Optic nerve sheath diameter measured sonographically as non-invasive estimator of intracranial pressure: a systematic review and meta-analysis

The Effect of Different Optic Nerve Sheath Diameter Measurements Using Ultrasound to Assess Intracranial Pressure in Patients With Acute Brain Injury

BACKGROUND

Optic nerve sheath diameter (ONSD) is a promising, noninvasive invasive intracranial pressure (ICP) measurement method. This study aims to analyze the differences in ONSD between the left and right eyeballs and the differences in ultrasonic measurement between the transverse and sagittal planes.

METHODS

Data from a total of 50 eligible patients with various types of brain injury who were admitted to our hospital from May 2019 to June 2021 were analyzed. An ONSD assessment was then performed using Philips B-mode ultrasound, measuring ONSD 3 mm posterior to the eyeballs. The left and right ONSDs in the transverse and sagittal planes were measured. Intraparenchymal fiber optic sensors and catheters were inserted into the ventricles and connected to an external pressure transducer to measure ICP.

RESULTS

A total of 164 sonographic measurements of ONSD were performed in 50 patients with brain injury in a prospective observational study. Statistically significant differences were found in ONSD between the transverse and sagittal planes. The difference in the left ONSD between the transverse and sagittal planes was 0.007 ± 0.030 cm ( P = 0.003). The Spearman rank correlation test showed that the correlation coefficient between ICP and left/right ONSD in the transverse/sagittal planes was 0.495 vs 0.546 and 0.559 vs 0.605, respectively. The results showed that the areas under the curve of ONSD in the transverse and sagittal planes were 0.843 and 0.805, respectively. Medcalc software was used to compare the areas under the receiver operator characteristic curve, and the results showed that ONSD in the sagittal plane is generally better than in the transverse plane ( P = 0.0145).

CONCLUSIONS

This study found that ONSD in the sagittal plane is superior to the transverse plane regarding the comprehensive efficacy of ICP, and unilateral measurement is sufficient.

Using Optic Nerve Sheath Diameter for Intracranial Pressure (ICP) Monitoring in Traumatic Brain Injury: A Scoping Review

INTRODUCTION

Neuromonitoring represents a cornerstone in the comprehensive management of patients with traumatic brain injury (TBI), allowing for early detection of complications such as increased intracranial pressure (ICP) [1]. This has led to a search for noninvasive modalities that are reliable and deployable at bedside. Among these, ultrasonographic optic nerve sheath diameter (ONSD) measurement is a strong contender, estimating ICP by quantifying the distension of the optic nerve at higher ICP values. Thus, this scoping review seeks to describe the existing evidence for the use of ONSD in estimating ICP in adult TBI patients as compared to gold-standard invasive methods.

MATERIALS AND METHODS

This review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, with a main search of PubMed and EMBASE. The search was limited to studies of adult patients with TBI published in any language between 2012 and 2022. Sixteen studies were included for analysis, with all studies conducted in high-income countries.

RESULTS

All of the studies reviewed measured ONSD using the same probe frequency. In most studies, the marker position for ONSD measurement was initially 3 mm behind the globe, retina, or papilla. A few studies utilized additional parameters such as the ONSD/ETD (eyeball transverse diameter) ratio or ODE (optic disc elevation), which also exhibit high sensitivity and reliability.

CONCLUSION

Overall, ONSD exhibits great test accuracy and has a strong, almost linear correlation with invasive methods. Thus, ONSD should be considered one of the most effective noninvasive techniques for ICP estimation in TBI patients.

Cerebral hemodynamics and optic nerve sheath diameter acquired via neurosonology in critical patients with severe coronavirus disease: experience of a national referral hospital in Peru

Aim

We aimed to describe the neurosonological findings related to cerebral hemodynamics acquired using transcranial Doppler and to determine the frequency of elevated ICP by optic nerve sheath diameter (ONSD) measurement in patients with severe coronavirus disease (COVID-19) hospitalized in the intensive care unit of a national referral hospital in Peru.

Methods

We included a retrospective cohort of adult patients hospitalized with severe COVID-19 and acute respiratory failure within the first 7 days of mechanical ventilation under deep sedoanalgesia, with or without neuromuscular blockade who underwent ocular ultrasound and transcranial Doppler. We determine the frequency of elevated ICP by measuring the diameter of the optic nerve sheath, choosing as best cut-off value a diameter equal to or >5.8 mm. We also determine the frequency of sonographic patterns obtained by transcranial Doppler. Through insonation of the middle cerebral artery. Likewise, we evaluated the associations of clinical, mechanical ventilator, and arterial blood gas variables with ONSD ≥5.8 mm and pulsatility index (PI) ≥1.1. We also evaluated the associations of hemodynamic findings and ONSD with mortality the effect size was estimated using Poisson regression models with robust variance.

Results

This study included 142 patients. The mean age was 51.39 ± 13.3 years, and 78.9% of patients were male. Vasopressors were used in 45.1% of patients, and mean arterial pressure was 81.87 ± 10.64 mmHg. The mean partial pressure of carbon dioxide (PaCO2) was elevated (54.08 ± 16.01 mmHg). Elevated intracranial pressure was seen in 83.1% of patients, as estimated based on ONSD ≥5.8 mm. A mortality rate of 16.2% was reported. In the multivariate analysis, age was associated with elevated ONSD (risk ratio [RR] = 1.07). PaCO2 was a protective factor (RR = 0.64) in the cases of PI ≥ 1.1. In the mortality analysis, the mean velocity was a risk factor for mortality (RR = 1.15).

Conclusions

A high rate of intracranial hypertension was reported, with ONSD measurement being the most reliable method for estimation. The increase in ICP measured by ONSD in patients with severe COVID-19 on mechanical ventilation is not associated to hypercapnia or elevated intrathoracic pressures derived from protective mechanical ventilation.

The Effect of Hydrocephalus on the Optic Nerve in the Presence of Intracranial Mass

OBJECTIVE

The measurement of optic nerve sheath diameter is a noninvasive, practical, and economical method used to identify increased intracranial pressure. The purpose of this study is to detect the preoperative and postoperative changes in optic nerve sheath diameter in patients with intracranial mass, to correlate these changes with optic nerve diameter variations, and to evaluate the impact of hydrocephalus on these alterations.

MATERIAL AND METHOD

This study was conducted with patients who presented to our clinic with complaints of intracranial mass, were decided for surgery, and underwent surgical procedures.

FINDINGS

The optic nerve and optic nerve sheath diameter measurement values were different preoperatively and postoperatively, with a significant decrease in the optic nerve sheath diameter in all groups in postoperative measurements, while the optic nerve diameter significantly increased.

CONCLUSIONS

Although there was no significant difference between the effects of hydrocephalus and intracranial mass-related increase in intracranial pressure on the optic nerve and optic nerve sheath, it was observed that hydrocephalus increased intracranial pressure when considering the Evans ratio. It has been determined that as ventricular dilatation increases, so does intracranial pressure, which leads to an increase in the diameter of the optic nerve sheath, resulting in papilledema and thinning of the optic nerve. These findings indicate the importance of early cerebrospinal fluid diversion and monitoring optic nerve sheath diameter in the management.

The Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome is a syndrome of increased cerebrospinal fluid pressure without ventriculomegaly, mass lesion, or meningeal abnormality. It is either primary (idiopathic intracranial hypertension, IIH) or secondary. A secondary cause is unlikely when adhering to the diagnostic criteria. Permanent visual loss occurs if undetected or untreated, and the associated headaches may be debilitating. Fulminant disease may result in blindness despite aggressive treatment. This study addresses the diagnosis and management of IIH including new insights into the pathobiology of IIH, updates in therapeutics and causes of overdiagnosis.

Terson Syndrome Diagnosed by Ocular Point of Care Ultrasound on the Medical Floor

In acute care environments, accurately assessing complications of intracranial pathology can be challenging. Ocular complications in acute intracranial disease are not consistently evaluated despite their high morbidity. We report on a case of monocular diplopia in a 63-year-old man with subacute traumatic brain injury with localized subarachnoid hemorrhage. Ocular point of care ultrasound (POCUS) identified features of vitreous hemorrhage in one globe, leading to a diagnosis of Terson syndrome and a timely referral to ophthalmology. This finding was made on the medical floor days after the initial presentation during rehabilitation when ophthalmoscopy was not possible, and vitreous hemorrhage had not been identified on presentation. Terson syndrome is a seldom discussed but important complication of intracranial hemorrhage generally associated with poor patient outcomes. Ocular POCUS can provide a useful alternative in assessing ocular complications of acute intracranial disease on the medical floor, particularly when the practicalities of performing ophthalmoscopy are challenged.

