Neurocritical care management supported by multimodal brain monitoring after acute brain injury / Abordagem de cuidados neurocríticos apoiada por monitorização cerebral multimodal após lesão cerebral aguda

ABSTRACT Objective: To evaluate the association between different intensive care units and levels of brain monitoring with outcomes in acute brain injury. Methods: Patients with traumatic brain injury and subarachnoid hemorrhage admitted to intensive care units were included. Neurocritical care unit management was compared to general intensive care unit management. Patients managed with multimodal brain monitoring and optimal cerebral perfusion pressure were compared with general management patients. A good outcome was defined as a Glasgow outcome scale score of 4 or 5. Results: Among 389 patients, 237 were admitted to the neurocritical care unit, and 152 were admitted to the general intensive care unit. Neurocritical care unit management patients had a lower risk of poor outcome (OR = 0.228). A subgroup of 69 patients with multimodal brain monitoring (G1) was compared with the remaining patients (G2). In the G1 and G2 groups, 59% versus 23% of patients, respectively, had a good outcome at intensive care unit discharge; 64% versus 31% had a good outcome at 28 days; 76% versus 50% had a good outcome at 3 months (p < 0.001); and 77% versus 58% had a good outcome at 6 months (p = 0.005). When outcomes were adjusted by SAPS II severity score, using good outcome as the dependent variable, the results were as follows: for G1 compared to G2, the OR was 4.607 at intensive care unit discharge (p < 0.001), 4.22 at 28 days (p = 0.001), 3.250 at 3 months (p = 0.001) and 2.529 at 6 months (p = 0.006). Patients with optimal cerebral perfusion pressure management (n = 127) had a better outcome at all points of evaluation. Mortality for those patients was significantly lower at 28 days (p = 0.001), 3 months (p < 0.001) and 6 months (p = 0.001). Conclusion: Multimodal brain monitoring with autoregulation and neurocritical care unit management were associated with better outcomes and should be considered after severe acute brain injury.

RESUMO Objetivo: Avaliar a associação entre diferentes tipos de unidades de cuidados intensivos e os níveis de monitorização cerebral com desfechos na lesão cerebral aguda. Métodos: Foram incluídos doentes com traumatismo craniencefálico e hemorragia subaracnoide internados em unidades de cuidados intensivos. A abordagem na unidade de cuidados neurocríticos foi comparada à abordagem na unidade de cuidados intensivos polivalente geral. Os doentes com monitorização cerebral multimodal e pressão de perfusão cerebral ótima foram comparados aos que passaram por tratamento geral. Um bom desfecho foi definido como pontuação de 4 ou 5 na Glasgow outcome scale. Resultados: Dos 389 doentes, 237 foram admitidos na unidade de cuidados neurocríticos e 152 na unidade de cuidados intensivos geral. Doentes com abordagem em unidades de cuidados neurocríticos apresentaram menor risco de um mau desfecho (Odds ratio = 0,228). Um subgrupo de 69 doentes com monitorização cerebral multimodal (G1) foi comparado aos demais doentes (G2). Em G1 e G2, respectivamente, 59% e 23% dos doentes apresentaram bom desfecho na alta da unidade de cuidados intensivos; 64% e 31% apresentaram bom desfecho aos 28 dias; 76% e 50% apresentaram bom desfecho aos 3 meses (p < 0,001); e 77% e 58% apresentaram bom desfecho aos 6 meses (p = 0,005). Quando os desfechos foram ajustados para o escore de gravidade do SAPS II, usando o bom desfecho como variável dependente, os resultados foram os seguintes: para o G1, em comparação ao G2, a odds ratio foi de 4,607 na alta da unidade de cuidados intensivos (p < 0,001), 4,22 aos 28 dias (p = 0,001), 3,250 aos 3 meses (p = 0,001) e 2,529 aos 6 meses (p = 0,006). Os doentes com abordagem da pressão de perfusão cerebral ótima (n = 127) apresentaram melhor desfecho em todos os momentos de avaliação. A mortalidade desses doentes foi significativamente menor aos 28 dias (p = 0,001), aos 3 meses (p < 0,001) e aos 6 meses (p = 0,001). Conclusão: A monitorização cerebral multimodal com autorregulação e abordagem na unidade de cuidados neurocríticos foi associado a melhores desfechos e deve ser levado em consideração após lesão cerebral aguda grave.

Correlation between hemodynamic characteristics or dynamic cerebral autoregulation and postoperative hyperperfusion in patients undergoing carotid endarterectomy / 中华超声影像学杂志

