Forewarning of hypotensive events using a Bayesian artificial neural network in neurocritical care.

Traumatically brain injured (TBI) patients are at risk from secondary insults. Arterial hypotension, critically low blood pressure, is one of the most dangerous secondary insults and is related to poor outcome in patients. The overall aim of this study was to get proof of the concept that advanced statistical techniques (machine learning) are methods that are able to provide early warning of impending hypotensive events before they occur during neuro-critical care. A Bayesian artificial neural network (BANN) model predicting episodes of hypotension was developed using data from 104 patients selected from the BrainIT multi-center database. Arterial hypotension events were recorded and defined using the Edinburgh University Secondary Insult Grades (EUSIG) physiological adverse event scoring system. The BANN was trained on a random selection of 50% of the available patients (n = 52) and validated on the remaining cohort. A multi-center prospective pilot study (Phase 1, n = 30) was then conducted with the system running live in the clinical environment, followed by a second validation pilot study (Phase 2, n = 49). From these prospectively collected data, a final evaluation study was done on 69 of these patients with 10 patients excluded from the Phase 2 study because of insufficient or invalid data. Each data collection phase was a prospective non-interventional observational study conducted in a live clinical setting to test the data collection systems and the model performance. No prediction information was available to the clinical teams during a patient's stay in the ICU. The final cohort (n = 69), using a decision threshold of 0.4, and including false positive checks, gave a sensitivity of 39.3% (95% CI 32.9-46.1) and a specificity of 91.5% (95% CI 89.0-93.7). Using a decision threshold of 0.3, and false positive correction, gave a sensitivity of 46.6% (95% CI 40.1-53.2) and specificity of 85.6% (95% CI 82.3-88.8). With a decision threshold of 0.3, > 15 min warning of patient instability can be achieved. We have shown, using advanced machine learning techniques running in a live neuro-critical care environment, that it would be possible to give neurointensive teams early warning of potential hypotensive events before they emerge, allowing closer monitoring and earlier clinical assessment in an attempt to prevent the onset of hypotension. The multi-centre clinical infrastructure developed to support the clinical studies provides a solid base for further collaborative research on data quality, false positive correction and the display of early warning data in a clinical setting.

KidsBrainIT: A New Multi-centre, Multi-disciplinary, Multi-national Paediatric Brain Monitoring Collaboration.

OBJECTIVES: Validated optimal cerebral perfusion pressure (CPP) treatment thresholds in children do not exist. To improve the intensive care unit (ICU) management of the paediatric traumatic brain injury (TBI) population, we are forming a new paediatric multi-centre collaboration to recruit standardised ICU data for running and reporting upon models for assessing autoregulation and optimal CCP (CPPopt). MATERIALS AND METHODS: We are adapting the adult BrainIT group's approach to develop a new Paediatric Brain Monitoring and Information Technology Group (KidsBrainIT), which will include a repository to store prospectively collected high-resolution physiological, clinical, and outcome data. In the first phase of this project there are 7 UK Paediatric Intensive Care Units, 1 Spanish, 1 Belgium, and 1 Romanian Centre interested in participating. In subsequent phases, we plan to open recruitment to other centres both within Europe, US and abroad. We are collaborating with the Leuven Group and plan to use their LAx (low-frequency autoregulation index), DATACAR (dynamic adaptive target of active cerebral autoregulation), CPPopt and visualisation methodologies. We also plan to use the continuous diffuse optical monitoring and tomography technology developed in Barcelona as an acute surrogate end-point for optimising brain perfusion. This technology allows non-invasive continuous monitoring of deep tissue perfusion and oxygenation in adults but its clinical application in infants and children with TBI has not been studied previously. RESULTS: We report on the current status of setting up this new collaboration and also on pilot analyses in two centres which are the basis of our rationale for the need for a prospective validation study of CPPopt in children. Specifically, we demonstrated that CPPopt varied with time for each patient during their paediatric intensive care unit (PICU) stay, and the median overall CPPopt levels for children aged 2-6 years, 7-11 years and 12-16 years were 68.83, 68.09, and 72.17 mmHg respectively. Among survivors and patients with favourable outcome (GOS 4 and 5), there were significantly higher proportions with CPP monitoring time within CPPopt (p = 0.04 and p = 0.01 respectively). CONCLUSIONS: There is a need and an interest in forming a multi-centre PICU collaboration for acquiring data and performing analyses for determining validated CPPopt thresholds in the paediatric TBI population. KidsBrainIT is being formed to meet that need.

