Anemia is associated with metabolic distress and brain tissue hypoxia after subarachnoid hemorrhage

Low hemoglobin causes hematoma expansion and poor intracerebral hemorrhage outcomes

Objectives

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

Methods

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

Results

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

Conclusions

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

Predicting postacute phase anaemia after aneurysmal subarachnoid haemorrhage: nomogram development and validation

BACKGROUND

Anaemia is a severe and common complication in patients with aneurysmal subarachnoid haemorrhage (aSAH). Early intervention for at-risk patients before anaemia occurs is indicated as potentially beneficial, but no validated method synthesises patients' complicated clinical features into an instrument. The purpose of the current study was to develop and externally validate a nomogram that predicted postacute phase anaemia after aSAH.

METHODS

We developed a novel nomogram for aSAH patients to predict postacute phase anaemia (3 days after occurrence of aSAH, prior to discharge) on the basis of demographic information, imaging, type of treatment, aneurysm features, blood tests and clinical characteristics. We designed the model from a development cohort and tested the nomogram in external and prospective validation cohorts. We included 456 aSAH patients from The First Affiliated Hospital for the development, 220 from Sanmen People's Hospital for external validation and a prospective validation cohort that included 13 patients from Hangzhou Red Cross Hospital. We assessed the performance of the nomogram via concordance statistics and evaluated the calibration of predicted anaemia outcome with observed anaemia occurrence.

RESULTS

Variables included in the nomogram were age, treatment method (open surgery or endovascular therapy), baseline haemoglobin level, fasting blood glucose level, systemic inflammatory response syndrome score on admission, Glasgow Coma Scale score, aneurysm size, prothrombin time and heart rate. In the validation cohort, the model for prediction of postacute phase anaemia had a c-statistic of 0.910, with satisfactory calibration (judged by eye) for the predicted and reported anaemia outcome. Among forward-looking forecasts, our predictive model achieved an 84% success rate, which showed that it has some clinical practicability.

CONCLUSIONS

The developed and validated nomogram can be used to calculate individualised anaemia risk and has the potential to serve as a practical tool for clinicians in devising improved treatment strategies for aSAH.

Anemia From Inflammation After Intracerebral Hemorrhage and Relationships With Outcome

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

REGISTRATION

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

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

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

Relationships of Hematocrit With Chronic Covert and Acute Symptomatic Lacunar Ischemic Lesions

BACKGROUND AND OBJECTIVES

Red blood cell (RBC) concentrations are known to associate with ischemic stroke. It is unclear whether RBC concentrations associate specifically with small vessel disease lacunar infarcts. We investigated the hypothesis that RBC concentrations associate with both chronic covert and acute symptomatic brain MRI lacunar infarcts.

METHODS

A cross-sectional observational analysis was performed across 2 cohorts with available hematocrit (as the assessment of RBC concentration exposure) and MRI outcome data. The primary setting was a population-based cohort of stroke-free, older adult (>50 years) participants from the Northern Manhattan Study (NOMAS) enrolled between 2003 and 2009. A second replication sample consisted of patients admitted with acute stroke and enrolled into the Columbia Stroke Registry (CSR) between 2005 and 2020. Associations of hematocrit with (1) chronic, covert lacunar infarcts and (2) symptomatic (i.e., acute) lacunar strokes were separately assessed from the NOMAS and CSR cohorts, respectively, using general additive models after adjusting for relevant covariates.

RESULTS

Of 1,218 NOMAS participants analyzed, 6% had chronic, covert lacunar infarcts. The association between hematocrit and these covert lacunar infarcts was U-shaped (χ2 = 9.21 for nonlinear associations; p = 0.03), with people with hematocrit extremes being more likely to have covert lacunar infarcts. Of the 1,489 CSR patients analyzed, 23% had acute lacunar strokes. In this sample, only the relationships of increased hematocrit concentrations and lacunar strokes were replicated (adjusted coefficient β = 0.020; SE = 0.009; p = 0.03).

DISCUSSION

We identified relationships of hematocrit with MRI lacunar infarcts in both stroke-free and ischemic stroke cohorts, respectively. The relationship between increased hematocrit concentrations with lacunar infarcts was replicated in both cohorts. Further studies are required to clarify the mechanisms behind the relationships of hematocrit with ischemic cerebral small vessel disease.

Anemia and Red Blood Cell Transfusion in Aneurysmal Subarachnoid Hemorrhage

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

Relationships of Hemoglobin Concentration, Ischemic Lesions, and Clinical Outcomes in Patients With Intracerebral Hemorrhage

BACKGROUND

Hemoglobin concentration and diffusion-weighted imaging (DWI) ischemic lesions are separately known to be associated with poor intracerebral hemorrhage (ICH) outcomes. While hemoglobin concentrations have known relationships with ischemic stroke, it is unclear whether hemoglobin concentration is associated with DWI ischemic lesions after ICH. We sought to investigate the hypothesis that hemoglobin concentrations would associate with DWI lesions after ICH and further investigated their relationships with clinical outcomes.

METHODS

Supratentorial ICH patients enrolled between 2010 and 2016 to a prospective, multicenter, observational cohort study (ERICH study [Ethnic/Racial Variations of Intracerebral Hemorrhage]) were assessed. Patients from this study with baseline, admission hemoglobin, and hospitalization magnetic resonance imaging were analyzed. Hemoglobin was examined as the primary exposure variable defined as a continuous variable (g/dL). Magnetic resonance imaging DWI ischemic lesion presence was assessed as the primary radiographic outcome. Primary analyses assessed relationships of hemoglobin with DWI lesions. Secondary analyses assessed relationships of DWI lesions with poor 3-month outcomes (modified Rankin Scale score, 4-6). These analyses were performed using separate multivariable logistic regression models adjusting for relevant covariates.

RESULTS

Of 917 patients with ICH analyzed, mean baseline hemoglobin was 13.8 g/dL (±1.9), 60% were deep ICH, and DWI lesions were identified in 27% of the cohort. In our primary analyses, increased hemoglobin, defined as a continuous variable, was associated with DWI lesions (adjusted odds ratio, 1.21 per 1 g/dL change in hemoglobin [95% CI, 1.07-1.37]) after adjusting for sex, race, ICH severity, time to magnetic resonance imaging, and acute blood pressure change. In secondary analyses, DWI lesions were associated with poor 3-month outcomes (adjusted odds ratio, 1.83 [95% CI, 1.24-2.69]) after adjusting for similar covariates.

