Ultrasonographic Optic Nerve Sheath Diameter Research Articles

Ultrasonographic Measurement of Optic Nerve Sheath Diameter in Patients with Traumatic Head Injury: A Prospective Observational Study

Introduction: The early detection of elevated intracranial pressure is crucial for guiding interventions and improving patient outcomes in head injury patients. The intracranial pressure assessment with invasive intracranial devices is the gold standard. These devices however has a risk of infection, bleeding and dislodgement. Optic nerve sheath diameter measurement using ultrasonography has emerged as a promising method for indirect intracranial pressure estimation. Aims: To observe the changes in optic nerve sheath diameter over period of time, and to correlate the optic nerve sheath diameter with computed tomography findings of raised intracranial pressure in traumatic head injury. Methods: A prospective cross-sectional time series study was conducted at Nepalgunj Medical College to assess the utility of ultrasonography measurement of optic nerve sheath diameter in patients with head injuries from August 2023 to January 2024. Forty-nine patients with head injuries were included in the study. The ultrasonographic optic nerve sheath diameter measurements were obtained at admission, 48 hours post-admission, and 1 month post-head injury. The clinical parameters including Glasgow Coma Scale and radiological findings from Computed Tomography head were recorded. Results: Forty nine patients were enrolled in the study. Among them, 44.90% (27) were male and 55.10% (22) were female. Age ranged from 5 to 66 years, with a mean of 33.94 ± 15.27 years. The mean optic nerve sheath diameter was 5.24±0.86 mm at admission which decreased to 4.31±0.62 mm at 48 hours and 4.02±0.47 mm at 1 month. Our study showed significant reduction in optic nerve sheath diameter after conservative or surgical treatment in patients with head injury (F = 27.017; P =0.002) Conclusion: The ultrasonographic measurement of optic nerve sheath diameter proved to be a valuable tool in monitoring intracranial pressure in patients with head injuries.

Evaluation of the effect of trendelenburg position duration on intracranial pressure in laparoscopic hysterectomies using ultrasonographic optic nerve sheath diameter measurements

BackgroundDuring laparoscopic surgery, pneumoperitoneum and Trendelenburg positioning applied to provide better surgical vision can cause many physiological changes as well as an increase in intracranial pressure. However, it has been reported that cerebral autoregulation prevents cerebral edema by regulating this pressure increase. This study aimed to investigate whether the duration of the Trendelenburg position had an effect on the increase in intracranial pressure using ultrasonographic optic nerve sheath diameter (ONSD) measurements.MethodsThe near infrared spectrometry monitoring of patients undergoing laparoscopic hysterectomy was performed while awake (T0); at the fifth minute after intubation (T1); at the 30th minute (T2), 60th minute (T3), 75th minute (T4), and 90th minute (T5) after placement in the Trendelenburg position; and at the fifth minute after placement in the neutral position (T6). Results: The study included 25 patients. The measured ONSD values were as follows: T0 right/left, 4.18±0.32/4.18±0.33; T1, 4.75±0.26/4.75±0.25; T2, 5.08±0.19/5.08±0.19; T3, 5.26±0.15/5.26±0.15; T4, 5.36±0.11/5.37±0.12; T5, 5.45±0.09/5.48±0.11; and T6, 4.9±0.24/4.89±0.22 ( p < 0.05 compared with T0). ). No statistical difference was detected in all measurements in terms of MAP, HR and ETCO2 values compared to the T0 value (p > 0.05).ConclusionsIt was determined that as the Trendelenburg position duration increased, the ONSD values ​​increased. This suggests that as the duration of Trendelenburg positioning and pneumoperitoneum increases, the sustainability of the mechanisms that balance the increase in intracranial pressure becomes insufficient.Trial registrationThis study was registered at Clinical Trials.gov on 21/09/2023 (registration number NCT06048900).

Letter to the Editor Regarding “Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis”

Letter to the Editor Regarding “Optic Nerve Sheath Diameter Sonography for the Diagnosis of Intracranial Hypertension in Traumatic Brain Injury: A Systematic Review and Meta-Analysis”

Effect of Neck Rotation With Flexion on Ultrasonographic Optic Nerve Sheath Diameter in Patients Undergoing Elective Craniotomy.

