Anemia and red blood cell transfusion in neurocritical care

Discovery of generalizable TBI phenotypes using multivariate time-series clustering

Traumatic Brain Injury (TBI) presents a broad spectrum of clinical presentations and outcomes due to its inherent heterogeneity, leading to diverse recovery trajectories and varied therapeutic responses. While many studies have delved into TBI phenotyping for distinct patient populations, identifying TBI phenotypes that consistently generalize across various settings and populations remains a critical research gap. Our research addresses this by employing multivariate time-series clustering to unveil TBI's dynamic intricates. Utilizing a self-supervised learning-based approach to clustering multivariate time-Series data with missing values (SLAC-Time), we analyzed both the research-centric TRACK-TBI and the real-world MIMIC-IV datasets. Remarkably, the optimal hyperparameters of SLAC-Time and the ideal number of clusters remained consistent across these datasets, underscoring SLAC-Time's stability across heterogeneous datasets. Our analysis revealed three generalizable TBI phenotypes (α, β, and γ), each exhibiting distinct non-temporal features during emergency department visits, and temporal feature profiles throughout ICU stays. Specifically, phenotype α represents mild TBI with a remarkably consistent clinical presentation. In contrast, phenotype β signifies severe TBI with diverse clinical manifestations, and phenotype γ represents a moderate TBI profile in terms of severity and clinical diversity. Age is a significant determinant of TBI outcomes, with older cohorts recording higher mortality rates. Importantly, while certain features varied by age, the core characteristics of TBI manifestations tied to each phenotype remain consistent across diverse populations.

Association of Fluid Balance and Hemoglobin Decline With Neurological Outcome After Aneurysmal Subarachnoid Hemorrhage

OBJECTIVES

To explore the relationship between fluid balance and hemoglobin decline with secondary infarctions and neurologic outcome in aneurysmal subarachnoid hemorrhage (aSAH) patients.

DESIGN

Secondary analysis of the Earlydrain trial, a prospective randomized controlled study investigating prophylactic lumbar drain use in aSAH patients.

SETTING

Patients with aSAH treated in ICUs at 19 tertiary hospitals in Germany, Switzerland, and Canada.

PATIENTS

From January 2011 to January 2016, 287 patients were enrolled in the Earlydrain trial. Only files with complete information on both daily hemoglobin and balance values were used, leaving 237 patients for analysis.

INTERVENTIONS

Investigation of fluid balance management and hemoglobin levels during the initial 8 days post-aSAH to establish thresholds for unfavorable outcomes and assess their impact on secondary infarctions and 6-month neurologic outcome on the modified Rankin Scale (mRS).

MEASUREMENTS AND MAIN RESULTS

Patients with unfavorable outcome after 6 months (mRS > 2) showed greater hemoglobin decline and increased cumulative fluid balance. A significant inverse relationship existed between fluid balance and hemoglobin decline. Thresholds for unfavorable outcome were 10.4 g/dL hemoglobin and 4894 mL cumulative fluid balance in the first 8 days. In multivariable analysis, fluid balance, but not fluid intake, remained significantly associated with unfavorable outcome, while the influence of hemoglobin lessened. Fluid balance but not hemoglobin related to secondary infarctions, with the effect being significant after inverse probability of treatment weighting. Transfusion was associated with unfavorable outcomes.

CONCLUSIONS

Increased fluid balance influences hemoglobin decline through hemodilution. Fluid overload, rather than a slight decrease in hemoglobin levels, appears to be the primary factor contributing to poor outcomes in aSAH patients. The results suggest aiming for euvolemia and that a modest hemoglobin decline may be tolerated. It may be advisable to adopt a restrictive approach to transfusions, as they can potentially have a negative effect on outcome.

Discovery of Generalizable TBI Phenotypes Using Multivariate Time-Series Clustering

Traumatic Brain Injury (TBI) presents a broad spectrum of clinical presentations and outcomes due to its inherent heterogeneity, leading to diverse recovery trajectories and varied therapeutic responses. While many studies have delved into TBI phenotyping for distinct patient populations, identifying TBI phenotypes that consistently generalize across various settings and populations remains a critical research gap. Our research addresses this by employing multivariate time-series clustering to unveil TBI's dynamic intricates. Utilizing a self-supervised learning-based approach to clustering multivariate time-Series data with missing values (SLAC-Time), we analyzed both the research-centric TRACK-TBI and the real-world MIMIC-IV datasets. Remarkably, the optimal hyperparameters of SLAC-Time and the ideal number of clusters remained consistent across these datasets, underscoring SLAC-Time's stability across heterogeneous datasets. Our analysis revealed three generalizable TBI phenotypes (α, β, and γ), each exhibiting distinct non-temporal features during emergency department visits, and temporal feature profiles throughout ICU stays. Specifically, phenotype α represents mild TBI with a remarkably consistent clinical presentation. In contrast, phenotype β signifies severe TBI with diverse clinical manifestations, and phenotype γ represents a moderate TBI profile in terms of severity and clinical diversity. Age is a significant determinant of TBI outcomes, with older cohorts recording higher mortality rates. Importantly, while certain features varied by age, the core characteristics of TBI manifestations tied to each phenotype remain consistent across diverse populations.

Mechanisms and treatment of anemia related to cardiac arrest

Cardiac arrest is a common and fatal emergency situation. Recently, an increasing number of studies have shown that anemia in patients with cardiac arrest is closely related to high mortality rates and poor neurological outcomes. Anemia is prevalent among patients with post-cardiac arrest syndrome (PCAS), but its specific pathogenesis remains unclear. The mechanisms may involve various factors, including reduced production of erythropoietin, oxidative stress/inflammatory responses, gastrointestinal ischemic injury, hepcidin abnormalities, iatrogenic blood loss, and malnutrition. Measures to improve anemia related to cardiac arrest may include blood transfusions, administration of erythropoietin, anti-inflammation and antioxidant therapies, supplementation of hematopoietic materials, protection of gastrointestinal mucosa, and use of hepcidin antibodies and antagonists. Therefore, exploring the latest research progress on the mechanisms and treatment of anemia related to cardiac arrest is of significant guiding importance for improving secondary brain injury caused by anemia and the prognosis of patients with cardiac arrest.

Effect of Peri-operative Blood Transfusion on Neurological Outcome Following Aneurysmal Subarachnoid Hemorrhage: A Prospective Observational Study

BACKGROUND

Anemia is a common complication of aneurysmal subarachnoid hemorrhage and is associated with unfavorable outcomes. Whether the physiological benefits of transfusion for anemia surpass the risk of blood transfusion remains to be determined.

OBJECTIVES

The primary outcome was to evaluate the impact of peri-operative blood transfusion on the long-term neurological outcome, assessed by Glasgow Outcome Scale Extended at 3 months. The secondary outcomes included the impact of transfusion on the short-term neurological outcome, assessed by Modified Rankin Score at discharge/7 days, and on the incidence of vasospasm, infarction, re-exploration, tracheostomy, and length of hospital stay.

MATERIAL AND METHODS

This prospective observational study was conducted on 185 patients with aneurysmal subarachnoid hemorrhage undergoing clipping of the aneurysmal neck. In our study, blood transfusion was administered to keep the target Hb around 10 g/dL.

RESULTS

Unfavorable long-term outcome was found in 27/97 (28%) of patients who received a blood transfusion as compared to 13/74 (18%) of patients who did not receive a transfusion (P = 0.116). Patients receiving transfusion had more chances of an unfavorable outcome at discharge/7 days as compared to those not transfused [44/103 (43%) versus 22/80 (27%)], P = 0.025. There were increased chances of vasospasm, infarction, re-exploration, tracheostomy, and increased length of hospital stay in patients receiving transfusion (P < 0.05).

CONCLUSIONS

The use of blood transfusion in patients with aneurysmal subarachnoid hemorrhage was associated with increased neurological complications and hence an unfavorable short-term outcome. However, when used judiciously as per the clinical requirements, blood transfusion did not have a significant effect on long-term neurological outcome.

Relative anemia and perioperative stroke in children with moyamoya

OBJECTIVES

Surgical revascularization for moyamoya arteriopathy decreases long-term stroke risk but carries a risk of perioperative ischemic complications. We aimed to evaluate modifiable stroke risk factors in children undergoing surgical revascularization for moyamoya.

