Brain Ischemia In Patients Research Articles

Prevalence and risk factors of ischemic monocular vision loss and concurrent brain ischemia.

We performed a retrospective cohort study to identify predictors of concurrent asymptomatic brain ischemia in patients with ischemic monocular vision loss. An inpatient database research of admissions to the Helios University Hospital Wuppertal, Germany between 01/2016 and 12/2020 was conducted. Inclusion criteria were confirmed diagnosis of transient monocular vision loss (MVL), retinal artery occlusion (RAO), and magnetic resonance imaging (MRI) of the brain within 10 days of MVL. Silent brain ischemia (SBI) was defined as diffusion restrictions with corresponding reduced apparent diffusion coefficient in MRI and an absence of neurological deficits besides those complying with MVL in clinical examination. The prevalence and cardiovascular predictors of SBI were analyzed with logistic regression and an artificial neural network. One hundred fourteen out of 475 patients treated with monocular vision loss were included in this study. The mean age was 67.7 ± 13.6 years. 48.2% were male and 47.4% had RAO. MRI scan of the brain was performed after 3.9 ± 2.3 days and detected SBI in 17%. Age ⩾67 years, cardiac etiology of MVL, and cerebral ischemia in medical history were revealed as predictors of SBI in MRI. Patients older than 66 years, with a suspected cardiac embolism as the cause of RAO and previous cerebral ischemia, are more likely to present SBI in cerebral MRI. Therefore, MR imaging, particularly in these patients, can be useful.

Cognitive impairment restoration in patients suffered with stroke during the post-COVID period

Frequency of vascular complications, including strokes, in patients suffered from COVID-19 infection is known to be increased up to 8 times, especially compared with influenza. The purpose: to investigate the fundamental mechanisms of brain ischemia in the patients with mnestic dysfunctions who previously underwent COVID-19 through pharmacocorrection via Phenibut (g-amino-b-phenylbutyric acid hydrochloride) and magnetic therapy in the early recovery period of ischemic stroke. The authors describe the possibilities of cognitive rehabilitation for people who have had ischemic stroke in the post-COVID period. Considering that the presence of mnestic dysfunctions has a negative impact on the process of rehabilitation of cerebral accidents, the fundamental mechanisms of brain ischemia in patients with mnestic dysfunctions in the early recovery period in patients who have undergone COVID-19 have been studied through pharmacocorrection via Phenibut (g-amino-b-phenylbutyric acid hydrochloride) and magnetic therapy. 46 patients aged 40 to 60 years were examined. A comparative study of three randomized clinical groups of patients with separate and complex use of Phenibut and magnetic stimulation. The effectiveness of the proposed therapy in restoring executive functions was established on the basis of indicators of the MMSE scale, the test for the study of frontal dysfunction – FAB, regression of depressive symptoms and is characterized by a decrease in the score on the GDS scale. The authors conclude that mnestic disorders are a functional "target" in cerebral ischemia in the post-COVID period, which requires close attention in relation to pharmacocorrection methods and comprehensive rehabilitation and further research, including the elucidate the pathogenetic mechanisms of cerebral ischemia.

Examination of Genetic Variants Revealed from a Rat Model of Brain Ischemia in Patients with Ischemic Stroke: A Pilot Study.

Although there has been great progress in understanding the genetic bases of ischemic stroke (IS), many of its aspects remain underexplored. These include the genetics of outcomes, as well as problems with the identification of real causative loci and their functional annotations. Therefore, analysis of the results obtained from animal models of brain ischemia could be helpful. We have developed a bioinformatic approach exploring single nucleotide polymorphisms (SNPs) in human orthologues of rat genes expressed differentially under conditions of induced brain ischemia. Using this approach, we identified and analyzed nine SNPs in 553 Russian individuals (331 patients with IS and 222 controls). We explored the association of SNPs with both IS outcomes and with the risk of IS. SNP rs66782529 (LGALS3) was associated with negative IS outcomes (p = 0.048). SNPs rs62278647 and rs2316710 (PTX3) were associated significantly with IS (p = 0.000029 and p = 0.0025, respectively). These correlations for rs62278647 and rs2316710 were found only in women, which suggests a sex-specific association of the PTX3 polymorphism. Thus, this research not only reveals some new genetic associations with IS and its outcomes but also shows how exploring variations in genes from a rat model of brain ischemia can be of use in searching for human genetic markers of this disorder.