Objective:To investigate the hemodynamic characteristics and dynamic cerebral autoregulation(dCA) of patients with severe carotid stenosis before carotid endarterectomy(CEA), and to analyze their correlations with hyperperfusion after CEA.Methods:A total of 63 patients with unilateral severe carotid artery atherosclerotic stenosis who underwent CEA were consecutively recruited prospectively in Xuanwu Hospital, Capital Medical University from January 2021 to August 2021. According to postoperative hyperperfusion, patients were divided into hyperperfusion group (13 cases) and non-hyperperfusion group (50 cases). The general clinical data and hemodynamic parameters were compared between the two groups. The dCA was evaluated by the transfer function analysis that measured the fluctuation amplitude of mean cerebral blood flow velocity(CBFV) with blood pressure change, the time difference of phase with blood pressure change, and the correlation between mean CBFV and blood pressure change. The value of dCA for predicting postoperative hyperperfusion was analyzed through the ROC curve and the area under the curve(AUC).Results:①The proportion of hypertension in hyperperfusion group was higher than that in non-hyperperfusion group ( P<0.05). ②The peak systolic velocity (PSV) at the stenosis lesion of the internal carotid artery, the end-diastolic velocity (EDV) at the stenosis lesion of the internal carotid artery and the ratio of PSV at the stenosis lesion of the internal carotid artery to the distal internal carotid artery in the hyperperfusion group were higher than the non-hyperperfusion group.And the PSV of the ipsilateral middle cerebral artery in the hyperperfusion group was lower than the non-hyperperfusion group (all P<0.05). ③In the very low-frequency and low-frequency region, the phase in the hyperperfusion group was lower than that in the non-hyperperfusion group (all P<0.05), while there was no significant difference in the high-frequency regions( P>0.05). In the three regions of very low-frequency, low-frequency and high-frequency, there were no significant differences in the gain and coherence between the two groups(all P>0.05). ④The best cutoff value of phase in the very low-frequency was 33.28 for predicting hyperperfusion after CEA (AUC=0.766, 95% CI=0.629-0.904, P=0.03), with the specificity of 0.700, and sensitivity of 0.846. Conclusions:There are differences in hemodynamics and dCA between the hyperperfusion group and the non-hyperperfusion group after CEA. The impaired preoperative dynamic cerebral autoregulation is an independent predictor of postoperative hyperperfusion.

Study of the relationship between regional cerebral saturation and pCO2 changes during mechanical ventilation to evaluate modifications in cerebral perfusion in a newborn piglet model

Near-infrared spectroscopy (NIRS) could be a useful continuous, non-invasive technique for monitoring the effect of partial pressure of carbon dioxide (PaCO2) fluctuations in the cerebral circulation during ventilation. The aim of this study was to examine the efficacy of NIRS to detect acute changes in cerebral blood flow following PaCO2 fluctuations after confirming the autoregulation physiology in piglets. Fourteen piglets (<72 h of life) were studied. Mean arterial blood pressure, oxygen saturation, pH, glycemia, hemoglobin, electrolytes, and temperature were monitored. Eight animals were used to evaluate brain autoregulation, assessing superior cava vein Doppler as a proxy of cerebral blood flow changing mean arterial blood pressure. Another 6 animals were used to assess hypercapnia generated by decreasing ventilatory settings and complementary CO2 through the ventilator circuit and hypocapnia due to increasing ventilatory settings. Cerebral blood flow was determined by jugular vein blood flow by Doppler and continuously monitored with NIRS. A decrease in PaCO2 was observed after hyperventilation (47.6±2.4 to 29.0±4.9 mmHg). An increase in PaCO2 was observed after hypoventilation (48.5±5.5 to 90.4±25.1 mmHg). A decrease in cerebral blood flow after hyperventilation (21.8±10.4 to 15.1±11.0 mL/min) and an increase after hypoventilation (23.4±8.4 to 38.3±10.5 mL/min) were detected by Doppler ultrasound. A significant correlation was found between cerebral oxygenation and Doppler-derived parameters of blood flow and PaCO2. Although cerebral NIRS monitoring is mainly used to detect changes in regional brain oxygenation, modifications in cerebral blood flow following experimental PaCO2 changes were detected in newborn piglets when no other important variables were modified.

A autorregulação percebida como preditora da utilização de recursos no moodle / Perceived self-regulation as a predictor of resource use in moodle / Lautorégulation perçue como prédictrice de lutilisation de ressources moodle / Autorregulación percibida como predictor del uso de recursos en moodle

Resumo Autorregulação da aprendizagem implica refletir sobre a utilização de recursos educativos para gerir o que, quando, como, com quem e por que aprender. Este artigo pretendeu investigar a relação entre a perceção dos alunos sobre o planeamento, execução e autoavaliação da aprendizagem e a seleção de recursos e atividades do Moodle. Responderam ao Inventário de Recursos e Atividades em Ambientes Moodle e ao Inventário de Aprendizagem Autorregulada em Ambientes Moodle 438 alunos (7º ao 9º ano). Uma análise de regressão mostrou que a perceção dos alunos sobre o planeamento, execução e autoavaliação da aprendizagem prediz a seleção de recursos e atividades de disponibilização de informação e de realização de trabalho, mas não de colaboração/interação em todas as fases de regulação do trabalho.

Abstract Self-regulated learning involves reflecting on the use of educational resources to manage what, when, how, with whom, and why to learn. Thus, this study investigated the relationship between students' perceptions regarding the planning, execution and self-evaluation of learning and the selection of Moodle resources and activities. A total of 438 middle school students (grades 7-9) responded to the Inventory of Resources and Activities in Moodle Environments and to the Inventory of Self-regulated Learning in Moodle Environments. A regression analysis showed that the students' perception about the planning, execution and self-evaluation of learning predicted the selection of resources and activities pertaining to information availability and work accomplishment, but not to collaboration/interaction in all phases of work regulation.

Résumé L'autorégulation de l'apprentissage suppose une réflexion sur l'utilisation des ressources éducatives pour gérer quoi, quand, comment, avec qui et pourquoi apprendre. Cet article a pour objet le rapport entre la perception des élèves à propos de la planification, l'exécution et l'autoévaluation de l'apprentissage et la sélection de ressources et activités Moodle. Un total de 438 collégiens ont répondu à l'Inventaire de Ressources et Activités Moodle et à l'Inventaire de l'Apprentissage Autorégulé en Environnements Moodle. Une analyse de régression a montré que la perception des élèves concernant la planification, l'exécution et l'autoévaluation de l'apprentissage prédit la sélection de ressources et activités relatives à la disponibilité de l'information et à la réalisation du travail, mais non la collaboration/interaction dans toutes les phases de la régulation du travail.