CONCLUSIONS

We identified novel relationships between higher baseline hemoglobin concentrations and DWI ischemic lesions in patients with ICH. Further studies are required to clarify the role of hemoglobin concentration on both cerebral small vessel disease pathophysiology and ICH outcomes.

Fine tuning of neurointensive care in aneurysmal subarachnoid hemorrhage: From one-size-fits-all towards individualized care

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe type of acute brain injury with high mortality and burden of neurological sequelae. General management aims at early aneurysm occlusion to prevent re-bleeding, cerebrospinal fluid drainage in case of increased intracranial pressure and/or acute hydrocephalus, and cerebral blood flow augmentation in case of delayed ischemic neurological deficits. In addition, the brain is vulnerable to physiological insults in the acute phase and neurointensive care (NIC) is important to optimize the cerebral physiology to avoid secondary brain injury. NIC has led to significantly better neurological recovery following aSAH, but there is still great room for further improvements. First, current aSAH NIC management protocols are to some extent extrapolated from those in traumatic brain injury, notwithstanding important disease-specific differences. Second, the same NIC management protocols are applied to all aSAH patients, despite great patient heterogeneity. Third, the main variables of interest, intracranial pressure and cerebral perfusion pressure, may be too superficial to fully detect and treat several important pathomechanisms. Fourth, there is a lack of understanding not only regarding physiological, but also cellular and molecular pathomechanisms and there is a need to better monitor and treat these processes. This narrative review aims to discuss current state-of-the-art NIC of aSAH, knowledge gaps in the field, and future directions towards a more individualized care in the future.

Association of hemoglobin trend and outcomes in aneurysmal subarachnoid hemorrhage: A single center cohort study

BACKGROUND

Anemia has been linked to delayed cerebral ischemia (DCI) and worse outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). However, the association of hemoglobin (Hb) trend and outcomes is not well studied. We investigated predictors of Hb trend and its association with outcomes in patients with aSAH. Our hypothesis was that a negative Hb trend is associated with poorer outcomes independent of Hb values.

METHODS

We conducted a retrospective study of a prospectively collected cohort of consecutive patients with aSAH who were admitted to an academic center (2016-2021). We tested the association of Hb trend and values with measures including DCI and poor functional outcome defined as modified Rankin scale 4-6 at 3 months after discharge. Multiple linear regression analysis was used to identify factors associated with Hb difference from admission to discharge.

RESULTS

We included 310 patients with confirmed aneurysmal etiology (mean age 57 years, SD13.6; 62 % female). Greater Hb decrement from admission to discharge was independently associated with higher likelihood of both DCI (OR 1.28 per 1 g/dl decrease in Hb, 95 % CI 1.08-1.47; p = 0.003) and poor functional outcome (OR 1.27 per 1 g/dl decrease in Hb, 1.03-1.53; p = 0.026) independent of any absolute Hb values. Predictors of Hb decrement from admission to discharge were hospital length of stay, Hunt and Hess grades, female sex and age.

CONCLUSION

Greater Hb decrement can be associated with higher likelihood of DCI and poor functional outcome in aSAH. More evidence is needed to use Hb trend to guide transfusion threshold in aSAH patients.

Systematic review and meta-analysis of outcome-relevant anemia in patients with subarachnoid hemorrhage

Anemia is a common, treatable condition in patients with aneurysmal subarachnoid hemorrhage (SAH) and has been associated with poor outcome. As there are still no guidelines for anemia management after aneurysm rupture, we aimed to identify outcome-relevant severity of anemia in SAH. We systematically searched PubMed, Embase, Scopus, Web of Science, and Cochrane Library for publications before Oct 23rd, 2022, reporting on anemia in SAH patients. The presence and severity of anemia were assessed according to the reported hemoglobin values and/or institutional thresholds for red blood cells transfusion (RBCT). Out of 1863 original records, 40 full-text articles with a total of 14,701 patients treated between 1996 and 2020 were included in the final analysis (mean 445.48 patients per study). A substantial portion of patients developed anemia during SAH (mean pooled prevalence 40.76%, range 28.3-82.6%). RBCT was administered in a third of the cases (mean 32.07%, range 7.8-88.6%), with institutional threshold varying from 7.00 to 10.00 g/dL (mean 8.5 g/dL). Anemia at the onset of SAH showed no impact on SAH outcome. In contrast, even slight anemia (nadir hemoglobin < 11.0-11.5 g/dL) occurring during SAH was associated with the risk of cerebral infarction and poor outcome at discharge and follow-up. The strongest association with SAH outcome was observed for nadir hemoglobin values ranging between 9.0 and 10.0 g/dL. The effect of anemia on SAH mortality was marginal. The development of anemia during SAH is associated with the risk of cerebral infarction and poor outcome at discharge and follow-up. Outcome-relevant severity of post-SAH anemia begins at hemoglobin levels clearly above the thresholds commonly set for RBCT. Our findings underline the need for further studies to define the optimal management of anemia in SAH patients.

Early management of patients with aneurysmal subarachnoid hemorrhage in a hospital with neurosurgical/neuroendovascular facilities: a consensus and clinical recommendations of the Italian Society of Anesthesia and Intensive Care (SIAARTI)-part 2

BACKGROUND

Questions remain on the optimal management of subarachnoid hemorrhage (SAH) patients once they are admitted to the referring center, before and after the aneurysm treatment. To address these issues, we created a consensus of experts endorsed by the Italian Society of Anesthesia and Intensive Care (SIAARTI) to provide clinical guidance regarding this topic. Specifically, in this manuscript (part 2), we aim to provide a list of experts' recommendations regarding the management of SAH patients in a center with neurosurgical/neuroendovascular facilities after aneurysm treatment.

METHODS

A multidisciplinary consensus panel composed by 24 physicians selected for their established clinical and scientific expertise in the acute management of SAH patients with different specializations (anesthesia/intensive care, neurosurgery, and interventional neuroradiology) was created. A modified Delphi approach was adopted.

