Pupilometría por infrarrojos. Descripción y fundamentos de la técnica y su aplicación en la monitorización no invasiva del paciente neurocrítico / Infrared pupillometry. Basic principles and their application in the non-invasive monitoring of neurocritical patients

Introducción: La exploración de las pupilas constituye una parte fundamental de la exploración neurológica. El tamaño y la reactividad a la luz de ambas pupilas deben registrarse de forma individual y periódica, dado que una alteración en estos parámetros puede constituir el único signo detectable de deterioro neurológico en determinados pacientes. Sin embargo, existe una gran variabilidad intra-observadores e inter-observadores al analizar estos parámetros, debido a la influencia de una serie de factores tales como la variabilidad en la luz ambiental, la agudeza visual y experiencia del propio observador, intensidad del estímulo luminoso y el método utilizado para dirigir este estímulo. En los últimos años las cámaras digitales han incorporado dispositivos de infrarrojos que han permitido desarrollar equipos digitales portátiles y de fácil manejo, que permiten realizar estudios repetidos y no invasivos del tamaño y reactividad pupilar a la luz con un método objetivo, accesible y económico. Desarrollo: El objetivo de esta revisión es describir los fundamentos de la pupilometría por infrarrojos y discutir sus posibles aplicaciones en la monitorización del paciente neurocrítico. En esta revisión también se incluyen una serie de recomendaciones metodológicas a considerar en la exploración de las pupilas. Conclusiones: La posibilidad de evaluar los cambios en la reactividad pupilar de forma precoz, objetiva y quasi-continua aporta un nuevo método de monitorización no invasivo que podría mejorar el factor predictivo del deterioro neurológico y monitorizar el estado neurológico a la cabecera del paciente, evitando así exámenes innecesarios y permitiendo intervenciones terapéuticas precoces(AU)

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(AU)

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.

[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.

¿Es el lactato un buen indicador de hipoxia tisular? Resultados de un estudio pilotoen 21 pacientes con un traumatismo craneoencefálico / 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

El lactato y el índice lactato-piruvato (LP) son dosmarcadores utilizados para la detección de la hipoxiacerebral en pacientes que han sufrido un traumatismocraneoencefálico (TCE). Estos dos marcadores presentanun comportamiento más complejo de lo que seesperaría debido a que pueden estar anormalmenteelevados en circunstancias que no cursan con hipoxiatisular detectable. Este comportamiento debe ser consideradoen el diagnóstico diferencial puesto que reflejatambién una alteración del metabolismo energéticocerebral.Objetivos. 1. Describir las características del metabolismoenergético cerebral que se observa en la faseaguda de los pacientes que han sufrido un TCE en basea los dos indicadores tradicionales del metabolismoanaeróbico: lactato e índice LP, 2. Determinar la concordanciaentre ambos indicadores para clasificar laincidencia del metabolismo anaeróbico y 3. Clasificarlos diferentes tipos de alteración metabólica que seobserva en los pacientes con un TCE moderado o graveen base a estos dos indicadores.Material y métodos. Se seleccionaron aleatoriamenteveintiún pacientes de una cohorte de pacientes con TCEmoderado o grave admitidos en la unidad de cuidadosintensivos y monitorizados mediante microdiálisis(MD) cerebral y presión tisular de oxígeno (PtiO2). Seanalizaron los niveles de lactato e índice LP de cadamicrovial generado en las primeras 96 horas tras elTCE. Estos datos fueron correlacionados con los valoresde PtiO2.Resultados. El lactato y el índice LP estuvieronelevados el 49,5% y el 38,4% del tiempo totalmonitorizado respectivamente (..) (AU)

Lactate and the lactate-pyruvate index (LPI) aretwo hypoxia markers widely used to detect brain tissuehypoxia in patients with acute traumatic brain injury.These two markers have a more complex behavior thanexpected as they can be abnormally high in circumstances with no detectable brain hypoxia. This conditionmust be considered in the differential diagnosis becauseit also reflects an alteration of brain energy metabolism.Objectives. 1. To describe cerebral energy metabolismcharacteristics observed in the acute phase oftraumatic brain injury (TBI) based on two traditionalindicators of anaerobic metabolism: lactate and LPI,2. To determine the concordance between these twobiomarkers in order to classify the incidence of anaerobicmetabolism and 3. To classify the different types ofmetabolic abnormalities found in patients with moderateand severe TBI using both lactate and LPI.Materials and methods. Twenty-one patients wererandomly selected from a cohort of moderate orsevere TBI patients admitted to the neurotraumatologyintensive care unit. All of them who underwentboth cerebral microdialysis and brain tissue oxygenmonitoring (PtiO2). We analyzed the levels of lactateand the LPI for every microvial within the first 96hours after head trauma. These data were correlatedwith PtiO2 values.Results. Lactate levels and the LPI were respectivelyincreased during 49,5% and 38,4% of the monitoringtime. The incidence and behavior of high levels of bothmarkers were extremely heterogeneous. The concordancebetween these two biomarkers to determineepisodes of dysfucntional metabolism was very weak(Kappa Index=0,29; IC 95%: 0,24-0,34). Based on thelevels of lactate and the LPI, we defined four metabolicpatterns: I: L>2,5 mmol/L and LPR>25; II: L>2,5mmol/L and LPR≤ 25; III: L≤ 2,5 mmol/L and LPR≤25; IV: L≤ 2,5 mmol/L and LPR>25). In more than80% of cases in which lactate or LPI (..) (AU)

