ICP wave morphology as a screening test to exclude intracranial hypertension in brain-injured patients: a non-invasive perspective.

Intracranial hypertension (IH) is a life-threating condition especially for the brain injured patient. In such cases, an external ventricular drain (EVD) or an intraparenchymal bolt are the conventional gold standard for intracranial pressure (ICPi) monitoring. However, these techniques have several limitations. Therefore, identifying an ideal screening method for IH is important to avoid the unnecessary placement of ICPi and expedite its introduction in patients who require it. A potential screening tool is the ICP wave morphology (ICPW) which changes according to the intracranial volume-pressure curve. Specifically, the P2/P1 ratio of the ICPW has shown promise as a triage test to indicate normal ICP. In this study, we propose evaluating the noninvasive ICPW (nICPW-B4C sensor) as a screening method for ICPi monitoring in patients with moderate to high probability of IH. This is a retrospective analysis of a prospective, multicenter study that recruited adult patients requiring ICPi monitoring from both Federal University of São Paulo and University of São Paulo Medical School Hospitals. ICPi values and the nICPW parameters were obtained from both the invasive and the noninvasive methods simultaneously 5 min after the closure of the EVD drainage. ICP assessment was performed using a catheter inserted into the ventricle and connected to a pressure transducer and a drainage system. The B4C sensor was positioned on the patient's scalp without the need for trichotomy, surgical incision or trepanation, and the morphology of the ICP waves acquired through a strain sensor that can detect and monitor skull bone deformations caused by changes in ICP. All patients were monitored using this noninvasive system for at least 10 min per session. The area under the curve (AUC) was used to describe discriminatory power of the P2/P1 ratio for IH, with emphasis in the Negative Predictive value (NPV), based on the Youden index, and the negative likelihood ratio [LR-]. Recruitment occurred from August 2017 to March 2020. A total of 69 patients fulfilled inclusion and exclusion criteria in the two centers and a total of 111 monitorizations were performed. The mean P2/P1 ratio value in the sample was 1.12. The mean P2/P1 value in the no IH population was 1.01 meanwhile in the IH population was 1.32 (p < 0.01). The best Youden index for the mean P2/P1 ratio was with a cut-off value of 1.13 showing a sensitivity of 93%, specificity of 60%, and a NPV of 97%, as well as an AUC of 0.83 to predict IH. With the 1.13 cut-off value for P2/P1 ratio, the LR- for IH was 0.11, corresponding to a strong performance in ruling out the condition (IH), with an approximate 45% reduction in condition probability after a negative test (ICPW). To conclude, the P2/P1 ratio of the noninvasive ICP waveform showed in this study a high Negative Predictive Value and Likelihood Ratio in different acute neurological conditions to rule out IH. As a result, this parameter may be beneficial in situations where invasive methods are not feasible or unavailable and to screen high-risk patients for potential invasive ICP monitoring.Trial registration: At clinicaltrials.gov under numbers NCT05121155 (Registered 16 November 2021-retrospectively registered) and NCT03144219 (Registered 30 September 2022-retrospectively registered).

Noninvasive intracranial pressure monitoring throughout brain compliance guiding a ventriculoperitoneal shunt replacement in hydrocephalus-case report.

INTRODUCTION: Ventriculoperitoneal (VP) shunt is the primary therapy for hydrocephalus in children; however, this technique is amenable to malfunctions, which could be detected through an assessment of clinical signs and imaging results. Furthermore, early detection can prevent patient deterioration and guide clinical and surgical treatment. CASE PRESENTATION: A 5-year-old female with a premedical history of neonatal IVH, secondary hydrocephalus, multiple VP shunts revisions, and slit ventricle syndrome was evaluated using a noninvasive intracranial pressure monitor device at the early stages of the clinical symptoms, evidencing increased intracranial pressure and poor brain compliance. Serial MRI images demonstrated a slight ventricular enlargement, leading to the use of a gravitational VP shunt, promoting progressive improvement. On the follow-up visits, we used the noninvasive ICP monitoring device to guide the shunt adjustments until symptom resolution. Furthermore, the patient has been asymptomatic for the past 3 years without requiring new shunt revisions. DISCUSSION: Slit ventricle syndrome and VP shunt dysfunctions are challenging diagnoses for the neurosurgeon. The noninvasive intracranial monitoring has allowed a closer follow-up assisting early assessment of brain compliance changes related to a patient's symptomatology. Furthermore, this technique has high sensitivity and specificity in detecting alterations in the intracranial pressure, serving as a guide for the adjustments of programmable VP shunts, which may improve the patient's quality of life. CONCLUSION: Noninvasive ICP monitoring may lead to a less invasive assessment of patients with slit ventricle syndrome and could be used as a guide for adjustments of programmable shunts.