A Narrative Review on Financial Challenges and Health Care Costs Associated with Traumatic Brain Injury in the United States

BACKGROUND

Traumatic brain injury (TBI) is a highly prevalent and potentially severe medical condition. Challenges regarding TBI management are related to accurate diagnostics, defining its severity, and establishing prompt interventions to affect outcomes. Among the health care components in the TBI handling strategy is intracranial pressure (ICP) monitoring, which is fundamental to therapy decisions. However, ICP monitoring is an Achilles tendon, imposing a significant financial burden on health care systems, particularly in middle and low-income communities. This article arises from the understanding from the authors that there is insufficient scientific evidence about the potential economic impacts from the use of noninvasive technologies in the monitoring of TBI. Based on personal experience, as well as from reading other, clinically focused studies, the thesis is that the use of such technologies could greatly affect the health care system and this article seeks to address this lack of literature, show ways in which such systems could be evaluated, and show estimations of possible results from these investigations.

OBJECTIVE

This review primarily investigates the economic burden of TBI and whether new technologies are suitable to reduce its health care costs without compromising the quality of care, according to the levels of evidence available. The objective is to stimulate more research and attention in the area.

METHODS

For this narrative review, a PubMed search was conducted for articles discussing TBI health care costs, as well as monitoring technologies (tomography, magnetic resonance imaging, optic nerve sheath diameter, transcranial Doppler, pupillometry, and noninvasive ICP waveform) and their application in managing TBI. Strategies were first evaluated from a medical noninferiority perspective before calculating the average savings of each selected strategy. All applicable studies were analyzed for quality using the Consolidated Health Economic Evaluation Reporting Standards 2022 Statement117 and this article was written to conform as much as possible with it.

RESULTS

The review included 109 references and showed a consistent potential in noninvasive technologies to reduce costs and maintain or improve the quality of care.

CONCLUSIONS

TBI prevalence has increased with a disproportionate health care burden in the last decades. Noninvasive monitoring techniques seem to be effective in reducing TBI health care costs, with few limitations, especially the need for more supporting scientific evidence. The undeniable clinical and financial potential of these techniques is compelling to further investigate their role in TBI management, as well as the creation of more comprehensive monitoring models to the understanding of complex phenomena occurring in the injured brain.

"NeuroVanguard": a contemporary strategy in neuromonitoring for severe adult brain injury patients

Severe acute brain injuries, stemming from trauma, ischemia or hemorrhage, remain a significant global healthcare concern due to their association with high morbidity and mortality rates. Accurate assessment of secondary brain injuries severity is pivotal for tailor adequate therapies in such patients. Together with neurological examination and brain imaging, monitoring of systemic secondary brain injuries is relatively straightforward and should be implemented in all patients, according to local resources. Cerebral secondary injuries involve factors like brain compliance loss, tissue hypoxia, seizures, metabolic disturbances and neuroinflammation. In this viewpoint, we have considered the combination of specific noninvasive and invasive monitoring tools to better understand the mechanisms behind the occurrence of these events and enhance treatment customization, such as intracranial pressure monitoring, brain oxygenation assessment and metabolic monitoring. These tools enable precise intervention, contributing to improved care quality for severe brain injury patients. The future entails more sophisticated technologies, necessitating knowledge, interdisciplinary collaboration and resource allocation, with a focus on patient-centered care and rigorous validation through clinical trials.

Moderate Traumatic Brain Injury in Adult Population: The Latin American Brain Injury Consortium Consensus for Definition and Categorization

Moderate traumatic brain injury (TBI) is a diagnosis that describes diverse patients with heterogeneity of primary injuries. Defined by a Glasgow Coma Scale between 9 and 12, this category includes patients who may neurologically worsen and require increasing intensive care resources and/or emergency neurosurgery. Despite the unique characteristics of these patients, there have not been specific guidelines published before this effort to support decision-making in these patients. A Delphi consensus group from the Latin American Brain Injury Consortium was established to generate recommendations related to the definition and categorization of moderate TBI. Before an in-person meeting, a systematic review of the literature was performed identifying evidence relevant to planned topics. Blinded voting assessed support for each recommendation. A priori the threshold for consensus was set at 80% agreement. Nine PICOT questions were generated by the panel, including definition, categorization, grouping, and diagnosis of moderate TBI. Here, we report the results of our work including relevant consensus statements and discussion for each question. Moderate TBI is an entity for which there is little published evidence available supporting definition, diagnosis, and management. Recommendations based on experts' opinion were informed by available evidence and aim to refine the definition and categorization of moderate TBI. Further studies evaluating the impact of these recommendations will be required.

Noninvasive Assessment of Intracranial Pressure: Deformability Index as an Adjunct to Optic Nerve Sheath Diameter to Increase Diagnostic Ability

BACKGROUND

Today, invasive intracranial pressure (ICP) measurement remains the standard, but its invasiveness limits availability. Here, we evaluate a novel ultrasound-based optic nerve sheath parameter called the deformability index (DI) and its ability to assess ICP noninvasively. Furthermore, we ask whether combining DI with optic nerve sheath diameter (ONSD), a more established parameter, results in increased diagnostic ability, as compared to using ONSD alone.

METHODS

We prospectively included adult patients with traumatic brain injury with invasive ICP monitoring, which served as the reference measurement. Ultrasound images and videos of the optic nerve sheath were acquired. ONSD was measured at the bedside, whereas DI was calculated by semiautomated postprocessing of ultrasound videos. Correlations of ONSD and DI to ICP were explored, and a linear regression model combining ONSD and DI was compared to a linear regression model using ONSD alone. Ability of the noninvasive parameters to distinguish dichotomized ICP was evaluated using receiver operating characteristic curves, and a logistic regression model combining ONSD and DI was compared to a logistic regression model using ONSD alone.

RESULTS

Forty-four ultrasound examinations were performed in 26 patients. Both DI (R =  - 0.28; 95% confidence interval [CI] R <  - 0.03; p = 0.03) and ONSD (R = 0.45; 95% CI R > 0.23; p < 0.01) correlated with ICP. When including both parameters in a combined model, the estimated correlation coefficient increased (R = 0.51; 95% CI R > 0.30; p < 0.01), compared to using ONSD alone, but the model improvement did not reach statistical significance (p = 0.09). Both DI (area under the curve [AUC] 0.69, 95% CI 0.53-0.83) and ONSD (AUC 0.72, 95% CI 0.56-0.86) displayed ability to distinguish ICP dichotomized at ICP ≥ 15 mm Hg. When using both parameters in a combined model, AUC increased (0.80, 95% CI 0.63-0.90), and the model improvement was statistically significant (p = 0.02).

CONCLUSIONS

Combining ONSD with DI holds the potential of increasing the ability of optic nerve sheath parameters in the noninvasive assessment of ICP, compared to using ONSD alone, and further study of DI is warranted.

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.

Transcranial sonography in the critical patient

Transcranial ultrasonography is a non-invasive, bedside technique that has become a widely implemented tool in the evaluation and management of neurocritically ill patients. It constitutes a technique in continuous growth whose fundamentals (and limitations) must be known by the intensivist. This review provides a practical approach for the intensivist, including the different sonographic windows and planes of insonation and its role in different conditions of the neurocritical patients and in critical care patients of other etiologies.

A pilot clinical study to estimate intracranial pressure utilising cerebral photoplethysmograms in traumatic brain injury patients

PURPOSE

In this research, a non-invasive intracranial pressure (nICP) optical sensor was developed and evaluated in a clinical pilot study. The technology relied on infrared light to probe brain tissue, using photodetectors to capture backscattered light modulated by vascular pulsations within the brain's vascular tissue. The underlying hypothesis was that changes in extramural arterial pressure could affect the morphology of recorded optical signals (photoplethysmograms, or PPGs), and analysing these signals with a custom algorithm could enable the non-invasive calculation of intracranial pressure (nICP).

METHODS

This pilot study was the first to evaluate the nICP probe alongside invasive ICP monitoring as a gold standard. nICP monitoring occurred in 40 patients undergoing invasive ICP monitoring, with data randomly split for machine learning. Quality PPG signals were extracted and analysed for time-based features. The study employed Bland-Altman analysis and ROC curve calculations to assess nICP accuracy compared to invasive ICP data.

RESULTS

Successful acquisition of cerebral PPG signals from traumatic brain injury (TBI) patients allowed for the development of a bagging tree model to estimate nICP non-invasively. The nICP estimation exhibited 95% limits of agreement of 3.8 mmHg with minimal bias and a correlation of 0.8254 with invasive ICP monitoring. ROC curve analysis showed strong diagnostic capability with 80% sensitivity and 89% specificity.