MATERIALS AND METHODS

In this exploratory, single-center, retrospective cohort study, medical records of pediatric patients undergoing surgical revascularization for moyamoya arteriopathy at our center between 2003 and 2021 were reviewed. Candidate modifiable risk factors were analyzed for association with perioperative stroke, defined as ischemic stroke ≤7 days after surgery.

RESULTS

We analyzed 53 surgeries, consisting of 39 individual patients undergoing indirect surgical revascularization of 74 hemispheres. Perioperative ischemic stroke occurred following five surgeries (9.4%). There were no instances of hemorrhagic stroke. Larger pre-to-postoperative decreases in hemoglobin (OR 3.90, p=0.017), hematocrit (OR 1.69, p=0.012) and blood urea nitrogen (OR 1.83, p=0.010) were associated with increased risk of perioperative ischemic stroke. Weight-adjusted intraoperative blood loss was not associated with risk of perioperative ischemic stroke (OR 0.94, p=0.796). Among children with sickle cell disease, all of whom underwent exchange transfusion within one week prior to surgery, none experienced perioperative stroke.

CONCLUSIONS

Decreases in hemoglobin, hematocrit, and blood urea nitrogen between the preoperative and postoperative periods are associated with increased risk of perioperative stroke. These novel findings suggest that dilutional anemia, possibly due to standardly administered hyperhydration, may increase the risk of perioperative stroke in some children with moyamoya. Further work optimizing both mean arterial pressure and oxygen-carrying capacity in these patients, including consideration of alternative blood transfusion thresholds, is necessary.

Association of blood pressure parameters post mechanical thrombectomy in anemic versus non-anemic patients and clinical outcomes

INTRODUCTION

Higher blood pressure (BP) is considered to be detrimental in patients who undergo mechanical thrombectomy (MT), however, the impact of BP post-MT based on comorbidities like anemia has not been well studied. We aim to determine the association of 24-h post-MT BP parameters with clinical outcomes depending on their anemia status.

METHODS

We conducted a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 1/2015 to 12/2020. Patients were dichotomized into anemic and non-anemic groups based on the World Health Organization's definition of anemia [hemoglobin < 12.0 g/dL in women and < 13.0 g/dL in men]. We performed a multivariable analysis with binary logistic regression with the 24-h post-MT BP parameters as predictors. The outcomes were functional dependence (3-month mRS 3-6), mortality, and an early neurological improvement.

RESULTS

220 patients met the inclusion criteria. 158 (71.82 %) patients had functional dependence at 3-months. In the multivariable analysis, the parameters of a higher mean SBP (132.9 ± 11.94 vs.126.52 ± 13.3; OR, 1.05; 95 % CI, 1.02-1.09; P 0.011), a higher mean MAP (93.35 ± 8.44 vs.89.69 ± 10.03; OR,1.06; 95 % CI, 1.01-1.11; P 0.029) and a higher maximum MAP (115.26 ± 11.73 vs.109.37 ± 12.51; OR,1.05; 95 % CI, 1.01-1.08; P 0.023)were significantly associated with functional dependence in non-anemic patients, while a lower mean DBP (65.53 ± 9.73 vs. 71.94 ± 10.16; OR, 0.92; 95 % CI, 0.86-0.98; P 0.007), lower mean MAP (85.7 ± 8.65 vs. 91.38 ± 10; OR, 0.93; 95 % CI, 0.86-0.99; P 0.02), a lower minimum DBP (49.27 ± 10.51 vs. 55.1 ± 11.23; OR, 0.93; 95 % CI, 0.88-0.99; P 0.019), a lower minimum MAP (68.96 ± 9.54 vs. 74.73 ± 10.47; OR, 0.93; 95 % CI, 0.87-0.99; P 0.023) were significantly associated with mortality in patients with anemia, and a lower minimum DBP (54.75 ± 10.42 vs. 59.69 ± 8.87; OR, 0.95; 95 % CI, 0.91-0.99; P 0.012) and a lower minimum MAP (71.92 ± 14.7 vs.75.67 ± 14.17; OR, 0.97; 95 % CI, 0.94-0.99; P 0.047) were significantly associated with an early neurological improvement in non-anemic patients. For patients with anemia, there was no association between 24-hour BP Parameters post-MT and functional dependence and early neurological improvement, and between 24-hour BP Parameters post-MT and mortality in non-anemic patients.

CONCLUSION

In our study, higher BP parameters were associated with worse outcomes in patients without anemia, however, this effect was not found in patients with anemia. Certain lower BP parameters were associated with higher 3-month mortality in anemic patients; however, this effect was not found in non-anemic patients. Higher BP post-MT can potentially promote perfusion and thus is not associated with worse outcomes in anemic patients post-MT, whereas in non-anemic patients it may potentially lead to reperfusion injury While our study is limited because of size and its retrospective nature, the findings suggest that an individualized approach to tailor the target BP post-MT to a patient's risk factor profile and associated co-morbid conditions to achieve optimization of medical care post-MT and associated co-morbid conditions to achieve optimization of medical care post-MT.

A reassessment of hemoglobin and hematoma expansion in intracerebral hemorrhage

BACKGROUND

In patients with spontaneous intracerebral hemorrhage (ICH), prior studies identified an increased risk of hematoma expansion (HE) in those with lower admission hemoglobin (Hgb) levels. We aimed to reproduce these findings in an independent cohort.

METHODS

We conducted a cohort study of patients admitted to a Comprehensive Stroke Center for acute ICH within 24 hours of onset. Admission laboratory and CT imaging data on ICH characteristics including HE (defined as >33% or >6 mL), and 3-month outcomes were collected. We compared laboratory data between patients with and without HE and used multivariable logistic regression to determine associations between Hgb, HE, and unfavorable 3-month outcomes (modified Rankin Scale 4-6) while adjusting for confounders including anticoagulant use, and laboratory markers of coagulopathy.

RESULTS

Among 345 patients in our cohort (mean [SD] age 72.9 [13.7], 49% male), 71 (21%) had HE. Patients with HE had similar Hgb versus those without HE (mean [SD] 13.1 [1.8] g/dl vs. 13.1 [1.9] g/dl, p=0.92). In fully adjusted multivariable models, Hgb was not associated with HE (OR per 1g/dl 1.01, 95% CI 0.86 -1.17, p = 0.94), however higher admission Hgb levels were associated with lower odds of unfavorable 3-month outcome (OR 0.83 per 1 g/dl Hgb, 95% CI 0.72-0.96, p=0.01).

CONCLUSION

We did not confirm a previously reported association between admission Hgb and HE in patients with ICH, although Hgb and HE were both associated with poor outcome. These findings suggest that the association between Hgb and poor outcome is mediated by other factors.

Brain-Lung Crosstalk: Management of Concomitant Severe Acute Brain Injury and Acute Respiratory Distress Syndrome

Purpose of Review

To summarize pathophysiology, key conflicts, and therapeutic approaches in managing concomitant severe acute brain injury (SABI) and acute respiratory distress syndrome (ARDS).

Recent Findings

ARDS is common in SABI and independently associated with worse outcomes in all SABI subtypes. Most landmark ARDS trials excluded patients with SABI, and evidence to guide decisions is limited in this population. Potential areas of conflict in the management of patients with both SABI and ARDS are (1) risk of intracranial pressure (ICP) elevation with high levels of positive end-expiratory pressure (PEEP), permissive hypercapnia due to lung protective ventilation (LPV), or prone ventilation; (2) balancing a conservative fluid management strategy with ensuring adequate cerebral perfusion, particularly in patients with symptomatic vasospasm or impaired cerebrovascular blood flow; and (3) uncertainty about the benefit and harm of corticosteroids in this population, with a mortality benefit in ARDS, increased mortality shown in TBI, and conflicting data in other SABI subtypes. Also, the widely adapted partial pressure of oxygen (PaO2) target of > 55 mmHg for ARDS may exacerbate secondary brain injury, and recent guidelines recommend higher goals of 80-120 mmHg in SABI. Distinct pathophysiology and trajectories among different SABI subtypes need to be considered.

Summary

The management of SABI with ARDS is highly complex, and conventional ARDS management strategies may result in increased ICP and decreased cerebral perfusion. A crucial aspect of concurrent management is to recognize the risk of secondary brain injury in the individual patient, monitor with vigilance, and adjust management during critical time windows. The care of these patients requires meticulous attention to oxygenation and ventilation, hemodynamics, temperature management, and the neurological exam. LPV and prone ventilation should be utilized, and supplemented with invasive ICP monitoring if there is concern for cerebral edema and increased ICP. PEEP titration should be deliberate, involving measures of hemodynamic, pulmonary, and brain physiology. Serial volume status assessments should be performed in SABI and ARDS, and fluid management should be individualized based on measures of brain perfusion, the neurological exam, and cardiopulmonary status. More research is needed to define risks and benefits in corticosteroids in this population.