Noninvasive intracranial pressure waveforms for estimation of intracranial hypertension and outcome prediction in acute brain-injured patients.

Analysis of intracranial pressure waveforms (ICPW) provides information on intracranial compliance. We aimed to assess the correlation between noninvasive ICPW (NICPW) and invasively measured intracranial pressure (ICP) and to assess the NICPW prognostic value in this population. In this cohort, acute brain-injured (ABI) patients were included within 5 days from admission in six Intensive Care Units. Mean ICP (mICP) values and the P2/P1 ratio derived from NICPW were analyzed and correlated with outcome, which was defined as: (a) early death (ED); survivors on spontaneous breathing (SB) or survivors on mechanical ventilation (MV) at 7 days from inclusion. Intracranial hypertension (IHT) was defined by ICP > 20 mmHg. A total of 72 patients were included (mean age 39, 68% TBI). mICP and P2/P1 values were significantly correlated (r = 0.49, p < 0.001). P2/P1 ratio was significantly higher in patients with IHT and had an area under the receiving operator curve (AUROC) to predict IHT of 0.88 (95% CI 0.78-0.98). mICP and P2/P1 ratio was also significantly higher for ED group (n = 10) than the other groups. The AUROC of P2/P1 to predict ED was 0.71 [95% CI 0.53-0.87], and the threshold P2/P1 > 1.2 showed a sensitivity of 60% [95% CI 31-83%] and a specificity of 69% [95% CI 57-79%]. Similar results were observed when decompressive craniectomy patients were excluded. In this study, P2/P1 derived from noninvasive ICPW assessment was well correlated with IHT. This information seems to be as associated with ABI patients outcomes as ICP.Trial registration: NCT03144219, Registered 01 May 2017 Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT03144219 .

Comparison of Waveforms Between Noninvasive and Invasive Monitoring of Intracranial Pressure.

Intracranial pressure (ICP) is an important invasive monitoring parameter in management of patients with acute brain injury and compromised compliance. This study aimed to compare waveforms obtained from standard ICP monitoring and noninvasive ICP monitoring (nICP) methods.We analyzed continuous arterial blood pressure (ABP) waves, ICP (with standard monitoring), and nICP recorded simultaneously. All signal recordings were sliced into data chunks, each 1 min in duration, and from the mean pulse, we determined the time to peak (Tp) and the ratio between tidal and percussion waves (P2/P1). We also calculated the Isomap projection of the pulses into a bidimensional space-K1 and K2. The defined nICP and ICP parameters were compared using a unilateral Wilcoxon-Mann-Whitney test. The Pearson correlation coefficient and normalized mutual information were used to verify the association between parameters.In total, 1504 min of monitoring from ten patients were studied. Nine of the patients were male. The mean age of the patients was 58.4 ± 10.4 years, and they had an initial Glasgow Coma Scale of 9 ± 4, a mean Simplified Acute Physiology Score (SAPS II) of 45.6, and an intensive care unit stay of 44 ± 45 days. With the exception of Tp, all parameters showed a weak linear association but presented a strong nonlinear association.Mutual information analysis and a bigger sample size would be helpful to build more refined models and to improve understanding of the waveform relationships.

Prediction of intracranial hypertension through noninvasive intracranial pressure waveform analysis in pediatric hydrocephalus.

PURPOSE: The purpose of this study is to evaluate a noninvasive device to assess intracranial pressure wave form in children with hydrocephalus. METHODS: A prospective and non-experimental descriptive-analytic study was performed. Fifty-six patients were enrolled in this study. They were divided in four groups: group A, children with clinically compensated hydrocephalus; B, surgically treated hydrocephalus; C, patients with acute intracranial hypertension due to hydrocephalus; and D, children without neurological disease (control). Data were collected through the installation of an extracranial deformation sensor, coupled to the children's scalp, which allowed registration of noninvasive intracranial pressure curves. Parameters obtained were analyzed: P2/P1 ratio, "classification P1 and P2 and P1 slope. RESULTS: P2/P1 index and "classification of P1 and P2" had a sensitivity of 80% and specificity of 100% for predicting intracranial hypertension. "P1 slope" presented no statistical difference. CONCLUSION: This study showed a useful and noninvasive method for monitoring intracranial pressure, which was able to indicate the intracranial hypertension in children with hydrocephalus and, thus, should be further investigated for clinical applications.

