 g/dL to 8 g/dL.

Restrictive versus Liberal Transfusion Strategy in the Perioperative and Acute Care Settings

Background

Blood transfusions are associated with morbidity and mortality. However, restrictive thresholds could harm patients less able to tolerate anemia. Using a context-specific approach (according to patient characteristics and clinical settings), the authors conducted a systematic review to quantify the effects of transfusion strategies.

Methods

The authors searched MEDLINE, EMBASE, CENTRAL, and grey literature sources to November 2015 for randomized controlled trials comparing restrictive versus liberal transfusion strategies applied more than 24 h in adult surgical or critically ill patients. Data were independently extracted. Risk ratios were calculated for 30-day complications, defined as inadequate oxygen supply (myocardial, cerebral, renal, mesenteric, and peripheral ischemic injury; arrhythmia; and unstable angina), mortality, composite of both, and infections. Statistical combination followed a context-specific approach. Additional analyses explored transfusion protocol heterogeneity and cointerventions effects.

Results

Thirty-one trials were regrouped into five context-specific risk strata. In patients undergoing cardiac/vascular procedures, restrictive strategies seemed to increase the risk of events reflecting inadequate oxygen supply (risk ratio [RR], 1.09; 95% CI, 0.97 to 1.22), mortality (RR, 1.39; 95% CI, 0.95 to 2.04), and composite events (RR, 1.12; 95% CI, 1.01 to 1.24—3322, 3245, and 3322 patients, respectively). Similar results were found in elderly orthopedic patients (inadequate oxygen supply: RR, 1.41; 95% CI, 1.03 to 1.92; mortality: RR, 1.09; 95% CI, 0.80 to 1.49; composite outcome: RR, 1.24; 95% CI, 1.00 to 1.54—3465, 3546, and 3749 patients, respectively), but not in critically ill patients. No difference was found for infections, although a protective effect may exist. Risk estimates varied with successful/unsuccessful transfusion protocol implementation.

Conclusions

Restrictive transfusion strategies should be applied with caution in high-risk patients undergoing major surgery.

Transfusion Thresholds, Quality of Life, and Current Approaches in Myelodysplastic Syndromes

Hemoglobin thresholds and triggers for blood transfusions have changed over the years moving from a higher to a lower level. This review article summarizes the current evidence of transfusion thresholds in the hospitalized as well as in the outpatient setting and particularly in myelodysplasia. Fatigue is the main reported symptom in this group of patients and current clinical trials are looking for a more liberal approach of red cell transfusion and the effect on quality of life as opposed to the restrictive strategy used in the critical care setting. Practical considerations, the cost effectiveness of this strategy in addition to the possible complications, and the use of quality of life questionnaires have also been reviewed.

Effect of restrictive versus liberal transfusion strategies on outcomes in patients with cardiovascular disease in a non-cardiac surgery setting: systematic review and meta-analysis

OBJECTIVE

To compare patient outcomes of restrictive versus liberal blood transfusion strategies in patients with cardiovascular disease not undergoing cardiac surgery.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Randomised controlled trials involving a threshold for red blood cell transfusion in hospital. We searched (to 2 November 2015) CENTRAL, Medline, Embase, CINAHL, PubMed, LILACS, NHSBT Transfusion Evidence Library, ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, ISRCTN Register, and EU Clinical Trials Register. Authors were contacted for data whenever possible.

TRIAL SELECTION

Published and unpublished randomised controlled trials comparing a restrictive with liberal transfusion threshold and that included patients with cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Data extraction was completed in duplicate. Risk of bias was assessed using Cochrane methods. Relative risk ratios with 95% confidence intervals were presented in all meta-analyses. Mantel-Haenszel random effects models were used to pool risk ratios.

MAIN OUTCOME MEASURES

30 day mortality, and cardiovascular events.