Interplay between anemia parameters and collateral status in patients who undergo mechanical thrombectomy

INTRODUCTION

Anemia is associated with higher morbidity and mortality, but its association with acute ischemic stroke (AIS) is not well established. We aim to determine the association of five-day anemia parameters with clinical outcomes in patients with an AIS, depending on their pre-mechanical thrombectomy (MT) collateral status.

METHODS

We performed a retrospective chart review of patients who underwent MT at a comprehensive stroke center from 7/2014 to 12/2020. The patients were divided into good and poor collateral groups depending on their pre-MT collateral status. A blinded board-certified neuroradiologist used collateral grading scale of Maas ≥ 3 to designate good collaterals on the pre-MT CT Angiogram. A binary logistic regression analysis was performed, controlling for the baseline parameters, with the five-day anemia parameters as predictors. The outcomes were functional independence (mRS 0-2), mortality, and early neurological improvement.

RESULTS

A total of 220 met the inclusion criteria. 94 (42.72 %) patients had good collaterals, while 126 (57.27 %) patients had poor collaterals. In the multivariable analysis, for patients with good collaterals, the higher values of five-day mean Hb (12.41 ± 1.87 vs 11.32 ± 1.95; OR, 0.72; 95 % CI, 0.54-0.95; P 0.018), five-day mean HCT (37.43 ± 5.1 vs 34.35 ± 5.5; OR, 0.89; 95 % CI, 0.81-0.98; P 0.018) and lower values of the difference between peak and trough values of Hb (1.75 ± 1.15 vs 2.41 ± 1.35; OR, 1.71; 95 % CI, 1.07-2.74; P 0.025) were associated with functional independence. For patients with poor collaterals, there was no association between five-day mean Hb, mean HCT parameters with functional independence, lower mortality, and early neurological improvement.

CONCLUSION

Our study was suggestive of an association between higher mean values of Hb and HCT over a five-day period and good clinical outcomes in patients with good collaterals who undergo MT for an anterior circulation LVO. This association was not found in the poor collateral group.

Incidence and Associated Factors of Anemia in Patients with Acute Moderate and Severe Traumatic Brain Injury

Background

Anemia might contribute to the development of secondary injury in patients with acute traumatic brain injury (TBI). Potential determinants of anemia are still poorly acknowledged, and reported incidence of declined hemoglobin concentration varies widely between different studies. The aim of this study was to investigate the incidence of severe anemia among patients with moderate to severe TBI and to evaluate patient- and trauma-related factors that might be associated with the development of anemia.

Methods

This retrospective cohort study involved all adult patients admitted to Tampere University Hospital’s emergency department for moderate to severe TBI (August 2010 to July 2012). Detailed information on patient demographics and trauma characteristics were obtained, including data on posttraumatic care, data on neurosurgical procedures, and all measured in-hospital hemoglobin values. Severe anemia was defined as a hemoglobin level less than 100 g/L. Both univariate and multivariable analyses were performed, and hemoglobin trajectories were created.

Results

The study included 145 patients with moderate to severe TBI (male 83.4%, mean age 55.0 years). Severe anemia, with a hemoglobin level less than 100 g/L, was detected in 66 patients (45.5%) and developed during the first 48 h after the trauma. In the univariate analysis, anemia was more common among women (odds ratio [OR] 2.84; 95% confidence interval [CI] 1.13–7.15), patients with antithrombotic medication prior to trauma (OR 3.33; 95% CI 1.34–8.27), patients with cardiovascular comorbidities (OR 3.12; 95% CI 1.56–6.25), patients with diabetes (OR 4.56; 95% CI 1.69–12.32), patients with extracranial injuries (OR 3.14; 95% CI 1.69–12.32), and patients with midline shift on primary head computed tomography (OR 2.03; 95% CI 1.03–4.01). In the multivariable analysis, midline shift and extracranial traumas were associated with the development of severe anemia (OR 2.26 [95% CI 1.05–4.48] and OR 4.71 [95% CI 1.74–12.73], respectively).

Conclusions

Severe anemia is common after acute moderate to severe TBI, developing during the first 48 h after the trauma. Possible anemia-associated factors include extracranial traumas and midline shift on initial head computed tomography.

Association of anemia with functional outcomes in patients with mechanical thrombectomy

INTRODUCTION

Anemia at presentation is associated with worse outcomes in patients with acute ischemic stroke (AIS). We aim to investigate the association of anemia parameters with functional dependence and mortality in patients who undergo mechanical thrombectomy (MT).

METHODS

We performed a retrospective chart review of patients who underwent MT for an anterior circulation large vessel occlusion at a comprehensive stroke center from 1/2015-6/2020. Anemia was considered as a dichotomous categorical variable with a cutoff point of hemoglobin (Hb) < 12.0 g/dL in women and < 13.0 g/dL in men, as per the definition of the World Health Organization. Mean values of Hb and hematocrit (HCT) were obtained over the first five days of admission. Hemoglobin and HCT variability were measured using standard deviation (SD), and coefficient variability (CV) over the first five days of admission. Values of variance and difference (the difference between peak and trough of Hemoglobin or HCT) were also recorded. Multivariate logistic regression analyses were performed, including the predictor variables which were contributing significantly to the model (P < 0.05) in the univariate analysis, with 30-day functional dependence (mRS 3-6) (primary outcome) and 30-day mortality (secondary outcome) as the dependent variables.

RESULTS

188 patients met our inclusion criteria. Anemia on presentation, lower mean and minimum values of five-day Hb and HCT, and higher variability in five-day Hb and HCT parameters were associated with higher 3-month mortality. Men with lower mean and minimum values of five-day Hb and HCT had a significantly higher likelihood of functional dependence at 3-months. This finding was not replicated amongst women in our cohort.

CONCLUSION

Our study demonstrated higher 3-mortality in patients with anemia and Hb variability. Our study also demonstrated a higher likelihood of functional dependence in patients amongst men with anemia.

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.

Admission Hemoglobin Levels Are Associated With Functional Outcome in Spontaneous Intracerebral Hemorrhage

OBJECTIVES

To test the hypothesis that admission hemoglobin levels are associated with outcome in primary, nontraumatic intracerebral hemorrhage.

DESIGN

Individual patient data meta-analysis of three studies of intracerebral hemorrhage.

SETTING

Two randomized clinical trials and one multiethnic observational study.

PATIENTS

Patients with spontaneous, nontraumatic intracerebral hemorrhage.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Our exposure of interest was admission hemoglobin levels and the primary outcome was 3-month postintracerebral hemorrhage-dichotomized modified Rankin Scale (0-3 vs 4-6). Intermediate outcomes were admission hematoma volume and hematoma expansion defined as 6 mL or 33% increase in hemorrhage size on repeat CT. A total of 4,172 intracerebral hemorrhage patients were included in the study (mean age 63 [sd = 14]; female sex 1,668 [40%]). Each additional g/dL of admission hemoglobin was associated with 14% (odds ratio, 0.86; 95% CI, 0.82-0.91) and 7% (odds ratio, 0.93; 95% CI, 0.88-0.98) reductions in the risk of poor outcome in unadjusted and adjusted analyses, respectively. Dose-response analyses indicated a linear relationship between admission hemoglobin levels and poor outcome across the entire evaluated range (test-for-trend p < 0.001). No consistent associations were found between the admission hemoglobin levels and hematoma volume or hematoma expansion.

CONCLUSIONS

Higher hemoglobin levels are associated with better outcome in intracerebral hemorrhage. Further research is needed to evaluate admission hemoglobin levels as both a therapeutic target and predictor of outcome.

South African Society of Anaesthesiologists Perioperative Patient Blood Management Guidelines 2020

Anaesthesiologists regularly request and administer blood components to their patients, a potentially life-saving intervention. All anaesthesiologists must be familiar with the indications and appropriate use of blood and blood components and their alternatives, but close liaison with haematologists and their local haematology blood sciences laboratory is encouraged. In the last decade, there have been considerable changes in approaches to optimal use of blood components, together with the use of alternative products, with a need to update previous guidelines and adapt them for anaesthesiologists working throughout the hospital system.

