Transfusion requirements after head trauma: a randomized feasibility controlled trial

Transfusion Thresholds and Neurological Functional Outcome After Acute Brain Injury: An Updated Systematic Review and Meta-Analysis of Randomized Clinical Trials

Background/Objectives: The benefits of liberal transfusion strategies for neurological outcomes in critically ill patients with acute brain injuries (ABIs) remain uncertain due to conflicting evidence and potential risks. This study aimed to evaluate the efficacy and safety of a liberal transfusion strategy in adults with ABI. Methods: A systematic review of PubMed, Scopus, and the Cochrane Library was conducted from inception until 18 December 2024. Randomized clinical trials (RCTs) comparing liberal and restrictive transfusion strategies in adult patients admitted to intensive care units with ABI were included. The primary outcome was unfavorable neurological function at the last follow-up, defined as Glasgow Outcome Scale (GOS) score <4, Extended GOS score <5, or modified Rankin Scale score >3. Results: Among 5859 screened records, five RCTs (2385 patients) met the inclusion criteria. Liberal transfusion significantly reduced unfavorable neurological outcomes (RR, 0.88; 95% CI, 0.82-0.95; p = 0.0009) without affecting mortality (RR, 0.97; 95% CI, 0.84-1.11; p = 0.66). A meta-analysis of two studies (n = 1465 patients) showed improved functional independence with liberal strategies (MD, 6.70; 95% CI, 2.07-11.33; p = 0.005) but no difference in quality of life (p = 0.30). Sepsis or septic shock occurred less frequently in the liberal group (RR, 0.68; 95% CI, 0.50-0.92; p = 0.01). Subgroup analysis indicated that liberal strategies improved neurological outcome in traumatic brain injury (TBI) patients (RR, 0.89; 95% CI, 0.82-0.97; p = 0.01) but did not yield significant differences in spontaneous subarachnoid hemorrhage (p = 0.09). Conclusions: Liberal transfusion strategies safely improve neurological outcomes in adults with ABI, specifically in the subgroup of TBI, whereas further studies are needed in patients with SAH.

Liberal transfusion strategies reduce sepsis risk and improve neurological recovery in acute brain injury: an updated systematic review and meta-analysis

PURPOSE

To advocate for a Liberal Transfusion Strategy (LTS) in neurocritical care patients with Acute Brain Injury (ABI) and provide updated evidence for optimizing transfusion thresholds in clinical guidelines.

BACKGROUND

Anemia frequently complicates ABI management, often necessitating red blood cell transfusions. However, the optimal hemoglobin (Hb) threshold for transfusion remains controversial. While earlier meta-analyses indicated no significant differences between LTS and restrictive transfusion strategies (RTS), emerging randomized controlled trials (RCTs) emphasize the need for reappraisal within neurocritical care.

METHODS

This meta-analysis included five RCTs involving 2399 patients (1,191 LTS; 1208 RTS) with ABI (subarachnoid hemorrhage, traumatic brain injury, or intracerebral hemorrhage). LTS was defined as transfusion at Hb ≤ 10-9 g/dL, and RTS as transfusion at Hb ≤ 7-8 g/dL. Outcomes assessed included sepsis or septic shock, ICU mortality, unfavorable functional outcomes at six months, venous thromboembolism (VTE), acute respiratory distress syndrome (ARDS), and in-hospital mortality.

RESULTS

RTS significantly increased the risk of sepsis or septic shock (relative risk [RR]: 1.42; 95% confidence interval [CI] 1.08-1.86; p = 0.01) and unfavorable functional outcomes at six months (RR 1.13; 95% CI 1.06-1.21; p = 0.0003). No significant differences were observed in ICU mortality (RR 1.00; 95% CI 0.84-1.20; p = 0.96), VTE (RR: 0.88; 95% CI 0.56-1.38; p = 0.58), ARDS (RR 1.05; 95% CI 0.69-1.61; p = 0.81), or in-hospital mortality (RR 0.98; 95% CI 0.76-1.26; p = 0.89). Heterogeneity was minimal (I2 < 25%).

CONCLUSION

LTS demonstrates the potential to enhance safety and functional recovery in ABI patients by mitigating sepsis risk and promoting favorable neurologic outcomes. Further high-powered RCTs are warranted to validate these findings and refine transfusion protocols.

Transfusion Thresholds in Patients With Neurological Injury: Balancing Oxygen Delivery and Risk

Transfusion strategies in neurocritical care require a delicate and nuanced balance between optimizing oxygen delivery to the injured brain and minimizing transfusion-associated risks. Although restrictive transfusion protocols are widely adopted in critical care, their applicability to patients with neurological injury remains the subject of debate. Anemia may exacerbate cerebral hypoxia, potentially worsening neurological outcomes, yet transfusion carries risks such as thrombosis, immune modulation, and increased intracranial pressure. Studies comparing liberal and restrictive transfusion strategies in neurocritical care have yielded mixed results, with most settling on the noninferiority of a restrictive approach while still considering a higher threshold for particular subgroups. This focused review will examine the current evidence on transfusion strategies in neurocritically ill patients and highlight key areas for future research.

Low Hemoglobin Causes Hematoma Expansion and Poor Intracerebral Hemorrhage Outcomes

BACKGROUND

Although lower hemoglobin levels associate with worse intracerebral hemorrhage (ICH) outcomes, causal drivers for this relationship remain unclear. We investigated the hypothesis that lower hemoglobin relates to increased hematoma expansion risk and poor outcomes using human observational data and assessed causal relationships using a translational murine model of anemia and ICH.

METHODS

A multicenter, prospective observational cohort study of 2997 patients with ICH enrolled between 2010 and 2016 was assessed. Patients with baseline hemoglobin measurements and serial computed tomography neuroimaging were included for analyses. Patients with systemic evidence of coagulopathy were excluded. Separate regression models assessed relationships of baseline hemoglobin with hematoma expansion (≥33% and/or ≥6 mL growth) and poor long-term neurological outcomes (modified Rankin Scale score of 4-6) after adjusting for relevant covariates. Using a murine collagenase ICH model with serial neuroimaging in anemic versus nonanemic C57/BL6 mice, intergroup differences in ICH lesion volume, lesion volume changes, and early mortality were assessed.