Хронічна ішемія мозку у хворих з артеріальною гіпертензією та гіпотиреозом

Розглядаються питання патогенезу хронічної ішемії мозку у хворих з артеріальною гіпертензією та гіпотиреозом. Наведено приклади деяких результатів власних досліджень авторів. За результатами досліджень, у пацієнтів із гіпертонічною дисциркуляторною енцефалопатією та гіпотиреозом відзначаються погіршення кровопостачання головного мозку за рахунок зменшення реактивності судинної стінки, зниження функціональної активності головного мозку, погіршення когнітивних функцій та підвищення рівня тривожності та депресії.

Intra-Operative Hypotension is a Risk Factor for Post-operative Silent Brain Ischaemia in Patients With Pre-operative Hypertension Undergoing Carotid Endarterectomy

Intra-operative haemodynamic instability during carotid endarterectomy (CEA) has been associated with an increased risk of procedural stroke. Diffusion weighted imaging (DWI) lesions have been proposed as a surrogate marker for peri-operative silent cerebral ischaemia. This study aimed to investigate the relationship between peri-operative blood pressure (BP) and presence of post-operative DWI lesions in patients undergoing CEA. A retrospective analysis was performed based on patients with symptomatic CEA included in the MRI substudy of the International Carotid Stenting Study. Relative intra-operative hypotension was defined as a decrease of intra-operative systolic BP≥20% compared with pre-operative ('baseline') BP, absolute hypotension was defined as a drop in systolic BP<80mmHg. The primary endpoint was the presence of any new DWI lesions on post-operative MRI (DWI positive). The occurrence and duration of intra-operative hypotension was compared between DWI positive and DWI negative patients as was the magnitude of the difference between pre- and intra-operative BP. Fifty-five patients with symptomatic CEA were included, of whom eight were DWI positive. DWI positive patients had a significantly higher baseline systolic (186±31 vs. 158±27mmHg, p=.011) and diastolic BP (95±15 vs. 84±13mmHg, p=.046) compared with DWI negative patients. Other pre-operative characteristics did not differ. Relative intra-operative hypotension compared with baseline occurred in 53/55 patients (median duration 34min; range 0-174). Duration of hypotension did not differ significantly between the groups (p=.088). Mean systolic intra-operative BP compared with baseline revealed a larger drop in BP (-37±29mmHg) in DWI positive compared with DWI negative patients (-14±26mmHg, p=.024). Absolute intra-operative systolic BP values did not differ between the groups. In this exploratory study, high pre-operative BP and a larger drop of intra-operative BP were associated with peri-procedural cerebral ischaemia as documented with DWI. These results call for confirmation in an adequately sized prospective study, as they suggest important consequences for peri-operative haemodynamic management in carotid revascularisation.

Thiazolidinediones and ischemic stroke (literature review and reasoning for the new potential treatment approaches)

Stroke is a leading cause of death and disability among adult population. Many pathological events including inflammation, oxidative stress, and apoptosis contribute to the secondary neuronal death after stroke. The goal of this review is to discuss the therapeutic potential and putative mechanisms of neuroprotective properties of thiazolidinediones (peroxisome proliferator-activated receptors-γ agonists) at ischemic stroke. Thiazolidinediones have insulin-sensitizing and other additional pleiotropic properties. Ischemic neuroprotection afforded by thiazolidinediones has been involved anti-inflammatory, anti-oxidant, anti-apoptotic properties, as well as effects on endothelial function and repair. These novel actions of thiazolidinediones could offer some protection against the potentially enhanced damage of brain ischemia in patients with abdominal obesity and insulin resistance and may open new exciting lines of investigation on stroke treatment.