Resumen La autorregulación implica reflexionar sobre la utilización de recursos educativos para hacer la gestión de qué, cuándo y cómo, con quién y por qué aprender. Este artículo pretendió investigar la relación entre la percepción de los alumnos sobre el planeamiento, la ejecución y la autoevaluación del aprendizaje, y la selección de recursos y de actividades del Moodle. Respondieron, al Inventario de Recursos y Actividades en Ambientes Moodle y al Inventario de Aprendizaje Autorregulado en Ambientes Moodle, 438 alumnos (7º al 9º años).Un análisis de regresión mostró que la percepción de los alumnos sobre el planeamiento, la ejecución y la autoevaluación del aprendizaje predice la selección de recursos y de actividades de poner a disposición informaciones y de realización del trabajo, pero no de colaboración/interacción en todas las fases de regulación del trabajo.

Cerebral Autoregulation in Patients with Unilateral Carotid Artery Stenosis / 中国医学科学院学报

To investigate cerebral autoregulation(CA)in patients with severe unilateral carotid artery stenosis by near infrared spectroscopy. Thirty patients who underwent general anesthesia in our hospital from January 2015 to February 2017 were enrolled in this study.The stenosis group included 15 patients with severe unilateral internal carotid artery stenosis,and the control group included 15 patients without carotid artery stenosis.Both groups were matched in sex and age.Cerebral tissue oxygenation index(TOI)and mean arterial pressure were recorded continuously under stable general anesthesia.The Pearson correlation coefficient()was calculated to judge the CA status. TOI was not significantly different between the stenosis side and the non-stenosis side in the stenosis group(66.52±6.50 65.23±4.50;=0.93, =0.368)or between the stenosis side in the stenosis group and the stenosis side in the control group(66.52±6.50 64.22±3.87;=1.18, =0.248).The values of stenosis side and non-stenosis side in the stenosis group were 0.36±0.12 and 0.17±0.11,respectively,and the values of the stenosis side in the stenosis group and the stenosis side of the control group were 0.36±0.12 and 0.13±0.08,respectively.In the stenosis group,5 patients had transient ischemic attack and 2 patients had a history of stroke within 3 months before operation.When an value of 0.342 was used as the judgment point of CA abnormality,the sensitivity and specificity were 0.625 and 0.909,respectively. Within the range of normal blood pressure fluctuation,cerebral blood flow is linked to blood pressure at the stenosis side in patients with severe unilateral carotid artery stenosis.

Research progress on the mechanism of the neurovascular coupling modulation / 中国脑血管病杂志

The neural activity and cognitive function require sophisticated regulation of blood flow in order to supply enough oxygen and glucose to the human brain. As a vital mechanism of cerebral blood flow autoregulation, neurovascular coupling (NVC) has characteristics of multiple channels and rapid response. Three physiological mechanisms in cortex, subcortex and postganglion were summarized, and the relationship between ischemia or hypoxia and NVC dysfunction was discussed in this article. In addition,the prospect of NVC mechanism study was addressed so as to provide new idea and target for treating cerebrovascular diseases.

Head-up and body positioning might impair dynamic cerebral autoregulation in patients with silent cerebral small vessel disease. Protocol and operational definitions / El posicionamiento elevado de cabeza y cuerpo podrían afectar la autorregulación cerebral dinámica en pacientes con enfermedad silente de pequeño vaso cerebral. Protocolo y definiciones operacionales

ABSTRACT Background: Cerebral autoregulation (CA) is the ability of intracranial vessels to maintain a constant cerebral blood flow (CBF) during changes of cerebral perfusion pressure (CPP) related to fluctuations in blood pressure, postural changes or increased metabolic demands. It has been suggested that individuals with silent cerebral small vessel disease (SVD) may have impaired CA, but information is inconclusive. We describe the protocol of a study aimed to assess the association between white matter hyperintensities (WMH) of presumed vascular origin and poor dynamic CA, and to determine the effects of head-up and body positioning in patients with this condition. Methods: Using a case-control study design, we will assess the relationship between severity of WMH and dynamic CA, measured by continuous transcranial Doppler assessment of CBF velocities in the middle cerebral arteries (MCAs) combined with beat-to-beat blood pressure monitoring. Dynamic CA will be analyzed by calculating the mean flow index as the ratio of median arterial pressure and mean flow velocities of the MCAs. Participants will be categorized as case-patients if the MRI shows moderate-to-severe WMH. For every case-patient, an age- and sex-matched healthy individual with no neuroimaging evidence of SVD will be selected as a control. Comment: This study will assess whether head-up and body positioning impairs dynamic CA in the setting of diffuse subcortical damage related to SVD, providing further evidence on the importance of CPP in maintaining the CBF. If positive, the study will provide evidence favoring the stop of aggressive hypertensive therapy or interventions promoting orthostatic hypotension to reduce the risk of further ischemic brain damage in these cases.