Effect of Red Blood Cell Storage Duration on Outcomes of Isolated Traumatic Brain Injury

Background

The aim of this study was to investigate the effects of red blood cell (RBC) storage duration on the outcomes of adult isolated traumatic brain injury (iTBI) patients after transfusion.

Material/Methods

A total of 1252 adult iTBI patients who received the fresh RBCs (stored for ≤14 days) or old RBCs (stored for >14 days) were finally enrolled in this study. The primary outcome was 90-day mortality. The secondary outcomes were in-hospital mortality, nosocomial infection, and complications.

Results

By 90 days after RBC transfusion, 89 patients (17.0%) had died in the fresh RBC group, and 107 had died (14.7%) in the old RBC group, with no significant difference in 90-day mortality between the 2 groups (OR=1.192, 95% CI: 0.877–1.620, P=0.261). According to ISS score, no differences were discovered in mild injury (OR=1.079, 95% CI: 0.682–1.707, P=0.746), severe injury (OR=1.055, 95% CI: 0.634–1.755, P=0.838), and more severe injury (OR=1.940, 95% CI: 0.955–3.943, P=0.064). For GCS score, there were no differences in mild injury (OR=1.546, 95% CI: 0.893–2.676, P=0.118), moderate injury (OR=0.965, 95% CI: 0.616–1.513, P=0.877), and severe injury (OR=1.332, 95% CI: 0.677–2.620, P=0.406). We also observed no significant differences in secondary outcomes.

Conclusions

Use of old RBCs did not increase the 90-day mortality in adult iTBI patients.

Unannotated single nucleotide polymorphisms in the TATA box of erythropoiesis genes show in vitro positive involvements in cognitive and mental disorders

BACKGROUND

Hemoglobin is a tetramer consisting of two α-chains and two β-chains of globin. Hereditary aberrations in the synthesis of one of the globin chains are at the root of thalassemia, one of the most prevalent monogenic diseases worldwide. In humans, in addition to α- and β-globins, embryonic zeta-globin and fetal γ-globin are expressed. Immediately after birth, the expression of fetal Aγ- and Gγ-globin ceases, and then adult β-globin is mostly expressed. It has been shown that in addition to erythroid cells, hemoglobin is widely expressed in nonerythroid cells including neurons of the cortex, hippocampus, and cerebellum in rodents; embryonic and adult brain neurons in mice; and mesencephalic dopaminergic brain cells in humans, mice, and rats. Lately, there is growing evidence that different forms of anemia (changes in the number and quality of blood cells) may be involved in (or may accompany) the pathogenesis of various cognitive and mental disorders, such as Alzheimer's and Parkinson's diseases, depression of various severity levels, bipolar disorders, and schizophrenia. Higher hemoglobin concentrations in the blood may lead to hyperviscosity, hypovolemia, and lung diseases, which may cause brain hypoxia and anomalies of brain function, which may also result in cognitive deficits.

METHODS

In this study, a search for unannotated single-nucleotide polymorphisms (SNPs) of erythroid genes was initially performed using our previously created and published SNP-TATA_Z-tester, which is a Web service for computational analysis of a given SNP for in silico estimation of its influence on the affinity of TATA-binding protein (TBP) for TATA and TATA-like sequences. The obtained predictions were finally verified in vitro by an electrophoretic mobility shift assay (EMSA).

RESULTS

On the basis of these experimental in vitro results and literature data, we studied TATA box SNPs influencing both human erythropoiesis and cognitive abilities. For instance, TBP-TATA affinity in the HbZ promoter decreases 6.6-fold as a result of a substitution in the TATA box (rs113180943), thereby possibly disrupting stage-dependent events of "switching" of hemoglobin genes and thus causing erythroblastosis. Therefore, rs113180943 may be a candidate marker of severe hemoglobinopathies with comorbid cognitive and mental disorders associated with cerebral blood flow disturbances.

CONCLUSIONS

The literature data and experimental and computations results suggest that the uncovered candidate SNP markers of erythropoiesis anomalies may also be studied in cohorts of patients with cognitive and/or mental disorders with comorbid erythropoiesis diseases in comparison to conventionally healthy volunteers. Research into the regulatory mechanisms by which the identified SNP markers contribute to the development of hemoglobinopathies and of the associated cognitive deficits will allow physicians not only to take timely and adequate measures against hemoglobinopathies but also to implement strategies preventing cognitive and mental disorders.

Critical Care Society of Southern Africa adult patient blood management guidelines: 2019 Round-table meeting, CCSSA Congress, Durban, 2018

The CCSSA PBM Guidelines have been developed to improve patient blood management in critically ill patients in southern Africa. These consensus recommendations are based on a rigorous process by experts in the field of critical care who are also practicing in South Africa (SA). The process comprised a Delphi process, a round-table meeting (at the CCSSA National Congress, Durban, 2018), and a review of the best available evidence and international guidelines. The guidelines focus on the broader principles of patient blood management and incorporate transfusion medicine (transfusion guidelines), management of anaemia, optimisation of coagulopathy, and administrative and ethical considerations. There are a mix of low-middle and high-income healthcare structures within southern Africa. Blood products are, however, provided by the same not-for-profit non-governmental organisations to both private and public sectors. There are several challenges related to patient blood management in SA due most notably to a high incidence of anaemia, a frequent shortage of blood products, a small donor population, and a healthcare system under financial strain. The rational and equitable use of blood products is important to ensure best care for as many critically ill patients as possible. The summary of the recommendations provides key practice points for the day-to-day management of critically ill patients. A more detailed description of the evidence used to make these recommendations follows in the full clinical guidelines section.

Evaluation of blood product transfusion therapies in acute injury care in low- and middle-income countries: a systematic review

BACKGROUND

Worldwide, injuries account for approximately five million mortalities annually, with 90% occurring in low- and middle-income countries (LMICs). Although guidelines characterizing data for blood product transfusion in injury resuscitation have been established for high-income countries (HICs), no such information on use of blood products in LMICs exists. This systematic review evaluated the available literature on the use and associated outcomes of blood product transfusion therapies in LMICs for acute care of patients with injuries.

METHODS

A systematic search of PubMed, EMBASE, Global Health, CINAHL and Cochrane databases through November 2018 was performed by a health sciences medical librarian. Prospective and cross-sectional reports of injured patients from LMICs involving data on blood product transfusion therapies were included. Two reviewers identified eligible records (κ=0.92); quality was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. Report elements, patient characteristics, injury information, blood transfusion therapies provided and mortality outcomes were extracted and analyzed.

RESULTS

Of 3411 records, 150 full-text reports were reviewed and 17 met inclusion criteria. Identified reports came from the World Health Organization regions of Africa, the Eastern Mediterranean, and South-East Asia. A total of 6535 patients were studied, with the majority from exclusively inpatient hospital settings (52.9%). Data on transfusion therapies demonstrated that packed red blood cells were given to 27.0% of patients, fresh frozen plasma to 13.8%, and unspecified product types to 50.1%. Among patients with blunt and penetrating injuries, 5.8% and 15.7% were treated with blood product transfusions, respectively. Four reports provided data on comparative mortality outcomes, of which two found higher mortality in blood transfusion-treated patients than in untreated patients at 17.4% and 30.4%. The overall quality of evidence was either low (52.9%) or very low (41.2%), with one report of moderate quality by GRADE criteria.

CONCLUSION

There is a paucity of high-quality data to inform appropriate use of blood transfusion therapies in LMIC injury care. Studies were geographically limited and did not include sufficient data on types of therapies and specific injury patterns treated. Future research in more diverse LMIC settings with improved data collection methods is needed to inform injury care globally.

RBC Transfusion Strategies in the ICU: A Concise Review

OBJECTIVES

To critically assess available high-level clinical studies regarding RBC transfusion strategies, with a focus on hemoglobin transfusion thresholds in the ICU.

DATA SOURCES

Source data were obtained from a PubMed literature review.

STUDY SELECTION

English language studies addressing RBC transfusions in the ICU with a focus on the most recent relevant studies.

DATA EXTRACTION

Relevant studies were reviewed and the following aspects of each study were identified, abstracted, and analyzed: study design, methods, results, and implications for critical care practice.