Neuropsychological alterations and neuroradiological findings in patients with post-traumatic concussion: Results of a pilot study. / Alteraciones neuropsicológicas y hallazgos neurorradiológicos en pacientes con conmoción cerebral postraumática. Resultados de un estudio piloto.

INTRODUCTION: Mild traumatic brain injury (mTBI) has traditionally been considered to cause no significant brain damage since symptoms spontaneously remit after a few days. However, this idea is facing increasing scrutiny. The purpose of this study is to demonstrate the presence of early cognitive alterations in a series of patients with mTBI and to link these findings to different markers of brain damage. METHODS: We conducted a prospective study of a consecutive series of patients with mTBI who were evaluated over a 12-month period. Forty-one (3.7%) of the 1144 included patients had experienced a concussion. Patients underwent a routine clinical evaluation and a brain computed tomography (CT) scan, and were also administered a standardised test for post-concussion symptoms within the first 24hours of mTBI and also 1 to 2 weeks later. The second assessment also included a neuropsychological test battery. The results of these studies were compared to those of a control group of 28 healthy volunteers with similar characteristics. Twenty patients underwent an MRI scan. RESULTS: Verbal memory and learning were the cognitive functions most affected by mTBI. Seven out of the 20 patients with normal CT findings displayed structural alterations on MR images, which were compatible with diffuse axonal injury in 2 cases. CONCLUSIONS: Results from this pilot study suggest that early cognitive alterations and structural brain lesions affect a considerable percentage of patients with post-concussion syndrome following mTBI.

[Atypical ganglioglioma with BRAF V600E mutation: a case report and review of the literature]. / Ganglioglioma atipico con mutacion de BRAF V600E: caso clinico y revision de la bibliografia.

INTRODUCTION: Gangliogliomas are rare tumours that affect young patients, appear predominantly in the temporal lobe and usually begin with epileptic seizures. Histologically they have a grade I of malignancy, with an anaplastic form that is catalogued as grade III in the 2007 WHO classification. Yet, there are tumours that do not meet the criteria of either grade and which offer clear prognostic differences with respect to those of grade I. These tumours would be atypical gangliogliomas (grade II), which are not considered in this classification. From the molecular point of view, the best known alteration in gangliogliomas is the BRAF V600E mutation, which worsens the prognosis of the lesion. The possible use of treatments targeted towards this mutated protein is especially relevant in this disorder. CASE REPORT: A 21-year-old male, who had undergone surgery due to a ganglioglioma on two occasions. The neuro-pathological examination revealed histological features consistent with an intermediate grade of malignancy (grade II), with positive BRAF mutation. CONCLUSIONS: The case presented here, together with those previously reported in the literature, reopens the debate on the definition of gangliogliomas in the 2007 WHO classification, and lends support to the fact that the next classification should again include atypical gangliogliomas (grade II), together with possible genetic mutations and molecular disorders.

TITLE: Ganglioglioma atipico con mutacion de BRAF V600E: caso clinico y revision de la bibliografia.Introduccion. Los gangliogliomas son tumores raros que afectan a pacientes jovenes, aparecen predominantemente en el lobulo temporal y suelen comenzar con crisis epilepticas. Histologicamente corresponden a un grado I de malignidad, con una forma anaplasica catalogada como de grado III en la clasificacion de la Organizacion Mundial de la Salud (OMS) de 2007. Sin embargo, existen tumores que no cumplen criterios de uno u otro grado y que presentan claras diferencias pronosticas respecto a los de grado I. Estos tumores corresponderian a gangliogliomas atipicos (grado II), no contemplados en la citada clasificacion. Desde el punto de vista molecular, la alteracion mas conocida en los gangliogliomas es la mutacion de BRAF V600E, que confiere peor pronostico a la lesion. La posibilidad de utilizar tratamientos dirigidos a esta proteina mutada otorga una especial relevancia a esta alteracion. Caso clinico. Varon de 21 años, intervenido de un ganglioglioma en dos ocasiones, en el que el examen neuropatologico objetivo caracteristicas histologicas compatibles con un grado de malignidad intermedio (grado II) con mutacion positiva a BRAF. Conclusiones. El caso presentado, junto con los descritos previamente en la bibliografia, reabre las controversias sobre la definicion de los gangliogliomas en la clasificacion de la OMS de 2007, y apoya el hecho de que la proxima clasificacion de la OMS deberia volver a incluir los gangliogliomas atipicos (grado II) e integrar posibles mutaciones geneticas y alteraciones moleculares.

