The relation of optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in pediatric neurosurgery practice - Part I: Correlations, age-dependency and cut-off values

Optic Nerve Sheath Diameter on Computed Tomography Scans Reflects Elevated Intracranial Pressure in Patients with Craniosynostosis

BACKGROUND

Assessment for elevated intracranial pressure (ICP) helps guide interventional decision-making to treat craniosynostosis. However, noninvasive techniques for measuring ICP are limited. This study assessed whether optic nerve sheath diameter (ONSD) on low-dose computed tomographic (CT) scans is associated with ICP in patients with craniosynostosis.

METHODS

Pediatric patients treated between 2014 and 2023 with craniosynostosis, intraoperative ICP measurements by direct subdural catheterization, and spectral domain-optical coherent tomographic (SD-OCT) data were included. ONSD was retrospectively assessed on preoperative CT scans by a masked neuroradiologist and compared with measures and proxies of ICP.

RESULTS

Among the 132 patients included (median age, 6.9 years; interquartile range, 4.7 to 9.5 years), 41 (31.1%) had a syndromic diagnosis. Maximal ONSD was increased in patients with an ICP of 15 mmHg or greater (6.1 mm versus 5.5 mm; P < 0.01) and 20 mmHg or greater (6.3 mm versus 5.6 mm; P < 0.01). Maximal ( r = 0.32; P < 0.001), minimum ( r = 0.26; P = 0.003), and average ( r = 0.29; P < 0.001) ONSD correlated with direct ICP measurements. ONSD and SD-OCT measurements were also correlated (maximum retinal nerve fiber layer, r = 0 .21, P = 0.04; maximum retinal thickness, r = 0.24, P = 0.02). An ONSD max threshold of 5.75 mm demonstrated 65% sensitivity and 64% specificity for detecting ICP of 15 mmHg or greater on optimized receiver operating characteristic curve analysis. Multivariable logistic regression generated an algorithm incorporating ONSD max and age to detect an ICP of 20 mmHg or greater with 64% sensitivity and 80% specificity.

CONCLUSIONS

ONSD measured on low-dose CT scans detected elevated ICP with moderate accuracy. Precision increased when patient age was taken into consideration. Given the ease of accessing CT scan data, this may be a helpful ICP proxy for clinical decision-making.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Diagnostic, II.

Evaluation of monitoring critical ill children with traumatic brain injury

Introduction

In traumatic brain injury (TBI), direct information can be obtained about cerebral blood flow, brain tissue oxygenation and cerebral perfusion pressure values. More importantly, an idea about the changes in these measurements can be obtained with multidimensional monitoring and widely used monitoring methods.

Aim of the study

We aimed to evaluate the monitoring of critically ill children who were followed up in our pediatric intensive care unit (PICU) due to TBI.

Material and Method

Twenty-eight patients with head trauma who were followed up in our tertiary PICU between 2018 and 2020 were included in the study. Cerebral tissue oxygenation, optic nerve sheath diameter (ONSD), Glasgow coma score (GCS) and Glasgow Outcome Score (GOSE) values were obtained from retrospective file records and examined.

Results

Male gender was 71.4% (n=20). When we classified TBI according to GCS, 50% (n=14) had moderate TBI and 50% had severe TBI. On the first day in the poor prognosis group, ONSD and nICP were found to be higher than in the good prognosis group (for ONSD, p=0.01; and for nICP, p=0.004). On the second day of hospitalization, the ONSD and nICP were significantly higher in the poor prognosis group than in the good prognosis group (for ONSD p=0.002; and for nICP p= 0.001). Cerebral tissue oxygenation values measured on the first and second days decreased significantly on the second day in both the good and poor prognosis groups (p=0.03, 0.006). In the good prognosis group, a statistically significant decrease was found in ONSD and nICP measurements taken on the 2nd day compared to the measurements taken at the time of hospitalization (for ONSD p=0.004; for nICP p<0.001).

Conclusion

The aim of multidimensional follow-up in traumatic brain injury is to protect the brain from both primary and secondary damage; for this reason, it should be followed closely with multimonitoring methods that are possibly multidisciplinary.

Evaluation of optic nerve sheath diameter measurements in postictal pediatric patients

INTRODUCTION

Prolonged seizures cause cytotoxic edema and increase intracranial pressure. Optic nerve sheath diameter (ONSD) and its ratio to eyeball transverse diameter (ONSD/ETD) offer a noninvasive method for monitoring intracranial pressure changes. We calculated the ONSD and ONSD/ETD ratio of postictal children using computed tomography and evaluated the relationship between those values and seizure duration.

METHODS

The ONSD and ONSD/ETD ratios were calculated using non-contrast computed head tomography for 88 postictal children with generalized and focal seizures and 109 healthy controls. ONSD was measured as the thickness at 3 mm from the optic disc and the ETD was measured as the widest diameter of the eyeball from retina to retina. The ONSD/ETD ratio was obtained by averaging the left and right ONSD values and dividing that value by the mean of the left and right ETD values.

RESULTS

Fifty-eight (63.6%) of the children had focal seizures, and 64% of the seizures of 59 children (67%) were classified as prolonged seizures. The median ONSD and ONSD/ETD ratio were significantly higher in postictal children compared to healthy controls (p < 0.001 and p < 0.001, respectively). In postictal children presenting with generalized seizures, nonsignificant differences in the median ONSD and ONSD/ETD ratio were observed (p = 0.43 and p < 0.87, respectively). Children with prolonged seizures had significantly different ONSD values (p = 0.015) but the ONSD/ETD ratio did not differ significantly (p = 0.87). The analysis of postictal children indicated a significant correlation between seizure duration and ONSD (r = 0.257, p = 0.016), but not the ONSD/ETD ratio (r = 0.065, p = 0.545). ONSD values of (> 4.84 mm) were most effective in distinguishing patients with prolonged seizures compared to those without, with sensitivity and specificity of 65.6% and 72.5%.

CONCLUSION

ONSD and ONSD/ETD values are potentially useful in the evaluation of postictal children, but they do not exhibit adequate discriminative accuracy by themselves. The significance of these parameters in observing seizure duration in postictal children may be a critical area of interest for future investigations.

The Current State of Non-Invasive Measurement of Intracranial Pressure in Patients with Craniosynostosis: A Systematic Review

Introduction:

Despite being invasive, direct measurements remain the gold standard to measure intra-cranial pressure (ICP) in patients with craniosynostosis. However, there has been persistent effort to develop non-invasive modalities to measure ICP, possibly avoiding some of the risks of direct measurements. Here, we conduct a systematic review of the evidence behind various non-invasive modalities to monitor ICP in patients with craniosynostosis.

Methods:

A systematic review was conducted using PubMed, Cochrane, and Web of Science databases to identify studies describing the use of non-invasive ICP measurements in patients with craniosynostosis. Studies were included if they assessed a non-invasive method of ICP monitoring against a direct/invasive ICP monitoring technique in patients with craniosynostosis. Non-English and non-human studies were excluded.

Results:

A total of 735 studies were screened, of which 52 were included in the study. Nine methods of non-invasive ICP measurement were identified, with varying sensitivities and specificities in detecting elevated ICP. Specifically, optical coherence tomography (OCT), and ocular ultrasonography demonstrated ability to accurately measure ICP when compared to direct measurements.

Conclusion:

Here, we present the first systemic-review of the current literature surrounding non-invasive modalities to measure ICP in patients with craniosynostosis. While direct measurement remains the gold-standard, multiple reviewed modalities have shown promise in accurately measuring ICP. Of these, OCT has the most rigorous evidence supporting its use. Ocular sonography has also shown promise, albeit without as robust evidence supporting its use. Regardless, further investigation is required before any modality is able to obviate the need for invasive, direct measurements.