RESULTS

41 trials were identified; of these, seven included data on patients with cardiovascular disease. Data from a further four trials enrolling patients with cardiovascular disease were obtained from the authors. In total, 11 trials enrolling patients with cardiovascular disease (n=3033) were included for meta-analysis (restrictive transfusion, n=1514 patients; liberal transfusion, n=1519). The pooled risk ratio for the association between transfusion thresholds and 30 day mortality was 1.15 (95% confidence interval 0.88 to 1.50, P=0.50), with little heterogeneity (I(2)=14%). The risk of acute coronary syndrome in patients managed with restrictive compared with liberal transfusion was increased (nine trials; risk ratio 1.78, 95% confidence interval 1.18 to 2.70, P=0.01, I(2)=0%).

CONCLUSIONS

The results show that it may not be safe to use a restrictive transfusion threshold of less than 80 g/L in patients with ongoing acute coronary syndrome or chronic cardiovascular disease. Effects on mortality and other outcomes are uncertain. These data support the use of a more liberal transfusion threshold (>80 g/L) for patients with both acute and chronic cardiovascular disease until adequately powered high quality randomised trials have been undertaken in patients with cardiovascular disease.

REGISTRATION

PROSPERO CRD42014014251.

Perioperative fluid volume optimization following proximal femoral fracture

BACKGROUND

Proximal femoral fracture (PFF) is a common orthopaedic emergency that affects mainly elderly people at high risk of complications. Advanced methods for managing fluid therapy during treatment for PFF are available, but their role in reducing risk is unclear.

OBJECTIVES

To compare the safety and effectiveness of the following methods of perioperative fluid optimization in adult participants undergoing surgical repair of hip fracture: advanced invasive haemodynamic monitoring, such as transoesophageal Doppler and pulse contour analysis; a protocol using standard measures, such as blood pressure, urine output and central venous pressure; and usual care.Comparisons of fluid types (e.g. crystalloid vs colloid) and other methods of optimizing oxygen delivery, such as blood product therapies and pharmacological treatment with inotropes and vasoactive drugs, are considered in other reviews.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 9); MEDLINE (October 2012 to September 2015); and EMBASE (October 2012 to September 2015) without language restrictions. We ran forward and backward citation searches on identified trials. We searched ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform for unpublished trials. This is an updated version of a review published originally in 2004 and updated first in 2013 and again in 2015. Original searches were performed in October 2003 and October 2012.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) in adult participants undergoing surgical treatment for PFF that compared any two of advanced haemodynamic monitoring, protocols using standard measures or usual care, irrespective of blinding, language or publication status.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the impact of fluid optimization interventions on outcomes of mortality, length of hospital stay, time to medical fitness, whether participants were able to return to pre-fracture accommodation at six months, participant mobility at six months and adverse events in-hospital. We pooled data using risk ratio (RR) or mean difference (MD) for dichotomous or continuous data, respectively, on the basis of random-effects models.

MAIN RESULTS

We included in this updated review five RCTs with a total of 403 participants, and we added two new trials identified during the 2015 search. One of the included studies was found to have a high risk of bias; no trial featured all pre-specified outcomes. We found two trials for which data are awaited for classification and one ongoing trial.Three studies compared advanced haemodynamic monitoring with a protocol using standard measures; three compared advanced haemodynamic monitoring with usual care; and one compared a protocol using standard measures with usual care. Meta-analyses for the two advanced haemodynamic monitoring comparisons are consistent with both increased and decreased risk of mortality (RR Mantel-Haenszel (M-H) random-effects 0.41, 95% confidence interval (CI) 0.14 to 1.20; 280 participants; RR M-H random-effects 0.45, 95% CI 0.07 to 2.95; 213 participants, respectively). The study comparing a protocol with usual care found no difference between groups for this outcome.Three studies comparing advanced haemodynamic monitoring with usual care reported data for length of stay and time to medical fitness. There was no statistically significant difference between groups for these outcomes in the two studies that we were able to combine (MD IV fixed 0.63, 95% CI -1.70 to 2.96); MD IV fixed 0.01, 95% CI -1.74 to 1.71, respectively) and no statistically significant difference in the third study. One study reported reduced time to medical fitness when comparing advanced haemodynamic monitoring with a protocol, and when comparing protocol monitoring with usual care.The number of participants with one or more complications showed no statistically significant differences in each of the two advanced haemodynamic monitoring comparisons (RR M-H random-effects 0.83, 95% CI 0.59 to 1.17; 280 participants; RR M-H random-effects 0.72, 95% CI 0.40 to 1.31; 173 participants, respectively), nor any differences in the protocol and usual care comparison.Only one study reported the number of participants able to return to normal accommodation after discharge with no statistically significant difference between groups.There were few studies with a small number of participants, and by using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation Working Group) approach, we judged the quality of the outcome evidence as low. We had included one study with a high risk of bias, but upon applying GRADE, we downgraded the quality of this outcome evidence to very low.