RESULTS

A total of 33 statements were discussed, voted, and approved. Consensus was reached on 30 recommendations (28 strong and 2 weak). In 3 cases, where consensus could not be agreed upon, no recommendation was provided.

CONCLUSIONS

This consensus provides practical recommendations (and not mandatory standard of practice) to support clinician's decision-making in the management of SAH patients in centers with neurosurgical/neuroendovascular facilities after aneurysm securing.

Multimodal brain monitoring following traumatic brain injury: A primer for intensive care practitioners

Traumatic brain injury (TBI) is common and potentially devastating. Traditional examination-based patient monitoring following TBI may be inadequate for frontline clinicians to reduce secondary brain injury through individualized therapy. Multimodal neurologic monitoring (MMM) offers great potential for detecting early injury and improving outcomes. By assessing cerebral oxygenation, autoregulation and metabolism, clinicians may be able to understand neurophysiology during acute brain injury, and offer therapies better suited to each patient and each stage of injury. Hence, we offer this primer on brain tissue oxygen monitoring, pressure reactivity index monitoring and cerebral microdialysis. This narrative review serves as an introductory guide to the latest clinically-relevant evidence regarding key neuromonitoring techniques.

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.

Individualized blood pressure targets in the postoperative care of patients with intracerebral hemorrhage

OBJECTIVE

Recent guidelines recommend targeting a systolic blood pressure (SBP) < 140 mm Hg in the early management of patients with spontaneous intracerebral hemorrhage (ICH). The optimal SBP targets for ICH patients after hematoma evacuation (HE) remain unclear. Here, the authors aimed to define the optimal SBP range based on multimodal neuromonitoring data.

METHODS

Forty poor-grade ICH patients who had undergone HE and then monitoring of intracerebral pressure, brain tissue oxygen tension (PbtO2), and cerebral metabolism (via cerebral microdialysis [CMD]) were prospectively included. Episodes of brain tissue hypoxia (BTH) (1-hour averaged PbtO2 < 20 mm Hg) and metabolic distress (CMD-lactate/pyruvate ratio [LPR] ≥ 40) were identified and linked to corresponding parameters of hemodynamic monitoring (SBP and cerebral perfusion pressure [CPP]). Multivariable regression analysis was performed using generalized estimating equations to identify associations between SBP levels, PbtO2, and brain metabolism.

RESULTS

The mean patient age was 60 (range 51-66) years and the median [IQR] initial ICH volume was 47 [29-60] ml. In multivariable models adjusted for Glasgow Coma Scale score, probe location, ICH volume, and age, lower SBP was independently associated with a higher risk of BTH (≤ 120 mm Hg: adjusted OR 2.9, p = 0.007; 120-130 mm Hg: adj OR 2.4, p = 0.002; 130-140 mm Hg: adj OR 1.6, p = 0.017) compared to a reference range of 140-150 mm Hg at the level of the foramen interventriculare Monroi, which corresponded to a CPP of 70-80 mm Hg and SBP levels between 150 and 160 mm Hg at the heart level. After exclusion of episodes with mitochondrial dysfunction, SBP targets < 140 mm Hg were associated with higher odds of cerebral metabolic distress (≤ 130 mm Hg: OR 2.5, p = 0.041; 130-140 mm Hg: OR 2.3, p = 0.033). Patients with a modified Rankin Scale score ≥ 5 at neurological ICU discharge more often exhibited BTH than patients with better outcomes (51% vs 10%, p = 0.003).

CONCLUSIONS

These data suggest that lower SPB and CPP levels are associated with a higher risk for BTH. Further studies are needed to evaluate whether a higher SPB target may prevent BTH and improve outcomes.

Association of anemia and transfusions with outcome after subarachnoid hemorrhage

INTRODUCTION

The benefits of correcting anemia using red blood cell transfusion (RBCT) after subarachnoid hemorrhage (SAH) are controversial. We aimed to evaluate the role of anemia and RBCT on neurological outcome after SAH using a restrictive transfusion policy.

OBJECTIVE

We reviewed our institutional database of adult patients admitted to the Department of Intensive Care (ICU) after non-traumatic SAH over a 5-year period. We recorded hemoglobin (Hb) levels daily for a maximum of 20 days, as well as the use of RBCT. Unfavorable neurological outcome (UO) was defined as a Glasgow Outcome Score of 1-3 at 3 months.

RESULTS

Among 270 eligible patients, UO was observed in 40% of them. Patients with UO had lower Hb over time and received RBCT more frequently than others (15/109, 14% vs. 6/161, 4% - p < 0.01). Pre-RBCT median Hb values were similar in UO and FO patients (6.9 [6.6-7.1] vs. 7.3 [6.3-8.1] g/dL - p = 0.21). The optimal discriminative Hb threshold for UO was 9 g/dL. In a multivariable analysis, neither anemia nor RBCT were independently associated with UO.

CONCLUSION

In this retrospective single center study using a restrictive strategy of RBCT in SAH patients was not associated with worse outcome in 3 months.

How to diagnose delayed cerebral ischaemia and symptomatic vasospasm and prevent cerebral infarction in patients with subarachnoid haemorrhage

PURPOSE OF REVIEW

Delayed cerebral ischaemia (DCI) complicates the clinical course of patients with subarachnoid haemorrhage (SAH) in 20--30% and substantially worsens outcome. In this review, we describe a multimodal diagnostic approach based on underlying mechanisms of DCI and provide treatment options with a special focus on the most recently published literature.

RECENT FINDINGS

Symptomatic vasospasm refers to clinical deterioration in the presence of vasospasm whereas DCI constitutes multiple causes. Pathophysiologic mechanisms underlying DCI range beyond large vessel vasospasm from neuroinflammation, to microthromboembolism, impaired cerebral autoregulation, cortical spreading depolarizations and many others. The current definition of DCI can be challenged by these mechanisms. We propose a pragmatic approach using a combination of clinical examination, cerebral ultrasonography, neuroimaging modalities and multimodal neuromonitoring to trigger therapeutic interventions in the presence of DCI. In addition to prophylactic nimodipine and management principles to improve oxygen delivery and decrease the brain metabolic demand, other specific interventions include permissive hypertension, intra-arterial application of calcium channel blockers and in selected patients angioplasty.

SUMMARY

The complex pathophysiology underlying DCI urges for a multimodal diagnostic approach triggering targeted interventions. Novel treatment concepts still have to be proven in large trials.

