Bedside sonographic measurement of optic nerve sheath diameter as a predictor of intracranial pressure in ED

Monitoring of optic sheath diameter during acute migraine attack: an objective criteria for the severity of disease

BACKGROUND

The etiology of migraine can be complex and multifactorial but not clear, also, intracranial pressure has been already associated with migraine attacks. This study aimed to monitor intracranial pressure during migraine attack to understand the possible relations with disease and severity.

METHODS

A prospective randomized study was designed. Patients with a definitive diagnosis of migraine underwent ultrasonography for optic nerve sheath diameter (ONSD) measurement before treatment and were re-measured after the attack was resolved. The severity of the migraine was assessed with Headache Impact Test-6 (HIT-6) and Migraine Disability Assessment (MIDAS) questionnaire before the treatment and after the symptoms regressed. ONSD values and scores from the questionnaires were compared before and after the migraine attack.

RESULTS

The study included 11 (52.4%) women and 10 (47.6%) men, and 42 eyes were evaluated. ONSD was detected as 4.23 ± 0.26 mm in the right eye and 4.10 ± 0.32 mm in the left eye during the migraine attack and decreased to 3.65 ± 0.41 mm in the right eye and 3.50 ± 0.33 mm in the left eye after the attack was treated (p < 0.001, both). A similar statistical improvement was found in HIT-6 and MIDAS scores with ONSD after treatment (p < 0.001). A significant positive correlation was found between the ONSD value in both eyes and HIT-6/MIDAS scores during the migraine attack, and also, after the migraine attack.

CONCLUSION

A subjective increase of ONSD values during the migraine attack decreased after the disease resolved, also changes in ONSD values were significantly correlated with the severity of symptoms.

Measurement of optic nerve sheath diameter on computed tomography for the differentiation of transient ischemic attacks

OBJECTIVE

The objective of this study was to investigate whether the measurement of mean optic nerve sheath diameter in patients with transient ischemic attack could be used to distinguish between control groups, the acute ischemic stroke group, and subgroups within the acute ischemic stroke category.

METHODS

Retrospectively, the mean optic nerve sheath diameters of patients aged 18 years and older belonging to control, transient ischemic attack, acute ischemic stroke, and subgroups within the acute ischemic stroke category were measured with initial computed tomography conducted in the emergency department.

RESULTS

Out of the 773 patients included in the study, 318 (41.1%) were in the control group, 77 (10%) had transient ischemic attack, and 378 (49%) were categorized as stroke patients. The average mean optic nerve sheath diameter was significantly higher in both the stroke and transient ischemic attack groups compared with the control group (p<0.001 for both comparisons). Furthermore, the mean optic nerve sheath diameter in the stroke subgroups was significantly higher than in both the transient ischemic attack and control groups (p<0.001 for all comparisons). In transient ischemic attack patients, the mean optic nerve sheath diameter showed a significant ability to predict transient ischemic attack (AUC=0.913, p<0.001), with a calculated optimal cutoff value of 4.72, sensitivity of 94.8%, and specificity of 73.9%.

CONCLUSION

The mean optic nerve sheath diameter of patients in the transient ischemic attack group was lower compared with those in the stroke subgroups but higher compared with the control group.

Optic Nerve Sheath Diameter for Assessing Prognosis after Out-of-Hospital Cardiac Arrest

PURPOSE

Evaluate optic nerve sheath and pial diameters (ONSD, ONPD) via sonography and computed tomography (CT) after out-of-hospital cardiac arrest (CA) and to compare their prognostic significance with other imaging and laboratory biomarkers.

MATERIALS AND METHODS

A prospective observational study enrolling patients after successful resuscitation between December 2017 and August 2021. ONSD and ONPD were measured with sonography. Additionally, ONSD, and also grey-to-white ratio at basal ganglia (GWRBG) and cerebrum (GWRCBR), were assessed using CT. Lactate and neuron specific enolase (NSE) blood levels were measured.

RESULTS

Sonographically measured ONSD and ONPD yielded no significant difference between survival and non-survival (p values ≥0.4). Meanwhile, CT assessed ONSD, GWRBG, GWRCBR, and NSE levels significantly differed regarding both, survival (p values ≤0.005) and neurological outcome groups (p values ≤0.04). For survival prognosis, GWRBG, GWRCBR, and NSE levels appeared as excellent predictors; in predicting a good neurological outcome, NSE had the highest accuracy.

CONCLUSIONS

CT diagnostics, in particular GWRBG and GWRCBR, as well as NSE as laboratory biomarker, appear as excellent outcome predictors. Meanwhile, our data lead us to recommend caution in utilizing sonography assessed ONSD and ONPD for prognostic decision-making post-CA.

Development and evaluation of a point-of-care ocular ultrasound curriculum for medical students - a proof-of-concept study

BACKGROUND

Point-of-care Ocular Ultrasound (POCOUS) has gained importance in emergency medicine and intensive care in recent years. This work aimed to establish and evaluate a dedicated ultrasound education program for learning POCOUS-specific skills during medical studies at a university hospital.

