Anemia and cerebral outcomes: many questions, fewer answers

Perioperative transfusion management in craniotomies: A national survey, a starting point for the evaluation of improvements in health care

OBJECTIVE

To assess the perioperative management of haemostasis and transfusion practices in adult patients undergoing craniotomies.

METHOD

Online questionnaire addressed to Spanish anaesthesiologists and promoted by the Neurosciences and Haemostasis, Transfusion Medicine and Fluid Therapy Sections of SEDAR. The questionnaire was sent by email and social media, and was active between June and October 2022.

RESULTS

We obtained 155 responses from 67 centres; 59.4% perform >100 craniotomies per year. 61.7% were regularly involved in neuroanaesthesiology. Only 21.9% of respondents had pre-anaesthesia assessment performed by a member of that section, and in most of them (83.0%) the assessment was performed ≤3 weeks in advance. Of the respondents with Patient Blood Management programmes, 58.2% had no specific protocols for craniotomies. 90.3% reported that haemoconcentrates are systematically reserved. A lower platelet limit of 100,000/µL is considered acceptable by 76.8%. 99.4% of respondents discontinued antiplatelet medication based on half-life. Only 23.9% respondents routinely discontinued non-steroidal anti-inflammatory drugs. The transfusion threshold for haemoglobin during surgical bleeding was <10 g/dL in 18.7%, <9 g/dL in 38.1%, <8 g/dL in 38.7% and <7 g/dL in 4.5%.

CONCLUSIONS

Preoperative anaemia screening and treatment programmes are not implemented and blood product reserves are systematised in patients scheduled for craniotomy. Anti-aggregation therapy is discontinued according to the half-life of the drug without checking platelet functionality.

Hemoglobin in large vessel occlusion: Look further than collaterals

BACKGROUND

Abnormal hemoglobin (Hb) levels lead to poorer outcomes in ischemic stroke, though the mechanisms remain elusive. We aimed to study the role of Hb on imaging and clinical outcomes, namely on collaterals as it is a known mediator of infarct growth.

METHODS

Retrospective cohort study of patients with large vessel occlusion ischemic stroke admitted to our center. Demographics, clinical and imaging variables were collected, particularly baseline hemoglobin, presence of anemia and collateral score. Collaterals were scored from 0 to 3 and defined as poor if 0-1. Multivariable analyses were performed for collateral score and clinical outcomes (3-month mortality and good prognosis).

RESULTS

We included 811 patients, 215 (26.5 %) with anemia. Patients with anemia were older, had more comorbidities and more severe strokes. Hemoglobin levels and anemia were not associated with collateral score (OR 0.97, 95 % CI 0.89-1.05, p = 0.414 and OR 0.89, 95 % CI 0.64-1.24, p = 0.487, respectively) nor with poor collaterals (OR 0.96, 95 % CI 0.88-1.05, p = 0.398 and OR 0.86, 95 % CI 0.60-1.23, p = 0.406, respectively). Hb levels were associated with 3-month mortality (OR 0.85, 95 % CI 0.76-0.96, p = 0.008).

CONCLUSION

Hemoglobin or anemia were not found to be associated with collateral status. Our results raise further questions regarding the pathophysiology of anemia and outcomes in ischemic stroke, highlighting the need for future research.

Risk Factors for Stroke Development After Thoracic Aortic Surgery

OBJECTIVES

Stroke after thoracic aortic surgery is a complication that is associated with poor outcomes. The aim is to characterize the intraoperative risk factors for stroke development.

DESIGN

A retrospective analysis.

SETTING

Tertiary, high-volume cardiac surgery center.

PARTICIPANTS

Patients who had surgical repair of thoracic aortic diseases from January 1, 2017, through December 31, 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 704 patients were included, of whom 533 had ascending aortic aneurysms, and 171 had type A aortic dissection. The incidence of postoperative stroke was 4.5% (95% CI 2.9%-6.6%) for ascending aortic aneurysms compared with 12.3% (95% CI 7.8%-18.16%) in type-A aortic dissections. Patients who developed postoperative strokes had significantly lower intraoperative hemoglobin median (7.5 gm/dL [IQR 6.8-8.6] v 8.55 gm/dL [IQR 7.3-10.0]; p < 0.001). The median cardiopulmonary bypass time was 185 minutes (IQR 136-328) in the stroke group versus 156 minutes (IQR 113-206) in the nonstroke group (p = 0.014). Circulatory arrest was used in 57.8% versus 38.5% of the nonstroke patients (p = 0.017). The initial temperature after leaving the operating room was lower, with a median of 35.0°C (IQR 34-35.92) in the stroke group versus 35.5°C (IQR 35-36) in the nonstroke cohort (p = 0.021).

CONCLUSIONS

This single-center study highlighted the potential importance of intra-operative factors in preventing stroke. Lower hemoglobin, longer duration of cardiopulmonary bypass, deep hypothermic circulatory arrest, and postoperative hypothermia are potential risk factors for postoperative stroke. Further studies are needed to prevent this significant complication in patients with thoracic aortic diseases.

Methemoglobin as a marker of acute anemic stress in cardiac surgery

Biological evidence supports plasma methemoglobin as a biomarker for anemia-induced tissue hypoxia. In this translational planned substudy of the multinational randomized controlled transfusion thresholds in cardiac surgery (TRICS-III) trial, which included adults undergoing cardiac surgery requiring cardiopulmonary bypass with a moderate-to-high risk of death, we investigated the relationship between perioperative hemoglobin concentration (Hb) and methemoglobin; and evaluated its association with postoperative outcomes. The primary endpoint was a composite of death, myocardial infarction, stroke, and severe acute kidney injury at 28 days. We observe weak non-linear associations between decreasing Hb and increasing methemoglobin, which were strongest in magnitude at the post-surgical time point. Increased levels of post-surgical methemoglobin were associated with a trend toward an elevated risk for stroke and exploratory neurological outcomes. Our generalizable study demonstrates post-surgical methemoglobin may be a marker of anemia-induced organ injury/dysfunction, and may have utility for guiding personalized approaches to anemia management. Clinicaltrials.gov registration NCT02042898.

Anemia and Erythrocyte Indices Are Associated With Neurocognitive Performance Across Multiple Ability Domains in Adults With HIV

BACKGROUND

Anemia is linked to neurocognitive impairment (NCI) in people with HIV (PWH), but its impact within specific ability domains, and in diverse populations with HIV, is uncertain.

METHODS

Participants included 1339 PWH enrolled in observational HIV cohort studies with a mean of 3 comprehensive neurocognitive assessments over 30 months. Global and domain-specific neurocognitive function were assessed by the global deficit score and domain deficit score (GDS and DDS, respectively) or as GDS-defined or DDS-defined NCI (GDS ≥ 0.5, DDS > 0.5). Time-dependent associations of anemia or red-cell indices with neurocognitive function were evaluated by multivariable regression.

RESULTS

The mean age at entry was 43.6 years (85% male, 23.9% Hispanic, 16.7% African ancestry by self-report, and 69.8% virally suppressed). Anemia occurred at entry in 297 (22.2%) and developed subsequently in another 129 (9.6%). Anemia (present in 26.8% of cognitively impaired PWH at entry) and lower hemoglobin were associated with higher (worse) GDS values; the association for anemia persisted after multivariable adjustment and in virally suppressed persons ( P < 0.0001). Anemia was also associated with reduced processing speed, motor function, learning, delayed recall, working memory (all P < 0.01), executive function ( P = 0.021), and verbal fluency ( P = 0.035), and these findings persisted in longitudinal analyses (adjusted P < 0.01 for all domains, except verbal fluency). Higher mean corpuscular volume and mean corpuscular hemoglobin were associated with less impairment in learning and recall (all P < 0.05).