DATA SYNTHESIS

Approximately 30-50% of ICU patients receive a transfusion during their hospitalization with anemia being the indication for 75% of transfusions. A significant body of clinical research evidence supports using a restrictive transfusion strategy (e.g., hemoglobin threshold < 7 g/dL) compared with a more liberal approach (e.g., hemoglobin threshold < 10 g/dL). A restrictive strategy (hemoglobin < 7 g/dL) is recommended in patients with sepsis and gastrointestinal bleeds. A slightly higher restrictive threshold is recommended in cardiac surgery (hemoglobin < 7.5 g/dL) and stable cardiovascular disease (hemoglobin < 8 g/dL). Although restrictive strategies are generally supported in hematologic malignancies, acute neurologic injury, and burns, more definitive studies are needed, including acute coronary syndrome. Massive transfusion protocols are the mainstay of treatment for hemorrhagic shock; however, the exact RBC to fresh frozen plasma ratio is still unclear. There are also emerging complimentary practices including nontransfusion strategies to avoid and treat anemia and the reemergence of whole blood transfusion.

CONCLUSIONS

The current literature supports the use of restrictive transfusion strategies in the majority of critically ill populations. Continued studies of optimal transfusion strategies in various patient populations, coupled with the integration of novel complementary ICU practices, will continue to enhance our ability to treat critically ill patients.

Clinical Significance of Nadir Hemoglobin in Predicting Neurologic Outcome in Infants With Abused Head Trauma

Traumatic brain injury (TBI) is a leading cause of pediatric morbidity and mortality and is categorized as abusive head trauma (AHT) and accidental head injury. A retrospective chart review of 124 children aged <1 year diagnosed with TBI were analyzed. Outcomes were evaluated at discharge and 6 months later by using the Pediatric Cerebral Performance Category (PCPC) Scale. The receiver operating characteristic (ROC) curve was applied to determine the cutoff values for hemoglobin (HB) levels. In the study, 50 infants (40.3%) achieved a favorable neurologic outcome (PCPC ≦ 2) and 74 (59.7%) had poor neurologic outcomes (PCPC ≧ 3). Infants with poor neurologic outcomes had lower HB on admission and nadir HB (p < 0.05). Based on multivariate logistic regression analysis, the nadir HB was a predictor of poor neurologic outcomes at discharge and 6 months later in both AHT and accidental head injury. Nadir HB had the largest area under the ROC curve for predicting poor neurologic outcomes. We determined the appropriate cutoff value of nadir HB as 9.35 g/dl for predicting neurologic outcomes in infants with TBI. Furthermore, the cutoff value of nadir HB in predicting poor neurologic outcomes in infants caused by AHT and accidental head injury were taken as 9.36 and 8.75 g/dl, respectively.

Association of hemoglobin with incidence of in-hospital cardiac arrest in patients with acute coronary syndrome complicated by cardiogenic shock

Objective

This study was performed to investigate the association of the admission hemoglobin level with the incidence of in-hospital cardiac arrest (IHCA) in patients with acute coronary syndrome (ACS) complicated by cardiogenic shock (CS).

Methods

In this retrospective study, we reviewed the medical records of consecutive patients with ACS complicated by CS admitted to the coronary care unit from January 2014 to October 2017. Logistic regression models were carried out to evaluate the association between hemoglobin and the incidence of IHCA. Interaction and subgroup analyses were also performed.

Results

In total, 211 patients were included in the study, and 61 (28.9%) patients developed IHCA. In the multivariable analysis, hemoglobin was a strong independent predictor of IHCA (odds ratio, 0.971; 95% confidence interval, 0.954–0.989). In the fully adjusted model, patients in the higher hemoglobin tertile were less likely to develop IHCA than patients in the lowest hemoglobin tertile (odds ratio, 0.194; 95% confidence interval, 0.071–0.530). The relationship remained stable in most subgroups except patients aged ≥70 years.

Conclusion

In patients with ACS complicated by CS, the incidence of IHCA is related to the hemoglobin concentration, and a high hemoglobin concentration is a protective factor against the development of IHCA.

[Neuroprotection in neurocritical care]

In intensive care medicine neuroprotection is understood mostly as various measures to avoid secondary brain damage after initial trauma, as in stroke, intracranial hemorrhage and resuscitation. Every brain trauma differs in the damage pattern and dynamics depending on the primary form of injury. Therefore, there are targeted treatment approaches depending on the pathophysiology of the medical condition. In addition, neuroprotective methods are desirable that are effective in the majority of patients with acute brain injury. In actual fact, in all forms of acute brain injury certain pathophysiological courses are encountered, which can lead to secondary brain damage depending on the intensity, e.g. reperfusion injury, damage to the blood-brain barrier and excitotoxicity. There is evidence to suggest that the creation of physiologically normal conditions leads to a favorable situation for the damaged brain. This article firstly describes the relevance of neuroprotective measures in neurocritical care medicine. Subsequently, general pathophysiological mechanisms in brain trauma are described. Following this, the pathophysiology and treatment options in brain pressure crises (reduction of intracranial pressure), anemia (transfusion management), hyperglycemia and hypoglycemia (adjustment of the blood sugar level) are dealt with. Finally, the use and benefits of therapeutic hypothermia are discussed. This has a special position as the only clinically effective individual measure for neuroprotection. The focus here is on the application following circulatory and cardiac arrest and resuscitation.

Current state of transfusion in traumatic brain injury and associated coagulopathy

Traumatic brain injury (TBI)-induced coagulopathy has long been recognized as a significant risk for poor outcomes in patients with TBI, but its pathogenesis remains poorly understood. As a result, current treatment options for the condition are limited and ineffective. The lack of information is most significant for the impact of blood transfusions on patients with isolated TBI and in the absence of confounding influences from trauma to the body and limbs and the resultant hemorrhagic shock. Here we discuss recent progress in understanding the pathogenesis of TBI-induced coagulopathy and the current state of blood transfusions for patients with TBI and associated coagulopathy.

A murine neonatal model of necrotizing enterocolitis caused by anemia and red blood cell transfusions

Necrotizing enterocolitis (NEC) is an idiopathic, inflammatory bowel necrosis of premature infants. Clinical studies have linked NEC with antecedent red blood cell (RBC) transfusions, but the underlying mechanisms are unclear. Here we report a neonatal murine model to investigate this association. C57BL/6 mouse pups rendered anemic by timed phlebotomy and then given RBC transfusions develop NEC-like intestinal injury with prominent necrosis, inflammation, and submucosal edema/separation of the lamina propria in the ileocecal region and colon within 12-24 h. The anemic intestine is infiltrated by inflammatory macrophages, which are activated in situ by RBC transfusions via a Toll-like receptor (TLR)-4-mediated mechanism and cause bowel injury. Chelation of RBC degradation products with haptoglobin, absence of TLR4, macrophage depletion, and inhibition of macrophage activation is protective. Intestinal injury worsens with increasing severity and the duration of anemia prior to transfusion, indicating a need for the re-evaluation of current transfusion guidelines for premature infants.

Associations of Anemia With Outcomes in Patients With Spontaneous Intracerebral Hemorrhage: A Meta-Analysis

Background: Intracerebral hemorrhage (ICH) is a highly lethal disease without effective therapeutic interventions. Anemia is prevalent in neurocritical disease and correlated with higher mortality in the intensive care unit. However, there is a lack of evidence concerning the association between anemia and the clinical outcomes of ICH.

Object: We aimed to assess the association between anemia and outcomes in patients with ICH.

Methods: We systematically searched the Cochrane Library, MEDLINE, EMBASE and Web of Science from inception to November 2017. Eligible studies were cohort studies exploring the association between anemia and mortality or functional outcomes in patient with ICH. A Meta-analysis was performed, and heterogeneity was assessed using the I² index. Sensitivity analyses were performed to account for heterogeneity and risk of bias. Effect estimates were combined using random effects model for mortality and poor outcomes.

Results: We identified seven cohort studies with 7,328 ICH patients, including 1,546 patients with anemia. The meta-analysis revealed that anemia was associated with higher mortality {OR = 1.72 for 30-day mortality (95% CI 1.37 to 2.15; I² = 64%; low-quality evidence); OR = 2.05 for 12-month mortality (95% CI 1.42 to 2.97; I² = 82%; low-quality evidence)} and an increased risk of poor outcome in patients with ICH {OR = 2.29 for 3-month outcome (95% CI 1.16 to 4.51; I² = 91%; very low-quality evidence); OR = 3.42 for 12-month outcome (95% CI 0.50 to 23.23; I² = 96%; very low-quality evidence)}.

Conclusions: Anemia on admission was associated with higher mortality and an increased risk of poor outcome in patients with ICH. However, the results were limited by the high heterogeneity of included studies. Prospective, multi-center or population-based, large sample cohort studies are needed in the future.