Background Extreme neck positioning to facilitate craniotomy can result in impaired venous drainage from the brain and a subsequent rise in increased intracranial pressure (ICP). The effects of varied neck positioning intraoperatively on ultrasonographic optic nerve sheath diameter (USG-ONSD) are still unexplored. This study aims to quantify the angle of neck rotation and flexion that can cause a significant increase in USG-ONSD in patients undergoing elective craniotomy. Methods A total of 100 patients were recruited in this non-randomized study and equally divided into two groups. In one group, patients with neck rotation ≤30 degrees and in another group, patients with neck rotation >30 degrees with varying degrees of neck flexion were included. The average of three USG-ONSD measurements in both eyes was obtained and compared in both groups at baseline, after positioning, and at the end of the surgery after making the neck neutral. Results The results of 100 recruited patients were analyzed. All the patients had neck flexion in the range of40° to 45°, whereas the neck rotation ranged from 10° to 45°. The USG-ONSD of both eyes changed significantly from baseline to post-positioning time point in patients with neck rotation >30° (right eye p=0.038, left eye p=0.04) when compared to neck rotation ≤30°. There was no significant change in USG-ONSD from baseline to the postoperative time point after making the neck neutral (right eye p=0.245, left eye p=0.850) in both groups. Conclusions This study demonstrates that USG-ONSD, a surrogate measure of ICP, increased significantly after neck flexion with rotation >30° in neurosurgical patients. However, USG-ONSD becomes comparable to baseline after putting the patient's neck in a neutral position after surgery.

Assessment of diagnostic accuracy of ultrasonographic optic nerve sheath diameter measurement in identifying raised ICP in TBI patients

ABSTRACT This systematic review evaluates the diagnostic accuracy of ultrasonographic optic nerve sheath diameter (ONSD) measurement for detecting elevated intracranial pressure (ICP) in traumatic brain injury (TBI) patients. A comprehensive search identified 1,234 articles, with 10 meeting inclusion criteria. These studies demonstrated high sensitivity (88-95%) and specificity (80-90%) for ultrasonographic ONSD, underscoring its potential as a reliable, non-invasive method for assessing elevated ICP in emergency and critical care settings. However, variability in measurement techniques and operator expertise highlights the need for standardized protocols. Further research with larger sample sizes, standardized protocols, and long-term evaluations is necessary to confirm its diagnostic utility and ensure accuracy across diverse patient populations.

Additional predictive value of optic nerve sheath diameter for neurological prognosis after cardiac arrest: a prospective cohort study

BackgroundThe goal is to estimate the additional value of ultrasonographic optic nerve sheath diameter (ONSD) measurement on days 1–3, on top of electroencephalography (EEG), pupillary light reflexes (PLR), and somatosensory evoked potentials (SSEP), for neurological outcome prediction of comatose cardiac arrest patients. We performed a prospective longitudinal cohort study in adult comatose patients after cardiac arrest. ONSD was measured on days 1–3 using ultrasound. Continuous EEG, PLR, and SSEP were acquired as standard care. Poor outcome was defined as cerebral performance categories 3–5 at 3–6 months. Logistic regression models were created for outcome prediction based on the established predictors with and without ONSD. Additional predictive value was assessed by increase in sensitivity for poor (at 100% specificity) and good outcome (at 90% specificity).ResultsWe included 100 patients, 54 with poor outcome. Mean ONSD did not differ significantly between patients with good and poor outcome. Sensitivity for predicting poor outcome increased by adding ONSD to EEG and SSEP from 25% to 41% in all patients and from 27% to 50% after exclusion of patients with non-neurological death.ConclusionsONSD on days 1–3 after cardiac arrest holds potential to add to neurological outcome prediction.Trialregistration: clinicaltrials.gov, NCT04084054. Registered 10 September 2019, https://www.clinicaltrials.gov/study/NCT04084054.

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.