RESULTS

Among 1190 ICH patients analyzed, the mean age was 61 years old, and 62% of the cohort were males. Lower baseline hemoglobin levels are associated with increased odds of hematoma expansion (adjusted odds ratio per -1 g/dL hemoglobin decrement, 1.10 [95% CI, 1.02-1.19]) and poor 3-month clinical outcomes (adjusted odds ratio per -1 g/dL hemoglobin decrement, 1.11 [95% CI, 1.03-1.21]). Similar relationships were seen with poor 6- and 12-month outcomes. In our animal model, anemic mice had significantly greater ICH lesion expansion, 24-hour lesion volumes, and greater mortality, as compared with nonanemic mice.

CONCLUSIONS

These results, in a human cohort and a mouse model, provide novel evidence suggesting that anemia has causal roles in hematoma expansion and poor ICH outcomes. Additional studies are required to clarify whether correcting anemia can improve these outcomes.

Red blood cell transfusion strategy in traumatic brain injury patients: a systematic review and meta-analysis

BACKGROUND

The optimal red blood cell transfusion (RBCT) strategy for traumatic brain injury (TBI) patients remains a topic of debate. This systematic review and meta-analysis aimed to compare the outcomes of a liberal transfusion strategy versus a restrictive strategy in critically ill patients with TBI.

METHODS

PubMed, Web of Science, Embase, and Cochrane Library were searched from inception to November 17, 2024. We included randomized controlled trials (RCTs) of critically ill adult patients with TBI, reporting data on RBCT strategies. The outcomes included intensive care unit (ICU) mortality, long-term mortality, unfavorable functional outcomes, and the incidence of adverse events, such as transfused acute respiratory distress syndrome (TARDS) and venous thromboembolism. We also performed subgroup analyses comparing the association between disease severity and long-term mortality. This review was submitted to PROSPERO (Registration number: CRD42024558797).

RESULTS

In the results, our analysis revealed that compared to a restrictive transfusion strategy, a liberal strategy did not significantly reduce the risk of ICU mortality (RR: 0.74; 95% CI 0.28-1.91; P = 0.53) and long-term mortality (RR: 1.02; 95% CI 0.83-1.25; P = 0.87), but it was able to reduce the risk of unfavorable functional outcomes (RR: 0.90; 95% CI 0.82-0.98; P = 0.01), although there may be a false positive error. In addition, the liberal transfusion strategy was associated with a higher incidence of Transfused Acute Respiratory Distress Syndrome (TARDS) (RR: 1.78; 95% CI 1.06-2.98; P = 0.03).

CONCLUSIONS

In critically ill patients with TBI, a liberal RBCT strategy appears to improve functional outcomes but carries the risk of false positive errors. In addition, this strategy does not seem to improve survival and may increase the risk of TARDS. Despite this, there remains insufficient evidence to recommend either strategy in this population.

Management of severe traumatic brain injury in pediatric patients: an evidence-based approach

BACKGROUND

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. The decision-making process in the management of severe TBI must be based on the best available evidence to minimize the occurrence of secondary brain injuries. However, healthcare approaches to managing TBI patients exhibit considerable variation.

METHODS

Over an 18-month period, a multidisciplinary panel consisting of medical doctors, physiotherapists, nutritional therapists, and nurses performed a comprehensive review on various subtopics concerning TBI. The panel identified primary questions to be addressed using the Population, Intervention, Control, and Outcome (PICO) format and applied the Evidence to Decision (EtD) framework criteria for evaluating interventions. Subsequently, the panel formulated recommendations for the management of severe TBI in children.

RESULTS

Fourteen evidence-based recommendations have been devised for the management of severe TBI in children, covering nine topics, including imaging studies, neuromonitoring, prophylactic anticonvulsant use, hyperosmolar therapy, sedation and analgesia, mechanical ventilation strategies, nutritional therapy, blood transfusion, and decompressive craniectomy. For each topic, the panel provided clinical recommendations and identified research priorities.

CONCLUSIONS

This review offers evidence-based strategies aimed to guide practitioners in the care of children who suffer from severe TBI.

Liberal vs. restrictive transfusion strategies for acute brain injury: a systematic review and frequentist-Bayesian meta-analysis

PURPOSE

To determine whether a liberal transfusion strategy (≥ 9 g/dL) improves neurological outcomes in adults with acute brain injury (ABI).

METHOD

We systematically searched MEDLINE, EMBASE, the Cochrane Library, and trial registries for randomized controlled trials comparing liberal (≥ 9 g/dL) vs. restrictive (≥ 7 g/dL) transfusion in adults with ABI (traumatic brain injury, subarachnoid hemorrhage, intracranial hemorrhage) and Glasgow Coma Scale ≤ 13. Frequentist, Bayesian, and trial sequential analyses were used. The primary outcome was favorable neurological status at 180 days.

RESULTS

Four randomized controlled trials (N = 1853; 922 liberal, 931 restrictive) were included. The pooled frequentist risk ratio (RR) for favorable neurological outcome was 0.84 (95% CI 0.65-1.09; I2 = 58%). In a pre-specified sensitivity analysis including only low-risk-of-bias trials, the results suggested a potential benefit in favor of the liberal strategy (RR 0.74 [95% CI 0.63-0.87]) with no heterogeneity (I2 = 0%). Subgroup analyses for patients with traumatic brain injury or stratified by initial Glasgow coma scale were consistent with the main findings. Bayesian analyses showed that the estimated treatment effect depended on the assumptions and priors used, with an unfavorable prior derived from one trial with distinct protocol appearing less likely than neutral or favorable priors. Trial sequential analysis indicated that current evidence is insufficient to confirm a definitive effect. Secondary outcomes did not differ significantly between groups.

CONCLUSIONS

This review did not provide definitive evidence of a neurological benefit from liberal transfusion strategies in acute brain injury. Both frequentist and Bayesian analyses highlight the influence of a single trial on the overall effect estimate and heterogeneity. However, sensitivity analyses excluding this trial and focusing on studies with low risk of bias suggested that liberal transfusion strategies could improve neurological outcomes. Future research should focus on identifying patient subgroups most likely to benefit, guiding a more individualized approach.

Transfusion Practices in Traumatic Brain Injury: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Balancing oxygen requirements, neurologic outcomes, and systemic complications from transfusions in traumatic brain injury (TBI) patients is challenging. This review compares liberal and restrictive transfusion strategies in TBI patients.

DATA SOURCES

Electronic databases were searched from inception to October 2024.