Optic nerve sheath diameter as a non-invasive tool to detect clinically relevant raised intracranial pressure in children: an observational analytical study

BACKGROUND

Raised intracranial pressure (ICP) contributes to approximately 20% of the admissions in the paediatric intensive care unit (PICU) in our setting. Timely identification and treatment of raised ICP is important to prevent brain herniation and death in such cases. The objective of this study was to examine the role of optic nerve sheath diameter (ONSD) in detecting clinically relevant raised ICP in children.

METHODS

A hospital-based observational analytical study in a PICU of a tertiary care institute in India on children aged 2-14 years. ONSD was measured in all children on three time points that is, day 1, day 2 and between day 4 and 7 of admission. ONSD values were compared between children with and without clinical signs of raised ICP.

RESULTS

Out of 137 paediatric patients recruited, 34 had signs of raised ICP. Mean ONSD on day 1 was higher in children with signs of raised ICP (4.99±0.57 vs 4.06±0.40; p<0.01). Mean ONSD on day 2 also was higher in raised ICP patients (4.94±0.55 vs 4.04±0.40; p<0.01). The third reading between days 4 and 7 of admission was less than the first 2 values but still higher in raised ICP patients (4.48±1.26 vs 3.99±0.57; p<0.001). The cut-off ONSD value for detecting raised ICP was 4.46 mm on the ROC curve with an area under curve 0.906 (95% CI 0.844 to 0.968), 85.3% sensitivity and 86.4% specificity. There was no difference in ONSD between the right and the left eyes at any time point irrespective of signs of raised ICP.

CONCLUSION

We found that measurement of ONSD by transorbital ultrasound was able to detect clinically relevant raised ICP with an excellent discriminatory performance at the cut-off value of 4.46 mm.

Optic nerve sheath diameter correlates with both success and failure of hydrocephalus treatment in pediatric patients with pineal region lesions

BACKGROUND

Pineal region lesions in children are heterogenous pathologies often symptomatic due to occlusive hydrocephalus and thus elevated intracranial pressure (ICP). MRI-derived parameters to assess hydrocephalus are the optic nerve sheath diameter (ONSD) as a surrogate for ICP and the frontal occipital horn ratio (FOHR), representing ventricle volume. As elevated ICP may not always be associated with clinical signs, the adjunct of ONSD could help decision making in patients undergoing treatment. The goal of this study is to assess the available magnetic resonance imaging (MRI) of patients with pineal region lesions undergoing surgical treatment with respect to pre- and postoperative ONSD and FOHR as an indicator for hydrocephalus.

METHODS

Retrospective data analysis was performed in all patients operated for pineal region lesions at a tertiary care center between 2010 and 2023. Only patients with pre- and postoperative MRI were selected for inclusion. Clinical data and ONSD at multiple time points, as well as FOHR were analyzed. Imaging parameter changes were correlated with clinical signs of hydrocephalus before and after surgical treatment.

RESULTS

Thirty-three patients with forty operative cases met the inclusion criteria. Age at diagnosis was 10.9 ± 4.6 years (1-17 years). Hydrocephalus was seen in 80% of operative cases preoperatively (n = 32/40). Presence of hydrocephalus was associated with significantly elevated preoperative ONSD (p = 0.006). There was a significant decrease in ONSD immediately (p < 0.001) and at 3 months (p < 0.001) postoperatively. FOHR showed a slightly less pronounced decrease (immediately p = 0.006, 3 months p = 0.003). In patients without hydrocephalus, no significant changes in ONSD were observed (p = 0.369). In 6/6 patients with clinical hydrocephalus treatment failure, ONSD increased, but in 3/6 ONSD was the only discernible MRI change with unchanged FOHR.

CONCLUSIONS

ONSD measurements may have utility in evaluating intracranial hypertension due to hydrocephalus in patients with pineal region tumors. ONSD changes appear to have value in assessing hydrocephalus treatment failure.

Ultrasound-guided initial diagnosis and follow-up of pediatric idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension in children often presents with non-specific symptoms found in conditions such as hydrocephalus. For definite diagnosis, invasive intracranial pressure measurement is usually required. Ultrasound (US) of the optic nerve sheath diameter provides a non-invasive method to assess intracranial pressure. Transtemporal US allows imaging of the third ventricle and thus assessment for hydrocephalus.

OBJECTIVE

To investigate whether the combination of US optic nerve sheath and third ventricle diameter can be used as a screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure and exclude hydrocephalus as an underlying pathology. Further, to analyze whether both parameters can be used to monitor treatment outcome.

MATERIALS AND METHODS

We prospectively included 36 children with idiopathic intracranial hypertension and 32 controls. Using a 12-Mhz linear transducer and a 1-4-Mhz phased-array transducer, respectively, optic nerve sheath and third ventricle diameters were determined initially and during the course of treatment.

RESULTS

In patients, the mean optic nerve sheath diameter was significantly larger (6.45±0.65 mm, controls: 4.96±0.32 mm) and the mean third ventricle diameter (1.69±0.65 mm, controls: 2.99±1.31 mm) was significantly smaller compared to the control group, P<0.001. Optimal cut-off values were 5.55 mm for the optic nerve sheath and 1.83 mm for the third ventricle diameter.

CONCLUSIONS

The combined use of US optic nerve sheath and third ventricle diameter is an ideal non-invasive screening tool in pediatric idiopathic intracranial hypertension to indicate elevated intracranial pressure while ruling out hydrocephalus. Treatment can effectively be monitored by repeated US, which also reliably indicates relapse.

Transorbital point-of-care ultrasound versus fundoscopic papilledema to support treatment indication for potentially elevated intracranial pressure in children

PURPOSE

To compare transorbital point-of-care ultrasound techniques -optic nerve sheath diameter (US-ONSD) and optic disc elevation (US-ODE)- with fundoscopic papilledema to detect potentially raised intracranial pressure (ICP) with treatment indication in children.

METHODS

In a prospective study, 72 symptomatic children were included, 50 with later proven disease associated with raised ICP (e.g. pseudotumour cerebri, brain tumour, hydrocephalus) and 22 with pathology excluded. Bilateral US-ONSD and US-ODE were quantified by US using a 12-MHz-linear-array transducer. This was compared to fundoscopic optic disc findings (existence of papilledema) and, in 28 cases, invasively measured ICP values.

RESULTS

The sensitivity and specificity of a cut-off value of US-ONSD (5.73 mm) to detect treatment indication for diseases associated with increased ICP was 92% and 86.4%, respectively, compared to US-ODE (0.43 mm) with sensitivity: 72%, specificity: 77.3%. Fundoscopic papilledema had a sensitivity of 46% and a specificity of 100% in this context. Repeatability and observer-reliability of US-ODE examination was eminent (Cronbach's α = 0.978-0.989). Papilledema was detected fundoscopically only when US-ODE was > 0.67 mm; a US-ODE > 0.43 mm had a positive predictive value of 90% for potentially increased ICP.

CONCLUSION

In our cohort, transorbital point-of-care US-ONSD and US-ODE detected potentially elevated ICP requiring treatment in children more reliably than fundoscopy. US-ONSD and US-ODE indicated the decrease in ICP after treatment earlier and more reliably than fundoscopy. The established cut-off values for US-ONSD and US-ODE and a newly developed US-based grading of ODE can be used as an ideal first-line screening tool to detect or exclude conditions with potentially elevated ICP in children.

Optic nerve sheath diameter and its association with brain swelling in pediatric cerebral malaria: a retrospective study

Introduction

Mortality in pediatric cerebral malaria (CM) in low- and middle-income countries (LMICs) is associated with brain swelling on magnetic resonance imaging (MRI); however, MRI is unavailable in most LMICs. Optic nerve sheath diameter (ONSD) measurement is an inexpensive method of detecting increased intracranial pressure compared with the invasive opening pressure (OP). Our primary objective was to determine if increased ONSD correlated with brain swelling on MRI in pediatric CM. Our secondary objective was to determine if increased ONSD correlated with increased OP and/or poor neurological outcome in pediatric CM. We hypothesized that increased ONSD would correlate with brain swelling on MRI and increased OP and that ONSD would be higher in survivors with sequelae and non-survivors.