CONCLUSIONS

Anemia in diverse and virally suppressed PWH associates with reduced neurocognitive performance in multiple domains, cross-sectionally and over time. The impact of identifying and treating anemia to prevent or slow neurocognitive decline in PWH should be prospectively evaluated.

Development and Performance Evaluation of a Clinical Predictive Model to Estimate the Risk of Red Blood Cell Requirements in Brain Tumor Surgery

BACKGROUND

The identification of factors associated with perioperative red blood cell (RBC) transfusion provides an opportunity to optimize the patient and surgical plan, and to guide perioperative crossmatch and RBC orders. We examined the association among potential bleeding risk factors and RBC requirements to develop a novel predictive model for RBC transfusion in patients undergoing brain tumor surgery.

METHODS

This retrospective study included 696 adults who underwent brain tumor surgery between 2008 and 2018. Multivariable logistic regression with backward stepwise selection for predictor selection was used during modeling. Model performance was evaluated using area under the receiver operating characteristic curve, and calibration was evaluated with Hosmer-Lemeshow goodness-of-fit χ 2 -estimate.

RESULTS

Preoperative hemoglobin level was inversely associated with the probability of RBC transfusion (odds ratio [OR]: 0.50; 95% confidence interval [CI]: 0.39-0.63; P <0.001). The need for RBC transfusion was also greater in patients who had a previous craniotomy (OR: 2.71; 95% CI: 1.32-5.57; P =0.007) and in those with larger brain tumor volume (OR: 1.01; 95% CI: 1.00-1.02; P =0.009). The relationship between number of planned craniotomy sites and RBC transfusion was not statistically significant (OR: 2.11; 95% CI: 0.61-7.32; P =0.238). A predictive model for RBC requirements was built using these 4 variables. The area under the receiver operating characteristic curve was 0.79 (95% CI: 0.70-0.87; P <0.001) showing acceptable calibration for predicting RBC transfusion requirements.

CONCLUSIONS

RBC requirements in patients undergoing brain tumor surgery can be estimated with acceptable accuracy using a predictive model based on readily available preoperative clinical variables. This predictive model could help to optimize both individual patients and surgical plans, and to guide perioperative crossmatch orders.

Low hemoglobin is associated with worse outcomes via larger hematoma volume in intracerebral hemorrhage due to systemic disease

Whether hemoglobin is associated with outcomes of a specific subtype of intracerebral hemorrhage (ICH) is unknown. A total of 4643 patients with ICH from a multicenter cohort were included in the analysis (64.0% male; mean age [SD], 58.3 [15.2] year), of whom 1319 (28.4%) had anemia on admission. The unsupervised consensus cluster method was employed to classify the patients into three clusters. The patients of cluster 3 were characterized by a high frequency of anemia (85.3%) and mainly composed of patients of systemic disease ICH subtype (SD-ICH; 90.0%) according to the SMASH-U etiologies. In SD-ICH, a strong interaction effect was observed between anemia and 3-month death (adjusted odds ratio [aOR] 4.33, 95% confidence interval [CI] 1.60-11.9, p = 0.004), and the hemoglobin levels were linearly associated with 3-month death (aOR 0.75, 95% CI 0.60-0.92; p = 0.009), which was partially mediated by larger baseline hematoma volume (p = 0.008). This study demonstrated a strong linear association between low hemoglobin levels and worse outcomes in SD-ICH, suggesting that hemoglobin-elevating therapy might be extensively needed in a specific subtype of ICH.

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.

Association between aspirin-induced hemoglobin decline and outcome after acute ischemic stroke in G6PD-deficient patients

Aims

The risk of hemoglobin decline induced by low‐dose aspirin in glucose‐6‐phosphate dehydrogenase (G6PD) deficiency remains unknown, and its influence on stroke outcome remains to be investigated. This study aimed to evaluate the effect of G6PD deficiency on hemoglobin level during aspirin treatment and its association with outcome after acute ischemic stroke.

Methods

In total, 279 patients (40 G6PD‐deficient and 239 G6PD‐normal) with acute ischemic stroke treated with aspirin 100 mg/day from a cohort study were examined. The primary safety endpoint was a hemoglobin decline ≥25 g/L or 25% from baseline within 14 days after aspirin treatment. Poor outcomes were defined as a modified Rankin Scale score ≥2 at 3 months. The χ² test was used to compare stroke outcomes, and multivariate logistic regression analyses were performed to analyze the association between hemoglobin level and outcomes.

Results

The G6PD‐deficient group had lower baseline hemoglobin and tended to develop comorbid pulmonary infection more frequently (p < 0.05). The proportion of patients with hemoglobin decline ≥25 g/L or 25% from baseline (15.0% vs. 3.3%; p = 0.006) and anemia (30.0% vs. 14.6%; p = 0.016) after aspirin treatment was higher in the G6PD‐deficient group, which was accompanied by a more significant bilirubin increase. The rate of poor functional outcomes at 3 months after acute ischemic stroke was higher in the G6PD‐deficient group (Risk ratio = 1.31 [95% confidence interval (CI) = 1.10–1.56]; p = 0.017). Confounder‐adjusted analysis showed that lower hemoglobin levels (odds ratio = 0.98 [95% CI = 0.96–0.99]; adjusted p = 0.009) increased the risk of poor functional outcomes.

Conclusion

Hemoglobin decrease with bilirubin increase after aspirin treatment in patients with G6PD deficiency suggests hemolysis, which may influence stroke prognosis. The risk of hemoglobin decline should be carefully monitored in G6PD‐deficient patients with ischemic stroke taking aspirin.

Clinical Outcome and Risk Factors of Red Blood Cell Transfusion in Patients Undergoing Elective Primary Meningioma Resection

Simple Summary

The transfusion of red blood cells (RBC) in patients undergoing major elective cranial surgery is associated with increased morbidity and mortality. This study sought to identify the clinical outcome of RBC transfusions in skull base and non-skull base meningioma patients including the identification of risk factors for RBC transfusion. Data underline that preoperative anaemia rate was significantly higher in transfused patients (17.7%) compared to patients without RBC transfusion (6.2%). We could further show that RBC transfusion was associated with increased postoperative complications and increased hospital length of stay. After multivariate analyses, risk factors for RBC transfusion were preoperative American Society of Anaesthesiologists (ASA) physical status score, tumor size, surgical time, and intraoperative blood loss. We concluded that blood loss due to large tumors or localization near large vessels are the main triggers for RBC transfusion in meningioma patients paired with a potential preselection that masks the effect of preoperative anaemia in multivariate analysis. So far, this has not been investigated in a large cohort (n = 423) of skull base and non-skull base meningioma patients.

