Optic Nerve Sheath Diameter In Patients Research Articles

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

We aimed to describe the neurosonological findings related to cerebral hemodynamics acquired using transcranial Doppler and to determine the frequency of elevated ICP by optic nerve sheath diameter (ONSD) measurement in patients with severe coronavirus disease (COVID-19) hospitalized in the intensive care unit of a national referral hospital in Peru. We included a retrospective cohort of adult patients hospitalized with severe COVID-19 and acute respiratory failure within the first 7 days of mechanical ventilation under deep sedoanalgesia, with or without neuromuscular blockade who underwent ocular ultrasound and transcranial Doppler. We determine the frequency of elevated ICP by measuring the diameter of the optic nerve sheath, choosing as best cut-off value a diameter equal to or >5.8 mm. We also determine the frequency of sonographic patterns obtained by transcranial Doppler. Through insonation of the middle cerebral artery. Likewise, we evaluated the associations of clinical, mechanical ventilator, and arterial blood gas variables with ONSD ≥5.8 mm and pulsatility index (PI) ≥1.1. We also evaluated the associations of hemodynamic findings and ONSD with mortality the effect size was estimated using Poisson regression models with robust variance. This study included 142 patients. The mean age was 51.39 ± 13.3 years, and 78.9% of patients were male. Vasopressors were used in 45.1% of patients, and mean arterial pressure was 81.87 ± 10.64 mmHg. The mean partial pressure of carbon dioxide (PaCO2) was elevated (54.08 ± 16.01 mmHg). Elevated intracranial pressure was seen in 83.1% of patients, as estimated based on ONSD ≥5.8 mm. A mortality rate of 16.2% was reported. In the multivariate analysis, age was associated with elevated ONSD (risk ratio [RR] = 1.07). PaCO2 was a protective factor (RR = 0.64) in the cases of PI ≥ 1.1. In the mortality analysis, the mean velocity was a risk factor for mortality (RR = 1.15). A high rate of intracranial hypertension was reported, with ONSD measurement being the most reliable method for estimation. The increase in ICP measured by ONSD in patients with severe COVID-19 on mechanical ventilation is not associated to hypercapnia or elevated intrathoracic pressures derived from protective mechanical ventilation.

Optic nerve sheath diameter measured by ultrasonography versus Magnetic Resonance Imaging for diagnosing increased intracranial pressure: a systematic review and meta-analysis.

To compare the accuracy of the optic nerve sheath diameter (ONSD) measured by ocular ultrasonography (US) versus magnetic resonance imaging (MRI) for the diagnosis of increased intracranial pressure (ICP). A systematic search of studies evaluating US ONSD or MRI ONSD for the diagnosis of increased ICP was performed. Data were extracted independently by two authors. We used the bivariate random-effects model to evaluate the diagnostic feasibility of measuring the ONSD in patients increased ICP. A summary receiver operating characteristic (SROC) graph was adopted to calculate sensitivity and specificity. Subgroup analysis was used to explore potential difference in US ONSD and MRI ONSD. A total of 31 studies were included, in which there were 1783 patients diagnosed with US ONSD and 730 patients diagnosed with MRI ONSD. Twenty studies reporting US ONSD were included for quantitative synthesis. The US ONSD had a high diagnostic accuracy, involving estimated sensitivity of 0.92 (95%CI 0.87-0.95), estimated specificity of 0.85 (95%CI 0.79-0.89), positive likelihood ratio (PLR) of 6.0 (95%CI 4.3-8.4), negative likelihood ratio (NLR) of 0.10 (95%CI 0.06-0.15) and Diagnostic Odds Ratio (DOR) of 62 (95%CI 33-117). The data of 11 studies adopting MRI ONSD was pooled. The MRI ONSD demonstrated estimated sensitivity of 0.70 (95%CI 0.60-0.78), estimated specificity of 0.85 (95%CI 0.80-0.90), PLR of 4.8 (95%CI 3.4-6.7), NLR of 0.35 (95%CI 0.27-0.47) and DOR of 13 (95%CI 8-22). The subgroup analysis showed that US ONSD demonstrated a higher sensitivity (0.92 versus 0.70; p<0.01) and almost equal specificity (0.85 vs. 0.85; p=0.67) compared with MRI ONSD. Measurement of ONSD can be a useful tool to predict raised ICP. The US ONSD demonstrated better accuracy than MRI ONSD for the diagnosis of increased ICP.