Characterization of Intracranial Pressure Behavior in Chronic Epileptic Animals: A Preliminary Study.

Intracranial pressure (ICP) is a major neurological parameter in animals and humans. ICP is a function of the relationship between the contents of the cranium (brain parenchyma, cerebrospinal fluid, and blood) and the volume of the skull. Increased ICP can cause serious physiological effects or even death in patients who do not quickly receive proper care, which includes ICP monitoring. Epilepsies are a set of central nervous system disorders resulting from abnormal and excessive neuronal discharges, usually associated with hypersynchronism and/or hyperexcitability. Temporal lobe epilepsy (TLE) is one of the most common forms of epilepsy and is also refractory to medication. ICP characteristics of subjects with epilepsy have not been elucidated because there are few studies associating these two important neurological factors. In this work, an invasive (ICPi) and the new minimally invasive (ICPmi) methods were used to evaluate ICP features in rats with chronic epilepsy, induced by the experimental model of pilocarpine, capable of generating the main features of human TLE in these animals.

Characterization of ICP Behavior in an Experimental Model of Hemorrhagic Stroke in Rats.

Intracranial pressure (ICP) monitoring is sometimes required in clinical pictures of stroke, as extensive intraparenchymal hematomas and intracranial bleeding may severely increase ICP, which can lead to irreversible conditions, such as dementia and cognitive derangement. ICP monitoring has been accepted as a procedure for the safe diagnosis of increased ICP, and for the treatment of intracranial hypertension in some diseases. In this work, we evaluated ICP behavior during the induction of an experimental model of autologous blood injection in rats, simulating a hemorrhagic stroke. Rats were subjected to stereotactic surgery for the implantation of a unilateral cannula into the left striatal region of the brain. Autologous blood was infused into the left striatal region with an automatic microinfusion pump. ICP monitoring was performed throughout the procedure of hemorrhagic stroke induction. Analyses consisted of short-time Fourier transform for ICP before and after stroke induction and the histological processing of the animals' brains. Short-time Fourier transform analysis demonstrated oscillations in the ICP frequency components throughout time after the microinjections compared with data before them. Histological analysis revealed neuropathological changes in the striatum in all microinjected animals.

Age as a predictive factor for reduced intracranial compliance in patients with headache.

BACKGROUND: Increased intracranial pressure (ICP) consists of a set of signs and symptoms related to changes in intracranial compliance (ICC) and ICP. OBJECTIVE: This study presents a retrospective analysis of patients who underwent non-invasive monitoring of ICC based on complaints of headache, correlating decreased brain compliance and increased intracranial pressure. METHODS: Noninvasive ICC monitoring was performed using a Brain4care device, which contains a strain gauge and a recorder connected to a mechanical device that touches the scalp surface in the frontoparietal area lateral to the sagittal suture. This tool monitors the ICP by identifying small changes in skull measurements that are caused by pressure variations, i.e., skull deformation is associated with the detection of changes in mean ICP. A clinical evaluation of 32 patients with complaints of headache occurred from the analysis of their medical records. RESULTS: Of the 32 patients initially chosen, it was possible to complete the analysis of 18 due to the availability of data in the medical records. From the non-invasive monitoring of the ICC, the following data were collected: time-to-peak, P2/P1 ratio, age, and gender. From the statistical analysis of age and P2/P1 ratio, it was noted that as age increases, ICC tends to decrease regardless of sex (p < 0.05). CONCLUSION: This study concluded that there is a correlation between changes in intracranial compliance and headache complaints in outpatients. There was also a relationship between age and decreased intracranial compliance but without a specific pain pattern.

