A prospective, randomized trial limiting perioperative red blood cell transfusions in vascular patients

Gastrointestinal Bleeding in Patients With Acute Ischemic Stroke: A Literature Review

Stroke is an infarction of the central nervous system (brain, spinal cord, or retina) that results from a disruption in cerebral blood flow either due to ischemia or hemorrhage. Complications of acute stroke are common and include pneumonia, urinary tract infection, myocardial infarction, deep vein thrombosis, and pulmonary embolism, among several others, all of which increase the risk of poor clinical outcomes. Gastrointestinal bleeding is a well-known complication that can occur during the acute phase of stroke. In this review, we have summarized the existing data regarding the incidence, pathophysiology, risk factors, morbidity, mortality, and management strategies for gastrointestinal bleeding in patients with acute ischemic stroke.

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.

How I treat anemia with red blood cell transfusion and iron

Severe anemia is commonly treated with red blood cell transfusion. Clinical trials have demonstrated that a restrictive transfusion strategy of 7 to 8 g/dL is as safe as a liberal transfusion strategy of 9 to 10 g/dL in many clinical settings. Evidence is lacking for subgroups of patients, including those with preexisting coronary artery disease, acute myocardial infarction, congestive heart failure, and myelodysplastic neoplasms. We present 3 clinical vignettes that highlight the clinical challenges in caring for patients with coronary artery disease with gastrointestinal bleeding, congestive heart failure, or myelodysplastic neoplasms. We emphasize that transfusion practice should be guided by patient symptoms and preferences in conjunction with the patient's hemoglobin concentration. Along with the transfusion decision, evaluation and management of the etiology of the anemia is essential. Iron-restricted erythropoiesis is a common cause of anemia severe enough to be considered for red blood cell transfusion but diagnosis and management of absolute iron deficiency anemia, the anemia of inflammation with functional iron deficiency, or their combination may be problematic. Intravenous iron therapy is generally the treatment of choice for absolute iron deficiency in patients with complex medical disorders, with or without coexisting functional iron deficiency.

Transfusion trigger after operations in high cardiac risk patients (TOP) trial protocol. Protocol for a multicenter randomized controlled transfusion strategy trial

BACKGROUND

There is substantial uncertainty regarding the effects of restrictive postoperative transfusion among patients who have underlying cardiovascular disease. The TOP Trial's objective is to compare adverse outcomes between liberal and restrictive transfusion strategies in patients undergoing vascular and general surgery operations, and with a high risk of postoperative cardiac events.

METHODS

A two-arm, single-blinded, randomized controlled superiority trial will be used across 15 Veterans Affairs hospitals with expected enrollment of 1520 participants. Postoperative transfusions in the liberal arm commence when Hb is <10 g/ dL and continue until Hb is greater than or equal to 10 g/dL. In the restrictive arm, transfusions begin when Hb is <7 g/dL and continue until Hb is greater than or equal to 7 g/dL. Study duration is estimated to be 5 years including a 3-month start-up period and 4 years of recruitment. Each randomized participant will be followed for 90 days after randomization with a mortality assessment at 1 year.

RESULTS

The primary outcome is a composite endpoint of all-cause mortality, myocardial infarction (MI), coronary revascularization, acute renal failure, or stroke occurring up to 90-days after randomization. Events rates will be compared between restrictive and liberal transfusion groups.

CONCLUSIONS

The TOP Trial is uniquely positioned to provide high quality evidence comparing transfusion strategies among patients with high cardiac risk. Results will clarify the effect of postoperative transfusion strategies on adverse outcomes and inform postoperative management algorithms.

TRIAL REGISTRATION

http://clinicaltrials.gov identifier: NCT03229941.

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.

A Systematic Review and Meta-analysis of Randomized Controlled Trials Comparing Intraoperative Red Blood Cell Transfusion Strategies

OBJECTIVE

The objective of this work was to carry out a meta-analysis of RCTs comparing intraoperative RBC transfusion strategies to determine their impact on postoperative morbidity, mortality, and blood product use.

SUMMARY OF BACKGROUND DATA

RBC transfusions are common in surgery and associated with widespread variability despite adjustment for casemix. Evidence-based recommendations guiding RBC transfusion in the operative setting are limited.

METHODS

The search strategy was adapted from a previous Cochrane Review. Electronic databases were searched from January 2016 to February 2021. Included studies from the previous Cochrane Review were considered for eligibility from before 2016. RCTs comparing intraoperative transfusion strategies were considered for inclusion. Co-primary outcomes were 30-day mortality and morbidity. Secondary outcomes included intraoperative and perioperative RBC transfusion. Meta-analysis was carried out using random-effects models.

