Transcranial Doppler ultrasound in neurocritical care

Intracranial Pressure and Cerebral Hemodynamics in Infants Before and After Glenn Procedure

OBJECTIVES

This prospective cohort study aimed to investigate changes in intracranial pressure (ICP) and cerebral hemodynamics in infants with congenital heart disease undergoing the Glenn procedure, focusing on the relationship between superior vena cava pressure and estimated ICP.

DESIGN

A single-center prospective cohort study.

SETTING

The study was conducted in a cardiac center over 4 years (2019-2022).

PATIENTS

Twenty-seven infants with congenital heart disease scheduled for the Glenn procedure were included in the study, and detailed patient demographics and primary diagnoses were recorded.

INTERVENTIONS

Transcranial Doppler (TCD) ultrasound examinations were performed at three time points: baseline (preoperatively), postoperative while ventilated (within 24-48 hr), and at discharge. TCD parameters, blood pressure, and pulmonary artery pressure were measured.

MEASUREMENTS AND MAIN RESULTS

TCD parameters included systolic flow velocity, diastolic flow velocity (dFV), mean flow velocity (mFV), pulsatility index (PI), and resistance index. Estimated ICP and cerebral perfusion pressure (CPP) were calculated using established formulas. There was a significant postoperative increase in estimated ICP from 11 mm Hg (interquartile range [IQR], 10-16 mm Hg) to 15 mm Hg (IQR, 12-21 mm Hg) postoperatively (p = 0.002) with a trend toward higher CPP from 22 mm Hg (IQR, 14-30 mm Hg) to 28 mm Hg (IQR, 22-38 mm Hg) postoperatively (p = 0.1). TCD indices reflected alterations in cerebral hemodynamics, including decreased dFV and mFV and increased PI. Intracranial hemodynamics while on positive airway pressure and after extubation were similar.

CONCLUSIONS

Glenn procedure substantially increases estimated ICP while showing a trend toward higher CPP. These findings underscore the intricate interaction between venous pressure and cerebral hemodynamics in infants undergoing the Glenn procedure. They also highlight the remarkable complexity of cerebrovascular autoregulation in maintaining stable brain perfusion under these circumstances.

Feasibility, Clinical Potential, and Limitations of Trans-Burr Hole Ultrasound for Postoperative Evaluation of Chronic Subdural Hematoma: A Prospective Pilot Study

BACKGROUND AND OBJECTIVES

Chronic subdural hematoma (CSDH) is commonly managed through burr hole surgery. Routine follow-up using computed tomography (CT) imaging is frequently used at many institutions, contributing to significant radiation exposure. This study evaluates the feasibility, safety, and reliability of trans-burr hole sonography as an alternative postoperative imaging modality, aiming to reduce radiation exposure by decreasing the frequency of CT scans.

METHODS

We conducted a prospective pilot study on 20 patients who underwent burr hole surgery for CSDH. Postoperative imaging included both CT and sonographic examinations through the burr hole. We assessed the ability to measure residual subdural fluid thickness under the burr hole sonographically compared with CT, the occurrence of complications, and the potential factors affecting sonographic image quality. The Pearson correlation coefficient was used to demonstrate relationships between CT and ultrasound and axial and coronal ultrasound.

RESULTS

Sonography through the burr hole was feasible in 73.5% of cases, providing measurements of residual fluid that closely paralleled CT findings, with an average discrepancy of 1.2 mm for axial and 1.4 mm for coronal sonographic views. A strong positive correlation was found between axial and coronal ultrasound (r = 0.955), CT and axial ultrasound (r = 0.936), and CT and coronal ultrasound (r = 0.920). The primary obstacle for sonographic imaging was the presence of air within the burr hole or the subdural space, which typically resolved over time after surgery.

CONCLUSION

Trans-burr hole sonography emerges as a promising technique for postoperative monitoring of CSDH, with the potential to safely reduce reliance on CT scans and associated radiation exposure in selected patients. Our results support further investigation into the extended use of sonography during the follow-up phase. Prospective multicenter studies are recommended to establish the method's efficacy and to explore strategies for minimizing air presence postsurgery.

Digital artery flow hemodynamics: An ultrasonographic study

BACKGROUND

There is a lack of data regarding the baseline hemodynamic blood flow parameters of the wrist and digits. Therefore, we aimed to quantify the digital and radial artery blood flow parameters using ultrasound and assess the influence of patient characteristics on hemodynamics.

METHODS

We analyzed ultrasonographic data from 25 patients (50 hands) between October 2019 and December 2021. Variables of interest included dimensions of the radial artery and index finger (IF) ulnar and radial digital arteries at the palmodigital crease and their corresponding flow parameters. We compared variables among men and women and patients with and without diabetes using Wilcoxon Rank Sum test.

RESULTS

Our cohort consisted of 18 women (36 hands) and three participants with diabetes (six hands). The mean diameter of the IF radial digital artery was 7 mm, and that of the ulnar digital artery was 10 mm. The average peak systolic velocity for the radial digital artery was 21.31 cm/sec, and for the ulnar digital artery, it was 30.03 cm/sec. Comparing men and women, the only significant difference found was in the time-averaged mean velocity for the ulnar digital artery (men:5.66 cm/sec vs. women:9.68 cm/sec, P = 0.02) and volume of flow for the ulnar digital artery (men:10.87cc/min vs. women:18.58cc/min, P = 0.03). We found no differences in blood flow parameters comparing participants with and without diabetes.

CONCLUSION

These data provide a baseline measurement of digital flow hemodynamics that can be used in future studies to model vascular flow after replantation.

Non-invasive technology for brain monitoring: definition and meaning of the principal parameters for the International PRactice On TEChnology neuro-moniToring group (I-PROTECT)

Technologies for monitoring organ function are rapidly advancing, aiding physicians in the care of patients in both operating rooms (ORs) and intensive care units (ICUs). Some of these emerging, minimally or non-invasive technologies focus on monitoring brain function and ensuring the integrity of its physiology. Generally, the central nervous system is the least monitored system compared to others, such as the respiratory, cardiovascular, and renal systems, even though it is a primary target in most therapeutic strategies. Frequently, the effects of sedatives, hypnotics, and analgesics are entirely unpredictable, especially in critically ill patients with multiple organ failure. This unpredictability exposes them to the risks of inadequate or excessive sedation/hypnosis, potentially leading to complications and long-term negative outcomes. The International PRactice On TEChnology neuro-moniToring group (I-PROTECT), comprised of experts from various fields of clinical neuromonitoring, presents this document with the aim of reviewing and standardizing the primary non-invasive tools for brain monitoring in anesthesia and intensive care practices. The focus is particularly on standardizing the nomenclature of different parameters generated by these tools. The document addresses processed electroencephalography, continuous/quantitative electroencephalography, brain oxygenation through near-infrared spectroscopy, transcranial Doppler, and automated pupillometry. The clinical utility of the key parameters available in each of these tools is summarized and explained. This comprehensive review was conducted by a panel of experts who deliberated on the included topics until a consensus was reached. Images and tables are utilized to clarify and enhance the understanding of the clinical significance of non-invasive neuromonitoring devices within these medical settings.