METHODS

The blended learning-based program (6 teaching units) based on recent scientific publications and recommendations was developed for students in the clinical part of their medical studies. Experts and trainers consisted of physicians from the Ear-Nose-Throat, radiology, ophthalmology and neurology specialties as well as university educational specialists. Lecture notes containing digital video links for preparation was produced as teaching material. In total, 33 students participated in the study. The education program, including the teaching materials, motivation and subjective gain in competency, was evaluated with the aid of a questionnaire (7-point Likert response format). Objective learning success was assessed on the basis of pre- and post-tests. These covered the skill areas: "anatomical basics", "ultrasound basics", "understanding of cross-sectional images", "normal findings" and "pathology recognition".

RESULTS

In the objective assessment of image interpretation, the participants improved significantly (p < 0.001) from pre- to post-test with a large effect size (Cohen's d = 1.78, effect size r = 0.66). The evaluations revealed a high level of satisfaction with the course concept, teaching materials and the tutors. In addition, a high level of motivation was recorded in relation to continuing to study "ultrasound diagnostics" and "ophthalmologic diseases". A significant (p < 0.01) positive gain was also achieved in terms of the subjective assessment of competency. This covers areas such as expertise, sonographic anatomy and performing a POCOUS examination as well as recognizing retinal detachment, globe perforation and increased optic nerve sheath diameter.

CONCLUSION

The results of this feasibility study show that medical students accept and support a POCOUS-specific education program and are able to develop a higher objective and subjective level of competency. Future transfer to other sites and larger groups of participants seems feasible.

Efficacy of bedside optic nerve sheath diameter measurement in differentiating provoked seizure from unprovoked seizure in the emergency department

BACKGROUND

Emergency departments (EDs) are typically the first medical contact for seizure patients, and early diagnosis and treatment is primarily the responsibility of emergency physicians.

OBJECTIVES

Demonstrate the efficacy of bedside ocular ultrasonography for optic nerve sheath diameter (ONSD) measurement in differentiating provoked seizure from unprovoked seizure in the ED.

DESIGN

Prospective observational study SETTINGS: Tertiary care hospital PATIENTS AND METHODS: Patients presenting to the ED with seizure were divided into two groups according to medical history, physical examination, laboratory results, cranial computed tomography findings and electroencephalography results. Patients with seizures that did not have a specific cause (unprovoked) were compared with patients who had seizures caused by underlying pathology (provoked). The measurement of the ONSD was taken at the bedside within 30 minutes of arrival. The study compared the ONSD values, age, sex, type of seizure, and Glasgow Coma Score between the two groups.

MAIN OUTCOME MEASURE

Efficacy of ONSD to distinguish between provoked and unprovoked seizures.

SAMPLE SIZE

210 patients RESULTS: One hundred and fourteen (54.3%) patients were in the provoked seizure group and 96 (45.7%) were in the unprovoked seizure group. The ONSD measurements were significantly higher in the provoked seizure group compared with the unprovoked seizure group (median 6.1 mm vs. 5.2 mm, P<.001). The cut-off value of ONSD higher than 5.61 was significantly associated with the prediction of the provoked seizure (P<.001). The area under the curve value was 0.882 (95% CI: 0.830-0.922) with a sensitivity of 86.5 and specificity of 78.9%.

CONCLUSIONS

Bedside ONSD measurement by means of ocular ultrasound is an effective method for differentiating provoked seizure from unprovoked seizure.

LIMITATIONS

Statistical significance of age on ONSD and exclusion of pediatric patients.

CONFLICT OF INTEREST

None.

The value of the optic nerve sheath diameter measured using computerized brain tomography in the evaluation of mortality status in patients admitted to the emergency department with intracranial hemorrhage

Background/Aim: The optic nerve sheath diameter (ONSD) measurement is a non-invasive method that can be obtained from computerized tomography (CT) images. It can therefore be a useful diagnostic tool in determining prognosis in the emergency department. The aim of this study was to investigate the relationship between ONSD and mortality status in patients with intracranial hemorrhage who presented to the emergency department by measuring ONSD on computerized brain tomography images taken during admission. Methods: This retrospective cohort study was carried out in the emergency department of a tertiary hospital between December 1, 2018 and December 1, 2020 and included intracranial hemorrhage patients and patients with normal brain CT scans that had been obtained for any reason. Bilateral ONSDs were measured in both the intracranial hemorrhage and control groups. We first evaluated whether ONSD would differ between the two groups after which the relationship between ONSD and mortality was analyzed in the patient group who presented with bleeding. Results: Intracranial hemorrhage was present in half the cases and midline shift in 21.5%. A statistically significant increase in ONSD was observed in cases with intracranial hemorrhage (P < 0.001). Similarly, a statistically significant increase in ONSD was found in cases with midline shifts and mortality (P < 0.001). A cut-off value of 4.19 mm for mean optic nerve diameter exhibited 100% sensitivity and 70% specificity in terms of hemorrhage detection (area under the curve [AUC]: 0.952; P < 0.001). A cut-off value of 6.03 mm for ONSD exhibited 76% sensitivity and 74% specificity in terms of hemorrhage detection (AUC: 0.730; P = 0.001). The odds ratio for prediction of mortality based on a regression analysis was 8.838 in cases with intracranial hemorrhage (P < 0.001). Conclusion: ONSSD measured on CT images is a promising tool for prediction of intracranial hemorrhage, midline shift, and mortality status.