CONCLUSION

The clinical evaluation of this innovative optical nICP sensor revealed its ability to estimate ICP non-invasively with acceptable and clinically useful accuracy. This breakthrough opens the door to further technological refinement and larger-scale clinical studies in the future.

TRIAL REGISTRATION

NCT05632302, 11th November 2022, retrospectively registered.

Optic nerve sheath diameter measurements to predict delayed neurological sequelae after carbon monoxide poisoning

OBJECTIVES

Delayed neurological sequelae are a major complication of carbon monoxide poisoning. However, today there is still no objective screening tool for predicting delayed neurological sequelae in patients with carbon monoxide poisoning. The present study aimed to assess the usefulness of optic nerve sheath diameter measurements in predicting delayed neurological sequelae after carbon monoxide poisoning.

METHODS

In this retrospective study, patients with a diagnosis of carbon monoxide poisoning in the emergency department from 2010 to 2021 were included in the study. Right and left optic nerve sheath diameters were calculated based on cranial computed tomography scans, and the presence of delayed neurological sequelae was evaluated.

RESULTS

The mean (± standard deviation) optic nerve sheath diameter in patients who developed delayed neurological sequelae was statistically significantly greater on both the right and left compared to patients who did not develop delayed neurological sequelae (right; 5.02 ± 0.06 mm versus 4.89 ± 0.07 mm, P < 0.001; left; 5.03 ± 0.09 mm versus 4.85 ± 0.10 mm, P < 0.001). A multivariate linear regression analysis revealed that carboxyhemoglobin and both right and left optic nerve sheath diameter were the factors associated with the delayed neurological sequelae.

DISCUSSION

The present study revealed that optic nerve sheath diameter measurements may be a useful screening tool to predict delayed neurological sequelae after carbon monoxide poisoning. The ability to predict a poor neurological prognosis in carbon monoxide poisoning is important for initiating early rehabilitation interventions and make help future trials. Limitations of this study include that normal optic nerve sheath diameters are not well established, and that not every patient underwent computed tomography.

CONCLUSIONS

Optic nerve sheath diameters measurements may be a helpful screening tool for predicting delayed neurological sequelae after carbon monoxide poisoning.

Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis

OBJECTIVES

Timely diagnosis and management of elevated intracranial pressure (ICP) in patients with traumatic brain injury (TBI) can significantly reduce mortality rates. Ultrasound examination of the optic nerve sheath diameter (ONSD) is considered a potential, noninvasive, and effective method for assessing ICP. We conducted a systematic review and meta-analysis of ONSD ultrasound detection and invasive ICP monitoring methods to compare and evaluate the diagnostic accuracy of ONSD ultrasound detection methods for intracranial hypertension (IH) in patients with TBI.

METHODS

We searched the Web of Science, PubMed, and Embase databases to assess the diagnostic accuracy of ONSD sonography for predicting increased ICP. The 2 authors independently extracted the collected data. Simultaneously, the QUADAS-2 tool was used to evaluate the bias risk of each study and conducted random-effects meta-analyses for the accuracy and specificity of diagnosis, and calculated pooled estimates.

RESULTS

Ten studies with 512 patients were included. The diagnostic accuracy of ONSD sonography for IH was revealed as a pooled sensitivity of 0.85 (95% confidence interval [CI], 0.79-0.89) and specificity of 0.88 (95% CI, 0.80-0.93), compared with the invasive ICP monitoring standard for patients with TBI.

CONCLUSIONS

ONSD sonography may be a useful method for predicting increased ICP in adult patients with TBI. Further clinical studies are required to confirm the diagnostic value of ONSD sonography.

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.

Ultrasonic optic nerve sheath diameter can be used as a diagnostic measure after accidental dural puncture during cesarean section: a case report

BACKGROUND

Parturients are prone to postdural puncture headache (PDPH) after epidural puncture. Cerebral venous sinus thrombosis (CVST) is a fatal complication of PDPH. The main symptom of both is headache, however, the mechanism is not similar. For persistent PDPH, early differential diagnosis from CVST is essential. Optic nerve sheath diameter (ONSD) measurements can be used to identify changes in intracranial pressure as an auxiliary tool to distinguish the cause of headache.

CASE PRESENTATION

The dura of a 32-year-old woman undergoing cesarean section was accidentally penetrated while administering epidural anesthesia, and the patient developed PDPH the subsequent day. The patient refused epidural blood patch (EBP) treatment and was discharged after conservative treatment. Fourteen days post-discharge, she was readmitted for a seizure. Magnetic resonance imaging (MRI) and Magnetic resonance angiography (MRA) indicated low cranial pressure syndrome and superior sagittal sinus thrombosis with acute infarction. The next morning, the EBP was performed with 15 ml autologous blood. Subsequently, the headache symptoms decreased during the day and worsened at night. ONSD measurement suggested dilation of the optic nerve sheath, and subsequently, the patient showed intracranial hypertension with papilledema. After dehydration and anticoagulant treatment, the patient's symptoms were relieved and she was discharged from the hospital 49 days later.

CONCLUSIONS

Headache is the main symptom of PDPH and cerebral venous thrombosis, which are difficult to distinguish. ONSD measurement may help to estimate the intracranial pressure, and early measurement may be helpful for women with PDPH to avoid serious complications, such as CVST.

Severe osmotic demyelination syndrome with cortical involvement in the context of severe hyponatremia and central diabetes insipidus: an uncommon presentation of an unusual combination

BACKGROUND

Osmotic demyelination syndrome (ODS) with cerebral cortical involvement is a rare complication of severe hyponatremia correction. Careful management of hyponatremia is crucial, particularly in patients with risk factors, such as alcohol use disorder and diabetes insipidus.

CASE

A patient in his 40s with a history of alcohol use disorder and central diabetes insipidus developed ODS after a 24 mEq/L osmolar increase during the treatment of hyponatremia. The patient's condition progressed into locked-in syndrome and then improved to spastic tetraparesis after cortical basal ganglia ODS improved.

DISCUSSION

The differential diagnosis of cortical demyelination includes laminar cortical necrosis, being the interpretation of Apparent Diffusion Coefficient (ADC) MRI sequence is a useful tool.This case underscores the need to investigate and improve diagnosis and treatment strategies in patients with ODS. It also emphasises the significance of careful hyponatremia correction and frequent monitoring, particularly in patients with known risk factors for ODS.

A Novel Method for Prediction of Raised Intracranial Pressure Through Automated ONSD and ETD Ratio Measurement From Ocular Ultrasound

The paper presents a novel framework for the prediction of the raised Intracranial Pressure (ICP) from ocular ultrasound images of traumatic patients through automated measurement of Optic Nerve Sheath Diameter (ONSD) and Eyeball Transverse Diameter (ETD). The measurement of ONSD using an ocular ultrasound scan is non-invasive and correlates with the raised ICP. However, the existing studies suggested that the ONSD value alone is insufficient to indicate the ICP condition. Since the ONSD and ETD values may vary among patients belonging to different ethnicity/origins, there is a need for developing an independent global biomarker for predicting raised ICP condition. The proposed work develops an automated framework for the prediction of raised ICP by developing algorithms for the automated measurement of ONSD and ETD values. It is established that the ONSD and ETD ratio (OER) is a potential biomarker for ICP prediction independent of ethnicity and origin. The OER threshold value is determined by performing statistical analysis on the data of 57 trauma patients obtained from the AIIMS, New Delhi. The automated OER is computed and compared with the conventionally measured ICP by determining suitable correlation coefficients. It is found that there is a significant correlation of OER with ICP (r = .81, p ≤ .01), whereas the correlation of ONSD alone with ICP is relatively less (r = .69, p = .004). These correlation values indicate that OER is a better parameter for the prediction of ICP. Further, the threshold value of OER is found to be 0.21 for predicting raised ICP conditions in this study. Scatter plot and Heat map analysis of OER and corresponding ICP reveal that patients with OER ≥ 0.21, have ICP in the range of 17 to 35 mm Hg. In the data available for this research work, OER ranges from 0.17 to 0.35.

A glimpse into multimodal neuromonitoring in acute liver failure: a case report

Introduction

Acute liver failure (ALF) is a rapidly progressing, life-threatening syndrome characterized by liver-related coagulopathy and hepatic encephalopathy (HE). Given that higher HE grades correlate with poorer outcomes, clinical management of ALF necessitates close neurological monitoring. The primary objective of this case report is to highlight the diagnostic value of utilizing multimodal neuromonitoring (MNM) in a patient suffering from ALF.