RESUMEN Antecedentes: La autorregulación cerebral (CA) es la capacidad de los vasos cerebrales de mantener un flujo sanguíneo constante durante cambios en la presión de perfusión cerebral (PPC) relacionados con fluctuaciones de la presión arterial, cambios posturales o aumento de las demandas metabólicas. Se ha sugerido que las personas con enfermedad de pequeño vaso cerebral pueden tener CA deteriorada, pero la información no es concluyente. Describimos el protocolo de un estudio cuyo objetivo es evaluar la asociación entre hiperintensidades de substancia blanca y CA dinámica deficiente, para determinar los efectos del posicionamiento de cabeza y cuerpo en estos pacientes. Métodos: Utilizando un diseño de caso-control, evaluaremos la relación entre la severidad de las hiperintensidades de substancia blanca y la CA dinámica, mediante Doppler transcraneal continuo de las velocidades de flujo en las arterias cerebrales medias (ACM) combinadas con monitoreo de la presión arterial. La CA dinámica se analizará calculando el índice de flujo medio y la relación entre la presión arterial media y las velocidades medias de flujo de las ACM. Los participantes se clasificarán como casos si la IRM muestra hiperintensidades de substancia blanca. Para cada caso, se seleccionará a un individuo sin evidencia de enfermedad de pequeño vaso como control. Comentario: Este estudio evaluará si el posicionamiento de la cabeza hacia arriba afecta la CA dinámica en el contexto del daño subcortical difuso relacionado con enfermedad de pequeño vaso, proporcionando evidencia adicional sobre la importancia de la PPC en el mantenimiento del flujo en estos sujetos. El estudio proporcionará evidencia sobre el uso de terapia hipertensiva agresiva o intervenciones que promueven la hipotensión ortostática para reducir el riesgo de daño cerebral isquémico.

Application of near-infrared spectroscopy in monitoring in the neurocritical care unit / 中华神经科杂志

The field of monitoring in neurocritical care has long been lacking a non-invasive monitoring technique that can be real-time evaluated at the bedside. In recent years, near-infrared spectroscopy has drawn attention in neurocritical care. The feasibility of using this technique to monitor cerebral autoregulation, perfusion, oxygenation and intracranial pressure dynamically has been noticed. We reviewed the basic principle of near-infrared spectroscopy and its application in adult neurocritical care patients, and discussed the shortcomings of this technique. More clinical researches are needed in the future to evaluate this promising monitoring technology.

Cerebral Hemodynamics in Premature Infants

Extremely low birth weight infants remain at increased risk of intraventricular hemorrhage from the fragile vascular bed of the germinal matrix; the roles of hypotension (ischemia) and reperfusion (hyperemia) in the development of intraventricular hemorrhage are still debated. Cerebrovascular pressure autoregulation protects the brain by maintaining constant cerebral blood flow despite changes in blood pressure. The ontogeny of cerebrovascular pressure autoregulation has not been well established and uncertainty remains about the optimal arterial blood pressure required to support brain perfusion. Another important aspect of premature cerebral hemodynamics is the critical closing pressure––the arterial blood pressure at which cerebral blood flow ceases. Interestingly, in premature infants, the critical closing pressure approximates the mean arterial blood pressure. Often in this unique population, cerebral blood flow occurs only during systole when the diastolic arterial blood pressure is equal to the critical closing pressure. Moreover, the diastolic closing margin, a metric of cerebral perfusion that normalizes diastolic arterial blood pressure to the critical closing pressure, may be a better measure than arterial blood pressure for defining cerebral perfusion in premature infants. Elevated diastolic closing margin has been associated with intraventricular hemorrhage. This review summarizes the current state of understanding of cerebral hemodynamics in premature infants.

Sonda uretral flexível como método alternativo para aferição invasiva da pressão intracraniana em trauma cranioencefálico induzido em coelhos / Flexible urethral catheter as alternative method to invasive measurement of intracranial pressure in induced head trauma in rabbits

O objetivo deste estudo foi utilizar a sonda uretral flexível como método alternativo para aferição da pressão intracraniana em coelhos com trauma cranioencefálico induzido pelo cateter de Fogarty 4 Fr (balão epidural) e comparar os dados obtidos com o método convencional de cateter de ventriculostomia. Foram utilizados 12 coelhos, machos, adultos, distribuídos aleatoriamente em dois grupos, denominados de G1: mensuração da PIC com cateter de ventriculostomia (n=6) e G2: mensuração com sonda uretral (n=6). Foram realizadas duas craniotomias na região parietal direita e esquerda para a implantação do cateter de ventriculostomia ou sonda uretral flexível e o balão epidural, respectivamente. A PAM, a PPC, a FC, a FR e a TR foram mensurados antes e após a craniotomia. A PIC foi avaliada após a craniotomia e a cada 10 minutos depois do preenchimento do balonete com 0,3mL de NaCl 0,9%, durante 40 minutos, e com 0,6mL, pelo mesmo período de tempo, totalizando 80 minutos. A PIC aumentou em ambos os grupos, sendo menores os valores registrados com a sonda uretral flexível. Foi possível reproduzir o aumento da PIC com o modelo experimental de TCE utilizando o cateter de Fogarty 4 Fr na região epidural e, embora haja a necessidade de outros estudos, a sonda uretral flexível demonstra ser um método alternativo de mensuração da PIC em coelhos com trauma cranioencefálico.(AU)