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.

Comparative study between ultrasound guided coronal versus axial optic nerve sheath diameter measurement in patients at risk of increased intracranial pressure

Background: This work intended to contrast the effectiveness as well as precision of ultrasound guided coronal versus axial optic nerve sheath diameter (ONSD) measurement in patients at danger of elevated intracranial pressure (ICP). The optic nerve is a tubular structure of approximately 5 cm in Length, in which its intraorbital segment is evaluable sonographically. Methods: The 70 patients in this prospective, randomised, double-blinded trial spanned in age from 18 to 60 and had moderately to grave traumatic brain injury (TBI) when they were transferred to the intensive care unit (ICU) with a GCS of 3-12. There were two groups of patients: Patients in Group A do not exhibit elevated ICP readings on brain CT scans. Group B: Patients who had elevated ICP found on a brain CT scan. Results: There were non-significant higher mean coronal ONSD in comparison to mean axial ONSD in both groups. significant higher mean ONSD and mean axial and coronal ONSD in patients of group B. The Glasgow Coma Scale (GCS) was considerably lower in group B patients. In addition, there was a substantial inverse correlation between the mean ONSD, mean coronal and axial ONSD (mm), and the GCS for patients in both categories. Conclusions: In patients with trauma to the brain, monitoring the diameter of the optic nerve sheath with bedside ocular ultrasonography is a beneficial non-invasive way to detect excessive intracranial pressure earlier and correlation via the two methods (axial and coronal) gives us more accurate measurements.

Optic nerve sheath diameter and axial length in patients with optic disc drusen: a cross-sectional study

Measuring the optic nerve sheath diameter (ONSD) and the anteroposterior axial length of the eye in patients with optic disc drusen (ODD). A total of 43 healthy volunteers and41patients with ODD were included in the study.The ONSD and axial length were measured in theposterior positionusing an ultrasound device (E-Z Scan AB5500 +)probe with a 10MHz frequency. The ONSD was measured 3mm behind the globe wall.Receiver operating characteristic (ROC) curve analysis was performed to determine patients with ODD using ONSD.Any p-value of < 0.05 was accepted to demonstrate significance. The ONSD was significantly higher(5.2mm and 4.8mm, p = 0.006,respectively),andthe axial length was shorter(21.82 ± 2.15mmand23.27 ± 1.96mm,p = 0.002,respectively) in the ODD group.The spherical equivalent was more commonly seen as hypermetropic in the ODD group (1.00 [- 0.85 to 1.75]).In the ROCanalysisto determine the ONSD value in ODD diagnosis, the area under the curvewas 0.6754 (95% confidence interval 0.559-0.788, p = 0.006).ONSD cutoff of 5.70mm had a sensitivity of 0.366 and a specificity of 0.907 to diagnose ODD. In this study, the ONSD was significantly higher in the ODD group. The axial length was shorter in the ODD group.This study is the first in the literature to evaluate the ONSD in patients with optic disc drusen.Further studies are needed in this regard.

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 Clinical Importance of Optic Nerve Sheath Diameter in Patients with Traumatic Brain Injury: Preliminary Report