STUDY SELECTION

We included randomized controlled trials comparing liberal and restrictive transfusion strategies in TBI patients.

DATA EXTRACTION

Data were extracted by two reviewers using predefined forms.

DATA SYNTHESIS

We included five studies with 1,533 patients: 769 (50.2%) in the liberal transfusion group and 764 (49.8%) in the restrictive group. There were no significant differences between groups favorable Glasgow Outcome Scale (risk ratio [RR], 1.16; 95% CI, 1.00-1.34), although a leave-one-out analysis demonstrated significance in this endpoint (RR, 1.24; 95% CI, 1.06-1.45). No significant difference was found regarding hospital mortality (RR, 0.98; 95% CI, 0.76-1.27), mortality at follow-up (RR, 1.03; 95% CI, 0.82-1.28), mortality in the ICU (RR, 1.00; 95% CI, 0.73-1.37), infection rates (RR, 1.08; 95% CI, 0.95-1.23), thromboembolic events (RR, 1.79; 95% CI, 0.74-4.31), hospital length of stay (LOS) (mean difference [MD], -1.45; 95% CI, -4.85 to 1.96), or ICU LOS (MD, -0.47; 95% CI, -3.84 to 2.91). The liberal transfusion strategy group had a significantly higher prevalence of acute respiratory distress syndrome (RR, 1.78; 95% CI, 1.06-2.98) and received more blood units per patient (MD, 2.62; 95% CI, 1.90-3.33).

CONCLUSIONS

Our findings suggest that a liberal transfusion strategy results in better neurologic outcomes than a restrictive approach. Future research should examine the complication profile and the effects of using a 9 g/dL threshold. We advocate for revising current guidelines to establish 9 g/dL as the standard threshold for transfusions in TBI patients.

An Overview of Adult Acute Traumatic Neurologic Injury for the Anesthesiologist: What is Known, What is New, and Emerging Concepts

Purpose of Review

We examine what is known, what is new, and what is emerging in acute neurotrauma relevant to the anesthesiologist.

Recent Findings

Timely and goal-directed care is critical for all patients requiring urgent/emergent anesthesia care. Anesthesia care for acute neurological injury should incorporate understanding the evolution of traumatic brain injury and spinal cord injury that translates to preoperative preparation, hemodynamic resuscitation, prevention of second insults, and safe transport between care settings. Anesthesia care should support optimizing patient outcomes.

Summary

Best practices involve extrapolating data from the intensive care unit setting since there is a lack of research addressing anesthesia care for acute neurological injury. There are opportunities to generate data to support evidence-based anesthetic care.

Real-world efficacy of transfusion with liberal or restrictive strategy in traumatic brain injury

OBJECTIVE

The short-term efficacy of red blood cell (RBC) transfusion among general traumatic brain injury (TBI) patients is unclear.

METHODS

We used the MIMIC database to compare the efficacy of liberal (10 g/dL) versus conservative (7 g/dL) transfusion strategy in TBI patients. The outcomes were neurological progression (decrease of Glasgow coma scale (GCS) of at least 2 points) and death within 28 days of ICU admission. Each eligible individual was cloned and assigned each of the replicates to one of the treatment arm. The imbalance induced by informative censoring was adjusted by inverse probability weighting. The standardized, weighted pooled logistic regression with 500 bootstrap resampling was used to estimate the cumulative risk difference and 95% confidence interval (CI).

RESULTS

Of the 1141 eligible individuals, 29.0% received RBC transfusion. Compared with the restrictive group, the liberal strategy reduced early death (3 days: 5%, 95% CI: 2%-7%; 7 days: 6%, 95% CI: 3%-11%); however, no significant difference of mortality risk at 28-day or neurological progression risk at any time points was observed. The risk of coagulopathy at 3 days was increased by 7% (95% CI: 1%-19%) in the liberal group. The subgroup analysis indicated a beneficial effect of liberal transfusion on mortality in hemodynamically unstable patients.

INTERPRETATION

Compared with the restrictive strategy, the liberal strategy does not improve the short-term neurological prognosis and death among patients with TBI in a real-world situation. The liberal strategy may be beneficial to survival at very early stage or in hemodynamically unstable subgroup.

Unravelling Secondary Brain Injury: Insights from a Human-Sized Porcine Model of Acute Subdural Haematoma

Traumatic brain injury (TBI) remains one of the leading causes of death. Because of the individual nature of the trauma (brain, circumstances and forces), humans experience individual TBIs. This makes it difficult to generalise therapies. Clinical management issues such as whether intracranial pressure (ICP), cerebral perfusion pressure (CPP) or decompressive craniectomy improve patient outcome remain partly unanswered. Experimental drug approaches for the treatment of secondary brain injury (SBI) have not found clinical application. The complex, cellular and molecular pathways of SBI remain incompletely understood, and there are insufficient experimental (animal) models that reflect the pathophysiology of human TBI to develop translational therapeutic approaches. Therefore, we investigated different injury patterns after acute subdural hematoma (ASDH) as TBI in a post-hoc approach to assess the impact on SBI in a long-term, human-sized porcine TBI animal model. Post-mortem brain tissue analysis, after ASDH, bilateral ICP, CPP, cerebral oxygenation and temperature monitoring, and biomarker analysis were performed. Extracerebral, intraparenchymal-extraventricular and intraventricular blood, combined with brainstem and basal ganglia injury, influenced the experiment and its outcome. Basal ganglia injury affects the duration of the experiment. Recognition of these different injury patterns is important for translational interpretation of results in this animal model of SBI after TBI.

Efficacy of restrictive versus liberal transfusion strategies in patients with traumatic brain injury: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

The effects of restrictive versus liberal transfusion strategies in critically ill patients with traumatic brain injury (TBI) and anemia, particularly in adult patients with moderate to severe TBI, remain inconclusive. Therefore, this systematic review and meta-analysis aim to evaluate the comparative impact of restrictive and liberal red blood cell transfusion strategies among critically ill adult patients with moderate to severe TBI.

METHODS

We conducted a search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from their inception through October 20, 2024, to identify randomized controlled trials that compared restrictive (transfusions at a hemoglobin level of ≤ 7 g/dL) and liberal (transfusions at a hemoglobin level of ≤ 9-10 g/dL) transfusion strategies in adult patients with TBI. The primary outcome was mortality, with secondary outcomes including an unfavorable neurological outcome at six months, as determined by the Glasgow Outcome Scale (GOS < 4; or Glasgow Outcome Scale-Extended [GOSE] < 6), and the number of units of packed red blood cells (pRBCs) transfused.