ANTECEDENTES: O aumento da pressão intracraniana (PIC) consiste em um conjunto de sinais e sintomas relacionados a mudanças na complacência intracraniana (CIC) e na PIC. OBJETIVO: Este estudo apresenta uma análise retrospectiva de pacientes que foram submetidos ao monitoramento não invasivo da CIC com base em queixas de cefaleia, correlacionando a diminuição da complacência cerebral e o aumento da pressão intracraniana. MéTODOS: O monitoramento não invasivo da CIC foi realizado utilizando um dispositivo Brain4Care, que contém um medidor de tensão e um gravador conectado a um dispositivo mecânico que toca a superfície do couro cabeludo na área frontoparietal lateral à sutura sagital. Esta ferramenta monitora a PIC identificando pequenas alterações nas medidas do crânio que são causadas por variações de pressão, ou seja, a deformação do crânio está associada à detecção de alterações na PIC média. Uma avaliação clínica de 32 pacientes com queixas de cefaleia ocorreu a partir da análise de seus prontuários médicos. RESULTADOS: Dos 32 pacientes inicialmente escolhidos, foi possível concluir a análise de 18 devido à disponibilidade de dados nos prontuários médicos. A partir do monitoramento não invasivo da CIC, foram coletados os seguintes dados: time-to-peak, relação P2/P1, idade e sexo. Da análise estatística de idade e relação P2/P1, observou-se que à medida em que a idade aumenta, a CIC tende a diminuir independentemente do sexo (p < 0,05). CONCLUSãO: Este estudo concluiu que existe uma correlação entre as mudanças na CIC e a queixa de cefaleia em pacientes ambulatoriais. Houve também uma relação entre idade e diminuição da CIC, mas sem um padrão de dor específico.

Intracranial compliance and volumetry in patients with traumatic brain injury.

Background: Cerebral edema (CE) and intracranial hypertension (IHT) are complications of numerous neurological pathologies. However, the study of CE and noninvasive methods to predict IHT remains rudimentary. This study aims to identify in traumatic brain injury (TBI) patients the relationship between the volume of the lateral ventricles and the parameters of the noninvasive intracranial pressure waveform (nICPW). Methods: This is an analytical, descriptive, and cross-sectional study with nonsurgical TBI patients. The monitoring of nICPW was performed with a mechanical strain gauge, and the volumetry of the lateral ventricles was calculated using the free 3D Slicer software, both during the acute phase of the injury. The linear model of fixed and random mixed effects with Gamma was used to calculate the influence of nICPW parameters (P2/P1 and time-to-peak [TTP]) values on volumetry. Results: Considering only the fixed effects of the sample, there was P = 0.727 (95% CI [-0.653; 0.364]) for the relationship between P2/P1 and volumetry and 0.727 (95% CI [-1.657; 1.305]) for TTP and volumetry. Considering the fixed and random effects, there was P = 8.5e-10 (95% CI [-0.759; 0.355]) for the relationship between P2/P1 and volumetry and 8.5e-10 (95% CI [-2.001; 0.274]) for TTP and volumetry. Conclusion: The present study with TBI patients found association between nICPW parameters and the volume of the lateral ventricles in the 1st days after injury.

Intracranial pressure waveform in patients with essential hypertension.

Background: There is a strong association between hypertension and cerebrovascular diseases, but most of the mechanistic bases to justify this correlation remains misunderstood. Objective: To evaluate intracranial pressure waveform in long-term essential hypertensive patients with a non-invasive device, brain4care (b4c). Methods: Cross-sectional study in patients with hypertension. Office blood pressure was measured with an automatic oscillometric device. Intracranial pressure evaluation was acquired through a strain sensor that could detect and monitor nanometric skull bone displacements for each cardiac cycle. Under normal physiological conditions, P1 is greater than P2, and the normal P2/P1 ratio is <1. Time to peak (TTP) is the measurement in seconds of the beginning of waveform inscription until P1 and normal values are <0.20 s. The cut-off points ≥1.2 and ≥0.25 s were used to define intracranial hypertension (ICHT). Results: 391 consecutive patients were evaluated (75% female, mean age 64.3 ± 12.0 years). Mean value of P2/P1 ratio was 1.18 ± 0.25 and TTP 0.18 ± 0.63 s The obtained P2/P1 ratios were divided in three categories according to results of previous studies of normalcy (<1.0), intracranial compliance disturbance (1.0-1.19) and ICHT (≥1.2). Normal intracranial pressure was observed in 21.7% of patients, intracranial compliance disturbance in 32.7% and intracranial hypertension in 45.6%. Females showed a higher prevalence of ICHT (50.3%). Conclusion: The prevalence of 45.6% intra-cranial hypertension in patients with long-term hypertension, particularly in women, and in those over 65 years old, emphasizes the importance of evaluate intracranial pressure behaviour in these patients and raise a question concerning the real ability of cerebral autoregulation and vascular barriers to protect the brain.