Traumatic brain injury (TBI) is a serious health problem that is related to an increased mortality. In cases of severe TBI, the prediction of prognosis is essential. The enlargement of the optic nerve sheath diameter (ONSD) shows an increased intracranial pressure and is associated with poor outcomes. In this study, we aimed to evaluate the prognostic value of ONSD in patients with severe TBI. Forty-four patients with severe TBI were retrospectively enrolled in the study. The patients were divided into two groups: survivors (n=17) and non-survivors (n=27). Baseline characteristics, clinical data, Glasgow coma scale (GCS) on hospital admission, brain computed tomography (CT) results, injury severity score (ISS), and Marshall score were recorded for all patients. ONSD was calculated at 3 mm distance from the globe, immediately below the sclera. The ONSD on the initial CT was significantly higher in non-survivors compared with survivors (6.83±1.40 vs. 6.40±1.36, p<0.05). In addition, ISS and Marshall score were significantly higher, whereas GCS was significantly lower in non-survivors. ONSD was positively correlated with Marshall score (r=0.332, p<0.05). Receiver operating characteristics analysis demonstrated that ONSD ≥6.61 had a sensitivity of 70.4% and specificity of 64.7% for predicting mortality. It was shown that ONSD ≥6.61 had a 4.3-fold increased risk for in-hospital mortality (odds ratio: 4.35; 95% confidence interval: 1.195-15.865; p<0.05). The enlargement of ONSD on initial CT was detected to be associated with increased in-hospital mortality in patients with severe TBI.

Measuring optic nerve sheath diameter using ultrasonography in patients with idiopathic intracranial hypertension.

Idiopathic intracranial hypertension (IIH) is primarily a disorder of obese young women characterized by symptoms associated with raised intracranial pressure in the absence of a space-occupying lesion. To compare the mean optic nerve sheath diameter (ONSD) measured using ultrasonography (USG) in patients with idiopathic intracranial hypertension (IIH) and normal healthy individuals. A prospective study. Ninety-seven participants aged 18-80 years were divided into two groups as patients with IIH (n=47) and the control group (n=50). The ONSD was measured using ultrasound with a 10-MHz probe. ONSD was measured 3 mm behind the optic disc. Receiver operating characteristic (ROC) curve analysis was performed to determine patients with IIH using ONSD. Body mass index was higher in the IIH group compared with the control group (p=0.001). The mean ONSD was statistically significantly thicker in the IIH group (6.4 mm) than in the control group (4.90 mm). The cut-off value of ONSD in patients with IIH was measured as 5.70 mm. There was a significant negative correlation between ONSD and age (r:-0.416 and p<0.001). There was a positive correlation between BMI and ONSD (r: 0.437 and p<0.001). Ultrasound can be a reliable, non-invasive and rapid tool to measure ONSD in monitoring patients with IIH. After the first diagnosis of IIH, based on neuroimaging and measuring intracranial pressure using invasive methods, ONSD can be used in treatment and follow-up.

Effect of Orogastric Acetazolamide on Optic Nerve Sheath Diameter in Patients Undergoing Laparoscopic Donor Nephrectomies: A Randomized, Double-Blind Trial.

IntroductionLaparoscopic Live Donor Nephrectomy(LLDN) is becoming an increasingly frequent procedure. The rise in intracranial pressure(ICP) during LLDN has not been measured yet. ICP can be evaluated by measuring ultrasonographic optic nerve sheath diameter(ONSD). Acetazolamide has been found to provide effective analgesia following LLDN. It also helps lowering the raised ICP. Therefore, we planned to study effect of orogastric Acetazolamide on ONSD in patients undergoing LLDN.MethodsForty Donors scheduled for LLDN were randomized preoperatively either into Group A receiving acetazolamide 5mg/kg or Group S receiving normal saline. ONSD was measured at time points:Time 0: In supine position before induction of GA, Time 1: 5 minutes after induction of GA but before giving orogastric acetazolamide, Time 2: 10 minutes after creating pneumoperitoneum, Time 3: 60 minutes after creating pneumoperitoneum, Time 4: Towards end of surgery, just before taking out specimen in modified flank position, Time 5: after extubating in supine position.ResultsMean ONSD of left eye(4.42 ± 0.48) in Group S was significantly more than mean ONSD of left eye(4.16 ± 0.15; p-0.036) in Group A at 10 mins after creating pneumoperitoneum in modified flank position. Mean ONSD showed significant increase in group S at 10 and 60 minutes(4.374 ± 0.433mm in group S vs 4.151 ± 0.168 in group A; p-0.042 at 10 mins and 4.336 ± 0.301mm in group S vs 4.149 ± 0.282mm in group A; p-0.050 at 60 mins) after creating pneumoperitoneum as compared to group A.ConclusionOrogastric acetazolamide 5 mg/kg was found to be beneficial in preventing rise in ONSD from 10 minutes to 1 hour of creating pneumoperitoneum in patients undergoing laparoscopic donor nephrectomy under general anaesthesia. Acetazolamide was also found to be effective in reducing postoperative pain.