Methods

We performed a retrospective chart review of children aged 0-12 years in Blantyre, Malawi, from 2013 to 2022 with CM as defined by the World Health Organization. Brain swelling on admission MRI was characterized by brain volume scores (BVS); severe swelling was scored as 7-8, mild-to-moderate as 4-6, normal as 3. The admission ONSD was measured via ultrasound; it was defined as abnormal if it was >4.5 mm in children >1 year and >4 mm in children <1 year. Favorable outcome was defined as a normal neurological exam on discharge in survivors. The primary and secondary objectives were evaluated using Spearman's correlation; and the demographics were compared using chi-square and the Kruskal-Wallis test (Stata, College Station, TX, USA).

Results

Median age of the 207-patients cohort was 50 months [interquartile range (IQR) 35-75]; 49% (n = 102) were female. Of those, 73% (n = 152) had a favorable outcome, and 14% (n = 30) died. Twenty-nine (14%) had a normal BVS, 134 (65%) had mild-to-moderate swelling, and 44 (21%) had severe swelling. ONSD was elevated in 86% (n = 178) of patients, while 12% of patients had increased OP. There was a weakly positive correlation between BVS and ONSD (r = 0.14, p = 0.05). The median ONSD was not significantly different compared by discharge outcome (p = 0.11) or by BVS (p = 0.18).

Conclusion

ONSD was not a reliable tool to correlate with BVS, neurological outcome, or OP in children with CM. Future studies to identify alternative methods of early identification of CM patients at highest risk for morbidity and mortality are urgently needed.

Non-Invasive Quantitative Approximation of Intracranial Pressure in Pediatric Idiopathic Intracranial Hypertension Based on Point-of-Care Ultrasound of the Optic Nerve Sheath Diameter

BACKGROUND

To investigate whether ultrasound-based optic nerve sheath diameter (US-ONSD) is a reliable measure to follow up children with idiopathic intracranial hypertension (IIH). In addition, to analyze the inter- and intra-individual relationships between US-ONSD and intracranial pressure (ICP), and to investigate whether an individualized mathematical regression equation obtained from two paired US-ONSD/ICP values can be used to approximate ICP from US-ONSD values.

METHODS

159 US examinations and 53 invasive ICP measures via lumbar puncture (LP) were performed in 28 children with IIH. US-ONSD was measured using a 12 Mhz linear transducer and compared to ICP values. In 15 children, a minimum of 2 paired US-ONSD/ICP determinations were performed, and repeated-measures correlation (rmcorr) and intra-individual correlations were analyzed.

RESULTS

The cohort correlation between US-ONSD and ICP was moderate (r = 0.504, p < 0.01). Rmcorr (r = 0.91, p < 0.01) and intra-individual correlations (r = 0.956-1) of US-ONSD and ICP were excellent. A mathematical regression equation can be calculated from two paired US-ONSD/ICP values and applied to the individual patient to approximate ICP from US-ONSD.

CONCLUSIONS

Related to excellent intra-individual correlations between US-ONSD and ICP, an individualized regression formula, created from two pairs of US-ONSD/ICP values, may be used to directly approximate ICP based on US-ONSD values. Hence, US-ONSD may become a non-invasive and reliable measure to control treatment efficacy in pediatric IIH.

Influence of sex and disease etiology on the development of papilledema and optic nerve sheath extension in the setting of intracranial pressure elevation in children

Introduction

Dilatation of the optic nerve sheath diameter and swelling of the optic disc are known phenomena associated with intracranial pressure elevation.

Research question

Do sex and disease etiology have an impact on the development of optic disc elevation and optic nerve sheath extension in children in the setting of ICP elevation? Fundoscopic papilledema and point-of-care-ultrasound techniques-optic nerve sheath diameter (US-ONSD) and optic disc elevation (US-ODE) - were compared in this regard.

Material and methods

72 children were included in this prospective study; 50 with proven pathology (e.g. pseudotumor cerebri, tumor), 22 with pathology excluded. Bilateral US-ONSD and US-ODE were quantified by US using a 12-MHz-linear-array-transducer. This was compared with fundoscopic optic disc findings and in 28 patients with invasive ICP values, stratified for sex and etiology.

Results

In patients with proven disease, significant more girls (69%) had fundoscopic papilledema compared with boys (37%, p < 0.05). Girls had also larger US-ODE values (0.86 ± 0.36 mm vs. 0.65 ± 0.40 mm in boys). 80% of tumor patients had initial papilledema (100% girls, 79% boys), compared with 50% in pseudotumor cerebri (PTC) (83% girls, 30% boys). US-ONSD had no sex- and no etiology-specificity.

Discussion and conclusion

Presence of papilledema appears to be influenced by sex and etiology, whereas US-ONSD is not. Girls seem more likely to develop papilledema under similar conditions. Male sex and PTC appear as risk factors for being undetected by fundoscopic findings. US-ONSD and US-ODE seem useful tools to identify pathologies with potentially increased ICP requiring treatment in children regardless of sex and etiology.

Variability of the optic nerve sheath diameter on brain computed tomography in Turkish children based on sex and age

BACKGROUND

Optic nerve sheath diameter (ONSD) measurement is a noninvasive method that can be used for intracranial pressure monitoring. Several studies have investigated normal ONSD values in children, but no general consensus has been reached yet.

OBJECTIVES

The aim of our study was to reveal normal ONSD, eyeball transverse diameter (ETD), and ONSD/ETD values on brain computed tomography (CT) in healthy children aged 1 month to 18 years.

METHODS

Children admitted to the emergency department with minor head trauma and had normal brain CT were included in the study. The demographic characteristics of the patients (age and sex) were recorded, and the patients were divided into four age groups: 1 month to 2 years, 2 to 4 years, 4 to 10 years, and 10 to 18 years.

RESULTS

The images of 332 patients were analyzed. When the median values of all measurement parameters (right and left ONSD, ETD, and ONSD/ETD) were compared between the right and left eyes, no statistically significant differences were found. When the same parameters were compared according to age group, the ONSD and ETD values differed significantly (values of males were found to be higher), but the ONSD proximal/ETD and ONSD middle/ETD values did not differ significantly.

CONCLUSION

In our study, normal ONSD, ETD, and ONSD/ETD values were determined according to age and sex in healthy children. As the ONSD/ETD index did not statistically significantly differ according to age and sex, diagnostic studies for traumatic brain injuries can be performed using the index.

Venous 3D Phase Contrast Magnetic Resonance Angiography Increases Diagnostic Certainty in Children with Ventriculoperitoneal Shunt and Suspected Shunt Failure

BACKGROUND

Clinical symptoms in children with suspected malfunction of ventriculoperitoneal shunt may not be specific and difficult to interpret. The presence or absence of ventricular enlargement on magnetic resonance imaging (MRI) does not reliably predict raised intracranial pressure (ICP) in these patients. Therefore, the aim was to investigate the diagnostic utility of 3D venous phase-contrast MR angiography (vPCA) in these patients.

MATERIALS

The MR studies of two groups of patients at two different examination dates were retrospectively analyzed; one group without clinical symptoms on both examinations and one with symptoms of shunt dysfunction on one examination receiving surgery. Both MRI examinations had to have been performed including axial T2 weighted (T2-w) images and 3D vPCA. Two (neuro)radiologists evaluated T2-w images alone and in combination with 3D vPCA in terms of suspected elevated ICP. Interrater reliability, sensitivity and specificity were assessed.

RESULTS

Compression of venous sinuses was seen significantly more often in patients with shunt failure (p = 0.00003). Consequently, evaluation of 3D vPCA and T2-w images increases sensitivity to 0.92/1.0 compared to T2-w images alone with 0.69/0.77, the interrater agreement for the diagnosis of shunt failure rises from κ = 0.71 to κ = 0.837. Concerning imaging markers, three groups could be identified in children with shunt failure.