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

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. 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. Expert ONSD measurements and CNN-derived ONSD estimates had strong agreement (r = 0.7, p < .0001). The expert mean ONSD (standard deviation) is 5.27mm (0.43) compared to CNN mean estimate of 5.46mm (0.37). Mean difference (95% confidence interval, p value) is 0.19mm (0.10-0.27mm, p = .0011), and root mean square error is 0.27mm. A CNN can learn ONSD measurement using masking without image segmentation or landmark detection.

Bir Pilot Çalışma: Kritik Hasta Yönetimi İçin Ölçülen Sonografik Optik Sinir Kılıfı Kalınlığına COVID-19'un Etkisi

Objective: The aim of this study is to evaluate the effects of the Coronavirus disease 2019 on sonographic optic nerve sheath diameter measurement and thus avoid possible misleading results in clinical practice.&#x0D; Material and Method: Each volunteer was first evaluated using carotid system color Doppler ultrasonography. Patients with a history of PCR-confirmed Coronavirus disease 2019 infection were classified as group 1 and patients without a history of Coronavirus disease 2019 infection were classified as group 2, and sonographic optic nerve sheath diameter values of both groups were analyzed.&#x0D; Results: Of the 123 patients included in the study, 70 (56.9%) were female and 58 (43.1%) were male. 83 (67.5%) of the patients included in the study were in group 1 and 40 (32.5%) were in group 2. The mean sonographic optic nerve sheath diameter values for the groups were 3.53 mm and 3.46 mm, respectively. The sonographic optic nerve sheath diameter differences between the two eyes for the groups were determined to be 0.203±0.139 mm and 0.282±0.2 mm.&#x0D; Conclusion: Due to the variable effects of Severe Acute Respiratory Syndrome Coronavirus-2, the use of sonographic optic nerve sheath diameter measurement in current standards for critical patient management may lead to false-positive or false-negative results.

Optic Nerve Sheath Diameter: A Cross-Sectional Study of Ultrasonographic Measurement in Healthy Black South African Adults.

Ultrasonographic optic nerve sheath diameter (ONSD) measurement is an accurate, portable, and non-invasive method of detecting raised intracranial pressure that can also reflect dynamic, real-time changes in intracranial pressure fluctuations. Various studies have shown the mean range of ONSD to vary greatly across different population groups. This study aimed to determine the mean ONSD in healthy Black South African adults. In this cross-sectional study, healthy black South African adult participants underwent optic nerve sheath ultrasound of the right eye, with the diameter being measured at 3 mm behind the retina in two different planes. The average of the two measurements was used to find the mean optic nerve sheath diameter. This measurement was compared to that found in a Canadian adult population, and the effect of age, gender, and co-morbidities on ONSD was assessed. A total of 99 participants were included in this study, of which 39 were male and 60 were female. The mean ONSD was found to be 5.1 mm (SD ± 0.33). This value was significantly higher than the mean ONSD observed in the Canadian population (p < 0.001). There was no significant difference found between the mean ONSD in males and females (p = 0.652), and both age and presence of co-morbidities were not found to significantly correlate with ONSD. (p = 0.693 and p = 0.974, respectively).

A prospective observational study on evaluating the efficacy of bedside optic nerve sheath diameter in assessing clinical progression of patients admitted in neurosurgical ICU with comparisons to CT scans and GCS score