RESULTS

Fourteen trials (8641 patients) were included. One cardiac surgery trial accounted for 56% of patients. There was no difference in 30-day mortality [relative risk (RR) 0.96, 95% confidence interval (CI) 0.71-1.29] and pooled postoperative morbidity among the studied outcomes when comparing restrictive and liberal protocols. Two trials reported worse composite outcomes with restrictive triggers. Intraoperative (RR 0.53, 95% CI 0.43-0.64) and perioperative (RR 0.70, 95% CI 0.62-0.79) blood transfusions were significantly lower in the restrictive group compared to the liberal group.

CONCLUSIONS

Intraoperative restrictive transfusion strategies decreased perioperative transfusions without added postoperative morbidity and mortality in 12/14 trials. Two trials reported worse outcomes. Given trial design and generalizability limitations, uncertainty remains regarding the safety of broad application of restrictive transfusion triggers in the operating room. Trials specifically designed to address intraoperative transfusions are urgently needed.

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.

Impact of Perioperative Blood Transfusion in Anemic Patients Undergoing Infra Inguinal Bypass

OBJECTIVE

Patients who present with lower extremity ischemia are frequently anemic and the optimal transfusion threshold for this cohort remains controversial. We sought to evaluate the impact of blood transfusion on postoperative major adverse cardiac events (MACE), including myocardial infarction, dysrhythmia, stroke, congestive heart failure, and 30-day mortality for these patients.

METHODS

All consecutive patients who underwent infra-inguinal bypass at our institution from 2011 to 2020 were included. Perioperative red blood cell transfusion was the primary exposure, and the primary outcome was MACE. Univariate and multivariable analyses were performed to assess the impact of patient and procedural variables, including red blood cell transfusion, stratified by hemoglobin (Hgb) nadir: <7, 7-8, and >8 g/dL.

RESULTS

Of the 287 patients reviewed for analysis, 146 (50.9%) had a perioperative transfusion (mean: 1.6 ± 3 units). Patients who received a transfusion had a mean nadir Hgb of 8.3 ± 1.0 g/dL, compared to 10.1 ± 1.7 g/dL without a transfusion. The overall incidence of MACE was 15.7% (45 of 287 patients). Univariate analysis demonstrated that MACE was associated with blood transfusion (P = 0.009), lower Hgb nadir (P = 0.02), and higher blood loss (P = 0.003). On multivariate analysis, transfusion was independently associated with MACE for patients with a Hgb nadir >8 g/dL (OR: 3.09; P = 0.006), but not for patients with Hgb nadir 7-8 g/dL (OR: 0.818; P = 0.77). Additionally, patients with MACE had significantly longer length of hospital stay than for patients without (13 vs. 7.7 days, P = 0.001).

CONCLUSIONS

For patients undergoing infra-inguinal bypass, receiving a red blood cell transfusion with a Hgb nadir >8 g/dL was associated with a 3-fold increase in MACE, with nearly twice the length of stay. For patients with a Hgb 7-8 g/dL, transfusion did not increase or reduce the incidence of MACE. These findings suggest no benefit of blood transfusion for patients with Hgb nadir >7 g/dL and harm for Hgb >8 g/dL, however causation cannot be proven due to the retrospective nature of the study and randomized studies are needed to confirm or refute these findings.

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.

Effect of low vs high haemoglobin transfusion trigger on cardiac output in patients undergoing elective vascular surgery: Post-hoc analysis of a randomized trial

BACKGROUND

During vascular surgery, restricted red-cell transfusion reduces frontal lobe oxygen (ScO₂ ) saturation as determined by near-infrared spectroscopy. We evaluated whether inadequate increase in cardiac output (CO) following haemodilution explains reduction in ScO₂ .

METHODS

This is a post-hoc analysis of data from the Transfusion in Vascular surgery (TV) Trial where patients were randomized on haemoglobin drop below 9.7 g/dL to red-cell transfusion at haemoglobin below 8.0 (low-trigger) vs 9.7 g/dL (high-trigger). Fluid administration was guided by optimizing stroke volume. We compared mean intraoperative levels of CO, haemoglobin, oxygen delivery, and CO at nadir ScO₂ with linear regression adjusted for age, operation type and baseline. Data for 46 patients randomized before end of surgery were included for analysis.

