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Background: Cadaveric studies on humans have shown anatomical variabilities in the morphometric characteristics of the tentorial notch. These anatomical variations could influence the worsening of neurocritical patients. Objectives: 1) To investigate the morphometric characteristics of the tentorial notch in neurocritical patients using computed tomography (CT); 2) To investigate the correlation between tentorial notch measurements by CT and by magnetic resonance imaging (MRI); and 3) To analyze the individual variability of the tentorial notch anatomy seen in neurocritical patients. Methods: Prospective series of neurocritical patients was examined. An imaging protocol for measurements was designed for CT and MRI. The level of the agreement of the measurements from CT and MR images was established. According to the measurements found, patients were divided into different types of tentorial notch. Results: We studied 34 neurocritical patients by CT and MRI. Measurements of the tentorial notch via CT and MRI showed significant agreement: concordance correlation coefficient of 0.96 for notch length and 0.85 for maximum width of tentorial notch. Classification of tentorial notch measurements according to the criteria established by Adler and Milhorat, we found the following: 15 patients (58%) corresponded to a "short" subtype; 7 (21%) to "small"; 3 (9%) to "narrow"; 2 (6%) to "wide"; 2 (6%) to “large”; 1 (3%) to “long”; and 4 (12%) to "typical". Conclusions: The anatomical variability of the tentorial notch could be detected in vivo by means of CT scan and MRI. Good agreement between the measurements made using these two imaging methods was found. RESUMEN Antecedentes: Estudios cadavéricos en humanos han mostrado variabilidad anatómica en las características morfométricas de la hendidura tentorial (HT). Estas variaciones anatómicas podrían influir en el neurodeterioro agudo de los pacientes neurocríticos. Objetivos: 1) Investigar las características morfométricas de la HT en pacientes neurocríticos mediante tomografía computarizada (TC); 2) Investigar la correlación de las mediciones de la HT realizadas por TC y resonancia magnética (RM); 3) Analizar la variabilidad individual de la anatomía de la HT observada en pacientes neurocríticos. Métodos: Se examinó una serie prospectiva de pacientes neurocríticos. Se diseñó un protocolo de imágenes para mediciones por TC y RM. Se estableció la concordancia de las mediciones realizadas mediante TC y RM. Según las mediciones encontradas, los pacientes se dividieron en diferentes tipos de HT. Resultados: Estudiamos 34 pacientes neurocríticos por TC y RM. Las mediciones de la HT por TC y RM mostraron una concordancia significativa: coeficiente de correlación de concordancia de 0,96 para la longitud de la HT y 0,85 para el ancho máximo de la HT. Clasificando las medidas de la HT de acuerdo con los criterios establecidos por Adler y Milhorat, encontramos: 15 pacientes (58%) correspondieron al subtipo "corto", 7 (21%) al "pequeño", 3 (9%) al "estrecho" ", 2 (6%) a "ancho ", 2 (6%) al "grande ", 1 (3%) al "largo" y 4 (12%) al "típico". Conclusiones: Se pudo detectar variabilidad anatómica de la HT in vivo, mediante TC y RM. Se encontró una buena concordancia en las medidas obtenidas con ambos métodos imagenológicos.

Resumen Objetivo Evaluar el impacto de la infusion de lactato de sodio 0,5 M sobre variables del medio interno y sobre la presion intracraneana en pacientes criticos. Diseno Estudio prospectivo experimental de cohorte unica. Ambito Unidad de cuidados intensivos de un hospital universitario. Pacientes Pacientes con shock y neurocriticos con hipertension intracraneana. Intervenciones Se infundio una carga de 500 cc de infusion de lactato de sodio 0,5 M en 15 min y se midio el nivel plasmatico de sodio, potasio, magnesio, calcio, cloro, lactato, bicarbonato, PaCO2 arterial, pH, fosfato y albumina en 3 tiempos: T0 preinfusion; T1 a los 30 min y T2 a los 60 min postinfusion. Se midieron la presion arterial media y presion intracraneana en T0 y T2. Resultados Recibieron el fluido N = 41: n = 19 como osmoagente y 22 como expansor. Se constato alcalosis metabolica: T0 vs. T1 (p = 0,007); T1 vs. T2 (p = 0,003). La natremia aumento en los 3 tiempos (T0 vs. T1; p Conclusiones La infusion de lactato de sodio 0,5 M genera alcalosis metabolica, hipernatremia, disminucion de la cloremia y un cambio bifasico del lactato, y muestra eficacia en el descenso de la presion intracraneana en pacientes con dano encefalico agudo.

Objective To evaluate the impact of the infusion of sodium lactate 500 ml upon different biochemical variables and intracranial pressure in patients admitted to the intensive care unit. Design A prospective experimental single cohort study was carried out. Scope Polyvalent intensive care unit of a university hospital. Patients Critical patients with shock and intracranial hypertension. Procedure A 500 ml sodium lactate bolus was infused in 15 min. Plasma levels of sodium, potassium, magnesium, calcium, chloride, lactate, bicarbonate, PaCO2, pH, phosphate and albumin were recorded at 3 timepoints: T0 pre-infusion; T1 at 30 min, and T2 at 60 min post-infusion. Mean arterial pressure and intracranial pressure were measured at T0 and T2. Results Forty-one patients received sodium lactate: 19 as an osmotically active agent and 22 as a volume expander. Metabolic alkalosis was observed: T0 vs. T1 (p = 0.007); T1 vs. T2 (p = 0.003). Sodium increased at the 3 timepoints (T0 vs. T1, p Conclusions The infusion of sodium lactate is associated to metabolic alkalosis, hypernatremia, reduced chloremia, and a biphasic change in plasma lactate levels. Moreover, a decrease in intracranial pressure was observed in patients with acute brain injury.