Initial Postoperative Hemoglobin Values Are Independently Associated With One-Year Mortality in Patients Undergoing Double-Lung Transplantation Requiring Intraoperative Transfusion

OBJECTIVE

To evaluate the association of postoperative hemoglobin values and mortality in patients undergoing double- lung transplantation with intraoperative transfusion.

DESIGN

Retrospective cohort study.

SETTING

University hospital.

PARTICIPANTS

Adult patients who underwent double-lung transplantation at the authors' institution, with intraoperative transfusion of packed red blood cells between 2009 and 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Intraoperative transfusion requirements and general characteristics of 554 patients were collected. A generalized additive model, controlling for postoperative hemoglobin levels, number of transfused units of packed red blood cells, perioperative change in hemoglobin levels, disease leading to lung transplantation, and postoperative extracorporeal membrane oxygenation, was created to predict one-year mortality. A postoperative hemoglobin level of 11.3 g/dL was calculated as an optimal cutoff point. The patients were stratified according to this level. The end -point was all-cause one-year mortality after double-lung transplantation, assessed using the Kaplan-Meier analysis with log-rank test. All-cause mortality of the 554 patients was 17%. Postoperatively, 171 patients (31%) were categorized as being below the cutoff point. Improved survival was observed in the group with higher postoperative hemoglobin values (p = 0.002).

CONCLUSION

Lower postoperative hemoglobin levels in double-lung transplantation recipients were associated with increased mortality during the first year after surgery. Confirmation of these findings in additional investigations could alter patient blood management for double-lung transplantation.

Protocolized Brain Oxygen Optimization in Subarachnoid Hemorrhage

BACKGROUND

Brain tissue hypoxia (P_btO₂ < 20 mmHg) is common after subarachnoid hemorrhage (SAH) and associated with poor outcome. Recent data suggest that brain oxygen optimization is feasible and reduces the time spent with P_btO₂ < 20 mmHg from 45 to 16% in patients with severe traumatic brain injury. Here, we intended to quantify the brain tissue hypoxia burden despite implementation of a protocolized treatment approach in poor-grade SAH patients and to identify the simultaneous occurrence of pathologic values potentially amenable to treatment.

METHODS

We present a bi-centric observational cohort study including 100 poor-grade SAH patients admitted to two tertiary care centers who underwent multimodal brain monitoring and were managed with a P_btO₂-targeted protocolized approach. P_btO₂ optimization (≥ 20 mmHg) included a stepwise neuro-intensive care approach, aiming to prevent low cerebral perfusion pressure (CPP), and blood hemoglobin, and to keep normocapnia, normoxemia, and normothermia. Based on routine blood gas analysis, hemoglobin, PaCO_2, and PaO₂ data were matched to 2-h averaged data of continuous CPP, P_btO₂, core temperature, and to hourly cerebral microdialysis (CMD) samples over the first 11 days.

RESULTS

Patients had a Glasgow Coma Scale of 3 (IQR 3-4) and were 58 years old (IQR 48-66). Overall incidence of brain tissue hypoxia was 25%, which was not different between both sites despite differences in the treatment approach. During brain tissue hypoxia, episodes of CPP < 70 mmHg (27%), PaCO₂ < 35 mmHg (19%), PaO₂ < 80 mmHg (14%), Hb < 9 g/dL (11%), metabolic crisis (CMD-lactate/pyruvate ratio > 40, and CMD-glucose < 0.7 mmol/L; 7%), and temperature > 38.3 °C (4%) were common.

CONCLUSIONS

Our results demonstrate that brain tissue hypoxia remains common despite implementation of a P_btO₂-targeted therapy in poor-grade SAH patients, suggesting room for further optimization.

Precision Medicine in Acute Brain Injury: A Narrative Review

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

Intranasal Insulin Treatment Attenuates Metabolic Distress and Early Brain Injury After Subarachnoid Hemorrhage in Mice

BACKGROUND

Intranasal administration of insulin to the brain bypasses the blood brain barrier (BBB) and can increase cerebral glucose uptake and prevent energy failure. Intranasal insulin treatment has shown neuroprotective effects in multiple central nervous system (CNS) lesions, but the effects of intranasal insulin on the metabolic and pathological process of subarachnoid hemorrhage (SAH) are not clear. This study is designed to explore the effects of intranasal insulin treatment on metabolic distress and early brain injury (EBI) after experimental SAH.

METHODS

SAH model was built by endovascular filament perforation method in adult male C57BL/6J mice, and then, insulin was administrated via intranasal route at 0, 24, and 48 h post-SAH. EBI was assessed according to the neurological performance, BBB damage, brain edema, neuroinflammatory reaction, and neuronal apoptosis at each time point. To evaluate metabolic conditions, microdialysis was used to continuously monitor the real-time levels of glucose, pyruvate, and lactate in interstitial fluid (ISF) in living animals. The mRNA and protein expression of glucose transporter-1 and 3 (GLUT-1 and -3) were also tested by RT-PCR and Western blot in brain after SAH.

RESULTS

Compared to vehicle, intranasal insulin treatment promoted the relative mRNA and protein levels of GLUT-1 in SAH brain (0.98 ± 0.020 vs 0.33 ± 0.016 at 24 h, 0.91 ± 0.25 vs 0.21 ± 0.013 at 48 h and 0.94 ± 0.025 vs 0.28 ± 0.015 at 72 h in mRNA/0.96 ± 0.023 vs 0.36 ± 0.015 at 24 h, 0.91 ± 0.022 vs 0.22 ± 0.011 at 48 h and 0.95 ± 0.024 vs 0.27 ± 0.014 at 72 h in protein, n = 8/Group, p < 0.001). Similar results were also observed in GLUT-3. Intranasal insulin reduced the lactate/pyruvate ratio (LPR) and increased ISF glucose level. It also improved neurological dysfunction, BBB damage, and brain edema and attenuated the levels of pro-inflammatory cytokines as well as neuronal apoptosis after SAH.

CONCLUSIONS

The intranasal insulin treatment protects brain from EBI possibly via improving metabolic distress after SAH.

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.

