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BACKGROUND: Head elevation is recommended as a tier zero measure to decrease high intracranial pressure (ICP) in neurocritical patients. However, its quantitative effects on cerebral perfusion pressure (CPP), jugular bulb oxygen saturation (SjvO2), brain tissue partial pressure of oxygen (PbtO2), and arteriovenous difference of oxygen (AVDO2) are uncertain. Our objective was to evaluate the effects of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2 among patients with acute brain injury. METHODS: We conducted a systematic review and meta-analysis on PubMed, Scopus, and Cochrane Library of studies comparing the effects of different degrees of head elevation on ICP, CPP, SjvO2, PbtO2, and AVDO2. RESULTS: A total of 25 articles were included in the systematic review. Of these, 16 provided quantitative data regarding outcomes of interest and underwent meta-analyses. The mean ICP of patients with acute brain injury was lower in group with 30° of head elevation than in the supine position group (mean difference [MD] - 5.58 mm Hg; 95% confidence interval [CI] - 6.74 to - 4.41 mm Hg; p < 0.00001). The only comparison in which a greater degree of head elevation did not significantly reduce the ICP was 45° vs. 30°. The mean CPP remained similar between 30° of head elevation and supine position (MD - 2.48 mm Hg; 95% CI - 5.69 to 0.73 mm Hg; p = 0.13). Similar findings were observed in all other comparisons. The mean SjvO2 was similar between the 30° of head elevation and supine position groups (MD 0.32%; 95% CI - 1.67% to 2.32%; p = 0.75), as was the mean PbtO2 (MD - 1.50 mm Hg; 95% CI - 4.62 to 1.62 mm Hg; p = 0.36), and the mean AVDO2 (MD 0.06 µmol/L; 95% CI - 0.20 to 0.32 µmol/L; p = 0.65).The mean ICP of patients with traumatic brain injury was also lower with 30° of head elevation when compared to the supine position. There was no difference in the mean values of mean arterial pressure, CPP, SjvO2, and PbtO2 between these groups. CONCLUSIONS: Increasing degrees of head elevation were associated, in general, with a lower ICP, whereas CPP and brain oxygenation parameters remained unchanged. The severe traumatic brain injury subanalysis found similar results.

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BACKGROUND: Numerous trials have addressed intracranial pressure (ICP) management in neurocritical care. However, identifying its harmful thresholds and controlling ICP remain challenging in terms of improving outcomes. Evidence suggests that an individualized approach is necessary for establishing tolerance limits for ICP, incorporating factors such as ICP waveform (ICPW) or pulse morphology along with additional data provided by other invasive (e.g., brain oximetry) and noninvasive monitoring (NIM) methods (e.g., transcranial Doppler, optic nerve sheath diameter ultrasound, and pupillometry). This study aims to assess current ICP monitoring practices among experienced clinicians and explore whether guidelines should incorporate ancillary parameters from NIM and ICPW in future updates. METHODS: We conducted a survey among experienced professionals involved in researching and managing patients with severe injury across low-middle-income countries (LMICs) and high-income countries (HICs). We sought their insights on ICP monitoring, particularly focusing on the impact of NIM and ICPW in various clinical scenarios. RESULTS: From October to December 2023, 109 professionals from the Americas and Europe participated in the survey, evenly distributed between LMIC and HIC. When ICP ranged from 22 to 25 mm Hg, 62.3% of respondents were open to considering additional information, such as ICPW and other monitoring techniques, before adjusting therapy intensity levels. Moreover, 77% of respondents were inclined to reassess patients with ICP in the 18-22 mm Hg range, potentially escalating therapy intensity levels with the support of ICPW and NIM. Differences emerged between LMIC and HIC participants, with more LMIC respondents preferring arterial blood pressure transducer leveling at the heart and endorsing the use of NIM techniques and ICPW as ancillary information. CONCLUSIONS: Experienced clinicians tend to personalize ICP management, emphasizing the importance of considering various monitoring techniques. ICPW and noninvasive techniques, particularly in LMIC settings, warrant further exploration and could potentially enhance individualized patient care. The study suggests updating guidelines to include these additional components for a more personalized approach to ICP management.