RESULTS

Five randomized controlled trials involving 1,528 patients were included in the analysis. The results showed that restrictive transfusion, compared to liberal transfusion, had no impact on mortality (RR 1.00, 95% CI 0.80 to 1.24, I2 = 0%) or unfavorable neurological outcome at 6 months (RR 1.06, 95% CI 0.94 to 1.20, I2 = 47%). Restrictive transfusion was associated with a reduction in the number of units of pRBCs transfused (MD -2.62, 95% CI -3.33 to -1.90, I2 = 63%).

CONCLUSION

In patients with TBI, a restrictive transfusion strategy did not reduce the risk of mortality or unfavorable neurological outcome compared with a liberal transfusion strategy.

Restrictive vs Liberal Transfusion Strategy in Patients With Acute Brain Injury: The TRAIN Randomized Clinical Trial

Importance

Blood transfusions are commonly administered to patients with acute brain injury. The optimal hemoglobin transfusion threshold is uncertain in this patient population.

Objective

To assess the impact on neurological outcome of 2 different hemoglobin thresholds to guide red blood cell transfusions in patients with acute brain injury.

Design, Setting, and Participants

Multicenter, phase 3, parallel-group, investigator-initiated, pragmatic, open-label randomized clinical trial conducted in 72 intensive care units across 22 countries. Eligible patients had traumatic brain injury, aneurysmal subarachnoid hemorrhage, or intracerebral hemorrhage; hemoglobin values below 9 g/dL within the first 10 days after injury; and an expected intensive care unit stay of at least 72 hours. Enrollment occurred between September 1, 2017, and December 31, 2022. The last day of follow-up was June 30, 2023.

Interventions

Eight hundred fifty patients were randomly assigned to undergo a liberal (transfusion triggered by hemoglobin <9 g/dL; n = 408) or a restrictive (transfusion triggered by hemoglobin <7 g/dL; n = 442) transfusion strategy over a 28-day period.

Main Outcomes and Measures

The primary outcome was occurrence of an unfavorable neurological outcome, defined as a Glasgow Outcome Scale Extended score between 1 and 5, at 180 days following randomization. There were 14 prespecified serious adverse events, including occurrence of cerebral ischemia after randomization.

Results

Among 820 patients who completed the trial (mean age, 51 years; 376 [45.9%] women), 806 had available data on the primary outcome, 393 in the liberal strategy group and 413 in the restrictive strategy group. The liberal strategy group received a median of 2 (IQR, 1-3) units of blood, and the restrictive strategy group received a median of 0 (IQR, 0-1) units of blood, with an absolute mean difference of 1.0 unit (95% CI, 0.87-1.12 units). At 180 days after randomization, 246 patients (62.6%) in the liberal strategy group had an unfavorable neurological outcome compared with 300 patients (72.6%) in the restrictive strategy group (absolute difference, -10.0% [95% CI, -16.5% to -3.6%]; adjusted relative risk, 0.86 [95% CI, 0.79-0.94]; P = .002). The effect of the transfusion thresholds on neurological outcome at 180 days was consistent across prespecified subgroups. In the liberal strategy group, 35 (8.8%) of 397 patients had at least 1 cerebral ischemic event compared with 57 (13.5%) of 423 in the restrictive strategy group (relative risk, 0.65 [95% CI, 0.44-0.97]).

Conclusions and Relevance

Patients with acute brain injury and anemia randomized to a liberal transfusion strategy were less likely to have an unfavorable neurological outcome than those randomized to a restrictive strategy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02968654.

Optimizing RBC Transfusion Strategies in Traumatic Brain Injury: Insights on Early Resuscitation and Cerebral Oxygenation

Effective early resuscitation and maintenance of brain oxygenation are critical for improving the outcomes of patients with severe traumatic brain injury (TBI). Red blood cell (RBC) transfusion plays a vital role in this process. Although RBC transfusion can enhance cerebral oxygenation and stabilize hemodynamics, it also poses significant risks including transfusion-related lung injury and transfusion-associated circulatory overload, highlighting the importance of meticulous transfusion management. This review explores transfusion strategies during the early resuscitation phase and the management of anemia in patients with severe TBI, focusing on appropriate treatment targets, utilizing monitoring-based personalized approaches, and summarizing recent research and current insights.

Liberal or Restrictive Transfusion Strategy in Patients with Traumatic Brain Injury

BACKGROUND

The effect of a liberal transfusion strategy as compared with a restrictive strategy on outcomes in critically ill patients with traumatic brain injury is unclear.

METHODS

We randomly assigned adults with moderate or severe traumatic brain injury and anemia to receive transfusion of red cells according to a liberal strategy (transfusions initiated at a hemoglobin level of ≤10 g per deciliter) or a restrictive strategy (transfusions initiated at ≤7 g per deciliter). The primary outcome was an unfavorable outcome as assessed by the score on the Glasgow Outcome Scale-Extended at 6 months, which we categorized with the use of a sliding dichotomy that was based on the prognosis of each patient at baseline. Secondary outcomes included mortality, functional independence, quality of life, and depression at 6 months.

RESULTS

A total of 742 patients underwent randomization, with 371 assigned to each group. The analysis of the primary outcome included 722 patients. The median hemoglobin level in the intensive care unit was 10.8 g per deciliter in the group assigned to the liberal strategy and 8.8 g per deciliter in the group assigned to the restrictive strategy. An unfavorable outcome occurred in 249 of 364 patients (68.4%) in the liberal-strategy group and in 263 of 358 (73.5%) in the restrictive-strategy group (adjusted absolute difference, restrictive strategy vs. liberal strategy, 5.4 percentage points; 95% confidence interval, -2.9 to 13.7). Among survivors, a liberal strategy was associated with higher scores on some but not all the scales assessing functional independence and quality of life. No association was observed between the transfusion strategy and mortality or depression. Venous thromboembolic events occurred in 8.4% of the patients in each group, and acute respiratory distress syndrome occurred in 3.3% and 0.8% of patients in the liberal-strategy and restrictive-strategy groups, respectively.

CONCLUSIONS

In critically ill patients with traumatic brain injury and anemia, a liberal transfusion strategy did not reduce the risk of an unfavorable neurologic outcome at 6 months. (Funded by the Canadian Institutes of Health Research and others; HEMOTION ClinicalTrials.gov number, NCT03260478.).