Case report

A 56-year-old male patient with a history of chronic alcoholism, without prior chronic liver disease, and recent acetaminophen use was admitted to the hospital due to fatigue and presenting with a mild flapping tremor. The primary hypothesis was an acute hepatic injury caused by acetaminophen intoxication. In the following hours, the patient's condition deteriorated, accompanied by neurological decline and rising ammonia levels. The patient's neurological status was closely monitored using MNM. Bilaterally altered pupillary light reflex assessed by decreasing in the Neurological Pupil Index values, using automated pupillometry, initially suggested severe brain oedema. However, ultrasound measurements of the optic nerve sheath diameter showed normal values in both eyes, P2/P1 noninvasive intracranial pressure waveform assessment was within normal ranges and the cerebral computed tomography-scan revealed no signs of cerebral swelling. Increased middle cerebral artery velocities measured by Transcranial Doppler and the initiation of electroencephalography monitoring yielded the presence of status epilepticus.

Discussion

The utilization of MNM facilitated a more comprehensive understanding of the mechanisms underlying the patient's clinical deterioration in the setting of HE. Nonetheless, future studies are needed to show feasibility and to yield valuable insights that can enhance the outcomes for patients with HE using such an approach. Given the absence of specific guidelines in this particular context, it is advisable for physicians to give further consideration to the incorporation of MNM in the management of unconscious patients with ALF.

Transorbital sonography in idiopathic intracranial hypertension: Single-center study, systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transorbital sonography (TOS) provides a noninvasive tool to detect intracranial pressure by assessing optic nerve sheath diameter (ONSD) and optic disc elevation (ODE). The utility of TOS in the diagnosis of idiopathic intracranial hypertension (IIH) has been increasingly recognized.

METHODS

A single-center case-control study sought to compare TOS-acquired ONSD and ODE among IIH-cases versus patients with other neurological diseases (controls). Furthermore, a systematic review and meta-analysis was conducted to present pooled mean differences and diagnostic measures of ONSD and ODE between IIH-cases and controls.

RESULTS

In the single-center study, consisting of 31 IIH-cases and 34 sex- and age-matched controls, ONSD values were higher among IIH-cases than controls (p<.001), while ODE was more prevalent in cases (65% vs. 15%; p<.001). The receiver-operating characteristic (ROC)-curve analysis revealed that the optimal cutoff value of ONSD for predicting IIH was 5.15 mm, with an area under the curve (AUC) of 0.914 (95% confidence interval [CI]: 0.861-0.967) and sensitivity and specificity values of 85% and 90%, respectively. In a meta-analysis of 14 included studies with 415 IIH-cases, ONSD and ODE values were higher in IIH-cases than controls (mean difference in ONSD 1.20 mm; 95% CI: 0.96-1.44 mm and in ODE 0.3 mm; 95% CI: 0.33-0.67 mm). With regard to ONSD, pooled sensitivity, specificity, and diagnostic odds ratio were calculated at 85.5% (95% CI: 77.9-90.8%), 90.7% (95% CI: 84.6-94.5%), and 57.394 (95% CI: 24.597-133.924), respectively. The AUC in summary ROC-curve analysis was 0.878 (95% CI: 0.858-0.899) with an optimal cutoff point of 5.0 mm.

CONCLUSIONS

TOS has a high diagnostic utility for the noninvasive diagnosis of IIH and may deserve wider implementation in everyday clinical practice.

Measurement of Optic Nerve Sheath Diameter by Computed Tomography in the Pediatric Population: Normal Values

PURPOSE

To determine the normal values of optic nerve sheath diameter (ONSD) by computed tomography (CT) in the pediatric population.

METHODS

The CT scans of pediatric patients aged 1 to 16 years who underwent brain CT for different reasons, who did not have intracranial pathology or increased intracranial pressure, and who had no pathology on CT were included in the study. Four age groups were defined with the following ranges: 1 to 2, 3 to 6, 7 to 10, and 11 to 16 years. ONSD was measured from axial CT images, 3 and 10 mm behind the optic globe.

RESULTS

The normative values of ONSD measured on CT imaging in children aged 1 to 16 years were reported. The change in ONSD according to age was investigated. ONSD was found to increase with age at both levels measured. The difference was statistically significant.

CONCLUSIONS

Normal values should be known to detect pathologies that may cause an increase in optic nerve diameter. The values reported in this study can serve as a reference for normal optic nerve sheath diameter in the pediatric age group. [J Pediatr Ophthalmol Strabismus. 2024;61(1):38-43.].

Evidence-based management of adult traumatic brain injury with raised intracranial pressure in intensive critical care unit at resource-limited settings: a literature review

Background

In underdeveloped countries, there is a greater incidence of mortality and morbidity arising from trauma, with traumatic brain injury (TBI) accounting for 50% of all trauma-related deaths. The occurrence of elevated intracranial pressure (ICP), which is a common pathophysiological phenomenon in cases of TBI, acts as a contributing factor to unfavorable outcomes. The aim of this systematic review is to analyze the existing literature regarding the management of adult TBI with raised ICP in an intensive critical care unit, despite limited resources.

Methods

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis protocol. Search engines such as PubMed, the Cochrane database, and Google Scholar were utilized to locate high-level evidence that would facilitate the formation of sound conclusions.

Result

A total of 11 715 articles were identified and individually assessed to determine their eligibility for inclusion or exclusion based on predetermined criteria and outcome variables. The methodological quality of each study was evaluated using recommended criteria. Ultimately, the review consisted of 51 articles.

Conclusion

Physical examination results and noninvasive assessments of the optic nerve sheath diameter (ONSD) via sonography are positively associated with elevated ICP, and are employed as diagnostic and monitoring tools for elevated ICP in resource-limited settings. Management of elevated ICP necessitates an algorithmic approach that utilizes prophylactic measures and acute intervention treatments to mitigate the risk of secondary brain injury.

Diagnostic accuracy of optic nerve sheath diameter on ultrasound for the detection of increased intracranial pressure in patients with traumatic brain injury: A systematic review and meta‑analysis

The timely diagnosis and treatment of elevated intracranial pressure (ICP) reduces morbidity rates and prevents mortality. The aim of the present systematic review and meta-analysis was to determine the diagnostic accuracy of optic nerve sheath diameter (ONSD) vs. standard invasive ICP measurements in patients with traumatic brain injury (TBI). The PubMed, Embase, Web of Science and Cochrane Library databases were systematically searched for studies including adult patients with TBI with suspected elevated ICP, and the sonographic ONSD measurements were compared with those from a standard invasive method. The quality of the studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool by two independent authors. A bivariate random effects model was used to summarize the pooled sensitivity, specificity and diagnostic odds ratio (DOR). A total of eight prospective studies with 222 patients with TBI were included. The pooled sensitivity was 0.82 [95% confidence interval (CI), 0.75-0.88], the specificity was 0.82 (95% CI, 0.71-0.90) and the DOR was 17.75 (95% CI, 7.02-44.83) with partial evidence of heterogeneity. The accuracy of the area under the summary ROC was 0.87. An ultrasound-determined elevated ICP has reasonable performance indicators with high sensitivity and specificity in patients with TBI. As such, this method may be a useful complementary monitoring tool in acute care.

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.

The role of optic nerve sheath ultrasonography in increased intracranial pressure: A systematic review and meta analysis

OBJECTIVES

To review the optimal diagnostic cut-off of ultrasonographic optic nerve sheath diameter (ONSD) in the diagnosis of increased intracranial pressure (IICP).

METHODS

A systematic search was conducted of available studies assessing the use of ONSD ultrasonography in patients with suspected IICP. Meta-analysis of diagnostic accuracy of ultrasonographic ONSD was performed using a bivariate model of random effects to summarize pooled sensitivity and specificity. A summary receiver operating characteristics (SROC) curve was plotted. Accuracy measures associated with ONSD cut-off and predefined covariates were investigated with meta-regression.

RESULTS

We included 38 studies, comprising a total of 2824 patients. A total of 21 studies used invasive techniques as a reference standard estimation of IICP and meta-analysis revealed a pooled sensitivity of 0.90 (95% CI 0.85-0.93) and specificity of 0.87 (95% CI 0.80-0.91). Optimal ONSD cut-off values ranged between 4.1 mm and 7.2 mm. Meta-regression analysis showed that ONSD cut-off values of 5.6 to 6.3 mm were associated with higher pooled specificity compared to cut-off values of 4.9 to 5.5 mm (0.93, 95% CI 0.85-0.97 vs. 0.78, 95% CI 0.65-0.87; p = 0.036).