AUTHORS' CONCLUSIONS

Five studies including a total of 403 participants provided no evidence that fluid optimization strategies improve outcomes for participants undergoing surgery for PFF. Further research powered to test some of these outcomes is ongoing.

Hemoglobin thresholds for transfusion in pediatric patients at a large academic health center

BACKGROUND

Although prior studies support the use of a hemoglobin (Hb) transfusion trigger of 7 to 8 g/dL for most hospitalized adults, there are few studies in pediatric populations. We therefore investigated transfusion practices and Hb triggers in hospitalized children.

STUDY DESIGN AND METHODS

We performed a historical cohort study comparing transfusion practices in hospitalized children by service within a single academic institution. Blood utilization data from transfused patients (n = 3370) were obtained from electronic records over 4 years. Hb triggers and posttransfusion Hb levels were defined as the lowest and last Hb measured during hospital stay, respectively, in transfused patients. The mean and percentile distribution for Hb triggers were compared to the evidence-based restrictive transfusion threshold of 7 g/dL.

RESULTS

Mean Hb triggers were above the restrictive trigger (7 g/dL) for eight of 12 pediatric services. Among all of the services, there were significant differences between the mean Hb triggers (>2.5 g/dL, p<0.0001) and between the posttransfusion Hb levels (>3 g/dL, p < 0.0001). The variation between the 10th and 90th percentiles for triggers (up to 4 g/dL, p < 0.0001) and posttransfusion Hb levels (up to 6 g/dL, p < 0.0001) were significant. Depending on the service, between 25 and 90% of transfused patients had Hb triggers higher than the restrictive range.

CONCLUSIONS

Red blood cell (RBC) transfusion therapy varies significantly in hospitalized children with mean Hb triggers above a restrictive threshold for most services. Our findings suggest that transfusions may be overused and that implementing a restrictive transfusion strategy could decrease the use of RBC transfusions, thereby reducing the associated risks and costs.

Restrictive blood transfusion strategies and associated infection in orthopedic patients: a meta-analysis of 8 randomized controlled trials

This study sought to evaluate whether restrictive blood transfusion strategies are associated with a risk of infection in orthopedic patients by conducting a meta-analysis of randomized controlled trials (RCTs). RCTs with restrictive versus liberal red blood cell (RBC) transfusion strategies were identified by searching Medline, Embase, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews from their inception to December 2014. Eight RCTs with infections as outcomes were included in the final analysis. According to the Jadad scale, all studies were considered to be of high quality. The pooled risk ratio [RR] for the association between transfusion strategy and infection was 0.65 (95% CI, 0.47-0.91; p = 0.012), and the number of patients needed to treat to avoid an infection using a restrictive transfusion strategy was 62. No heterogeneity was observed. The sensitivity analysis indicated unstable results, and no significant publication bias was observed. This meta-analysis of RCTs demonstrates that restrictive transfusion strategies in orthopedic patients result in a significant reduction in infections compared with more liberal strategies.

A systematic review of pre-operative anaemia and blood transfusion in patients with fractured hips

We systematically reviewed the observational associations of anaemia with outcomes and the effects of interventions to increase haemoglobin concentrations following hip fracture in older people. Anaemia on hospital admission was associated with increased mortality, relative risk 1.64 (95% CI 1.47-1.82), p < 0.0001. After adjustment for co-morbidities, the association of anaemia with increased mortality remained in four of eight observational studies. There was no association of postoperative transfusion with mortality after adjusting for covariates. Transfusion at 80 g.l(-1) vs 100 g.l(-1) increased acute myocardial infarction, relative risk 1.67 (95% CI 1.01-2.77), p = 0.05. Transfusion threshold was not associated with differences in other outcomes. There were insufficient high-quality studies to inform pre-operative blood transfusion or the use of peri-operative iron or erythropoietin. Studies for most interventions recruited too few participants to determine effects on infections, mortality or function.