CONCLUSION

In accordance with the literature, the results show that ventricular morphology alone is an unreliable marker for elevated ICP in children with shunt malfunction. The findings confirmed 3D vPCA as a valuable supplemental diagnostic tool improving diagnostic certainty for children with unchanged ventricular size in cases of shunt failure.

Retrospective longitudinal assessment of optic nerve sheath diameter in patients with malignant glioma

INTRODUCTION

Glioblastoma (GBM) is a tumor with rapid growth and a possible relationship to elevated intracranial pressure (ICP). High ICP may not always be associated with clinical signs. A non-invasive technique for assessment of ICP is measuring the optic nerve sheath diameter (ONSD). Identifying patients who need immediate intervention is of importance in neuro-oncological care. The goal of this study is to assess the available magnetic resonance imaging (MRI) of patients with GBM with respect to pre- and postoperative ONSD.

METHODS AND MATERIALS

Retrospective data analysis was performed on all patients operated for GBM at a tertiary care center between 2010 and 2020. Two pre and one postoperative MRI had to be available. Clinical data and ONSD at multiple time points were analyzed and correlated, as well as preoperative volumetrics.

RESULTS

Sixty-seven patients met the inclusion criteria. Clinical signs of elevated ICP were seen in 25.4% (n = 17), while significant perifocal edema was present in 67.2% (n = 45) of patients. Clinical signs of preoperatively elevated ICP were associated with significantly elevated ONSD at diagnosis (p < 0.001) as well as preoperative tumor volume (p < 0.001). Significant perifocal edema at the time of diagnosis was associated with elevated ONSD (p = 0.029) and higher tumor volume (p = 0.003). In patients with significant edema, ONSD increased significantly between preoperative MRIs (p = 0.003/005). In patients with clinical signs of raised ICP, ONSD also increased, whereas it was stable in asymptomatic patients (yes: 5.01+/-4.17 to 5.83+/-0.55 mm, p = 0.010, no: 5.17+/-0.46 mm to 5.38+/-0.41 mm, p = 0.81). A significant increase of ONSD from diagnosis to preoperative MRI and a significant decrease until 3 months postoperatively were observed (p < 0.001).

CONCLUSIONS

ONSD might help identify high ICP in patients with GBM. In this first-of-its kind study, we observed a significant increase of ONSD preoperatively, likely associated with edema. Postoperatively, ONSD decreased significantly until 3 months after surgery and increased again at 12 months. Further prospective data collection is warranted.

Effect of paediatric caudal injection volume on optic nerve sheath diameter and regional cerebral oximetry: A randomised trial

BACKGROUND

Caudal injections commonly used for neuraxial anaesthesia in children can displace cerebrospinal fluid cranially causing safety concerns in terms of raised intracranial pressure. Optic nerve sheath diameter (ONSD) is a noninvasive surrogate for the measurement of intracranial pressure. Regional cerebral oximetry (CrSO 2 ) can monitor brain oxygenation, which may decrease by a reduction in cerebral flow due to increased intracranial pressure.

OBJECTIVES

Comparing how caudal injection volumes of 0.8 and 1.25 ml kg -1 influence ONSD and CrSO 2 within the first 30 min after injection.

DESIGN

Prospective, randomised and parallel group trial.

SETTING

Operating room.

PATIENTS

Fifty-eight elective paediatric surgical patients between ages 1 and 7 years old, ASA class I or II, without previous intracranial or ocular pathology and surgery appropriate for single - shot caudal anaesthesia.

INTERVENTION

Single-shot caudal anaesthesia with 0.8 ml kg -1 (group L, n  = 29) and 1.25 ml kg -1 (group H, n  = 29) of 2 mg kg -1 bupivacaine solution.

MAIN OUTCOME MEASURES

Optic nerve sheath diameter measured with ultrasonography and regional cerebral oximetry measured by near - infrared spectroscopy before (NIRS), immediately after, 10, 20 and 30 min after the block.

RESULTS

Mean ONSD values increased from a baseline of 4.4 ± 0.2 mm to a maximum of 4.5 ± 0.2 mm 20 min after injection in group L and from a baseline of 4.5 ± 0.3 mm to a maximum of 4.8 ± 0.3 mm 10 min after injection in group H. Eight of 29 patients in group H and none in group L had an ONSD increase by more than 10%. Both groups had a reduction of less than 2.5% in CrSO 2 .

CONCLUSION

Caudal injection with 1.25 ml kg -1 increased ONSD, an indirect measurement of ICP, more than 0.8 ml kg -1 and neither volume caused a clinically important reduction in CrSO 2 .

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04491032.

Multimodal Neuromonitoring in Pediatric Neurocritical Care: Current Perspectives

Children with neurological illness in the critical care unit are always at higher risk of developing secondary brain injury (SBI). Brain insult can lead to changes in cerebral autoregulation, intracranial pressure (ICP), cerebral oxygenation, and metabolism. This can cause a raised ICP, cerebral ischemia, hypoxia, excitotoxicity, cellular energy failure, and nonconvulsive status epilepticus. Simultaneous and continuous assessment of these parameters will help to improve patient care and neurological outcomes. Even though clinical examination and neuroimaging can help in the initial diagnosis of the neurological illness, they may not be helpful in continuous monitoring of cerebral pathophysiological changes. The ideal single neuromonitoring device to detect these real-time changes is currently unavailable. However, a range of invasive and noninvasive monitors are available to monitor these cerebral functional parameters. Invasive monitoring techniques include invasive ICP monitoring, cerebral autoregulation monitoring, brain tissue partial oxygen pressure, and cerebral microdialysis. Noninvasive-monitoring techniques include pupillometry, brain and ocular ultrasonography, near-infrared spectroscopy, and electrophysiological monitoring. Multimodal (MM) neuromonitoring involves incorporating these techniques and tools for the early identification and treatment of primary and secondary brain insults. The utility and feasibility of most of these techniques are well described in adult neurocritical care. Even though the evidence on their usage in children is primarily available in pediatric traumatic brain injury, the emerging data help to further expand their utility in pediatric nontraumatic coma. MM neuromonitoring aims to provide clinical and pathophysiological information to the intensivists to improve their understanding of the child's neurological status and to formulate patient-specific treatment approaches.

Diagnostic role of optic nerve sheath diameter and brain blood flow in neonates with hypoxic-ischemic encephalopathy

PURPOSE

The primary aim was to study the optic nerve sheath diameter (ONSD) measurements and cerebral blood flows in neonates with hypoxic-ischemic encephalopathy (HIE) who were at risk of cerebral edema and to compare the measurements with healthy neonates.

METHODS

Neonates diagnosed as Stage II and III HIE patients were enrolled in the study group. ONSD measurements and blood flow Doppler studies in the first 24-48 h of life during hypothermia and following hypothermia treatment. Magnetic resonance imaging (MRI) and transfontanelle ultrasonography were performed within the first 4-7 days of life in all HIE patients. Saved US and MRI images were assessed by a blind pediatric radiologist later on.

RESULTS

Data from a total of 63 infants (42 in the HIE group and 21 in the control group) were analyzed. Both the right and left ONSD measurements were comparable between HIE and control groups. However, both resistive index (RI) and pulsatility index (PI) of the middle cerebral artery were found to be significantly lower in HIE (0.69 ± 0.09 and 1.14 (0.98-1.30)) group when compared with controls (0.75 ± 0.04 and 1.41 (1.25-1.52)) (p < 0.01). Ultrasonographic ONSD measurements were significant and strongly correlated with MRI ONSD measurements for both sides (r = 0.91 and r = 0.93, p < 0.01). Doppler studies during normothermia were comparable with the control group and significantly increased following therapeutic hypothermia.