Astrocytoma Mimicking Herpetic Meningoencephalitis: The Role of Non-Invasive Multimodal Monitoring in Neurointensivism.

Neuromonitoring is a critical tool for emergency rooms and intensive care units to promptly identify and treat brain injuries. The case report of a patient with status epilepticus necessitating orotracheal intubation and intravenous lorazepam administration is presented. A pattern of epileptiform activity was detected in the left temporal region, and intravenous Acyclovir was administered based on the diagnostic hypothesis of herpetic meningoencephalitis. The neurointensivist opted for multimodal non-invasive bedside neuromonitoring due to the complexity of the patient's condition. A Brain4care (B4C) non-invasive intracranial compliance monitor was utilized alongside the assessment of an optic nerve sheath diameter (ONSD) and transcranial Doppler (TCD). Based on the collected data, a diagnosis of intracranial hypertension (ICH) was made and a treatment plan was developed. After the neurosurgery team's evaluation, a stereotaxic biopsy of the temporal lesion revealed a grade 2 diffuse astrocytoma, and an urgent total resection was performed. Research suggests that monitoring patients in a dedicated neurologic intensive care unit (Neuro ICU) can lead to improved outcomes and shorter hospital stays. In addition to being useful for patients with a primary brain injury, neuromonitoring may also be advantageous for those at risk of cerebral hemodynamic impairment. Lastly, it is essential to note that neuromonitoring technologies are non-invasive, less expensive, safe, and bedside-accessible approaches with significant diagnostic and monitoring potential for patients at risk of brain abnormalities. Multimodal neuromonitoring is a vital tool in critical care units for the identification and management of acute brain trauma as well as for patients at risk of cerebral hemodynamic impairment.

Relationship between dialysis quality and brain compliance in patients with end-stage renal disease (ESRD): a cross-sectional study.

BACKGROUND: The high number of patients with end-stage kidney disease (ESRD) on hemodialysis makes it necessary to conduct studies aimed at improving their quality of life. OBJECTIVES: To evaluate brain compliance, using the Brain4care method for intracranial pressure (ICP) monitoring, among patients with ESRD before and at the end of the hemodialysis session, and to correlate ICP with the dialysis quality index (Kt/V). DESIGN AND SETTING: Cross-sectional study conducted at a renal replacement therapy center in Brazil. METHODS: Sixty volunteers who were undergoing hemodialysis three times a week were included in this study. Brain compliance was assessed before and after hemodialysis using the noninvasive Brain4care method and intracranial pressure wave morphology was analyzed. RESULTS: Among these 60 ESRD volunteers, 17 (28%) presented altered brain compliance before hemodialysis. After hemodialysis, 12 (20%) exhibited normalization of brain compliance. Moreover, 10 (83%) of the 12 patients whose post-dialysis brain compliance became normalized were seen to present good-quality dialysis, as confirmed by Kt/V > 1.2. CONCLUSIONS: It can be suggested that changes to cerebral compliance in individuals with ESRD occur frequently and that a good-quality hemodialysis session (Kt/V > 1.2) may be effective for normalizing the patient's cerebral compliance.

From disease to noninvasive intracranial monitoring.

Professor Sérgio Mascarenhas was a Brazilian researcher with a vast legacy. His work paved the way for new research possibilities by consolidating the use of innovation and transdisciplinary science. In Medicine, he proposed changes to what had previously been well-accepted concepts, and his contributions have influenced medical practices. Although many authors consider intracranial pressure (ICP) as an unrivaled variable for monitoring and diagnosis of many diseases, its clinical applicability is still the subject of debate in the literature because of the difficulty in standardizing protocols. Mascarenhas's research and the creation of a device for noninvasive monitoring of intracranial compliance are discussed and are shown to have led to the creation of Brain4care, a start-up, and a new perspective on the debate on ICP monitoring.