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler in critically ill neonates and children

Point-of-care brain ultrasound and transcranial doppler or color-coded doppler is being increasingly used as an essential diagnostic and monitoring tool at the bedside of critically ill neonates and children. Brain ultrasound has already established as a cornerstone of daily practice in the management of the critically ill newborn for diagnosis and follow-up of the most common brain diseases, considering the easiness to insonate the brain through transfontanellar window. In critically ill children, doppler based techniques are used to assess cerebral hemodynamics in acute brain injury and recommended for screening patients suffering from sickle cell disease at risk for stroke. However, more evidence is needed regarding the accuracy of doppler based techniques for non-invasive estimation of cerebral perfusion pressure and intracranial pressure, as well as regarding the accuracy of brain ultrasound for diagnosis and monitoring of acute brain parenchyma alterations in children. This review is aimed at providing a comprehensive overview for clinicians of the technical, anatomical, and physiological basics for brain ultrasonography and transcranial doppler or color-coded doppler, and of the current status and future perspectives of their clinical applications in critically ill neonates and children.

CONCLUSION

In critically ill neonates, brain ultrasound for diagnosis and follow-up of the most common cerebral pathologies of the neonatal period may be considered the standard of care. Data are needed about the possible role of doppler techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles. In pediatric critical care, doppler based techniques should be routinely adopted to assess and monitor cerebral hemodynamics. New technologies and more evidence are needed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles.

WHAT IS KNOWN

• In critically ill neonates, brain ultrasound for early diagnosis and follow-up of the most common cerebral and neurovascular pathologies of the neonatal period is a cornerstone of daily practice. In critically ill children, doppler-based techniques are more routinely used to assess cerebral hemodynamics and autoregulation after acute brain injury and to screen patients at risk for vasospasm or stroke (e.g., sickle cell diseases, right-to-left shunts).

WHAT IS NEW

• In critically ill neonates, research is currently focusing on the use of novel high frequency probes, even higher than 10 MHz, especially for extremely preterm babies. Furthermore, data are needed about the role of doppler based techniques for the assessment of cerebral perfusion and vasoreactivity of the critically ill neonate with open fontanelles, also integrated with a non-invasive assessment of brain oxygenation. In pediatric critical care, new technologies should be developed to improve the accuracy of brain ultrasound for the assessment of brain parenchyma of critically ill children with fibrous fontanelles. Furthermore, large multicenter studies are needed to clarify role and accuracy of doppler-based techniques to assess cerebral perfusion pressure and its changes after treatment interventions.

Feasibility of Prone Positioning for Brain-injured Patients with Severe Acute Respiratory Distress Syndrome: A Systematic Review and Pilot Study (ProBrain)

BACKGROUND

Prone position is a key component to treat hypoxemia in patients with severe acute respiratory distress syndrome. However, most studies evaluating it exclude patients with brain injuries without any medical evidence.

METHODS

This study includes a systematic review to determine whether brain-injured patients were excluded in studies evaluating prone position on acute respiratory distress syndrome; a prospective study including consecutive brain-injured patients needing prone position. The primary endpoint was the evaluation of cerebral blood flow using transcranial Doppler after prone positioning. Secondary outcomes were intracranial pressure, cerebral perfusion pressure, and tissue oxygen pressure.

RESULTS

From 8,183 citations retrieved, 120 studies were included in the systematic review. Among them, 90 studies excluded brain-injured patients (75%) without any justification, 16 included brain-injured patients (4 randomized, 7 nonrandomized studies, 5 retrospective), and 14 did not retrieve brain-injured data. Eleven patients were included in the authors' pilot study. No reduction of cerebral blood flow surrogates was observed during prone positioning, with diastolic speed values (mean ± SD) ranging from 37.7 ± 16.2 cm/s to 45.2 ± 19.3 cm/s for the right side (P = 0.897) and 39.6 ± 18.2 cm/s to 46.5 ± 21.3 cm/s for the left side (P = 0.569), and pulsatility index ranging from 1.14 ± 0.31 to 1.0 ± 0.32 for the right side (P = 0.145) and 1.14 ± 0.31 to 1.02 ± 0.2 for the left side (P = 0.564) before and during prone position.

CONCLUSIONS

Brain-injured patients are largely excluded from studies evaluating prone position in acute respiratory distress syndrome. However, cerebral blood flow seems not to be altered considering increasing of mean arterial pressure during the session. Systematic exclusion of brain-injured patients appears to be unfounded, and prone position, while at risk in brain-injured patients, should be evaluated on these patients to review recommendations, considering close monitoring of neurologic and hemodynamic parameters.

EDITOR’S PERSPECTIVE

Neuro Point-of-Care Ultrasound

As the scope of point-of-care ultrasound (POCUS) expands in clinical medicine, its application in neurological applications offers a non-invasive, bedside diagnostic tool. With historical insights, detailed techniques and clinical applications, the chapter provides a comprehensive overview of neurology-based POCUS. It examines the applications, emphasizing its role when traditional neuroimaging is inaccessible or unsafe as well advocating for its use as an adjunctive tool, rather than a replacement of advanced imaging. The chapter covers a range of uses of neuro POCUS including assessment of midline shift, intracranial hemorrhage, hydrocephalus, vasospasm, intracranial pressure, cerebral circulatory arrest, and ultrasound-guided lumbar puncture.

Intracranial pressure-flow relationships in traumatic brain injury patients expose gaps in the tenets of models and pressure-oriented management

Background

The protocols and therapeutic guidance established for treating traumatic brain injuries (TBI) in neurointensive care focus on managing cerebral blood flow (CBF) and brain tissue oxygenation based on pressure signals. The decision support process relies on assumed relationships between cerebral perfusion pressure (CPP) and blood flow, pressure-flow relationships (PFRs), and shares this framework of assumptions with mathematical intracranial hemodynamic models. These foundational assumptions are difficult to verify, and their violation can impact clinical decision-making and model validity.