Red blood cell transfusion for people undergoing hip fracture surgery

BACKGROUND

The incidence of hip fracture is increasing and it is more common with increasing age. Surgery is used for almost all hip fractures. Blood loss occurs as a consequence of both the fracture and the surgery and thus red blood cell transfusion is frequently used. However, red blood cell transfusion is not without risks. Therefore, it is important to identify the evidence for the effective and safe use of red blood cell transfusion in people with hip fracture.

OBJECTIVES

To assess the effects (benefits and harms) of red blood cell transfusion in people undergoing surgery for hip fracture.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (31 October 2014), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2014, Issue 10), MEDLINE (January 1946 to 20 November 2014), EMBASE (January 1974 to 20 November 2014), CINAHL (January 1982 to 20 November 2014), British Nursing Index Database (January 1992 to 20 November 2014), the Systematic Review Initiative's Transfusion Evidence Library, PubMed for e-publications, various other databases and ongoing trial registers.

SELECTION CRITERIA

Randomised controlled trials comparing red blood cell transfusion versus no transfusion or an alternative to transfusion, different transfusion protocols or different transfusion thresholds in people undergoing surgery for hip fracture.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed each study's risk of bias and extracted data using a study-specific form. We pooled data where there was homogeneity in the trial comparisons and the timing of outcome measurement. We used GRADE criteria to assess the quality (low, moderate or high) of the evidence for each outcome.

MAIN RESULTS

We included six trials (2722 participants): all compared two thresholds for red blood cell transfusion: a 'liberal' strategy to maintain a haemoglobin concentration of usually 10 g/dL versus a more 'restrictive' strategy based on symptoms of anaemia or a lower haemoglobin concentration, usually 8 g/dL. The exact nature of the transfusion interventions, types of surgery and participants varied between trials. The mean age of participants ranged from 81 to 87 years and approximately 24% of participants were men. The largest trial enrolled 2016 participants, over 60% of whom had a history of cardiovascular disease. The percentage of participants receiving a red blood cell transfusion ranged from 74% to 100% in the liberal transfusion threshold group and from 11% to 45% in the restrictive transfusion threshold group. There were no results available for the smallest trial (18 participants). All studies were at some risk of bias, in particular performance bias relating to the absence of blinding of personnel. We judged the evidence for all outcomes, except myocardial infarction, was low quality reflecting risk of bias primarily from imbalances in protocol violations in the largest trial and imprecision, often because of insufficient events. Thus, further research is likely to have an important impact on these results.There was no evidence of a difference between a liberal versus restricted threshold transfusion in mortality, at 30 days post hip fracture surgery (risk ratio (RR) 0.92, 95% confidence interval (CI) 0.67 to 1.26; five trials; 2683 participants; low quality evidence) or at 60 days post surgery (RR 1.08, 95% CI 0.80 to 1.44; three trials; 2283 participants; low quality evidence). Assuming an illustrative baseline risk of 50 deaths per 1000 participants in the restricted threshold group at 30 days, these data equate to four fewer (95% CI 17 fewer to 14 more) deaths per 1000 in the liberal threshold group at 30 days.There was no evidence of a difference between a liberal versus restricted threshold transfusion in functional recovery at 60 days, assessed in terms of the inability to walk 10 feet (3 m) without human assistance (RR 1.00, 95% CI 0.87 to 1.15; two trials; 2083 participants; low quality evidence).There was low quality evidence of no difference between the transfusion thresholds in postoperative morbidity for the following complications: thromboembolism (RR 1.15 favouring a restrictive threshold, 95% CI 0.56 to 2.37; four trials; 2416 participants), stroke (RR 2.40 favouring a restrictive threshold, 95% CI 0.85 to 6.79; four trials; 2416 participants), wound infection (RR 1.61 favouring a restrictive threshold, 95% CI 0.77 to 3.35; three trials; 2332 participants), respiratory infection (pneumonia) (RR 1.35 favouring a restrictive threshold, 95% CI 0.95 to 1.92; four trials; 2416 participants) and new diagnosis of congestive heart failure (RR 0.77 favouring a liberal threshold, 95% CI 0.48 to 1.23; three trials; 2332 participants). There was very low quality evidence of a lower risk of myocardial infarction in the liberal compared with the restrictive transfusion threshold group (RR 0.59, 95% CI 0.36 to 0.96; three trials; 2217 participants). Assuming an illustrative baseline risk of myocardial infarction of 24 per 1000 participants in the restricted threshold group, this result was compatible with between one and 15 fewer myocardial infarctions in the liberal threshold group.