Optic nerve sheath diameter and its implications in the evaluation of cerebral venous sinus thrombosis.

PurposeTo ascertain the role of optic nerve sheath diameter (ONSD) in the evaluation of cerebral venous sinus thrombosis (CVST).Material and methodsA retrospective study with convenient sampling was done during the period November 2018 to January 2020. Forty-one patients across all age groups with magnetic resonance venography (MRV) diagnosis of CVST and 82 gender-matched controls were included in the study. ONSD was measured on axial T2-weighted magnetic resonance images. CVST was identified on axial TOF-MRV including the stage, degree, and location. Intraparenchymal infarction and haemorrhage were also noted with their stage and size. The distribution of values for ONSD was tested for equality of variances using independent samples t-test. A cut-off value for ONSD was derived using ROC analysis.ResultsThe mean difference between ONSD of cases and controls was 0.84 mm (95% CI: 0.61-1.06) and was statistically significant at p < 0.001. Mean ONSD in cases was 5.33 ± 0.66, and in the control group it was 4.49 ± 0.31. The cut-off value for ONSD was taken as 4.57 mm, derived using the ROC analysis (AUC was 0.876 suggesting good diagnostic accuracy). ONSD showed a sensitivity of 87% and a negative predictive value of 89% in predicting CVST. However, we found no statistical significance between ONSD in patients with acute or chronic thrombosis or in those with neuroparenchymal complications.ConclusionsONSD is a valid triage tool with high sensitivity and negative predictive value, and it can be used in the evaluation of CVST.

The clinical and prognostic values of optic nerve sheath diameter and optic nerve sheath diameter/eyeball transverse diameter ratio in comatose patients with supratentorial lesions

BackgroundThe optic nerve sheath diameter (ONSD) and ONSD/eyeball transverse diameter (ETD) ratio have been proven to be correlated with intracranial pressure. This study aimed to evaluate the prognostic roles of ONSD and the ONSD/ETD ratio in comatose patients with supratentorial lesions and to determine the relationship of these two indices with the prognosis of such patients.MethodsA total of 54 comatose patients with supratentorial lesions and 50 healthy controls were retrospectively included in this study. ONSD and ETD were measured by unenhanced computed tomography (CT). The differences in ONSD and the ONSD/ETD ratio between the two groups were compared. The prognosis of comatose patients was scored using the Glasgow Outcome Scale (GOS) at the 3-month follow-up, and these patients were classified into good (GOS score ≥ 3) and poor (GOS score < 3) prognosis groups. The differences in ONSD and the ONSD/ETD ratio were compared between comatose patients with good prognoses and those with poor prognoses.ResultsThe ONSD and ONSD/ETD ratios in the comatose patients were 6.30 ± 0.60 mm and 0.27 ± 0.03, respectively, and both were significantly greater than those in the healthy controls (5.10 ± 0.47 mm, t = 11.426, P < 0.0001; 0.22 ± 0.02, t = 11.468, P < 0.0001; respectively). ONSD in patients with poor prognosis was significantly greater than that in patients with good prognosis (6.40 ± 0.56 vs. 6.03 ± 0.61 mm, t = 2.197, P = 0.032). The ONSD/ETD ratio in patients with poor prognosis was significantly greater than that in patients with good prognosis (0.28 ± 0.02 vs. 0.26 ± 0.03, t = 2.622, P = 0.011). The area under the receiver operating characteristic (ROC) curve, used to predict the prognosis of comatose patients, was 0.650 (95% confidence interval (CI): 0.486–0.815, P = 0.078) for ONSD and 0.711 (95% CI: 0.548–0.874, P = 0.014) for the ONSD/ETD ratio.ConclusionsThe ONSD and ONSD/ETD ratios were elevated in comatose patients. The ONSD/ETD ratio might be more valuable than ONSD in predicting the prognoses of comatose patients with supratentorial lesions.