CONCLUSIONS

Ultrasonography of ONSD shows a high diagnostic accuracy for IICP, with high pooled sensitivity and specificity. Additionally, larger cut-off values seem to significantly increase specificity without compromising sensitivity, which support their use as optimal ONSD cut-off. The overall high sensitivity of ultrasonographic ONSD suggests its usefulness as a screening tool for IIC, which may provide an estimate of when invasive methods are warranted.

CLINICAL RELEVANCE

ONSD ultrasonography is a fast and cost-effective method with a high diagnostic accuracy to detect IICP. The optimum ONSD cut-off hasn't been established before, but we suggest the 5.6 to 6.3 mm range as the best for the diagnosis of IICP.

Automation of ultrasonographic optic nerve sheath diameter measurement using convolutional neural networks

BACKGROUND AND PURPOSE

Ultrasonographic optic nerve sheath (ONS) diameter is a noninvasive intracranial pressure (ICP) surrogate. ICP is monitored invasively in specialized intensive care units. Noninvasive ICP monitoring is important in less specialized settings. However, noninvasive ICP monitoring using ONS diameter (ONSD) is limited by the need for experts to obtain and perform measurements. We aim to automate ONSD measurements using a deep convolutional neural network (CNN) with a novel masking technique.

METHODS

We trained a CNN to reproduce masks that mark the ONS. The edges of the mask are defined by an expert. Eight models were trained with 1000 epochs per model. The Dice-similarity-coefficient-weighted averaged outputs of the eight models yielded the final predicted mask. Eight hundred and seventy-three images were obtained from 52 transorbital cine-ultrasonography sessions, performed on 46 patients with brain injuries. Eight hundred and fourteen images from 48 scanning sessions were used for training and validation and 59 images from four sessions for testing. Bland-Altman and Pearson linear correlation analyses were used to evaluate the agreement between CNN and expert measurements.

RESULTS

Expert ONSD measurements and CNN-derived ONSD estimates had strong agreement (r = 0.7, p < .0001). The expert mean ONSD (standard deviation) is 5.27 mm (0.43) compared to CNN mean estimate of 5.46 mm (0.37). Mean difference (95% confidence interval, p value) is 0.19 mm (0.10-0.27 mm, p = .0011), and root mean square error is 0.27 mm.

CONCLUSION

A CNN can learn ONSD measurement using masking without image segmentation or landmark detection.

Association between optic nerve sheath diameter/eyeball transverse diameter ratio and neurological outcomes in patients with aneurysmal subarachnoid hemorrhage

OBJECTIVE

The optic nerve sheath diameter (ONSD)/eyeball transverse diameter (ETD) ratio is a more reliable marker of intracranial pressure than the ONSD alone. We aimed to investigate the predictive value of the ONSD/ETD ratio (OER) for neurological outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

Adult patients with aSAH who visited the emergency department of a tertiary hospital connected to a South Korean university between January 2015 and December 2021 were included. Data on patient characteristics and brain computed tomography scan findings, including the ONSD and ETD, were collected using a predefined protocol. According to the neurological outcome at hospital discharge, the patients were divided into the unfavorable neurological outcome (UNO; cerebral performance category [CPC] score 3-5) and the favorable neurological outcome (FNO; CPC score 1-2) groups. The primary outcome was the association between the OER and neurological outcomes in patients with aSAH.

RESULTS

A total of 171 patients were included in the study, of whom 118 patients (69%) had UNO. Neither the ONSD (p=0.075) nor ETD (p=0.403) showed significant differences between the two groups. However, the OER was significantly higher in the UNO group in the univariate analysis (p=0.045). The area under the receiver operating characteristic curve of the OER for predicting UNO was 0.603 (p=0.031). There was no independent relationship between the OER and UNO in the multivariate logistic regression analysis (adjusted odds ratio, 0.010; p=0.576).

CONCLUSION

The OER was significantly higher in patients with UNO than in those with FNO, and the OER was more reliable than the ONSD alone. However, the OER had limited utility in predicting UNO in patients with aSAH.

Non-invasive intracranial pressure estimation using ultrasonographic measurement of area of optic nerve subarachnoid space

OBJECTIVE

To verify whether the area of the ONSAS (ONSASA) obtained by transorbital ultrasonography can be used to accurately evaluate the intracranial pressure (ICP).

METHODS

The recorded indexes included the optic nerve diameter, the optic nerve sheath diameter (ONSD), the width of both sides of the ONSAS (ONSASW) at 3 mm from the optic nerve head and the entire ONSASA outlined between 3 and 7 mm. After exploring and comparing five models to describe the relationship between body mass index (BMI), mean arterial blood pressure (MABP), ONSASA and ICP, the best model was determined.

RESULTS

In all, 90 patients with neurological diseases undergoing continuous invasive ICP monitoring were included in the study. In the training group, the correlation coefficient for the association between the ICP and ONSASA (Pearson's correlation r=0.953) was higher than that for the association of the ICP with the ONSD (r=0.672; p<0.0001) and ONSASW at 3 mm behind the globe (r=0.691; p<0.0001). In the training group, the weighting function for prediction of the ICP was as follows: non-invasive ICP=2.050×ONSASA-0.051×BMI +0.036*MABP-5.837. With 20 mm Hg as the cut-off point for a high or low ICP, the sensitivity and specificity of ONSASA predicting ICP was 1.00 and 0.92. Receiver operator curve analysis revealed that the calculated cut-off value for predicting elevated ICP was 19.96 (area under curve= 0.960, 95% CI 0.865 to 1.00).

CONCLUSION

Measurement of the ONSASA using ultrasonography can serve as a practical method for rapid and non-invasive quantification for evaluating ICP through an accurate mathematical formula with the BMI and MABP considered as contributing parameters.

TRIAL REGISTRATION NUMBER

The study was registered in the Chinese Clinical Trial Registry (Study no ChiCTR2100045274).

Optic Nerve Diameter on Non-Contrast Computed Tomography and Intracranial Hypertension in Patients With Acute Brain Injury: A Validation Study

Intracranial hypertension is a feared complication of acute brain injury that can cause ischemic stroke, herniation, and death. Identifying those at risk is difficult, and the physical examination is often confounded. Given the widespread availability and use of computed tomography (CT) in patients with acute brain injury, prior work has attempted to use optic nerve diameter measurements to identify those at risk of intracranial hypertension. We aimed to validate the use of optic nerve diameter measurements on CT as a screening tool for intracranial hypertension in a large cohort of brain-injured patients. We performed a retrospective observational cohort study in a single tertiary referral Neuroscience Intensive Care Unit. We identified patients with documented intracranial pressure (ICP) measures as part of their routine clinical care who had non-contrast CT head scans collected within 24 h, and then measured the optic nerve diameters and explored the relationship and test characteristics of these measures to identify those at risk of intracranial hypertension. In a cohort of 314 patients, optic nerve diameter on CT was linearly but weakly associated with ICP. When used to identify those with intracranial hypertension (> 20 mm Hg), the area under the receiver operator curve (AUROC) was 0.68. Using a previously proposed threshold of 0.6 cm, the sensitivity was 81%, specificity 43%, positive likelihood ratio 1.4, and negative likelihood ratio 0.45. CT-derived optic nerve diameter using a threshold of 0.6 cm is sensitive but not specific for intracranial hypertension, and the overall correlation is weak.

Effects of head-down tilt on optic nerve sheath diameter in healthy subjects

PURPOSE

Intracranial pressure increases in head-down tilt (HDT) body posture. This study evaluated the effect of HDT on the optic nerve sheath diameter (ONSD) in normal subjects.

METHODS

Twenty six healthy adults (age 28 [4.7] years) participated in seated and 6° HDT visits. For each visit, subjects presented at 11:00 h for baseline seated scans and then maintained a seated or 6° HDT posture from 12:00 to 15:00 h. Three horizontal axial and three vertical axial scans were obtained at 11:00, 12:00 and 15:00 h with a 10 MHz ultrasonography probe on the same eye, randomly chosen per subject. At each time point, horizontal and vertical ONSD (mm) were quantified by averaging three measures taken 3 mm behind the globe.

RESULTS

In the seated visit, ONSDs were similar across time (p > 0.05), with an overall mean (standard deviation) of 4.71 (0.48) horizontally and 5.08 (0.44) vertically. ONSD was larger vertically than horizontally at each time point (p < 0.001). In the HDT visit, ONSD was significantly enlarged from baseline at 12:00 and 15:00 h (p < 0.001 horizontal and p < 0.05 vertical). Mean (standard error) horizontal ONSD change from baseline was 0.37 (0.07) HDT versus 0.10 (0.05) seated at 12:00 h (p = 0.002) and 0.41 (0.09) HDT versus 0.12 (0.06) seated at 15:00 h (p = 0.002); mean vertical ONSD change was 0.14 (0.07) HDT versus -0.07 (0.04) seated at 12:00 h (p = 0.02) and 0.19 (0.06) HDT versus -0.03 (0.04) seated at 15:00 h (p = 0.01). ONSD change in HDT was similar between 12:00 and 15:00 h (p ≥ 0.30). Changes at 12:00 h correlated with those at 15:00 h for horizontal (r = 0.78, p < 0.001) and vertical ONSD (r = 0.73, p < 0.001).

