Red blood cell transfusion in acute brain injury subtypes: An observational cohort study

Need for Blood Transfusion Volume Is Associated With Increased Mortality in Severe Traumatic Brain Injury

INTRODUCTION

Many patients suffering from isolated severe traumatic brain injury (sTBI) receive blood transfusion on hospital arrival due to hypotension. We hypothesized that increasing blood transfusions in isolated sTBI patients would be associated with an increase in mortality.

METHODS

We performed a trauma quality improvement program (TQIP) (2017-2019) and single-center (2013-2021) database review filtering for patients with isolated sTBI (Abbreviated Injury Scale head ≥3 and all other areas ≤2). Age, initial Glasgow Coma Score (GCS), Injury Severity Score (ISS), initial systolic blood pressure (SBP), mechanism (blunt/penetrating), packed red blood cells (pRBCs) and fresh frozen plasma (FFP) transfusion volume (units) within the first 4 h, FFP/pRBC ratio (4h), and in-hospital mortality were obtained from the TQIP Public User Files.

RESULTS

In the TQIP database, 9257 patients had isolated sTBI and received pRBC transfusion within the first 4 h. The mortality rate within this group was 47.3%. The increase in mortality associated with the first unit of pRBCs was 20%, then increasing approximately 4% per unit transfused to a maximum mortality of 74% for 11 or more units. When adjusted for age, initial GCS, ISS, initial SBP, and mechanism, pRBC volume (1.09 [1.08-1.10], FFP volume (1.08 [1.07-1.09]), and FFP/pRBC ratio (1.18 [1.08-1.28]) were associated with in-hospital mortality. Our single-center study yielded 138 patients with isolated sTBI who received pRBC transfusion. These patients experienced a 60.1% in-hospital mortality rate. Logistic regression corrected for age, initial GCS, ISS, initial SBP, and mechanism demonstrated no significant association between pRBC transfusion volume (1.14 [0.81-1.61]), FFP transfusion volume (1.29 [0.91-1.82]), or FFP/pRBC ratio (6.42 [0.25-164.89]) and in-hospital mortality.

CONCLUSIONS

Patients suffering from isolated sTBI have a higher rate of mortality with increasing amount of pRBC or FFP transfusion within the first 4 h of arrival.

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.

Anemia and Red Blood Cell Transfusion in Aneurysmal Subarachnoid Hemorrhage

Anemia is very common in aneurysmal subarachnoid hemorrhage (aSAH), with approximately half of the aSAH patient population developing moderate anemia during their hospital stay. The available evidence (both physiologic and clinical) generally supports an association of anemia with unfavorable outcomes. Although aSAH shares a number of common mechanisms of secondary insult with other forms of acute brain injury, aSAH also has specific features that make it unique: an early phase (in which early brain injury predominates) and a delayed phase (in which delayed cerebral ischemia and vasospasm predominate). The effects of both anemia and transfusion are potentially variable between these phases, which may have unique considerations and possibly different risk-benefit profiles. Data on transfusion in this population are almost exclusively limited to observational studies, which suffer from significant heterogeneity and risk of bias. Overall, the results are conflicting, with the balance of the studies suggesting that transfusion is associated with unfavorable outcomes. The transfusion targets that are well established in other critically ill populations should not be automatically applied to patients with aSAH because of the unique disease characteristics of this population and the limited representation of aSAH in the clinical trials that established these targets. There are two upcoming clinical trials evaluating transfusion in aSAH that should help clarify specific transfusion targets. Until then, it is reasonable to base transfusion decisions on the current guidelines and use an individualized approach incorporating physiologic and clinical data when available.

Postoperative Transfusion Guidelines in Aneurysmal Cerebral Subarachnoid Hemorrhage: A Systematic Review and Critical Summary of Available Evidence

OBJECTIVE

Surgical management of aneurysmal subarachnoid hemorrhage (SAH) often involves red blood cell (RBC) transfusion, which increases the risk of postoperative complications. RBC transfusion guidelines report on chronically critically ill patients and may not apply to patients with SAH. Our study aims to synthesize the evidence to recommend RBC transfusion thresholds among adult patients with SAH undergoing surgery.

METHODS

A systematic review was conducted using PubMed, Google Scholar, and Web of Science electronic databases according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to critically assess primary articles discussing RBC transfusion thresholds and describe complications secondary to RBC transfusion in adult patients with SAH in the perioperative period.