Low hemoglobin causes hematoma expansion and poor intracerebral hemorrhage outcomes

Objectives

Although lower hemoglobin levels associate with worse intracerebral hemorrhage (ICH) outcomes, causal drivers for this relationship remain unclear. We investigated the hypothesis that lower hemoglobin relates to increased hematoma expansion (HE) risk and poor outcomes using human observational data and assessed causal relationships using a translational murine model of anemia and ICH.

Methods

ICH patients with baseline hemoglobin measurements and serial CT neuroimaging enrolled between 2010-2016 to a multicenter, prospective observational cohort study were studied. Patients with systemic evidence of coagulopathy were excluded. Separate regression models assessed relationships of baseline hemoglobin with HE (≥33% and/or ≥6mL growth) and poor long-term neurological outcomes (modified Rankin Scale 4-6) after adjusting for relevant covariates. Using a murine collagenase ICH model with serial neuroimaging in anemic vs. non-anemic C57/BL6 mice, intergroup differences in ICH lesion volume, ICH volume changes, and early mortality were assessed.

Results

Among 1190 ICH patients analyzed, lower baseline hemoglobin levels associated with increased odds of HE (adjusted OR per -1g/dL hemoglobin decrement: 1.10 [1.02-1.19]) and poor 3-month clinical outcomes (adjusted OR per -1g/dL hemoglobin decrement: 1.11 [1.03-1.21]). Similar relationships were seen with poor 6 and 12-month outcomes. In our animal model, anemic mice had significantly greater ICH lesion expansion, final lesion volumes, and greater mortality, as compared to non-anemic mice.

Conclusions

These results, in a human cohort and a mouse model, provide novel evidence suggesting that anemia has causal roles in HE and poor ICH outcomes. Additional studies are required to clarify whether correcting anemia can improve these outcomes.

Anemia From Inflammation After Intracerebral Hemorrhage and Relationships With Outcome

BACKGROUND

Baseline anemia is associated with poor intracerebral hemorrhage (ICH) outcomes. However, underlying drivers for anemia and whether anemia development after ICH impacts clinical outcomes are unknown. We hypothesized that inflammation drives anemia development after ICH and assessed their relationship to outcomes.

METHODS AND RESULTS

Patients with serial hemoglobin and iron biomarker concentrations from the HIDEF (High-Dose Deferoxamine in Intracerebral Hemorrhage) trial were analyzed. Adjusted linear mixed models assessed laboratory changes over time. Of 42 patients, significant decrements in hemoglobin occurred with anemia increasing from 19% to 45% by day 5. Anemia of inflammation iron biomarker criteria was met in 88%. A separate cohort of 521 patients with ICH with more granular serial hemoglobin and long-term neurological outcome data was also investigated. Separate regression models assessed whether (1) systemic inflammatory response syndrome (SIRS) scores related to hemoglobin changes over time and (2) hemoglobin changes related to poor 90-day outcome. In this cohort, anemia prevalence increased from 30% to 71% within 2 days of admission yet persisted beyond this time. Elevated systemic inflammatory response syndrome was associated with greater hemoglobin decrements over time (adjusted parameter estimate: -0.27 [95% CI, -0.37 to -0.17]) and greater hemoglobin decrements were associated with poor outcomes (adjusted odds ratio per 1 g/dL increase, 0.76 [95% CI, 0.62-0.93]) independent to inflammation and ICH severity.

CONCLUSIONS

We identified novel findings that acute anemia development after ICH is common, rapid, and related to inflammation. Because anemia development is associated with poor outcomes, further work is required to clarify if anemia, or its underlying drivers, are modifiable treatment targets that can improve ICH outcomes.

REGISTRATION

https://www.clinicaltrials.gov Unique identifier: NCT01662895.

Adherence to a restrictive red blood cell transfusion strategy in critically ill patients: An observational study

BACKGROUND

Randomized controlled trials relatively consistently show that restrictive red blood cell (RBC) transfusion strategies are safe and associated with similar outcomes compared to liberal transfusion strategies in critically ill patients. Based on these data, the general threshold for RBC transfusion was changed to 70 g/L at a 9-bed tertiary level intensive care unit in September 2020. Implementation measures included lectures, webinars and feedback during clinical practice. The aim of this study was to investigate how implementation of a restrictive transfusion strategy influenced RBC usage, haemoglobin trigger levels and adherence to prescribed trigger levels.

METHODS

In this registry-based, observational study, critically ill adult patients without massive bleeding were included and divided into a pre-cohort, with admissions prior to the change of transfusion strategy, and a post-cohort, with admissions following the change of transfusion strategy. These cohorts were compared regarding key RBC transfusion-related variables.

RESULTS

In total 5626 admissions were included in the analyses (pre-cohort n = 4373, post-cohort n = 1253). The median volume (interquartile range, IQR) of RBC transfusions per 100 admission days, in the pre-cohort was 6120 (4110-8110) mL versus 3010 (2890-4970) mL in the post-cohort (p < .001). This corresponds to an estimated median saving of 1128 € per 100 admission days after a restrictive RBC transfusion strategy was implemented. In total, 26% of the admissions in the pre-cohort and 19% in the post-cohort (p < .001) received RBC transfusion(s) during days 0-10. Both median (IQR) prescribed trigger levels (determined by intensivist) and actual haemoglobin trigger levels (i.e., levels prior to actual administration of transfusion) were higher in the pre- versus post-cohort (90 [80-100] vs. 80 [72-90] g/L, p < .001 and 89 [82-96] g/L vs. 83 [79-94], p < .001, respectively). Percentage of days without compliance with the prescribed transfusion trigger was higher in the pre-cohort than in the post-cohort (23% vs. 14%, p < .001). Sensitivity analyses, excluding patients with traumatic brain injury, ischemic heart disease and COVID-19 demonstrated similar results.

CONCLUSIONS

Implementation of a restrictive transfusion trigger in a critical care setting resulted in lasting decreased RBC transfusion use and costs, decreased prescribed and actual haemoglobin trigger levels and improved adherence to prescribed haemoglobin trigger levels.