Case Report: Untreatable Headache in a Child With Ventriculoperitoneal Shunt Managed by Use of New Non-invasive Intracranial Pressure Waveform.

brain4care, a new Food and Drug Administration (FDA)-cleared non-invasive sensor that monitors intracranial pressure waveforms, was used in a 13-year-old girl who presented with untreatable headaches. The patient had a history of craniopharyngioma resection and a ventriculoperitoneal shunt placement 7 years prior to the use of the device. Secondary obstructive hydrocephalus was also a present factor in the case. The hypothesis was that due to the hydrocephalus, the child presented chronic headaches and needed constant readjustment into the ventriculoperitoneal shunt to regulate the cerebrospinal fluid inside her ventricles in order to control the patient's intracranial pressure (ICP). The device was chosen considering the risks to submit a patient into the regular invasive method to measure ICP. It was identified that the device could also indicate altered intracranial compliance due to the ratio between the P1 and P2 amplitudes (P2/P1 ratio > 1).

The historic evolution of intracranial pressure and cerebrospinal fluid pulse pressure concepts: Two centuries of challenges.

BACKGROUND: There is a consensus on the importance of monitoring intracranial pressure (ICP) during neurosurgery, and this monitoring reduces mortality during procedures. Current knowledge of ICP and cerebrospinal fluid pulse pressure has been built thanks to more than two centuries of research on brain dynamics. METHODS: Articles and books were selected using the descriptors "ICP," "cerebrospinal fluid pulse," "monitoring," "Monro-Kellie doctrine," and "ICP waveform" in electronic databases PubMed, Lilacs, Science Direct, and EMBASE. RESULTS: Several anatomists and physiologists have helped clarify the patterns of intracranial volumes under normal and pathological conditions. Monro-Kellie doctrine was an important step in a story that is reconstructed in this article. Through documentary research, we report the contribution of important medical figures, such as Monro, Kellie, Abercrombie, Burrows, Cushing, Langfitt, Marmarou, and other physiologists and anatomists who left their marks on the history of Medicine. CONCLUSION: Understanding intracranial dynamics is an unfinished historical construction. Current knowledge is the result of two centuries of research that began with the investigations of Alexander Monro secundus.

Intracranial Compliance Concepts and Assessment: A Scoping Review.

Background: Intracranial compliance (ICC) has been studied to complement the interpretation of intracranial pressure (ICP) in neurocritical care and help predict brain function deterioration. It has been reported that ICC is related to maintaining ICP stability despite changes in intracranial volume. However, this has not been properly translated to clinical practice. Therefore, the main objective of this scoping review was to map the key concepts of ICC in the literature. This review also aimed to characterize the relationship between ICC and ICP and systematically describe the outcomes used to assess ICC using both invasive and non-invasive measurement methods. Methods: This review included the following: (1) population: animal and humans, (2) concept of compliance or its inverse "elastance," and (3) context: neurocritical care. Therefore, literature searches without a time frame were conducted on several databases using a combination of keywords and descriptors. Results and Discussion: 43,339 articles were identified, and 297 studies fulfilled the inclusion criteria after the selection process. One hundred and five studies defined ICC. The concept was organized into three main components: physiological definition, clinical interpretation, and localization of the phenomena. Most of the studies reported the concept of compliance related to variations in volume and pressure or its inverse (elastance), primarily in the intracranial compartment. In addition, terms like "accommodation," "compensation," "reserve capacity," and "buffering ability" were used to describe the clinical interpretation. The second part of this review describes the techniques (invasive and non-invasive) and outcomes used to measure ICC. A total of 297 studies were included. The most common method used was invasive, representing 57-88% of the studies. The most commonly assessed variables were related to ICP, especially the absolute values or pulse amplitude. ICP waveforms should be better explored, along with the potential of non-invasive methods once the different aspects of ICC can be measured. Conclusion: ICC monitoring could be considered a complementary resource for ICP monitoring and clinical examination. The combination and validation of invasive/non-invasive or non-invasive measurement methods are required.

Use of non-invasive intracranial pressure pulse waveform to monitor patients with End-Stage Renal Disease (ESRD).