Epilepsy in patients with malignant middle cerebral artery infarcts and decompressive craniectomies.

UNLABELLED: Patients with malignant middle cerebral artery (MCA) infarctions who have undergone craniectomy are susceptible to the development of vascular epilepsy. Our objective was to study the factors that might influence the occurrence of seizures in this group of patients. MATERIALS AND METHODS: All patients who developed malignant MCA infarction and had undergone decompressive craniectomy in our center between November 2002 and January 2014 were evaluated. In the subsequent follow-up, we evaluated the clinical outcomes and attempted to identify the factors that were related to the occurrence of seizures. RESULTS: We evaluated a total of 80 patients. The median time at which the craniectomy was performed was 40.5h after the stroke. Seizures occurred in 47.5% of all patients. The mortality rate within the first week was 16%, and of those who survived 53.7% developed seizures; 9% of these seizures were acute symptomatic, and 44.8% were remote. The median onset of remote seizures was seven months, and the majority of these were motor seizures with generalization. Notably, the patients with seizures exhibited longer delays from stroke to craniectomy, greater involvements of the temporal lobe and a higher rate of post-craniectomy recanalization of the occluded artery. Regarding the timing of the surgeries, a significantly greater proportion of those who underwent surgery more than 42h after the stroke developed epilepsy (p=0.004). Logistic regression revealed that only prolonged delay (>42h) independently predicted the development of epilepsy (OR 5.166; IC 95% 1.451-18.389; p=0.011). CONCLUSIONS: More than half of patients with malignant MCA infarcts who underwent decompressive craniectomy developed epilepsy. The occurrence of seizures in these patients was related to the delay to the performance of the craniectomy.

Brainstem auditory and somatosensory evoked potentials: a methodological study to evaluate the reproducibility of two devices.

We aimed to determine whether statistical significant differences exist between the sets of results obtained from two devices used in our department for measuring brainstem auditory evoked potentials (BAEPs) and somatosensory evoked potentials (SEPs). We obtained BAEP and median and posterior tibial nerve SEP values bilaterally in ten healthy subjects. The tests were performed on the same subject using two devices consecutively. The equipment consisted of a Nicolet Viking-IV (Nicolet, Madison, WI, USA) and a Viking Select (Viasys Healthcare, Madison, WI, USA), and the same recording electrodes and stimulator (auditory and electrical) were used without modifying any postural position of the subject. The stimuli and recording parameters were the same for both devices. We obtained 20 sets of data for each type of test. The Bland­Altman plots as well as the one-sample t-test or Wilcoxon signed rank test were used to compare data between the two groups of data sets. We found no significant differences between the sets of values obtained with the two devices. Our analysis indicates that the two devices are equal in recording all different variables of BAEP and SEP, which allows us to combine the BAEP and SEP data obtained from the two devices for follow-up studies involving quantitative statistical methods. This study received institutional approval (protocol number PRAG-154/2013).

Sleep disturbance: a forgotten syndrome in patients with Chiari I malformation.