RESULTS

The low-trigger resulted in a 7.1% lower mean intraoperative haemoglobin level (mean difference, -0.74 g/dL; P < .001) and reduced volume of red-cell transfused (median [inter-quartile range], 0 [0-300] vs 450 mL [300-675]; P < .001) compared with the high-trigger group. Mean CO during surgery was numerically 7.3% higher in the low-trigger compared with the high-trigger group (mean difference, 0.36 L/min; 95% confidence interval (CI.95), -0.05 to 0.78; P = .092; n = 42). At the nadir ScO₂ -level, CO was 11.9% higher in the low-trigger group (mean difference, 0.58 L/min; CI.95, 0.10-1.07; P = .024). No difference in oxygen delivery was detected between trial groups (MD, 1.39 dL_O2 /min; CI.95, -6.16 to 8.93; P = .721).

CONCLUSION

Vascular surgical patients exposed to restrictive RBC transfusion elicit the expected increase in CO making it unlikely that their potentially limited cardiac capacity explains the associated ScO₂ decrease.

Restrictive Transfusion Strategy and Clinical Decision Support Practices for Reducing RBC Transfusion Overuse

OBJECTIVES

Assess support for the effectiveness of two separate practices, restrictive transfusion strategy and computerized physician order entry/clinical decision support (CPOE/CDS) tools, in decreasing RBC transfusions in adult surgical and nonsurgical patients.

METHODS

Following the Centers for Disease Control and Prevention Laboratory Medicine Best Practice (LMBP) Systematic Review (A-6) method, studies were assessed for quality and evidence of effectiveness in reducing the percentage of patients transfused and/or units of blood transfused.

RESULTS

Twenty-five studies on restrictive transfusion practice and seven studies on CPOE/CDS practice met LMBP inclusion criteria. The overall strength of the body of evidence of effectiveness for restrictive transfusion strategy and CPOE/CDS was rated as high.

CONCLUSIONS

Based on these procedures, adherence to an institutional restrictive transfusion strategy and use of CPOE/CDS tools for hemoglobin alerts or reminders of the institution's restrictive transfusion policies are effective in reducing RBC transfusion overuse.

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.

Low vs high hemoglobin trigger for transfusion in vascular surgery: a randomized clinical feasibility trial

Current guidelines advocate to limit red blood cell (RBC) transfusion during surgery, but the feasibility and safety of such a strategy remain unclear, as the majority of evidence is based on postoperatively stable patients. We assessed the effects of a protocol aiming to restrict RBC transfusion throughout hospitalization for vascular surgery. Fifty-eight patients scheduled for lower limb bypass or open abdominal aortic aneurysm repair were randomly assigned, on hemoglobin drop below 9.7 g/dL, to either a low-trigger (hemoglobin &lt; 8.0 g/dL) or a high-trigger (hemoglobin &lt; 9.7 g/dL) group for RBC transfusion. Near-infrared spectroscopy assessed intraoperative oxygen desaturation in brain and muscle. Explorative outcomes included nationwide registry data on death and major vascular complications. The primary outcome, mean hemoglobin within 15 days of surgery, was significantly lower in the low-trigger group, at 9.46 vs 10.33 g/dL in the high-trigger group (mean difference, −0.87 g/dL; P = .022), as were units of RBCs transfused (median [interquartile range (IQR)], 1 [0-2] vs 3 [2-6]; P = .0015). Although the duration and magnitude of cerebral oxygen desaturation increased in the low-trigger group (median [IQR], 421 [42-888] vs 127 [11-331] minutes × %; P = .0036), muscle oxygenation was unaffected. The low-trigger group associated to a higher rate of death or major vascular complications (19/29 vs 8/29; hazard ratio, 3.20; P = .006) and fewer days alive outside the hospital within 90 days (median [IQR], 76 [67-82] vs 82 [76-84] days; P = .049). In conclusion, a perioperative protocol restricting RBC transfusion successfully separated hemoglobin levels and RBC units transfused. Exploratory outcomes suggested potential harm with the low-trigger group and warrant further trials before such a strategy is universally adopted. This trial was registered at www.clinicaltrials.gov as #NCT02465125.

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.

Risks of restrictive red blood cell transfusion strategies in patients with cardiovascular disease (CVD): a meta-analysis

AIM

To evaluate the risks of restrictive red blood cell transfusion strategies (haemoglobin 7-8 g dL^-1 ) in patients with and without known cardiovascular disease (CVD).

BACKGROUND

Recent guidelines recommend restrictive strategies for CVD patients hospitalised for non-CVD indications, patients without known CVD and patients hospitalised for CVD corrective procedures.

METHODS/MATERIALS

Database searches were conducted through December 2017 for randomised clinical trials that enrolled patients with and without known CVD, hospitalised either for CVD-corrective procedures or non-cardiac indications, comparing effects of liberal with restrictive strategies on major adverse coronary events (MACE) and death.