Background: Ultrasound of the optic nerve sheath diameter (ONSD) is a non-invasive, repeatable tool that can be used to measure intracranial pressure in a dynamic way with high diagnostic accuracy. The goal of this study was to find out if a bedside ultrasonographic measurement of optic nerve sheath diameter (ONSD) can accurately predict the computed tomography (CT) findings of high intracranial pressure (ICP) and changes to the Glasgow Coma Scale (GCS) in adult head injury patients in the Neurosurgery ICU. Methods: For 54 patients in the neurosurgical intensive care unit, we conducted a retrospective analysis of the results of cranial ultrasounds. Those under the age of 18 and those with apparent visual injuries were ineligible. Both horizontal and vertical optic nerve sheath diameters were measured 3 mm beneath the globe in each eye using a 7.5-10MHz ultrasonographic probe. A binocular change in optic nerve sheath diameter of more than 2.00 mm was deemed abnormal in two consecutive readings in the same patient. Patients in the neurosurgical ICU were given a GCS score, which was used to classify their level of brain damage as mild, moderate, or severe. The accuracy of the optic nerve sheath diameter was evaluated using cranial CT findings of shift, oedema, or effacement that suggested an increased intracranial pressure. Results: The research has 54 participants. According to the results, 68.5% of those who took the study were men, while 31.5% of those who did so were women. Nearly 16.7 per cent of respondents were between the ages of 18 and 40, while 40.7% of respondents were between the ages of 40 and 60, and 42.6% of respondents were above 60. The significant change in ONSD- fall in GCS and CT-progression scan-findings correlation was very strong. When compared to CT scan progression, the ONSD bedside sonographic test had an 86.7% sensitivity and an 89.7% specificity for detecting elevated ICP. The Positive Predictive Value of the reduction in GCS with advancement in CT scan was 80% and the Negative Predictive Value was 89.7%, respectively. Conclusions: The sensitivity, specificity, and positive predictive value of bedside ONSD ultrasonography in predicting high intracranial pressure are significant to those of progression in CT scan and drop in GCS. An ONSD bedside measurement may be used to determine elevated ICP since it is non-invasive and repeatable.

Is optic nerve sheath diameter diagnostic in methanol intoxication?

Background and aimMethyl alcohol intoxication causes severe morbidity and mortality, especially in developing countries. Formic acid is formed as a result of methanol metabolism. Formic acid accumulation and inhibition of adenosine triphosphate synthesis result in ophthalmic issues. This study aimed to demonstrate that the optic nerve sheath diameter (ONSD) measurement is an accurate prognostic marker and can be helpful in the diagnosis of methanol intoxication. Materials and methodsThis prospective study was conducted with 52 patients who were admitted to the emergency department after alcohol consumption and agreed to participate in the study. Age, gender, comorbid diseases, vital signs, ONSD ultrasonography measurements, hospitalization and discharge status, in-hospital mortality status, dialysis need, presence of visual impairment, blood gas parameters, respiratory status, time since alcohol intake, ethanol levels, urea levels, and creatinine levels were analyzed. ResultsROC curve analysis was performed to evaluate the predictive power of ONSD to diagnose methanol intoxication. The area under the curve was 0.857 for the cut-off value of 5.05 mm (95 % CI: 0.728–0.985; p < 0.001), with a sensitivity of 80.8 % and a specificity of 100 %. In the regression analysis performed to determine the prognostic value of the parameters in estimating mortality in methanol intoxication cases, an increase in ONSD (OR: 3.619; 95 % CI: 0.057–0.199; p = 0.001), an increase in lactate levels (OR: 5.653; 95 % CI: 0.040–0.085; p < 0.001), and increased duration after alcohol intake (OR: 2558; 95 % CI: 0.004–0.034; p = 0.014) were identified as independent predictors of mortality, but pH, HCO3, and base deficit levels were not significant predictors. ConclusionsWe believe that ONSD can be helpful for the differential diagnosis and prognosis of patients with suspected methanol toxicity who presented with alcohol intake.

Prognostic role of optic nerve sheath diameter in stroke in emergency department, A case control study.

Sonographic measurement of optic nerve sheath diameter (ONSD) can reflect intracranial pressure (ICP) indirectly and determine the neurology intensive care unit (NICU) requirement and mortality in acute ischemic stroke (AIS). To demonstrate the effectiveness of ONSD to determine mortality, morbidity, and NICU requirement on patients with the AIS. The sonographic ONSD measurements were performed on each patient with AIS, over 18 years old. All patients were categorized according to the Oxfordshire Community Stroke Project (OCSP) classification system. MRI images were examined for increased ICP, and the patients were categorized into two groups as increased ICP (i-ICP) and normal ICP. The ONSD results were evaluated in terms of classifications, outcomes, and prognosis of the patients. One hundred and five patients were included and 31 (35.2%) were in the i-ICP group. The median ONSDs were 5.26 mm in the i-ICP group and 4.62 mm in the normal ICP group (P < 0.001). The median ONSDs were 5.13 mm in the NICU group and 4.69 mm in the neurology ward (NW) group (P = 0.001). The total anterior circulation infarction (TACI) subgroup had higher ONSDs than the others (TACI: 5.27 mm; PACI: 4.73 mm; POCI: 4.77 mm; and LACI: 4.64 mm, P < 0.001). The NICU requirements were higher in the TACI subgroup. The median ONSD was 5.42 mm in the deceased group (survived: 4.77 mm, P < 0.001). ONSD may be favorable for predicting the increased ICP and the NICU requirement in OCSP subgroups. Moreover, ONSD can be used to foresee the mortality of AIS.