Abstract

Transfusion of red blood cells (RBC) in patients undergoing major elective cranial surgery is associated with increased morbidity, mortality and prolonged hospital length of stay (LOS). This retrospective single center study aims to identify the clinical outcome of RBC transfusions on skull base and non-skull base meningioma patients including the identification of risk factors for RBC transfusion. Between October 2009 and October 2016, 423 patients underwent primary meningioma resection. Of these, 68 (16.1%) received RBC transfusion and 355 (83.9%) did not receive RBC units. Preoperative anaemia rate was significantly higher in transfused patients (17.7%) compared to patients without RBC transfusion (6.2%; p = 0.0015). In transfused patients, postoperative complications as well as hospital LOS was significantly higher (p < 0.0001) compared to non-transfused patients. After multivariate analyses, risk factors for RBC transfusion were preoperative American Society of Anaesthesiologists (ASA) physical status score (p = 0.0247), tumor size (p = 0.0006), surgical time (p = 0.0018) and intraoperative blood loss (p < 0.0001). Kaplan-Meier curves revealed significant influence on overall survival by preoperative anaemia, RBC transfusion, smoking, cardiovascular disease, preoperative KPS ≤ 60% and age (elderly ≥ 75 years). We concluded that blood loss due to large tumors or localization near large vessels are the main triggers for RBC transfusion in meningioma patients paired with a potential preselection that masks the effect of preoperative anaemia in multivariate analysis. Further studies evaluating the impact of preoperative anaemia management for reduction of RBC transfusion are needed to improve the clinical outcome of meningioma patients.

Socio-emotional and adaptive behaviour in children treated for severe anaemia at Lira Regional Referral Hospital, Uganda: a prospective cohort study

BACKGROUND

Severe anaemia is a global public health challenge commonly associated with morbidity and mortality among children < 5 years of age in Sub-Saharan Africa. However, less is known about the behavioural performance of children < 5 years surviving severe anaemia in low resource settings. We investigated social-emotional and adaptive behaviour in children < 5 years diagnosed with severe anaemia in Northern Uganda.

METHODS

We conducted a hospital based prospective cohort study among children 6-42 months who were treated for severe anaemia (n = 171) at Lira Regional Referral Hospital, Uganda. Socio-emotional and adaptive behaviour were assessed 14 days post discharge using the Bayley Scales of Infant and Toddler Development, 3rd edition. Age-adjusted z-scores for each domain were calculated using scores from healthy community children (n = 88) from the same environment for each age category. Multiple linear regression was used to compare z-scores in the social-emotional and adaptive behaviour scales between the two groups after adjusting for weight-for-age z-score, social economic status, mother's education, father's education and father's employment on all the scales.

RESULTS

Compared with healthy community controls, children with severe anaemia had poorer [adjusted mean scores (standard error)], socio-emotional [- 0.29, (0.05) vs. 0.01, (0.08), P = 0.002]; but not overall/ composite adaptive behaviour [- 0.10, (0.05) vs. - 0.01, (0.07), P = 0.343]. Within the adaptive behaviour subscales, children with SA displayed significantly poorer scores on the community use [adjusted mean score (standard error)], [- 0.63, (0.10) vs. - 0.01, (0.13), P < 0.001]; and leisure [- 0.35, (0.07) vs. - 0.02, (0.07), P = 0.036] skills.

CONCLUSION

This study suggests that severe anaemia in children < 5 years is associated with poor social-emotional scores in the short-term post clinical recovery in Northern Uganda. We recommend long-term follow-up to determine the course of these problems and appropriate interventions to reduce the behavioural burden among children < 5 years surviving severe anaemia in Uganda.

Effect of haemoglobin levels on outcome in intravenous thrombolysis-treated stroke patients

INTRODUCTION

Alterations in haemoglobin levels are frequent in stroke patients. The prognostic meaning of anaemia and polyglobulia on outcomes in patients treated with intravenous thrombolysis is ambiguous.

PATIENTS AND METHODS

In this prospective multicentre, intravenous thrombolysis register-based study, we compared haemoglobin levels on hospital admission with three-month poor outcome (modified Rankin Scale 3-6), mortality and symptomatic intracranial haemorrhage (European Cooperative Acute Stroke Study II-criteria (ECASS-II-criteria)). Haemoglobin level was used as continuous and categorical variable distinguishing anaemia (female: <12 g/dl; male: <13 g/dl) and polyglobulia (female: >15.5 g/dl; male: >17 g/dl). Anaemia was subdivided into mild and moderate/severe (female/male: <11 g/dl). Normal haemoglobin level (female: 12.0-15.5 g/dl, male: 13.0-17.0 g/dl) served as reference group. Unadjusted and adjusted odds ratios with 95% confidence intervals were calculated with logistic regression models.

RESULTS

Among 6866 intravenous thrombolysis-treated stroke patients, 5448 (79.3%) had normal haemoglobin level, 1232 (17.9%) anaemia - of those 903 (13.2%) had mild and 329 (4.8%) moderate/severe anaemia - and 186 (2.7%) polyglobulia. Anaemia was associated with poor outcome (ORadjusted 1.25 (1.05-1.48)) and mortality (ORadjusted 1.58 (1.27-1.95)). In anaemia subgroups, both mild and moderate/severe anaemia independently predicted poor outcome (ORadjusted 1.29 (1.07-1.55) and 1.48 (1.09-2.02)) and mortality (ORadjusted 1.45 (1.15-1.84) and ORadjusted 2.00 (1.46-2.75)). Each haemoglobin level decrease by 1 g/dl independently increased the risk of poor outcome (ORadjusted 1.07 (1.02-1.11)) and mortality (ORadjusted 1.08 (1.02-1.15)). Anaemia was not associated with occurrence of symptomatic intracranial haemorrhage. Polyglobulia did not change any outcome.

DISCUSSION

The more severe the anaemia, the higher the probability of poor outcome and death. Severe anaemia might be a target for interventions in hyperacute stroke.

CONCLUSION

Anaemia on admission, but not polyglobulia, is a strong and independent predictor of poor outcome and mortality in intravenous thrombolysis-treated stroke patients.

Influence of Hemoglobin Concentration on Stroke Recurrence and Composite Vascular Events

Background and Purpose- We evaluated whether hemoglobin concentration at admission was associated with stroke recurrence and composite vascular events (stroke, myocardial infarction, and vascular death) in acute ischemic stroke. Methods- We collected data from patients with acute ischemic stroke or transient ischemic attack from a multicenter stroke registry database in Korea. The association of hemoglobin concentration with 1-year stroke recurrence and composite vascular events was evaluated with respect to age, presence of cerebral artery stenosis, stroke severity, and stroke subtype. Results- Hemoglobin levels were inversely associated with stroke recurrence and composite vascular events. One-year rates of stroke recurrence and composite vascular events were significantly higher in patients with anemia or moderate anemia. In multivariable analyses, moderate anemia remained an independent predictor of stroke recurrence (adjusted hazard ratio, 1.43 [95% CI, 1.16-1.75]) and composite vascular events (adjusted hazard ratio, 1.26 [95% CI, 1.07-1.48]). Moderate anemia increased the risk of composite vascular events in patients with mild-to-moderate stroke severity (National Institutes of Health Stroke Scale score <16, P=0.01 for interaction). Conclusions- Hemoglobin concentration could be an independent predictor of stroke recurrence and composite vascular events.

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.

Genetic Analysis of Babesia Isolates from Cattle with Clinical Babesiosis in Sri Lanka

Bovine babesiosis is a serious threat to the cattle industry. We prepared blood DNA samples from 13 cattle with clinical babesiosis from the Badulla (n = 8), Jaffna (n = 3), and Kilinochchi (n = 2) districts in Sri Lanka. These DNA samples tested positive in PCR assays specific for Babesiabovis (n = 9), Babesia bigemina (n = 9), and Babesiaovata (n = 1). Twelve cattle were positive for B. bovis and/or B. bigemina One cow was negative for the tested Babesia species but was positive for Babesia on microscopic examination; the phylogenetic positions of 18S rRNA and cytochrome oxidase subunit III gene sequences suggested that the cow was infected with Babesia sp. Mymensingh, which was recently reported from a healthy cow in Bangladesh. We then developed a novel Babesia sp. Mymensingh-specific PCR assay and obtained positive results for one other sample. Analysis of gene sequences from the cow with positive B. ovata-specific PCR results demonstrated that the animal was infected not with B. ovata but with Babesia sp. Hue-1, which was recently reported from asymptomatic cattle in Vietnam. The virulence of Babesia sp. Hue-1 is unclear, as the cow was coinfected with B. bovis and B. bigemina However, Babesia sp. Mymensingh probably causes severe clinical babesiosis, as it was the sole Babesia species detected in a clinical case. The present study revealed the presence of two bovine Babesia species not previously reported in Sri Lanka, plus the first case of severe bovine babesiosis caused by a Babesia species other than B. bovis, B. bigemina, and Babesiadivergens.