CONCLUSION

Ultrasonographic ONSD measurements can be reliably performed in term neonates with high compatibility to MRI. No significant effect on ONSD measurements was found related to asphyxia and therapeutic hypothermia despite the significant alteration observed in Doppler studies.

The ASPECT Hydrocephalus System: a non-hierarchical descriptive system for clinical use

In patients with hydrocephalus, prognosis and intervention are based on multiple factors. This includes, but is not limited to, time of onset, patient age, treatment history, and obstruction of cerebrospinal fluid flow. Consequently, several distinct hydrocephalus classification systems exist. The International Classification of Diseases (ICD) is universally applied, but in ICD-10 and the upcoming ICD-11, hydrocephalus diagnoses incorporate only a few factors, and the hydrocephalus diagnoses of the ICD systems are based on different clinical measures. As a consequence, multiple diagnoses can be applied to individual cases. Therefore, similar patients may be described with different diagnoses, while clinically different patients may be diagnosed identically. This causes unnecessary dispersion in hydrocephalus diagnostics, rendering the ICD classification of little use for research and clinical decision-making. This paper critically reviews the ICD systems for scientific and functional limitations in the classification of hydrocephalus and presents a new descriptive system. We propose describing hydrocephalus by a system consisting of six clinical key factors of hydrocephalus: A (anatomy); S (symptomatology); P (previous interventions); E (etiology); C (complications); T (time-onset and current age). The "ASPECT Hydrocephalus System" is a systematic, nuanced, and applicable description of patients with hydrocephalus, with a potential to resolve the major issues of previous classifications, thus providing new opportunities for standardized treatment and research.

Optic Nerve Ultrasound Evaluation in Children: A Review

Managing patients with neurocritical illness requires monitoring and treating elevated intracranial pressure (ICP), especially in cases in children. In terms of precise and real-time measurements, invasive ICP measurements are presently the gold standard for the initial diagnosis and follow-up ICP assessments. As a rapid and non-invasive way to detect elevated ICP, point-of-care ultrasonography (POCUS) of optic nerve sheath diameter (ONSD) has been proposed. The utility of bedside POCUS of ONSD to detect elevated ICP with excellent diagnostic test accuracy in adults has already been demonstrated. Nonetheless, data on the relationship between POCUS of ONSD and ICP in children are scarce. Therefore, the purpose of this review is to point out the most recent findings from the pediatric published literature and briefly discuss what was assessed with ONSD ultrasound examination, and also to describe and discuss the diagnostic procedures available for optic nerve ultrasound appraisal. A search of the medical databases PubMed and Scopus was carried out. The terms such as "ocular ultrasonography", "ICP assessment", "children", "point-of-care ultrasound", and "POCUS" were searched. In conclusion, the use of the standardized A-scan technique coupled with the B-scan technique should be suggested to provide data that are as accurate, precise, repeatable, and objective as possible.

Role of Orbital Ultrasound in the Monitoring of Children with Raised Intracranial Pressure—Prospective Observational Study Conducted in Tertiary Care Centre

Our objective was to evaluate the role of optic nerve sheath diameter measurement by orbital ultrasound in monitoring children with nontraumatic coma and increased intracranial pressure (ICP). A single-center prospective observational study was conducted in the pediatric intensive care unit (PICU) of a tertiary care teaching hospital in Puducherry, India. Children admitted to the PICU with features of raised ICP were enrolled. Baseline characteristics and raised ICP characteristics were recorded. Optic nerve sheath diameter (ONSD) measurements were taken in all children in the supine position using bedside ultrasound with a 12 MHz linear probe. The probe was initially placed in the axial plane, and measurements were taken at a distance of 3 mm posterior to the site at which the optic nerve enters the globe. Measurements were recorded sequentially 8th hourly till ICP features got resolved or the patient died. Along with each measurement, clinical parameters were recorded. The ONSD measurements were compared with clinical features. We also recruited children admitted to the PICU for other conditions without features of raised ICP as controls. We compared ONSD measurements of cases with controls. In total, 185 children were recruited, of which 81 had features of raised ICP and 104 were without increased ICP. The ONSD measurements in children with raised ICP were significantly higher as compared with those without ICP. Among children with raised ICP, there was a negative correlation between ONSD and Glasgow Coma Scale scores (r = −0.739, p ≤ 0.0001). In children with raised ICP, there was a significant difference in ONSD at different intervals, demonstrating a falling trend from admission to 32nd-hour readings. ONSD measurements were higher in children with clinical signs of increased ICP compared with controls, thereby suggesting that this noninvasive measure may be helpful in the neuromonitoring of children with neurologic insults.

Comparison of Midazolam and Propofol Infusion to Suppress Stress Response in Patients With Severe TBII: A Prospective, Randomized Controlled Trial

Objective

The stress response following traumatic brain injury (TBI) is a preventable cause of secondary brain injury. This can be prevented using sedation in the intensive care unit (ICU). To date, the choice of sedative agent for preventing stress response is not well-studied in literature.

Methods

This prospective randomized controlled trial included 60 patients with severe TBI admitted to ICU. The patients were randomized into 2 study groups according to the choice of sedation: propofol (group I) and midazolam infusion (group II). The serum cortisol was measured as the primary outcome at admission to ICU and 48 hours following sedation infusion. The baseline Glasgow coma scale, hemodynamic, optic nerve sheath diameter (ONSD), and computed tomography scan findings were noted at admission. Glasgow outcome scale (GOS) was measured as a neurological outcome at discharge from ICU.

Results

There was a statistically significant reduction in serum cortisol level in both the study groups (Δ cortisol, p-value=134.91 (50.5,208.2), 0.00 and 118.8 (42.6,160.4), 0.00, in group I and II, respectively). Serum cortisol levels were comparable among both groups at baseline and 48 hours. Similarly, there was a statistically significant difference in ONSD in both groups, but there was no difference in ONSD value between the groups at 48 hours. The GOS was also similar in both groups at discharge from ICU.

Conclusion

The study demonstrated a similar reduction in serum cortisol levels following 48 hours of propofol or midazolam infusion in patients with severe TBI.

Hydrocephalus Study Design: Testing New Hypotheses in Clinical Studies and Bench-to-Bedside Research

In this article, we aimed to describe some of the currently most challenging problems in neurosurgical management of hydrocephalus and how these can be reasons for inspiration for and development of research. We chose 4 areas of focus: 2 dedicated to improvement of current treatments (shunt implant surgery and endoscopic hydrocephalus surgery) and 2 dedicated to emerging future treatment principles (molecular mechanisms of cerebrospinal fluid secretion and hydrocephalus genetics).

Retinal haemorrhage in infants investigated for suspected maltreatment is strongly correlated with intracranial pathology

AIM

To test the two prevailing hypotheses regarding the aetiology of infant retinal haemorrhage: (a) traction forces exerted by the lens and/or corpus vitreum on the retina during infant shaking or (b) retinal vessel leakage secondary to intracranial pathology and raised intracranial pressure.

METHODS

Comparison of medical findings and reported type of trauma in infants investigated for suspected physical abuse with presence (n = 29) or non-presence of retinal haemorrhage (RH) (n = 119).

RESULTS

Intracranial pathology was recorded in 15 (13%) of the non-RH cases and in 27 (97%) of the RH cases (p < 0.0001). All 18 infants with bilateral RH had intracranial pathology. Of 27 infants subjected to witnessed or admitted shaking, two were in the group with RH. One had a single unilateral RH and no intracranial pathology. The other had bilateral RH and intracranial pathology with non-specific white matter changes, acute subdural and subarachnoid haemorrhages, and suspected cortical venous thrombosis. In 15 RH cases, there was no trauma reported and no findings other than RH and intracranial pathology. Accidental blunt head trauma was reported in 7 RH cases.

CONCLUSION

The present study indicates that RH in infants is secondary to intracranial pathology of non-specific aetiology.