Reverse Trendelenburg position applied prior to pneumoperitoneum prevents excessive increase in optic nerve sheath diameter in laparoscopic cholecystectomy: randomized controlled trial.

The aim of this randomized controlled trial was to determine whether applying the reverse Trendelenburg position before pneumoperitoneum has a preventive effect on increased intracranial pressure using optic nerve sheath diameter (ONSD) measurement as a noninvasive parameter. Seventy-nine patients were allocated to two groups according to whether pneumoperitoneum was applied in the supine position (group S, n = 40) or in the reverse Trendelenburg position (group RT, n = 39). The ONSD was measured at the following time points: T0: before anesthesia; T1: after endotracheal intubation; T2: after pneumoperitoneum in group S and after positioning in group RT; T3: after positioning in group S and after pneumoperitoneum in group RT; T4: 30min after endotracheal intubation, and T5: after desufflation. The end-tidal carbon dioxide (EtCO2), regional cerebral oxygen saturation (rSO2), peripheral oxygen saturation (SpO2), mean arterial pressure (MAP), heart rate (HR), peak inspiratory pressure (Ppeak), and dynamic compliance (Cdyn) were recorded. Background and perioperative characteristics were similar in both groups. In group S, the ONSD was higher at T2, T3, T4, and T5 than that in group RT (p < 0.001, p = 0.002, p = 0.001, and p = 0.012, respectively). In the same group, the number of patients with an ONSD above 5.8mm was higher at T2, T3, and T4 (p < 0.001, p = 0.042, p = 0.036, respectively). The rSO2 and SpO2 were not different between the groups. The mean arterial pressure was lower in group RT at T2, and the HR was not different between the groups (p < 0.001). In group S, Ppeak was higher and Cdyn was lower at T2 (p < 0.001). The number of patients with nausea was higher in group S (p = 0.027). The present study demonstrates that applying the reverse Trendelenburg position before pneumoperitoneum prevented an increase in the ONSD in patients undergoing laparoscopic cholecystectomy.Trial registration The trial was registered prior to patient enrollment at https://register.clinicaltrials.gov (NCT04224532, Date of the registration: January 8, 2020).

The Role of Transocular Ultrasound in the Assessment of Neurotoxicity-Related Encephalopathy in Mushroom Poisoning

ObjectiveMushroom poisonings can lead to life-threatening organ dysfunctions and neurotoxicity-related encephalopathy. This study aimed to detect increased intracranial pressure by measuring optic nerve sheath diameter (ONSD) ultrasonographically and to determine its association with clinical and laboratory parameters.MethodsIn this prospective case-control study, we evaluated the patients aged above 18 years who presented to the emergency department with mushroom poisoning. Vital signs, clinical and laboratory parameters and ONSD of both eyes measured with transocular ultrasound were noted at initial admission and the 24th hour.ResultsWe measured ONSD in 26 cases with mushroom poisoning and 26 healthy volunteers. Baseline ONSD measurements of the poisoning group were significantly higher than those of the control group (5.94±0.73 vs. 4.11±0.64, p<0.0001). ONSD values significantly regressed at 24th hour compared with the baseline measurements in the poisoning group (5.94±0.73 vs. 5.06±0.56, p<0.001).The ONSD values were significantly higher in patients who had a clinical picture of encephalopathy compared with patients who didn’t have (6.05±0.72 vs. 4.36±1.03, p<0.001). No significant deterioration was observed in ammonium levels, hepatic and renal functions of the patients.ConclusionWe detected increased ONSDs in patients with mushroom poisoning compared with those in the control healthy volunteers. Our findings suggest that ONSD, measured by ultrasonography, may be safely and effectively used to diagnose transient encephalopathy associated with neurotoxicity.

High-fidelity Training Model for Measurement of Dynamic Optic Nerve Sheath Diameter Using Transorbital Ultrasonography.