Delayed Ischemic Neurologic Deficit after Aneurysmal Subarachnoid Hemorrhage

Delayed ischemic neurologic deficit (DIND) is the main preventable cause of poor outcomes in aneurysmal subarachnoid hemorrhage (SAH) patients. Of 50% of survivors from a SAH, approximately 30% of patients will present clinical vasospasm (VS). The cornerstone of the DIND management comprises prevention and early identification. Several diagnostic methods have been proposed differing in efficacy, invasiveness, and costs. Serial neurological examination is the most reliable method to detect a new neurological deficit. On the other hand, comatose patients require advanced monitoring methods which identify changes in the microcirculatory environment, brain autoregulation, and spreading depolarization. Multimodality monitoring with continuous electroencephalography, microdialysis, and intracranial pressure monitoring represents altogether the current state-of-art technology for the intensive care of SAH patients. Moreover, advances in genetic biomarkers to predict clinical VS have shown consistent accuracy which may in the near future allow the early prediction of DIND through a simple blood test. Several clinical trials have tested drugs with theoretical effects on DIND prevention or treatment. Nevertheless, nimodipine remains the Holy Grail in the prevention of clinical VS. Among rescue therapies, the endovascular treatment through intra-arterial vasodilator (verapamil or nicardipine) infusion is the most employed method for DIND reversal; however, there is no good quality evidence comparing results of intra-arterial infusion of vasodilators versus balloon angioplasty. Although we have addressed the most refined technology in the management of SAH and DIND, the clinical experience and strict follow-up in neurointensive care will be determinant for favorable long-term outcomes.

Long-Term Outcomes in Patients with Anemia And Cerebral Venous Thrombosis

BACKGROUND

Anemia is associated with unfavorable functional outcome in ischemic and hemorrhagic stroke. However, the relationship between anemia and prognosis in patients with cerebral venous thrombosis (CVT) has not been studied.

METHODS

Consecutive CVT patients were retrospectively identified from November 2011, through January 2017. Anemia was defined according to the World Health Organization criteria (non-pregnant female hemoglobin level < 120 g/L, pregnant female < 110 g/L and male < 130 g/L), which was further classified as mild, moderate, and severe anemia according to hemoglobin concentration, and as microcytic, normocytic, and macrocytic anemia according to mean corpuscular volume. Unfavorable outcome was defined as modified Rankin Scale (mRS) of 3-6. Factors such as age, sex, coma, malignancy, intracerebral hemorrhage, and straight sinus and/or deep CVT involved, premorbid mRS were adjusted to evaluate the relationship between anemia and prognosis in CVT patients.

RESULTS

A total of 238 CVT patients were included, among whom 73 patients (30.67%) were diagnosed with anemia. Multivariate logistic regression analysis showed that patients with anemia had a higher risk of mRS of 3-6 (OR = 3.62; 95% CI, 1.45-9.01; P = 0.006) and mortality (OR = 5.46; 95% CI, 1.90-15.70; P = 0.002). Subgroup analysis showed that severe anemia was independently associated with mRS of 3-6 (OR = 8.80; 95% CI, 1.90-40.81; P = 0.005) and mortality (OR = 9.82; 95% CI, 1.81-53.25; P = 0.010). Similarly, microcytic anemia increased the risk of mRS of 3-6 (OR = 4.64; 95% CI, 1.48-14.52; P = 0.008) and mortality (OR = 9.68; 95% CI, 2.61-35.91; P = 0.001). In addition, our study also revealed that lower hemoglobin level, evaluated as a continuous variable, was inversely associated with mRS of 3-6 (OR = 0.98; 95% CI, 0.96-0.99; P = 0.007) and mortality (OR = 0.97; 95% CI, 0.95-0.99; P = 0.005).

CONCLUSIONS

Anemia was a significant and independent predictor of unfavorable functional outcome in patients with CVT.

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.

Cerebral Microdialysis Monitoring to Improve Individualized Neurointensive Care Therapy: An Update of Recent Clinical Data

Cerebral microdialysis (CMD) allows bedside semicontinuous monitoring of patient brain extracellular fluid. Clinical indications of CMD monitoring are focused on the management of secondary cerebral and systemic insults in acute brain injury (ABI) patients [mainly, traumatic brain injury (TBI), subarachnoid hemorrhage, and intracerebral hemorrhage (ICH)], specifically to tailor several routine interventions—such as optimization of cerebral perfusion pressure, blood transfusion, glycemic control and oxygen therapy—in the individual patient. Using CMD as clinical research tool has greatly contributed to identify and better understand important post-injury mechanisms—such as energy dysfunction, posttraumatic glycolysis, post-aneurysmal early brain injury, cortical spreading depressions, and subclinical seizures. Main CMD metabolites (namely, lactate/pyruvate ratio, and glucose) can be used to monitor the brain response to specific interventions, to assess the extent of injury, and to inform about prognosis. Recent consensus statements have provided guidelines and recommendations for CMD monitoring in neurocritical care. Here, we summarize recent clinical investigation conducted in ABI patients, specifically focusing on the role of CMD to guide individualized intensive care therapy and to improve our understanding of the complex disease mechanisms occurring in the immediate phase following ABI. Promising brain biomarkers will also be described.

Human recombinant erythropoietin reduces sensorimotor dysfunction and cognitive impairment in rat models of chronic kidney disease

INTRODUCTION

Chronic kidney disease (CKD) can cause anaemia and neurological disorders. Recombinant human erythropoietin (rHuEPO) is used to manage anaemia in CKD. However, there is little evidence on the effects of rHuEPO on behaviour and cognitive function in CKD. This study aimed to evaluate the impact of rHuEPO in sensorimotor and cognitive functions in a CKD model.

METHODS

Male Wistar rats were randomly assigned to 4 groups: control and CKD, with and without rHuEPO treatment (1050 IU per kg body weight, once weekly for 4 weeks). The Morris water maze, open field, and adhesive removal tests were performed simultaneously to kidney damage induction and treatment. Markers of anaemia and renal function were measured at the end of the study.

RESULTS

Treatment with rHuEPO reduced kidney damage and corrected anaemia in rats with CKD. We observed reduced sensorimotor dysfunction in animals with CKD and treated with rHuEPO. These rats also completed the water maze test in a shorter time than the control groups.

CONCLUSIONS

rHuEPO reduces kidney damage, corrects anemia, and reduces sensorimotor and cognitive dysfunction in animals with CKD.