End-stage renal disease (ESRD) is treated mainly by hemodialysis, however, hemodialysis is associated with frequent complications, some of them involve the increased intracranial pressure. In this context, monitoring the intracranial pressure of these patients may lead to a better understanding of how intracranial pressure morphology varies with hemodialysis. This study aimed to follow-up patients with ESRD by monitoring intracranial pressure before and after hemodialysis sessions using a noninvasive method. We followed-up 42 patients with ESRD in hemodialysis, for six months. Noninvasive intracranial pressure monitoring data were obtained through analysis of intracranial pressure waveform morphology, this information was uploaded to Brain4care® cloud algorithm for analysis. The cloud automatically sends a report containing intracranial pressure parameters. In total, 4881 data points were collected during the six months of follow-up. The intracranial pressure parameters (time to peak and P2/P1 ratio) were significantly higher in predialysis when compared to postdialysis for the three weekly sessions and throughout the follow-up period (p<0.01) data showed general improvement in brain compliance after the hemodialysis session. Furthermore, intracranial pressure parameters were significantly higher in the first weekly hemodialysis session (p<0.05). In conclusion, there were significant differences between pre and postdialysis intracranial pressure in patients with ESRD on hemodialysis. Additionally, the pattern of the intracranial pressure alterations was consistent over time suggesting that hemodialysis can improve time to peak and P2/P1 ratio which may reflect in brain compliance.

Intracranial Pressure During the Development of Renovascular Hypertension.

[Figure: see text].

Age as a predictive factor for reduced intracranial compliance in patients with headache / Idade como fator preditor de complacência intracraniana reduzida em pacientes com cefaleia

Abstract Background Increased intracranial pressure (ICP) consists of a set of signs and symptoms related to changes in intracranial compliance (ICC) and ICP. Objective This study presents a retrospective analysis of patients who underwent non-invasive monitoring of ICC based on complaints of headache, correlating decreased brain compliance and increased intracranial pressure. Methods Noninvasive ICC monitoring was performed using a Brain4care device, which contains a strain gauge and a recorder connected to a mechanical device that touches the scalp surface in the frontoparietal area lateral to the sagittal suture. This tool monitors the ICP by identifying small changes in skull measurements that are caused by pressure variations, i.e., skull deformation is associated with the detection of changes in mean ICP. A clinical evaluation of 32 patients with complaints of headache occurred from the analysis of their medical records. Results Of the 32 patients initially chosen, it was possible to complete the analysis of 18 due to the availability of data in the medical records. From the non-invasive monitoring of the ICC, the following data were collected: time-to-peak, P2/P1 ratio, age, and gender. From the statistical analysis of age and P2/P1 ratio, it was noted that as age increases, ICC tends to decrease regardless of sex (p < 0.05). Conclusion This study concluded that there is a correlation between changes in intracranial compliance and headache complaints in outpatients. There was also a relationship between age and decreased intracranial compliance but without a specific pain pattern.

Resumo Antecedentes O aumento da pressão intracraniana (PIC) consiste em um conjunto de sinais e sintomas relacionados a mudanças na complacência intracraniana (CIC) e na PIC. Objetivo Este estudo apresenta uma análise retrospectiva de pacientes que foram submetidos ao monitoramento não invasivo da CIC com base em queixas de cefaleia, correlacionando a diminuição da complacência cerebral e o aumento da pressão intracraniana. Métodos O monitoramento não invasivo da CIC foi realizado utilizando um dispositivo Brain4Care, que contém um medidor de tensão e um gravador conectado a um dispositivo mecânico que toca a superfície do couro cabeludo na área frontoparietal lateral à sutura sagital. Esta ferramenta monitora a PIC identificando pequenas alterações nas medidas do crânio que são causadas por variações de pressão, ou seja, a deformação do crânio está associada à detecção de alterações na PIC média. Uma avaliação clínica de 32 pacientes com queixas de cefaleia ocorreu a partir da análise de seus prontuários médicos. Resultados Dos 32 pacientes inicialmente escolhidos, foi possível concluir a análise de 18 devido à disponibilidade de dados nos prontuários médicos. A partir do monitoramento não invasivo da CIC, foram coletados os seguintes dados: time-to-peak, relação P2/P1, idade e sexo. Da análise estatística de idade e relação P2/P1, observou-se que à medida em que a idade aumenta, a CIC tende a diminuir independentemente do sexo (p < 0,05). Conclusão Este estudo concluiu que existe uma correlação entre as mudanças na CIC e a queixa de cefaleia em pacientes ambulatoriais. Houve também uma relação entre idade e diminuição da CIC, mas sem um padrão de dor específico.