Transorbital ultrasonographic measurement of optic nerve sheath diameter (ONSD) is an important technique for bedside assessment of raised intracranial pressure (ICP). However, developing competency for this clinical skill requires practice scans on both normal subjects and patients with raised ICP. The aim of this study is to develop a high-fidelity training model capable of measuring dynamic changes in ONSD and to test the reliability and reproducibility of the model at different simulated ICP values. We designed and developed a high-fidelity training model for dynamic ONSD measurement using a hemispherical table tennis ball, mounted on a 3.0-mm pediatric microcuffed endotracheal tube (ETT). Two independent investigators then performed a randomized blinded study to assess the reliability and reproducibility of the model. A total of 30 ONSD measurements (10 measurements each for 3 ETT cuff volumes of 0.1, 0.2, and 0.3 mL, simulating an ONSD of a normal, borderline, and raised ICP, respectively) were performed by each investigator. Intraclass correlation coefficients and Bland-Altman plots were calculated to analyze the level of agreement between the investigators. Our model was able to provide dynamic changes in ONSD secondary to ETT cuff volume changes. Small increments of 0.1 mL cuff volume changes produced immediate changes in ONSD that are similar to those observed in patients. The median interobserver difference in ONSD was 0.3 mm (interquartile range, 0. to 0.4 mm). Intraclass correlation coefficient was 0.89, 0.89, and 0.90 for 0.1, 0.2, and 0.3 mL ETT cuff volumes, respectively. We have developed a clinically relevant model capable of simulating changes in ONSD in patients with normal and raised ICP. This model could be a valuable training tool to gain scanning experience in optic nerve ultrasonography, and improve operators' technical abilities.

Diagnostic and prognostic value of the optic nerve sheath diameter with respect to the intracranial pressure and neurological outcome of patients following hemicraniectomy

BackgroundIn cases showing cerebrospinal fluid (CSF) redistribution as a compensatory mechanism in acute intracranial hypertension, the optic nerve sheath diameter (ONSD) can be used to estimate intracranial pressure (ICP). However, it remains unclear whether the ONSD can be applied in patients with skull defects after a craniectomy, because the primary injury or surgical craniectomy may alter the dynamics of the CSF circulation or structure of the optical nerve sheath. This study explored the value of the ONSD in patients after a hemicraniectomy.MethodsThis prospective observational study enrolled patients after a hemicraniectomy. All patients underwent invasive ICP monitoring and ocular ultrasound within 6 h postoperatively. We followed the patients for 6 months and evaluated them using the Glasgow Outcome Score (GOS), classifying the outcome as favorable (GOS 4–5) or unfavorable (GOS 1–3). We evaluated the ONSD in both according to the ICP and neurological outcome.ResultsOf the 33 enrolled patients, 20 (60.6%) had an unfavorable outcome at 6 months. Disagreement was seen in the ONSD measurements between the eyes [craniectomy side (ONSDips) and opposite side (ONSDcon)]. The intraclass correlation coefficient between ONSDips and ONSDcon was 0.745 (p < 0.001). ONSD had no significant correlation with ICP in Spearman correlation analysis (ONSDips r = 0.205, p = 0.252; ONSDcon r = 0.164, p = 0.362). Receiver operator characteristic (ROC) curve analysis revealed that the GCS, Helsinki computed tomography (CT) score, pupil reaction, and ONSDcon measured after the craniectomy were significantly associated with a poor outcome. ONSDcon > 5.5 mm predicted a poor outcome, with an area under the ROC curve of 0.717 (95% confidence interval, 0.534–0.860, p = 0.02), 70% sensitivity, and 69.2% specificity.ConclusionsAfter hemicraniectomy, the ONSD measured on ultrasound was unreliable for evaluating ICP, but showed potential prognostic value for a poor neurological outcome.

Effect of Mannitol on Ultrasonographically Measured Optic Nerve Sheath Diameter as a Surrogate for Intracranial Pressure During Robot-Assisted Laparoscopic Prostatectomy with Pneumoperitoneum and the Trendelenburg Position.