Objectives: To determine the predictive value of the measurement of the diameter of the optic nerve sheath (ONSD) with ocular ultrasonography compared to invasive intracranial pressure (ICP) measurement for the detection of intracranial hypertension (ICH). Design: Prospective, observational study. Setting: Intensive Care Unit (ICU) of two tertiary university hospitals in Montevideo, Uruguay. Patients: We studied 56 adult patients of both sexes, over 18 years of age, who required sedation, mechanical ventilation, and invasive ICP monitoring (patients with severe, traumatic and non-traumatic AEI) with a Glascow Coma Score (GCS) equal to or less than 8 on admission to the ICU. Interventions: This was a study that utilized non-invasive (minimal risk) ultrasonography in patients admitted to the ICU. Measurements and main results: In our study, a logistic regression model was performed in which it was observed that the variable ONSD is statistically significant with a p value of 0.00803 ( 20 mmHg are correctly identified). Conclusions: In sedated neurocritical patients, with structural Acute Brain Injury, the ONSD measurement strongly correlates with the ICP values measured invasively.

Cerebral critical closing pressure (CrCP) comprises intracranial pressure (ICP) and arteriolar wall tension (WT). It is the arterial blood pressure (ABP) at which small vessels close and circulation stops. We hypothesized that the increase in WT secondary to a systemic hypertensive challenge would lead to an increase in CrCP and that the "effective" cerebral perfusion pressure (CPPeff; calculated as ABP - CrCP) would give more complete information than the "conventional" cerebral perfusion pressure (CPP; calculated as ABP - ICP).This study aimed to compare CrCP, CPP, and CPPeff changes during a hypertensive challenge in patients with a severe traumatic brain injury.Data on ABP, ICP, and cerebral blood flow velocity, measured by transcranial Doppler ultrasound, were acquired simultaneously for 30 min both basally and during a hypertensive challenge. An impedance-based CrCP model was used.The following values are expressed as median (interquartile range). There were 11 patients, aged 29 (14) years. CPP increased from 73 (17) to 102 (26) mmHg (P ≤ 0.001). ICP did not change. CrCP changed from 23 (11) to 27 (10) mmHg (P ≤ 0.001). WT increased from 7 (5) to 11 (7) mmHg (P ˂ 0.005). CPPeff changed less than CPP.The CPP change was greater than the CPPeff change, mainly because CrCP increased simultaneously with the WT increase as a result of the autoregulatory response. CPPeff provides information about the real driving force generating blood movement.

A 26-year-old woman presented a superior sagittal and transverse sinus thrombosis with venous infarction. Anticoagulation was started. Six months later headache and visual impairment developed, and intracranial hypertension was diagnosed-secondary pseudotumor cerebri. It was managed with a lumbo-peritoneal shunt (LPS) resulting in a positive initial evolution with initial symptoms resolution, but headache and visual impairment eventually reappeared. Magnetic Resonance Imaging revealed a Pseudo-Chiari malformation, leading to lumbo-peritoneal shunt removal (Friedman et al. Neurology 81:1159-1165, 2013; Moncho et al. Rev Neurol 56(12):623-634, 2013). As symptoms reappeared, a short period of continuous transcranial Doppler neuromonitoring, including a change of head of bed elevation, was performed. A sudden decrease in cerebral blood flow velocity with a dramatic increase in pulsatility index developed when head of bed was moved from 45° to horizontal position. Transcranial Doppler changes were compatible with a plateau wave of intracranial hypertension. A ventricle-peritoneal shunt was inserted, which resulted in symptomatology, imaging, and digital campimetry improvement.

Introduction: Cerebral critical closing pressure (CrCP) comprises intracranial pressure (ICP) and arteriolar wall tension (WT). It is the arterial blood pressure (ABP) at which small vessels close and circulation stops. We hypothesized that the increase in WT secondary to a systemic hypertensive challenge would lead to an increase in CrCP and that the “effective” cerebral perfusion pressure (CPPeff; calculated as ABP − CrCP) would give more complete information than the “conventional” cerebral perfusion pressure (CPP; calculated as ABP − ICP).

To evaluate cerebrospinal fluid (CSF) and peripheral blood (PB) Treg, TH17 cells, TH1, TH2 and related cytokines in the acute phase of aSAH we assessed TH17, TH1, TH2, T regulatory cells and neutrophils in 39 aneurysmal subarachnoid hemorrhage (aSAH) patients and 56 controls. PB TH17 cells and TH17/Treg ratio were higher in CSF and PB of aSAH patients. Serum and CSF IL-17A levels were increased in aSAH. Serum IL-17A levels were associated with vasospasm and ICU mortality. Study results support the role of TH17/IL17 axis in aSAH pathogenesis, turning it into a potential clinical biomarker and a novel target for research.