Clinical Use of Cerebral Microdialysis in Patients with Aneurysmal Subarachnoid Hemorrhage-State of the Art

Objective

To review the published literature on the clinical application of cerebral microdialysis (CMD) in aneurysmal subarachnoid hemorrhage (SAH) patients and to summarize the evidence relating cerebral metabolism to pathophysiology, secondary brain injury, and outcome.

Methods

Study selection: Two reviewers identified all manuscripts reporting on the clinical use of CMD in aneurysmal SAH patients from MEDLINE. All identified studies were grouped according to their focus on brain metabolic changes during the early and subacute phase after SAH, their association with mechanisms of secondary brain injury and outcome.

Results

The review demonstrated: (1) limited literature is available in the very early phase before the aneurysm is secured. (2) Brain metabolic changes related to early and delayed secondary injury mechanisms may be used in addition to other neuromonitoring parameters in the critical care management of SAH patients. (3) CMD markers of ischemia may detect delayed cerebral ischemia early (up to 16 h before onset), underlining the importance of trend analysis. (4) Various CMD-derived parameters may be associated with patient outcome at 3–12 months, including CMD-lactate-to-pyruvate-ratio, CMD-glucose, and CMD-glutamate.

Conclusion

The clinical use of CMD is an emerging area in the literature of aneurysmal SAH patients. Larger prospective multi-center studies on interventions based on CMD findings are needed.

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.

Effects of hemoglobin level on the early postsurgical cerebral metabolism in patients with severe traumatic brain injury

OBJECTIVE

The study aims to explore the effects of different levels of haemoglobin (Hb) on early cerebral metabolism in patients with postoperative severe traumatic brain injury (TBI) .

METHOD

Fifty-nine patients were randomly divided into catheter oxygen group and ventilator-assisted respiratory group. Each group was subsequently divided into three subgroups basing on different Hb level: Hb ≤ 70 g/L subgroup, 71 g/L ≤ Hb≤90 g/L subgroup and Hb ≥ 91 g/L subgroup. The blood samples from the femoral artery and the affected side internal jugular vein were, respectively, taken at the same time from the patient after postoperative 3 days.

RESULTS

The incidence of anaemia after severe TBI operation was 88.14%. The VADL and cerebral glucose uptake (CMRglu) in both Hb ≤ 70 g/L and 71 g/L ≤ Hb≤90 g/L patients of oxygen catheter group were less than that in Hb ≥ 91 g/L patients. In the ventilator-assisted breathing group, the VADL and CMRglu of 71 g/L ≤ Hb≤90 g/L patients and Hb ≥ 91 g/L patients were lower than those in Hb ≤ 70 g/L patients. The result from comparing the two 71 g/L ≤ Hb ≤ 90 g/L subgroups showed that the brain metabolic indexs in the ventilator-assisted breathing group were better than those in the catheter oxygen group.

CONCLUSIONS

In severe TBI postoperative patients, Hb≤90 g/L induced decrease in aerobic oxidation in brain tissue. Moreover, for the same Hb level of 71 g/L ≤ Hb≤90 g/L, ventilator-assisted breathing significantly improved cerebral metabolism.

Pre-operative anaemia is associated with total morbidity burden on days 3 and 5 after cardiac surgery: a cohort study

BACKGROUND

Pre-operative anaemia is associated with mortality and red blood cell (RBC) transfusion requirement after cardiac surgery. However, the effect on post-operative total morbidity burden (TMB) is unknown. We explored the effect of pre-operative anaemia on post-operative TMB.

METHODS

Data were drawn from the Cardiac Post-Operative Morbidity Score (C-POMS) development study (n = 442). C-POMS describes and quantifies (0-13) TMB after cardiac surgery by noting the presence/absence of 13 morbidity domains on days 3 (D3), 5 (D5), 8 (D8) and 15 (D15). Anaemia was defined as a haemoglobin concentration below 130 g/l for men and 120 g/l for women.

RESULTS

Most patients were White British (86.1%) and male (79.2%) and underwent coronary artery bypass surgery (67.4%). Participants with pre-operative anaemia (n = 137, 31.5%) were over three times more likely to receive RBC transfusion (OR 3.08, 95%CI 1.88-5.06, p < 0.001), had greater D3 and D5 TMB (5 vs 3, p < 0.0001; 3 vs 2, p < 0.0001, respectively) and remained in hospital 2 days longer (8 vs 6 days, p < 0.0001) than non-anaemic patients. Transfused patients remained in hospital 5 days longer than non-transfused patients (p < 0.0001), had higher TMB on all days (all p < 0.001) and suffered greater pulmonary, renal, GI, neurological, endocrine and ambulation morbidities (p 0.026 to <0.001). Pre-operative anaemia and RBC transfusion were independently associated with increased C-POMS score.

CONCLUSIONS

Pre-operative anaemia and RBC transfusion are independently associated with increased post-operative TMB. Understanding TMB may assist in post-operative patient management to reduce morbidity. We recommend the use of the C-POMS tool as a standard outcome tool in further studies.

The Effect of Packed Red Blood Cell Transfusion on Cerebral Oxygenation and Metabolism After Subarachnoid Hemorrhage

BACKGROUND

Anemia adversely affects cerebral oxygenation and metabolism after subarachnoid hemorrhage (SAH) and is also associated with poor outcome. There is limited evidence to support the use of packed red blood cell (PRBC) transfusion to optimize brain homeostasis after SAH. The aim of this study was to investigate the effect of transfusion on cerebral oxygenation and metabolism in patients with SAH.

METHODS

This was a prospective observational study in a neurological intensive care unit of a university hospital. Nineteen transfusions were studied in 15 consecutive patients with SAH that underwent multimodality monitoring (intracranial pressure, brain tissue oxygen, and cerebral microdialysis). Data were collected at baseline and for 12 h after transfusion. The relationship between hemoglobin (Hb) change and lactate/pyruvate ratio (LPR) orbrain tissue oxygen (PbtO2) was tested using univariate and multivariable analyses.