CONCLUSION

The ONSD increased when body posture transitioned from seated to HDT position without any further change at the end of the 3 h in HDT.

Automated pupillometry and optic nerve sheath diameter ultrasound to define tuberculous meningitis disease severity and prognosis

BACKGROUND

Tuberculous meningitis (TBM) causes high mortality and morbidity, in part due to raised intracranial pressure (ICP). Automated pupillometry (NPi) and optic nerve sheath diameter (ONSD) are both low-cost, easy-to-use and non-invasive techniques that correlate with ICP and neurological status. However, it is uncertain how to apply these techniques in the management of TBM.

METHODS

We conducted a pilot study enrolling 20 adults with TBM in the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam. Our objective was to investigate the relationships between baseline and serial measurements of NPi and ONSD and disease severity and outcome. Serial NPi and ONSD were performed for 30 days, at discharge, and at 3-months, with measurements correlated with clinical progression and outcomes.

RESULTS

ONSD and NPi measurements had an inverse relationship. Higher ONSD and lower NPi values were associated with lower Glasgow coma score. Baseline NPi was a strong predictor 3-month outcome (median NPi 4.55, interquartile range 4.35-4.65 for good outcomes versus 2.60, IQR 0.65-3.95 for poor outcomes, p = 0.002). Pupil inequality (NPi ≥0.7) was also strongly associated with poor 3-month outcomes (p = 0.006). Individual participants' serial NPi and ONSD were variable during initial treatment and correlated with clinical condition and outcome.

CONCLUSION

Pupillometry and ONSD may be used to predict clinical deterioration and outcome from TBM. Future, larger studies are need explore the optimal timing of measurements and to define how they might be used to optimise treatments and improve outcomes from TBM.

Dilated optic nerve sheath by ultrasound predicts mortality among patients with acute intracerebral hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is a deadly disease and increased intracranial pressure (ICP) is associated with worse outcomes in this context.

OBJECTIVE

We evaluated whether dilated optic nerve sheath diameter (ONSD) depicted by optic nerve ultrasound (ONUS) at hospital admission has prognostic value as a predictor of mortality at 90 days.

METHODS

Prospective multicenter study of acute supratentorial primary ICH patients consecutively recruited from two tertiary stroke centers. Optic nerve ultrasound and cranial computed tomography (CT) scans were performed at hospital admission and blindly reviewed. The primary outcome was mortality at 90-days. Multivariate logistic regression, ROC curve, and C-statistics were used to identify independent predictors of mortality.

RESULTS

Between July 2014 and July 2016, 57 patients were evaluated. Among those, 13 were excluded and 44 were recruited into the trial. Their mean age was 62.3 ± 13.1 years and 12 (27.3%) were female. On univariate analysis, ICH volume on cranial CT scan, ICH ipsilateral ONSD, Glasgow coma scale, National Institute of Health Stroke Scale (NIHSS) and glucose on admission, and also diabetes mellitus and current nonsmoking were predictors of mortality. After multivariate analysis, ipsilateral ONSD (odds ratio [OR]: 6.24; 95% confidence interval [CI]: 1.18-33.01; p = 0.03) was an independent predictor of mortality, even after adjustment for other relevant prognostic factors. The best ipsilateral ONSD cutoff was 5.6mm (sensitivity 72% and specificity 83%) with an AUC of 0.71 (p = 0.02) for predicting mortality at 90 days.

CONCLUSION

Optic nerve ultrasound is a noninvasive, bedside, low-cost technique that can be used to identify increased ICP in acute supratentorial primary ICH patients. Among these patients, dilated ONSD is an independent predictor of mortality at 90 days.

Diagnostic Value of the Combination of Ultrasonographic Optic Nerve Sheath Diameter and Width of Crural Cistern with Respect to the Intracranial Pressure in Patients Treated with Decompressive Craniotomy

BACKGROUND

The monitoring of intracranial pressure (ICP) and detection of increased ICP are crucial because such increases may cause secondary brain injury and a poor prognosis. Although numerous ultrasound parameters, including optic nerve sheath diameter (ONSD), width of the crural cistern (WCC), and the flow velocities of the central retinal artery and middle cerebral artery, can be measured in patients after hemicraniectomy, researchers have yet to determine which of these is better for evaluating ICP. This study aimed to analyze the correlation between ICP and ultrasound parameters and investigate the best noninvasive estimator of ICP.

METHODS

This observational study enrolled 50 patients with brain injury after hemicraniectomy from January 2021 to December 2021. All patients underwent invasive ICP monitoring with microsensor, transcranial, and ocular ultrasound postoperatively. We measured the ONSD including the dura mater (ONSDI), the ONSD excluding the dura mater, the optic nerve diameter (OND), the eyeball transverse diameter (ETD), the WCC, and the flow velocities in the central retinal artery and middle cerebral artery. Then, we calculated the ONSDI-OND (the difference between ONSDI and OND) and ONSDI/ETD (the ratio of ONSDI to ETD). Patients were divided into a normal ICP group (n = 35) and an increased ICP group (≥ 20 mm Hg, n = 15) according to the ICP measurements. Correlations were then assessed between the values of the ultrasound parameters and ICP.

RESULTS

The ONSDI, ONSDI-OND, and ONSDI/ETD were positively associated with ICP (r = 0.455, 0.482, 0.423 and p = 0.001, < 0.001, 0.002, respectively), whereas the WCC was negatively associated with ICP (r = - 0.586, p < 0.001). The WCC showed the highest predictive power for increased ICP (area under the receiver operating characteristic curve [AUC] = 0.904), whereas the ONSDI-OND and ONSDI also presented with acceptable predictive power among the ONSD-related parameters (AUC = 0.831, 0.803, respectively). The cutoff values for increased ICP prediction for ONSDI, ONSDI-OND, and WCC were 6.29, 3.03, and 3.68 mm, respectively. The AUC of the combination of ONSDI-OND and WCC was 0.952 (95% confidence interval 0.896-1.0, p < 0.001).

CONCLUSIONS

The ONSDI, ONSDI-OND, and WCC were correlated with ICP and had acceptable accuracy levels in estimating ICP in patients after hemicraniectomy. Furthermore, WCC showed a higher diagnostic value than ONSD-related parameters, and the combination of ONSDI-OND and WCC was a satisfactory predictor of increased ICP.

Intracranial Pressure Monitoring and Management in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage is a medical condition that can lead to intracranial hypertension, negatively impacting patients' outcomes. This review article explores the underlying pathophysiology that causes increased intracranial pressure (ICP) during hospitalization. Hydrocephalus, brain swelling, and intracranial hematoma could produce an ICP rise. Although cerebrospinal fluid withdrawal via an external ventricular drain is commonly used, ICP monitoring is not always consistently practiced. Indications for ICP monitoring include neurological deterioration, hydrocephalus, brain swelling, intracranial masses, and the need for cerebrospinal fluid drainage. This review emphasizes the importance of ICP monitoring and presents findings from the Synapse-ICU study, which supports a correlation between ICP monitoring and treatment with better patient outcomes. The review also discusses various therapeutic strategies for managing increased ICP and identifies potential areas for future research.

Predictive factors for cerebrocardiac syndrome in patients with severe traumatic brain injury: a retrospective cohort study

Background and objective

Cerebrocardiac syndrome (CCS) is a severe complication of severe traumatic brain injury (sTBI) that carries high mortality and disability rates. Early identification of CCS poses a significant clinical challenge. The main objective of this study was to investigate potential risk factors associated with the development of secondary CCS in patients with sTBI. It was hypothesized that elevated right heart Tei index (TI), lower Glasgow Coma Scale (GCS) scores, and elevated cardiac troponin-I (cTnI) levels would independently contribute to the occurrence of CCS in sTBI patients.