INTRODUCTION: Chiari type I malformation (CM-I) is characterised by caudal ectopia of the cerebellar tonsils through the foramen magnum. This is associated with brain stem, high spinal cord, and cranial nerve compression phenomena. The most frequent symptoms are occipital headaches and dizziness. Less well-known symptoms are sleep disorders and nocturnal respiratory abnormalities. SOURCES: MEDLINE and information from patients evaluated at the Neurosurgery and Clinical Neurophysiology Departments at Hospital Universitario Vall d'Hebron. DEVELOPMENT: Review article based on data obtained from MEDLINE articles since 1966, using combinations of the following keywords: «Chiari malformation¼ or «Arnold-Chiari malformation¼ and «sleep apnea¼ or «sleep disorders¼. CONCLUSIONS: CM-I patients show a higher prevalence of sleep disorders than that observed in the general population. Some studies report a 50% prevalence of sleep apnea-hypopnea syndrome (SAHS), probably associated with sudden death in some cases. These results support analysing sleep respiratory parameters in theses patients. Identifying SAHS symptoms may help optimise treatment, thereby improving quality of life and prognosis.

[Cortical spreading depolarization phenomena in patients with traumatic and ischemic brain injuries. Results of a pilot study]. / Fenómenos de despolarización cortical propagada en los pacientes con lesiones cerebrales traumáticas e isquémicas. Resultados de un estudio piloto.

OBJECTIVES: To determine the frequency and duration of cortical spreading depolarization (CSD) and CSD-like episodes in patients with traumatic brain injury (TBI) and malignant middle cerebral artery infarction (MMCAI) requiring craniotomy. DESIGN: A descriptive observational study was carried out during 19 months. SETTING: Neurocritical patients. PATIENTS: Sixteen patients were included: 9 with MMCAI and 7 with moderate or severe TBI, requiring surgical treatment. INTERVENTIONS: A 6-electrode subdural electrocorticographic (ECoG) strip was placed onto the perilesional cortex. MAIN VARIABLES OF INTEREST: An analysis was made of the time profile and the number and duration of CSD and CSD-like episodes recorded from the ECoGs. RESULTS: Of the 16 patients enrolled, 9 presented episodes of CSD or CSD-like phenomena, of highly variable frequency and duration. CONCLUSIONS: Episodes of CSD and CSD-like phenomena are frequently detected in the ischemic penumbra and/or traumatic cortical regions of patients with MMCAI who require decompressive craniectomy or of patients with contusional TBI.

Impact of chronic kidney disease on the risk of clinical outcomes in patients with cancer-associated venous thromboembolism during anticoagulant treatment.

BACKGROUND: Information on recurrent venous thromboembolic events (VTEs) and major bleeding risks during anticoagulant treatment in patients with cancer-associated VTEs and chronic kidney disease (CKD) is scarce, although it is of relevance in establishing better tailored management strategies in these patients. OBJECTIVES: We compared risks of recurrent VTEs and major bleeds in cancer-associated VTE patients with and without CKD. METHODS: A total of 1684 patients diagnosed with a cancer-associated VTE between 2001 and 2011 were followed for 180 days after VTE diagnosis. Patients were treated mainly with low-molecular-weight heparin (LMWH) or vitamin-K antagonists (VKA). Primary outcomes were recurrent VTE and major bleeding. Secondary outcome was fatal bleeding. RESULTS: Recurrent VTEs occurred in 15.9/100 patient years (py) in patients without CKD (eGFR > 60 mL min(-1) ), 19.5/100 py in those with CKD stage 3A (eGFR 45-60 mL min(-1) ), 14.9/100 py in those with CKD 3B (eGFR 30-45 mL min(-1) ), and 6.8/100 py in patients with CKD 4-5 (eGFR < 30 mL min(-1) ). Major bleeding occurred in 11.4/100 py in patients without CKD, 18.5/100 py in those with CKD stage 3A, 16.0/100 py in those with CKD 3B, and 40.8/100 py in patients with CKD 4-5. Fatal bleeding occurred in 1.1/100 py, 3.4/100 py, 6.3/100 py and 15.7/100 py, respectively. These increased bleeding risks in CKD patients were mainly observed in those on LMWH treatment, not VKA. CONCLUSIONS: The risk of major bleeding was increased in CKD patients with VTE and cancer, and was most prominent in those treated with LMWH and an eGFR < 30 mL min(-1) . These results indicate that LMWH should be used with caution in this specific population.

Infrared pupillometry. Basic principles and their application in the non-invasive monitoring of neurocritical patients.