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

PURPOSE

Optimal red blood cell (RBC) transfusion thresholds in acute brain injury (ABI) are poorly defined.

MATERIALS AND METHODS

We conducted a retrospective cohort study of adult patients with ABI and moderate anemia (Hb 7-10 g/dL) in a neurological intensive care unit (ICU) at an academic medical center between 2008 and 2015. Transfused and non-transfused patients were matched based on age, ABI subtype, pre-transfusion hemoglobin, and ICU length of stay (LOS) at the time of RBC transfusion. Multivariable regression analyses were performed to assess the relationship between RBC transfusion and hospital LOS, hospital mortality, ICU LOS, ICU mortality, and 24 h change in sequential organ failure assessment (SOFA) scores.

RESULTS

2638 patients met inclusion criteria, with 225 (8.5%) receiving RBC transfusion. Acute ischemic stroke was the most prevalent ABI diagnosis (43.3%) then intracranial hemorrhage (25.6%), subarachnoid hemorrhage (16.5%), and traumatic brain injury (TBI) (14.6%). In multivariable analyses, RBC transfusion was associated with longer hospital and ICU LOS, and higher SOFA scores. Each ABI subtype had similar results, except for TBI which showed no difference in hospital LOS. Mortality was not significantly different.

CONCLUSIONS

In moderately anemic patients with ABI, RBC transfusion was associated with longer hospital and ICU LOS. Prospective investigations are necessary to further assess these relationships.

Transfusion practices in traumatic brain injury

Purpose of review

The aim of this review is to summarize the recent studies looking at the effects of anemia and red blood cell transfusion in critically-ill patients with traumatic brain injury (TBI), describe the transfusion practice variations observed worldwide, and outline the ongoing trials evaluating restrictive versus liberal transfusion strategies for TBI.

Recent findings

Anemia is common among critically-ill patients with TBI, it is also thought to exacerbate secondary brain injury, and is associated with an increased risk of poor outcome. Conversely, allogenic red blood cell transfusion carries its own risks and complications, and has been associated with worse outcomes. Globally, there are large reported differences in the hemoglobin threshold used for transfusion after TBI. Observational studies have shown differential results for improvements in cerebral oxygenation and metabolism after red blood cell transfusion in TBI.

Summary

Currently, there is insufficient evidence to make strong recommendations regarding which hemoglobin threshold to use as a transfusion trigger in critically-ill patients with TBI. There is also uncertainty whether the restrictive transfusion strategy used in general critical care can be extrapolated to acutely brain injured patients. Ultimately, the consequences of anemia-induced cerebral injury need to be weighed up against the risks and complications associated with red blood cell transfusion.

Altered white matter microstructure mediates the relationship between hemoglobin levels and cognitive control deficits in end-stage renal disease patients

The brain-kidney crosstalk theory suggested that the brain and kidneys may be considered end organs on parallel trajectories and subject to shared risk factors, which are receiving increasing attention. Cognitive control deficits were frequently presented in patients with end-stage renal disease (ESRD). Whether or not cognitive control impairment is concerned with brain-kidney crosstalk is in need of further research. To detect the relationship between ESRD and cognitive control impairment, diffusion tensor imaging was collected in 64 healthy controls (HCs) and 64 patients with ESRD. Tract-based spatial statistics and fixel-based analysis were used to detect the difference of white matter (WM) microstructure and morphology between ESRD patients and HCs in the whole brain. Tractography atlas-based analysis was also used to investigate the difference of diffusional characteristics along fiber bundles of interest between the two groups. For the whole-brain analysis, ESRD patients showed WM microstructural alteration and fiber density variation in the cingulum. In addition, ESRD patients exhibited higher MD and RD than HCs along the anterior cingulum. Among all of the blood biochemistry tests that represent kidney disease to a degree, the stepwise regression analysis showed that only hemoglobin significantly contributed to the cognitive control deficits in ESRD patients. Mediation analysis proved that the relationship between hemoglobin and cognitive control deficits of ESRD patients was mediated by WM microstructural alteration of the cingulum. Our results indicated that the anterior cingulum was correlated with cognitive control deficits and mediated the impact of hemoglobin on cognitive control.

Association of Anemia with Stroke Severity in Acute Ischemic Stroke Patients

Objective: To investigate the association of anemia with stroke severity in acute ischemic stroke patients.

Material & methods: We enrolled 96 patients (mean age: 60.25 ± 11.92 years old) who were admitted to the stroke unit of Shifa International Hospital between 1st March 2015 and 31st August 2015. Each patient presented within 72 hours of onset of symptoms, underwent computed tomography (CT) of the head and blood tests, including hemoglobin concentration, on the first day of hospitalization. Stroke severity was assessed on admission using the National Institute of Health Stroke Scale. Anemia was evaluated according to the World Health Organization (WHO) criteria (men, <13 g/dL; women, <12 g/dL). We examined the frequency of anemia in patients with different severities of acute ischemic stroke.

Results: World Health Organization defined anemia was positive in 38 (39.6%) and negative in 58 (60.4%) patients. Among the patients who were positive for anemia, seven (18.4%) had a minor stroke, 10 (26.3%) had a moderately severe stroke, and 21 (55.3%) had a severe stroke. There was a significant association between anemia and stroke severity (P-value 0.000).

Conclusion: Our data indicated that anemia was a frequent finding in acute ischemic stroke patients, with increasing frequency corresponding to stroke severity.

Anaemia and red blood cell transfusion in intracranial neurosurgery: a comprehensive review

Both anaemia and blood transfusion are associated with poor outcomes in the neurosurgical population. Based on the available literature, the optimal haemoglobin concentration for neurologically injured patients appears to be in the range of 9.0-10.0 g dl^-1, although the individual risks and benefits should be weighed. Several perioperative blood conservation strategies have been used successfully in neurosurgery, including correction of anaemia and coagulopathy, use of antifibrinolytics, and intraoperative cell salvage. Avoidance of non-steroidal anti-inflammatory drugs and starch-containing solutions is recommended given the potential for platelet dysfunction.

Hemoglobin thresholds and red blood cell transfusion in adult patients with moderate or severe traumatic brain injuries: A retrospective cohort study

PURPOSE

We aimed to evaluate the association between transfusion practices and clinical outcomes in patients with traumatic brain injury.

MATERIAL AND METHODS

We conducted a retrospective cohort study of adult patients with moderate or severe traumatic brain injury admitted to the intensive care unit (ICU) of a level I trauma center between 2009 and 2013. The associations between hemoglobin (Hb) level, red blood cell (RBC) transfusion and clinical outcomes were estimated using robust Poisson models and proportional hazard models with time-dependent variables, adjusted for confounders.

RESULTS

We included 215 patients. Sixty-six patients (30.7%) were transfused during ICU stay. The median pre-transfusion Hb among transfused patients was 81g/L (IQR 67-100), while median nadir Hb among non-transfused patients was 110g/L (IQR 93-123). Poor outcomes were significantly more frequent in patients who were transfused (mortality risk ratio [RR]: 2.15 [95% CI 1.37-3.38] and hazard ratio: 3.06 [95% CI 1.57-5.97]; neurological complications RR: 3.40 [95% CI 1.35-8.56]; trauma complications RR: 1.65 [95% CI 1.31-2.08]; ICU length of stay geometric mean ratio: 1.42 [95% CI 1.06-1.92]).

CONCLUSIONS

During ICU stay, transfused patients tended to have lower Hb levels and worse outcomes than patients who did not receive RBCs, after adjustment for confounders.

Acute respiratory distress syndrome in traumatic brain injury: how do we manage it?

Traumatic brain injury (TBI) is an important cause of morbidity and mortality worldwide. TBI patients frequently suffer from lung complications and acute respiratory distress syndrome (ARDS), which is associated with poor clinical outcomes. Moreover, the association between TBI and ARDS in trauma patients is well recognized. Mechanical ventilation of patients with a concomitance of acute brain injury and lung injury can present significant challenges. Frequently, guidelines recommending management strategies for patients with traumatic brain injuries come into conflict with what is now considered best ventilator practice. In this review, we will explore the strategies of the best practice in the ventilatory management of patients with ARDS and TBI, concentrating on those areas in which a conflict exists. We will discuss the use of ventilator strategies such as protective ventilation, high positive end expiratory pressure (PEEP), prone position, recruitment maneuvers (RMs), as well as techniques which at present are used for 'rescue' in ARDS (including extracorporeal membrane oxygenation) in patients with TBI. Furthermore, general principles of fluid, haemodynamic and hemoglobin management will be discussed. Currently, there are inadequate data addressing the safety or efficacy of ventilator strategies used in ARDS in adult patients with TBI. At present, choice of ventilator rescue strategies is best decided on a case-by-case basis in conjunction with local expertise.