Methods

A retrospective cohort study was conducted to identify risk factors for CCS secondary to sTBI. One hundred and fifty-five patients were enrolled with sTBI admitted to the hospital between January 2016 and December 2020 and divided them into a CCS group (n = 75) and a non-CCS group (n = 80) based on the presence of CCS. This study involved the analysis and comparison of clinical data from two patient groups, encompassing demographic characteristics, peripheral oxygen saturation (SPO2), neuron-specific enolase (NSE), cardiac troponin-I (cTnI), N-terminal pro-brain natriuretic peptide (NT-proBNP), optic nerve sheath diameter (ONSD), cardiac ultrasound, acute physiology and chronic health evaluation (APACHE II) scores, and GCS scores and so on. Multivariate logistic regression was employed to identify independent risk factors for CCS, and receiver operating characteristic (ROC) curves were used to assess their predictive value for CCS secondary to sTBI.

Results

The study revealed that 48.4% of sTBI patients developed secondary CCS. In the multivariate analysis model 1 that does not include NT-proBNP and cTnI, ONSD (OR = 2.582, 95% CI: 1.054-6.327, P = 0.038), right heart Tei index (OR = 2.81, 95% CI: 1.288-6.129, P = 0.009), and GCS (OR = 0.212, 95% CI: 0.086-0.521, P = 0.001) were independent risk factors for secondary CCS in sTBI patients. In multivariate analysis model 2 that includes NT-proBNP and cTnI, cTnI (OR = 27.711, 95%CI: 3.086-248.795, P = 0.003), right heart Tei index (OR = 2.736, 95% CI: 1.056-7.091, P = 0.038), and GCS (OR = 0.147, 95% CI: 0.045-0.481, P = 0.002) were independent risk factors for secondary CCS in sTBI patients. The area under the ROC curve for ONSD, Tei index, GCS, and cTnI were 0.596, 0.613, 0.635, and 0.881, respectively. ONSD exhibited a positive predictive value (PPV) of 0.704 and a negative predictive value (NPV) of 0.634. The Tei index demonstrated a PPV of 0.624 and an NPV of 0.726, while GCS had a PPV of 0.644 and an NPV of 0.815. On the other hand, cTnI exhibited a significantly higher PPV of 0.936 and an NPV of 0.817. These findings indicate that the Tei index, GCS score, and cTnI possess certain predictive value for secondary CCS in patients with sTBI.

Conclusions

The study provides valuable insights into the identification of independent risk factors for CCS secondary to sTBI. The findings highlight the significance of right heart Tei index, GCS score, and cTnI as potential predictive factors for CCS in sTBI patients. Further larger-scale studies are warranted to corroborate these findings and to provide robust evidence for the development of early intervention strategies aimed at reducing the incidence of CCS in this patient population.

Optic Nerve Ultrasound for Monitoring Deteriorating Intracranial Hemorrhage in a Patient on Extracorporeal Membrane Oxygenation: A Case Report

We present a 52-year-old male patient with cardiogenic shock who was placed on veno-arterial extracorporeal membrane oxygenation (ECMO) as a bridge to an orthotopic heart transplant. While on ECMO, the patient developed an acute intracranial bleed confirmed on computerized tomography (CT). However, his clinical status deteriorated and he was unstable for transport to evaluate for worsening hemorrhage. Instead, optic nerve sheath (ONS) ultrasonography was utilized to confirm increased intracranial pressure, which guided the goals of care until he stabilized enough to transport for advanced imaging. Repeat CT confirmed the worsening of his cerebellar bleed with obstructing hydrocephalus and brainstem compression. This case demonstrates how ONS ultrasound can be utilized in a cardiothoracic intensive care unit to evaluate sedated patients for new or worsening intracranial hemorrhage. In ECMO patients, who are often unstable with the risks of transportation for CT outweighing potential benefits, ONS ultrasonography can provide the care team with meaningful data on a patient's neurologic status.

Transcranial doppler in the non-invasive estimation of intracranial pressure in traumatic brain injury compared to other non-invasive methods in lower-middle income countries: Systematic review and meta-analysis

BACKGROUND

The prediction of raised Intracranial Pressure (ICP) with accuracy in Traumatic Brain Injury (TBI) patients is a clinically important decision and therapeutic tool. This study aimed to evaluate the existing methods used for non-invasive ICP monitoring in TBI patients in LMICs.

METHODS

Systematic searches of PubMed, Google Scholar, and ScienceDirect were performed from database inception to November 2021. Studies reporting the prediction of raised ICP in TBI patients by non-invasive means in LMICs were included. Pooled estimates of sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios with 95 %CI were calculated for each index test consisting of the fifteen studies, using the MEDDECIDE module 0.0.2 for meta-analysis of diagnostic test accuracy, reliability, and decision studies in JAMOVI 2.2.5.

RESULTS

A total of 1032 studies were identified, of which, 15 included 3316 patients with male predominance (n = 2458, 74.13%). Patients' ages range from 15 to 96 years with 40-80 (n = 1205, 36.34%), the most represented population. The ICP measured by Transcranial Doppler (TCD) had a sensitivity of 92.3%, and a specificity of 70%. The positive predictive value was 66.67%, with a negative predictive value of 93.33%. Furthermore, the positive Likelihood Ratio (+LR) was 3.69; 2<+LR < 5 and the negative Likelihood Ratio (-LR) 0.103; 0.1 < -LR < 0.2. We carried out a "Medical Decision", "Plots", "Fagan Normogram" and the ROC curve to find the perfect discrimination point of all the five tests used for the non-invasive measurement of ICP in the TBI patients in LMICs.

CONCLUSION

The TCD had shown high performance in its sensitivity and specificity, placing it on top of the other four different tests used in LMICs for the management of patients with TBI.

A prospective exploratory study to assess echocardiographic changes in patients with supratentorial tumors - Effect of craniotomy and tumor decompression

Background

Functional changes in the myocardium secondary to increased intracranial pressure (ICP) are studied sparingly. Direct echocardiographic changes in patients with supratentorial tumors have not been documented. The primary aim was to assess and compare the transthoracic echocardiography changes in patients with supratentorial tumors presenting with and without raised intracranial pressure for neurosurgery.

Methods

Patients were divided into two groups based on preoperative radiological and clinical evidence of midline shift of <6 mm without features of raised ICP (Group 1) or greater than 6mm with features of raised ICP (Group 2). Hemodynamic, echocardiographic, and optic nerve sheath diameter (ONSD) parameters were obtained during the preoperative period and 48 h after the surgery.

Results

Ninety patients were assessed, 88 were included for analysis. Two were excluded based on a poor echocardiographic window (1) and change in the operative plan (1). Demographic variables were comparable. About 27% of the patients in Group 2 had ejection fraction <55% and 21.2% had diastolic dysfunction in Group 2 in the preoperative period. There was a decrease in the number of patients with a left ventricular (LV) function <55% from 27% before surgery to 19% in the postoperative period in group 2. About 5.8% patients with moderate LV dysfunction in the preoperative period had normal LV function postoperatively. We found a positive correlation between ONSD parameters and radiological findings of raised intracranial pressure.

Conclusion

The study demonstrated that in patients with supratentorial tumors with ICP, cardiac dysfunction might be present in the preoperative period.

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.

Is Lumbar Puncture Needed? - Noninvasive Assessment of ICP Facilitates Decision Making in Patients with Suspected Idiopathic Intracranial Hypertension

PURPOSE

 Idiopathic intracranial hypertension (IIH) usually occurs in obese women of childbearing age. Typical symptoms are headache and sight impairment. Lumbar puncture (LP) is routinely used for both diagnosis and therapy (via cerebrospinal fluid drainage) of IIH. In this study, noninvasively assessed intracranial pressure (nICP) was compared to LP pressure (LPP) in order to clarify its feasibility for the diagnosis of IIH.

MATERIALS AND METHODS

 nICP was calculated using continuous signals of arterial blood pressure and cerebral blood flow velocity in the middle cerebral artery, a method which has been introduced recently. In 26 patients (f = 24, m = 2; age: 33 ± 11 years), nICP was assessed one hour prior to LPP. If LPP was > 20 cmH₂O, lumbar drainage was performed, LPP was measured again, and also nICP was reassessed.

RESULTS

 In total, LPP and nICP correlated with R = 0.85 (p < 0.001; N = 38). The mean difference of nICP-LPP was 0.45 ± 4.93 cmH₂O. The capability of nICP to diagnose increased LPP (LPP > 20 cmH₂O) was assessed by ROC analysis. The optimal cutoff for nICP was close to 20 cmH₂O with both a sensitivity and specificity of 0.92. Presuming 20 cmH₂O as a critical threshold for the indication of lumbar drainage, the clinical implications would coincide in both methods in 35 of 38 cases.

CONCLUSION

 The TCD-based nICP assessment seems to be suitable for a pre-diagnosis of increased LPP and might eliminated the need for painful lumbar puncture if low nICP is detected.