Haemoglobin values, transfusion practices, and long-term outcomes in critically ill patients with traumatic brain injury: a secondary analysis of CENTER-TBI

Haemoglobin (Hb) thresholds and red blood cells (RBC) transfusion strategies in traumatic brain injury (TBI) are controversial. Our objective was to assess the association of Hb values with long-term outcomes in critically ill TBI patients. We conducted a secondary analysis of CENTER-TBI, a large multicentre, prospective, observational study of European TBI patients. All patients admitted to the Intensive Care Unit (ICU) with available haemoglobin data on admission and during the first week were included. During the first seven days, daily lowest haemoglobin values were considered either a continous variable or categorised as < 7.5 g/dL, between 7.5-9.5 and > 9.5 g/dL. Anaemia was defined as haemoglobin value < 9.5 g/dL. Transfusion practices were described as "restrictive" or "liberal" based on haemoglobin values before transfusion (e.g. < 7.5 g/dL or 7.5-9.5 g/dL). Our primary outcome was the Glasgow outcome scale extended (GOSE) at six months, defined as being unfavourable when < 5. Of 1590 included, 1231 had haemoglobin values available on admission. A mean Injury Severity Score (ISS) of 33 (SD 16), isolated TBI in 502 (40.7%) and a mean Hb value at ICU admission of 12.6 (SD 2.2) g/dL was observed. 121 (9.8%) patients had Hb < 9.5 g/dL, of whom 15 (1.2%) had Hb < 7.5 g/dL. 292 (18.4%) received at least one RBC transfusion with a median haemoglobin value before transfusion of 8.4 (IQR 7.7-8.5) g/dL. Considerable heterogeneity regarding threshold transfusion was observed among centres. In the multivariable logistic regression analysis, the increase of haemoglobin value was independently associated with the decrease in the occurrence of unfavourable neurological outcomes (OR 0.78; 95% CI 0.70-0.87). Congruous results were observed in patients with the lowest haemoglobin values within the first 7 days < 7.5 g/dL (OR 2.09; 95% CI 1.15-3.81) and those between 7.5 and 9.5 g/dL (OR 1.61; 95% CI 1.07-2.42) compared to haemoglobin values > 9.5 g/dL. Results were consistent when considering mortality at 6 months as an outcome. The increase of hemoglobin value was associated with the decrease of mortality (OR 0.88; 95% CI 0.76-1.00); haemoglobin values less than 7.5 g/dL was associated with an increase of mortality (OR 3.21; 95% CI 1.59-6.49). Anaemia was independently associated with long-term unfavourable neurological outcomes and mortality in critically ill TBI patients.Trial registration: CENTER-TBI is registered at ClinicalTrials.gov, NCT02210221, last update 2022-11-07.

Anemia and Optimal Transfusion Thresholds in Brain-Injured Patients: A Narrative Review of the Literature

Anemia is a highly prevalent condition that may compromise oxygen delivery to vital organs, especially among the critically ill. Although current evidence supports the adoption of a restrictive transfusion strategy and threshold among the nonbleeding critically ill patient, it remains unclear whether this practice should apply to the brain-injured patient, given the predisposition to cerebral ischemia in this patient population, in which even nonprofound anemia may exert a detrimental effect on clinical outcomes. The purpose of this review is to provide an overview of the pathophysiological changes related to impaired cerebral oxygenation in the brain-injured patient and to present the available evidence on the effect of anemia and varying transfusion thresholds on the clinical outcomes of patients with acute brain injury.

Red blood cell transfusion in neurocritical patients: a systematic review and meta-analysis

BACKGROUND

Anemia can lead to secondary brain damage by reducing arterial oxygen content and brain oxygen supply. Patients with acute brain injury have impaired self-regulation. Brain hypoxia may also occur even in mild anemia. Red blood cell (RBC) transfusion is associated with increased postoperative complications, poor neurological recovery, and mortality in critically ill neurologic patients. Balancing the risks of anemia and red blood cell transfusion-associated adverse effects is challenging in neurocritical settings.

METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE (PubMed) from inception to January 31, 2024. We included all randomized controlled trials (RCTs) assessing liberal versus restrictive RBC transfusion strategies in neurocritical patients. We included all relevant studies published in English. The primary outcome was mortality at intensive care unit (ICU), discharge, and six months.

RESULTS

Of 5195 records retrieved, 84 full-text articles were reviewed, and five eligible studies were included. There was no significant difference between the restrictive and liberal transfusion groups in ICU mortality (RR: 2.53, 95% CI: 0.53 to 12.13), in-hospital mortality (RR: 2.34, 95% CI: 0.50 to 11.00), mortality at six months (RR: 1.42, 95% CI: 0.42 to 4.78) and long-term mortality (RR: 1.22, 95% CI: 0.64 to 2.33). The occurrence of neurological adverse events and most major non-neurological complications was similar in the two groups. The incidence of deep venous thrombosis was lower in the restrictive strategy group (RR: 0.41, 95% CI: 0.18 to 0.91).

CONCLUSIONS

Due to the small sample size of current studies, the evidence is insufficiently robust to confirm definitive conclusions for neurocritical patients. Therefore, further investigation is encouraged to define appropriate RBC transfusion thresholds in the neurocritical setting.

The management of severe traumatic brain injury in the initial postinjury hours - current evidence and controversies

PURPOSE OF REVIEW

To provide an overview of recent studies discussing novel strategies, controversies, and challenges in the management of severe traumatic brain injury (sTBI) in the initial postinjury hours.

RECENT FINDINGS

Prehospital management of sTBI should adhere to Advanced Trauma Life Support (ATLS) principles. Maintaining oxygen saturation and blood pressure within target ranges on-scene by anesthetist, emergency physician or trained paramedics has resulted in improved outcomes. Emergency department (ED) management prioritizes airway control, stable blood pressure, spinal immobilization, and correction of impaired coagulation. Noninvasive techniques such as optic nerve sheath diameter measurement, pupillometry, and transcranial Doppler may aid in detecting intracranial hypertension. Osmotherapy and hyperventilation are effective as temporary measures to reduce intracranial pressure (ICP). Emergent computed tomography (CT) findings guide surgical interventions such as decompressive craniectomy, or evacuation of mass lesions. There are no neuroprotective drugs with proven clinical benefit, and steroids and hypothermia cannot be recommended due to adverse effects in randomized controlled trials.

SUMMARY

Advancement of the prehospital and ED care that include stabilization of physiological parameters, rapid correction of impaired coagulation, noninvasive techniques to identify raised ICP, emergent surgical evacuation of mass lesions and/or decompressive craniectomy, and temporary measures to counteract increased ICP play pivotal roles in the initial management of sTBI. Individualized approaches considering the underlying pathology are crucial for accurate outcome prediction.