Pathogenesis and Treatment Options of Cancer Related Anemia: Perspective for a Targeted Mechanism-Based Approach

Cancer-related anemia (CRA) is a common sign occurring in more than 30% of cancer patients at diagnosis before the initiation of antineoplastic therapy. CRA has a relevant influence on survival, disease progression, treatment efficacy, and the patients' quality of life. It is more often detected in patients with advanced stage disease, where it represents a specific symptom of the neoplastic disease, as a consequence of chronic inflammation. In fact, CRA is characterized by biological and hematologic features that resemble those described in anemia associated to chronic inflammatory disease. Proinflammatory cytokine, mainly IL-6, which are released by both tumor and immune cells, play a pivotal action in CRA etiopathogenesis: they promote alterations in erythroid progenitor proliferation, erythropoietin (EPO) production, survival of circulating erythrocytes, iron balance, redox status, and energy metabolism, all of which can lead to anemia. The discovery of hepcidin allowed a greater knowledge of the relationships between immune cells, iron metabolism, and anemia in chronic inflammatory diseases. Additionally, chronic inflammation influences a compromised nutritional status, which in turn might induce or contribute to CRA. In the present review we examine the multifactorial pathogenesis of CRA discussing the main and novel mechanisms by which immune, nutritional, and metabolic components affect its onset and severity. Moreover, we analyze the status of the art and the perspective for the treatment of CRA. Notably, despite the high incidence and clinical relevance of CRA, controlled clinical studies testing the most appropriate treatment for CRA are scarce, and its management in clinical practice remains challenging. The present review may be useful to indicate the development of an effective approach based on a detailed assessment of all factors potentially involved in the pathogenesis of CRA. This mechanism-based approach is essential for clinicians to plan a safe, targeted, and successful therapy, thereby promoting a relevant amelioration of patients' quality of life.

Targeted treatment in severe traumatic brain injury in the age of precision medicine

In recent years, much progress has been made in our understanding of traumatic brain injury (TBI). Clinical outcomes have progressively improved, but evidence-based guidelines for how we manage patients remain surprisingly weak. The problem is that the many interventions and strategies that have been investigated in randomized controlled trials have all disappointed. These include many concepts that had become standard care in TBI. And that is just for adult TBI; in children, the situation is even worse. Not only is pediatric care more difficult than adult care because physiological norms change with age, but also there is less evidence for clinical practice. In this article, we discuss the heterogeneity inherent in TBI and why so many clinical trials have failed. We submit that a key goal for the future is to appreciate important clinical differences between patients in their pathophysiology and their responses to treatment. The challenge that faces us is how to rationally apply therapies based on the specific needs of an individual patient. In doing so, we may be able to apply the principles of precision medicine approaches to the patients we treat.

MIF-Mediated Hemodilution Promotes Pathogenic Anemia in Experimental African Trypanosomosis

Animal African trypanosomosis is a major threat to the economic development and human health in sub-Saharan Africa. Trypanosoma congolense infections represent the major constraint in livestock production, with anemia as the major pathogenic lethal feature. The mechanisms underlying anemia development are ill defined, which hampers the development of an effective therapy. Here, the contribution of the erythropoietic and erythrophagocytic potential as well as of hemodilution to the development of T. congolense-induced anemia were addressed in a mouse model of low virulence relevant for bovine trypanosomosis. We show that in infected mice, splenic extramedullary erythropoiesis could compensate for the chronic low-grade type I inflammation-induced phagocytosis of senescent red blood cells (RBCs) in spleen and liver myeloid cells, as well as for the impaired maturation of RBCs occurring in the bone marrow and spleen. Rather, anemia resulted from hemodilution. Our data also suggest that the heme catabolism subsequent to sustained erythrophagocytosis resulted in iron accumulation in tissue and hyperbilirubinemia. Moreover, hypoalbuminemia, potentially resulting from hemodilution and liver injury in infected mice, impaired the elimination of toxic circulating molecules like bilirubin. Hemodilutional thrombocytopenia also coincided with impaired coagulation. Combined, these effects could elicit multiple organ failure and uncontrolled bleeding thus reduce the survival of infected mice. MIF (macrophage migrating inhibitory factor), a potential pathogenic molecule in African trypanosomosis, was found herein to promote erythrophagocytosis, to block extramedullary erythropoiesis and RBC maturation, and to trigger hemodilution. Hence, these data prompt considering MIF as a potential target for treatment of natural bovine trypanosomosis.

Bovine African trypanosomosis is a parasitic disease of veterinary importance that adversely affects the public health and economic development of sub-Saharan Africa. Anemia is a major cause of death associated with this disease. Yet, the mechanisms underlying anemia development are not elucidated, which hampers the design of effective therapeutic strategies. We show here that in a Trypanosoma congolense infection mouse model relevant for bovine trypanosomosis, red blood cells (RBCs) are generated in the spleen. This compensates for the impaired maturation of RBCs occurring in the bone marrow, the normal site of RBC generation, and for the destruction of RBCs taking place in the liver and the spleen. Instead, anemia results from an increase in blood volume (hemodilution). The immune molecule Macrophage Migration Inhibitory Factor (MIF) was found to drive RBC destruction, to block RBC maturation, as well as to trigger hemodilution. Iron accumulation in tissue due to sustained RBC destruction and hemodilution causes tissue damage, which culminates in the release of toxic molecules like bilirubin, in impaired production of blood detoxifying molecules like albumin, and in defective coagulation. Combined, these effects initiate multiple organ failure that can reduce the survival of infected mice. Given the unmet medical need for this parasite infection, our findings offer promise for improved treatment protocols in the field.

Impact of Hemoglobin Levels and Anemia on Mortality in Acute Stroke: Analysis of UK Regional Registry Data, Systematic Review, and Meta-Analysis

BACKGROUND

The impact of hemoglobin levels and anemia on stroke mortality remains controversial. We aimed to systematically assess this association and quantify the evidence.

METHODS AND RESULTS

We analyzed data from a cohort of 8013 stroke patients (mean±SD, 77.81±11.83 years) consecutively admitted over 11 years (January 2003 to May 2015) using a UK Regional Stroke Register. The impact of hemoglobin levels and anemia on mortality was assessed by sex-specific values at different time points (7 and 14 days; 1, 3, and 6 months; 1 year) using multiple regression models controlling for confounders. Anemia was present in 24.5% of the cohort on admission and was associated with increased odds of mortality at most of the time points examined up to 1 year following stroke. The association was less consistent for men with hemorrhagic stroke. Elevated hemoglobin was also associated with increased mortality, mainly within the first month. We then conducted a systematic review using the Embase and Medline databases. Twenty studies met the inclusion criteria. When combined with the cohort from the current study, the pooled population had 29 943 patients with stroke. The evidence base was quantified in a meta-analysis. Anemia on admission was found to be associated with an increased risk of mortality in both ischemic stroke (8 studies; odds ratio 1.97 [95% CI 1.57-2.47]) and hemorrhagic stroke (4 studies; odds ratio 1.46 [95% CI 1.23-1.74]).