RESULTS

In CVD patients not undergoing cardiac interventions, a liberal strategy decreased (P = 0·01) the relative risk (95% CI) (RR) of MACE [0·50 (0·29-0·86)] (I²  = 0%). Among patients without known CVD, the incidence of MACE was lower (1·7 vs 3·9%), and the effect of a liberal strategy on MACE [0·79, (0·39-1·58)] was smaller and non-significant but not different from CVD patients (P = 0·30). Combining all CVD and non-CVD patients, a liberal strategy decreased MACE [0·59, (0·39-0·91); P = 0·02]. Conversely, among studies reporting mortality, a liberal strategy decreased mortality in CVD patients (11·7% vs·13·3%) but increased mortality (19·2% vs 18·0%) in patients without known CVD [interaction P = 0·05; ratio of RR 0·73, (0·53-1·00)]. A liberal strategy also did not benefit patients undergoing cardiac surgery; data were insufficient for percutaneous cardiac procedures.

CONCLUSIONS

In patients hospitalised for non-cardiac indications, liberal transfusion strategies are associated with a decreased risk of MACE in both those with and without known CVD. However, this only provides a survival benefit to CVD patients not admitted for CVD-corrective procedures.

Impact of a restrictive vs liberal transfusion strategy on anastomotic leakage and infectious complications after restorative surgery for rectal cancer

AIM

The aim of this study was to investigate the impact of a restrictive vs liberal transfusion strategy on anastomotic leakage and infectious complications after rectal cancer surgery.

METHODS

Patients undergoing restorative proctectomy for rectal cancer between January 2008 and December 2013 were divided into four groups according to the perioperative lowest haemoglobin (Hgb) level and transfusion status: group 1 with Hgb level ≥ 10 g/dl; group 2 with Hgb level ≥ 7 and < 10 g/dl who did not receive transfusion; and group 3 with Hgb level ≥ 7 and < 10 g/dl and group 4 with Hgb level < 7 g/dl, both of which received a transfusion. Clinical characteristics, anastomotic leakage and infectious complications within 30 days of surgery were compared.

RESULTS

There were 398 patients (66% men) with a mean age of 59.3 ± 11.9 years. Groups 1, 2, 3 and 4 included 162 (40.7%), 163 (41.0%), 47 (11.8%) and 26 (6.5%) patients, respectively. Perioperative characteristics were significantly different among groups regarding neoadjuvant chemo/radiotherapy use, preoperative albumin and Hgb levels, operative approach and blood loss, tumour size and stage, surgical margin involvement and histological differentiation. The unadjusted rates of overall infectious complications were 17.2%, 27.6%, 36.2% and 50% in groups 1, 2, 3 and 4, respectively (P = 0.001). In the multivariate analysis, compared to group 2, group 3 was associated with an increased likelihood of organ/space surgical site infections (SSIs) (OR 3.63, 95% CI 1.29-10.22, P = 0.01) with no significant differences in terms of anastomotic leakage, overall SSIs or overall infectious complications.

CONCLUSION

Blood transfusion of haemodynamically stable patients with Hgb level ≥ 7 g/dl is associated with increased organ/space SSIs in rectal cancer surgery.

Variation in Transfusion Practices and the Association with Perioperative Adverse Events in Patients Undergoing Open Abdominal Aortic Aneurysm Repair and Lower Extremity Arterial Bypass in the Vascular Quality Initiative

BACKGROUND

Blood transfusions are associated with adverse events. We examined perioperative transfusion practices and associated complications following open vascular procedures nationwide in the Vascular Quality Initiative (VQI).

METHODS

Adults undergoing open abdominal aortic aneurysm repair (OAR) and lower extremity arterial bypass (Bypass) within VQI (2003-2016) were identified. All emergent cases, patients with preoperative hemoglobin <7 g/dL, preoperative hospitalization >1 day, or a return to operating room during the index hospitalization were excluded. Units of red blood cells transfused were the primary outcome. Secondary outcomes were postoperative myocardial infarction (MI) and death. Patient, center, and procedural factors were evaluated. Multivariable mixed effects negative binomial regression and multivariable logistic regression were performed.

RESULTS

We identified 24,131 procedures (OAR 3885, 16.1%; Bypass 20,246, 83.9%) among 22,532 patients (10.1% had >1 procedure). Overall, 37.5% of OAR and 19.5% of Bypass were transfused. Transfusion rates varied across estimated blood loss quartiles and across various preoperative hemoglobin levels. The overall rate of postoperative MI and death was 4.0% and 1.8% for OAR, and 2.2% and 0.7% for Bypass, respectively. In univariate and multivariable analysis, transfusions were associated with an increased risk of postoperative MI and death. A mixed effects negative binomial model demonstrated variation in transfusions across centers (P < 0.001). Female gender and preoperative anemia were significantly associated with transfusions.