Significance of CT perfusion examination of cerebral blood flow for assessing the risk of brain ischemia in patients with intracranial arterial aneurysm ruptures

The study purpose was to evaluate the significance of cerebral blood flow indicators obtained by CT perfusion for prediction of delayed cerebral ischemia and postoperative ischemic complications to optimize treatment of patients with ruptures of intracranial arterial aneurysms. The study included 70 patients who underwent aneurysm clipping and 42 non-operated patients. The inclusion criteria were as follows: WFNS grade I-III condition, vasospasm according to transcranial Doppler sonography, and availability of CT scans, including CT perfusion data. The vasospasm severity and perfusion indicators _(rCBV and MTT) were evaluated. The severity of subarachnoid and ventricular hemorrhage was evaluated according to the A. Hijdra method. The final results were evaluated using a clinical-statistical method, including ROC analysis. An analysis of the obtained data revealed that the risk of delayed cerebral ischemia and postoperative ischemia increases significantly if the baseline hemispheric CBF value is below a threshold of 40 ml/100 g/min, and the baseline MMT indicator is above a threshold of 5 s. There was asymmetry of these CT perfusion indicators due to a larger deviation from the threshold values in the homolateral hemisphere compared to the opposite side. The ROC analysis results demonstrated diagnostic sensitivity and diagnostic specificity of the CT perfusion technique. The CT perfusion data together with the SAH severity and localization indicators may be used as predictors for the cerebral ischemia outcome in choosing the optimal timing of aneurysm clipping during the acute SAH period in patients in a WFNS grade I-III condition and with signs of mild or moderate vasospasm.

A pilot study of hyperoxemia on neurological injury, inflammation and oxidative stress.

Normobaric hyperoxia is used to alleviate secondary brain ischaemia in patients with traumatic brain injury (TBI), but clinical evidence is limited and hyperoxia may cause adverse events. An open label, randomised controlled pilot study comparing blood concentrations of reactive oxygen species (ROS), interleukin 6 (IL-6) and neuron-specific enolase (NSE) between two different fractions of inspired oxygen in severe TBI patients on mechanical ventilation. We enrolled 27 patients in the Fi O2 0.40 group and 38 in the Fi O2 0.70 group; 19 and 23 patients, respectively, completed biochemical analyses. In baseline, there were no differences between Fi O2 0.40 and Fi O2 0.70 groups, respectively, in ROS (64.8 nM [22.6-102.1] vs. 64.9 nM [26.8-96.3], P = 0.80), IL-6 (group 92.4 pg/ml [52.9-171.6] vs. 94.3 pg/ml [54.8-133.1], P = 0.52) or NSE (21.04 ug/l [14.0-30.7] vs. 17.8 ug/l [14.1-23.9], P = 0.35). ROS levels did not differ at Day 1 (24.2 nM [20.6-33.5] vs. 29.2 nM [22.7-69.2], P = 0.10) or at Day 2 (25.4 nM [21.7-37.4] vs. 47.3 nM [34.4-126.1], P = 0.95). IL-6 concentrations did not differ at Day 1 (112.7 pg/ml [65.9-168.9) vs. 83.9 pg/ml [51.8-144.3], P = 0.41) or at Day 3 (55.0 pg/ml [34.2-115.6] vs. 49.3 pg/ml [34.4-126.1], P = 0.95). NSE levels did not differ at Day 1 (15.9 ug/l [9.0-24.3] vs. 15.3 ug/l [12.2-26.3], P = 0.62). There were no differences between groups in the incidence of pulmonary complications. Higher fraction of inspired oxygen did not increase blood concentrations of markers of oxidative stress, inflammation or neurological injury or the incidence of pulmonary complications in severe TBI patients on mechanical ventilation.