AUTHORS' CONCLUSIONS

We found low quality evidence of no difference in mortality, functional recovery or postoperative morbidity between 'liberal' versus 'restrictive' thresholds for red blood cell transfusion in people undergoing surgery for hip fracture. Although further research may change the estimates of effect, the currently available evidence does not support the use of liberal red blood cell transfusion thresholds based on a 10 g/dL haemoglobin trigger in preference to more restrictive transfusion thresholds based on lower haemoglobin levels or symptoms of anaemia in these people. Future research needs to address the effectiveness of red blood cell transfusions at different time points in the surgical pathway, whether pre-operative, peri-operative or postoperative. In particular, such research would need to consider people who are symptomatic or haemodynamically unstable who were excluded from most of these trials.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

Restrictive versus liberal transfusion strategy for red blood cell transfusion: systematic review of randomised trials with meta-analysis and trial sequential analysis

OBJECTIVE

To compare the benefit and harm of restrictive versus liberal transfusion strategies to guide red blood cell transfusions.

DESIGN

Systematic review with meta-analyses and trial sequential analyses of randomised clinical trials.

DATA SOURCES

Cochrane central register of controlled trials, SilverPlatter Medline (1950 to date), SilverPlatter Embase (1980 to date), and Science Citation Index Expanded (1900 to present). Reference lists of identified trials and other systematic reviews were assessed, and authors and experts in transfusion were contacted to identify additional trials.

TRIAL SELECTION

Published and unpublished randomised clinical trials that evaluated a restrictive compared with a liberal transfusion strategy in adults or children, irrespective of language, blinding procedure, publication status, or sample size.

DATA EXTRACTION

Two authors independently screened titles and abstracts of trials identified, and relevant trials were evaluated in full text for eligibility. Two reviewers then independently extracted data on methods, interventions, outcomes, and risk of bias from included trials. random effects models were used to estimate risk ratios and mean differences with 95% confidence intervals.

RESULTS

31 trials totalling 9813 randomised patients were included. The proportion of patients receiving red blood cells (relative risk 0.54, 95% confidence interval 0.47 to 0.63, 8923 patients, 24 trials) and the number of red blood cell units transfused (mean difference -1.43, 95% confidence interval -2.01 to -0.86) were lower with the restrictive compared with liberal transfusion strategies. Restrictive compared with liberal transfusion strategies were not associated with risk of death (0.86, 0.74 to 1.01, 5707 patients, nine lower risk of bias trials), overall morbidity (0.98, 0.85 to 1.12, 4517 patients, six lower risk of bias trials), or fatal or non-fatal myocardial infarction (1.28, 0.66 to 2.49, 4730 patients, seven lower risk of bias trials). Results were not affected by the inclusion of trials with unclear or high risk of bias. Using trial sequential analyses on mortality and myocardial infarction, the required information size was not reached, but a 15% relative risk reduction or increase in overall morbidity with restrictive transfusion strategies could be excluded.

CONCLUSIONS

Compared with liberal strategies, restrictive transfusion strategies were associated with a reduction in the number of red blood cell units transfused and number of patients being transfused, but mortality, overall morbidity, and myocardial infarction seemed to be unaltered. Restrictive transfusion strategies are safe in most clinical settings. Liberal transfusion strategies have not been shown to convey any benefit to patients.