CONCLUSIONS

Strong evidence suggests that patients with anemia have increased mortality with stroke. Targeted interventions in this patient population may improve outcomes and require further evaluation.

Anemia management after acute brain injury

Anemia is frequent among brain-injured patients, where it has been associated with an increased risk of poor outcome. The pathophysiology of anemia in this patient population remains multifactorial; moreover, whether anemia merely reflects a higher severity of the underlying disease or is a significant determinant of the neurological recovery of such patients remains unclear. Interestingly, the effects of red blood cell transfusions (RBCT) in moderately anemic patients remain controversial; although hemoglobin levels are increased, different studies observed only a modest and inconsistent improvement in cerebral oxygenation after RBCT and raised serious concerns about the risk of increased complications. Thus, considering this "blood transfusion anemia paradox", the optimal hemoglobin level to trigger RBCT in brain-injured patients has not been defined yet; also, there is insufficient evidence to provide strong recommendations regarding which hemoglobin level to target and which associated transfusion strategy (restrictive versus liberal) to select in this patient population. We summarize in this review article the more relevant studies evaluating the effects of anemia and RBCT in patients with an acute neurological condition; also, we propose some potential strategies to optimize transfusion management in such patients.

Anemia and Blood Transfusion in Patients with Isolated Traumatic Brain Injury

Rationale. By reducing cerebral oxygen delivery, anemia may aggravate traumatic brain injury (TBI) secondary insult. This study evaluated the impact of anemia and blood transfusion on TBI outcomes. Methods. This was a retrospective cohort study of adult patients with isolated TBI at a tertiary-care intensive care unit from 1/1/2000 to 31/12/2011. Daily hemoglobin level and packed red blood cell (PRBC) transfusion were recorded. Patients with hemoglobin < 10 g/dL during ICU stay (anemic group) were compared with other patients. Results. Anemia was present on admission in two (2%) patients and developed in 48% during the first week with hemoglobin < 7 g/dL occurring in 3.0%. Anemic patients had higher admission Injury Severity Score and underwent more craniotomy (50% versus 13%, p < 0.001). Forty percent of them received PRBC transfusion (2.8 ± 1.5 units per patient, median pretransfusion hemoglobin = 8.8 g/dL). Higher hospital mortality was associated with anemia (25% versus 6% for nonanemic patients, p = 0.01) and PRBC transfusion (38% versus 9% for nontransfused patients, p = 0.003). On multivariate analysis, only PRBC transfusion independently predicted hospital mortality (odds ratio: 6.8; 95% confidence interval: 1.1–42.3). Conclusions. Anemia occurred frequently after isolated TBI, but only PRBC transfusion independently predicted mortality.

Blood transfusion practices in neuroanaesthesia

Neuroanaesthesia practice is associated with risk of significant blood loss resulting in anaemia in the intraoperative and postoperative period. The transfusion triggers in a neurologically injured brain are not clearly defined. Both a low haematocrit and a high haematocrit have not shown any improvement in the outcome. Transfusion of red blood cells may improve the cerebral oxygenation on neurophysiological monitors. However, these benefits have not been translated into clinical practice. Transfusion in subarachnoid haemorrhage leads to increased incidence of vasospasm and a poor outcome. Restrictive transfusion strategy is seen to have a lower incidence of pneumonia, urinary tract infection, bacteremia and septic shock in severe head injury. Current evidence suggests that a haemoglobin (Hb) level of <7 g/dl may be deleterious to the neurosurgical population. Target Hb of 8-9 g/dl may be desirable intraoperatively. Different transfusion triggers may hold true for different neurosurgical pathologies.

Iron Deficiency Anemia Prevalence at First Stroke or Transient Ischemic Attack

Background:

Iron deficiency anemia (IDA) has been implicated in the etiology of transient ischemic attack and ischemic stroke. This study aimed to: 1) document IDA prevalence in patients ≥ 65 years of age admitted to hospital with transient ischemic attack or first ischemic stroke, and 2) investigate dietary intake as a predictor of iron status.

Methods:

Ninety-four patients were enrolled. An algorithm containing values for hemoglobin, ferritin, total iron binding capacity, transferrin saturation, and serum transferrin receptor measured at admission was used to identify IDA. Usual dietary intake was assessed with the Clue II food frequency questionnaire.

Results:

Prevalence estimates were 6.4% for IDA, 2.1% for iron deficiency without anemia, and 6.4% for anemia from other causes. IDA prevalence was significantly higher than published National Health and Nutrition Examination Survey III (NHANES III) estimates for gender-specific age groups ≥ 70 years (One-Sample Proportion Test; males p = 0.038 [n= 37]; females p = 0.002 [n=44]). A comparison of IDA prevalence against selected controls from the NHANES III database yielded an odds ratio (OR) of 6.3, 95% confidence interval (CI) 0.8 to 53.7, which was not statistically significant (Fisher's Exact Test; n=94; p = 0.118). Multivariate linear regression analysis of dietary intake with indicators of iron status (n=58) revealed only iron supplements (p = 0.013) and heme iron intake (p = 0.038) as negative predictors of total iron binding capacity (p<0.05).

Conclusions:

These findings support the initiation of a prospective case control study to investigate IDA as a risk factor for ischemic stroke in elderly patients.

Preoperative anemia increases postoperative morbidity in elective cranial neurosurgery

Background:

Preoperative anemia may affect postoperative mortality and morbidity following elective cranial operations.

Methods:

The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database was used to identify elective cranial neurosurgical cases (2006-2012). Morbidity was defined as wound infection, systemic infection, cardiac, respiratory, renal, neurologic, and thromboembolic events, and unplanned returns to the operating room. For 30-day postoperative mortality and morbidity, adjusted odds ratios (ORs) were estimated with multivariable logistic regression.

Results:

Of 8015 patients who underwent elective cranial neurosurgery, 1710 patients (21.4%) were anemic. Anemic patients had an increased 30-day mortality of 4.1% versus 1.3% in non-anemic patients (P < 0.001) and an increased 30-day morbidity rate of 25.9% versus 14.14% in non-anemic patients (P < 0.001). The 30-day morbidity rates for all patients undergoing cranial procedures were stratified by diagnosis: 26.5% aneurysm, 24.7% sellar tumor, 19.7% extra-axial tumor, 14.8% intra-axial tumor, 14.4% arteriovenous malformation, and 5.6% pain. Following multivariable regression, the 30-day mortality in anemic patients was threefold higher than in non-anemic patients (4.1% vs 1.3%; OR = 2.77; 95% CI: 1.65-4.66). The odds of postoperative morbidity in anemic patients were significantly higher than in non-anemic patients (OR = 1.29; 95% CI: 1.03-1.61). There was a significant difference in postoperative morbidity event odds with a hematocrit level above (OR = 1.07; 95% CI: 0.78-1.48) and below (OR = 2.30; 95% CI: 1.55-3.42) 33% [hemoglobin (Hgb) 11 g/dl].

Conclusions:

Preoperative anemia in elective cranial neurosurgery was independently associated with an increased risk of 30-day postoperative mortality and morbidity when compared to non-anemic patients. A hematocrit level below 33% (Hgb 11 g/dl) was associated with a significant increase in postoperative morbidity.

Blood use in neurosurgical cases at the university hospital of the west indies

OBJECTIVE

Many neurosurgical cases are done without the need for blood transfusion, yet blood is unnecessarily cross-matched, resulting in wasted resources. This study was undertaken to document and compare the number of units of blood components requested, cross-matched and transfused in neurosurgical cases at the University Hospital of the West Indies (UHWI).