Serum Levels of S100b and NSE Proteins in Patients with Non-Transfusion-Dependent Thalassemia as Biomarkers of Brain Ischemia and Cerebral Vasculopathy.

Patients with non-transfusion-dependent thalassemia (NTDT) are at risk of developing brain ischemia. Transcranial Doppler (TCD) has been established as a useful screening tool of cerebrovascular disease in patients with sickle cell disease. Proteins neuron specific enolase (NSE) and S100B are biomarkers that reflect CNS injury. The purpose of this study is to evaluate cerebral vessel vasculopathy and brain damage in NTDT patients using non-invasive methods as TCD and measurement serum levels of NSE and S100B. We included in our study 30 patients with NTDT, aged between 8 and 62 years old (mean: 29.4, median: 32) who presented in our Unit for regular follow-up. We performed in all patients a non-imaging TCD examination and have measured serum S100, NSE and lactate dehydrogenase (LDH) levels. We investigated the possible correlation between TCD results and S100B, NSE and LDH levels as well as between NSE-LDH and S100B-LDH levels by regression analysis. We found a statistically significant relationship for both NSE, S100B with LDH. We also found a statistically significant relationship for S100B and time-averaged mean velocity (TAMV)/peak velocity of left middle cerebral artery (MCA), NSE and pulsatility index (PI)/resistive index (RI) of the left posterior cerebral artery (PCA). TCD results correlated with biomarkers for brain ischemia. This finding enhances the role of TCD as a screening tool for brain ischemia in patients with NTDT.

Correction symptoms of the chronic brain ischemia in patients with arterial hypertension combined neuroprotective drug Olatropil

Actuality: there are more than 12 million people with hypertension and more than 3 million with chronic cerebrovascular disease in Ukraine. This increases the quantity of patients with cognitive deficits and impairs the quality of life of patients with chronic cerebral ischemia.Objective: study the efficiency of the drug neurometabolic olatropil in the treatment of patients with hypertension and chronic brain ischemia.Materials and Methods. The study involved 30 patients of middle and older age with hypertension and symptoms of chronic brain ischemia. All patients before and after 2-month course of treatment olaptropil conducted neuropsychological testing and assessment of severity of autonomic dysfunction, ambulatory blood pressure monitoring.Results. The most significant effect of olatropil was older patients with long experience hypertension. The addition of the drug to the complex therapy of hypertension has led to a decrease in the expression of anxiety and depressive disorders, reduced effects of autonomic dysfunction, meteosensitivity, fatigue and improve sleep quality. It is not observed the dynamics of blood pressure and heart rate according to ABPM.Conclusions. Inclusion nootropic drug Olatropil in the complex therapy of patients with hypertension reduces the severity of anxiety and depressive symptoms, effects of autonomic dysfunction and improve sleep quality. Olatropil can be recommended as symptomatic treatment of initial stages of chronic brain ischemia in patients with middle and old age.

The use of extra-intracranial microanastomosis in the treatment of cerebral ischemia in patients with nontraumatic subarachnoid hemorrhage

to evaluate the use of extra-intracranial microanastomosis (EICMA) in the treatment of brain ischemia in patients with nontraumatic subarachnoid hemorrhage (SAH). In the period from 01.01.14 to 01.07.15, there were 229 surgeries for ruptured intracranial aneurysms performed in the urgent surgery unit. Nine patients with marked and widespread angiospasm, subcompensated and decompensated cerebral ischemia underwent the simultaneous clipping of ruptured intracranial aneurysms and EICMA. The age of patients varied from 32 to 52 years (mean 36 years). The severity of patient's state was assessed as III-IV grades on the Hunt and Hess scale before operation. The surgery was performed 1-2 days after admission to the hospital, 1-8 days after the development of SAH. Excellent and good outcome was recorded in 4 patients, severe disability in 3 patients, fatal outcome in 2 patients. The fatal outcome was due to decompensated cerebral ischemia and progressive angiospasm with the high linear blood flow rate and the following reduction in perfusion in the affected hemisphere. The simultaneous clipping of ruptured intracranial aneurysms and EICMA in the acute stage of SAH of patients with subcompensated cerebral ischemia allow to improve treatment This technique is most applicable for patients with proximal angiospasm of M1- and M2-segments of the middle cerebral artery in the first 24 h of the development of a focal neurological deficit supported by the reduction in perfusion in the corresponding vascular area.