TRIAL REGISTRATION

PROSPERO CRD42013004272.

Predicting red blood cell transfusion in hospitalized patients: role of hemoglobin level, comorbidities, and illness severity

Background

Randomized controlled trial evidence supports a restrictive strategy of red blood cell (RBC) transfusion, but significant variation in clinical transfusion practice persists. Patient characteristics other than hemoglobin levels may influence the decision to transfuse RBCs and explain some of this variation. Our objective was to evaluate the role of patient comorbidities and severity of illness in predicting inpatient red blood cell transfusion events.

Methods

We developed a predictive model of inpatient RBC transfusion using comprehensive electronic medical record (EMR) data from 21 hospitals over a four year period (2008-2011). Using a retrospective cohort study design, we modeled predictors of transfusion events within 24 hours of hospital admission and throughout the entire hospitalization. Model predictors included administrative data (age, sex, comorbid conditions, admission type, and admission diagnosis), admission hemoglobin, severity of illness, prior inpatient RBC transfusion, admission ward, and hospital.

Results

The study cohort included 275,874 patients who experienced 444,969 hospitalizations. The 24 hour and overall inpatient RBC transfusion rates were 7.2% and 13.9%, respectively. A predictive model for transfusion within 24 hours of hospital admission had a C-statistic of 0.928 and pseudo-R2 of 0.542; corresponding values for the model examining transfusion through the entire hospitalization were 0.872 and 0.437. Inclusion of the admission hemoglobin resulted in the greatest improvement in model performance relative to patient comorbidities and severity of illness.

Conclusions

Data from electronic medical records at the time of admission predicts with very high likelihood the incidence of red blood transfusion events in the first 24 hours and throughout hospitalization. Patient comorbidities and severity of illness on admission play a small role in predicting the likelihood of RBC transfusion relative to the admission hemoglobin.

Health care-associated infection after red blood cell transfusion: a systematic review and meta-analysis

IMPORTANCE

The association between red blood cell (RBC) transfusion strategies and health care-associated infection is not fully understood.

OBJECTIVE

To evaluate whether RBC transfusion thresholds are associated with the risk of infection and whether risk is independent of leukocyte reduction.

DATA SOURCES

MEDLINE, EMBASE, Web of Science Core Collection, Cochrane Central Register of Controlled Trials, Cochrane Database of Sytematic Reviews, ClinicalTrials.gov, International Clinical Trials Registry, and the International Standard Randomized Controlled Trial Number register were searched through January 22, 2014.

STUDY SELECTION

Randomized clinical trials with restrictive vs liberal RBC transfusion strategies.

DATA EXTRACTION AND SYNTHESIS

Twenty-one randomized trials with 8735 patients met eligibility criteria, of which 18 trials (n = 7593 patients) contained sufficient information for meta-analyses. DerSimonian and Laird random-effects models were used to report pooled risk ratios. Absolute risks of infection were calculated using the profile likelihood random-effects method.

MAIN OUTCOMES AND MEASURES

Incidence of health care-associated infection such as pneumonia, mediastinitis, wound infection, and sepsis.

RESULTS

The pooled risk of all serious infections was 11.8% (95% CI, 7.0%-16.7%) in the restrictive group and 16.9% (95% CI, 8.9%-25.4%) in the liberal group. The risk ratio (RR) for the association between transfusion strategies and serious infection was 0.82 (95% CI, 0.72-0.95) with little heterogeneity (I2 = 0%; τ2 <.0001). The number needed to treat (NNT) with restrictive strategies to prevent serious infection was 38 (95% CI, 24-122). The risk of infection remained reduced with a restrictive strategy, even with leukocyte reduction (RR, 0.80 [95% CI, 0.67-0.95]). For trials with a restrictive hemoglobin threshold of <7.0 g/dL, the RR was 0.82 (95% CI, 0.70-0.97) with NNT of 20 (95% CI, 12-133). With stratification by patient type, the RR was 0.70 (95% CI, 0.54-0.91) in patients undergoing orthopedic surgery and 0.51 (95% CI, 0.28-0.95) in patients presenting with sepsis. There were no significant differences in the incidence of infection by RBC threshold for patients with cardiac disease, the critically ill, those with acute upper gastrointestinal bleeding, or for infants with low birth weight.