CO2 pneumoperitoneum and the steep Trendelenburg position during robot-assisted laparoscopic prostatectomy (RALP) can increase intracranial pressure (ICP). Mannitol is widely used to treat increased ICP. However, no studies to date have specifically evaluated the effect of mannitol on ICP in patients undergoing RALP. Ultrasonographic measurement of the optic nerve sheath diameter (ONSD) is considered a reliable technique to noninvasively evaluate the ICP. Therefore, this study compared ONSDs as a surrogate for ICP before and after mannitol administration in prostate cancer patients undergoing RALP. Mannitol (0.5 g/kg) was administered after pneumoperitoneum establishment and shifting to the Trendelenburg position. ONSDs were measured at six predetermined time points: 10 minutes after anesthesia induction (T0); 5 minutes after pneumoperitoneum and the Trendelenburg position before mannitol administration (T1); 30 minutes (T2), 60 minutes (T3), and 90 minutes (T4) after completion of mannitol administration during pneumoperitoneum and the Trendelenburg position; and at skin closure in the supine position (T5). Moreover, intraoperative hemodynamic and respiratory variables were evaluated simultaneously. Thirty-six patients were analyzed. ONSDs were significantly lower at T2, T3, and T4 than at T1 (all p < 0.001), with the greatest decrease observed at T4 compared with T1 (4.46 ± 0.2 mm vs 4.81 ± 0.3 mm, p < 0.001). Regional cerebral oxygen saturation, cardiac output, corrected flow time, peak velocity, body temperature, arterial CO2 partial pressure, peak airway pressure, plateau airway pressure, dynamic compliance, and static compliance were not significantly different during pneumoperitoneum and the Trendelenburg position; however, mean arterial blood pressure and heart rate were significantly different. Mannitol decreases the ONSD in patients undergoing RALP with CO2 pneumoperitoneum and the steep Trendelenburg position. This result provides useful information on the beneficial effects of mannitol administration on prostate cancer patients who may develop increased ICP during RALP.

Use of neuroimaging measurements of optic nerve sheath diameter to assess intracranial pressure in craniosynostosis.

This study aims to evaluate accuracy of optic nerve sheath diameter (ONSD) measurements obtained by magnetic resonance imaging (MRI) in patients with craniosynostosis (CS) for detection of high intracranial pressure (ICP) and to correlate MRI-derived ONSD measurements with those obtained by computed tomography (CT) scans in CS patients. A retrospective review was conducted on CS patients who had MRI- and age-matched controls with normal MRI. Diagnosis of intracranial hypertension was based on presence of papilledema, direct ICP monitoring, and/or lumbar puncture. The search also included patients with MRI and CT done within 30days apart. ONSDs were measured 3mm behind the globe on both modalities. The study identified 56 CS patients (mean age 3.8 ± 3.47years) and 49 controls (mean age 3.7 ± 3.62years). Mean ONSD in patients with high ICP was significantly higher than in patients without high ICP (P = 0.0001) and in controls (P < 0.0001). The optimal ONSD threshold for predicting raised ICP in patients >1year old was 6mm (71.4% sensitivity, 89.7% specificity). Nineteen patients with 38 single-eye MRI/CT pairs were identified. Substantial agreement between both modalities resulted (r = 0.959, 95% CI 0.923-0.978), and Bland and Altman Plot analysis showed that 95% of measurements fell within limits of agreement (1.96 SD; ± 0.6mm). In CS patients, ONSD measured by MRI represent indirect non-invasive means of ICP assessment. Both MRI and CT measurements of ONSD gave comparable results, and the use of CT-derived ONSD measurements may give some idea about ICP in CS patients.

AGREEMENT BETWEEN MEASURING OPTIC NERVE SHEATH DIAMETER BY ULTRASONOGRAPHY AND BRAIN CT SCAN AMONG PATIENTS WITH TRAUMATIC BRAIN INJURY