Serum biomarkers for the early diagnosis of TIA: The MIND-TIA study protocol.

BackgroundA Transient Ischaemic Attack (TIA) bears a high risk of a subsequent ischaemic stroke. Adequate diagnosis of a TIA should be followed immediately by the start of appropriate preventive therapy, including antiplatelets. The diagnosis of a TIA based on symptoms and signs only is notoriously difficult and biomarkers of brain ischaemia might improve the recognition, and target management and prognosis of TIA patients. Our aim is to quantify the added diagnostic value of serum biomarkers of brain ischaemia in patients suspected of TIA.Methods/designStudy design: a cross-sectional diagnostic accuracy study with an additional six month follow-up period.Study population: 350 patients suspected of TIA in the primary care setting.Patients suspected of a TIA will be recruited by at least 200 general practitioners (GPs) in the catchment area of seven TIA outpatient clinics willing to participate in the study. In all patients a blood sample will be drawn as soon as possible after the patient has contacted the GP, but at least within 72 h after onset of symptoms. Participants will be referred by the GP to the regional TIA outpatient clinic for additional investigations, including brain imaging. The ‘definite’ diagnosis (reference standard) will be made by a panel consisting of three experienced neurologists who will use all available diagnostic information and the clinical information obtained during the outpatient clinic assessment, and a six month follow-up period. The diagnostic accuracy, and value in addition to signs and symptoms of candidate serum biomarkers will be assessed in terms of discrimination with C statistics, and calibration with plots.We aim to include 350 suspected cases, with 250 patients with indeed definite TIA (or minor stroke) according to the panel.DiscussionWe hope to find novel biomarkers that will enable a rapid and accurate diagnosis of TIA. This would largely improve the management and prognosis of such patients.Trial registrationClinicalTrials.gov Identifier NCT01954329

Brain ischemia in patients with intracranial hemorrhage: pathophysiological reasoning for aggressive diagnostic management.

Patients with intracranial hemorrhage have to be managed aggressively to avoid or minimize secondary brain damage due to ischemia, which contributes to high morbidity and mortality. The risk of brain ischemia, however, is not the same in every patient. The risk of complications associated with an aggressive prophylactic therapy in patients with a low risk of brain ischemia can outweigh the benefits of therapy. Accurate and timely identification of patients at highest risk is a diagnostic challenge. Despite the availability of many diagnostic tools, stroke is common in this population, mostly because the pathogenesis of stroke is frequently multifactorial whereas diagnosticians tend to focus on one or two risk factors. The pathophysiological mechanisms of brain ischemia in patients with intracranial hemorrhage are not yet fully elucidated and there are several important areas of ongoing research. Therefore, this review describes physiological and pathophysiological aspects associated with the development of brain ischemia such as the mechanism of oxygen and carbon dioxide effects on the cerebrovascular system, neurovascular coupling and respiratory and cardiovascular factors influencing cerebral hemodynamics. Consequently, we review investigations of cerebral blood flow disturbances relevant to various hemodynamic states associated with high intracranial pressure, cerebral embolism, and cerebral vasospasm along with current treatment options.

