Liberal or Restrictive Transfusion Strategy in Aneurysmal Subarachnoid Hemorrhage

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.

Restrictive RBC Transfusion in the ICU: Trends in Clinical Adherence

INTRODUCTION

The balance between the risks and benefits of red blood cell (RBC) transfusions in critically ill patients is of ongoing debate. Clinical guidelines suggest a restrictive transfusion strategy with a transfusion hemoglobin trigger of 7 g/dL for most critically ill patients. However, recent literature shows many RBC transfusions are given with a prior hemoglobin above 7 g/dL. We aimed to evaluate adherence to our own transfusion protocol and changes in transfusion policy over time for the entire Intensive Care Unit (ICU) and in subgroups.

METHODS

Retrospective observational cohort study of patients admitted between 2017 and 2024 to the ICU of Amsterdam UMC. Data was extracted from the electronic health record and the Dutch national quality registry (NICE). Subgroup analysis was done based on referring specialty.

RESULTS

In total 24 761 ICU stays were analyzed with 12 064 RBC transfusions in 3444 ICU stays. Median hemoglobin value before RBC transfusion decreased from 7.7 g/dL (1st-3rd quartile 7.1 - 8.4) in 2017 to 6.8 g/dL ((1st-3rd quartile 6.4 - 7.3) in 2024 (p<0.001). This decrease was present in all subgroups. The percentage of RBC transfusions with a prior hemoglobin <7 g/dL increased from 18.8% to 64.8% (p<0.001).

CONCLUSION

We report the long term successful implementation of a comprehensive restrictive RBC transfusion protocol in a tertiary care ICU, independent of the patient's referring specialty. A median hemoglobin level of 6.8 g/dL before RBC transfusion was reached in 2024.

Current Management of Aneurysmal Subarachnoid Hemorrhage

The diagnosis of aneurysmal subarachnoid hemorrhage (aSAH) is most difficult in patients who are in good clinical condition with a small hemorrhage, especially when a ruptured aneurysm might not be considered, or if a computed tomographic (CT) scan is not obtained, or if when a CT is obtained, the findings are subtle and missed by an inexperienced reviewer. All acute onset (thunderclap) headaches should be considered ruptured aneurysms until proven otherwise. Treatment begins with immediate control of pain and blood pressure, placement of an external ventricular drain (EVD) in poor-grade patients and those with acute hydrocephalus on CT scanning, administration of antifibrinolytic tranexamic acid, and then repair of the aneurysm with either surgical clipping or endovascular techniques as soon as the appropriate treatment team can be assembled. After securing the aneurysm, aSAH patient treatment is focused on maintaining euvolemia and a favorable systemic metabolic state for brain repair. A significant and aneurysm-specific threat after aSAH is delayed arterial vasospasm and resulting cerebral ischemia, which is detected by vigilant bedside examinations for new-onset focal deficits or neurological decline, assisted with daily transcranial Doppler examinations and the judicious use of vascular imaging and cerebral perfusion studies with CT. The management of diagnosed symptomatic vasospasm is the prompt induction of hypertension with vasopressors, but if this fails to reverse deficits quickly after reaching a target systolic blood pressure of 200 mmHg, endovascular angioplasty is indicated, providing CT scanning rules out an established cerebral infarction. Balloon angioplasty should be considered early for all patients found to have severe angiographic vasospasm, with or without detectable signs of ischemic neurological deterioration due to either sedation or a pre-existing deficit.

Liberal versus restrictive transfusion strategies in subarachnoid hemorrhage: a secondary analysis of the TRAIN study

BACKGROUND

The optimal hemoglobin (Hb) threshold to trigger red blood cell transfusions (RBCT) in subarachnoid hemorrhage (SAH) patients is unclear. This study evaluated the impact of liberal versus restrictive transfusion strategies on neurological outcome in patients with SAH.

METHODS

This is a pre-planned secondary analysis of the "TRansfusion Strategies in Acute brain INjured Patients" (TRAIN) study. We included all SAH patients from the original study that were randomized to receive RBCT when Hb levels dropped below 9 g/dL (liberal group) or 7 g/dL (restrictive group). The primary outcome was an unfavorable neurological outcome at 180 days, defined by a Glasgow Outcome Scale Extended score of 1-5.

RESULTS

Of the 190 SAH patients in the trial, 188 (98.9%) had data available for the primary outcome, with 86 (45.3%) in the liberal group and 102 (53.6%) in the restrictive group. Patients in the liberal group were older than in the restrictive group, but otherwise had similar baseline characteristics. Patients in the liberal group received more RBCT and showed higher Hb levels over time. At 180 days, 57 (66.3%) patients in the liberal group and 78 (76.4%) in the restrictive group had unfavorable outcomes (risk ratio, RR 0.87; 95% confidence intervals, 95% CI 0.71-1.04). Patients in the liberal group had a significantly lower risk of cerebral ischemia (RR 0.63; 95% CI 0.41-0.97). In a multivariate analysis, randomization to the liberal group was associated with a lower risk of unfavorable outcome (RR 0.83, 95% CI 0.70-0.99).

CONCLUSIONS

A liberal transfusion strategy was not associated with a lower incidence of unfavorable outcome after SAH when compared to a restrictive strategy. However, in a multivariable analysis adjusted for confounders randomization to the liberal group was associated with lower risk of unfavorable outcome. The occurrence of cerebral ischemia was significantly lower in the liberal transfusion strategy group.

TRIAL REGISTRATION

ClinicalTrials.gov number-NCT02968654 registered on November 16th, 2016.

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.