METHODS

A prospective, observational study was undertaken over one year. Data collected for each patient included demographic information, relevant perioperative data, and blood banking data including blood components requested, cross-matched and transfused. Data were analysed using SPSS version 16.

RESULTS

Data were analysed on 152 patients, 71 females (46.7%) and 81 males (53.3%). The mean age was 48.7 ± 19.6 years and 100 of the procedures were done electively (65.8%). Blood components were ordered in 114 (75%) cases, red cells more commonly in 113 (74.3%) patients, and plasma in 19 (12.5%) patients. Overall, 20 patients (13.2%) were transfused. Most patients (90.9%) needed one to two units of blood. Of the 236 units of blood components that were cross-matched or prepared, only 62 were transfused. The cross-match/preparation to transfusion ratio (CTR/PTR) was 6.00 for red cells and 1.31 for plasma. Preoperative haemoglobin ≤ 10.0 g/dL (p = 0.001), estimated blood loss of ≥ 1 litre (p < 0.001), higher American Society of Anesthesiologists (ASA) physical status score (p < 0.03) and a resident as lead surgeon (p < 0.05), were significant predictors of blood transfusion.

CONCLUSION

The transfusion rate was low with a high cross-match to transfusion ratio, suggesting that less cross-matching is needed. A new approach to blood ordering for neurosurgical cases is recommended.

Impact of preoperative anemia on outcomes in patients undergoing elective cranial surgery

Object

The objective of this study was to assess whether preoperative anemia in patients undergoing elective cranial surgery influences outcomes in the immediate perioperative period (≤ 30 days).

Methods

The National Surgical Quality Improvement Program (NSQIP) was used to identify 6576 patients undergoing elective cranial surgery between 2006 and 2011. Propensity scores were used to match patients with moderate to severe anemia (moderate-severe) or mild anemia with patients without anemia. Logistic regression analysis was used to predict the outcomes of interest. Sensitivity analyses were used to limit the sample to patients without perioperative transfusion as well as those who underwent craniotomy for definitive resection of a malignant brain tumor.

Results

A total of 6576 patients underwent elective cranial surgery, of whom 175 had moderate-severe anemia and 1868 had mild anemia. Patients with moderate-severe (odds ratio 1.8, 95% CI 1.1–2.8) and mild (odds ratio 1.5, 95% CI 1.3–1.7) anemia were more likely to have prolonged length of stay (LOS) in the hospital compared to those with no anemia. Similarly, in patients who underwent craniotomy for a malignant tumor resection (n = 2537), anemia of any severity was associated with prolonged LOS, but not postoperative complications nor death.

Conclusions

Anemia is not associated with an overall increased risk for adverse outcomes in patients undergoing elective cranial surgery. However, patients with anemia are more likely to experience prolonged hospitalization postoperatively, resulting in increased resource utilization.

Postoperative stroke related to cardiac surgery in octogenarians

OBJECTIVES

Demographics of cardiac surgery patients are changing, with an increase in aged patients. We aim to identify risk factors, mortality, morbidity and increasing postoperative costs due to postoperative stroke in octogenarians following cardiopulmonary bypass (CPB).

METHODS

A total of 418 consecutive patients older than 80 years (Group A) who underwent cardiac surgery with CPB between 2000 and 2012 were matched according to gender, surgical procedure and comorbidities with 426 younger patients (Group B). Risk factors for postoperative stroke were retrospectively evaluated.

RESULTS

We identified postoperative stroke in 4.1% of patients in Group A and in 3.5% in Group B (P = 0.65). Early stroke was diagnosed in 13 patients in Group A (76.5%) and 10 patients in Group B (66.7%) (P = 0.53). In multivariate analysis, preoperative anaemia (P = 0.033; odds ratio [OR]: 3.84; 95% CI: 1.11-13.28) was the only risk factor associated with postoperative stroke in Group A. In Group B, preoperative peripheral vascular disease (P = 0.0003; OR: 7.30; 95% CI: 2.47-21.55) and postoperative atrial fibrillation (P = 0.0134; OR: 4.05; 95% CI: 1.33-12.31) were identified as risk factors.

CONCLUSIONS

Incidence of postoperative stroke after CPB was not significantly higher in our octogenarian population. Although in younger patients peripheral vascular disease and cardiac rhythm disturbances were significant risk factors, it seems that factors related to intraoperative brain oxygenation (secondary to preoperative anaemia) are the most critical determinant of stroke in the elderly.

The relationship between low intraoperative hematocrit levels during cardiopulmonary bypass and postoperative neurological events

OBJECTIVE

The objective of our study is to analyze whether low intraoperative hematocrit levels have an effect upon postoperative neurological events.

METHODS

Our study included 140 patients who underwent isolated coronary bypass under cardiopulmonary bypass between 2009 and 2012. The main group of the study was 70 patients with intraoperative hematocrit levels lower than 22%. These patients' 30-day postoperative neurological (particularly stroke) follow up was registered as the main data of the study. Another group of 70 patients possessing the same demographic features who underwent open heart surgery with hematocrit levels remaining above 22% were registered as the control group for perioperative neurological data.

RESULTS

The average age of the patients with hematocrit levels below and above 22% was 56.8 ± 5.8 years and 54.1 ± 7.3 years, respectively. The mean follow-up period of the patients was 37.2 ± 8.6 days. None of the patients had any neurological postoperative sequalae. No mortalities occurred. One patient who had mild paresthesia and motor weakness of the left hand had no pathological finding on computed tomography and was diagnosed with peripheral neuropathy due to intraoperative sternal retraction.

CONCLUSION

Because our study revealed no cerebrovascular events, coronary bypass surgery under cardiopulmonary bypass may be safely conducted even in patients with hematocrit levels lower than 22%.

Selective β1-Antagonism with Bisoprolol Is Associated with Fewer Postoperative Strokes than Atenolol or Metoprolol

Background:

Perioperative metoprolol increases postoperative stroke. Animal studies indicate that the mechanism may be related to attenuated β2-adrenoreceptor-mediated cerebral vasodilatation. The authors therefore conducted a cohort to study whether the highly β1-specific β-blocker (bisoprolol) was associated with a reduced risk of postoperative stroke compared with less selective β-blockers (metoprolol or atenolol).

Methods:

The authors conducted a single-center study on 44,092 consecutive patients with age 50 yr or more having noncardiac, nonneurologic surgery. The primary outcome was stroke within 7 days of surgery. The secondary outcome was a composite of all-cause mortality, postoperative myocardial injury, and stroke. A propensity score-matched cohort was created to assess the independent association between bisoprolol and less β1-selective agents metoprolol or atenolol. A secondary analysis using logistic regression, based on previously identified confounders, also compared selective β1-antagonism.

Results:

Twenty-four percent (10,756) of patients were exposed to in-hospital β-blockers. A total of 88 patients (0.2%) suffered a stroke within 7 days of surgery. The matched cohort consisted of 2,462 patients, and the pairs were well matched for all variables. Bisoprolol was associated with fewer postoperative strokes than the less selective agents (odds ratio = 0.20; 95% CI, 0.04–0.91). Multivariable risk-adjustment in the β-blockers-exposed patients comparing bisoprolol with the less selective agents was associated with a similarly reduced stroke rate.

Conclusions:

The use of metoprolol and atenolol is associated with increased risks of postoperative stroke, compared with bisoprolol. These findings warrant confirmation in a pragmatic randomized trial.