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SUMMARY: Intracranial aneurysm is a common cerebrovascular disease with high mortality. Neurosurgical clipping for the treatment of intracranial aneurysms can easily lead to serious postoperative complications. Studies have shown that intraoperative monitoring of the degree of cerebral ischemia is extremely important to ensure the safety of operation and improve the prognosis of patients. Aim of this study was to probe the application value of combined monitoring of intraoperative neurophysiological monitoring (IONM)-intracranial pressure (ICP)-cerebral perfusion pressure (CPP) in craniotomy clipping of intracranial aneurysms. From January 2020 to December 2022, 126 patients in our hospital with intracranial aneurysms who underwent neurosurgical clipping were randomly divided into two groups. One group received IONM monitoring during neurosurgical clipping (control group, n=63), and the other group received IONM-ICP-CPP monitoring during neurosurgical clipping (monitoring group, n=63). The aneurysm clipping and new neurological deficits at 1 day after operation were compared between the two groups. Glasgow coma scale (GCS) score and national institutes of health stroke scale (NIHSS) score were compared before operation, at 1 day and 3 months after operation. Glasgow outcome scale (GOS) and modified Rankin scale (mRS) were compared at 3 months after operation. All aneurysms were clipped completely. Rate of new neurological deficit at 1 day after operation in monitoring group was 3.17 % (2/63), which was markedly lower than that in control group of 11.11 % (7/30) (P0.05). Combined monitoring of IONM-ICP-CPP can monitor the cerebral blood flow of patients in real time during neurosurgical clipping, according to the monitoring results, timely intervention measures can improve the consciousness state of patients in early postoperative period and reduce the occurrence of early postoperative neurological deficits.

El aneurisma intracraneal es una enfermedad cerebrovascular común con alta mortalidad. El clipaje neuroquirúrgico para el tratamiento de aneurismas intracraneales puede provocar complicaciones posoperatorias graves. Los estudios han demostrado que la monitorización intraoperatoria del grado de isquemia cerebral es extremadamente importante para garantizar la seguridad de la operación y mejorar el pronóstico de los pacientes. El objetivo de este estudio fue probar el valor de la aplicación de la monitorización combinada de la monitorización neurofisiológica intraoperatoria (IONM), la presión intracraneal (PIC) y la presión de perfusión cerebral (CPP) en el clipaje de craneotomía de aneurismas intracraneales. Desde enero de 2020 hasta diciembre de 2022, 126 pacientes de nuestro hospital con aneurismas intracraneales que se sometieron a clipaje neuroquirúrgico se dividieron aleatoriamente en dos grupos. Un grupo recibió monitorización IONM durante el clipaje neuroquirúrgico (grupo de control, n=63) y el otro grupo recibió monitorización IONM-ICP-CPP durante el clipaje neuroquirúrgico (grupo de monitorización, n=63). Se compararon entre los dos grupos el recorte del aneurisma y los nuevos déficits neurológicos un día después de la operación. La puntuación de la escala de coma de Glasgow (GCS) y la puntuación de la escala de accidentes cerebrovasculares de los institutos nacionales de salud (NIHSS) se compararon antes de la operación, 1 día y 3 meses después de la operación. La escala de resultados de Glasgow (GOS) y la escala de Rankin modificada (mRS) se compararon 3 meses después de la operación. Todos los aneurismas fueron cortados por completo. La tasa de nuevo déficit neurológico 1 día después de la operación en el grupo de seguimiento fue del 3,17 % (2/63), que fue notablemente inferior a la del grupo de control del 11,11 % (7/30) (P 0,05). La monitorización combinada de IONM-ICP-CPP puede controlar el flujo sanguíneo cerebral de los pacientes en tiempo real durante el corte neuroquirúrgico; de acuerdo con los resultados de la monitorización, las medidas de intervención oportunas pueden mejorar el estado de conciencia de los pacientes en el período postoperatorio temprano y reducir la aparición de problemas postoperatorios tempranos y déficits neurológicos.

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Cerebral perfusion pressure (CPP) is calculated as the difference between mean arterial blood pressure and mean intracranial pressure, being commonly applied in neurocritical care. This commentary discusses recent physiological advances in knowledge as well as bedside practice issues that in combination indicate considering CPP under this perspective may lead to inaccurate assumptions and potentially misleading decision making.

