Comparison of induced hypertension, fluid bolus, and blood transfusion to augment cerebral oxygen delivery after subarachnoid hemorrhage

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 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.

Risks of nimodipine dose reduction during the high-risk period for delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

Nimodipine dose reduction is recommended in case of high vasopressor demand after aneurysmal subarachnoid hemorrhage (aSAH). The aim of this study was to assess potential adverse effects of nimodipine reduction during the high-risk period for delayed cerebral ischemia (DCI) and cerebral vasospasm (CVS) between days 5 and 10 after hemorrhage. Demographic and clinical data as well as daily nimodipine dose of aSAH patients admitted between 2010 and 2019 were retrospectively analyzed. Univariable and multivariable regression analyses were performed to identify factors associated with DCI, angiographic CVS, DCI-related infarction, and unfavorable outcome. A total of 205 patients were included. Nimodipine dose reduction occurred in 108 (53%) patients ('nimodipine reduction group'), while 97 patients (47%) received the full dose ('no nimodipine reduction group'), Patients in the 'nimodipine reduction group' had significant worse WFNS and Fisher grades and developed significantly more often DCI and angiographic CVS. DCI-related infarction and unfavorable outcome were also significantly increased in the 'nimodipine reduction group.' 'Reduced nimodipine dose' was the only independent predictor for the occurrence of DCI and angiographic CVS in multivariable regression analysis. 'Poor WFNS grade' and 'reduced nimodipine dose' were identified as independent risk factors for DCI-related infarction while 'older age,' 'poor WFNS grade,' and 'reduced nimodipine dose' were associated with unfavorable outcome at 3 months after discharge. Nimodipine dose reduction during the high-risk period of DCI and CVS between days 5 and 10 after hemorrhage might abrogate the positive prognostic effects of nimodipine and should be critically evaluated.

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.

The effect of induced hypertension in aneurysmal subarachnoid hemorrhage: A narrative review

Aneurysmal subarachnoid hemorrhage ‎(aSAH) ‎accounts for 2-5% of all strokes, and 10%-15% of ‎aSAH patients will not survive until hospital admission. Induced hypertension (IH) is an emerging therapeutic option being used for the treatment of vasospasm in ‎aSAH. For patients with cerebral vasospasm (CVS) consequent to SAH, IH is implemented to increase systolic blood pressure (SBP) in order to optimize cerebral blood flow (CBF) and prevent delayed cerebral ischemia (DCI). Prophylactic use of IH has been associated with the development of vasospasm and cerebral ischemia in SAH patients. Various trials have defined several different parameters to help clinicians decide when to initiate IH in a SAH patient. However, there is insufficient evidence to recommend therapeutic IH in aSAH due to the possible serious complications like myocardial ischemia, development of posterior reversible encephalopathy syndrome (PRES), pulmonary edema, and even rupture of another unsecured aneurysm. This narrative review showed the favorable impact of IH therapy on aSAH patients; however, it is crucial to conduct further clinical and molecular experiments to shed more light on the effects of IH in aSAH.

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.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is a neurologic emergency that requires immediate patient stabilization and prompt diagnosis and treatment. Early measures should focus on principles of advanced cardiovascular life support. The aneurysm should be evaluated and treated in a comprehensive stroke center by a multidisciplinary team capable of endovascular and, operative approaches. Once the aneurysm is secured, the patient is best managed by a dedicated neurocritical care service to prevent and manage complications, including a syndrome of delayed neurologic decline. The goal of such specialized care is to prevent secondary injury, reduce length of stay, and improve outcomes for survivors of the disease.

Neurovascular disease, diagnosis, and therapy: Subarachnoid hemorrhage and cerebral vasospasm

The worldwide incidence of spontaneous subarachnoid hemorrhage is about 6.1 per 100,000 cases per year (Etminan et al., 2019). Eighty-five percent of cases are due to intracranial aneurysms. The mean age of those affected is 55 years, and two-thirds of the patients are female. The prognosis is related mainly to the neurologic condition after the subarachnoid hemorrhage and the age of the patient. Overall, 15% of patients die before reaching the hospital, another 20% die within 30 days, and overall 75% are dead or remain disabled. Case fatality has declined by 17% over the last 3 decades. Despite the improvement in outcome probably due to improved diagnosis, early aneurysm repair, administration of nimodipine, and advanced intensive care support, the outcome is not very good. Even among survivors, 75% have permanent cognitive deficits, mood disorders, fatigue, inability to return to work, and executive dysfunction and are often unable to return to their premorbid level of functioning. The key diagnostic test is computed tomography, and the treatments that are most strongly supported by scientific evidence are to undertake aneurysm repair in a timely fashion by endovascular coiling rather than neurosurgical clipping when feasible and to administer enteral nimodipine. The most common complications are aneurysm rebleeding, hydrocephalus, delayed cerebral ischemia, and medical complications (fever, anemia, and hyperglycemia). Management also probably is optimized by neurologic intensive care units and multidisciplinary teams.