Method

A hypothesis- and model-driven method for verifying and understanding the foundational intracranial hemodynamic PFRs is developed and applied to a novel multi-modality monitoring dataset.

Results

Model analysis of joint observations of CPP and CBF validates the standard PFR when autoregulatory processes are impaired as well as unmodelable cases dominated by autoregulation. However, it also identifies a dynamical regime -or behavior pattern- where the PFR assumptions are wrong in a precise, data-inferable way due to negative CPP-CBF coordination over long timescales. This regime is of both clinical and research interest: its dynamics are modelable under modified assumptions while its causal direction and mechanistic pathway remain unclear.

Conclusions

Motivated by the understanding of mathematical physiology, the validity of the standard PFR can be assessed a) directly by analyzing pressure reactivity and mean flow indices (PRx and Mx) or b) indirectly through the relationship between CBF and other clinical observables. This approach could potentially help personalize TBI care by considering intracranial pressure and CPP in relation to other data, particularly CBF. The analysis suggests a threshold using clinical indices of autoregulation jointly generalizes independently set indicators to assess CA functionality. These results support the use of increasingly data-rich environments to develop more robust hybrid physiological-machine learning models.

Applications of flexible electronics related to cardiocerebral vascular system

Ensuring accessible and high-quality healthcare worldwide requires field-deployable and affordable clinical diagnostic tools with high performance. In recent years, flexible electronics with wearable and implantable capabilities have garnered significant attention from researchers, which functioned as vital clinical diagnostic-assisted tools by real-time signal transmission from interested targets in vivo. As the most crucial and complex system of human body, cardiocerebral vascular system together with heart-brain network attracts researchers inputting profuse and indefatigable efforts on proper flexible electronics design and materials selection, trying to overcome the impassable gulf between vivid organisms and rigid inorganic units. This article reviews recent breakthroughs in flexible electronics specifically applied to cardiocerebral vascular system and heart-brain network. Relevant sensor types and working principles, electronics materials selection and treatment methods are expounded. Applications of flexible electronics related to these interested organs and systems are specially highlighted. Through precedent great working studies, we conclude their merits and point out some limitations in this emerging field, thus will help to pave the way for revolutionary flexible electronics and diagnosis assisted tools development.

Diagnosis and Treatment of Severe Traumatic Brain Injury in Idiopathic Intracranial Hypertension Syndrome

OBJECTIVE

A topic of current research is the development of a new approach to the diagnosis and treatment of severe brain injury taking into consideration its main pathophysiological mechanism-idiopathic intracranial hypertension syndrome. The goal of this study was to identify Doppler patterns of unfavorable craniocerebral injury conditions to form a consistent algorithm of treatment measures to reduce secondary brain damage in patients with severe craniocerebral trauma.

METHODS

Transcranial Doppler imaging is a prospective method, which allows quick and noninvasive assessment of the intracerebral blood flow dynamics right at the patient's bedside. Due to the operator-dependent nature of this method, clinical interpretation can often be contradictory. As a result, no clear criteria for therapy correction have yet been formulated based on this neuroimaging method.

RESULTS

Analysis of the therapy performed allowed us to specify the options for the hyperosmolar solutions for the correction of idiopathic intracranial hypertension syndrome.

CONCLUSIONS

No statistically significant difference in effectiveness was shown between mannitol and hypertonic saline solutions.

Hyperemia in head injury: can transcranial doppler help to personalize therapies for intracranial hypertension?

Introduction

An increase in cerebral blood flow is frequent after traumatic brain injury (TBI) and can lead to brain swelling and refractory intracranial hypertension. We hypothesized that Transcranial EcoDoppler (TCD) monitoring could be useful to detect the cause of intracranial hypertension in these patients. Our main objective was to investigate if the increase of velocity in the middle cerebral artery (MCA) on TCD could be associated with intracranial hypertension.

Methods

We retrospectively studied TBI patients consecutively monitored with TCD. Hyperemia was defined as MCA mean velocity higher than 80 cm/s. Intracranial hypertension was considered when hyperosmolar therapy, hyperventilation, or deep sedation was used.

Results

We found hyperemia in 40 patients out of 118 (33.9%). On average, it started at day 2.1 ± 0.9 from admission and significantly increased (MCA velocity at day 1: 74 ± 25 cm/s vs. 109 ± 36 cm/s at day 4; p < 0.001). Intracranial hypertension was significantly associated with hyperemia, occurring in 92.5% of hyperemic and 51.3% of non-hyperemic patients (p < 0.001). Moreover, we found that hyperemia preceded severe intracranial hypertension (p < 0.0001). In a logistic regression model, hyperemia was the only variable significantly correlated with intracranial hypertension (OR 10.64; p < 0.001).

Discussion

Hyperemia was frequent in our population of TBI patients and preceded intracranial hypertension. TCD monitoring, if performed on a daily regular basis, can be a useful method to detect this phenomenon and to guide the therapy. It could be a tool for a cause-oriented therapy of intracranial hypertension.

Assessment of Midline Shift in Postdecompressive Craniectomy Patients in Neurocritical Care: Comparison between Transcranial Ultrasonography and Computerized Tomography

Background

Monitoring and evaluation of intracranial structures remain a fundamental element in the neurointensive care unit. Most used technique to monitor progression is the use of computed tomography (CT) in intracranial hemorrhage (ICH) or stroke. Rapid assessment of brain pathology can be made using CT to analyze the midline shift (MLS), hematoma expansion, and ventricular size, but transferring a patient who is intubated is time and resource-consuming task. Ultrasonography is a noninvasive technique, portable, and has the possibility of fast interpretation.

Aims and Objectives

To measure the brain MLS in decompressive craniectomy patients using transcranial ultrasonography (TCS) and compare the correlation of these results with CT scan measurements of MLS in the same patient.

Materials and Methods

Patients who have undergone decompressive craniectomy due to various reasons like ICH, traumatic brain injury, etc., and have a MLS. Trans cranial ultrasonography was assessed by a single consultant (Neuro Critical Care Intensivist) who was blinded for the CT scan measurement. CT scan measurement of MLS was assessed by a neuroradiologist using standard guidelines, who was blinded for the TCS results of MLS. The finding of a MLS >0.5 cm in the CT scan was considered a significant MLS.

Results

A total of 31 patients were recruited for the study. MLS measured using CT was 0.91 ± 0.67 cm. MLS via TCS was 0.91 ± 0.66 cm. A significant MLS via TCS was found in 77.4%. Intraclass correlation coefficient (ICC) was calculated between CT-MLS and TCS MLS and obtained the value of ICC as 0.996, indicating an almost perfect agreement.