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BACKGROUND: Critical closing pressure (CrCP) and resistance-area product (RAP) have been conceived as compasses to optimize cerebral perfusion pressure (CPP) and monitor cerebrovascular resistance, respectively. However, for patients with acute brain injury (ABI), the impact of intracranial pressure (ICP) variability on these variables is poorly understood. The present study evaluates the effects of a controlled ICP variation on CrCP and RAP among patients with ABI. METHODS: Consecutive neurocritical patients with ICP monitoring were included along with transcranial Doppler and invasive arterial blood pressure monitoring. Internal jugular veins compression was performed for 60 s for the elevation of intracranial blood volume and ICP. Patients were separated in groups according to previous intracranial hypertension severity, with either no skull opening (Sk1), neurosurgical mass lesions evacuation, or decompressive craniectomy (DC) (patients with DC [Sk3]). RESULTS: Among 98 included patients, the correlation between change (Δ) in ICP and the corresponding ΔCrCP was strong (group Sk1 r = 0.643 [p = 0.0007], group with neurosurgical mass lesions evacuation r = 0.732 [p < 0.0001], and group Sk3 r = 0.580 [p = 0.003], respectively). Patients from group Sk3 presented a significantly higher ΔRAP (p = 0.005); however, for this group, a higher response in mean arterial pressure (change in mean arterial pressure p = 0.034) was observed. Exclusively, group Sk1 disclosed reduction in ICP before internal jugular veins compression withholding. CONCLUSIONS: This study elucidates that CrCP reliably changes in accordance with ICP, being useful to indicate ideal CPP in neurocritical settings. In the early days after DC, cerebrovascular resistance seems to remain elevated, despite exacerbated arterial blood pressure responses in efforts to maintain CPP stable. Patients with ABI with no need of surgical procedures appear to remain with more effective ICP compensatory mechanisms when compared with those who underwent neurosurgical interventions.

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Traumatic brain injury (TBI) is a worldwide public health concern given its significant morbidity and mortality, years of potential life lost, reduced quality of life and elevated healthcare costs. The primary injury occurs at the moment of impact, but secondary injuries might develop as a result of brain hemodynamic abnormalities, hypoxia, and hypotension. The cerebral edema and hemorrhage of the injured tissues causes a decrease in cerebral perfusion pressure (CPP), which leads to higher risk of cerebral ischemia, herniation and death. In this setting, our role as physicians is to minimize damage by the optimization of the CPP and therefore to reduce mortality and improve neurological outcomes. Performing a transcranial doppler ultrasound (TCD) allows to estimate cerebral blood flow velocities and identify states of low flow and high resistance. We propose to include TCD as an initial assessment and further monitoring tool for resuscitation guidance in patients with severe TBI. We present an Ultrasound-Guided Cardio-cerebral Resuscitation (UGCeR) protocol in Patients with Severe TBI.

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Cerebral perfusion pressure (CPP) is normally expressed by the difference between mean arterial blood pressure (MAP) and intracranial pressure (ICP) but comparison of the separate contributions of MAP and ICP to human cerebral blood flow autoregulation has not been reported. In patients with acute brain injury (ABI), internal jugular vein compression (IJVC) was performed for 60 s. Dynamic cerebral autoregulation (dCA) was assessed in recordings of middle cerebral artery blood velocity (MCAv, transcranial Doppler), and invasive measurements of MAP and ICP. Patients were separated according to injury severity as having whole/undamaged skull, large fractures, or craniotomies, or following decompressive craniectomy. Glasgow coma score was not different for the three groups. IJVC induced changes in MCAv, MAP, ICP, and CPP in all three groups. The MCAv response to step changes in MAP and ICP expressed the dCA response to these two inputs and was quantified with the autoregulation index (ARI). In 85 patients, ARI was lower for the ICP input as compared with the MAP input (2.25 ± 2.46 vs. 3.39 ± 2.28; P < 0.0001), and particularly depressed in the decompressive craniectomy (DC) group (n = 24, 0.35 ± 0.62 vs. 2.21 ± 1.96; P < 0.0005). In patients with ABI, the dCA response to changes in ICP is less efficient than corresponding responses to MAP changes. These results should be taken into consideration in studies aimed to optimize dCA by manipulation of CPP in neurocritical patients.

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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.

