Changes In Optic Nerve Sheath Diameter Research Articles

435 Use of Optic Nerve Sheath Diameter in Extraventricular Drain Weaning in Adults With Post-hemorrhagic Hydrocephalus

INTRODUCTION: Optic nerve sheath diameter (ONSD) can be used as a noninvasive measurement of intercranial pressure. Few studies have evaluated the value of ONSD in predicting the need for ventriculoperitoneal shunt (VPS) placement after development of post-hemorrhagic hydrocephalus (PHH) in adults. METHODS: Adult patients 18 years or older, admitted with intracranial hemorrhage and hydrocephalus requiring EVD placement were included in the study. Demographics were recorded. CT imaging of ONSD was measured (mm) upon initial ED visit before EVD placement (pre-EVD), immediately after successful EVD removal (post-EVD), and if applicable, after EVD removal but immediately before VPS placement. Change in ONSD was calculated and groups were stratified by EVD only patients and EVD+VPS patients. RESULTS: Imaging for 30 patients were successfully retrieved and analyzed for bilateral ONSD values at all timepoints. A statistically significant convergence to a normally distributed mean ONSD was found for both groups (EVD and EVD+VPS). Additionally, a statistically significant increase was found in ONSD between the EVD+VPS group compared to the EVD only group. The EVD only group showed a mean EVD placement time of only 14 days (2 weeks) with an average decrease in ONSD (-0.905mm) compared with the EVD+VPS group who had an increase in ONSD at 14-days (+1.089 mm). CONCLUSIONS: Patients with hydrocephalus due to intracranial hemorrhage who went on to require VPS developed an increase in ONSD despite EVD use while patients who were successfully weaned from the EVD developed a decrease in ONSD. ONSD may be a useful adjunct tool to aid in the process of EVD weaning in this patient population.

High myopia at high altitudes.

Background: Optic nerve sheath diameter (ONSD) increases significantly at high altitudes, and is associated with the presence and severity of acute mountain sickness (AMS). Exposure to hypobaria, hypoxia, and coldness when hiking also impacts intraocular pressure (IOP). To date, little is known about ocular physiological responses in trekkers with myopia at high altitudes. This study aimed to determine changes in the ONSD and IOP between participants with and without high myopia (HM) during hiking and to test whether these changes could predict symptoms of AMS. Methods: Nine participants with HM and 18 without HM participated in a 3-day trek of Xue Mountain. The ONSD, IOP, and questionnaires were examined before and during the trek of Xue Mountain. Results: The ONSD values increased significantly in both HM (p = 0.005) and non-HM trekkers (p = 0.018) at an altitude of 1,700m. In the HM group, IOP levels were greater than those in the non-HM group (p = 0.034) on the first day of trekking (altitude: 3,150m). No statistically significant difference was observed between the two groups for the values of ONSD. Fractional changes in ONSD at an altitude of 1,700m were related to the development of AMS (r pb = 0.448, p = 0.019) and the presence of headache symptoms (r pb = 0.542, p = 0.004). The area under the ROC curve for the diagnostic performance of ONSD fractional changes at an altitude of 1,700m was 0.859 for predicting the development of AMS and 0.803 for predicting the presence of headache symptoms. Conclusion: Analysis of changes in ONSD at moderate altitude could predict AMS symptoms before an ascent to high altitude. Myopia may impact physiological accommodation at high altitudes, and HM trekkers potentially demonstrate suboptimal regulation of aqueous humor in such environments.