Conclusion

Patients after decompressive craniectomy may present as an ideal candidate to visualize intracerebral anatomy with a high resolution. TCS might be considered as an alternative to CT to measure MLS in decompressive craniectomy patients.

Intracranial pressure monitoring in neurosurgery: the present situation and prospects

Intracranial pressure (ICP) is one of the most important indexes in neurosurgery. It is essential for doctors to determine the numeric value and changes of ICP, whether before or after an operation. Although external ventricular drainage (EVD) is the gold standard for monitoring ICP, more and more novel monitoring methods are being applied clinically.Invasive wired ICP monitoring is still the most commonly used in practice. Meanwhile, with the rise and development of various novel technologies, non-invasive types and invasive wireless types are gradually being used clinically or in the testing phase, as a complimentary approach of ICP management. By choosing appropriate monitoring methods, clinical neurosurgeons are able to obtain ICP values safely and effectively under particular conditions.This article introduces diverse monitoring methods and compares the advantages and disadvantages of different monitoring methods. Moreover, this review may enable clinical neurosurgeons to have a broader view of ICP monitoring.

Transcranial Doppler Ultrasonography detection on cerebrovascular flow for evaluating neonatal hypoxic-ischemic encephalopathy modeling

Objective

This study aimed to investigate the feasibility of Transcranial Doppler Ultrasonography (TCD) in evaluating neonatal hypoxic-ischemic encephalopathy (NHIE) modeling through monitoring the alteration of cerebrovascular flow in neonatal hypoxic-ischemic (HI) rats.

Methods

Postnatal 7-day-old Sprague Dawley (SD) rats were divided into the control group, HI group, and hypoxia (H) group. TCD was applied to assess the changes of cerebral blood vessels, cerebrovascular flow velocity, and heart rate (HR) in sagittal and coronal sections at 1, 2, 3, and 7 days after the operation. For accuracy, cerebral infarct of rats was examined by 2,3,5-Triphenyl tetrazolium chloride (TTC) staining and Nissl staining to simultaneously verify the establishment of NHIE modeling.

Results

Coronal and sagittal TCD scans revealed obvious alteration of cerebrovascular flow in main cerebral vessels. Obvious cerebrovascular back-flow was observed in anterior cerebral artery (ACA), basilar artery (BA), middle cerebral artery (MCA) of HI rats, along with accelerated cerebrovascular flows in the left internal carotid artery (ICA-L) and BA, decreased flows in right internal carotid artery (ICA-R) relative to those in the H and control groups. The alterations of cerebral blood flows in neonatal HI rats indicated successful ligation of right common carotid artery. Besides, TTC staining further validated the cerebral infarct was indeed caused due to ligation-induced insufficient blood supply. Damage to nervous tissues was also revealed by Nissl staining.

Conclusion

Cerebral blood flow assessment by TCD in neonatal HI rats contributed to cerebrovascular abnormalities observed in a real-time and non-invasive way. The present study elicits the potentials to utilize TCD as an effective means for monitoring the progression of injury as well as NHIE modeling. The abnormal appearance of cerebral blood flow is also beneficial to the early warning and effective detection in clinical practice.

Assessment of cerebral blood flow velocities, brain midline shift and optic nerve sheath diameter by ultrasound in patients undergoing elective craniotomy: A prospective observational feasibility study

BACKGROUND

Brain ultrasound allows measuring the cerebral flow velocity, brain midline shift and optic nerve sheath diameter. Literature is scarce in determining the feasibility to perioperatively perform these measurements altogether and the cerebrovascular behavior in patients scheduled for elective craniotomy.

METHODS

We assessed bilateral cerebral flow velocities, composite index, brain midline shift and optic nerve sheath diameter by cerebral ultrasound in patients scheduled for elective craniotomy before anesthetic induction, at extubation, and at 6 and 24 h after. The aim was to assess the feasibility of brain ultrasound in patients for elective craniotomy and to describe the changes in cerebral flow velocities, brain midline shift and optic nerve sheath diameter from baseline values at different times in the postoperative period.

RESULTS

Sixteen patients were included, of these two were excluded from analysis due to an inadequate sonographic window. There were no changes throughout the study regarding cerebral flow velocity, brain midline shift nor optic nerve sheath diameter assessments. All parameters were maintained in the physiological range without significant variations during the procedure. No perioperative complications were detected.

CONCLUSIONS

The results of our study show the feasibility to perform a perioperative assessment of cerebral flow velocity, brain midline shift or optic nerve sheath diameter jointly and successfully to obtain additional information of baseline cerebral hemodynamics in patients scheduled for elective craniotomy and their postoperative changes during the first 24 h. Future studies with lager samples are needed to address the efficacy of cerebral ultrasound as a monitoring tool.

The effectiveness of high-tone therapy in the complex rehabilitation of servicemen with post-traumatic stress disorder complicated by traumatic brain injury

INTRODUCTION

As a result of local military conflicts that have become more frequent over the past decades, the number of military personnel subjected to combat stress has sharply increased. More than 50% of them suffer from combat posttraumatic stress disorder. The most common comorbidity in this category of patients is a traumatic brain injury. Due to the undesirability of the long-term use of pharmacological agents, for rehabilitation, preference should be given to physiotherapeutic procedures.

OBJECTS AND METHODS

We examined 50 patients with post-traumatic stress disorder in combination with a closed craniocerebral injury. Group 1-25 patients received standard complex treatment at the sanatoriumresort rehabilitation stage (diet therapy, climatotherapy, balneotherapy, exercise therapy, psychotherapy). Group 2-25 patients, in addition to the standard complex treatment, received a course of high-tone therapy.

RESULTS

Complex rehabilitation of patients with the use of high-tone therapy contributes to a significant decrease in astheno-neurotic (p < 0.05) and asthenic depressive (p < 0.01) syndromes and has a psycho-relaxing effect on anxiety syndrome (p < 0.01). There was also a decrease in the severity of pyramidal symptoms and regression of the vestibulo-atactic syndrome (p < 0.05). The course application of hightone therapy was accompanied by a significant restoration of the elastotonic properties of the vascular wall and an improvement in cerebral perfusion (p < 0.05). Positive dynamics of electrophysiological indicators were noted: a decrease in the intensity of slow rhythms against the background of an increase in the frequency and intensity of the alpha rhythm in both hemispheres (p < 0.05), which indicates the harmonization of the bioelectrical activity of the brain.