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Aneurysmal Subarachnoid Hemorrhage: the Last Decade

Aneurysmal subarachnoid hemorrhage (SAH) affects six to nine people per 100,000 per year, has a 35% mortality, and leaves many with lasting disabilities, often related to cognitive dysfunction. Clinical decision rules and more sensitive computed tomography (CT) have made the diagnosis of SAH easier, but physicians must maintain a high index of suspicion. The management of these patients is based on a limited number of randomized clinical trials (RCTs). Early repair of the ruptured aneurysm by endovascular coiling or neurosurgical clipping is essential, and coiling is superior to clipping in cases amenable to both treatments. Aneurysm repair prevents rebleeding, leaving the most important prognostic factors for outcome early brain injury from the hemorrhage, which is reflected in the neurologic condition of the patient, and delayed cerebral ischemia (DCI). Observational studies suggest outcomes are better when patients are managed in specialized neurologic intensive care units with inter- or multidisciplinary clinical groups. Medical management aims to minimize early brain injury, cerebral edema, hydrocephalus, increased intracranial pressure (ICP), and medical complications. Management then focuses on preventing, detecting, and treating DCI. Nimodipine is the only pharmacologic treatment that is approved for SAH in most countries, as no other intervention has demonstrated efficacy. In fact, much of SAH management is derived from studies in other patient populations. Therefore, further study of complications, including DCI and other medical complications, is needed to optimize outcomes for this fragile patient population.

Refined Sphenopalatine Ganglion Stimulator Placement and Intensity Setting to Augment Blood Flow and Neurologic Function

Background and Purpose- Two large, randomized trials indicated that sphenopalatine ganglion (SPG) stimulation improves final disability outcome in acute anterior circulation patients with ischemic stroke with confirmed cortical involvement. This study evaluated 2 refinements in SPG stimulation treatment technique: (1) SPG electrode placement with real-time optical tracking guidance; and (2) stimulation intensity comfortable tolerance level selection using non-noxious facial physiological markers. Methods- This study was a single, active arm trial at 4 centers, enrolling patients with anterior circulation ischemic stroke, National Institutes of Health Stroke Scale 1 to 6 including arm weakness subitem score ≥1, not receiving recanalization therapies, and within 24 hours of onset. Stimulation level was set based on ipsilateral facial tingling sensation or lacrimation. SPG stimulation effects were assessed by measuring volumetric blood flow in the ipsilateral common carotid artery by ultrasound and grasp and pinch strength in the affected hand before and during stimulation, and by change in National Institutes of Health Stroke Scale from day 1 to 7. Results- Among 50 enrolled patients, age was median 66 years (interquartile range, 60-74), 44% were female, National Institutes of Health Stroke Scale median was 5 (interquartile range, 4-5), and median onset-to-screening time was 18 hours (interquartile range, 9-20). Median implantation skin-to-skin time was 4 minutes (interquartile range, 3-7), and all 50 implants were placed correctly. Comfortable tolerance level was found based on physiological biomarkers in 96% of patients, including 86% in the optimal, low-medium intensity range. SPG stimulation significantly increased common carotid artery peak systolic and end-diastolic blood flow (44%, P<0.0001; and 52%, P<0.0001) and improved pinch strength (42%, P<0.0001) and grasp strength (26%, P<0.0001). Degree of National Institutes of Health Stroke Scale recovery by day 7 was greater than in matched historic controls, median 75% versus 50%, P=0.0003. Conclusions- SPG stimulator placement with real-time optical tracking guidance was fast and accurate, and selection of stimulation intensity levels based on non-noxious facial tingling and lacrimation was feasible in nearly all patients. SPG stimulation led to cervico-cranial blood flow augmentation and improved hand motor function. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT03551093.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

A Comparison of Pathophysiology in Humans and Rodent Models of Subarachnoid Hemorrhage