INTRODUCTION: Pupil assessment is a fundamental part of the neurological examination. Size and reactivity to light of each pupil should be recorded periodically since changes in these parameters may represent the only detectable sign of neurological deterioration in some patients. However, there is great intraobserver and interobserver variability in pupil examination due to the influence of many factors, such as the difference in ambient lighting, the visual acuity and experience of the examiner, the intensity of the luminous stimulus, and the method used to direct this stimulus. In recent years, digital cameras have incorporated infrared devices allowing the development of user-friendly portable devices that permit repeated, non-invasive examinations of pupil size and its reactivity to light with an objective, accessible and inexpensive method. DEVELOPMENT: The purpose of this review is to describe the fundamentals of infrared pupillometry and discuss potential applications in the monitoring of neurocritical patients. We also present some recommendations in the routine assessment of pupils in neurocritical patients. CONCLUSIONS: The possibility of evaluating the changes in pupil reactivity in an early, objective and almost continuous way provides a new non-invasive monitoring method. This method could improve the predictive factor of neurological deterioration and the bedside monitoring of the neurological state of the patient, avoiding unnecessary examinations and enabling early therapeutic intervention.

Glucose control and outcome in patients with stable diabetes and previous coronary, cerebrovascular or peripheral artery disease. Findings from the FRENA Registry.

AIM: The aim of this study was to address the controversy over the influence of intensive glucose control on the risk for cardiovascular events in patients with Type 2 diabetes. METHODS: FRENA is an ongoing registry of stable outpatients with symptomatic coronary artery disease, cerebrovascular disease or peripheral artery disease. We compared the incidence of subsequent ischaemic events (myocardial infarction, stroke or critical limb ischaemia) in patients with Type 2 diabetes and mean HbA(1c) levels < 7.0% (< 53 mmol/mol) vs. those with HbA(1c) levels > 7.0% (> 53 mmol/mol). RESULTS: Of 974 patients with Type 2 diabetes, 480 (49%) had mean HbA(1c) levels < 7% (< 53 mmol/mol). Over a mean follow-up of 14 months, 126 patients (13%) had subsequent ischaemic events: myocardial infarction (43), stroke (29) and critical limb ischaemia (64). The incidence of subsequent ischaemic events was significantly lower in patients with mean HbA(1c) levels < 7.0% (< 53 mmol/mol) than in those with HbA(1c) levels > 7.0% (> 53 mmol/mol) (8.6 vs. 14 per 100 patient-years; rate ratio 0.6; 95% CI 0.4-0.9). These differences persisted after adjusting for potential confounders. However, this better outcome was only found in patients presenting with coronary artery disease (rate ratio 0.4; 95% CI 0.2-0.8), not in those with cerebrovascular disease (rate ratio 0.9; 95% CI 0.4-2.0) or peripheral artery disease (rate ratio 0.8; 95% CI 0.5-1.3). Patients with mean HbA(1c) levels < 7.0% (< 53 mmol/mol) also had a lower mortality (rate ratio 0.6; 95% CI 0.3-0.99). CONCLUSIONS: In secondary prevention, patients with diabetes and HbA(1c) levels < 7.0% (< 53 mmol/mol) had a lower incidence of subsequent ischaemic events and a lower mortality than those with HbA(1c) levels > 7.0% (> 53 mmol/mol). These differences appeared only in patients with coronary artery disease.

[Primary decompressive craniectomy in patients with aneurysmatic subarachnoid hemorrhage. Results of a pilot study in 11 cases]. / Craniectomía descompresiva primaria en la hemorragia subaracnoidea aneurismática. Resultados deun estudio piloto en 11 casos.