Transcranial ultrasonography imaging of a suprasellar meningioma: A case description and technical notes

Background

Computed tomography (CT) and magnetic resonance (MR) represent the gold standard for evaluating intracranial tumours, such as meningiomas; most meningiomas can be managed by surveillance and clinical follow-up, therefore, the ideal technology should be cheap, non-invasive, safe and able to reduce radiation exposure. Transcranial colour-coded duplex sonography (TCCS) can detect space-occupying lesions, but its full potential for clinical practice is still unexpressed.

Aims and Methods

We describe the ability of TCCS to directly and accurately image, in a 77-year-old woman hospitalised for septic shock and coma, a suprasellar meningioma with a spatial resolution very similar to CT.

Results

The meningioma was clearly visualised as a roundish mass, with well-defined borders, heterogeneously hyperechogenic compared with the surrounding brain structures; multiple intralesional calcifications were detectable as highly echogenic spots. Latero-lateral and antero-posterior diameters were well measurable.

Discussion

TCCS should not be considered as an alternative to CT and MR imaging, but it might have a complementary role, useful for use at the bedside in uncooperative or non-transportable patients and for follow-up, when an adequate acoustic window is guaranteed. Neurologists and neuroradiologists should further explore the full potential of this technology.

The predictive value of deep learning-based cardiac ultrasound flow imaging for hypertrophic cardiomyopathy complicating arrhythmias

OBJECTIVE

To investigate the predictive value of deep learning-based cardiac ultrasound flow imaging for hypertrophic cardiomyopathy (HCM) complicated by arrhythmias.

METHODS

The clinical data of 158 patients with hypertrophic cardiomyopathy were retrospectively collected from July 2019 to December 2021, and additionally divided into training group 106 cases, validation group 26 cases and test group 26 cases according to the ratio of 4:1:1, and divided into concurrent and non-concurrent groups according to whether they were complicated by arrhythmia or not, respectively. General data of patients (age, gender, BMI, systolic blood pressure, diastolic blood pressure, HR) were collected, a deep learning model for cardiac ultrasound flow imaging was established, and image data, LVEF, LAVI, E/e', vortex area change rate, circulation intensity change rate, mean blood flow velocity, and mean EL value were extracted.

RESULTS

The differences in general data (age, gender, BMI, systolic blood pressure, diastolic blood pressure, HR) between the three groups were not statistically significant, P > 0.05. The differences in age, gender, BMI, systolic blood pressure, diastolic blood pressure, HR between the patients in the concurrent and non-concurrent groups in the training group were not statistically significant, P > 0.05.

CONCLUSIONS

Deep learning-based cardiac ultrasound flow imaging can identify cardiac ultrasound images more accurately and has a high predictive value for arrhythmias complicating hypertrophic cardiomyopathy, and vortex area change rate, circulation intensity change rate, mean flow velocity, mean EL, LAVI, and E/e' are all risk factors for arrhythmias complicating hypertrophic cardiomyopathy.

Application of transcranial Doppler in cerebrovascular diseases

Transcranial Doppler (TCD) is a rapid and non-invasive diagnostic technique that can provide real-time measurements of the relative changes in cerebral blood velocity (CBV). Therefore, TCD is a useful tool in the diagnosis and treatment of clinical cerebrovascular diseases (CVDs). In this review, the basic principles of TCD and its application in CVD were outlined. Specifically, TCD could be applied to evaluate occlusive CVD, assess collateral circulation in patients with ischemic stroke, and monitor cerebral vascular occlusion before and after thrombolysis as well as cerebral vasospasm (VSP) and microembolization signals after aneurysmal subarachnoid hemorrhage (SAH). Moreover, TCD could predict short-term stroke and transient cerebral ischemia in patients with anterior circulation occlusion treated with endovascular therapy and in patients with anterior circulation vascular occlusion. Additionally, TCD not only could monitor blood velocity signals during carotid endarterectomy (CEA) or carotid artery stenting (CAS) but also allowed earlier intervention through early recognition of sickle cell disease (SCD). Presently, TCD is a useful prognostic tool to guide the treatment of CVD. On the one hand, TCD is more commonly applied in clinical research, and on the other hand, TCD has an increasing role in the management of patients. Collectively, we review the principles and clinical application of TCD and propose some new research applications for TCD.

Follow-Up by Transcranial Doppler After Rupture of a Giant Intracranial Aneurysm

Giant intracranial aneurysms (GIA) are rare and manifest primarily through subarachnoid hemorrhage (SAH), cerebral ischemia, or progressive symptoms of mass effect. Transcranial Doppler (TCD) can be used to monitor cerebral vasospasm after treatment of intracranial aneurysm allowing the adjustment of therapeutics and avoiding complications. The authors present a clinical case of a patient with a ruptured intracranial giant aneurysm in which TCD was essential to monitor vasospasm and intracranial hypertension (IH). A 53-year-old male was admitted due to a sudden headache and impaired consciousness, left hemiparesis, and dysarthria. Cerebral CT scan and CT angiography at admission showed a giant aneurysm of the right middle cerebral artery (MCA) with extensive and diffuse intraventricular SAH of Fisher grade IV and Hunt and Hess grade 4. Clipping, placement of an intracranial pressure sensor, and external ventricular drain (EVD) were performed on the same day, with difficulty in preserving the M2 branch and complicated by postoperative extensive right MCA ischemia. On day three of hospitalization, TCD revealed an increased pulsatility index (>1.5) with clinical deterioration leading to re-intervention for a decompressive craniectomy. On day six, a TCD follow-up was performed to monitor blood flow complications, and particularly vasospasm, showing a severe increase in middle blood flow velocity (MBFV) in the right MCA of 205 cm/s and Lindegaard Index > 6. Daily surveillance by TCD was maintained to guide clinical management since the attempt to withdraw the EVD led to clinical deterioration with subsequent worsening of vasospasm. Improvement occurred after surgery as ventriculoperitoneal shunt insertion was performed. TCD had a major role in the clinical orientation of SAH as well as in intracranial pressure management and was decisive to establish long-term treatment.