RESULTS

Sixteen articles meeting our search strategy were reviewed. Patients with SAH who received blood transfusion were older, female, had World Federation of Neurosurgical Societies grade IV-V and modified Fisher grade 3-4 scores, and presented with more comorbidities such as hypertension, diabetes, and cardiovascular and pulmonary diseases. In addition, transfusion was associated with multiple postoperative complications, including higher rates of vasospasms, surgical site infections, cardiovascular and respiratory complications, increased postoperative length of stay, and 30-day mortality. Analysis of transfused patients showed that a higher hemoglobin (>10 g/dL) goal after SAH was safe and that patients may benefit from a higher whole hospital stay hemoglobin nadir, as shown by a reduction in risk of cerebral vasospasm and improvement in clinical outcomes (level B class II).

CONCLUSIONS

Among patients with SAH, the benefits of reducing cerebral ischemia and anemia are shown to outweigh the risks of transfusion-related complications.

Contribution of Various Types of Transfusion to Acute and Delayed Intracerebral Hemorrhage Injury

Intracerebral hemorrhage (ICH) is the second most prevalent type of stroke, after ischemic stroke, and has exceptionally high morbidity and mortality rates. After spontaneous ICH, one primary goal is to restrict hematoma expansion, and the second is to limit brain edema and secondary injury. Various types of transfusion therapies have been studied as treatment options to alleviate the adverse effects of ICH etiopathology. The objective of this work is to review transfusions with platelets, fresh frozen plasma (FFP), prothrombin complex concentrate (PCC), and red blood cells (RBCs) in patients with ICH. Furthermore, tranexamic acid infusion studies have been included due to its connection to ICH and hematoma expansion. As stated, the first line of therapy is limiting bleeding in the brain and hematoma expansion. Platelet transfusion is used to promote recovery and mitigate brain damage, notably in patients with severe thrombocytopenia. Additionally, tranexamic acid infusion, FFP, and PCC transfusion have been shown to affect hematoma expansion rate and volume. Although there is limited available research, RBC transfusions have been shown to cause higher tissue oxygenation and lower mortality, notably after brain edema, increases in intracranial pressure, and hypoxia. However, these types of transfusion have varied results depending on the patient, hemostasis status/blood thinner, hemolysis, anemia, and complications, among other variables. Inconsistencies in published results on various transfusion therapies led us to review the data and discuss issues that need to be considered when establishing future guidelines for patients with ICH.

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 .

Precision Medicine in Acute Brain Injury: A Narrative Review

Over the past few years, the concept of personalized medicine has percolated into the management of different neurological conditions. Improving outcomes after acute brain injury (ABI) continues to be a major challenge. Unrecognized individual multiomic variations in addition to multiple interacting processes may explain why we fail to observe comprehensive improvements in ABI outcomes even when applied treatments appear to be beneficial logically. The provision of clinical care based on a multiomic approach may revolutionize the management of traumatic brain injury, delayed cerebral ischemia after subarachnoid hemorrhage, acute ischemic stroke, and several other neurological diseases. The challenge is to incorporate all the information obtained from genomic studies, other omic data, and individual variability into a practical tool that can be used to assist clinical decision-making. The effective execution of such strategies, which is still far away, requires the development of protocols on the basis of these complex interactions and strict adherence to management protocols. In this review, we will discuss various omics and physiological targets to guide individualized patient management after ABI.

Timing of Transfusion, not Hemoglobin Variability, is Associated with 3-Month Outcomes in Acute Ischemic Stroke

Objectives: This study aimed to investigate whether transfusions and hemoglobin variability affects the outcome of stroke after an acute ischemic stroke (AIS).

METHODS

We studied consecutive patients with AIS admitted in three tertiary hospitals who received red blood cell (RBC) transfusion (RBCT) during admission. Hemoglobin variability was assessed by minimum, maximum, range, median absolute deviation, and mean absolute change in hemoglobin level. Timing of RBCT was grouped into two categories: admission to 48 h (early) or more than 48 h (late) after hospitalization. Late RBCT was entered into multivariable logistic regression model. Poor outcome at three months was defined as a modified Rankin Scale score ≥3.

RESULTS

Of 2698 patients, 132 patients (4.9%) received a median of 400 mL (interquartile range: 400-840 mL) of packed RBCs. One-hundred-and-two patients (77.3%) had poor outcomes. The most common cause of RBCT was gastrointestinal bleeding (27.3%). The type of anemia was not associated with the timing of RBCT. Late RBCT was associated with poor outcome (odd ratio (OR), 3.55; 95% confidence interval (CI), 1.43-8.79; p-value = 0.006) in the univariable model. After adjusting for age, sex, Charlson comorbidity index, and stroke severity, late RBCT was a significant predictor (OR, 3.37; 95% CI, 1.14-9.99; p-value = 0.028) of poor outcome at three months. In the area under the receiver operating characteristics curve comparison, addition of hemoglobin variability indices did not improve the performance of the multivariable logistic model.

CONCLUSION

Late RBCT, rather than hemoglobin variability indices, is a predictor for poor outcome in patients with AIS.