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

Intracranial pressure increases in head-down tilt (HDT) body posture. This study evaluated the effect of HDT on the optic nerve sheath diameter (ONSD) in normal subjects. Twenty six healthy adults (age 28 [4.7] years) participated in seated and 6° HDT visits. For each visit, subjects presented at 11:00 h for baseline seated scans and then maintained a seated or 6° HDT posture from 12:00 to 15:00 h. Three horizontal axial and three vertical axial scans were obtained at 11:00, 12:00 and 15:00 h with a 10 MHz ultrasonography probe on the same eye, randomly chosen per subject. At each time point, horizontal and vertical ONSD (mm) were quantified by averaging three measures taken 3 mm behind the globe. In the seated visit, ONSDs were similar across time (p > 0.05), with an overall mean (standard deviation) of 4.71 (0.48) horizontally and 5.08 (0.44) vertically. ONSD was larger vertically than horizontally at each time point (p < 0.001). In the HDT visit, ONSD was significantly enlarged from baseline at 12:00 and 15:00 h (p < 0.001 horizontal and p < 0.05 vertical). Mean (standard error) horizontal ONSD change from baseline was 0.37 (0.07) HDT versus 0.10 (0.05) seated at 12:00 h (p = 0.002) and 0.41 (0.09) HDT versus 0.12 (0.06) seated at 15:00 h (p = 0.002); mean vertical ONSD change was 0.14 (0.07) HDT versus -0.07 (0.04) seated at 12:00 h (p = 0.02) and 0.19 (0.06) HDT versus -0.03 (0.04) seated at 15:00 h (p = 0.01). ONSD change in HDT was similar between 12:00 and 15:00 h (p ≥ 0.30). Changes at 12:00 h correlated with those at 15:00 h for horizontal (r = 0.78, p < 0.001) and vertical ONSD (r = 0.73, p < 0.001). The ONSD increased when body posture transitioned from seated to HDT position without any further change at the end of the 3 h in HDT.

The effect of restrictive vs. liberal fluid protocols on ocular parameters in patients undergoing prone spine surgery: a randomized controlled trial

BackgroundElevated intraocular pressure (IOP) and optic nerve edema occurring during prone surgeries may cause ocular and optic nerve ischaemia injury. We hypothesized that a liberal fluid protocol might further increase IOP and optic nerve sheath diameter (ONSD) than a restrictive fluid protocol for patients in the prone position.MethodsA single-centre, prospective and randomized trial was conducted. Patients were randomly allocated into 2 groups: the liberal fluid infusion group, in which repeated bolus doses of Ringer’s lactate solution were given to maintain pulse pressure variation (PPV) within 6~9%, and the restrictive fluid infusion group, where PPV was maintained within 13–16%. IOP and ONSD were measured in both eyes at 10min after the anaesthesia induction in the supine position, 10min after the prone position placement, and 1h and 2h since the prone position was placed, at the conclusion of surgery, and returned to the supine position.ResultsA total of 97 patients were recruited and completed the study. IOP increased significantly from 12±3mmHg in the supine position to 31±5 mmHg (p<0.001) at the end of surgery in the liberal fluid infusion group and from 12±2 to 28±4 mmHg (p<0.001) in the restrictive fluid infusion group. There was a statistically significant difference in the change of IOP over time between the two groups (p=0.019). ONSD increased significantly from 5.3±0.3mm in the supine position to 5.5±0.3mm (p<0.001) at the end of surgery in both groups (both p<0.001). There was no statistically significant difference in the change of ONSD over time between the two groups (p>0.05).ConclusionsCompared to the restrictive fluid protocol, the liberal fluid protocol increased IOP but not ONSD in patients undergoing prone spine surgery.Trial registrationThe study was registered in ClinicalTrials.gov (https://clinicaltrials.gov) prior to patient enrollment, ID: NCT03890510, on March 26, 2019. The principal investigator was Xiao-Yu Yang.