Development of a Flow Phantom for Transcranial Doppler Ultrasound Quality Assurance

Anecdotal evidence was recently brought to our attention suggesting a potential difference in velocity estimates between transcranial Doppler (TCD) systems when measuring high velocities (∼200 cm/s) close to the threshold for sickle cell disease stroke prevention. As we were unable to identify a suitable commercial TCD phantom, a middle cerebral artery (MCA) flow phantom was developed to evaluate velocity estimates from different devices under controlled conditions. Time-averaged velocity estimates were obtained using two TCD devices: a Spencer Technologies ST³ Doppler system (ST³ PMD150, Spencer Technologies, Seattle, WA, USA) and a DWL Dopplerbox (DWL Compumedics, SN-300947, Singen, Germany). These were compared with velocity estimates obtained using a Zonare duplex scanner (Zonare Medical Systems, Mountain View, CA, USA), with timed collection of fluid as the gold standard. Bland-Altman analysis was performed to compare measurements between devices. Our tests confirmed that velocities measured with the DWL TCD system were +4.1 cm/s (+3.7%; limits of agreement [LoA]: 2%, 5%; p = 0.03) higher than the Spencer system when measuring a velocity 110 cm/s and +12 cm/s higher (+5.7 %; LoA: 4.8%, 6.6%; p = 0.03) when measuring velocities of 210 cm/s, close to the diagnostic threshold for stroke intervention. We found our MCA phantom to be a valuable tool for systematically quantifying differences in TCD velocity estimates between devices, confirming that the DWL system gave consistently higher readings than the Spencer ST³ system. Differences become more pronounced at high velocities, which explains why they were not identified earlier. Our findings have clinical implications for centers using TCD to monitor patients with sickle cell disease, as extra care may be needed to adjust for bias between manufacturers when making treatment decisions about children with sickle cell with velocities close to the diagnostic threshold.

Increased pulsatility index of the basilar artery is a risk factor for neurological deterioration after stroke: a case control study

Background

Higher pulsatility of the middle cerebral artery (MCA) is known to be associated with stroke progression. We investigated whether pulsatility index (PI) of the basilar artery (BA) can predict neurological deterioration (ND) after acute cerebral infarction.

Methods

A total of 708 consecutive patients with acute ischemic stroke who had undergone transcranial Doppler (TCD) ultrasonography were included. ND was defined as an increase in the National Institutes of Health Stroke Scale scores by two or more points after admission. The patients were categorized into quartiles according to BA PI. Multivariable logistic regression analysis was performed to examine whether BA PI is independently associated with ND.

Results

BA PI was well correlated with the right (n = 474, r² = 0.573, P < 0.001) by Pearson correlation analysis although MCA PI could not be measured from right MCA (n = 234, 33.05%) and left MCA (n = 252, 35.59%) by TCD owing to insufficient temporal bone window. Multivariable logistic regression analysis including age, sex, cerebral atherosclerosis burden, National Institutes of Health Stroke Scale at admission, and the proportion of patients with current smoking status, hypertension, diabetes mellitus, atrial fibrillation revealed that the higher BA PI (odds ratio, 3.28; confidence interval, 1.07–10.17; P = 0.038) was independently associated with ND.

Conclusions

BA PI, which would be identified regardless of temporal window, could predict ND among acute stroke patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40885-022-00210-9.

Loss of cerebral blood flow and cerebral perfusion pressure in brain death: A transcranial Duplex ultrasonography study

PURPOSE

We investigated cerebral perfusion pressure (CPP) at the time loss of cerebral blood flow (CBF) occurred during brain death (BD). We hypothesized that a critical closing pressure (CrCP) may be reached before CPP drops to 0 mmHg.

MATERIALS AND METHODS

14 patients with increasing intracranial pressure (ICP) leading to BD were included. Transcranial Duplex (TCD) ultrasonography was used to investigate CBF. Starting at a CPP of 30 mmHg, TCD was repeated until waveforms indicated loss of CBF. We then analyzed CPP by the time TCD indicated absent CBF and clinical BD was established.

RESULTS

In 12 patients, CPP was positive when clinical BD was manifest and TCD illustrated absent CBF. Across all patients, mean CPP at clinical BD manifestation was 10.0 mmHg (range 0-20 mmHg); mean CPP by the time CBF stopped was 7.5 mmHg (0-20 mmHg). In four patients, clinical BD preceded loss of CBF. Here, the mean CPP difference from clinical BD to loss of CBF was 8.8 mmHg (5-15 mmHg).

CONCLUSIONS

CrCP may be reached although CPP is still positive, resulting in complete loss of CBF and BD. By including bedside TCD, neuromonitoring may contribute to early identification of patients at risk to experience loss of CBF and subsequent BD.

Treating the body to prevent brain injury: lessons learned from the coronavirus disease 2019 pandemic

PURPOSE OF REVIEW

We aim to provide the current evidence on utility and application of neuromonitoring tools including electroencephalography (EEG), transcranial Doppler (TCD), pupillometry, optic nerve sheath diameter (ONSD), cerebral near-infrared spectroscopy (cNIRS), somatosensory-evoked potentials (SSEPs), and invasive intracranial monitoring in COVID-19. We also provide recent evidence on management strategy of COVID-19-associated neurological complications.

RECENT FINDINGS

Despite the common occurrence of neurological complications, we found limited use of standard neurologic monitoring in patients with COVID-19. No specific EEG pattern was identified in COVID-19. Frontal epileptic discharge was proposed to be a potential marker of COVID-19 encephalopathy. TCD, ONSD, and pupillometry can provide real-time data on intracranial pressure. Additionally, TCD may be useful for detection of acute large vessel occlusions, abnormal cerebral hemodynamics, cerebral emboli, and evolving cerebral edema at bedside. cNIRS was under-utilized in COVID-19 population and there are ongoing studies to investigate whether cerebral oxygenation could be a more useful parameter than peripheral oxygen saturation to guide clinical titration of permissive hypoxemia. Limited data exists on SSEPs and invasive intracranial monitoring.

SUMMARY

Early recognition using standardized neuromonitoring and timely intervention is important to reduce morbidity and mortality. The management strategy for neurological complications is similar to those without COVID-19.

Multimodality Monitoring for Delayed Cerebral Ischemia in Subarachnoid Hemorrhage: A Mini Review

Aneurysmal subarachnoid hemorrhage is a disease with high mortality and morbidity due in large part to delayed effects of the hemorrhage, including vasospasm, and delayed cerebral ischemia. These two are now recognized as overlapping yet distinct entities, and supportive therapies for delayed cerebral ischemia are predicated on identifying DCI as quickly as possible. The purpose of this overview is to highlight diagnostic tools that are being used in the identification of DCI in the neurocritical care settings.