CONCLUSIONS

Blood transfusions are variable across centers in VQI. Transfusions are associated with a higher postoperative MI and death after OAR and Bypass. Efforts to reduce transfusion may focus on center variability, gender, and preoperative anemia.

Anemia and blood transfusion in the critically ill patient with cardiovascular disease

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2017. Other selected articles can be found online at http://ccforum.com/series/annualupdate2017 . Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901 .

The Association of Peri-Procedural Blood Transfusion with Morbidity and Mortality in Patients Undergoing Percutaneous Lower Extremity Vascular Interventions: Insights from BMC2 VIC

Objective

To determine the predictors of periprocedural blood transfusion and the association of transfusion on outcomes in high risk patients undergoing endoluminal percutaneous vascular interventions (PVI) for peripheral arterial disease.

Methods/Results

Between 2010–2014 at 47 hospitals participating in a statewide quality registry, 4.2% (n = 985) of 23,273 patients received a periprocedural blood transfusion. Transfusion rates varied from 0 to 15% amongst the hospitals in the registry. Using multiple logistic regression, factors associated with increased transfusion included female gender (OR = 1.9; 95% CI: 1.6–2.1), low creatinine clearance (1.3; 1.1–1.6), pre-procedural anemia (4.7; 3.9–5.7), family history of CAD (1.2; 1.1–1.5), CHF (1.4; 1.2–1.6), COPD (1.2; 1.1–1.4), CVD or TIA (1.2; 1.1–1.4), renal failure CRD (1.5; 1.2–1.9), pre-procedural heparin use (1.8; 1.4–2.3), warfarin use (1.2; 1.0–1.5), critical limb ischemia (1.7; 1.5–2.1), aorta-iliac procedure (1.9; 1.5–2.5), below knee procedure (1.3; 1.1–1.5), urgent procedure (1.7; 1.3–2.2), and emergent procedure (8.3; 5.6–12.4). Using inverse weighted propensity matching to adjust for confounders, transfusion was a significant risk factor for death (15.4; 7.5–31), MI (67; 29–150), TIA/stroke (24; 8–73) and ARF (19; 6.2–57). A focused QI program was associated with a 28% decrease in administration of blood transfusion (p = 0.001) over 4 years.

Conclusion

In a large statewide PVI registry, post procedure transfusion was highly correlated with a specific set of clinical risk factors, and with in-hospital major morbidity and mortality. However, using a focused QI program, a significant reduction in transfusion is possible.

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.

Ideal hemoglobin transfusion target for resuscitation of massive-transfusion patients

BACKGROUND

Overtransfusion of packed red blood cells is known to increase the risk of death in stable patients. With the delineation of minimum transfusion ratios in hemorrhaging patients complete, attention must be turned to the other end of the massive transfusion spectrum-that of defining the maximum transfusion of packed red blood cells. We aimed to define the ideal hemoglobin range 24 hours after anatomic hemostasis associated with the lowest mortality.

METHODS

Massive-transfusion patients (≥10 units packed red blood cells within 24 hours) were reviewed from 2010-2013. The hemoglobin 24 ± 6 hours after anatomic hemostasis was used to stratify patients into undertransfusion (<8.0 g/dL), hemoglobin transfusion target (8.0-11.9 g/dL), and overtransfusion (>12.0 g/dL) groups; patients not surviving to 24 hours were excluded.

RESULTS

We identified 418 patients (351 [84%] in the hemoglobin transfusion target group, 38 [9%] in the undertransfusion group, and 29 [7%] in the overtransfusion group) with an overall mortality of 18%. Undertransfusion patients had the greatest risk of death (odds ratio 3.3; 95% confidence interval 1.6-6.7) followed by overtransfusion patients (odds ratio 2.5; 95% confidence interval 1.1-5.6). Though pretransfusion hemoglobin was similar (9.5 ± 2.2 g/dL vs 9.5 ± 2.3 g/dL), overtransfusion patients had greater hemoglobin values during massive transfusion (8.3 ± 3.0 g/dL vs 6.9 ± 1.4 g/dL), persisting until hospital dismissal/death (11.4 ± 2.3 g/dL vs 9.6 ± 1.1 g/dL). In total, 657.4 excess packed red blood cell units were transfused (1.9 ± 1.5 per patient).