Comparison of extraperitoneal and intraperitoneal laparoscopic procedures for intracranial pressure increase: a prospective clinical study.

According to the literature, higher levels of both intracranial pressure (ICP) and intraabdominal pressure (IAP) are related in a way that suggests a causal relationship. An increase in ICP can cause major neurological problems both during and after laparoscopic surgery. In this study, we aimed to examine the increase in ICP between totally extraperitoneal (TEP) inguinal hernia repair and laparoscopic cholecystectomy. We investigated 52 individuals who underwent laparoscopic surgery for the treatment of inguinal hernia (n = 26) or had a laparoscopic cholecystectomy (n = 26). The optic nerve sheath diameter (ONSD) was assessed before the procedure (T0), 10 minutes after carbon dioxide insufflation (T1), and immediately before extubation (T2). There were significant differences in the ONSD values between the two groups as a function of time (p = 0.001). In terms of ONSD, the laparoscopic cholecystectomy value (LV) group showed a greater shift from T0 to T1 and T2 than the inguinal hernia value (HV) group. At T1, the ONSD values of both groups were considerably higher than those of T0 and T2. The impact of the extraperitoneal and transperitoneal laparoscopic methods on ICP was investigated. The ONSD value reached its maximum at T1 in both groups. At all measurement periods, the ONSD values of the LV group were noticeably higher than those of the HV group. The diagnostic accuracy of ONSD ultrasonography is an important approach for determining the ICP level. During the decision-making process of TEP inguinal hernia repair, this study can guide medical professionals in the evaluation of elevated ICP.

Evaluation of Optic Nerve Sheath Diameter Measurement in the Management of Patients Admitted to the Emergency Department with Head Trauma

Objective: Ultrasonographic measurements of optic nerve sheath diameter is associated with increased intracranial pressure. Intracranial pressure measurements are usually performed on critical areas or intensive care unit patients. The effect of ultrasonographic measurement of optic nerve sheath diameter in predicting pathology or the need for surgery in mild or moderate head trauma has not been evaluated. In our study, we compared ultrasonographic optic nerve sheath diameter measurements with cranial computed tomography (CT) findings and clinical outcomes of patients with head trauma. Materials and methods: Patients with head trauma admitted to the emergency department who were diagnosed with mild, moderate, and severe brain injury were selected for this retrospective study. The optic nerve sheath diameters were measured by ultrasonography. The findings were compared with the outcome and cranial tomography characteristics of the patients. Results: Of the 58 patients admitted to the emergency department with head trauma, mild traumatic brain injury was most common. Hospitalization or operation was required in 51.7% of the patients (30 patients). The mean optic nerve sheath diameter was 4.96 ± 1.02 mm (3.1–7.3 mm) on the right and 4.92 ± 1.02 mm (3.3–7.8) on the left. Optic nerve sheath diameter of 5 mm or more were statistically significant in predicting hospitalization, the presence of pathology, and increased intracranial pressure on cranial CT (P &lt; 0.05). Conclusion: Optic nerve sheath diameters of patients with moderate and mild head trauma may provide information about the need for hospitalization or surgery and can be used as a triage criterion in determining the need for monitoring and follow-up and imaging priorities.

Effect of internal jugular vein catheterization on intracranial pressure and postoperative cognitive function in patients undergoing robot-assisted laparoscopic surgery.