INTRODUCTION: Despite the scientific and technical advances of recent years, aneurysmal subarachnoid hemorrhage (aSAH) continues to present a high morbidity and mortality. This fact, together with the impressive results of the primary decompressive craniotomy (PDC) in the malignant infarction of the middle cerebral artery suggests a possible beneficial effect of decompressive technique in aSAH. We present our experience of a pilot study that PDC was used in patients with poorgrade aSAH with associated intracerebral hematoma. PATIENTS AND METHODS: Between March 1st, 2002 and 31st April, 2008, 342 patients with aneurysmatic subarachnoid hemorrhage (aSAH) were treated at our hospital. Of these, 64 had a poor neurological grade (scores of 4 or 5 of the World Federation of Neurosurgical Societies) at the time of admission. The present study examines 11 of those patients who underwent PDC, which is performed in the same clipping and / or evacuation of an associated hematoma. RESULTS: In three patients PDC was performed after endovascular aneurysm treatment because of the need to evacuate an associated hematoma. In the eight remaining patients, PDC was performed in the same clipping and evacuation of the associated hematoma. Outcome evaluation of these eleven patients was conducted 1 year after the operation assessed by the Glasgow Outcome Scale. Six patients survived, and four of them with good results. The PDC was effective in controlling intracranial pressure in all six surviving patients. However, two of these six patients had unfavorable outcomes. Of the five who didn't survive, one patient died from a delayed epidural-subgaleal hematoma as a complication of the decompressive technique, and the other four patients died because of refractory intracranial hypertension. CONCLUSIONS: Primary DC may be beneficial in selected subgroups of patients with poor-grade aSAH. However, there is a lack of definitive evidence to support a clear recommendation for its use.

[Is lactate a good indicator of brain tissue hypoxia in the acute phase of traumatic brain injury? Results of a pilot study in 21 patients]. / ¿Es el lactato un buen indicador de hipoxia tisular? Resultados de un estudio piloto en 21 pacientes con un traumatismo craneoencefálico.

UNLABELLED: Lactate and the lactate-pyruvate index (LPI) are two hypoxia markers widely used to detect brain tissue hypoxia in patients with acute traumatic brain injury. These two markers have a more complex behavior than expected as they can be abnormally high in circumstances with no detectable brain hypoxia. This condition must be considered in the differential diagnosis because it also reflects an alteration of brain energy metabolism. OBJECTIVES: 1. To describe cerebral energy metabolism characteristics observed in the acute phase of traumatic brain injury (TBI) based on two traditional indicators of anaerobic metabolism: lactate and LPI, 2. To determine the concordance between these two biomarkers in order to classify the incidence of anaerobic metabolism and 3. To classify the different types of metabolic abnormalities found in patients with moderate and severe TBI using both lactate and LPI. MATERIALS AND METHODS: Twenty-one patients were randomly selected from a cohort of moderate or severe TBI patients admitted to the neurotraumatology intensive care unit. All of them who underwent both cerebral microdialysis and brain tissue oxygen monitoring (PtiO(2)). We analyzed the levels of lactate and the LPI for every microvial within the first 96 hours after head trauma. These data were correlated with PtiO(2) values. RESULTS: Lactate levels and the LPI were respectively increased during 49.5% and 38.4% of the monitoring time. The incidence and behavior of high levels of both markers were extremely heterogeneous. The concordance between these two biomarkers to determine episodes of dysfunctional metabolism was very weak (Kappa Index=0.29; IC 95%: 0.24-0.34). Based on the levels of lactate and the LPI, we defined four metabolic patterns: I: L>2.5 mmol/L and LPR>25; II: L>2.5 mmol/L and LPR< or = 25; III: L< or = 2.5 mmol/L and LPR< or = 25; IV: L< or = 2.5 mmol/L and LPR>25). In more than 80% of cases in which lactate or LPI were increased, PtiO(2) values were within the normal range (PtiO(2)> 15 mmHg). CONCLUSIONS: Increased lactate and LPI were frequent findings after acute TBI and in most cases they were not related to episodes of brain tissue hypoxia. Furthermore, the concordance between both biomarkers to classify metabolic dysfunction was weak. LPI and lactate should not be used indistinctly in everyday clinical practice because of the weak correlation between these two markers, the difficulty in their interpretation and the heterogeneous and complex nature of the pathophysiology. Other differential diagnoses apart from tissue hypoxia should always be considered when high lactate and/or LPI are detected in the acute injured brain.

Prenatal mercury contamination: relationship with maternal seafood consumption during pregnancy and fetal growth in the 'EDEN mother-child' cohort.