Evaluation of postictal optic nerve sheath diameter at epileptic patients

IntroductionDuring a seizure, metabolic rate and, consequently, cerebral blood flow increase to provide the required maintenance energy. It is thought that this causes an increase in intracranial pressure, but there is no comprehensive research on this subject. In this study, we aimed to measure and follow optic nerve sheath diameter (ONSD) in patients who applied to the emergency department (ED) after generalized tonic-clonic (GTC) seizures and to gain information about intracranial pressure changes in epilepsy patients in the postictal period. Materials and MethodsThis was a prospective observational study. Patients already diagnosed with epilepsy who applied to the ED within one hour after GTC seizures were included. The ONSD of the patients was measured by the same radiologist three times in both eyes using ultrasonography at the time of admission and the fourth hour of follow-up. The seizure characteristics and measurements of the patients were recorded, and the changes in ONSD over time and correlations between seizure characteristics and ONSD were examined. ResultsSixty-six patients were included in the study. Thirty-four (51.5%) of the patients had seizures with auras. For both eyes, the first-hour ONSD values of the patients [right: 5.90 (5.73–6.16) mm, left: 5.86 (5.73–6.13) mm] were significantly higher than the fourth-hour ONSD values [right: 5.26 (5.19–5.40) mm, left: 5.28 (5.16–5.36) mm)] (p < 0.001 for both eyes). Additionally, the first- and fourth-hour ONSD values of patients with seizures with auras were significantly higher than those with seizures without auras (p < 0.001 for each condition). There was no correlation between other variables related to seizure type and ONSD. ConclusionThis study showed that after GTC seizures in epilepsy patients, ONSD increases in the first hour postictal and decreases over time. Another important result is that the increase in ONSD values in seizures with auras is significantly higher than in seizures without auras.

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

To determine the normal values of optic nerve sheath diameter (ONSD) by computed tomography (CT) in the pediatric population. The CT scans of pediatric patients aged 1 to 16 years who underwent brain CT for different reasons, who did not have intracranial pathology or increased intracranial pressure, and who had no pathology on CT were included in the study. Four age groups were defined with the following ranges: 1 to 2, 3 to 6, 7 to 10, and 11 to 16 years. ONSD was measured from axial CT images, 3 and 10 mm behind the optic globe. The normative values of ONSD measured on CT imaging in children aged 1 to 16 years were reported. The change in ONSD according to age was investigated. ONSD was found to increase with age at both levels measured. The difference was statistically significant. Normal values should be known to detect pathologies that may cause an increase in optic nerve diameter. The values reported in this study can serve as a reference for normal optic nerve sheath diameter in the pediatric age group. [J Pediatr Ophthalmol Strabismus. 2024;61(1):38-43.].

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.

Effect of intravenous administration of 20% Mannitol on optic nerve sheath diameter in patients with raised intracranial pressure

Background and aims: Mannitol is commonly used to reduce elevated intracranial pressure (ICP) in patients with traumatic brain injury, intracranial hemorrhage and acute cerebrovascular accident. Optic nerve sheath diameter (ONSD) has high sensitivity and specificity in diagnosing raised ICP. This study aims to evaluate effect of Mannitol on ONSD in patients with raised ICP.&#x0D; Methods: This was a prospective cohort observational study of adult patients receiving osmotherapy for increased ICP admitted to the ICU. Baseline ONSD (T1) was recorded bilaterally followed by administration of Mannitol. ONSD was remeasured bilaterally at 30 (T2), 60 (T3) and 120 (T4) minutes after completion of administration of mannitol. Peak inspiratory pressures and PEEP were recorded for patients on mechanical ventilation.&#x0D; Results: Of the 40 patients included in the study, the mean age of patients was 54.03 ±19.15 years. Among them 26 were mechanically ventilated. Compared to the baseline values of 6.1 ± 0.74 mm, the mean ONSDs at T2, T3 and T4 were significantly lower after administration of 20% Mannitol with all p values &lt; 0.001. A statistically significant correlation between change in ONSD (ΔONSD) at each time point and the dose of Mannitol administered was observed.&#x0D; Conclusion: ONSD can be used for monitoring effectiveness of osmotherapy on a point-of-care basis in patients with elevated ICP.

The Association Between Hyponatremia and Optic Nerve Sheath Diameter: A Prospective Study.