Objective: Previous studies have shown that measuring the optic nerve sheath diameter (ONSD) can be a useful indicator in cases with ICP rising. The present study was designed to determine the agreement rate between performing Ultrasound (US) compared to Brain Computed Tomography (CT) scanning in the diagnosis of ICP rising through measuring the ONSDamong patients with traumatic brain injury. Methods: The present study was a cross-sectional study performed among patients with head trauma during a six-month period in the year 2015. All of the included patients had an indication of performing brain CT. The optic nerve ultrasonography wasperformed by an expert emergency medicine specialist who was blinded to the results of brain CT scan in these patients. The result of ONSD in US and brain CT scan were measured by one radiologist who was unaware of the study, and finally the kappa coefficient for the results of ONSD in US and brain CT were calculated. Results: 60 patients with head trauma (70% male) with a mean age of 36.4 ± 15.5 years were investigated.The kappa coefficient agreement between results of performing US and brain CT scan to measure ONSD was 85.7%. The p value for Mc-Nemar test was obtained 1.0 revealed that there was no evidence against the agreement between results of US and CT scan in our patients. Conclusion: The results showed that there was an excellent agreement between US and brain CT scan for the diagnosis of ICP rising through measuring ONSD in patients with head trauma.

The correlation between optic nerve sheath diameter and volume status in patients after cardiac surgery

Objective: To investigate the relationship between optic nerve sheath diameter (ONSD) and volume status of patients after cardiac surgery. Methods: A total of consecutive 56 patients who were treated in Critical Care Unit in Peking Union Medical College Hospital after open heart surgery from January to August 2015 were screened in this study. Central venous pressure (CVP) and 72 h net fluid balance were monitored. ONSD and diameter of inferior vena cava (IVC) were measured by ultrasound. Results: A total of 44 patients were finally included in the study. The postoperative baseline ONSD was (5.31±1.96)mm, compared to (5.07±1.77)mm after 72 h treatment, with ΔONSD(0.22±0.21)mm. Baseline and post-treatment at 72 h CVP were (11.98±4.09)mmHg and (8.95±4.02)mmHg respectively. IVC dropped from (19.75±4.12)mm to (17.11±4.68)mm. ΔONSD and ΔCVP were significantly correlated (r=0.422, P<0.05), ΔONSD and net fluid balance (NFB) at 72 h were significantly correlated (r=-0.388, P<0.05). While ΔONSD were significantly correlated with ΔIVC (r=0.423, P<0.05), ΔCVP and ΔIVC were also significantly correlated (r=0.391, P<0.05). Conclusion: The change of ONSD in patients after cardiac surgery is related to the change of volume status. Therefore ONSD is helpful to estimate brain edema, not only could be a potential index to evaluate volume status, but also be used to guide improving prognosis after cardiac surgery.

Transocular ultrasound measurement of the optic nerve sheath diameter can identify elevated intracranial pressure in trauma patients

Background Prompt identification of elevated intracranial pressure (eICP) is life-saving. Physical exam alone often fails to identify this problem and invasive monitoring is not always utilized appropriately. A non-invasive, rapid, reliable technique to detect eICP is needed and optic nerve sheath diameter (ONSD) is known to be a valid surrogate. Historically, ONSD in patients with eICP above 20 mmHg varied from 0.5 to 0.7 cm. Receiver operator curves predict that diameters below 0.5 to 0.58 cm correspond to normal pressures. Interobserver variability is low (0.01--0.03 cm). The learning curve was 25 and 10 procedures for novice and experienced sonographers, respectively. We report our initial experience using ultrasound to measure ONSD during initial trauma evaluation. Study design Transocular ultrasound was used to determine ONSD after traumatic brain injury. Data were correlated with CT and exam findings or measured ICP. Measurements were performed by a single trauma surgeon. Time to perform the measurement was recorded. Relevant literature from the past 15 years was reviewed. Results Physical exam was not a reliable indicator of eICP. In patients with eICP requiring surgery, ONSD averaged 0.62 cm. Normal pressures were ensured if the ONDS was &lt;0.50 cm (95% CI 0.469–0.540 cm, p &lt; 0.001). Intraobserver variability was low (0.01--0.02 cm). Average time to perform the exam was less than 2 min. Conclusions Determining ONSD with ultrasound is easy to learn, precise, and inexpensive. An ONSD of less than 5 mm ensures no eICP. This procedure can be added to the evaluation of trauma patients with no delay in care. Future prospective studies may validate and incorporate this technique into the trauma surgeon's armamentarium.