CONCLUSION

Overtransfusion patients had increased mortality, comparable to undertransfusion patients, despite younger age and fewer comorbidities. Shorter massive transfusion durations foster a scenario in which patients are at greater risk of overtransfusion.

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.

Spectrum of Sickle Cell Diseases in Patients Diagnosed at a Tertiary Care Centre in Karnataka with Special Emphasis on their Clinicohaematological Profile

INTRODUCTION

Sickle cell disease is a monogenic disorder with considerable clinical diversity and Sickle haemoglobin is responsible for wide spectrum of disorders which vary with respect to severity of anaemia, frequency of crises and duration of survival. As they are confused with many other clinically aggressive disorders, precision in diagnosis is essential both to proper clinical management and subsequent genetic counselling. Hence, this study was taken up in order to diagnose these conditions and administer suitable counselling measures to minimise the incidence of sickle cell disease in the future.

AIM

The aim of this study was to identify the spectrum of all Sickle cell diseases diagnosed at a tertiary care centre in Bangalore, Karnataka, India who presented over a period of five years from 2009 to 2013 and also to screen the parents and siblings of the patients for their carrier status.

MATERIALS AND METHODS

We reviewed 26 cases of Sickle Cell Disease (SCD) and also 38 parents & 10 siblings of these children for their carrier status. Haemoglobin electrophoreses was performed by using alkaline gel method, followed by High Performance Liquid Chromatography when needed.

RESULTS

A total of 26 children diagnosed with SCD were enrolled in the study. Most common entity was Sickle Cell Anaemia (SCA), followed by sickle thalassaemia and Sickle Cell Trait (SCT). Commonest clinical presentation was fever and pallor. Amongst the parents and siblings, sickle cell trait was the most common entity followed by thalassaemia trait. One interesting case of HbSE disease was encountered, which is a rare entity in India.

CONCLUSION

This study brings out the total spectrum of SCDs in a tertiary care centre in Karnataka, with more emphasis on screening of the parents and siblings for their carrier status.

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.

Impact of Transfusion Threshold on Infectious Complications After Ileal Pouch-Anal Anastomosis

BACKGROUND

This study was conducted to investigate the impact of different hemoglobin level-based transfusion practices on infectious complications after surgery for ulcerative colitis.

METHODS

Patients who underwent ileal pouch-anal anastomosis for ulcerative colitis between January 2008 and December 2013 were identified and divided into four groups: group 1 with hemoglobin ≥ 10 and group 2 with hemoglobin ≥ 7 and <10 g/dL who did not receive transfusion and group 3 with hemoglobin ≥ 7 and <10 and group 4 with hemoglobin < 7 g/dL who received transfusion. Clinical characteristics and septic complications within postoperative 30 days were compared.

RESULTS

There were 237, 341, 40, and 20 patients in groups 1, 2, 3, and 4, respectively. All the groups were comparable regarding perioperative characteristics except for age, gender, preoperative albumin and hemoglobin levels, and operative blood loss. The rates of overall septic complications were 18.6, 26.7, 47.5, and 40 % in the groups 1, 2, 3 and 4, respectively. In multivariate analysis, compared to group 2, group 3 was associated with an increased likelihood of developing organ/space (odds ratio (OR) = 4.34, p = 0.004) and overall surgical site infections (SSIs) (OR = 2.81, p = 0.01).

CONCLUSION

Blood transfusion decided based on a perioperative hemoglobin (Hgb) level above 7 mg/dL is associated with higher overall and organ/space SSIs.

Blood Conservation in Cardiac Surgery

Blood transfusion is the most common procedure in cardiac surgery. Increasing evidence exists that excess transfusions are harmful to patients. Transfusion reactions and complications, including infection, immune modulation, and lung injury, are known complications but underreported; hence, their significance is often disregarded. Furthermore, a number of randomized trials have shown that a restrictive transfusion strategy is equal to if not better than a liberal transfusion strategy. Despite the evidence for the use of restrictive transfusion triggers, its dissemination in the cardiac surgical community has met with resistance. In this review, we outline the risks of transfusion, compare restrictive and liberal transfusion strategies in cardiac surgery, and finally outline perioperative interventions to minimize transfusion in the cardiac surgical patient.

Frequency distribution of sickle cell anemia, sickle cell trait and sickle/beta-thalassemia among anemic patients in Saudi Arabia

Background:

Notwithstanding, the growing incidence of sickle cell hemoglobinopathies (SCH) such as sickle cell anemia (SCA) or sickle cell disease, sickle/beta-thalassemia; the exact prevalence remains obscure in Saudi Arabia. Hence, this study is an attempt to determine the frequency of SCA and sickle cell trait (SCT) among all anemic patients with SCH treated at the King Abdul-Aziz Medical City (KAMC), Riyadh, Saudi Arabia. Furthermore, the hemoglobin (Hb) S and other Hb patterns (Hb AS and Hb F) were also estimated in SCA and SCT patients.