Background Hyponatremia is a common electrolyte balance disorder. It may result in brain edema and increased intracranial pressure (ICP). Optic nerve sheath diameter (ONSD) measurement remains an increasingly sought-after method in many situations associated with ICP elevations. The aim of our study was to investigate the relationship between the change of ONSD before and after hypertonic saline (3% sodium chloride) treatment and the clinical improvement with increased sodium levels in patients with symptomatic hyponatremia who presented to the emergency department. Methodology This study was conducted in the emergency department of a tertiary hospital, according to the design of a prospective, self-controlled, non-randomized trial study. Determined by power analysis, 60 patients were included in the study. The statistical analysis of the continuous data was performed using the means, standard deviations, and minimum and maximum values of the feature values. The frequency and percentage values were used to define categorical variables. The mean difference comparison of pre-and post-treatment measurements was evaluated by paired t-test. P<0.05 was considered to be significant. Results The measurement parameters' differences before and after hypertonic saline treatment were evaluated. While the mean of the right eye ONSD was 5.27±0.22 mm before treatment, it declined substantially to 4.52±0.24 mm after treatment(p<0.001). It was also found that the left eye ONSD was 5.26±0.23 mm before the treatment and declined to 4.53±0.24 mm after the treatment (p<0.001). In addition, the mean of the overall ONSD was 5.26±0.23 mm before treatment and 4.52±0.24 mm after treatment (p<0.001). Conclusions Ultrasonic measurement of ONSD can be used to monitor the clinical improvement of patients receiving hypertonic saline therapy for symptomatic hyponatremia.

Optic nerve sheath diameter correlates to intracranial pressure in spontaneous CSF leak patients.

Spontaneous cerebrospinal fluid (sCSF) leaks develop from pressure erosion due to idiopathic intracranial hypertension, treatment of which is paramount to preventing recurrence. Direct measurements of intracranial pressure (ICP) for monitoring response to treatment via lumbar drain (LD) or ventriculostomy are invasive and have risks. The objectives of this study are to determine whether ultrasonographic measurements of optic nerve sheath diameter (ONSD) correlate with LD ICP in patients with sCSF leaks undergoing treatment, and whether ONSDs are larger in patients with sCSF leaks than controls. Subjects with sCSF leaks and controls were prospectively recruited. ONSD, sex, and body mass index (BMI) were analyzed. For sCSF leak subjects, ultrasonography was performed at the time of LD opening and each pressure check postoperatively, including the acetazolamide response. In control patients, measurements were obtained at the time of surgery. Pearson's correlation between ONSD and ICP was performed. Subjects with sCSF leaks (n=9, age 52.4±9.5, all female) and controls (n=8, age 60.1±14.8, two females) had significantly different BMIs, 38.4±8.1 vs. 29.2±4.8, t(15)=2.793, p=0.014. ONSD was strongly correlated with ICP measurements (r=0.583, p=0.002). However, percentage change in ONSD and ICP measurements were more strongly correlated (r=0.733, p<0.001). Patients with sCSF leaks had significantly higher ONSDs than controls, 0.63cm±0.044 vs. 0.56cm±0.074, t(15)=2.329, p=0.034. ONSD significantly correlated with ICP in sCSF leak patients and was wider in sCSF leak subjects than controls. Ultrasonography has utility in monitoring the ICP response to acetazolamide.

Analysis of dynamic changes in optic nerve sheath diameter (ONSD) with ultrasound in post-craniotomy patients: Trends and correlation with computed tomography ONSD and Glasgow coma scale in post-operative period.

Intracranial pressure (ICP) monitoring in patients with intracranial tumors undergoing craniotomy is usually done in perioperative period in intensive care unit. Invasive measurement of ICP, though considered as the gold standard, has its own limitations such as availability of expertise, equipment, and associated complications. Period of raised ICP in post-operative period may impact patient outcomes. Post-craniotomy computed tomography (CT) assessment is done routinely and may need to be repeated if indicated during post-operative stay. Utility of sonographic serial optic nerve sheath diameter (ONSD) assessment in post-operative monitoring of patients who have undergone elective craniotomy was explored in this study. The primary objective of the study was to measure the dynamic change in ONSD as compared to baseline pre-operative measurement in the first 3 postoperative days after elective craniotomy. The secondary objective of the study was to evaluate correlation between ONSD value with Glasgow Coma Scale (GCS) and post-operative CT findings. In this prospective, observational, and cohort study, we studied adult patients undergoing craniotomy for intracranial tumors. GCS assessment and sonographic measurement of ONSD were done preoperatively, immediate post-operative period, and 12, 24, and 48 h after surgery. CT scan to detect raised ICP was done at 24 h post-operative. Correlation of ONSD with GCS at respective period and correlation of CT scan finding with respective ONSD assessment were evaluated. A total of 57 patients underwent elective craniotomy for intracranial tumors. Significant difference was observed in ONSD value depending on time of measurement perioperatively (χ2 = 78.9, P = 0.00). There was initial increase in the first 12 h followed by decrease in ONSD in the next 48 h. Negative correlation was observed between baseline ONSD and 12 h GCS (ρ = -0.345, P = 0.013). There was significant change in GCS scores based on the status of ONSD (raised or normal) at 12 h after surgery (P = 0.014). Significant correlation between USG ONSD and CT ONSD was observed (ρ = 0.928, P = 0.000). Optimal cutoff value of ONSD to detect raised ICP with reference to CT signs was 4.8 mm with 80% sensitivity and 95% specificity. ONSD undergoes dynamic changes, correlates with CT scan, and has good diagnostic accuracy to detect raised ICP post-craniotomy for intracranial tumors. It may serve as a useful tool in monitoring in resource-limited setup.