THIAZOLIDINEDIONES AND ISCHEMIC STROKE (LITERATURE REVIEW AND REASONING FOR THE NEW POTENTIAL TREATMENT APPROACHES)

Stroke is a leading cause of death and disability among adult population. Many pathological events including inflammation, oxidative stress, and apoptosis contribute to the secondary neuronal death after stroke. The goal of this review is to discuss the therapeutic potential and putative mechanisms of neuroprotective properties of thiazolidinediones (peroxisome proliferator-activated receptors-? agonists) at ischemic stroke. Thiazolidinediones have insulin-sensitizing and other additional pleiotropic properties. Ischemic neuroprotection afforded by thiazolidinediones has been involved anti-inflammatory, anti-oxidant, anti-apoptotic properties, as well as effects on endothelial function and repair. These novel actions of thiazolidinediones could offer some protection against the potentially enhanced damage of brain ischemia in patients with abdominal obesity and insulin resistance and may open new exciting lines of investigation on stroke treatment.

Comparison of accuracy of jugular venous oxygen saturation, somatosensory evoked potentials and motor evoked potentials in estimation of occurrence of intraoperative cerebral ischemia in patients undergoing clipping of intracranial aneurysm

Objective To compare the accuracy of jugular venous oxygen saturation (SjvO2),somatosensory evoked potentials (SSEPs) and motor evoked potentials (MEPs) in estimation of the occurrence of intraoperative cerebral ischemia in patients undergoing clipping of intracranial aneurysm.Methods Forty-three ASA Ⅰ or Ⅱ patients of both sexes,aged 18-64 yr,with a body mass index of 20-25 kg/m2,undergoing clipping of intracranial aneurysm,were studied.Anesthesia was induced with sufentanil,rocuronium and propofol.The patients were tracheal intubated and mechanically ventilated.Anesthesia was maintained with remifentanil and propofol.Blood samples were taken from the jugular bulb for detection of SjvO2 before aneurysm clipping or temporary occlusion of parent artery and at 1,3,10,20 and 30 min after clipping aneurysm or temporary occlusion of parent artery.The amplitude and latency of SSEPs and MEPs were recorded simultaneously.The occurrence of cerebral ischemia estimated by SjvO2,SSEPs and MEPs was recorded.The condition of nerve defect was recorded within 3 days after operation and the gold standard of cerebral ischemia was defined as the occurrence of nerve defect.Results Among 43 patients,14 cases were diagnosed as having brain ischemia.The sensitivity and specificity of SjvO2 in estimation of the occurrence of intraoperative brain ischemia were 71％ and 93％,respectively (P ＜ 0.01).The sensitivity and specificity of SSEPs in estimation of the occurrence of intraoperative brain ischemia were 71％ and 62％,respectively (P ＜ 0.05).When the diagnostic criterion of cerebral ischemia was defincd as a decrease in the amplitude of MEPs or prolongation of the latency MEPs,the sensitivity and specificity of MEPs in estimation of the occurrence of intraoperative brain ischemia were 79 ％ and 52 ％,respectively (P ＞ 0.05).When the diagnostic criterion of cerebral ischemia was defined as a loss of the amplitude of MEPs,the sensitivity and specificity of MEPs in estimation of the occurrence of intraoperative brain ischemia were 57％ and 93％,respectively (P ＜0.05).Conclusion The sensitivity of SjvO2 and SSEPs in estimation of the occurrence of intraoperative brain ischemia is higher,however,the specificity of SjvO2 and MEPs is higher,indicating that SjvO2 is a reliable criteria for estimation of the occurrence of intraoperative brain ischemia in patients undergoing clipping of intracranial aneurysm. Key words: Glomus jugulare; Oximetry; Evoked potentials,somatosensory; Evoked potentials,motor; Monitoring,intraoperative; Brain ischemia

Magnetic resonance imaging to determine the incidence of brain ischaemia in patients with β-thalassaemia intermedia