The aim of this study was to evaluate the use of flexible urethral catheter as an alternative method for measuring intracranial pressure in rabbits with head trauma induced by 4 F Fogarty catheter (epidural balloon) and compare the data obtained with the conventional method of ventriculostomy catheter. In this study, New Zealand rabbits were randomly distributed into two groups, G1: measuring the ICP with ventriculostomy catheter (n=6) and G2: measuring the ICP with urethral catheter (n=6). Two craniotomies were performed in the right and left parietal region for the implantation of a ventriculostomy catheter and/or flexible urethral catheter and epidural 4 Fr Fogarty arterial embolectomy catheter, respectively. MAP, CPP, HR, RF and RT values were measured before and after of the craniotomy. The ICP value was measured after craniotomy, every five minutes during 40 minutes after the balloon was inflated with 0.3 ml with NaCl and further 40 minutes after the balloon was inflated with 0.6 ml. The ICP value increased in both groups; however, the ICP values were lower in the flexible urethral catheter. The flexible urethral catheter can be used as an alternative method to measure ICP values in rabbits with head injury.(AU)

Fisiología de la perfusión medular / Physiology of spinal perfusion

Introducción: En las últimas décadas ha aumentado el interés por el estudio de la fisiología de la perfusión a nivel de la médula espinal. Muchos de los tratamientos en pacientes con lesión medular han sido basados en el paralelismo de la dinámica vascular entre el cerebro y la médula. Conocer estos aspectos así como los métodos relacionados con su monitoria resulta favorable para la adecuada intervención del paciente con lesión a nivel medular. Objetivo: Realizar una revisión en la literatura científica de los aspectos más importantes que intervienen en la perfusión de la médula espinal, los mecanismos de autorregulación y su aplicación clínica dentro del estudio de la fisiología medular. Métodos: Con las palabras claves, se realizó una revisión no sistemática en las bases de datos correspondientes a OVID, Medline/PubMed, Science Direct. Resultados y Conclusiones: El papel de la autorregulación es vital en la conservación de la integridad de la médula espinal, realizar un adecuado control de ella así como de otros factores químicos y metabólicos son determinantes en el control del flujo sanguíneo medular y minimiza el riesgo de lesión medular secundaria. Las curvas de autorregulación para el cerebro y la médula espinal son virtualmente idénticas; dentro de un rango de 60-150 mmHg.

Introduction: Over the past decades the interest in the study of the physiology of perfusion at the level of the spinal cord has increased. Many treatments in patients with spinal cord injury have been based on the parallelism of the vascular dynamics between the brain and the spinal. Knowing about these aspects and methods related to their monitoring practice is favorable for a proper intervention of the patient with spinal cord injury. Objective: To do a scientific literature review on the most important aspects involved in spinal cord perfusion, autoregulatory mechanisms and their clinical applications in the study of spinal cord physiology. Methods: Using the keywords, a non-systematic review on the OVID, Medline/PubMed and Science Direct databases, was performed. Results and Conclusion: The role of autoregulation is vital in maintaining the integrity of the spinal cord, an adequate control of it as well as other chemical and metabolic factors are important in the control of medullary blood flow and minimizes the risk of secondary spinal cord injury. The autoregulation curves for the brain and spinal cord are virtually identical, within a range of 60-150 mmHg.

The autoregulatory loop: A common mechanism of regulation of key sex determining genes in insects.

Sex determination in most insects is structured as a gene cascade, wherein a primary signal is passed through a series of sex-determining genes, culminating in a downstream double-switch known as doublesex that decides the sexual fate of the embryo. From the literature available on sex determination cascades, it becomes apparent that sex determination mechanisms have evolved rapidly. The primary signal that provides the cue to determine the sex of the embryo varies remarkably, not only among taxa, but also within taxa. Furthermore, the upstream key gene in the cascade also varies between species and even among closely related species. The order Insecta alone provides examples of astoundingly complex diversity of upstream key genes in sex determination mechanisms. Besides, unlike key upstream genes, the downstream double-switch gene is alternatively spliced to form functional sex-specific isoforms. This sex-specific splicing is conserved across insect taxa. The genes involved in the sex determination cascade such as Sex-lethal (Sxl) in Drosophila melanogaster, transformer (tra) in many other dipterans, coleopterans and hymenopterans, Feminizer (fem) in Apis mellifera, and IGF-II mRNA-binding protein (Bmimp) in Bombyx mori are reported to be regulated by an autoregulatory positive feedback loop. In this review, by taking examples from various insects, we propose the hypothesis that autoregulatory loop mechanisms of sex determination might be a general strategy. We also discuss the possible reasons for the evolution of autoregulatory loops in sex determination cascades and their impact on binary developmental choices.

Effects of different surfactant administrations on cerebral autoregulation in preterm infants with respiratory distress syndrome / 华中科技大学学报（医学）（英德文版）

To treat respiratory distress syndrome, surfactant is currently delivered via less invasive surfactant administration (LISA) or INtubation SURfactant Extubation (INSURE). The aim of this study was to compare the effect of the two delivery methods of surfactant on cerebral autoregulation. Near infrared spectroscopy monitoring was carried out to detect cerebral oxygen saturation (ScO), and the mean arterial blood pressure (MABP) was simultaneously recorded. Of 44 preterm infants included, the surfactant was administrated to 22 via LISA and 22 via INSURE. The clinical characteristics, treatments and outcomes of the infants showed no significant differences between the two groups. The correlation coefficient of ScOand MABP (r) 5 min before administration was similar in the two groups. During surfactant administration, rincreased in both groups (0.44±0.10 to 0.54±0.12 in LISA, 0.45±0.11 to 0.69±0.09 in INSURE). In the first and second 5 min after instillation, rwas not significantly different from baseline in the LISA group, but increased in the first 5 min after instillation (0.59±0.13, P=0.000 compared with the baseline in the same group) and recovered in the second 5 min after instillation (0.48±0.10, P=0.321) in the INSURE group. There were significant differences in the change rates of rbetween the two groups during and after surfactant administration. Our results suggest that cerebral autoregulation may be affected transiently by surfactant administration. The effect duration of LISA is shorter than that of INSURE (<5 min in LISA vs. 5-10 min in INSURE).