CONCLUSIONS AND RELEVANCE

Among hospitalized patients, a restrictive RBC transfusion strategy was associated with a reduced risk of health care-associated infection compared with a liberal transfusion strategy. Implementing restrictive strategies may have the potential to lower the incidence of health care-associated infection.

Impact of more restrictive blood transfusion strategies on clinical outcomes: a meta-analysis and systematic review

BACKGROUND

There is accumulating evidence that restricting blood transfusions improves outcomes, with newer trials showing greater benefit from more restrictive strategies. We systematically evaluated the impact of various transfusion triggers on clinical outcomes.

METHODS

The MEDLINE database was searched from 1966 to April 2013 to find randomized trials evaluating a restrictive hemoglobin transfusion trigger of <7 g/dL, compared with a more liberal trigger. Two investigators independently extracted data from the trials. Outcomes evaluated included mortality, acute coronary syndrome, pulmonary edema, infections, rebleeding, number of patients transfused, and units of blood transfused per patient. Extracted data also included information on study setting, design, participant characteristics, and risk for bias of the included trials. A secondary analysis evaluated trials using less restrictive transfusion triggers, and a systematic review of observational studies evaluated more restrictive triggers.

RESULTS

In the primary analysis, pooled results from 3 trials with 2364 participants showed that a restrictive hemoglobin transfusion trigger of <7 g/dL resulted in reduced in-hospital mortality (risk ratio [RR], 0.74; confidence interval [CI], 0.60-0.92), total mortality (RR, 0.80; CI, 0.65-0.98), rebleeding (RR, 0.64; CI, 0.45-0.90), acute coronary syndrome (RR, 0.44; CI, 0.22-0.89), pulmonary edema (RR, 0.48; CI, 0.33-0.72), and bacterial infections (RR, 0.86; CI, 0.73-1.00), compared with a more liberal strategy. The number needed to treat with a restrictive strategy to prevent 1 death was 33. Pooled data from randomized trials with less restrictive transfusion strategies showed no significant effect on outcomes.

CONCLUSIONS

In patients with critical illness or bleed, restricting blood transfusions by using a hemoglobin trigger of <7 g/dL significantly reduces cardiac events, rebleeding, bacterial infections, and total mortality. A less restrictive transfusion strategy was not effective.

Blood transfusion in hip arthroplasty: a laboratory hematic curve must be the single predictor of the need for transfusion?

Objective

to determine whether the laboratory hematic curve must be the single predictor of postoperative blood transfusion in total hip arthroplasty.

Methods

the laboratory blood samples of 78 consecutive patients undergoing total hip arthroplasty was analyzed during five distinct moments: one preoperative and four postoperative. There was a count of hemoglobin, hematocrit and platelets of the patients samples. Other catalogued variables ascertain possible risk factors related to transfusional practice. They characterized the anthropometric, behavioral and co morbidities data in this population. The study subjects were divided and categorized into two groups: those who received blood transfusion during or after surgery (Group 1, G1), and those who did not accomplish blood transfusion (Group 2, G2). Transfusion rules were lead by guidelines of American Academy of Anesthesiology and the British Society of Hematology.

Results

a total of 27 (34.6%) patients received blood transfusions. The curves of hemoglobin, hematocrit and platelet transfusions between G1 and G2 were similar (p > 0.05). None of the analyzed risk factors modified the rate of transfusion rate in their analysis with p value > 0.05, except the race. The sum of clinical co morbidities associated with patients in G1 was a median of 3 (95% CI 2.29–3.40), while in G2 the median was 2 (95% CI 1.90–2.61) with p = 0.09.

Conclusion

the curve in red blood cells has limited reliability when used as sole parameter. The existence of tolerant patients hematimetric curve variations assumes that their assessments of clinical, functional evaluation and co-morbidities are parameters that should influence the decision to transfusion red blood cells.