Optic nerve sheath diameter changes at altitude

AbstractPurpose: This study aimed to assess variations in Optic Nerve Sheath Diameter (ONSD) as a correlate of Intracranial Pressure (ICP) during ascent to high‐altitude and to explore the relationship between ONSD and Acute Mountain Sickness (AMS). AMS is a high‐altitude illness characterized by headaches, lethargy, nausea and vomiting. At present there is no consensus on the pathophysiology of AMS. There are similarities in symptomology between AMS and raised ICP. A greater understanding of ICP at altitude and its role in AMS may yield new strategies for management of the illness.Methods: We conducted a longitudinal cohort study involving 10 mountaineers climbing Mt Toubkal (4167 m). Participants underwent daily binocular ultrasound B‐scans at interval altitudes during the ascent. Altitude, AMS diagnosis and severity (using Lake Louise Score [LLS]) were recorded concurrently with ultrasound examinations. Ultrasound scans were reviewed by a blinded observer who measured ONSD and assessed image quality (1 = poor, 2 = moderate, 3 = good).Results: During the ascent to 4167 m and return to low‐land, there was no significant variation in left (p = 0.97), right (p = 0.68) or mean (p = 0.86) ONSD. The ratio of ONSD to baseline was significantly (p = 0.038) greater in participants with AMS on Day 5; this was not consistent across all time points. No significant correlation between the ratio of ONSD to baseline and LLS was observed at any time point. Mean image quality was 2.12 (SD ± 0.65); images largely scored in the ‘Moderate’ – ‘Good’ range.Conclusions: This study is reflective of changes in ONSD during slow ascent profiles commonly used in mountaineering. This suggests that ONSD and therefore ICP does not significantly vary during this style of ascent to 4167 m. We did not identify any convincing relationship between AMS and ONSD, adding to previous research suggesting the same. Considering the limitations of this study, it cannot stand alone to disapprove a causal relationship between ONSD and AMS.

Optic Nerve Sheath Diameter Affected by Cervical Collar Placement in Minor Head Trauma Patients

Background: Head trauma may cause an increase in intracranial pressure (ICP). The use of ocular ultrasound to measure optic nerve sheath diameter (ONSD) is a method to determine the ICP. The use of the rigid cervical collar in head trauma patients contribute to elevating ICP, and therefore, potentially causing further deterioration in their condition. Objectives: This study aimed to describe changes in ONSD after the placement of a c-collar and analyze these changes depending on the time in the c-collar. Methods: This prospective study measured the ONSD of minor head trauma patients before and after the placement of a c-collar. Patients aged ³18 with blunt head trauma and Glasgow Coma Score ³13 were included in the study. Each eye was scanned twice. This was done before c-collar placement, at 5 and 20 min after placement. The mean values of both eyes were calculated and analyzed. Results: This study investigated 50 patients. The mean baseline ONSD was obtained at 4.71mm±0.22 (4.54-4.77). Furthermore, T5 and T20 measurements were 5.19±0.41 (5.07-5.31) and 5.26±0.45 (5.14-5.39), respectively. The ONSD increased at T5 and T20. The changes from the baseline measurements were statistically significant (P=0.000, P=0.000). The difference between T5 and T20 groups was an increase in ONSD, and these differences were also statistically significant (0.07±0.19; P=0.008). Conclusion: Our results revealed that minor head trauma patients using a c-collar may increase ONSD by timeline the clinical effects of which have to be determined with further studies. Enlargement in ONSD should be considered when interpreting ICP.