We aimed to evaluate the effects of internal jugular vein (IJV) catheterization on intracranial pressure (ICP) and postoperative delirium (POD) during robot-assisted laparoscopic surgery by measuring the optic nerve sheath diameter (ONSD). Data from a prospective single-center cohort study, conducted from October 2021 to February 2022, were used. Forty out of 80 patients scheduled for laparoscopic radical hysterectomy or prostatectomy were assigned to the group receiving IJV catheterization (Group I), and the other 40 only received peripheral venous cannulation (Group C) according to clinical need of patients. Ultrasonography of ONSDs, the proportion of regurgitation time in a cardiac cycle, and hemodynamic parameters were measured at four time points: immediately after induction of anesthesia in the supine position (T0), 30 min (T1), 60 min (T2) after orienting to the Trendelenburg position, and before returning to the supine position at the end of surgery (T3). Time to eye opening and emergence stay, POD, and QoR-15 were compared. The ONSDs increase gradually as the surgery progressed. Group I showed a higher value of ONSD at T1 (4.72 ± 0.29 mm vs. 4.5 ± 0.33 mm, p = 0.0057) and T3 (5.65 ± 0.33 mm vs. 5.26 ± 0.31 mm, p < 0.0001). The proportions of the regurgitation time of IJVV were greater in Group I than those in Group C at T1 (14.95, 8.5%-18.9% vs. 9.6%, 0%-17.2%, p < 0.0001) and T3 (14.3, 10.6%-18.5% vs. 10.4%, 0%-16.5%, p = 0.0003). Group I had a delayed time to eye opening (10.7 ± 1.72 min vs. 13.3 ± 2.35 min, p < 0.0001) and emergence stay (32.2 ± 5.62 min vs. 39.9 ± 6.7 min, p < 0.0001). There were no significant differences in POD and QoR-15 between the two groups on day three. IJV cannulation may not be the preferred approach in robot-assisted laparoscopic surgery as it was risk factor for IJVV regurgitation, ICP elevation, emergence delayed.

Sonographic Optic Nerve Sheath Diameter as a Guide for Correction of Hyponatremia in the Emergency Department: A Cross-sectional Study.

Monitoring sodium levels during the correction of hyponatremia is essential. There is cell swelling due to the movement of water from extracellular to intracellular by osmotic effect in hyponatremia. The cellular swelling in a closed space causes increased intracranial pressure (ICP). The raised ICP correlates with the optic nerve sheath diameter (ONSD). So, the research question was whether the ONSD can be used as a guide for the correction of hyponatremia. It was a prospective observational study conducted on patients with serum sodium below 135 mEq/L presented to the emergency department (ED). The ONSD was measured at the time of presentation and discharge of the patient. The receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to test the predictive ability of the ONSD to diagnose hyponatremia. A total of 54 subjects were included in the study. The mean sodium level was 109.3 mEq/L at presentation. The mean ONSD on the right side was 6.24 ± 0.71 mm and on the left side was 6.26 ± 0.64 mm at presentation to ED. The mean ONSD on the right side was 5.81 ± 0.58 mm and on the left side was 5.79 ± 0.56 mm at discharge. The ONSD was not able to predict the sodium level measured both by laboratory and POC methods. The ONSD failed to predict the sodium level in patients with hyponatremia during the correction. The change in ONSD did not correlate with the change in sodium level. Uttanganakam S, Hansda U, Sahoo S, Shaji IM, Guru S, Topno N, et al. Sonographic Optic Nerve Sheath Diameter as a Guide for Correction of Hyponatremia in the Emergency Department: A Cross-sectional Study. Indian J Crit Care Med 2023;27(4):265-269.