One complication in patients with beta-thalassaemia who had prolonged survival is chronic hypercoagulable state, which results in thromboembolic events involving major organs including the brain. We determined the prevalence of microthrombosis in the brain in an asymptomatic subgroup of patients with b-thalassaemia intermedia (TI) who had undergone splenectomy. This retrospective review included 200 patients with TI diagnosed on the basis of blood count, haemoglobin (Hb) electrophoresis and clinical data. Their ages ranged from 18 to 34 years, 19 (63.3%) were women and 11 (36.7%) were men. We selected 30 patients at random who fulfilled the inclusion criteria: Hb concentration >7 g/dl), splenectomy and platelet count >500,000/ml. Their mean Hb concentration was 8.4 g/dl and their mean ferritin concentration was 519 ng/ml. Magnetic resonance imaging (MRI) was done in every patient, and the findings were interpreted by an expert neuroradiologist. Imaging studies showed pathological findings in 28% of the patients. Six had changes in the white matter suggestive of ischaemia and two had evidence of small infarctions. 1) In this small subset of patients diagnostic magnetic resonance imaging to monitor early asymptomatic or subclinical vascular damage in the brain can be considered when they reach the age of 20 years, and repeated every 3-5 years. 2) Treatment with antiplatelet aggregants is suggested in patients with documented asymptomatic brain ischaemia. 3) These results require confirmation in a larger group of similar patients with other types of thalassaemia who are multitransfused or have an intact spleen.

Safe and Effective Intravenous Thrombolysis for Acute Ischemic Stroke Caused by Left Atrial Myxoma

Atrial myxoma may be associated with syncope or sudden death attributed to left-sided cardiac outflow obstruction or embolization caused by tumor dislodgement or thrombus formation. Definitive treatment for primary and secondary stroke prevention is surgical resection. The role of thrombolysis in acute brain ischemia in patients with atrial myxoma is not defined. There are few data available regarding safety and efficacy of thrombolytic therapy in acute ischemic strokes caused by atrial myxoma. Prior case reports described partial success using intra-arterial local thrombolysis; however, this is invasive and can be associated with significant complications. A previously reported case of systemic thrombolysis resulted in development of cerebral hemorrhage. We describe a young man who presented with syncope and a dense stroke developing as a complication of atrial myxoma, followed by a remarkable recovery after treatment with intravenous recombinant tissue plasminogen activator and urgent cardiac surgery. Contrary to some expert opinion, systemic thrombolytic therapy may be safely and effectively used to treat acute ischemic strokes from atrial myxoma.

Continuous Electroencephalogram Monitoring in the Intensive Care Unit

Because of recent technical advances, it is now possible to record and monitor the continuous digital electroencephalogram (EEG) of many critically ill patients simultaneously. Continuous EEG monitoring (cEEG) provides dynamic information about brain function that permits early detection of changes in neurologic status, which is especially useful when the clinical examination is limited. Nonconvulsive seizures are common in comatose critically ill patients and can have multiple negative effects on the injured brain. The majority of seizures in these patients cannot be detected without cEEG. cEEG monitoring is most commonly used to detect and guide treatment of nonconvulsive seizures, including after convulsive status epilepticus. In addition, cEEG is used to guide management of pharmacological coma for treatment of increased intracranial pressure. An emerging application for cEEG is to detect new or worsening brain ischemia in patients at high risk, especially those with subarachnoid hemorrhage. Improving quantitative EEG software is helping to make it feasible for cEEG (using full scalp coverage) to provide continuous information about changes in brain function in real time at the bedside and to alert clinicians to any acute brain event, including seizures, ischemia, increasing intracranial pressure, hemorrhage, and even systemic abnormalities affecting the brain, such as hypoxia, hypotension, acidosis, and others. Monitoring using only a few electrodes or using full scalp coverage, but without expert review of the raw EEG, must be done with extreme caution as false positives and false negatives are common. Intracranial EEG recording is being performed in a few centers to better detect seizures, ischemia, and peri-injury depolarizations, all of which may contribute to secondary injury. When cEEG is combined with individualized, physiologically driven decision making via multimodality brain monitoring, intensivists can identify when the brain is at risk for injury or when neuronal injury is already occurring and intervene before there is permanent damage. The exact role and cost-effectiveness of cEEG at the current time remains unclear, but we believe it has significant potential to improve neurologic outcomes in a variety of settings.