Abstract 204: Optic Nerve Sheath Diameter Trajectories During Targeted Temperature Management

Introduction: The extent of hypoxic-ischemic injury (HII) after cardiac arrest (CA) remains an important knowledge deficit with lack of objective clinical data that is measurable repeatedly. There is a need to better understand an individual patient’s level of HII. Optic nerve sheath diameter (ONSD) has not been explored after CA as a possible bedside modality to measure the extent of HII over time, at the bedside, during targeted temperature management (TTM). Objective: We sought to characterize the temporal trajectories of point-of-care ultrasound obtained ONSD during the post- return of spontaneous circulation (ROSC) phase, in patients with and without TTM. Methods: Adult CA patients at an urban academic ED were included from 2017-2021. ONSD was measured by emergency ultrasound fellowship trained faculty at 1, 6, 24, 48, and 72 hours after ROSC using an ocular preset on a 15MHz linear probe. ONSD measurements at these time points were compared with patient demographic information and intervention of TTM . Results: A total of 78 participants had ONSD measurements. The mean age was 62 (+/-15) and 46% were female. Of the 65% of the cases with TTM, a sex disparity was noted with 73% of males receiving TTM versus 56% of females. There was a trend toward a decrease in mean ONSD by 0.015cm for TTM patients during the early time points of 1 to 6 hours compared to an increase in 0.006cm in those without TTM. Similar trend was noted between 1 to 24 hours, with a decrease in ONSD by 0.025cm in those with TTM relative to an average increase of 0.008 cm in those without TTM. However, neither delta ONSD was statistically significant between the two cohorts. When further assessing if delay in cooling had an impact on ONSD change, we found that the ONSD change between 24 to 48 hours was significantly increased in those in whom TTM was not initiated within 14 hours (beta=0.036; p=0.016). Conclusion: This pilot study revealed ONSD changes during TTM. There is potential for monitoring brain injury through ONSD trajectories to evaluate responders vs non-responders to TTM. Additional research is needed to evaluate ONSD changes during the rewarming time frame and may further distinguish patients with worse HII. Correlation to survival outcomes can be possible with a larger sample size.

Evaluation of the Effect of Interscalene Brachial Plexus Block on Intracranial Pressure Using Optic Nerve Sheath Diameter and Internal Jugular vein Collapsibility Index.

To determine the effect of single-shot interscalene brachial plexus (ISBP) block on intracranial pressure (ICP) by evaluating the extravascular volume effect of the medicine on the internal jugular vein (IJV). Interventional study. Department of Anaesthesiology and Reanimation, Sivas Cumhuriyet University, Sivas, Turkey, from January to June 2022. Thirty-four patients were included in this prospective clinical study. All patients had single-shot ISBP block with 25 ml of local anaesthetic. Optic nerve sheath diameter (ONSD), maximum (Dmax) and minimum (Dmin) diameters of IJV and IJV collapsibility index (IJV-CI) were recorded before the block (basal), 20 minutes, and 60 minutes after the block. Twenty-nine patients had higher ONSD values at 60th minute compared to their basal values. There were negative correlations between the changes of ONSD and IJVCI (r=0.616, p<0.001) and ONSD and Dmax (r=0.581, p<0.001) in time period between basal and 20th minute. There were negative correlations between the changes of ONSD and IJVCI (r=0.518, p=0.002), ONSD and Dmax (r=0.664, p<0.001) in time period between basal and 60th minute. Single-shot ISBP block with 25 ml of local anaesthetic may be a factor that increases ICP. Repeated intraoperative ONSD measurements are recommended in patients operated with ISBP block. Interscalene Brachial Plexus Block, Intracranial pressure, Optic nerve sheath diameter, Internal jugular vein collapsibility index.