Optic Nerve Sheath Diameter Ultrasound: A Non-Invasive Approach to Evaluate Increased Intracranial Pressure in Critically Ill Pediatric Patients

Early diagnosis of increased intracranial pressure (ICP) is crucial for prompt diagnosis and treatment of intracranial hypertension in critically ill pediatric patients, preventing secondary brain damage and mortality. Although the placement of an external ventricular drain coupled to an external fluid-filled transducer remains the gold standard for continuous ICP monitoring, other non-invasive approaches are constantly being improved and can provide reliable estimates. The use of point-of-care ultrasound (POCUS) for the assessment of ICP has recently become widespread in pediatric emergency and critical care settings, representing a valuable extension of the physical examination. The aim of this manuscript is to review and discuss the basic principles of ultra-sound measurement of the optic nerve sheath diameter (ONSD) and summarize current evidence on its diagnostic value in pediatric patients with ICP. There is increasing evidence that POCUS measurement of the ONSD correlates with ICP, thus appearing as a useful extension of the physical examination in pediatrics, especially in emergency medicine and critical care settings for the initial non-invasive assessment of patients with suspected raised ICP. Its role could be of value even to assess the response to therapy and in the follow-up of patients with diagnosed intracranial hypertension if invasive ICP monitoring is not available. Further studies on more homogeneous and extensive study populations should be performed to establish ONSD reference ranges in the different pediatric ages and to define cut-off values in predicting elevated ICP compared to invasive ICP measurement.

Optic nerve ultrasound and cardiopulmonary bypass: A pilot study

Introduction:

Despite advances in surgical, anesthetic, perfusion, and postoperative care, adverse neurological consequences may occur following cardiac surgery and cardiopulmonary bypass (CPB). Consequences of the physiologic effects of CPB may alter the blood–brain barrier, autoregulation, and intracranial pressure (ICP) in the immediate postoperative period.

Methods:

We evaluated the effects of cardiac surgery and CPB on the central nervous system by measuring the optic nerve sheath diameter (ONSD) by using ultrasound as a surrogate marker of ICP. ONSD was measured after anesthetic induction and endotracheal intubation (time 1), after separation from CPB (time 2), and at the completion of the surgical procedure prior to leaving the OR (time 3).

Results:

The study cohort included 14 patients, ranging in age from newborn to 6 years. When comparing the Fontan group (n = 5) to the non-Fontan group (n = 9), four elevated ONSD observations were recorded for the Fontan patients during the study period, including one at time 1, one at time 2, and two at time 3. In Fontan versus non-Fontan patients, ONSD was greater at all three time points compared to non-Fontan. The change in the ONSD from time 1 to time 2 was greater (+0.2 mm vs. −0.1 mm), and the mean value at time 2 was significantly higher (4.2 vs. 3.5 mm, P = 0.048).

Conclusions:

Patients with Fontan physiology may be more prone to higher levels of baseline intracranial pressure due to elevated systemic venous pressure and decreased cardiac output. Alternatively, the chronically high central venous pressures may artificially elevate ONSD without clinical changes in ICP, necessitating the development of separate normative values based on the type of congenital heart disease.

Predictive Value of Optic Nerve Sheath Diameter for Diagnosis of Intracranial Hypertension in Children With Severe Brain Injury

BACKGROUND AND AIMS

Intracranial Hypertension (ICH) is a life-threatening complication of brain injury. The invasive measurement of intracranial pressure (ICP) remains the gold standard to diagnose ICH. Measurement of Optic Nerve Sheath Diameter (ONSD) using ultrasonography is a non-invasive method for detecting ICH. However, data on paediatric brain injury are scarce. The aim of the study was to determine the performance of the initial ONSD measurement to predict ICH occurring in children with severe brain injury and to describe the ONSD values in a control group.

METHODS

In this cross-sectional study, ONSD was measured in children aged 2 months-17 years old with invasive ICP monitoring: before placement of ICP probe and within the 60 min after, and then daily during 3 days. ONSD was also measured in a control group.

RESULTS

Ninety-nine patients were included, of whom 97 were analysed, with a median (IQR) age of 8.7 [2.3-13.6] years. The median (IQR) PIM 2 score was 6.6 [4.4-9.7] and the median (IQR) PELOD score was 21 [12-22]. Aetiologies of brain injury were trauma (n = 72), infection (n = 17) and stroke (n = 8). ICH occurred in 65 children. The median (IQR) ONSD was 5.58 mm [5.05-5.85]. ONSD performed poorly when it came to predicting ICH occurrence within the first 24 h (area under the curve, 0.58). There was no significant difference between the ONSD of children who presented with ICH within the first 24 h and the other children, with a median (IQR) of 5.6 mm [5.1-5.9] and 5.4 mm [4.9-5.8], respectively. Infants aged less than 2 years had a median (IQR) ONSD of 4.9 mm [4.5-5.2], significantly different from children aged more than 2 years, whose median ONSD was 5.6 mm [5.2-5.9]. Age, aetiology or ICP levels did not change the results. Thirty-one controls were included, with a median age of 3.7 (1.2-8.8) years. The median (IQR) of their ONSD measurement was 4.5 mm [4.1-4.8], significantly lower than the patient group.

CONCLUSION

In a paediatric severe brain injury population, ONSD measurement could not predict the 24 h occurrence of ICH. Severity of patients, timing and conditions of measurements may possibly explain these results.

Comparison of B-Scan Ultrasound and MRI-Based Optic Nerve Sheath Diameter (ONSD) Measurements in Children

BACKGROUND

Qualitative, noninvasive assessment of intracranial pressure is of eminent importance in pediatric patients in many clinical situations and can reliably be performed using transorbital ultrasonographic measurement of the optic nerve sheath diameter (ONSD). MRI-based determination of ONSD can serve as an alternative if ultrasound (US) is not possible or available for various reasons, for example, in small, incompliant children. This study investigates repeatability and observer reliability of US ONSD and correlation and bias of US- versus MRI-based ONSD assessment in pediatric patients.

METHODS

One hundred fifty children diagnosed with tumor (n = 40), hydrocephalus (n = 42), and other cranial pathologies (n = 68) were included. Bilateral ONSD was quantified by US using a 12-MHz linear array transducer. This was compared with ONSD measured in simultaneously acquired (≤24 h) T2-weighted MRI scans of the orbit.

RESULTS

Repeatability of individual US values and intraobserver ONSD was outstanding (Cronbach's α = 0.984 and 0.996, respectively). Overall mean values for ONSD were 5.8 ± 0.88 mm and 5.7 ± 0.89 mm for US and MRI, respectively. Correlation between US and MRI-based ONSD was strong (r = 0.976, P < 0.01). Bland and Altman analysis showed a mean bias of 0.078 mm. A repeated-measures correlation (r_rm) in 9 patients showed an excellent value (r_rm = 0.94, P < 0.01).

CONCLUSIONS

Repeatability and reliability of US ONSD determination is excellent. In case US ONSD assessment is not possible or available, MRI scans can serve as an excellent alternative. The difference of US and MRI ONSD is minimal and insignificant, and thus, both techniques can complement each other.

The association between intracranial pressure and optic nerve sheath diameter on patients with head trauma

BACKGROUND

Although intracranial pressure (ICP) monitoring is the gold standard method for measuring intracranial pressure after traumatic brain injury, optic nerve sheath diameter (ONSD) measurement with ultrasound (US) is also used in the evaluation of ICP.

OBJECTIVE

To investigate the association between a series of OSND measurements by US and changes in clinical presentation of the patient.

METHODS

Prospective study including 162 patients with traumatic brain injury. Age, sex, cerebral CT findings, ONSD levels by US at minutes 0, 60, and 120, Glasgow Coma Scale (GCS) within same period, change of consciousness, treatment, and mortality data were reviewed. The association of ONSD levels with GCS, change of consciousness, treatment, and mortality was evaluated.