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Objetivo: Describir el comportamiento de la presión de perfusión ocular en sujetos sin enfermedad ocular. Métodos: Se realizó un estudio descriptivo transversal con sujetos sin enfermedad ocular de la consulta externa de Oftalmología del Hospital Universitario "General Calixto García", entre enero y diciembre de 2019. Resultados: La mediana de presión intraocular del ojo derecho osciló entre 13,0-16,0 mmHg, y del ojo izquierdo entre 13,0-15,5 mmHg, durante todo el estudio. El valor máximo para ambos ojos se obtuvo a las 6:00 a. m. (madrugada). La mediana de presión arterial sistólica osciló entre 129,0-138,5 mmHg, y de diastólica entre 79,5-81,5 mmHg. El valor mínimo de presión arterial diastólica fue 53 mmHg a las 6:00 a. m. La mediana de presión de perfusión ocular del ojo derecho osciló entre 46,4 mmHg (12:00 a. m.) y 50,8 mmHg; y del ojo izquierdo entre 47,3 mmHg (6:00 a. m.) y 51,9 mmHg. El valor mínimo específico de presión de perfusión ocular fue 35 mmHg para ambos ojos, a las 6:00 a. m. Conclusiones: La hipertensión arterial es el antecedente patológico personal más frecuente en la población estudiada y en ocasiones se producen cifras fuera de la normalidad, tanto elevadas como disminuidas, capaces de afectar la presión de perfusión ocular, sobre todo la diastólica baja. Sin embargo, las presiones de perfusión ocular se mantuvieron normales, probablemente, por mecanismos de autorregulación individuales(AU)

Objective: To describe the behavior of ocular perfusion pressure in subjects without ocular disease. Methods: A cross-sectional descriptive study was performed with subjects without ocular disease from the Ophthalmology outpatient clinic of the University Hospital "General Calixto García", between January and December 2019. Results: The median intraocular pressure of the right eye ranged between 13.0-16.0 mmHg, and of the left eye between 13.0-15.5 mmHg, throughout the study. The maximum value for both eyes was obtained at 6:00 a. m. (early morning). The median systolic blood pressure ranged from 129.0-138.5 mmHg, and diastolic from 79.5-81.5 mmHg. The minimum diastolic blood pressure value was 53 mmHg at 6:00 a.m. The median ocular perfusion pressure of the right eye ranged from 46.4 mmHg (12:00 a.m.) to 50.8 mmHg; and of the left eye from 47.3 mmHg (6:00 a.m.) to 51.9 mmHg. The minimum specific ocular perfusion pressure value was 35 mmHg for both eyes, at 6:00 a.m. Conclusions: Arterial hypertension is the most frequent personal pathologic antecedent in the population studied, and both elevated and decreased out-of-normal figures capable of affecting ocular perfusion pressure, especially low diastolic, occasionally occur. However, ocular perfusion pressures remained normal, probably due to individual autoregulatory mechanisms(AU)

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RESUMEN La ecografía Doppler transcraneal es un método no invasivo que permite una adecuada monitorización de los diferentes parámetros que ayudan a definir conductas para los médicos intensivistas, sin embargo, su utilización no está generalizada entre las comunidades médicas que atienden niños con afecciones neurocríticas. Es propósito de los autores, actualizar el tema en estudio y presentar su experiencia en población pediátrica. Las indicaciones de este método provienen de investigaciones en pacientes adultos, se necesitan estudios multicéntricos en diferentes contextos clínicos para poder establecer esta técnica como un método de diagnóstico confiable en pacientes pediátricos. Concluimos que utilizar el Doppler transcraneal como prueba auxiliar en la estimación de la presión intracraneal y presión de perfusión cerebral, proporciona adoptar recursos terapéuticos frente al paciente lo más acertados posibles y brinda la posibilidad de hacer un seguimiento y evaluación de los tratamientos a pie de cama de forma mínimamente invasiva.

ABSTRACT Transcranial Doppler ultrasound is a non-invasive method that allows adequate monitoring of the different parameters that help define behaviors for intensivist physicians ; however, its use is not widespread among the medical communities that care for children with neurocritical conditions. It is the purpose of the authors to update the topic under study and present their experience with pediatric populations. The indications for this method come from research in adult patients . Multicenter studies in different clinical contexts are needed to establish this technique as a reliable diagnostic method in pediatric patients. We conclude that using transcranial Doppler as an auxiliary test in the estimation of intracranial pressure and cerebral perfusion pressure, provides the implementation of therapeutic resources in front of the patient as accurate as possible and offers the possibility of monitoring and evaluating bedside treatments in a minimally invasive way.