Maternal seafood intake is of great health interest since it constitutes an important source of n-3 fatty acids, but provides also an important pathway for fetal exposure to Hg. The objective of the present study was to determine associations between Hg contamination and both maternal seafood consumption and fetal growth in French pregnant women. Pregnant women included in the 'EDEN mother-child' cohort study answered FFQ on their usual diet in the year before and during the last 3 months of pregnancy, from which frequencies of seafood intake were evaluated. Total hair-Hg level was determined for the first 691 included women. Associations between Hg level, seafood intake and several neonatal measurements were studied using linear regressions adjusted for confounding variables. The median Hg level for mothers was 0.52 µg/g. Maternal seafood intake was associated with Hg level (r 0.33; P < 0.0001). There was no association between Hg level and fetal growth in the whole sample of women, except for an early negative relationship with biparietal diameter. A positive association was found between seafood intake and fetal growth in overweight women only which remained unchanged after adjustment for Hg level (birth weight: +101 g for a difference of 1 sd in seafood consumption; P = 0.008). Although seafood intake was associated with Hg contamination in French pregnant women, the contamination level was low. There was no consistent association between Hg level and fetal growth. Taking into account Hg level did not modify associations between seafood intake and fetal growth.

[Cognitive event-related brain potentials (P300) in patients with normal pressure hydrocephalus. Results of a prospective study]. / Potenciales evocados cognitivos (P300) en pacientes con hidrocefalia de presión normal.

OBJECTIVE: To determine the response to cognitive event-related potentials (P300) in patients with normal-pressure hydrocephalus (NPH) and their relationship with clinical and cognitive status before and after shunt surgery. METHODS: We performed a prospective study in a series of 26 patients with NPH who underwent clinical and cognitive assessment before surgery and 6 months afterwards. Visual P300 potentials obtained before and after treatment were also compared with those obtained in 18 healthy volunteers. RESULTS: Before shunting, the P300 wave was detected in 11 (42.3%) NPH patients, compared with the 18 (100%) volunteers. Six months after shunting, the P300 wave was found in 20 (76.9%) NPH patients. P300 latency was significantly longer in NPH patients than in the control group before surgery, but not at 6 months after surgery. No significant differences in neuropsychological studies or in the level of dependence for daily life activities were found between the subgroups of NPH patients with and without pre-surgical P300 waves, or between changes in P300 parameters and clinical and cognitive changes. CONCLUSIONS: The P300 wave was delayed or undetectable in a substantial percentage of patients with NPH before surgery. These alterations can be reversed by shunting. P300 analysis and neuropsychological tests could be complementary measures to evaluate functional status in patients with NPH.

[High-resolution microdialysis. methodological issues and application to the study of inflammatory brain response]. / Microdiálisis de alta resolución. Aspectos metodológicos y aplicación al estudio de larespuesta inflamatoria cerebral.

Cerebral microdialysis is a tool that provides very relevant information in the metabolic monitoring of brain injured patients. It is a particularly effective technique for the detection and analysis of small molecules, given that the pores of the dialysis membrane act as a barrier to restrict the transport of larger species, such as proteins and other macromolecules. The recent availability of microdialysis catheters with membrane pores of larger size, termed "high resolution" catheters, would widen the spectrum of molecules detectable in the dialisate. However, there are technical complications related to the use of these catheters for such purposes, and therefore, this potential capacity for the recovery of proteins needs to be validated, in order to begin its application as a tool in studies of proteomics associated with brain injuries. The following review depicts the basic principles of microdialysis, and describes some of the issues involved in the recovery of molecules in the dialisate, including the physical properties of the dialysis membrane and of the molecules of interest.

[Cognitive impairment in normal pressure hydrocephalus (NPH). A proposal for clinical evaluation protocol]. / Alteraciones cognitivas en pacientes con hidrocefalia crónica del adulto ("normotensiva"). Propuesta de un protocolo para su evaluación clínica.

Normal pressure hydrocephalus (NPH) is characterized by gait disturbance, urinary incontinence and dementia, and is associated with variable ventricular enlargement. The most accepted treatment of NPH is the placement of a cerebrospinal fluid shunt. Owing to the characteristics of the patients and the invasive nature of the surgical treatment, it is fundamental to detect those patients who could obtain a greater benefit from the treatment. Neuropsychological assessment of these patients could significantly contribute to a better diagnosis of NPH, determining a cognitive deterioration profile for these patients, allowing the assessment of treatment efficacy and helping to detect other additional causes of dementia. The aim of this study is to describe the cognitive deterioration profile of NPH patients and to present the clinical, functional and neuropsychological assessment protocol used in our hospital.