The Effect of Fluid Challenge Test on Optic Nerve Sheath Diameter.

To investigate the effect of the fluid challenge test on the optic nerve sheath diameter (ONSD) change. Quasi-experimental study. Department of Anesthesiology and Reanimation, Ondokuz Mayis University Hospital, Samsun, Turkey, from January to November 2021. A fluid challenge was defined as a 500 mL crystalloid infusion administered over 10 minutes, and fluid responsiveness was defined as a subsequent increase in stroke volume of at least 15% administered to the ICU patients. The ONSD and hemodynamic variables were measured by ultrasonography before (T0), at the end (T1), and 30 min after the fluid challenge (T2). The primary outcome of the study was the change in ONSD measurements associated with the fluid challenge, and the secondary outcome was the relationship between fluid responsiveness and the change in ONSD. A total of 60 patients were included. The ONSD (mm) value was significantly higher at T1 compared to T0 (mean ± standard deviation: 5.12±0.30 mm vs. 5.10±0.32 mm; p=0.011). However, at T2, the ONSD was similar to that at T0 (5.10±0.31 mm vs. 5.10±0.32 mm; p=0.662). The stroke volume (mL) was also significantly higher at T1 and T2 compared to T0 [median IQR 60 (6) mL vs. 60 (4.7) mL vs. 52 (5) mL, respectively, p <0.01]. No significant relationship was found between the ONSD and the change in fluid responsiveness (p=0.621). The fluid challenge test increases ONSD and may cause an increase in intracranial pressure. Fluid therapy, Stroke volume, Intracranial pressure, Ultrasonography, Optic nerve sheath diameter.

Retrospective Evaluation of Optic Nerve Sheath Diameters of Patients Diagnosed With Brain Death

Introduction: Aim of the study is to investigate whether there is a correlation between causes of brain death, blood gas parameters before and after the apnea test and optic nerve sheath diameter (ONSD).&#x0D; Method: The records of 92 patients with brain death diagnosis were retrospectively analyzed for ONSD measurements of the right and left eyes, partial carbon dioxide pressure (pCO2), blood gas parameters before and after the apnea test. &#x0D; Results: Subarachnoidal hemorrhage and intracerebral hemorrhage were the two most common brain death etiology. Mean ONSD for right eye was 6.37±1.03 mm. Mean ONSD for left eye was 6.43±1.02 mm. Only 8 patients had ONSD below 5.00 mm. There was no statistically significant correlation between the percent change of pCO2 and ONSD change (p&gt;0.05).&#x0D; Conclusion: The present study shows that ONSD values are very high regardless of the partial pressure of carbon dioxide in patients with brain death diagnosis. We can suggest that ONSD can find itself a place for evaluating comatose patients for brain death diagnosis.

Investigation of intracranial pressure in intensive care unit patients with delirium assessed by bedside ultrasound

To explore the changes of intracranial pressure in intensive care unit (ICU) patients during the occurrence and evolution of delirium by using bedside ultrasound to measure the optic nerve sheath diameter (ONSD) to evaluate intracranial pressure. A retrospective observational study was conducted. Adult patients who developed delirium during hospitalization in the general ICU of Beihai People's Hospital from October 2020 to November 2021 were enrolled, and patients who did not have ultrasonographic ONSD records within 24 hours after the diagnosis of delirium were excluded. The ONSD measured before delirium was recorded as ONSD0, the ONSD measured within 24 hours of the onset of delirium recorded as ONSD1, and the ONSD reexamined after ONSD1 recorded as ONSD2. Patients were divided into intracranial hypertension group (ONSD1 > 5 mm) and normal intracranial pressure group (ONSD1 ≤ 5 mm) according to the size of ONSD1. According to the outcome of delirium, the patients were divided into cured, improved, and non-improved groups. The reduction ratio of ONSD2 to ONSD1 in the three groups were calculated and compared. Pearson correlation test was used to analyze the correlation between fluid balance and ONSD changes after delirium. There were 43 patients, including 40 cases in the intracranial hypertension group (the incidence rate was 93.0%), 3 cases in the normal intracranial pressure group, 23 cases were cured, 13 cases were improved, and 7 cases were not improved. In the intracranial hypertension group, 11 cases had ONSD0 and ONSD1 records, and ONSD1 was significantly higher than ONSD0 [mm: 5.88±0.61 vs. 5.34±0.57, 95% confidence interval (95%CI) -0.85 to -0.23, P = 0.003]. The reduction ratio of ONSD2 to ONSD1 in the cured group was significantly higher than that in the improved group and the non-improved group [(12.04±6.20)% vs. (5.68±4.10)%, (0.17±3.96)%; 95%CI were 2.37 to 10.33, 6.41 to 17.31, P values were 0.003 and 0.000, respectively]. The correlation analysis showed that the reduction ratio of ONSD2 to ONSD1 was negatively correlated with fluid balance (r = -0.42, 95%CI was -0.66 to -0.10, P = 0.012). The incidence of intracranial hypertension in ICU delirium patients is high. A more pronounced decrease in intracranial pressure predicts a better delirium outcome. Dynamic ONSD measurement can provide valuable information for the prevention and treatment of delirium.