Non-traumatic subarachnoid hemorrhage (SAH) affects an estimated 30,000 people each year in the United States, with an overall mortality of ~30%. Most cases of SAH result from a ruptured intracranial aneurysm, require long hospital stays, and result in significant disability and high fatality. Early brain injury (EBI) and delayed cerebral vasospasm (CV) have been implicated as leading causes of morbidity and mortality in these patients, necessitating intense focus on developing preclinical animal models that replicate clinical SAH complete with delayed CV. Despite the variety of animal models currently available, translation of findings from rodent models to clinical trials has proven especially difficult. While the explanation for this lack of translation is unclear, possibilities include the lack of standardized practices and poor replication of human pathophysiology, such as delayed cerebral vasospasm and ischemia, in rodent models of SAH. In this review, we summarize the different approaches to simulating SAH in rodents, in particular elucidating the key pathophysiology of the various methods and models. Ultimately, we suggest the development of standardized model of rodent SAH that better replicates human pathophysiology for moving forward with translational research.

Medically induced hypertension, hypervolaemia and haemodilution for the treatment and prophylaxis of vasospasm following aneurysmal subarachnoid haemorrhage: systematic review

PURPOSE

Arterial vasospasm is a major cause of death and long-term disability following subarachnoid haemorrhage (SAH). The use of medically induced hypertension, hypervolaemia and/or haemodilution is widely practiced for prophylaxis and treatment of vasospasm following SAH. We aimed to determine if the quality of available research is adequate to inform use of haemodynamic management strategies to prevent or treat vasospasm following SAH.

METHODS

Individual searches of the following databases were conducted: The Cochrane Database of Systematic Reviews, The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE and OpenSIGLE. Pertinent randomised clinical trials and cohort studies comparing any element or combination thereof: medically induced hypertension, hypervolaemia, and haemodilution were included. Data were extracted using standardised proformas and risk of bias assessed using a domain-based risk of bias assessment tool.

RESULTS

348 study reports were identified by our literature search. Eight studies were included, three of which examined both volume expansion and medically induced hypertension. Three randomised clinical trials and two cohort studies examining prophylactic volume expansion were included. Two trials of prophylactic medically induced hypertension and two cohort studies were included. One trial and one cohort study of medically induced hypertension for treatment of established vasospasm was included. These trials demonstrated no significant difference in any of the clinical outcome measures studied. No trials of blood transfusion were included.

CONCLUSIONS

There is currently insufficient evidence to determine the efficacy or non-efficacy of intravenous volume expansion, medically induced hypertension or blood transfusion for the treatment or prophylaxis of vasospasm following SAH. All of these approaches have been associated with adverse events, of unclear incidence. The current evidence base therefore cannot be used to reliably inform clinical practice. This is a priority for further research.

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.

Hemoglobin concentrations and RBC transfusion thresholds in patients with acute brain injury: an international survey

Background

The optimal hemoglobin (Hb) threshold at which to initiate red blood cell (RBC) transfusion in patients with acute brain injury is unknown. The aim of this survey was to investigate RBC transfusion practices used with these patients.

Methods

We conducted a web-based survey within various societies of critical care medicine for intensive care unit (ICU) physicians who currently manage patients with primary acute brain injury.

Results

A total of 868 responses were obtained from around the world, half of which (n = 485) were from European centers; 204 (24%) respondents had a specific certificate in neurocritical care, and most were specialists in anesthesiology or intensive care and had less than 15 years of practice experience. Four hundred sixty-six respondents (54%) said they used an Hb threshold of 7–8 g/dl to initiate RBC transfusion after acute brain injury, although half of these respondents used a different threshold (closer to 9 g/dl) in patients with traumatic brain injury, subarachnoid hemorrhage, or ischemic stroke. Systemic and cerebral factors were reported as influencing the need for higher Hb thresholds. Most respondents agreed that a randomized clinical trial was needed to compare two different Hb thresholds for RBC transfusion, particularly in patients with traumatic brain injury, subarachnoid hemorrhage, and ischemic stroke.

Conclusions

The Hb threshold used for RBC transfusion after acute brain injury was less than 8 g/dl in half of the ICU clinicians who responded to our survey. However, more than 50% of these physicians used higher Hb thresholds in certain conditions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1748-4) contains supplementary material, which is available to authorized users.

Blood transfusion indications in neurosurgical patients: A systematic review

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

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.

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.