Hemodynamic factors to stabilize cerebral blood flow within limits of cerebral autoregulation / 中国神经精神疾病杂志

Objective To investigate the hemodynamic parameters to stabilize cerebral blood flow within limits of cerebral autoregualtion. Methods We assessed the flow velocity of middle cerebral artery using transcranial Doppler and recorded invasively the blood pressure simultaneously. We then analyzed the curves of cerebral blood flow autoregulation (CBFA) and calculated upper limit of autoregulation (ULA) and lower limit of autoregulation (LLA). The values of critical closing pressue (CCP) and resistance area product (RAP) were calculated according to previous theory. The relationship between CCP, RAP and MABP were analyzed. Results In the process of increasing or decreasing blood pressure, ULA and LLA of normal rats were 148.12 ± 7.49 mmHg or 62.96 ± 3.34 mmHg, respectively. When mean artery blood pressue (MABP) changed within limits of cerebral autoregulation, the cerebral blood flow velocity changed little (increasing:0.65± 0.27 cm/s/10mmHg MABP, decreasing:0.43±0.23cm/s/10 mmHg MABP), while CCP and RAP changed significantly (in?creasing: 4.60 ± 1.06 mmHg/10mmHg MABP and 0.11 ± 0.04/10 mmHg MABP, decreasing: 6.74 ± 0.59 mmHg/10 mmHg MABP and 0.09 ± 0.02/10mmHg MABP). After fixing change of blood flow velocity, CCP and RAP were correlated with MABP more remarkablely, although all blood flow velocity, CCP and RAP were significantly correlated with MABP. Conclusion Within limits of cerebral autoregulation, stable cerebral blood flow is mainly achieved by the change of CCP and RAP against blood pressure changing on normal rats, especially the increasing or de?creasing of CCP.

The clinical application and value of transcranial doppler monitoring senile cerebral blood flow autoregulation in elderly / 中国综合临床

Objective To study the clinical application and value of transcranial Doppler (TCD) monitoring senile cerebral blood flow autoregulation in elderly.Methods Two hundred cases patients with elderly hypertension and 200 cases normal eldly from May 2011 to December 2014 in the Second People 's Hospital of Fengrun District of Tangshan were chosen as hypertension group and control group.Cerebral artery peak systolic velocity,supine with a vertical artery in the brain(MCA) cerebral blood flow difference (CBFV) and X-W wave duration, cerebrovascular hemodynamic parameters of two group were monitored by TCD method and compared.Results The peak values of left vertebral artery (LVA), right vertebral artery (RVA), the left coronary artery(LCS), and right vertebral artery(RCS) of hypertension group were significantly lower than those in the control group((38.01±12.42) cm/s vs (45.21±8.95) cm/s, (35.54±13.25) cm/s vs (43.52±7.06) cm/s, (66.12±9.52) m/s vs (76.54±8.19) cm/s, (71.24± 11.25) cm/s vs (77.98± 10.74) cm/s, (55.34 ±14.52) cm/s vs (61.24±12.58) cm/s,(48.12±15.24) cm/s vs (58.46±18.85) cm/s;t=4.6821, 5.6987,6.2589,4.3671,2.2854,4.9875;P＜ 0.01).The peak Vp, the difference between the horizontal and vertical position CBFV, X-W wave duration, the parameter of DR, Cp, C, Co, Zc, Wv of arterial blood vessels (left internal carotid artery (LICA), right internal carotid artery (RICA), left middle cerebral artery (LMCA), right middle cerebral artery(RMCA) ,left anterior cerebral artery(LACA), right anterior cerebral artery(RACA), left anterior cerebral artery (LOA), right middle cerebral artery (ROA)) of hypertension group were significantly higher than those of control group((96.38±18.85) cm/s vs (83.56±13.41) cm/s, (103.04±35.42) cm/s vs (85.62±29.63) cm/s, (99.85±23.54) cm/s vs (83.12±22.67) cm/s, (102.84± 16.42) cm/s vs (86.23 ±21.34) cm/s, (85.06± 15.36) cm/s vs (73.16± 10.35) cm/s, (85.64± 15.34) cm/s vs (70.52± 18.56) cm/s, (34.85±8.74) cm/s vs (28.56±7.85) cm/s, (35.12± 11.20) cm/s vs (30.05± 6.88) cm/s, (7.22 ± ±2.54) cm/s vs (2.78± 1.87) cm/s, (23.74±5.23) cm/s vs (20.85±4.35) cm/s, (378.35±35.12) Pa? s/cm vs (314.53±36.21) Pa? s/cm, (8.16± 0.62) P/kPa vs (7.25± 0.68) P/kPa, (0.41 ± 0.05) ml/kPa vs (0.33±0.06) ml/kPa, (1.15±0.16) mL/kPa vs (0.84±0.13) ml/kPa, (346.13±42.63) dyn? s/cm5 vs (241.68±50.21) dyn? s/cm5, (21.47± 3.85) V/(cml? s) vs (11.24 ± 3.67) V/(cml? s);t =5.8954, 4.2589,4.8792,6.3985,6.3874,6.9852,5.6387,4.6892,6.0387,4.8562, 11.475,8.041,12.422, 11.820, 12.854,20.412;P＜0.01).Conclusion The function of automatic adjustment shows obvious abnormal cerebral blood flow in patients with hypertension, andthe TCD technology can response of cerebral blood flow autoregulation,which has important clinical value for diagnosis and treatment of cerebral infarction, stroke and other cardiovascular and cerebrovascular diseases.