Blood transfusion in sickle cell disease leading to posterior reversible encephalopathy syndrome (PRES)

Children with sickle cell disease have a very high risk of lifelong neurologic morbidity and mortality. Cerebrovascular accidents are a known complication in children with sickle cell disease. Posterior reversible encephalopathy syndrome is a constellation of acute neurologic findings increasingly recognized in pediatric critical care population with evidence of vasogenic edema on brain imaging possibly due to cerebral vascular endothelial cell dysfunction. This report, for the first time, describes a young adult with sickle cell disease who developed posterior reversible encephalopathy syndrome following blood transfusion.

Impact of erythropoietin on intensive care unit patients

Anemia is common in intensive care unit (ICU) patients. Red blood cell (RBC) transfusions are mainstays of their treatment and can be life-saving. Allogeneic blood components inherently bear risks of infection and immune reactions. Although these risks are rare in developed countries, recombinant human erythropoietin (rhEpo) and other erythropoiesis-stimulating agents (ESAs) have been considered alternative anti-anemia treatment options. As summarized herein, however, most of the clinical studies suggest that ESAs are not usually advisable in ICU patients unless approved indications exist (e.g., renal disease). First, ESAs act in a delayed way, inducing an increase in reticulocytes only after a lag of 3-4 days. Second, many critically ill patients present with ESA resistance as inflammatory mediators impair erythropoietic cell proliferation and iron availability. Third, the ESA doses used for treatment of ICU patients are very high. Fourth, ESAs are not legally approved for general use in ICU patients. Solely in distinct cases, such as Jehovah's Witnesses who refuse allogeneic blood transfusions due to religious beliefs, ESAs may be considered an exceptional therapy.

Perioperative management of traumatic brain injury

Traumatic brain injury (TBI) is a major public health problem and the leading cause of death and disability worldwide. Despite the modern diagnosis and treatment, the prognosis for patients with TBI remains poor. While severity of primary injury is the major factor determining the outcomes, the secondary injury caused by physiological insults such as hypotension, hypoxemia, hypercarbia, hypocarbia, hyperglycemia and hypoglycemia, etc. that develop over time after the onset of the initial injury, causes further damage to brain tissue, worsening the outcome in TBI. Perioperative period may be particularly important in the course of TBI management. While surgery and anesthesia may predispose the patients to new onset secondary injuries which may contribute adversely to outcomes, the perioperative period is also an opportunity to detect and correct the undiagnosed pre-existing secondary insults, to prevent against new secondary insults and is a potential window to initiate interventions that may improve outcome of TBI. For this review, extensive Pubmed and Medline search on various aspects of perioperative management of TBI was performed, followed by review of research focusing on intraoperative and perioperative period. While the research focusing specifically on the intraoperative and immediate perioperative TBI management is limited, clinical management continues to be based largely on physiological optimization and recommendations of Brain Trauma Foundation guidelines. This review is focused on the perioperative management of TBI, with particular emphasis on recent developments.

Cerebral thrombosis in patients with β-thalassemia: a systematic review

A hypercoagulable state has been documented in patients with β-thalassemia. It could result in thromboembolic events in several organs including brain involvement, which deserves particular attention. We summarized the prevalence of cerebral involvement in patients with β-thalassemia worldwide. We conducted an electronic search on PUBMED (MEDLINE), SCOPUS, and Google Scholar databases up to January 2011. Overall 152 thalassemic patients with cerebral thromboembolic events and a proportion of 1.13% (134 of 11770) were recorded. From all patients with cerebral thromboembolic events, 74 (48%) were splenectomized. Cerebral thromboembolic events were reported after transfusion in six β-thalassemia major, and two β-thalassemia intermedia patients. Three β-thalassemia major patients had irregular transfusion and 22 β-thalassemia intermedia patients were not transfused. Thrombocytosis were determined in 11 β-thalassemia major, and 15 β-thalassemia intermedia patients. Cardiomyopathy was present in 13 β-thalassemia major and four β-thalassemia intermedia patients. Also, nine β-thalassemia major patients had diabetes. Activated protein C resistant, decreased protein C or protein S or plasminogen level was detected in eight β-thalassemia major patients. Cerebral involvement appears to be associated with increasing age, transfusion naivety, splenectomy, thrombocytosis, intensive transfusion, decreased protein C level, and having risk factors for cerebrovascular accident such as cardiomyopathy, and diabetes. In light of these findings, diagnostic MRI is recommended in high-risk groups to screen for early asymptomatic brain damage. If brain ischemia is found, the administration of antiplatelet aggregants or blood transfusion is likely to be beneficial. In addition, in thalassemic patients who complicated with a thromboembolic event, secondary prophylaxis could be helpful to prevent cerebral thromboembolic events.

Is methemoglobin an inert bystander, biomarker or a mediator of oxidative stress--The example of anemia?

Acute anemia increases the risk for perioperative morbidity and mortality in critically ill patients who experience blood loss and fluid resuscitation (hemodilution). Animal models of acute anemia suggest that neuronal nitric oxide synthase (nNOS)-derived nitric oxide (NO) is adaptive and protects against anemia-induced mortality. During acute anemia, we have observed a small but consistent increase in methemoglobin (MetHb) levels that is inversely proportional to the acute reduction in Hb observed during hemodilution in animals and humans. We hypothesize that this increase in MetHb may be a biomarker of anemia-induced tissue hypoxia. The increase in MetHb may occur by at least two mechanisms: (1) direct hemoglobin oxidation by increased nNOS-derived NO within the perivascular tissue and (2) by increased deoxyhemoglobin (DeoxyHb) nitrite reductase activity within the vascular compartment. Both mechanisms reflect a potential increase in NO signaling from the tissue and vascular compartments during anemia. These responses are thought to be adaptive; as deletion of nNOS results in increased mortality in a model of acute anemia. Finally, it is possible that prolonged activation of these mechanisms may lead to maladaptive changes in redox signaling. We hypothesize, increased MetHb in the vascular compartment during acute anemia may reflect activation of adaptive mechanisms which augment NO signaling. Understanding the link between anemia, MetHb and its treatments (transfusion of stored blood) may help us to develop novel treatment strategies to reduce the risk of anemia-induced morbidity and mortality.

Protecting the brain during neurosurgical procedures: strategies that can work

PURPOSE OF REVIEW

The quest for neuroprotection strategies during periods of neuronal vulnerability persists despite decades of basic and clinical research. This review will focus on the latest developments in the area of clinical brain protection with the major emphasis on strategies that can be beneficial during neurosurgical procedures.

RECENT FINDINGS

Brain protection in neurosurgical patients may be achieved by nonpharmacological and pharmacological strategies. Pharmacological neuroprotection including anaesthetic administration have not been recently shown to be successful. Alternatively, nonpharmacological strategies including maintenance of cerebral perfusion by adequate control of mean arterial pressure (≥80 mmHg), liberal normoglycaemia (7.8-10 mmol/l), adequate haemoglobin levels (preoperative ≥120 g/l and intraoperative ≥90 g/l) and induction of hypertension (20-40% of preoperative values) in certain neurosurgical situations can be beneficial as neuroprotectants during neurosurgery. Mild hypothermia (32-35°C) failed to achieve neuroprotective effects in several situations of brain injury.

SUMMARY

The findings of this review suggest that the anaesthesiologist is compelled to use nonpharmacological strategies sometimes based on empiric evidence to protect the brain during neurosurgical procedures. These strategies are simple, have high benefit/risk ratios and are inexpensive. Rigorous controlled clinical studies are needed to investigate the neuroprotective efficacy of these commonly used nonpharmacological methods.