The Effects of Red Blood Cell Transfusion on Functional Outcome after Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The optimal red blood cell transfusion (RBCT) trigger for patients with aneurysmal subarachnoid hemorrhage (SAH) is unknown. In patients with cerebral vasospasm, anemia may increase susceptibility to ischemic injury; conversely, RBCT may worsen outcome given known deleterious effects.

OBJECTIVE

To examine the association between RBCT, delayed cerebral ischemia (DCI), vasospasm, and outcome after SAH.

METHODS

A total of 421 consecutive patients with SAH, admitted to a neurocritical care unit at a university-affiliated hospital and who underwent surgical occlusion of their ruptured aneurysm were retrospectively identified from a prospective observational database. Propensity score methods were used to reduce the bias associated with treatment selection.

RESULTS

Two hundred and sixty-one patients (62.0%) received an RBCT. Angiographic vasospasm (odds ratio [OR] 1.6; 95% confidence interval [CI], 1.1-2.3; P = 0.025) but not severe angiographic spasm, DCI, or delayed infarction was associated with RBCT. A total of 283 patients (67.2%) experienced a favorable outcome, defined as good or moderately disabled on the Glasgow Outcome Scale; 47 (11.2%) were severely disabled or vegetative and 91 patients (21.6%) were dead at 6-month follow-up. Among patients who survived ≥2 days, RBCT was associated with unfavorable outcome (OR, 2.6; 95% CI, 1.6-4.1). Transfusion of ≥3 units of blood was associated with an increased incidence of unfavorable outcome. Propensity analysis to control for the probability of exposure to RBCT conditional on observed covariates measured before RBCT indicates that RBCT is associated with unfavorable outcome in the absence of DCI (OR, 2.17; 95% CI, 1.56-3.01; P < 0.0001) but not when DCI is present (OR, 0.82; 95% CI, 0.35-1.92; P = 0.65).

CONCLUSIONS

Blood transfusions are associated with unfavorable outcome after SAH particularly when DCI is absent. Propensity analysis suggests that RBCT may be associated with poor outcome rather than being a marker of disease severity. However, when DCI is present, RBCT may help improve outcome.

Transfusion of red blood cells in patients with traumatic brain injuries admitted to Canadian trauma health centres: a multicentre cohort study

BACKGROUND

Optimisation of healthcare practices in patients sustaining a traumatic brain injury is of major concern given the high incidence of death and long-term disabilities. Considering the brain's susceptibility to ischaemia, strategies to optimise oxygenation to brain are needed. While red blood cell (RBC) transfusion is one such strategy, specific RBC strategies are debated. We aimed to evaluate RBC transfusion frequency, determinants of transfusions and associated clinical outcomes.

METHODS

We conducted a retrospective multicentre cohort study using data from the National Trauma Registry of Canada. Patients admitted with moderate or severe traumatic brain injury to participating hospitals between April 2005 and March 2013 were eligible. Patient information on blood products, comorbidities, interventions and complications from the Discharge Abstract Database were linked to the National Trauma Registry data. Relative weights analyses evaluated the contribution of each determinant. We conducted multivariate robust Poisson regression to evaluate the association between potential determinants, mortality, complications, hospital-to-home discharge and RBC transfusion. We also used proportional hazard models to evaluate length of stay for time to discharge from ICU and hospital.

RESULTS

Among the 7062 patients with traumatic brain injury, 1991 patients received at least one RBC transfusion during their hospital stay. Female sex, anaemia, coagulopathy, sepsis, bleeding, hypovolemic shock, other comorbid illnesses, serious extracerebral trauma injuries were all significantly associated with RBC transfusion. Serious extracerebral injuries altogether explained 61% of the observed variation in RBC transfusion. Mortality (risk ratio (RR) 1.23 (95% CI 1.13 to 1.33)), trauma complications (RR 1.38 (95% CI 1.32 to 1.44)) and discharge elsewhere than home (RR 1.88 (95% CI 1.75 to 2.04)) were increased in patients who received RBC transfusion. Discharge from ICU and hospital were also delayed in transfused patients.

CONCLUSIONS

RBC transfusion is common in patients with traumatic brain injury and associated with unfavourable outcomes. Trauma severity is an important determinant of RBC transfusion. Prospective studies are needed to further evaluate optimal transfusion strategies in traumatic brain injury.

Blood transfusion indications in neurosurgical patients: A systematic review

Neurosurgical procedures can be complicated by significant blood losses that have the potential to decrease tissue perfusion to critical brain tissue. Red blood cell transfusion is used in a variety of capacities both inside, and outside, of the operating room to prevent untoward neurologic damage. However, evidence-based guidelines concerning thresholds and indications for transfusion in neurosurgery remain limited. Consequently, transfusion practices in neurosurgical patients are highly variable and based on institutional experiences. Recently, a paradigm shift has occurred in neurocritical intensive care units, whereby restrictive transfusion is increasingly favored over liberal transfusion but the ideal strategy remains in clinical equipoise. The authors of this study perform a systematic review of the literature with the objective of capturing the changing landscape of blood transfusion indications in neurosurgical patients.

Critical care in acute ischemic stroke

Most ischemic strokes are managed on the ward or on designated stroke units. A significant proportion of patients with ischemic stroke require more specialized care. Several studies have shown improved outcomes for patients with acute ischemic stroke when neurocritical care services are available. Features of acute ischemic stroke patients requiring intensive care unit-level care include airway or respiratory compromise; large cerebral or cerebellar hemisphere infarction with swelling; infarction with symptomatic hemorrhagic transformation; infarction complicated by seizures; and a large proportion of patients require close management of blood pressure after thrombolytics. In this chapter, we discuss aspects of acute ischemic stroke care that are of particular relevance to a neurointensivist, covering neuropathology, neurodiagnostics and imaging, blood pressure management, glycemic control, temperature management, and the selection and timing of antithrombotics. We also focus on the care of patients who have received intravenous thrombolysis or mechanical thrombectomy. Complex clinical decision making in decompressive hemicraniectomy for hemispheric infarction and urgent management of basilar artery thrombosis are specifically addressed.

Aneurysmal SubArachnoid Hemorrhage-Red Blood Cell Transfusion And Outcome (SAHaRA): a pilot randomised controlled trial protocol

INTRODUCTION

Anaemia is common in aneurysmal subarachnoid haemorrhage (aSAH) and is a potential critical modifiable factor affecting secondary injury. Despite physiological evidence and management guidelines that support maintaining a higher haemoglobin level in patients with aSAH, current practice is one of a more restrictive approach to transfusion. The goal of this multicentre pilot trial is to determine the feasibility of successfully conducting a red blood cell (RBC) transfusion trial in adult patients with acute aSAH and anaemia (Hb ≤100 g/L), comparing a liberal transfusion strategy (Hb ≤100 g/L) with a restrictive strategy (Hb ≤80 g/L) on the combined rate of death and severe disability at 12 months.

METHODS

Design This is a multicentre open-label randomised controlled pilot trial at 5 academic tertiary care centres. Population We are targeting adult aSAH patients within 14 days of their initial bleed and with anaemia (Hb ≤110 g/L). Randomisation Central computer-generated randomisation, stratified by centre, will be undertaken from the host centre. Randomisation into 1 of the 2 treatment arms will occur when the haemoglobin levels of eligible patients fall to ≤100 g/L. Intervention Patients will be randomly assigned to either a liberal (threshold: Hb ≤100 g/L) or a restrictive transfusion strategy (threshold: Hb ≤80 g/L). Outcome Primary: Centre randomisation rate over the study period. Secondary: (1) transfusion threshold adherence; (2) study RBC transfusion protocol adherence; and (3) outcome assessment including vital status at hospital discharge, modified Rankin Score at 6 and 12 months and Functional Independence Measure and EuroQOL Quality of Life Scale scores at 12 months. Outcome measures will be reported in aggregate.

ETHICS AND DISSEMINATION

The study protocol has been approved by the host centre (OHSN-REB 20150433-01H). This study will determine the feasibility of conducting the large pragmatic RCT comparing 2 RBC transfusion strategies examining the effect of a liberal strategy on 12-month outcome following aSAH.