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.

Red Blood Cell Transfusions Are Not Associated With Incident Complications or Poor Outcomes in Patients With Intracerebral Hemorrhage

Background Anemia is associated with poor intracerebral hemorrhage (ICH) outcomes, yet the relationship of red blood cell (RBC) transfusions to ICH complications and functional outcomes remains unclear. We investigated the impact of RBC transfusion on hospital thromboembolic and infectious complications and outcomes in patients with ICH. Methods and Results Consecutive patients with spontaneous ICH enrolled in a single-center, prospective cohort study from 2009 to 2018 were assessed. Primary analyses assessed relationships of RBC transfusions on incident thromboembolic and infectious complications occurring after the transfusion. Secondary analyses assessed relationships of RBC transfusions with mortality and poor discharge modified Rankin Scale score 4 to 6. Multivariable logistic regression models adjusted for baseline demographics and medical disease severity (Acute Physiology and Chronic Health Evaluation II), and ICH severity (ICH score).Of 587 patients with ICH analyzed, 88 (15%) received at least one RBC transfusion. Patients receiving RBC transfusions had worse medical and ICH severity. Though patients receiving RBC transfusions had more complications at any point during the hospitalization (64.8% versus 35.9%), we found no association between RBC transfusion and incident complications in our regression models (adjusted odds ratio [aOR], 0.71 [95% CI, 0.42-1.20]). After adjusting for disease severity and other relevant covariates, we found no significant association between RBC transfusion and mortality (aOR, 0.87 [95% CI, 0.45-1.66]) or poor discharge modified Rankin Scale score (aOR, 2.45 [95% CI, 0.80-7.61]). Conclusions In our cohort with ICH, RBC transfusions were expectedly given to patients with higher medical and ICH severity. Taking disease severity and timing of transfusions into account, RBC transfusion was not associated with incident hospital complications or poor clinical ICH outcomes.

Patient Blood Management, Anemia, and Transfusion Optimization Across Surgical Specialties

Patient blood management (PBM) is a systematic, evidence-based approach to improve patient outcomes by managing and preserving a patient's own blood and minimizing allogenic transfusion need and risk. According to the PBM approach, the goals of perioperative anemia management include early diagnosis, targeted treatment, blood conservation, restrictive transfusion except in cases of acute and massive hemorrhage, and ongoing quality assurance and research efforts to advance overall blood health.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

TRansfusion strategies in Acute brain INjured patients (TRAIN): a prospective multicenter randomized interventional trial protocol

BACKGROUND

Although blood transfusions can be lifesaving in severe hemorrhage, they can also have potential complications. As anemia has also been associated with poor outcomes in critically ill patients, determining an optimal transfusion trigger is a real challenge for clinicians. This is even more important in patients with acute brain injury who were not specifically evaluated in previous large randomized clinical trials. Neurological patients may be particularly sensitive to anemic brain hypoxia because of the exhausted cerebrovascular reserve, which adjusts cerebral blood flow to tissue oxygen demand.

METHODS

We described herein the methodology of a prospective, multicenter, randomized, pragmatic trial comparing two different strategies for red blood cell transfusion in patients with acute brain injury: a "liberal" strategy in which the aim is to maintain hemoglobin (Hb) concentrations greater than 9 g/dL and a "restrictive" approach in which the aim is to maintain Hb concentrations greater than 7 g/dL. The target population is patients suffering from traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), or intracerebral hemorrhage (ICH). The primary outcome is the unfavorable neurological outcome, evaluated using the extended Glasgow Outcome Scale (eGOS) of 1-5 at 180 days after the initial injury. Secondary outcomes include, among others, 28-day survival, intensive care unit (ICU) and hospital lengths of stay, the occurrence of extra-cerebral organ dysfunction/failure, and the development of any infection or thromboembolic events. The estimated sample size is 794 patients to demonstrate a reduction in the primary outcome from 50 to 39% between groups (397 patients in each arm). The study was initiated in 2016 in several ICUs and will be completed in December 2022.

DISCUSSION

This trial will assess the impact of a liberal versus conservative strategy of blood transfusion in a large cohort of critically ill patients with a primary acute brain injury. The results of this trial will help to improve blood product and transfusion use in this specific patient population and will provide additional data in some subgroups of patients at high risk of brain ischemia, such as those with intracranial hypertension or cerebral vasospasm.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02968654.

Management of moderate to severe traumatic brain injury: an update for the intensivist

Traumatic brain injury (TBI) remains one of the most fatal and debilitating conditions in the world. Current clinical management in severe TBI patients is mainly concerned with reducing secondary insults and optimizing the balance between substrate delivery and consumption. Over the past decades, multimodality monitoring has become more widely available, and clinical management protocols have been published that recommend potential interventions to correct pathophysiological derangements. Even while evidence from randomized clinical trials is still lacking for many of the recommended interventions, these protocols and algorithms can be useful to define a clear standard of therapy where novel interventions can be added or be compared to. Over the past decade, more attention has been paid to holistic management, in which hemodynamic, respiratory, inflammatory or coagulation disturbances are detected and treated accordingly. Considerable variability with regards to the trajectories of recovery exists. Even while most of the recovery occurs in the first months after TBI, substantial changes may still occur in a later phase. Neuroprognostication is challenging in these patients, where a risk of self-fulfilling prophecies is a matter of concern. The present article provides a comprehensive and practical review of the current best practice in clinical management and long-term outcomes of moderate to severe TBI in adult patients admitted to the intensive care unit.