Red blood cell transfusion in neurosurgery

BACKGROUND

The necessity of red blood cell (RBC) transfusions in neurosurgical procedures is under debate. Although detailed recommendations exist for many other surgical disciplines, there are very limited data on the probability of transfusions during neurosurgical procedures.

METHODS

Three-thousand and twenty-six consecutive adult patients undergoing neurosurgical procedures at Saarland University Hospital from December 2006 to June 2008 were retrospectively analyzed for administration of RBCs. The patients were grouped into 11 main diagnostic categories for analysis. The transfusion probability and cross-match to transfusion ratio (C/T ratio) were calculated.

RESULTS

Overall, the transfusion probability for neurosurgical procedures was 1.7 % (52/3,026). The probability was 6.5 % for acute subdural hematoma (7/108), 6.2 % for spinal tumors (5/80), 4.6 % for intracerebral hemorrhage (ICH, 4/98), 2.8 % for abscess (3/108), 2.4 % for traumatic brain injury (4/162), 2.3 % for cerebral ischemia (1/44), 1.9 % for subarachnoid hemorrhage (SAH) /aneurysms (4/206), 1.4 % for brain tumors (10/718), 0.8 % for hydrocephalus (2/196), 0.4 % for degenerative diseases of the spine (5/1290), including 3.6 % (3/82) for posterior lumbar interbody fusion (PLIF) and 0 % for epidural hematoma (0/15). The transfusion probabilities for clipping and coiling of SAH were 2.9 % (2/68) and 1.7 % (2/120) respectively.

CONCLUSIONS

The probability of blood transfusion during neurosurgical procedures is well below the 10 % level which is generally defined as the limit for preoperative appropriation of RBCs. Patients with spinal tumors, acute subdural hematomas or ICH, i.e., patients undergoing large decompressive procedures of bone or soft tissue, had a higher probability of transfusion.

Perioperative management of adult traumatic brain injury

This article presents an overview of the management of traumatic brain injury (TBI) as relevant to the practicing anesthesiologist. Key concepts surrounding the pathophysiology and anesthetic principles are used to describe potential ways to reduce secondary insults and improve outcomes after TBI.

Red Blood Cell Transfusion and Transfusion Alternatives in Traumatic Brain Injury

OPINION STATEMENT: Anemia develops in about 50% of patients hospitalized with traumatic brain injury (TBI) and is recognized as a cause of secondary brain injury. This review examines the effects of anemia and transfusion on TBI patients through a literature search to identify original research on anemia and transfusion in TBI, the effects of transfusion on brain physiology, and the role of erythropoietin or hemoglobin-based blood substitutes (HBBSs). However, the amount of high-quality, prospective data available to help make decisions about when TBI patients should be transfused is very small. Randomized transfusion trials have involved far too few TBI patients to reach definitive conclusions. Thus, it is hardly surprising that there is widespread practice variation. In our opinion, a hemoglobin transfusion threshold of 7 g/dL cannot yet be considered safe for TBI patients admitted to hospital, and in particular to the ICU, as it is for other critically ill patients. Red blood cell transfusions often have immediate, seemingly beneficial effects on cerebral physiology, but the magnitude of this effect may depend in part upon how long the cells have been stored before administration. In light of existing physiological data, we generally aim to keep hemoglobin concentrations greater than 9 g/dL during the first several days after TBI. In part, the decision is based on the patient's risk of or development of secondary ischemia or brain injury. An increasing number of centers use multimodal neurologic monitoring, which may help to individualize transfusion goals based on the degree of cerebral hypoxia or metabolic distress. When available, brain tissue oxygen tension values less than 15-20 mm Hg or a lactate:pyruvate ratio greater than 30-40 would influence us to use more aggressive hemoglobin correction (e.g., a transfusion threshold of 10 g/dL). Clinicians can attempt to reduce transfusion requirements by limiting phlebotomy, minimizing hemodilution, and providing appropriate prophylaxis against gastrointestinal hemorrhage. Administration of exogenous erythropoietin may have a small impact in further reducing the need for transfusion, but it also may increase complications, most notably deep venous thrombosis. Erythropoietin is currently of great interest as a potential neuroprotective agent, but until it is adequately evaluated in randomized controlled trials, it should not be used routinely for this purpose. HBBSs are also of interest, but existing preparations have not been shown to be beneficial-or even safe-in the context of TBI.

Effects of hemodilution after traumatic brain injury in juvenile rats

BACKGROUND

Normovolemic hemodilution (HD) in adult animal studies has shown exacerbation of traumatic brain injury (TBI) lesion volumes. Similar studies in juvenile rats have not been reported and outcomes are likely to be different. This study investigated the effects of normovolemic hemodilution (21% hematocrit) in a juvenile TBI (jTBI) model.

METHODS

Twenty 17-day-old rats underwent moderate cortical contusion impact injury (CCI) and were divided into four groups: CCI/hemodilution (HD) (group HD), CCI/no HD (group C), Sham/HD (group SHD), and Sham/no HD (group S). Regional laser Doppler flowmetry (LDF), edema formation (MRI-T2WI), water mobility assessed using diffusion weighted imaging (MRI-DWI), open field activity tests, and histological analyses were evaluated for lesion characteristics.

RESULTS

Hemodilution significantly increased blood flow in the HD compared to the C group after TBI. T2WI revealed a significantly increased extravascular blood volume in HD at 1, 7, and 14 days post-CCI. Edematous tissue and total contusional lesion volume were higher in HD-treated animals at 1 and 14 days. DWI revealed that HD, SHD, and C groups had elevated water mobility compared to S groups in the ipsilateral cortex and striatum. Histology showed a larger cortical lesion in the C than HD group. Open field activity was increased in HD, C, and SHD groups compared to the S group.

CONCLUSIONS

Hemodilution results in significant brain hyperemia with increased edema formation, extravascular blood volume, and water mobility after jTBI. Hemodilution results in less cortical damage but did not alter behavior. Hemodilution is likely not to be clinically beneficial following jTBI.

Relationship between the hemoglobin level at hospital arrival and post-cardiac arrest neurologic outcome

BACKGROUND

The hemoglobin (Hb) level is an essential determinant of oxygen delivery. The restoration of blood perfusion to vital organs and the capacity for oxygen delivery may be associated with ischemia and reperfusion injuries during cardiac arrest and after cardiac arrest. However, whether the Hb level is associated with neurologic outcome in post-cardiac arrest patients remains unclear.

METHODS

Emergency medical service information and clinical demographics were compiled for witnessed out-of-hospital cardiac arrest patients with coma after the restoration of spontaneous circulation. The study end point was defined as a favorable neurologic outcome at 28 days. We evaluated the relationship between the Hb level at the time of hospital arrival and the neurologic outcome using univariate analyses and a multivariate logistic regression analysis.

RESULTS

There were 137 witnessed cardiac arrest patients: 49 (35.7%) survived and 34 (24.8%) achieved a favorable neurologic outcome. Univariate analyses showed that the favorable outcome group was characterized as having a higher Hb level, a younger age, a higher percentage of male patients, and ventricular fibrillation as the initial cardiac rhythm. In a multivariate analysis adjusting for potential confounding factors, the Hb level at the time of hospital arrival (odds ratio, 1.26; 95% confidence interval, 1.00-1.58) was an independent predictor of a favorable neurologic outcome.

CONCLUSION

A higher Hb level at the time of hospital arrival was associated with a favorable short-term neurologic outcome among post-cardiac arrest patients with a presumed cardiac etiology.