Materials and Methods:

Results of Hb capillary electrophoresis performed on all patients with SCH from January 2011 to December 2013 were evaluated retrospectively.

Results:

Of a total of 3332 patient data analyzed, 307 were anemic patients (58% males and 42% females) with SCH. The sickling test showed all the patients to be positive. Hb electrophoresis revealed the incidence of 96.7%, 3.3%, and 0% of the patients suffered from SCA, SCT and sickle/beta-thalassemia, respectively. Patients with SCA had a higher level of Hb F and showed no crisis when compared with other SCA patients who had lower or no Hb F levels.

Conclusion:

SCA is relatively frequent among males (56.4%) than females out of all patients with SCH. The SCA incidence was more common (48.5%) among children, frequency of SCT among adult age group was 1.6%, while sickle/beta-thalassemia was 0%.

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.

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.

Transfusion triggers for guiding RBC transfusion for cardiovascular surgery: a systematic review and meta-analysis*

OBJECTIVE

Restrictive red cell transfusion is recommended to minimize risk associated with exposure to allogeneic blood. However, perioperative anemia is an independent risk factor for adverse outcomes after cardiovascular surgery. The purpose of this systematic review and meta-analysis is to determine whether perioperative restrictive transfusion thresholds are associated with inferior clinical outcomes in randomized trials of cardiovascular surgery patients.

DATA SOURCES

The Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE from inception to October 2013; reference lists of published guidelines, reviews, and associated articles, as well as conference proceedings. No language restrictions were applied.

STUDY SELECTION

We included controlled trials in which adult patients undergoing cardiac or vascular surgery were randomized to different transfusion thresholds, described as a hemoglobin or hematocrit level below which RBCs were transfused.

DATA EXTRACTION

Two authors independently extracted data from included trials. We pooled risk ratios of dichotomous outcomes and mean differences of continuous outcomes across trials using random-effects models.

DATA SYNTHESIS

Seven studies (enrolling 1,262 participants) met inclusion criteria with restrictive and liberal transfusion thresholds most commonly differing by a hemoglobin of 1 g/dL or hematocrit of 6-7%, resulting in decreased transfusions by 0.71 units of RBCs (95% CI, 0.31-1.09, p = 0.0002) without an associated change in adverse events: mortality (risk ratio, 1.12; 95% CI, 0.65-1.95; p = 0.60), myocardial infarction (risk ratio, 0.94; 95% CI, 0.30-2.99; p = 0.92), stroke (risk ratio, 1.15; 95% CI, 0.57-2.32; p = 0.70), acute renal failure (risk ratio, 0.98; 95% CI, 0.64-1.49; p = 0.91), infections (risk ratio, 1.23; 95% CI, 0.85-1.78; p = 0.27), or length of stay. There was no between-trial heterogeneity for any pooled analysis. Including four pediatric trials (456 participants) and 10 trials utilizing only intraoperative acute normovolemic hemodilution (872 participants) did not substantially change the results except that unlike the transfusion threshold trials, the hemodilution trials did not reduce the proportion of patients transfused (interaction p = 0.01).

CONCLUSIONS

Further randomized controlled trials are necessary to determine the optimal transfusion strategy for patients undergoing cardiovascular surgery.

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 utilization after primary total joint arthroplasty in a large hospital network

BACKGROUND

Since a study in orthopedic hip fracture patients demonstrated that a liberal hemoglobin (Hb) threshold does not improve patient morbidity and mortality relative to a restrictive Hb threshold, the standard of care in total joint arthroplasty (TJA) should be examined to understand the variability of red blood cell (RBC) transfusion following TJA.

QUESTIONS/PURPOSES

The study aimed to answer the following questions: (1) What is the blood utilization rate after primary TJA for individual surgeons within a large hospital network? (2) What is the comparison of hospital charges, length of stay (LOS), and discharge locations among TJA patients who were and were not transfused?

METHODS

A retrospective study was conducted on 3,750 primary total knee arthroplasties (TKAs) and 2,070 primary total hip arthroplasties (THAs), and data was retrospectively collected over a 15-month period on the number of RBCs transfused per patient, along with demographic and cost details. The number of patients who received at least 1 RBC unit and the number of RBCs transfused per patient was calculated and stratified by surgeon.