[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.

Microdiálisis de alta resolución. Aspectos metodológicos y aplicación al estudio de larespuesta inflamatoria cerebral / High Resolution Microdialysis. Methodological issues and application to the study of inflammatory brain response

La técnica de microdiálisis (MD) cerebral es un instrumentoque proporciona información relevante en lamonitorización del metabolismo cerebral en pacientesneurocríticos. La MD es una técnica especialmente efectivapara la detección y análisis de pequeñas moléculas,puesto que el tamaño de los poros de la membranadializante actúa como barrera restringiendo el paso deespecies mayores, tales como proteínas u otras macromoléculas.La reciente disponibilidad de catéteres demicrodiálisis con poros de mayor calibre, denominadosde “alta resolución”, permite ampliar el rango de moléculasdetectables en el dializado. Sin embargo, existencomplicaciones técnicas relacionadas con la utilizaciónde estos catéteres para estos propósitos, por lo que estacapacidad potencial para la recuperación de proteínasnecesita ser validada antes de su aplicación como herramientapara estudios de proteómica asociados a la lesióncerebral. En esta revisión se contemplan los principiosbásicos de la microdiálisis y los diferentes factores queintervienen en los procesos de recuperación de moléculasen el dializado, tales como las características físicasde la membrana dializante, así como de las moléculasque se desea investigar (AU)

Cerebral microdialysis is a tool that provides veryrelevant information in the metabolic monitoring ofbrain injured patients. It is a particularly effective technique for the detection and analysis of small molecules,given that the pores of the dialysis membrane actas a barrier to restrict the transport of larger species,such as proteins and other macromolecules. The recentavailability of microdialysis catheters with membranepores of larger size, termed “high resolution” catheters,would widen the spectrum of molecules detectablein the dialisate. However, there are technical complicationsrelated to the use of these catheters for suchpurposes, and therefore, this potential capacity for therecovery of proteins needs to be validated, in order tobegin its application as a tool in studies of proteomicsassociated with brain injuries. The following reviewdepicts the basic principles of microdialysis, and describessome of the issues involved in the recovery ofmolecules in the dialisate, including the physical propertiesof the dialysis membrane and of the moleculesof interest (AU)

Estudio anSAFACHILDREN-1 / anSAFACHILDREN-1 study

Fundamentos: En este trabajo se exponen los resultados obtenidos del estudio anSAFACHILDREN-1 realizado durante el curso 20022003 en un centro docente de la localidad de Andújar, Jaén. En dicho centro, Escuelas Profesionales de la Sagrada Familia, se impartió el curso de Técnico en Dietética y Nutrición, de Formación Profesional Ocupacional que organizó la Consejería de Empleo y Desarrollo Tecnológico de la Junta de Andalucía. Con el objetivo de familiarizar a los alumnos del curso con técnicas epidemiológicas, y evaluar los hábitos de alimentación en el desayuno. Métodos: El estudio anSAFACHILDREN-1 es un estudio poblacional diseñado con el objeto de evaluar los hábitos de alimentación en el desayuno y estado nutricional en la población estudiante (3-11 años) del centro antes citado. Tras realizar el trabajo de campo y el procesamiento de los datos, se realizó la comparación de los datos obtenidos. Resultados y conclusión: Los resultados confirmaron que cada vez más niños y adolescentes no desayunan o lo hacen de forma inadecuada. Se obtuvo que el 75 por ciento de los escolares encuestados desayunaban, pero que de estos tan sólo el 27 por ciento incluían lácteos en su primera comida. Además, se observó que numerosos escolares consumían dulces-bollería para comenzar el día en detrimento del consumo de otros alimentos. En el estudio también se determinó las medidas antropométricas más usuales de los sujetos del estudio, observando las diferencias entre ambos sexos por rangos de edad y comparándolas con los percentiles de referencia (AU)