Translating Guidelines into Practical Practice: Point-of-Care Ultrasound for Pediatric Critical Care Clinicians

Point-of-care ultrasound (POCUS) is now transitioning from an emerging technology to a standard of care for critically ill children. POCUS can provide immediate answers to clinical questions impacting management and outcomes within this fragile population. Recently published international guidelines specific to POCUS use in neonatal and pediatric critical care populations now complement previous Society of Critical Care Medicine guidelines. The authors review consensus statements within guidelines, identify important limitations to statements, and provide considerations for the successful implementation of POCUS in the pediatric critical care setting.

A Case Report of Cerebral Hypoperfusion During Liver Transplant with a Focus on the Role of Intraoperative Neuromonitoring

Acute hepatic failure is characterized by rapid deterioration of hepatic function with encephalopathy in a patient without pre-existing liver disease. Bispectral index values had a significant correlation with cerebral perfusion. Transcranial Doppler can assess changes in cerebrovascular function and has the advantages of being noteworthy and widely available. This is a case report of a hepatic encephalopathy occurring during a deceased donor liver transplant in a patient presenting fulminant hepatitis. We briefly discuss some diagnostic methods highlighting the challenges of the anesthesiologist in managing this kind of patient in the context of a major surgery.

Does prolonged prone position affect intracranial pressure? prospective observational study employing Optic nerve sheath diameter measurements

BACKGROUND

Our aim in this observational prospective study is to determine whether the prone position has an effect on intracranial pressure, by performing ultrasound-guided ONSD (Optic Nerve Sheath Diameter) measurements in patients with acute respiratory distress syndrome (ARDS) ventilated in the prone position.

METHODS

Patients hospitalized in the intensive care unit with a diagnosis of ARDS who were placed in the prone position for 24 h during their treatment were included in the study. Standardized sedation and neuromuscular blockade were applied to all patients in the prone position. Mechanical ventilation settings were standardized. Demographic data and patients' pCO₂, pO₂, PaO₂/FiO₂, SpO₂, right and left ONSD data, and complications were recorded at certain times over 24 h.

RESULTS

The evaluation of 24-hour prone-position data of patients with ARDS showed no significant increase in ONSD. There was no significant difference in pCO₂ values either. PaO₂/FiO₂ and pO₂ values demonstrated significant cumulative increases at all times. Post-prone SPO2 values at the 8th hour and later were significantly higher when compared to baseline (p < 0.001).

CONCLUSION

As a result of this study, it appears that the prone position does not increase intracranial pressure during the first 24 h and can be safely utilized, given the administration of appropriate sedation, neuromuscular blockade, and mechanical ventilation strategy. ONSD measurements may increase the safety of monitoring in patients ventilated in the prone position.

Acil servise kafa travması ile başvuran hastaların yönetiminde optik sinir kılıf çapı ölçümünün değerlendirilmesi

Amaç: Literatürde ultrasonografik olarak optik sinir kılıf çapı ölçümünde saptanan değerler, kafa içi basınç artışı ile ilişkilendirilmektedir. Kafa içi basıncı ölçümü yapılan hastalar kritik alan ya da yoğun bakım hastalarıdır. Hafif ya da orta şiddette kafa travmasında patolojiyi ya da operasyona gidişi öngörmede ultrasonografi ile optik sinir kılıf çapı ölçümünün etkisi değerlendirilmemiştir. Çalışmamızda kafa travması ile başvuran hastaların, ultrasonografi ile optik sinir kılıf çapı ölçüm değerlerini, kraniyal tomografi bulguları ve hastaların klinik sonlanımları ile karşılaştırmayı hedefledik. Gereç ve Yöntem: Prospektif kesitsel planlanan çalışmada acil servise başvuran kafa travmalı hastalar hafif, orta ve şiddetli beyin hasarı olarak değerlendirildi. Çalışmaya dahil edilen hastaların ultrasonografi ile optik sinir kılıf çapları ölçüldü. Bulgular hastaların sonlanımları ve kraniyal tomografi özellikleri ile karşılaştırıldı. Bulgular: Acil servise kafa travması ile başvuran 58 hastanın incelemesinde en sık hafif şiddette travmatik beyin hasarına rastlandı. Hastaların %51,7 (30)’sinde yatış ya da operasyon ihtiyacı vardı. Optik sinir kılıf çapı ölçümlerinin ortalaması sağda 4,96±1,02 mm (3,1-7,3) solda ise 4,92±1,02 mm (3,3-7,8) olarak bulunmuştur. Optik sinir kılıf çapı ölçüm değerlerinin 5 mm ve üzerinde saptanması hastaneye yatışı öngörmede istatistiksel olarak anlamlı olarak saptandı (p

Non-Invasive Intracranial Pressure Monitoring

(1) Background: Intracranial pressure (ICP) monitoring plays a key role in the treatment of patients in intensive care units, as well as during long-term surgeries and interventions. The gold standard is invasive measurement and monitoring via ventricular drainage or a parenchymal probe. In recent decades, numerous methods for non-invasive measurement have been evaluated but none have become established in routine clinical practice. The aim of this study was to reflect on the current state of research and shed light on relevant techniques for future clinical application. (2) Methods: We performed a PubMed search for “non-invasive AND ICP AND (measurement OR monitoring)” and identified 306 results. On the basis of these search results, we conducted an in-depth source analysis to identify additional methods. Studies were analyzed for design, patient type (e.g., infants, adults, and shunt patients), statistical evaluation (correlation, accuracy, and reliability), number of included measurements, and statistical assessment of accuracy and reliability. (3) Results: MRI-ICP and two-depth Doppler showed the most potential (and were the most complex methods). Tympanic membrane temperature, diffuse correlation spectroscopy, natural resonance frequency, and retinal vein approaches were also promising. (4) Conclusions: To date, no convincing evidence supports the use of a particular method for non-invasive intracranial pressure measurement. However, many new approaches are under development.

Relation between partial arterial carbon dioxide pressure and pH value and optic nerve sheath diameter: a prospective self-controlled non-randomized trial study

OBJECTIVE

This study aims to determine if there is a correlation between differences in optic nerve sheath diameter (ONSD) and changes in PaCO2 and pH values that were measured in the arterial blood gas (ABG) before and after treatment in COPD patients with acute hypercarbic respiratory failure (AHRF).

MATERIALS AND METHODS

This study serves as a prospective self-controlled non-randomized trial study conducted in the emergency clinic of a tertiary hospital. Forty-four patients with COPD, who were found to have acidosis and hypercarbia in ABG and had an indication for non-invasive mechanic ventilation (NIMV), were analyzed prospectively. Demographic information, vital findings, initial ABG values, the ONSD measurement (before the NIMV treatment), consciousness state, and the ABG results obtained in the second hour of the monitoring and the ONSD measurement (after the NIMV treatment) were recorded.

RESULTS

In this study, 13 (29.5%) of the patients were female and 31 (70.5%) were male. The age distribution was evaluated as 68.3 ± 9.2 years; the minimum age was 54 and the maximum was 91. A high level of positively significant correlation was found between the mean ONSD and PaCO2 (p < 0.0001). There is a high fit (0.72) between the mean ONSD and PaCO2. A moderate level of negatively significant correlation was found between the mean ONSD and the pH (p < 0.0001). However, there is an insignificant low fit (0.32) between the mean ONSD and the pH.

CONCLUSION

The ONSD changed significantly and in a highly correlated manner to acute changes in PaCO2 levels.

Noninvasive intracranial pressure monitoring in central nervous system infections

Intracranial pressure (ICP) monitoring constitutes an important part of the management of traumatic brain injury. However, its application in other brain pathologies such as neuroinfections like acute bacterial meningitis is unclear. Despite focus on aggressive, prompt treatment, morbidity and mortality from acute bacterial meningitis remain high. Increased ICP is well-known to occur in severe neuroinfections. The increased ICP compromise cerebral perfusion pressure and may ultimately lead to brain stem herniation. Therefore, controlling the ICP could also be important in acute bacterial meningitis. However, risk factors for complications due to invasive monitoring among these patients may be significantly increased due to higher age and levels of comorbidity compared to the traumatic brain injury patient from which the ICP treatment algorithms are developed. This narrative review evaluates the different modalities of ICP monitoring with the aim to elucidate current status of non-invasive alternatives to invasive monitoring as a decision tool and eventually monitoring. Non-invasive screening using ultrasound of the optical nerve sheath, transcranial doppler, magnetic resonance imaging or preferably a combination of these modalities, provides measurements that can be used as a decision guidance for invasive ICP measurement. The available data do not support the replacement of invasive techniques for continuous ICP measurement in patients with increased ICP. Non-invasive modalities should be taken into consideration in patients with neuroinfections at low risk of increased ICP.