RESULTS

There was no difference in ONSD changes in the patients' sample within the period (p=0.326). ONSD significantly increased in patients who died (p<0.001), but not in those who survived (p=0.938). There was no significant change in ONSD of the patients who received anti-edema therapy (p=801), but significantly increased ONSD values were found in those who received anti-edema therapy (p=0.03). Patients without change of consciousness did not have any significant change in ONSD (p=0.672), but ONSD values increased in patients who consciousness became worse, and decreased in those who presented a recovery (respectively, p<0.001, p=0.002). A negative correlation was detected between ONSD values and GSC values measured at primary, secondary, and tertiary time periods (for all p<0.001).

CONCLUSIONS

ONSD follow-up may be useful to monitor ICP increase in patients with acute traumatic brain injury.

Ventriculomegaly in children: nocturnal ICP dynamics identify pressure-compensated but active paediatric hydrocephalus

INTRODUCTION

Paediatric ventriculomegaly without obvious signs or symptoms of raised intracranial pressure (ICP) is often interpreted as resulting from either relative brain atrophy, arrested "benign" hydrocephalus, or "successful" endoscopic third ventriculostomy (ETV). We hypothesise that the typical ICP "signature" found in symptomatic hydrocephalus can be present in asymptomatic or oligosymptomatic children, indicating pressure-compensated, but active hydrocephalus.

METHODS

A total of 37 children fulfilling the mentioned criteria underwent computerised ICP overnight monitoring (ONM). Fifteen children had previous hydrocephalus treatment. ICP was analysed for nocturnal dynamics of ICP, ICP amplitudes (AMP), magnitude of slow waves (SLOW), and ICP/AMP correlation index RAP. Depending on the ONM results, children were either treated or observed. The ventricular width was determined at the time of ONM and at 1-year follow-up.

RESULTS

The recordings of 14 children (group A) were considered normal. In the 23 children with pathologic recordings (group B), all ICP values and dependent variables (AMP, SLOW) were significantly higher, except for RAP. In group B, 12 of 15 children had received a pre-treatment and 11 of 22 without previous treatment. All group B children received treatment for hydrocephalus and showed a significant reduction of frontal-occipital horn ratio at 1 year. During follow-up, a positive neurological development was seen in 74% of children of group A and 100% of group B.

CONCLUSION

Ventriculomegaly in the absence of signs and symptoms of raised ICP was associated in 62% of cases to pathological ICP dynamics. In 80% of pre-treated cases, ETV or shunt failure was found. Treating children with abnormal ICP dynamics resulted in an outcome at least as favourable as in the group with normal ICP dynamics. Thus, asymptomatic ventriculomegaly in children deserves further investigation and, if associated with abnormal ICP dynamics, should be treated in order to provide a normalised intracranial physiology as basis for best possible long-term outcome.

Evaluation of the relationship between NIRS (near-infrared spectroscopy) and optic nerve sheath diameter measurement in children with increased intracranial pressure: a pilot study

Background

The increased intracranial pressure (ICP) syndrome may emerge depending on many different neurological factors and the early diagnosis and treatment are important for the prevention of neurologic damage and related mortality. In recent years, the follow-up of increased ICP with non-invasive methods has been rising. In this study, our objective was to determine the significance and any possible correlation between Optic Nerve Sheath Diameter (ONSD) and Near Infrared Spectroscopy (NIRS) in children with increased ICP.

Methods

Patients who were hospitalized in our pediatric ICU at Çukurova University Medical Faculty between June 2018 and June 2019 due to the suspicion of increased ICP were included in this study. The demographic characteristics of patients, diagnosis at admission, results of the cranial CT and MRI examinations, and results of the simultaneous ONSD and NIRS measurements were recorded.

Results

A total of 36 patients were included in our study. With respect to the diagnosis, non-traumatic causes were at the forefront in 30 patients (83.3%), and the most common causes were meningoencephalitis (n = 9; 25%) and non-traumatic bleeding (n = 7; 19.4%). Six of the patients were under the age of one year (16.7%), and the mean values of ONSD and NIRS were 4.8 ± 0.7 mm and 71.1 ± 12.4% respectively in this group. Fourteen patients were in the one to ten year age group and the mean values of ONSD and NIRS were 6.1 ± 0.6 mm and 72.7 ± 9.3% respectively. Sixteen patients were over ten years of age (44.4%), and the mean values of ONSD and NIRS were 5.6 ± 0.7 mm and 74.2 ± 16% respectively. There was no correlation between the ONSD and NIRS values (r:0.307; p = 0.068).

Conclusion

Our study showed that ONSD measurements were helpful in children with increased ICP and reflected the increase in ICP. However, our study also demonstrated that ONSD was not in correlation with the NIRS monitoring. We believe that there is a need for further studies focused on the use of ONSD and NIRS in the monitoring of increased ICP.

Is Ocular Sonography a Reliable Method for the Assessment of Elevated Intracranial Pressure in Children?

Point-of-care ultrasound has been widely used by clinicians at the bedside in recent years. Various types of point-of-care ultrasound practices are employed, especially in pediatric emergency rooms and intensive care units. Pediatric intensive care specialists perform point-of-care ultrasound virtually as a part of physical examination since it provides just-in-time vital clinical information, which could assist in acute management strategies in critically ill patients. Measurement of optic nerve sheath diameter using point-of-care ultrasound is a noninvasive and radiation-free technique to determine raised intracranial pressure. Ophthalmic artery and central retinal artery Doppler indices can be used as transcranial Doppler to assess raised intracranial pressure. The aim of this review was to provide detailed information on ultrasonographic measurements of optic nerve sheath diameter and central retinal artery Doppler indices as techniques of interest for predicting increased intracranial pressure in pediatric patients in view of the literature.

Decrease of Coronal Optic Nerve Sheath Diameter is Associated With Postoperative Cognitive Decline in Patients Undergoing Carotid Endarterectomy

OBJECTIVE

Patients undergoing carotid endarterectomy (CEA) have a significant possibility of developing postoperative cognitive decline (POCD). POCD after surgery could be result from cerebral hypotension induced by cross-clamping or postoperative hyperperfusion. Optic nerve sheath diameter (ONSD) exhibits an excellent correlation with invasive intracranial pressure monitoring, Here, the authors explored the risk factors of POCD in patients undergoing CEA, paying close attention to ONSD to test the hypothesis that decrease of coronal ONSD was related to the incidence of POCD.

DESIGN

Observational retrospective review.

SETTING

Single tertiary academic center.

PARTICIPANTS

One hundred sixteen patients undergoing CEA from January 1, 2019 to December 31, 2019.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

A multivariate logistic regression, scatter diagrams, and a receiver operating curve were used to evaluate the ability to predict POCD though the change in coronal ONSD. This study ultimately enrolled 84 patients and the incidence of POCD within postoperative two days was 28.6%. Decrease of coronal ONSD (odds ratio [OR], 0.438; 95% confidence interval [CI] 0.217-0.881; p = 0.021) and total intravenous anesthesia (TIVA) (OR, 25.541, 95% CI 2.100-310.614, p = 0.011) were independent risk factors for POCD. Changes in coronal ONSD had an area under the curve to distinguish POCD of 0.716 (95% CI 0.531-0.902). Using a cutoff of 0.05 cm, changes of coronal ONSD had a sensitivity of 66.7% and specificity of 66.7%.

CONCLUSIONS

Decrease of coronal ONSD, measured by ultrasonography and TIVA, were associated with POCD. Change in coronal ONSD was a moderate predictor of incidence of POCD.

Intracranial pressure based decision making: Prediction of suspected increased intracranial pressure with machine learning

Background

Repeated invasive intracranial pressure (ICP) monitoring is desirable because many neurosurgical pathologies are associated with elevated ICP. On the other hand, it could become a risk for children to repeat sedation, anesthesia, or radiation exposure. As a non-invasive method, measurements of optic nerve sheath diameter (ONSD) has been revealed to accurately predict increased ICP. However, no studies have indicated a relationship among age, brain, and ventricular parameters in normal children, nor a prediction of increased ICP with artificial intelligence.