Regional brain monitoring in the neurocritical care unit

Regional multimodality monitoring has evolved over the last several years as a tool to understand the mechanisms of brain injury and brain function at the cellular level. Multimodality monitoring offers an important augmentation to the clinical exam and is especially useful in comatose neurocritical care patients. Cerebral microdialysis, brain tissue oxygen monitoring, and cerebral blood flow monitoring all offer insight into permutations in brain chemistry and function that occur in the context of brain injury. These tools may allow for development of individual therapeutic strategies that are mechanistically driven and goal-directed. We present a summary of the discussions that took place during the Second Neurocritical Care Research Conference regarding regional brain monitoring.

Acute Stroke: Current Evidence-based Recommendations for Prehospital Care

Introduction

In the United States, emergency medical services (EMS) protocols vary widely across jurisdictions. We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of a patient with a suspected stroke and to compare these recommendations against the current protocols used by the 33 EMS agencies in the state of California.

Methods

We performed a literature review of the current evidence in the prehospital treatment of a patient with a suspected stroke and augmented this review with guidelines from various national and international societies to create our evidence-based recommendations. We then compared the stroke protocols of each of the 33 EMS agencies for consistency with these recommendations. The specific protocol components that we analyzed were the use of a stroke scale, blood glucose evaluation, use of supplemental oxygen, patient positioning, 12-lead electrocardiogram (ECG) and cardiac monitoring, fluid assessment and intravenous access, and stroke regionalization.

Results

Protocols across EMS agencies in California varied widely. Most used some sort of stroke scale with the majority using the Cincinnati Prehospital Stroke Scale (CPSS). All recommended the evaluation of blood glucose with the level for action ranging from 60 to 80mg/dL. Cardiac monitoring was recommended in 58% and 33% recommended an ECG. More than half required the direct transport to a primary stroke center and 88% recommended hospital notification.

Conclusion

Protocols for a patient with a suspected stroke vary widely across the state of California. The evidence-based recommendations that we present for the prehospital diagnosis and treatment of this condition may be useful for EMS medical directors tasked with creating and revising these protocols.

Assessment of circulating blood volume with fluid administration targeting euvolemia or hypervolemia

BACKGROUND

The occurrence of hypovolemia in the setting of cerebral vasospasm reportedly increases the risk for delayed ischemic neurologic deficits. Few studies have objectively assessed blood volume (BV) in response to fluid administration targeting normovolemia (NV) or hypervolemia (HV) and none have done so with crystalloids alone. The primary purpose was to evaluate the BV of patients with SAH receiving crystalloid fluid administration targeting NV or HV.

METHODS

The University of Washington IRB approved the study. Prospectively collected data was obtained from patients enrolled in a clinical trial and a concurrent group of patients who received IV fluids during the ICU stay. We defined a normovolemia (NV) and hypervolemia (HV) group based on the cumulative amount of IV fluid administered in mL/kg from ICU admission to day 5; ≥30-60 mL/kg/day (NV) and ≥60 mL/kg/day (HV), respectively. In a subgroup of patients, BV was measured on day 5 post ictus using iodinated (131)I-labeled albumin injection and the BVA-100 (Daxor Corp, New York, NY). Differences between the NV and HV groups were compared using Student's t-test with assumption for unequal variance.

RESULTS

Twenty patients in the NV and 19 in the HV groups were included. The HV group received more fluid and had a higher fluid balance than the NV group. The subgroup of patients in whom BV was measured on day 5 (n = 19) was not different from the remainder of the cohort with respect to the total amount of administered fluid and net cumulative fluid balance by day 5. BV was not different between the two groups and varied widely.

CONCLUSIONS

Routinely targeting prophylactic HV using crystalloids does not result in a higher circulating BV compared to targeting NV, but the possibility of clinically unrecognized hypovolemia remains.

The critical care management of poor-grade subarachnoid haemorrhage

Aneurysmal subarachnoid haemorrhage is a neurological syndrome with complex systemic complications. The rupture of an intracranial aneurysm leads to the acute extravasation of arterial blood under high pressure into the subarachnoid space and often into the brain parenchyma and ventricles. The haemorrhage triggers a cascade of complex events, which ultimately can result in early brain injury, delayed cerebral ischaemia, and systemic complications. Although patients with poor-grade subarachnoid haemorrhage (World Federation of Neurosurgical Societies 4 and 5) are at higher risk of early brain injury, delayed cerebral ischaemia, and systemic complications, the early and aggressive treatment of this patient population has decreased overall mortality from more than 50% to 35% in the last four decades. These management strategies include (1) transfer to a high-volume centre, (2) neurological and systemic support in a dedicated neurological intensive care unit, (3) early aneurysm repair, (4) use of multimodal neuromonitoring, (5) control of intracranial pressure and the optimisation of cerebral oxygen delivery, (6) prevention and treatment of medical complications, and (7) prevention, monitoring, and aggressive treatment of delayed cerebral ischaemia. The aim of this article is to provide a summary of critical care management strategies applied to the subarachnoid haemorrhage population, especially for patients in poor neurological condition, on the basis of the modern concepts of early brain injury and delayed cerebral ischaemia.