Can optic nerve sheath diameter assessment be used as a non-invasive tool to dynamically monitor intracranial pressure?

This study aims to detect whether the optic nerve sheath diameter (ONSD) can be used to dynamically monitor intracranial pressure (ICP). Adult patients undergoing invasive ICP monitoring on the day of admission are included in this study. For each patient, the ONSD is first measured in the supine position and then in the 30° head-up position. Subsequently, a dynamic test is conducted on 16 patients. The ONSD is measured in the supine position once a day for three consecutive days starting on the day of admission. There is a strong correlation between the ONSD and ICP values in the supine position on admission (r = 0.799), and when patients are changed from the supine to the 30° head-up position, the ICP and ONSD values decrease correspondingly. However, the change in ICP is not strongly correlated with the change in ONSD (r = 0.358). In the dynamic test, a good agreement between the ICP and ONSD only exists in three patients (18.8%), and three patients have completely different profiles for ICP and ONSD. These results suggest that the changes in the ONSD and ICP values are not closely correlated after dynamic observation. Therefore, measurement of the ONSD may not be a suitable tool to dynamically monitor ICP.

Evaluation of intra-cranial pressure changes by measuring the optic nerve sheath diameter during the lung recruitment maneuver in patients with acute respiratory distress syndrome: A prospective study.

The lung recruitment maneuver (LRM) applied in acute respiratory distress syndrome (ARDS) may increase the intra-cranial pressure (ICP). This study evaluated the effect of LRM on intra-cranial pressure changes in patients with ARDS by measuring the optic nerve sheath diameter (ONSD). LRM was applied to patients undergoing follow-up for ARDS, with a positive pressure of 30 cmH2O for 30 s. ONSD on ultra-sonography, dynamic lung compliance (Cdyn), oxygen saturation (SpO2), and hemodynamic parameters were measured before (T0), immediately after (T1), and 10 min after (T2) LRM. The primary endpoint was the effect of LRM on ONSD changes. The secondary endpoints included the effect of LRM on Cdyn, SpO2 change, and relationship between Cdyn and ONSD changes. The study included 60 patients. ONSD was higher at T1 than at T0 (median [interquartile range]: 5.13 [0.4] vs. 5.3 [0.3] mm, P < 0.001) but was similar at T0 and T2 (5.13 [0.4] vs. 5.09 [0.37] mm, P = 0.36). Cdyn and SpO2 were significantly higher at T1 and T2 than at T0 (Cdyn: 22.3 [5.8] vs. 23.7 [7.5] vs. 19.4 [6.6] mL/cmH2O, P < 0.001; SpO2: 90[2] vs. 92[4] vs. 88[4] %, P = 0.013). A significant correlation existed between Cdyn and ONSD changes, which increased at T2 compared to T0 (P < 0.001). LRM applied in ARDS causes a short-term increase in ONSD. However, Cdyn increases 10 min after LRM and causes ONSD, thereby leading to a decrease in ICP.