RESULTS

PRBC transfusion was administered on the median post-bleed day 8. The average Hb concentration at baseline was 8.1 g/dL and increased by 2.2 g/dL after transfusion. PbtO2 increased between hours 2 and 4 post-transfusion and this increase was maintained until hour 10. LPR did not change significantly during the 12-h monitoring period. After adjusting for SpO2, cerebral perfusion pressure, and LPR, the change in Hb concentration was independently and positively associated with a change in PbtO2 (adjusted b estimate = 1.39 [95% confidence interval 0.09-2.69]; P = 0.04). No relationship between the change in Hb concentration and LPR was found.

CONCLUSIONS

PRBC transfusion resulted in PbtO2 improvement without a clear effect on cerebral metabolism prior to SAH.

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.

Management of delayed cerebral ischemia after subarachnoid hemorrhage

For patients who survive the initial bleeding event of a ruptured brain aneurysm, delayed cerebral ischemia (DCI) is one of the most important causes of mortality and poor neurological outcome. New insights in the last decade have led to an important paradigm shift in the understanding of DCI pathogenesis. Large-vessel cerebral vasospasm has been challenged as the sole causal mechanism; new hypotheses now focus on the early brain injury, microcirculatory dysfunction, impaired autoregulation, and spreading depolarization. Prevention of DCI primarily relies on nimodipine administration and optimization of blood volume and cardiac performance. Neurological monitoring is essential for early DCI detection and intervention. Serial clinical examination combined with intermittent transcranial Doppler ultrasonography and CT angiography (with or without perfusion) is the most commonly used monitoring paradigm, and usually suffices in good grade patients. By contrast, poor grade patients (WFNS grades 4 and 5) require more advanced monitoring because stupor and coma reduce sensitivity to the effects of ischemia. Greater reliance on CT perfusion imaging, continuous electroencephalography, and invasive brain multimodality monitoring are potential strategies to improve situational awareness as it relates to detecting DCI. Pharmacologically-induced hypertension combined with volume is the established first-line therapy for DCI; a good clinical response with reversal of the presenting deficit occurs in 70 % of patients. Medically refractory DCI, defined as failure to respond adequately to these measures, should trigger step-wise escalation of rescue therapy. Level 1 rescue therapy consists of cardiac output optimization, hemoglobin optimization, and endovascular intervention, including angioplasty and intra-arterial vasodilator infusion. In highly refractory cases, level 2 rescue therapies are also considered, none of which have been validated. This review provides an overview of current state-of-the-art care for DCI management.

Hematologic counts as predictors of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

PURPOSE

Aneurysmal subarachnoid hemorrhage (SAH) is associated with high morbidity and mortality, but currently no single clinical method or ancillary test can reliably predict which subset of patients will develop delayed cerebral ischemia (DCI). The aim of this study was to find hematologic derangements and clinical factors present during the first 7 days after bleeding that could help identify patients at risk for development of DCI.

MATERIALS AND METHODS

Databank analysis of patients with SAH admitted between 2010 and 2012 in a single center. Data from demographics, imaging, laboratory, and clinical factors were collected. Statistical testing was conducted to test for association to the outcome, and multivariate logistic regression was used to design a predictive model.

RESULTS

Of 55 patients, 14 developed DCI (25%). Anemia and leukocytosis on the third day after bleeding were significantly correlated with the outcome (for anemia: P<.032; confidence interval, 1.12-15.16; odds ratio, 4.12; for leukocytosis: P<.046; confidence interval, 1.03-26.13; odds ratio, 5.18). Anemia and leukocytosis were still statistically significant after adjustment for age, sex, modified Fisher scale, and Hunt-Hess scale.

CONCLUSION

The presence of leukocytosis and anemia during the third day after SAH was statistically correlated with the occurrence of DCI.

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.

Monitoring of brain and systemic oxygenation in neurocritical care patients

Maintenance of adequate oxygenation is a mainstay of intensive care, however, recommendations on the safety, accuracy, and the potential clinical utility of invasive and non-invasive tools to monitor brain and systemic oxygenation in neurocritical care are lacking. A literature search was conducted for English language articles describing bedside brain and systemic oxygen monitoring in neurocritical care patients from 1980 to August 2013. Imaging techniques e.g., PET are not considered. A total of 281 studies were included, the majority described patients with traumatic brain injury (TBI). All tools for oxygen monitoring are safe. Parenchymal brain oxygen (PbtO2) monitoring is accurate to detect brain hypoxia, and it is recommended to titrate individual targets of cerebral perfusion pressure (CPP), ventilator parameters (PaCO2, PaO2), and transfusion, and to manage intracranial hypertension, in combination with ICP monitoring. SjvO2 is less accurate than PbtO2. Given limited data, NIRS is not recommended at present for adult patients who require neurocritical care. Systemic monitoring of oxygen (PaO2, SaO2, SpO2) and CO2 (PaCO2, end-tidal CO2) is recommended in patients who require neurocritical care.

Haemoglobin management in acute brain injury

PURPOSE OF REVIEW

Anaemia is common among patients in the neurocritical care unit (NCCU) and is thought to exacerbate brain injury. However, the optimal haemoglobin (Hgb) level still remains to be elucidated for traumatic brain injury (TBI), subarachnoid haemorrhage (SAH) and acute ischaemic stroke (AIS). This review outlines recent studies about anaemia and the effects of red blood cell transfusion (RBCT) on outcome in TBI, SAH and AIS patients admitted to the NCCU.

RECENT FINDINGS

Patients with severe SAH, AIS and TBI often develop anaemia and require RBCT. In general critical care, a restrictive RBCT strategy (Hgb ~7 g/dl) is preferable in patients without serious cardiac disease. In severe TBI, AIS and SAH, both anaemia and RBCT may negatively influence clinical outcome. However, the appropriate RBCT trigger remains unclear and there is great variance in how these patients are transfused. There is evidence from PET and microdialysis studies in humans that RBCT can favourably influence brain metabolism and oxygenation. This correction of hypoxia or altered metabolism rather than anaemia may be of greater importance.

SUMMARY

Results from general critical care should not be extrapolated to all patients with acute brain injury. Transfusion is not risk free, but RBCT use needs to be considered also in terms of potential benefit.

Blood transfusion is an important predictor of hospital mortality among patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Red blood cell (RBC) transfusion after aneurysmal subarachnoid hemorrhage (aSAH) has been associated with increased mortality but prior studies have not adequately adjusted for transfusion-indication bias.