Evaluation of neurosonology versus digital subtraction angiography in acute stroke patients

Stroke is one of the most common neurological disorders with a high incidence in Middle-eastern regions. We aimed to assess the diagnostic accuracy of neurovascular ultrasound to detect of cerebral artery stenosis compared to digital subtraction angiography (DSA) as a gold standard method. Eighty patients presenting with symptoms of cerebral ischemia were enrolled in the study. They were examined by cervical color Doppler ultrasound and TCCS to determine stenosis of extracranial and intracranial arteries, respectively. DSA was performed 24-48 h after the initial examination. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of neurovascular ultrasound in comparison to DSA were calculated. The agreement between the two methods was determined by kappa statistics. Eighty patients (60% male, 40% female) with a mean age of 61.32 ± 12.6 years were included. In 65% of patients, stenosis in carotid artery caused ischemic symptoms. We did not observe any stenosis in anterior cerebral artery, posterior cerebral artery and basilar artery in patients. The agreement between the neurovascular ultrasound and DSA in various arterial vessels was 0.9 for common carotid artery, 0.86 for internal carotid artery, 0.78 for middle cerebral artery, and 0.86 for vertebral artery. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and kappa value of the neurovascular ultrasound for detecting stenosis regarding the arterial segments were 84.8%, 81%, 92.6%, 65.4%, 83.8, and 0.71, respectively. In conclusion, the neurovascular ultrasound is a valuable, non-invasive, and repeatable method to investigate cerebral artery stenosis with high diagnostic accuracy.

Practice Recommendations for Transcranial Doppler Ultrasonography in Critically Ill Children in the Pediatric Intensive Care Unit: A Multidisciplinary Expert Consensus Statement

Transcranial Doppler ultrasonography (TCD) is being used in many pediatric intensive care units (PICUs) to aid in the diagnosis and monitoring of children with known or suspected pathophysiological changes to cerebral hemodynamics. Standardized approaches to scanning protocols, interpretation, and documentation of TCD examinations in this setting are lacking. A panel of multidisciplinary clinicians with expertise in the use of TCD in the PICU undertook a three-round modified Delphi process to reach unanimous agreement on 34 statements and then create practice recommendations for TCD use in the PICU. Use of these recommendations will help to ensure that high quality TCD images are captured, interpreted, and reported using standard nomenclature. Furthermore, use will aid in ensuring reproducible and meaningful study results between TCD practitioners and across PICUs.

Ultrasound Diagnostic Method in Vascular Dementia: Current Concepts

BACKGROUND

Increasing interest in identifying cerebral hemodynamics alterations as a cause of possible onset or worsening of cognitive impairment in elderly patients with vascular risk factors.

INTRODUCTION

Intracranial ultrasound is a non-invasive, repeatable inexpensive method for recording variation of the cerebral vascular tree in physiological and pathological conditions and the diagnosis of vascular dementia (VaD).

METHODS

PubMed, Embase, Cochrane library and reference lists have been searched for articles published until March 30, 2020.

RESULTS

Clinical studies reported different Transcranial Doppler (TCD) parameters and subsequently transcranial duplex with color code (TCCD) in patients affected by vascular dementia. The number of studies using TCCD remains limited and most of the available data are still based on TCD. However, the use of transcranial Doppler could better stratify elderly patients with initial signs of cognitive impairment.

CONCLUSION

Intracranial ultrasound employment to detect cerebral hemodynamic changes in VaD patients has been briefly discussed in this review.

Transcranial Doppler Combined With Quantitative Electroencephalography Brain Function Monitoring for Estimating the Prognosis of Patients With Posterior Circulation Cerebral Infarction

Posterior circulation cerebral infarction (PCCI) can lead to deceased infratentorial cerebral blood flow (CBF) and metabolism. Neural activity is closely related to regional cerebral blood flow both spatially and temporally. Transcranial Doppler (TCD) combined with quantitative electroencephalography (QEEG) is a technique that evaluates neurovascular coupling and involves synergy between the metabolic and vascular systems. This study aimed to monitor brain function using TCD-QEEG and estimate the efficacy of TCD-QEEG for predicting the prognosis of patients with PCCI. We used a TCD-QEEG recording system to perform quantitative brain function monitoring; we recorded the related clinical variables simultaneously. The data were analyzed using a Cox proportional hazards regression model. Receiver-operating characteristic (ROC) curve analysis was used to evaluate the cut-off for the diastolic flow velocity (VD) and (delta + theta)/(alpha + beta) ratio (DTABR). The area under the ROC curve (AUROC) was calculated to assess the predictive validity of the study variables. Forty patients (aged 63.7 ± 9.9 years; 30 men) were assessed. Mortality at 90 days was 40%. The TCD indicators of VD [hazard ratio (HR) 0.168, confidence interval (CI) 0.047-0.597, p = 0.006] and QEEG indicators of DTABR (HR 12.527, CI 1.637-95.846, p = 0.015) were the independent predictors of the clinical outcomes. The AUROC after combination of VD and DTABR was 0.896 and showed better predictive accuracy than the Glasgow Coma Scale score (0.75), VD (0.76), and DTABR (0.781; all p < 0.05). TCD-QEEG provides a good understanding of the coupling mechanisms in the brain and can improve our ability to predict the prognosis of patients with PCCI.

Functional interferometric diffusing wave spectroscopy of the human brain

Cerebral blood flow (CBF) is essential for brain function, and CBF-related signals can inform us about brain activity. Yet currently, high-end medical instrumentation is needed to perform a CBF measurement in adult humans. Here, we describe functional interferometric diffusing wave spectroscopy (fiDWS), which introduces and collects near-infrared light via the scalp, using inexpensive detector arrays to rapidly monitor coherent light fluctuations that encode brain blood flow index (BFI), a surrogate for CBF. Compared to other functional optical approaches, fiDWS measures BFI faster and deeper while also providing continuous wave absorption signals. Achieving clear pulsatile BFI waveforms at source-collector separations of 3.5 cm, we confirm that optical BFI, not absorption, shows a graded hypercapnic response consistent with human cerebrovascular physiology, and that BFI has a better contrast-to-noise ratio than absorption during brain activation. By providing high-throughput measurements of optical BFI at low cost, fiDWS will expand access to CBF.

Identification of intracranial hemorrhage progression by transcranial point-of-care ultrasound in a patient with prior hemicraniectomy: a case report

Transcranial ultrasound has been described as a tool to identify intracranial pathology, however, it is seldom used in the adult patient population due to poor imaging windows and rapid availability of more advanced imaging such as CT and MRI. We report a unique population in which transcranial ultrasound may be beneficial: those with a history of hemicraniectomy. We present a case of a 65-year-old male with a history of hemicraniectomy who suffered head trauma after a fall from his wheelchair. An initial non-contrast head CT scan identified an intracranial hemorrhage. Point-of-care bedside transcranial ultrasound was able to identify the progression of intracranial hemorrhage, which was confirmed by interval head CT. This prompted repeat CT imaging followed by neurosurgical intervention with the placement of an external ventricular drain in the right lateral ventricle. While ultrasound is unlikely to replace the need for more advanced imaging in these patients, point-of-care transcranial ultrasound may be a useful tool that can be employed rapidly at the bedside for interval screening in patients with hemicraniectomy and concern for new or worsening intracranial hemorrhage.