Fluid responsiveness and brain tissue oxygen augmentation after subarachnoid hemorrhage

BACKGROUND

The objective of this study was to investigate the relationship between cardiac index (CI) response to a fluid challenge and changes in brain tissue oxygen pressure (PbtO(2)) in patients with subarachnoid hemorrhage (SAH).

METHODS

Prospective observational study was conducted in a neurological intensive care unit of a university hospital. Fifty-seven fluid challenges were administered to ten consecutive comatose SAH patients that underwent multimodality monitoring of CI, intracranial pressure (ICP), and PbtO(2), according to a standardized fluid management protocol.

RESULTS

The relationship between CI and PbtO(2) was analyzed with logistic regression utilizing generalized estimating equations. Of the 57 fluid boluses analyzed, 27 (47 %) resulted in a ≥ 10 % increase in CI. Median absolute (+5.8 vs. +1.3 mmHg) and percent (20.7 vs. 3.5 %) changes in PbtO(2) were greater in CI responders than in non-responders within 30 min after the end of the fluid bolus infusion. In a multivariable model, a CI response was independently associated with PbtO(2) response (adjusted odds ratio 21.5, 95 % CI 1.4-324, P = 0.03) after adjusting for mean arterial pressure change and end-tidal CO(2). Stroke volume variation showed a good ability to predict CI and PbtO(2) response with areas under the ROC curve of 0.86 and 0.81 with the best cut-off values of 9 % for both responses.

CONCLUSION

Bolus fluid resuscitation resulting in augmentation of CI can improve cerebral oxygenation after SAH.

Aneurysmal subarachnoid haemorrhage from a neuroimaging perspective

Neuroimaging is a key element in the management of patients suffering from subarachnoid haemorrhage (SAH). In this article, we review the current literature to provide a summary of the existing neuroimaging methods available in clinical practice. Noncontrast computed tomography is highly sensitive in detecting subarachnoid blood, especially within 6 hours of haemorrhage. However, lumbar puncture should follow a negative noncontrast computed tomography scan in patients with symptoms suspicious of SAH. Computed tomography angiography is slowly replacing digital subtraction angiography as the first-line technique for the diagnosis and treatment planning of cerebral aneurysms, but digital subtraction angiography is still required in patients with diffuse SAH and negative initial computed tomography angiography. Delayed cerebral ischaemia is a common and serious complication after SAH. The modern concept of delayed cerebral ischaemia monitoring is shifting from modalities that measure vessel diameter to techniques focusing on brain perfusion. Lastly, evolving modalities applied to assess cerebral physiological, functional and cognitive sequelae after SAH, such as functional magnetic resonance imaging or positron emission tomography, are discussed. These new techniques may have the advantage over structural modalities due to their ability to assess brain physiology and function in real time. However, their use remains mainly experimental and the literature supporting their practice is still scarce.

Treatment of subarachnoid hemorrhage

Nontraumatic subarachnoid hemorrhage from intracranial aneurysm rupture presents with sudden severe headache. Initial treatment focuses on airway management, blood pressure control, and extraventricular drain for hydrocephalus. After identifying the aneurysm, they may be clipped surgically or endovascularly coiled. Nimodipine is administered to maintain a euvolemic state and prevent delayed cerebral ischemia (DCI). Patients may receive anticonvulsants. Monitoring includes serial neurologic assessments, transcranial Doppler ultrasonography, computed tomography perfusion, and angiographic studies. Treatment includes augmentation of blood pressure and cardiac output, cerebral angioplasty, and intra-arterial infusions of vasodilators. Although early mortality is high, about one half of survivors recover with little disability.