RESULTS

In the postoperative period, 19.3% TKA patients and 38.5% THA patients received a RBC transfusion. Transfusion rates following TJA varied widely between surgeons (TKA 4.8-63.8%, THA 4.3-86.8%). Transfused TKA patients received an average of 1.65 ± 0.03 RBCs, and THA patients received an average of 1.97 ± 0.14 RBCs. LOS and hospital charges for blood transfusion patients were higher than nontransfused patients.

CONCLUSION

Blood utilization after primary TJA varies greatly among surgeons, suggesting that resources may be misallocated. These findings highlight the need to standardize RBC transfusion practice following TJA.

Impact of postoperative nadir hemoglobin and blood transfusion on outcomes after operations for atherosclerotic vascular disease

OBJECTIVE

Controversy surrounds the topic of transfusion policy after noncardiac operations. This study assessed the combined impact of postoperative nadir hemoglobin (nHb) levels and blood transfusion on adverse events after open surgical intervention in patients who undergo operative intervention for atherosclerotic vascular disease.

METHODS

Consecutive patients who underwent peripheral arterial disease (PAD)-related operations were balanced on baseline characteristics by inverse weighting on propensity score calculated as their probability to have nHb greater than 10 gm/dL on the basis of operation type, demographics, and comorbidities, including the revised cardiac risk index. A multivariate generalized estimating equation analysis was performed to investigate associations between nHb, transfusion, and a composite outcome of perioperative death and myocardial infarction. Logistic and Cox proportional hazards regressions were used to assess the impact of nHb and transfusion on respiratory and wound complications; and a composite end point (CE) of death, myocardial infarction during a 2-year follow-up. Level of statistical significance was set at alpha of 0.0125 to adjust for the increased probability of type I error attributable to multiple comparisons.

RESULTS

The analysis cohort included 880 patients (1074 operations). After adjusting for nHb level, the number of units transfused was not associated with the perioperative occurrence of the CE (odds ratio [OR], 1.13; P = .025). Adjusted for the number of units transfused, nHb had no impact on the perioperative CE (OR, 0.62; P = .22). An interaction term between transfusion and nHb level remained nonsignificant (P = .312), indicating that the impact of blood transfusion was the same regardless of the nHb level. Perioperative respiratory complications were more likely in patients receiving transfusions (OR, 1.22; P = .009), and perioperative wound infections were less common in patients with nHb >10 gm/dL (OR, 0.65; P = .01). During an average follow-up of 24 months, transfused patients were more likely to develop the CE (hazard ratio [HR], 1.15, P = .009), whereas nHb level did not impact the long-term adverse event rate (HR, 0.78; P = .373). The above associations persisted even after adjusting the Cox regression model for the occurrence of perioperative cardiac events.

CONCLUSIONS

Although nHb less than 10 gm/dL is not associated with death or ACS after PAD-related operations, maintaining nHb greater than 10 gm/dL appears to decrease the risk of wound infection. Blood transfusion is associated with increased risk of perioperative respiratory complications. Until a randomized trial settles this issue definitively, a restrictive transfusion strategy is justified in patients undergoing operations for atherosclerotic vascular disease.

[Erythrocyte transfusions: an evidence-based approach]

Few randomized controlled studies, the only trial design where causality can be established between an intervention and the benefits or harms thereof, have been published on the benefits and risks of a restrictive vs a liberal transfusion strategy. We review the 19 controlled studies on erythrocyte transfusion thresholds published since the eighties. These studies suggest that, overall, morbidity (including cardiac morbidity) and mortality, along with hemodynamic, respiratory and oxygen transport variables, are similar when a restrictive transfusion strategy (transfusion threshold between 7 and 8 g/dL) or a liberal strategy (transfusion threshold of 10 g/dL) are used. In fact, a restrictive strategy can even be associated with a number of benefits. The relevance of a higher transfusion threshold in view of avoiding morbidity in patients presenting a cardiovascular risk is unlikely, at least uncertain. Finally, anaemia has little or no impact on functional recovery and on quality of life, whether in the immediate or late postoperative period. It is clear that a restrictive strategy is associated with a reduced exposure to red cell transfusions, allowing a reduction in transfusion-related adverse events. Thus, all red cell transfusions must be tailored to the patient's needs, at the time the need prevails. In conclusion, most recommendations on transfusion practice are limited by the lack of evidence-based data and reveal our ignorance on the topic. High quality clinical trials in different patient populations must become available in order to determine optimal transfusion practices. Since then, a restrictive strategy aiming for a moderately anaemic threshold (7-8 g/dL) is appropriate under most circumstances.