Methods and findings

This study enrolled 400 normal children for control and 75 children with signs of increased ICP between 2009 and 2019. Measurements of the parameters including ONSD on CT were obtained. A supervised machine learning was applied to predict suspected increased ICP based on CT measurements. A linear correlation was shown between ln(age) and mean ONSD (mONSD) in normal children, revealing mONSD = 0.36ln(age)+2.26 (R² = 0.60). This study revealed a linear correlation of mONSD measured on CT with ln(age) and the width of the brain, not the width of the ventricles in 400 normal children based on the univariate analyses. Additionally, the multivariate analyses revealed minimum bicaudate nuclei distance was also associated with mONSD. The results of the group comparison between control and suspected increased ICP revealed a statistical significance in mONSD and the width of the ventricles. The study indicated that supervised machine learning application could be applied to predict suspected increased ICP in children, with an accuracy of 94% for training, 91% for test.

Conclusions

This study clarified three issues regarding ONSD and ICP. Mean ONSD measured on CT was correlated with ln(age) and the width of the brain, not the width of the ventricles in 400 normal children based on the univariate analyses. The multivariate analyses revealed minimum bicaudate nuclei distance was also associated with mONSD. Mean ONSD and the width of ventricles were statistically significant in children with signs of elevated ICP. Finally, the study showed that machine learning could be used to predict children with suspected increased ICP.

Correlation between the total number of features of paediatric pseudotumour cerebri syndrome and cerebrospinal fluid pressure

PURPOSE

Accurate diagnosis of pseudotumour cerebri syndrome (PTCS) in children is challenging. We aimed to see if the clinical and radiological assessment that is carried out before lumbar puncture could predict subsequently recorded CSF pressures, and thus whether it could be used to increase diagnostic certainty of paediatric PTCS.

METHODS

We used internationally recognised diagnostic criteria to derive a list of clinical, brain neuroimaging and venography features that were accepted to be associated with a diagnosis of PTCS. We performed a retrospective cohort study of children referred to our centre with suspected PTCS, identifying the presence or absence of those features for each child at initial presentation. The sum total scores of the features that were present were correlated with the child's recorded CSF pressure.

RESULTS

The sum total scores were significantly positively correlated with recorded CSF pressures. The positive correlation was seen when clinical and brain neuroimaging features were included alone, and the correlation was slightly stronger when venography features were included in addition.

CONCLUSION

Calculating the sum total of clinical, brain neuroimaging and venography features (where venography is performed) present at initial presentation can help in the management of children under investigation for PTCS. Children with high scores are more likely to have severely raised CSF pressures and thus may warrant more urgent LP investigations. By contrast, in children with subtle abnormalities in optic disc appearance such that disc oedema cannot be ruled out, a low score may add further reassurance and less urgency to proceed to LP.

Ultrasonographic Optic Nerve Sheath Diameter Measurement to Detect Intracranial Hypertension in Children With Neurological Injury: A Systematic Review

OBJECTIVES

Ultrasound measured optic nerve sheath diameter is a noninvasive, nonirradiating tool for estimating intracranial hypertension. The objective of this systematic review and meta-analysis is summarization of the current evidence for accuracy of ultrasound measured optic nerve sheath diameter in detecting intracranial hypertension in pediatric patients.

DATA SOURCES

Medical subject heading terms were used to search MEDLINE, Embase, Google Scholar, Web of Science, and the Cochrane Library for relevant citations. Publications from January 1, 2000, to June 30, 2019, were included in the search strategy.

STUDY SELECTION

Studies were included if they involved patients less than 18 years, where ultrasound measured optic nerve sheath diameter was compared to conventional, nonophthalmic tests for intracranial hypertension. Studies were excluded if there was insufficient data to compute a sensitivity/specificity table. Case reports, case series, and manuscripts not published in English were also excluded.

DATA EXTRACTION

The initial search returned 573 citations. Of these, 57 were selected for review.

DATA SYNTHESIS

Eleven citations were included in the final meta-analysis. A bivariate random-effects meta-analysis was performed, which revealed a pooled sensitivity for ultrasound measured optic nerve sheath diameter of 93% (95% CI, 74-99%), a specificity of 74% (95% CI, 52-88%), and a diagnostic odds ratio of 39.00 (95% CI, 4.16-365.32). The area under the curve of the hierarchical summary receiver operating characteristic curve was 0.90 (95% CI, 0.87-0.93). Subgroup analyses of the test's performance evaluating new-onset intracranial hypertension and in comparison to invasively measured intracranial pressure were performed. The test performance in these instances was similar to findings in the primary analysis.

CONCLUSIONS

We are unable to identify a threshold value in ultrasound measured optic nerve sheath diameter for the determination of intracranial hypertension in children. Even though the ultrasound measured optic nerve sheath diameter measurement is highly sensitive to the presence of increased intracranial pressure, the test has only moderate specificity. Therefore, other confirmatory methods and further investigation is necessary in the clinical care of children. The technique is likely not sufficiently precise for clinical use in the absence of other confirmatory methods, and further investigation is necessary to determine clinical protocols for its use in children.

Point-of-care ultrasound of optic nerve sheath diameter to detect intracranial pressure in neurocritically ill children - A narrative review

The rapid diagnosis of increased intracranial pressure is urgently needed for therapeutic reasons in neurocritically ill children, however this can rarely be achieved without invasive procedures. Point-of-care ultrasound of the optic nerve sheath diameter has been proposed as a non-invasive and reliable means to detect increased intracranial pressure in adults. Accordingly, clinicians may be able to use this technique to initiate early treatment and monitor the effectiveness of treatment in conjunction with other clinical examination and diagnostic modalities. Two meta-analyses and a systematic review have been published on this topic in adults. However, data on the correlation between optic nerve sheath diameter and intracranial pressure in neurocritically ill children are scarce. The aim of this review was to briefly describe what is being measured with point-of-care ultrasound of the optic nerve sheath diameter, summarize the most recent findings from adult literature, and provide an update of current work in children.

The relation of optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in pediatric neurosurgery practice - Part II: Influence of wakefulness, method of ICP measurement, intra-individual ONSD-ICP correlation and changes after therapy

PURPOSE

Previous studies correlating ultrasound (US)-based optic nerve sheath diameter (ONSD) and intracranial pressure (ICP) in children were performed under general anesthesia. To apply ONSD in daily clinical routine, it is necessary to investigate patients awake. It is furthermore essential for ICP-assessment with ONSD to know if ONSD-ICP correlation varies within individuals. In this study, we report on the influence of wakefulness, method of ICP measurement, intraindividual correlations, and dynamic changes of ONSD and ICP after ICP decreasing therapy.

METHODS

The overall study included 72 children with a median age of 5.2 years. US ONSD determination was performed immediately prior to invasive ICP measurement, and the mean binocular ONSD was compared to ICP. In 10 children, a minimum of 3 ONSD/ICP measurements were performed to investigate a correlation within subjects. In 30 children, measurements were performed before and after therapy.

RESULTS

Twenty-eight children were investigated awake with an excellent correlation of ONSD and ICP (r = 0.802, p < 0.01). In 10 children, at least three simultaneous ONSD and ICP measurements were performed. The intraindividual correlations were excellent (r = 0.795-1.0) however with strongly differing individual regression curves. The overall correlation within subjects was strong (r = 0.78, p < 0.01). After ICP decreasing therapy, all ONSD values decreased significantly (p < 0.01); however, there was no correlation between ∆ICP and ∆ONSD.

CONCLUSION

Awake investigation does not impair the correlation between ONSD and ICP. Even if there is a good overall ONSD-ICP correlation, every individual has its own distinctive and precise correlation line. The relationship between ONSD and ICP is furthermore not uniform between individuals. Strong ICP decreases can lead to smaller ONSD changes and vice versa. This should be kept in mind when using this technique in the clinical daily routine.