Vagolytic atropine attenuates cerebral vasodilation response during acute orthostatic hypotension / 대한마취과학회지

BACKGROUND: Atropine is an anticholinergic drug which is commonly used in clinical practice. The effect of parasympathetic block with atropine on dynamic cerebrovascular regulation remains unclear. This study was aimed to identify effects of vagolytic atropine on cerebrovascular response during acute orthostatic hypotension in humans. METHODS: Continuous middle cerebral blood flow velocity (CBFV, transcranial Doppler) and arterial blood pressure (ABP, Finometer) were measured during a sit-to-stand procedure in 10 healthy subjects with placebo and vagolytic (10 microg/kg) doses of atropine. Cerebral vascular tone was assessed by cerebrovascular resistance (CVR = ABP / CBFV). Dynamic cerebral autoregulation was also assessed by transfer function analysis of ABP and CBFV. RESULTS: During the standing session, ABP fell to a similar extent in both groups by an average of 23 to 25 mmHg (26% to 29%). CBFV also fell in all subjects but significantly more in vagolytic atropine (-15.0 +/- 7.0 cm/s) compared with placebo (-12.0 +/- 5.8 cm/s, P < 0.05). CVR was decreased significantly in the placebo group during posture change (1.56 +/- 0.44 vs. 1.38 +/- 0.38, P < 0.05), in contrast, lesser decreased in the atropine group (1.60 +/- 0.50 vs. 1.53 +/- 0.42, P = 0.193). Transfer function coherence in the very-low-frequency range was significantly increased in the atropine group during the standing session (0.55 +/- 0.14), compared with the sitting session (0.45 +/- 0.14, P = 0.006). CONCLUSIONS: These data present that vagolytic atropine attenuates cerebral vasodilation response to acute orthostatic hypotension, suggesting the use of atropine may need care in patients with cerebrovascular disease with vagal impairment.

Two levels of the inspired oxygen fraction in propofol-anesthetized dogs with high intracranial pressure: cardiopulmonary function / Dois níveis de fração inspirada de oxigênio em cães anestesiados com propofol e com pressão intracraniana elevada: função cardiopulmonar

In the initial stage of traumatic brain injury, the use of 1.0 inspired oxygen fraction (FiO2) is indicated. However, high FiO2 has been correlated with atelectasis. Thus, the effects of FiO2 = 1.0 and FiO2 = 0.6 on the cardiopulmonary function in propofol-anesthetized dogs with high intracranial pressure (ICP) were evaluated. Eight dogs were anesthetized on two occasions, receiving, during controlled ventilation, an FiO2 = 1 (G100) or an FiO2 = 0.6 (G60). Propofol was used for induction (10mg.kg-1) followed by a continuous rate infusion (0.6mg.kg-1.minute-1). An increase in the ICP was induced by temporary obliteration of the right jugular vein (OJv) 50 minutes after induction of anesthesia. The measurement was taken twenty minutes after OJv (T0) and then at 15-minute intervals (T15 to T60). Alveolar oxygen partial pressure in G60 was lower than in G100 during the whole procedure. Alveolar-arterial oxygen gradient in G100 was greater than in G60 at T0 and at T60. No differences were observed for arterial oxygen partial pressure/inspired oxygen fraction ratio, arterial-to-alveolar oxygen pressure ratio, respiratory index, venous admixture, oxygen delivery, oxygen consumption, oxygen extraction, heart rate, mean pulmonary arterial pressure, pulmonary arterial occlusion pressure, cardiac index, stroke index and systemic vascular resistance index. In G100, mean arterial pressure at T0 was higher than at T45. In dogs with high ICP, the cardiopulmonary function was not influenced by the different FiO2 used...

No estágio inicial do trauma encefálico, o emprego de fração inspirada de oxigênio (FiO2) de 1,0 é indicado. Todavia, altas FiO2 têm sido correlacionadas com atelectasia. Assim, avaliaram-se os efeitos das FiO2 = 1.0 e FiO2 = 0.6 sobre a função cardiopulmonar em cães com pressão intracraniana (PIC) elevada e anestesiados com propofol. Oito animais foram anestesiados em duas ocasiões e receberam, durante a ventilação controlada, FiO2 = 1(G100) ou FiO2 = 0,6 (G60). Propofol foi usado para indução (10mg.kg-1) e seguido por infusão contínua (0,6mg.kg-1minuto-1). O aumento da PIC foi induzido pela obliteração temporária da veia jugular (OJv). As mensurações foram realizadas 20 minutos após OJv (T0) e em intervalos de 15 minutos (de T15 a T60). A pressão parcial de oxigênio alveolar no G60 foi menor do que no G100 durante todo o procedimento. O gradiente alveolar-arterial no G100 foi maior do que no G60, em T0 e T60. Não foram observadas diferenças para: relação pressão parcial de oxigênio/fração inspirada de oxigênio, relação arterioalveolar, índice respiratório, mistura arteriovenosa, oferta de oxigênio, consumo de oxigênio, taxa de extração de oxigênio, frequência cardíaca, pressão da artéria pulmonar média, pressão de oclusão da artéria pulmonar, índice cardíaco, índice sistólico e índice de resistência vascular sistêmica. No G100, a pressão arterial média em T0 foi maior do que em T45. Em cães com alta PIC, a função cardiopulmonar não foi influenciada pelas diferentes FiO2 empregadas...