TRIAL REGISTRATION NUMBER

NCT02483351; Pre-results.

The effects of anaemia and transfusion on patients with traumatic brain injury: A review

BACKGROUND

Anaemia in traumatic brain injury (TBI) is frequently encountered. Neurosurgical texts continue to recommend transfusion for hematocrit below 30%, despite clear evidence to do so. Transfusion should increase oxygen delivery to the brain, but it may also increase morbidity and mortality.

METHODS

This study reviewed the relevant literature to better understand the risks of anaemia and benefits of correction of anaemia by transfusion.

RESULTS

Of the 21 studies reviewed, eight found that anaemia was harmful to patients with TBI; five found no significant outcome; seven found transfusion was associated with higher rates of morbidity and mortality; two found that transfusion lowered mortality and increased brain tissue oxygen levels; and ten found no correlation between transfusion and outcome. However, the levels of anaemia severity and the outcome measurements varied widely and the majority of outcomes focused on crude measurements rather than detailed functional assessments.

CONCLUSIONS

No division of response based on gender difference or impact of anaemia in the post-hospital treatment setting was observed. A randomized control trial is recommended to determine the impact of anaemia and transfusion on detailed outcome assessment in comparison of transfusion thresholds ranging from ≤ 7 g dL^-1 to ≤ 9 g dL^-1 in patients with moderate-to-severe TBI.

The Effect of Red Blood Cell Transfusion on Cerebral Autoregulation in Patients with Severe Traumatic Brain Injury

BACKGROUND

Red blood cell (RBC) transfusion is associated with inconsistent changes in brain tissue oxygenation (PbO2). Previous studies have failed to consider alterations in cerebral autoregulation. Our objective was to investigate the effect of RBC transfusion on cerebral autoregulation, as measured by pressure reactivity index (PRx).

METHODS

Retrospective analysis of 28 severe traumatic brain injury (TBI) patients from a prospective registry between 2007 and 2014. We recorded hemoglobin (Hb) concentration, intracranial pressure, PbO2, cerebral perfusion pressure, PRx, and cerebral lactate/pyruvate ratio for 6 h before and after RBC transfusion. We also recorded body temperature, PaO2, PCO2, pH, and fraction of inspired oxygen. Subgroups of normoxia (PbO2 >20 mmHg) and hypoxia (PbO2 <20 mmHg) prior to transfusion were defined a priori.

RESULTS

The median age was 36 years [interquartile range (IQR) 27-49], 32% were female. The median admission Glasgow Coma score was 5 (IQR 4-9) and injury severity score was 16 (IQR 9-21). Overall, mean Hb concentration [80 g/L (SD 7) to 89 g/L (SD 8), p < 0.001] and PbO2 increased [23.5 mmHg (SD 8) to 25.0 mmHg (SD 9), p = 0.033] following transfusion. PRx increased post-transfusion [0.028 (SD 0.29) to 0.11 (SD 0.24), p = 0.034], indicating worsening cerebrovascular pressure reactivity. In patients with mean PbO2 >20 mmHg pre-transfusion (n = 20), the PRx increased significantly [-0.052 (SD 0.24) to 0.079 (SD 0.22), p = 0.007] but did not change in patients with PbO2 <20 mmHg: PRx [0.22 (SD 0.34) to 0.18 (SD 0.30), p = 0.36].

CONCLUSION

RBC transfusion in severe TBI patients results in worsening PRx, indicating impaired cerebral autoregulation.

Adults with sickle cell disease may perform cognitive tests as well as controls when processing speed is taken into account: a preliminary case-control study

AIMS

This study aimed to: (1) evaluate cognitive function among adults with sickle cell disease using a computer-administered neuropsychological test; and (2) replicate previously identified differences in processing speed between patients with sickle cell disease and controls.

BACKGROUND

Previous evidence suggests that, compared with controls, adult patients with sickle cell disease have poorer cognitive functioning across most domains but the most significant deficits appear to be in the area of processing speed.

DESIGN

Cross-sectional case-control study conducted from June 2008-June 2010.

METHODS

Cognitive functioning was measured using computerized, self-administered, neuropsychological tests among 31 patients with sickle cell disease and 17 controls matched for age, gender and race. The assessment averaged 30 minutes and scores were recorded for seven computerized tests: verbal and visual memory, finger tapping, symbol digit coding, Stroop test, shifting attention and continuous performance.

RESULTS

Patients with sickle cell disease scored 10·76 points lower on the CNS Vital Signs processing speed domain than controls. Although non-significant, patients scored 5·73 points lower on the full index than controls but after adjusting for processing speed, mean scores for patients were 3 points greater compared with controls. Differences in executive functioning and attention were not significant and memory did not differ between groups.

CONCLUSION

Using a brief, computer-administered 30-minute neuropsychological test, we were able to replicate previous findings showing a greater than 10-point deficit in processing speed among patients with sickle cell disease. When differences in processing speed are taken into account, patients perform equally well or better than controls on cognitive tasks.

Hemoglobin Area and Time Index Above 90 g/L are Associated with Improved 6-Month Functional Outcomes in Patients with Severe Traumatic Brain Injury

PURPOSE

There is conflicting data on the relationship between anemia and outcomes in patients with traumatic brain injuries (TBI). The objective of this study was to determine if the proportion of time and area under the hemoglobin-time curve of ≥90 g/L are independently associated with 6-month functional outcomes.

METHODS

Retrospective cohort study of 116 patients with a severe TBI who underwent invasive neuromonitoring between June 2006 and December 2013. Hemoglobin area (HAI) and time (HTI) indices were calculated by dividing the total area, or time, under the hemoglobin-time curve at 90 g/L or above by the total duration of monitoring. Multivariable log-binomial regression was used to model the association between HAI or HTI and 6 month favorable neurologic outcome (Glasgow Outcome Score 4 or 5).

RESULTS

Patients had a mean age of 38 years (SD 16) with a median admission Glasgow Coma Scale of 6 (IQR 4-7). There were 1523 hemoglobin measurements and 523 monitoring days. Patients had a hemoglobin ≥90 g/L for a median of 70 % (IQR 37-100) of the time. Each 10 g/L increase in HAI (RR 1.23, 95 %CI 1.04-1.44, P = 0.011), and 10 % increase in HTI (1.10, 95 %CI 1.04-1.16, P < 0.001) were associated with improved neurologic outcome. Thirty-one patients (27 %) received a transfusion with the median pre-transfusion hemoglobin being 81 g/L (IQR 76-87).

CONCLUSIONS

In patients with severe TBI, increased area under the curve and percentage of time that the hemoglobin concentration was ≥90 g/L, were associated with improved neurologic outcomes.

The association between post resuscitation hemoglobin level and survival with good neurological outcome following Out Of Hospital cardiac arrest

AIMS

to explore the association between post return of spontaneous circulation (ROSC) hemoglobin level and survival with good neurological outcome following out-of-hospital cardiac arrest.

METHODS

We studied adults with non-traumatic out-of-hospital cardiac arrest who achieved ROSC within 50min of collapse. We quantified the association between post ROSC hemoglobin level and good neurological outcome (defined as Cerebral Performance Category score of 1or 2), using multivariate logistic regression analyses. The impact of Post ROSC hemoglobin level ≥10gdl(-1) and time varying hemoglobin level ≥10gdl(-1) on time to Survival with good outcome was assessed using Cox proportional hazard models.

RESULTS

Of 931 cardiac arrest patients, 146 (16%) achieved ROSC and 30 survived to discharge with a good neurological outcome. Of those with post ROSC hemoglobin level ≥10gdl(-1), 28% (27/98) had good outcome, whereas of those with level <10mgdl(-1) only 6% (3/48) had good outcome (CPC<3, P=0.003). The use of blood transfusions and therapeutic hypothermia were comparable in both good and bad outcome groups. An immediate post ROSC hemoglobin level ≥10gdl(-1) was significantly associated with good neurological outcome (AOR 8.31 95% CI 1.89-36.52 P=0.005). Patients with post ROSC hemoglobin ≥10gdl(-1) were more likely to achieve good outcome earlier (HR 6.02 95% CI 1.75-20.72 P=0.004).

CONCLUSIONS

Post ROSC hemoglobin level ≥10gdl(-1) is associated with survival with good neurological outcome. The importance of time to achieve such level and the role of blood transfusion warrants further investigation.