Impact of clipping versus coiling on postoperative hemodynamics and pulmonary edema after subarachnoid hemorrhage

Volume management is critical for assessment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH). This multicenter prospective cohort study compared the impact of surgical clipping versus endovascular coiling on postoperative hemodynamics and pulmonary edema in patients with SAH. Hemodynamic parameters were measured for 14 days using a transpulmonary thermodilution system. The study included 202 patients, including 160 who underwent clipping and 42 who underwent coiling. There were no differences in global ejection fraction (GEF), cardiac index, systemic vascular resistance index, or global end-diastolic volume index between the clipping and coiling groups in the early period. However, extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) were significantly higher in the clipping group in the vasospasm period. Postoperative C-reactive protein (CRP) level was higher in the clipping group and was significantly correlated with postoperative brain natriuretic peptide level. Multivariate analysis found that PVPI and GEF were independently associated with high EVLWI in the early period, suggesting cardiogenic edema, and that CRP and PVPI, but not GEF, were independently associated with high EVLWI in the vasospasm period, suggesting noncardiogenic edema. In conclusion, clipping affects postoperative CRP level and may thereby increase noncardiogenic pulmonary edema in the vasospasm period. His trial is registered with University Hospital Medical Information Network UMIN000003794.

Red blood cell transfusion: what is the evidence when to transfuse?

PURPOSE OF REVIEW

This review provides a summary of the clinical trials evaluating transfusion thresholds and recommendations for red blood cell transfusion. We highlight the trial results in patients in the critical care setting, undergoing surgery, and patients with gastrointestinal bleed, acute coronary syndrome, and acute brain injury.

RECENT FINDINGS

Clinical trials in hip fracture patients with underlying cardiovascular disease or risk factors, and in cardiac surgery, support the findings from prior studies in intensive care unit patients that restrictive transfusion (7-8 g/dl) is well tolerated even in elderly high-risk patients. Restrictive transfusion strategy (7 g/dl) was further supported by the statistically lower mortality in patients with gastrointestinal bleeding compared with liberal transfusion (10 g/dl) strategy. Pilot trials in acute coronary syndrome raise the possibility that liberal transfusion improves outcome, but large trials are needed.

SUMMARY

A restrictive transfusion strategy of administering red blood cell transfusion in patients with hemoglobin concentration of 7-8 g/dl in most patients is supported by randomized clinical trials. Further randomized clinical trials are needed to establish the optimal transfusion threshold in patients with acute coronary syndrome and brain injury, and to elucidate physiological triggers.

How we do it: acute management of subarachnoid hemorrhage

OBJECTIVES

Acute subarachnoid hemorrhage (SAH) is a neurological emergency with significant potential for long-term morbidity and mortality. We review our management of acute SAH and some of the evidence base supporting our practices.

METHODS

We reviewed our standardized and multi-disciplinary approach to the management of SAH.

RESULTS

Management of SAH treatment can be divided into acute, aneurysmal, waiting, and post-waiting phases. Acute issues upon presentation include hemodynamic and respiratory stability, prevention of rebleeding, and treatment of hydrocephalus. The aneurysm must then be secured through endovascular or microsurgical methods. Observation for signs and symptoms of vasospasm must be closely undertaken. Prevention of subsequent medical complications must also be undertaken. Weaning from cerebrospinal fluid diversion and possible shunting is the final step.

DISCUSSION

Standardized multi-modality management of rebleeding, hydrocephalus, aneurysmal obliteration, vasospasm, cerebral salt wasting, and other medical complications during these phases, is critical.

Delayed neurological deterioration after subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) causes early brain injury (EBI) that is mediated by effects of transient cerebral ischaemia during bleeding plus effects of the subarachnoid blood. Secondary effects of SAH include increased intracranial pressure, destruction of brain tissue by intracerebral haemorrhage, brain shift, and herniation, all of which contribute to pathology. Many patients survive these phenomena, but deteriorate days later from delayed cerebral ischaemia (DCI), which causes poor outcome or death in up to 30% of patients with SAH. DCI is thought to be caused by the combined effects of angiographic vasospasm, arteriolar constriction and thrombosis, cortical spreading ischaemia, and processes triggered by EBI. Treatment for DCI includes prophylactic administration of nimodipine, and current neurointensive care. Prompt recognition of DCI and immediate treatment by means of induced hypertension and balloon or pharmacological angioplasty are considered important by many physicians, although the evidence to support such approaches is limited. This Review summarizes the pathophysiology of DCI after SAH and discusses established treatments for this condition. Novel strategies--including drugs such as statins, sodium nitrite, albumin, dantrolene, cilostazol, and intracranial delivery of nimodipine or magnesium--are also discussed.

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.