Metacognição como processo da aprendizagem / Metacognition as learning process

A teoria da metacognição e autorregulação como facilitadora do processo de aprendizagem proposta neste artigo tem por objetivo compreender os componentes cognitivos que envolvem a aprendizagem. A pesquisa de cunho bibliográfico destaca o papel do mediador na busca de alternativas e soluções para dirimir as dificuldades presentes no ato da aprendizagem. A autorregulação torna-se presente a partir do momento que o aprendiz estabelece uma relação de mediação entre a motivação, a necessidade de aprender e a superação do desafio. Esse processo propõe mecanismos e estratégias às necessidades de aprendizagem do aprendente em forma de andaimes, visando ultrapassar obstáculos e administrar seus erros...

The theory of metacognition and self-regulation as a facilitator of the learning process proposed in this paper aims to understand the cognitive components that involve learning. The research literature highlights the nature of the mediator role in the search for alternatives and solutions to resolve the present difficulties in the act of learning. Self-regulation becomes present from the moment the learner establishes a relationship between mediation motivation, the need to learn and overcome the challenge. This process proposes mechanisms and strategies to the learning needs of the learner in the form of scaffolding, aiming to overcome obstacles and manage their errors...

The influence of positive end-expiratory pressure on cerebral blood flow and cerebrovascular autoregulation in patients with acute respiratory distress syndrome / 中华危重病急救医学

Objective To explore the influence of different positive end-expiratory pressure (PEEP) levels on cerebral blood flow (CBF) and cerebrovascular autoregulation in patients with acute respiratory distress syndrome (ARDS).Methods A prospective study was conducted.Moderate or severe ARDS patients admitted to Department of Critical Care Medicine of Jiangxi Provincial People's Hospital from January 1st,2013 to October 1st,2013 were enrolled.The changes in hemodynamics,respiratory mechanics and gas exchange under different levels of PEEP were observed.CBF velocity of middle cerebral artery (MCA) was measured using transcranial Doppler (TCD),and breath-holding index (BHI) was also calculated.Results 35 patients with ARDS were included.The oxygenation index (OI),peak inspiratory pressure (PIP),plat pressure (Pplat) and central venous pressure (CVP) were markedly elevated [OI (mmHg,1 mmHg=0.133 kPa):324.7± 117.2 vs.173.4± 95.8,t=5.913,P=0.000; PIP (cmH2O):34.7 ± 9.1 vs.26.1 ± 7.9,t=4.222,P=0.000; Pplat (cmH2O):30.5 ± 8.4 vs.22.2 ± 7.1,t=4.465,P=0.000; CVP (mmHg):12.1 ± 3.5 vs.8.8 ± 2.2,t=4.723,P=0.000] when PEEP was increased from (6.4 ± 1.0) cmH2O to (14.5-± 2.0) cmH2O (1 cmH2O=0.098 kPa).But no significant difference in the heart rate (beats/min:85.5 ± 19.1 vs.82.7 ± 17.3,t=0.643,P=0.523),mean arterial pressure (mmHg:73.5 ± 12.4 vs.76.4 ± 15.1,t=0.878,P=0.383) and CBF velocity of MCA [peak systohc flow velocity (Vmax,cm/s):91.26 ± 17.57 vs.96.64 ± 18.71,t=1.240,P=0.219; diastolic flow velocity (Vmin,cm/s) 31.54 ±7.71 vs.33.87 ±8.53,t=1.199,P=0.235; mean velocity (Vmean,cm/s) 51.19 ± 12.05 vs.54.27 ± 13.36,t=1.013,P=0.315] was found.18 patients with BHI＜0.1 at baseline demonstrated that cerebral vasomotor reactivity was poor.BHI was slightly decreased with increase in PEEP (0.78 ± 0.16 vs.0.86 ± 0.19,t=1.905,P=0.061).Conclusions Some of moderate or severe ARDS patients without central nervous system disease have independent of preexisting cerebral autoregulation impairment.However,independent of preexisting cerebral autoregulation may not further be impaired when a high PEEP was chosen.

Physiology of Normal Sleep: From Young to Old.

Human sleep, defined on the basis of electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG), is divided into rapid eye movement (REM) sleep and four stages of non–rapid eye movement (NREM) sleep. Collective monitoring and recording of physiological data during sleep is called polysomnography. Sleep which normally starts with a period of NREM alternates with REM, about 4-5 times, every night. Sleep pattern changes with increasing age. Newborns sleep for about 14-16 hours in a day of 24 hours. Although there is a wide variation among individuals, sleep of 7-8.5 hours is considered fully restorative in adults. Apart from restorative and recovery function, energy conservation could be one of the functions of sleep. The role of sleep in neurogenesis, memory consolidation and brain growth has been suggested. Though progress in medical science has vastly improved our understanding of sleep physiology, we still do not know all the functions of sleep.