[Detection of episodes of ischemic tissue hypoxia by means of the combined intraoperative neurophysiologic monitoring with the tissue oxygenation monitoring in aneurysm surgery]. / Detección de episodios de hipoxia tisular isquémica mediante la monitorizaciónneurofisiológica intraoperatoria combinada con la monitorización de la oxigenacióntisular en la cirugía aneurismática.

INTRODUCTION: Intraoperative neuromonitoring in aneurysm surgery can be very useful to determine inadequate positions of the vascular clip that cause partial or complete compromise of the cerebral sanguineous flow in the vascular territories irrigated by the arteries related to aneurysm. The direct visualization of these arteries after the application of the surgical clip can be insufficient in detecting this potentially detrimental situation. Knowing this circumstance on the onset would allow the neurosurgeon to correct it and to avoid, therefore, cerebral ischemic tissue hypoxia. We show the utility of the intraoperative monitoring of the oxygen tissue pressure (PtiO2) and the somatosensorial evoked potential (SSEP) for the detection of these situations with the example of a clinical case. CLINICAL CASE: We present the case of a 62 year-old woman, that presented with subarachnoid hemorrhage of aneurysmal origin. The cerebral arteriography demonstrated the existence of an aneurysm of the posterior communicating artery that was treated initially by endovascular procedure with partial exclusion of the aneurysm. For this reason it was decided to complete the treatment with a programmed surgery. The patient was put on an intraoperative monitoring system with a PtiO2 sensor located in the risk area and with SSEP. After positioning the surgical clip the partial oxygen pressure decreased rapidly, as well as the amplitude of the cortical potential of the left posterior tibial nerve. The knowledge of this situation allowed the detection of a trapped posterior communicating artery. After correcting this situation by replacing the surgical clip, both variables recovered to their basal values. CONCLUSIONS: The intraoperative PtiO2 monitoring, combined with neurophysiologic monitoring during aneurysm surgery offers a fast and trustworthy form of early detection of ischemic phenomena caused by bad positioning of the surgical clip.

The use of hyperventilation therapy after traumatic brain injury in Europe: an analysis of the BrainIT database.

OBJECTIVE: To assess the use of hyperventilation and the adherence to Brain Trauma Foundation-Guidelines (BTF-G) after traumatic brain injury (TBI). SETTING: Twenty-two European centers are participating in the BrainIT initiative. DESIGN: Retrospective analysis of monitoring data. PATIENTS AND PARTICIPANTS: One hundred and fifty-one patients with a known time of trauma and at least one recorded arterial blood-gas (ABG) analysis. MEASUREMENTS AND RESULTS: A total number of 7,703 ABGs, representing 2,269 ventilation episodes (VE) were included in the analysis. Related minute-by-minute ICP data were taken from a 30 min time window around each ABG collection. Data are given as mean with standard deviation. (1) Patients without elevated intracranial pressure (ICP) (< 20 mmHg) manifested a statistically significant higher P(a)CO(2) (36 +/- 5.7 mmHg) in comparison to patients with elevated ICP (> or = 20 mmHg; P(a)CO(2): 34 +/- 5.4 mmHg, P < 0.001). (2) Intensified forced hyperventilation (P(a)CO(2) < or = 25 mmHg) in the absence of elevated ICP was found in only 49 VE (2%). (3) Early prophylactic hyperventilation (< 24 h after TBI; P(a)CO(2) < or = 35 mmHg, ICP < 20 mmHg) was used in 1,224 VE (54%). (4) During forced hyperventilation (P(a)CO(2) < or = 30 mmHg), simultaneous monitoring of brain tissue pO(2) or S(jv)O(2) was used in only 204 VE (9%). CONCLUSION: While overall adherence to current BTF-G seems to be the rule, its recommendations on early prophylactic hyperventilation as well as the use of additional cerebral oxygenation monitoring during forced hyperventilation are not followed in this sample of European TBI centers. DESCRIPTOR: Neurotrauma.