A Narrative Review of Point of Care Ultrasound Assessment of the Optic Nerve in Emergency Medicine

Point of care ultrasound (POCUS) of the optic nerve is easy to learn and has great diagnostic potential. Within emergency medicine, research has primarily focused on its use for the assessment of increased intracranial pressure, but many other applications exist, though the literature is heterogeneous and largely observational. This narrative review describes the principles of POCUS of the optic nerve including anatomy and scanning technique, as well as a summary of its best studied clinical applications of relevance in emergency medicine: increased intracranial pressure, idiopathic intracranial hypertension, optic neuritis, acute mountain sickness, and pediatric intracranial pressure assessment. In many of these applications, sonographic optic nerve sheath diameter (ONSD) has moderately high sensitivity and specificity, but the supporting studies are heterogeneous. Further studies should focus on standardization of the measurement of ONSD, establishment of consistent diagnostic thresholds for elevated intracranial pressure, and automation of ONSD measurement.

The Prediction of the Increase in intracranial Pressure in Stroke Patients Given Recombinant Tissue Plasminogen Activator by Measuring the optic Nerve Sheath Diameter on bedside Ultrasound.

Background: The aim of this study is based on the effects of the treatment, the recombinant tissue plasminogen activator (rTPA), applied to stroke patients in Emergency Departments (ED) by intravenous, to optic nerve sheath diameter (ONSD) measurements.&#x0D; Material and Methods: The study was designed as prospective and observational. A total of 41 patients were included in this study with the following diagnoses: an acute clinical stroke, known well-being within 4.5 hours, and who had a finding for rTPA. Ultrasonographic (USG) ONSD measurements have been performed on a voluntary basis with the consent of the patients and their relatives.&#x0D; Results: A statistically significant difference has been found between the ONSDs measured at the 0th, 15th, 30th and 60th minutes of the patients who were admitted to the ED and were on rTPA treatment due to stroke (p&lt;0.05). Due to a large number of positive differences, the ONSD at the 15th, 30th, and 60th minutes was found higher than at the 0th minute. A statistically significant difference has also been found between ONSD measured at the 15th, 30th, and 60th minutes during rTPA treatment (p&lt;0.05). Since the existence of a large number of positive differences, the ONSD at the 30th and 60th minutes is found to be higher than at the 15th minute. Finally, the difference of statistically significant values between the 30th and 60th-minute ONSD was determined by the Sign Test. According to the result of the Sign Test, a statistically significant difference was found to be between the ONSD differences of the 30th and 60th minutes of rTPA treatment (p&lt;0.05).&#x0D; Conclusions: Serial ONSD measurements performed at the bedside during the early stage in order to follow up on the intracranial complications of stroke patients may be misleading for the follow-up of complications within the first 60 minutes, which is the most critical stage. In this stage, symptom monitoring should be used in combination with ONSD and the decision should be made for treatment continues, accordingly.

The Role of Ultrasound in Pediatric Skull Fractures: Determination of Fracture and Optic Nerve Sheath Diameter Measurements.

The aim of the present study was to determine the accuracy of point-of-care ultrasound (POCUS) for detecting skull fractures and to evaluate sonographic measurements of optic nerve sheath diameter (ONSD) and ONSD/eyeball vertical diameter (EVD) ratios in children with head trauma. Children who presented with local signs of head trauma and underwent cranial computed tomography (CT) were enrolled. The suspected area was examined by POCUS to identify a skull fracture, and then the ONSD at 3 mm posterior to the globe and the EVD were measured. Ratios of ONSD measurement at 3 mm/EVD were reported. All ONSD measurements and ratios were calculated from cranial CT images. There were 112 children enrolled in the study. The sensitivity and specificity of POCUS for skull fractures was 93.7% (95% confidence interval [CI], 82.8-98.6) and 96.8% (95% CI, 89.1-99.6), whereas the positive predictive value was 95.7% (95% CI, 85.1-98.8), and the negative predictive value was 95.3% (95% CI, 87.3-98.4). There was high agreement between POCUS and CT for identifying skull fractures (κ, 0.90 [±0.04]). In the group without elevated intracranial pressure findings on CT, patients with space-occupying lesions (SOLs) had higher sonographic ONSD measurements and ratios (P < 0.001) compared with cases without SOLs. When used with clinical decision rules to minimize the risk for clinically important traumatic brain injury, POCUS seems to be a promising tool to detect skull fractures and calculate ONSD measurements and rates to predict the risk for SOLs and perform further risk stratification of children with minor head trauma.