S100B as an additional prognostic marker in subarachnoid aneurysmal hemorrhage*

Studies of new neuroprotective approaches in patients with subarachnoid aneurysmal hemorrhage and better family information would benefit from the development of laboratory markers of brain ischemia. The goal of this study was to evaluate mean 15-day S100B for predicting outcomes after subarachnoid aneurysmal hemorrhage. Single center prospective cohort with consecutive inclusions. Anesthesiology and Critical Care Neurosurgical Unit of a university hospital. One hundred nine patients admitted within 48 hrs after subarachnoid aneurysmal hemorrhage onset and treated by surgical clipping or coiling within 48 hrs following admission. We recorded initial World Federation of Neurologic Surgeons and Fisher grades; comorbidities; initial severity; aneurysm location; presence of acute hydrocephalus; presence of intraventricular hemorrhage; initial seizures and neurogenic lung edema; initial troponin values; treatment of aneurysm; and occurrence of vasospasm. S100B was assayed daily over the first 15 days. Glasgow Outcome Scores were recorded at intensive care unit discharge and after 6 and 12 months. The main outcome criterion was the 12-month Glasgow Outcome Scale score dichotomized as poor (Glasgow Outcome Scale 1-3) or good (Glasgow Outcome Scale 4-5). Seventy percent of patients had good 12-month outcome. Poor outcome was associated with higher initial World Federation of Neurologic Surgeons and Fisher scores, neurogenic lung edema, high mean 15-day S100B but not initial, troponin initial value, intraventricular hemorrhage, angiographically documented vasospasm, all in an univariate manner. After multivariate analysis, only mean 15-day S100B value significantly predicted outcome (p < 0.0005). The best cutoff for the mean 15-day S100B value was 0.23 microg/L (specificity 0.90, 95% confidence interval [CI] 0.81-0.95; sensitivity 0.91, 95% CI 0.75-0.98; area under the curve 0.98, 95% CI 0.87-0.99). S100B elevation over the first 15 days after subarachnoid aneurysmal hemorrhage is associated with poor outcome after subarachnoid aneurysmal hemorrhage. This result supports the use of S100B as a surrogate marker for brain ischemia in patients with subarachnoid aneurysmal hemorrhage.

Lack of utility of arteriojugular venous differences of lactate as a reliable indicator of increased brain anaerobic metabolism in traumatic brain injury

Ischemic lesions are highly prevalent in patients with traumatic brain injuries (TBIs) and are the single most important cause of secondary brain damage. The prevention and early treatment of these lesions is the primary aim in the modem treatment of these patients. One of the most widely used monitoring techniques at the bedside is quantification of brain extracellular level of lactate by using arteriojugular venous differences of lactate (AVDL). The purpose of this study was to determine the sensitivity, specificity, and predictive value of AVDL as an indicator of increases in brain lactate production in patients with TBIs. Arteriojugular venous differences of lactate were calculated every 6 hours using samples obtained though a catheter placed in the jugular bulb in 45 patients with diffuse head injuries (57.8%) or evacuated brain lesions (42.2%). Cerebral lactate concentration obtained with a 20-kD microdialysis catheter implanted in undamaged tissue was used as the de facto gold standard. Six hundred seventy-three AVDL determinations and cerebral microdialysis samples were obtained simultaneously; 543 microdialysis samples (81%) showed lactate values greater than 2 mmol/L, but only 21 AVDL determinations (3.1%) showed an increase in brain lactate. No correlation was found between AVDL and cerebral lactate concentration (p = 0.014, p = 0.719). Arteriojugular venous differences of lactate had a sensitivity and specificity of 3.3 and 97.7%, respectively, with a false-negative rate of 96.7% and a false-positive rate of 2.3%. Arteriojugular venous differences of lactate do not reliably reflect increased cerebral lactate production and consequently are not reliable in ruling out brain ischemia in patients with TBIs. The clinical use of this monitoring method in neurocritical care should be reconsidered.