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 Guidelines in Traumatic Brain Injury: A Systematic Review and Meta-Analysis of the Currently Available Evidence

Our study aims to provide a synthesis of the best available evidence on the hemoglobin (hgb) red blood cell (RBC) transfusion thresholds in adult traumatic brain injury (TBI) patients, as well as describing the risk factors and outcomes associated with RBC transfusion in this population. A systematic review and meta-analysis was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess articles discussing RBC transfusion thresholds and describe complications secondary to transfusion in adult TBI patients in the perioperative period. Fifteen articles met search criteria and were reviewed for analysis. Compared to non-transfused, TBI patients who received transfusion tended to be primarily male patients with worse Injury Severity Score (ISS) and Glasgow Coma Scale. Further, the meta-analysis corroborated that transfused TBI patients are older (p = 0.04), have worse ISS scores (p = 0.001), receive more units of RBCs (p = 0.02), and have both higher mortality (p < 0.001) and complication rates (p < 0.0001). There were no differences identified in rates of hypertension, diabetes mellitus, and Abbreviated Injury Scale scores. Additionally, whereas many studies support restrictive (hgb <7 g/dL) transfusion thresholds over liberal (hgb <10 g/dL), our meta-analysis revealed no significant difference in mortality between those thresholds (p = 0.79). Current Class B/C level III evidence predominantly recommends against a liberal transfusion threshold of 10 g/dL for TBI patients (Class B/C level III), but our meta-analysis found no difference in survival between groups. There is evidence suggesting that an intermediate threshold between 7 and 9 g/dL, reflecting the physiological oxygen needs of cerebral tissue, may be worth exploring.

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.

A Retrospective Analysis of Randomized Controlled Trials on Traumatic Brain Injury: Evaluation of CONSORT Item Adherence

Traumatic brain injury (TBI) contributes to death and disability, resulting in an enormous individual and socio-economic challenges. Despite huge efforts, there are still controversies on treatment strategies and early outcome estimation. We evaluate current randomized controlled trials (RCTs) on TBI according to their fulfillment of the CONSORT (Consolidated Statement of Reporting Trials) statement’s criteria as a marker of transparency and the quality of study planning and realization. A PubMed search for RCTs on TBI (January 2014–December 2019) was carried out. After screening of the abstracts (n = 1.926), the suitable full text manuscripts (n = 72) were assessed for the fulfillment of the CONSORT criteria. The mean ratio of consort statement fulfillment was 59% (±13%), 31% of the included studies (n = 22) complied with less than 50% of the CONSORT criteria. Citation frequency was moderately related to ratio of CONSORT item fulfillment (r = 0.4877; p < 0.0001) and citation frequency per year (r = 0.5249; p < 0.0001). The ratio of CONSORT criteria fulfillment was associated with the impact factor of the publishing journal (r = 0.6428; p < 0.0001). Essential data for study interpretation, such as sample size determination (item 7a), participant flow (item 13a) as well as losses and exclusions (item 13b), were only reported in 53%, 60% and 63%, respectively. Reporting and methodological aspects in RCTs on TBI still may be improved. Thus, the interpretation of study results may be hampered due to methodological weaknesses.

Hemoglobin levels as a transfusion criterion in moderate to severe traumatic brain injury: a systematic review and meta-analysis

BACKGROUND

Several factors can influence the outcome of severe head injuries including the patient's hemoglobin levels. There has often been a dilemma regarding levels of hemoglobin at which red cell blood transfusion (RCBT) should be performed.

OBJECTIVE

To systematically review the literature to determine the usefulness of management protocols that have hemoglobin levels <10 g/dL vs <7 g/dL as an RCBT criterion.

METHODS

Following the PRISMA statement, the search was constructed using terms and descriptors of the Medical Subject Heading (MeSH), combined with Boolean operators. Full text of these articles was studied, and outcome measures at 3-6 months were considered for patients who were given a RCBT at <10 g/dL or at 7 g/dL hemoglobin levels.

RESULTS

A total of 4 articles were found suitable for inclusion in the meta-analysis. RCBT below 7 g/dL was not associated with an increased risk of mortality as compared to RCBT using the value of less than 10 g/dL. RCBT at lower levels of hemoglobin was also not associated with a poor neurological outcome (GOS 4-5) but rather RCBT at lower levels lead to better outcomes (GOS 1-3) and the association was significant.

CONCLUSION

Allogenic RCBT was associated with poorer neurological outcomes, within a wide range of reported differences in the hemoglobin threshold to decide for RCBT in TBI patients. Restrictive RCBT strategy may be useful in moderate to severe TBI cases although the risk of anemia-induced cerebral injury needs further investigation regarding the risks and complications inherent to RCBT.

Red blood cell transfusion in animal models of acute brain injuries: a systematic review protocol

BACKGROUND

Anemia is common in neurocritically ill patients. Considering the limited clinical evidence in this population, preclinical data may provide some understanding of the potential impact of anemia and of red blood cell transfusion in these patients. We aim to estimate the association between different transfusion strategies and neurobehavioral outcome in animal models.

METHODS

We will conduct a systematic review of comparative studies of red blood cell transfusion strategies using animal models of traumatic brain injury, ischemic stroke or cerebral hemorrhage. We will search MEDLINE, EMBASE, and Web of Science databases for eligible studies from inception onwards. Two independent reviewers will perform study selection and data extraction. We will report our results in a descriptive synthesis focusing on characteristics of included studies, reported outcomes, risk of bias, and construct validity. Our primary outcome is the neurological function (neurobehavioral performance) and our secondary outcomes include mortality, infarct size, intracranial pressure, cerebral perfusion pressure, cerebral blood flow, and brain tissue oxygen tension. If appropriate, we will also perform a quantitative synthesis and pool results using random-effect models. Heterogeneity will be expressed with I² statistics. Subgroup analyses are planned according to animal model characteristics, co-interventions, and risks of bias.

DISCUSSION

Our study is aligned with the efforts to better understand the level of evidence on the impact of red blood cell transfusion strategies from preclinical studies in animal models of acute brain injury and the potential translation of information from the preclinical to the clinical research field.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018086662 .

Fine Tuning of Traumatic Brain Injury Management in Neurointensive Care-Indicative Observations and Future Perspectives

Neurointensive care (NIC) has contributed to great improvements in clinical outcomes for patients with severe traumatic brain injury (TBI) by preventing, detecting, and treating secondary insults and thereby reducing secondary brain injury. Traditional NIC management has mainly focused on generally applicable escalated treatment protocols to avoid high intracranial pressure (ICP) and to keep the cerebral perfusion pressure (CPP) at sufficiently high levels. However, TBI is a very heterogeneous disease regarding the type of injury, age, comorbidity, secondary injury mechanisms, etc. In recent years, the introduction of multimodality monitoring, including, e.g., pressure autoregulation, brain tissue oxygenation, and cerebral energy metabolism, in addition to ICP and CPP, has increased the understanding of the complex pathophysiology and the physiological effects of treatments in this condition. In this article, we will present some potential future approaches for more individualized patient management and fine-tuning of NIC, taking advantage of multimodal monitoring to further improve outcome after severe TBI.