Ultrasound as a Useful Tool in Hydrocephalus Management During Pregnancy: A Case Report

A 38-year-old pregnant woman in her 24th week of gestation was admitted to our neurosurgical intensive care unit with a 5-cm cerebellar hemangioblastoma and acute hydrocephalus. Initial management included the placement of an external ventricular drain to prevent neurological deterioration. Five days after the initial diagnosis, the patient successfully underwent a neurosurgical intervention to remove the lesion. Transcranial ultrasound was used to determine the optimal ventricular drain level and facilitate weaning, bypassing the need for cerebral computed tomography and cerebral magnetic resonance imaging, which would have otherwise been necessary in postoperative follow-up.

Impact of Graded Passive Cycling on Hemodynamics, Cerebral Blood Flow, and Cardiac Function in Septic ICU Patients

Background: In-bed passive cycling is considered a safe and feasible early mobilization technique in intensive care unit (ICU) patients who are unable to exercise actively. However, the impact of varying intensity of passive cycling on perfusion and function of ischemia-prone organs is unknown. In this study, we assessed the impact of a graded passive cycling protocol on hemodynamics, cerebral blood flow, and cardiac function in a cohort of septic ICU patients. Methods: In consecutive patients presenting with sepsis, we measured global hemodynamic indices, middle cerebral artery velocity (MCAv), and cardiac function in response to a graded increase in passive cycling cadence. Using 5-min stages, we increased cadence from 5 to 55 RPM in increments of 10 RPM, preceded and followed by 5 min baseline and recovery periods at 0 RPM. The mean values obtained during the last 2 min of each stage were compared within and between subjects for all metrics using repeated-measures ANOVA. Results: Ten septic patients (six males) completed the protocol. Across patients, there was a 5.2% reduction in MCAv from baseline at cycling cadences of 25-45 RPM with a dose-dependent decrease of MCAv of > 10% in four of the 10 patients enrolled. There was a 16% increase in total peripheral resistance from baseline at peak cadence of 55 RPMs and no changes in any other measured hemodynamic parameters. Patient responses to passive cycling varied between patients in terms of magnitude, direction of change, and the cycling cadence at which these changes occurred. Conclusions: In septic patients, graded passive cycling is associated with dose-dependent decreases in cerebral blood flow, increases in total peripheral resistance, and either improvement or worsening of left ventricular function. The magnitude and cadence threshold of these responses vary between patients. Future studies should establish whether these changes are associated with clinical outcomes, including cognitive impairment, vasopressor use, and functional outcomes.

Design of 2D Sparse Array Transducers for Anomaly Detection in Medical Phantoms

Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower array, have been considered for their potential as conformable transducers able to image within a focal range of 30-80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions. Two evaluation criteria, peak sidelobe level (PSL) and integrated sidelobe ratio (ISLR), are used to access the performance of each array configuration. Subsequently, a log spiral array pattern with -19.33 dB PSL and 2.71 dB ISLR has been selected as the overall optimal design. Two prototype transducers with the selected log spiral array pattern have been fabricated and characterised, one using a fibre composite element composite array transducer (CECAT) structure, the other using a conventional 1-3 composite (C1-3) structure. The CECAT device demonstrates improved coupling coefficient (0.64 to 0.59), reduced mechanical cross-talk between neighbouring array elements (by 10 dB) and improved operational bandwidth (by 16.5%), while the C1-3 device performs better in terms of sensitivity (~50%). Image processing algorithms, such as Hough transform and morphological opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios, including bespoke phantoms using tissue mimicking material. Experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.

Clinical Applications of Ultrasonography in Neurocritically Ill Patients

Ultrasonography is part of the multimodal monitoring of the neurocritical patient. Through transcranial color Doppler ultrasound, carotid-color Doppler ultrasound, and ocular ultrasound it is possible to diagnose and monitor a multitude of pathological conditions, such as cerebrovascular events, vasospasm, Terson syndrome, carotid atheromatosis, and brain death. Furthermore, these techniques enable the monitoring of the intracranial pressure, the cerebral perfusion pressure, and the midline deviation, which allows us to understand the patient's neurocritical pathology at their bedside, in a noninvasive way. Although none of these tools have yet been shown to improve patient prognosis, the dissemination of knowledge and management of neurovascular ultrasonography could significantly improve the comprehensive management of neurocritical patients.

Neurocritical Care Outcomes, Research, and Technology: A Review

Importance

Neurocritical care has grown into an organized specialty that may have consequences for patient care, outcomes, research, and neurointensive care (neuroICU) technology.

Observations

Neurocritical care improves care and outcomes of the patients who are neurocritically ill, and neuroICUs positively affect the financial state of health care systems. The development of neurocritical care as a recognized subspecialty has fostered multidisciplinary research, neuromonitoring, and neurocritical care information technology, with advances and innovations in practice and progress.

Conclusions and Relevance

Neurocritical care has become an important part of health systems and an established subspecialty of neurology. Understanding its structure, scope of practice, consequences for care, and research are important.

NeoDoppler: New ultrasound technology for continous cerebral circulation monitoring in neonates

BACKGROUND

There is a strong need for continuous cerebral circulation monitoring in neonatal care, since suboptimal cerebral blood flow may lead to brain injuries in preterm infants and other critically ill neonates. NeoDoppler is a novel ultrasound system, which can be gently fixed to the anterior fontanel and measure cerebral blood flow velocity continuously in different depths of the brain simultaneously. We aimed to study the feasibility, accuracy, and potential clinical applications of NeoDoppler in preterm infants and sick neonates.

METHOD

Twenty-five infants born at different gestational ages with a variety of diagnoses on admission were included. The probe was placed over the anterior fontanel, and blood flow velocity data were continuously recorded. To validate NeoDoppler, we compared the measurements with conventional ultrasound; agreement was assessed using Bland-Altman plots.

RESULTS

NeoDoppler can provide accurate and continuous data on cerebral blood flow velocity in several depths simultaneously. Limits of agreement between the measurements obtained with the two methods were acceptable.

CONCLUSION

By monitoring the cerebral circulation continuously, increased knowledge of cerebral hemodynamics in preterm infants and sick neonates may be acquired. Improved monitoring of these vulnerable brains during a very sensitive period of brain development may contribute toward preventing brain injuries.