METHODS

This is a retrospective study of consecutive aSAH patients admitted to the intensive care units of two academic medical centers over a 7-year period. Data collection included demographics, World Federation of Neurosurgical Surgeons score (WFNS), modified Fisher score (mFisher), admission and nadir hemoglobin (Hb) level, vasospasm, cerebral infarction, acute lung injury, and hospital mortality. The association between RBC transfusion and mortality was evaluated using a multivariate logistic regression analysis using the propensity for RBC transfusion as a covariate.

RESULTS

We identified 318 patients. The median age was 54 years (46, 65), and 204 (64 %) were females. Hospital mortality was 13 % (42/318). Seventy-two (23 %) patients were transfused. Predictors of transfusion were admit and nadir Hb levels (p < 0.001), age (p = 0.02), gender (0.008), WFNS score (p < 0.001), mFisher score (p = 0.009), surgical versus endovascular treatment (p < 0.001) and moderate to severe vasospasm (p = 0.025) were predictors of transfusion. After adjustment for probability of receiving RBC transfusion, APACHE IV and nadir Hb, transfusion remained independently associated with hospital mortality (OR 3.16, 95 % CI = 1.02-9.69, p = 0.047).

CONCLUSIONS

Among patients with aSAH, RBC transfusion was independently associated with an increased mortality after adjustment for the most common clinical indications for transfusion.

Anemia is an independent prognostic factor in intracerebral hemorrhage: an observational cohort study

INTRODUCTION

To date only two studies have evaluated anemia status in acute intracerebral hemorrhage (ICH) reporting that on admission anemia (OAA) was associated with larger hematoma volume, and lower hemoglobin levels during hospital stay, which related to poorer outcome. The question remains whether anemia influences outcome through related volume-effects or itself has an independent impact?

METHODS

This single-center investigation included 435 consecutive patients with spontaneous ICH admitted to the Department of Neurology over five years. Functional short- and long-term outcome (3 months and 1 year) were analyzed for anemia status. Multivariate logistic and graphical regression analyses were calculated for associations of anemia and to determine independent effects on functional outcome. It was decided to perform a separate analysis for patients with ICH-volume <30 cm³ (minor-volume-ICH).

RESULTS

Overall short-term-outcome was worse in anemic patients (mRS[4-6] OAA = 93.3% vs. non-OAA = 61.2%, P < 0.01), and there was a further shift towards an increased long-term mortality (P = 0.02). The probability of unfavorable long-term-outcome (mRS[4-6]) in OAA was elevated 7-fold (OR:7.5; P < 0.01). Receiver operating characteristics curve (ROC) analysis revealed a positive but poor association of ICH-volume and anemia (AUC = 0.67) suggesting volume-undriven outcome-effects of anemia (AUC = 0.75). Multivariate regression analyses revealed that anemia, besides established parameters, has the strongest relation to unfavorable outcome (OR:3.0; P < 0.01). This is even more pronounced in minor-volume-ICH (OR:5.6; P < 0.01).

CONCLUSIONS

Anemia seems to be a previously unrecognized significant predictor of unfavorable functional outcome with independent effects beyond its association with larger hemorrhage volumes. The recognition of anemia and its treatment may possibly influence outcome after ICH and as such prospective interventional studies are warranted.

Update on the management of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease. Outcome after SAH is mainly determined by the initial severity of the hemorrhage. Neuroimaging, in particular computed tomography, and aneurysm repair techniques, such as coiling and clipping, as well as neurocritical care management, have improved during the last few years. The management of a patient with SAH should have an interdisciplinary approach with case discussions between the neurointensivist, interventionalist and the neurosurgeon. The patient should be treated in a specialized neurointensive care unit of a center with sufficient SAH case volume. Poor-grade patients can be observed for complications and delayed cerebral ischemia through continuous monitoring techniques in addition to transcranial Doppler ultrasonography such as continuous electroencephalography, brain tissue oxygenation, cerebral metabolism, cerebral blood flow and serial vascular imaging. Neurocritical care should focus on neuromonitoring for delayed cerebral ischemia, management of hydrocephalus, seizures and intracranial hypertension, as well as of medical complications such as hyperglycemia, fever and anemia.

Hemoglobin levels and transfusions in neurocritically ill patients: a systematic review of comparative studies

Introduction

Accumulating evidence suggests that, in critically ill patients, a lower hemoglobin transfusion threshold is safe. However, the optimal hemoglobin level and associated transfusion threshold remain unknown in neurocritically ill patients.

Methods

We conducted a systematic review of comparative studies (randomized and nonrandomized) to evaluate the effect of hemoglobin levels on mortality, neurologic function, intensive care unit (ICU) and hospital length of stay, duration of mechanical ventilation, and multiple organ failure in adult and pediatric neurocritically ill patients. We searched MEDLINE, The Cochrane Central Register of Controlled Trials, Embase, Web of Knowledge, and Google Scholar. Studies focusing on any neurocritical care conditions were included. Data are presented by using odds ratios for dichotomous outcomes and mean differences for continuous outcomes.

Results

Among 4,310 retrieved records, six studies met inclusion criteria (n = 537). Four studies were conducted in traumatic brain injury (TBI), one in subarachnoid hemorrhage (SAH), and one in a mixed population of neurocritically ill patients. The minimal hemoglobin levels or transfusion thresholds ranged from 7 to 10 g/dl in the lower-Hb groups and from 9.3 to 11.5 g/dl in the higher-Hb groups. Three studies had a low risk of bias, and three had a high risk of bias. No effect was observed on mortality, duration of mechanical ventilation, or multiple organ failure. In studies reporting on length of stay (n = 4), one reported a significant shorter ICU stay (mean, -11.4 days (95% confidence interval, -16.1 to -6.7)), and one, a shorter hospital stay (mean, -5.7 days (-10.3 to -1.1)) in the lower-Hb groups, whereas the other two found no significant association.

Conclusions

We found insufficient evidence to confirm or refute a difference in effect between lower- and higher-Hb groups in neurocritically ill patients. Considering the lack of evidence regarding long-term neurologic functional outcomes and the high risk of bias of half the studies, no recommendation can be made regarding which hemoglobin level to target and which associated transfusion strategy (restrictive or liberal) to favor in neurocritically ill patients.