Ultrasound Detection of Intracranial Hypertension in Brain Injuries

In recent years, the measurement of optic nerve sheath diameter with ultrasound to detect the presence of increased intracranial pressure has widely spread. It can be qualitatively and effectively used to identify intracranial hypertension. Intracranial pressure can rise due to acute injury, cerebral bleeding, hydrocephalus, brain tumors and other space-occupying abnormalities, and it is linked to a high death rate. The purpose of this review is to give a general overview of the most relevant scientific publications on ultrasonographic evaluation of the optic nerve in case of brain injuries published in the last 30 years, as well as to analyze the limits of the most extensively used B-scan approach. Fifty-two papers chosen from the PubMed medical database were analyzed in this review. Our findings revealed that ocular ultrasound is an useful diagnostic tool in the management of intracranial hypertension when it exceeds a certain value or after head trauma. As a result, an ultrasound of the optic nerve can be extremely helpful in guiding diagnosis and treatment. The blooming effect is one of the most critical restrictions to consider when using B-scan ultrasonography. Since amplitude-scan ultrasound, also known as A-scan, does not have this limit, these two diagnostic techniques should always be used together for a more full, accurate, and trustworthy ultrasound examination, ensuring more data objectivity.

Monitoring of optic nerve sheath diameter on computed tomography for noninvasive assessment of intracranial pressure: Case report: Optic nerve sheath and intracranial pressure

Introduction: It is important to measure intracranial pressure because traumatic brain injuries lead to intracranial hypertension and ischaemic brain lesions. The gold standard for measurement of intracranial pressure is invasive methods, but they can lead to complications and are not always available. Measurement of the optic nerve sheath diameter is a useful noninvasive way to estimate intracranial pressure and it can be done via ultrasonography, computed tomography and magnetic resonance imaging. Increased optic nerve sheath diameter on computed tomography can help to diagnose intracranial hypertension and to verify the need for urgent therapy and invasive measurements. Case report: We present 74 years old patient with traumatic brain injury and intracranial bleeding. Optic nerve sheath diameter was 6.81 mm on the left and 6.83 mm on the right side on the initial scan. In the coming days, existing haematomas were enlarged and there were newly formed haematomas, so there were changes in the optic nerve sheath diameter. After the haematoma evacuation, the sheath diameter was 6.56 mm on the left and 6.47 mm on the right side. At the time of the second neurologic deterioration, the sheath diameter was 7.43 mm on the left and 7.25 mm on the right side. On the 25th day, the diameter was 6.72 mm on the left and 6.41 mm on the right side. Conclusion: Measurement of the optic nerve sheath diameter is a significant additional diagnostic method for the assessment of intracranial hypertension and can help to decide on further treatment.

Optic Nerve Sheath Ultrasound for the Detection and Monitoring of Raised Intracranial Pressure in Tuberculous Meningitis

BACKGROUND

Neurological complications of tuberculous meningitis (TBM) often lead to raised intracranial pressure (ICP) resulting in high morbidity and mortality. Measurement of optic nerve sheath diameter (ONSD) by point-of-care ultrasound may aid in the identification of raised ICP in TBM.

METHODS

From June 2017 to December 2019, 107 Vietnamese adults with TBM, enrolled in the ACT HIV or LAST ACT trials (NCT03092817, NCT03100786), underwent ONSD ultrasound at ≥1 of days 0, 3, 7, 14, 21, and day ±30 after enrollment. Demographic data, TBM severity grade, HIV coinfection status, and clinical endpoints by 3 months were recorded. ONSD values were correlated with disease severity, baseline brain imaging, cerebrospinal fluid parameters, and clinical endpoints.

RESULTS

267 ONSD ultrasound scans were performed in 107 participants over the first 30 days of treatment, with measurements from 0.38-0.74 cm. Paired baseline ONSD and brain imaging were performed in 63 participants. Higher baseline ONSD was associated with more severe disease and abnormal brain imaging (abnormal imaging 0.55 cm vs 0.50 cm normal imaging, P = .01). Baseline median ONSD was significantly higher in participants who died by 3 months (0.56 cm [15/72]) versus participants who survived by 3 months (0.52 cm [57/72]) (P = .02). Median ONSD was higher at all follow-up times in participants who died by 3 months.

CONCLUSIONS

Higher ONSD was associated with increased disease severity, brain imaging abnormalities, and increased death by 3 months. ONSD ultrasound has a potential role as a noninvasive, affordable bedside tool for predicting brain pathology and death in TBM.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Relationship between internal carotid artery stenosis grade and optic nerve sheath diameter measured by transorbital ultrasonography

PURPOSE

To assess the consequence of the presence, grade, and asymmetry of carotid artery stenoses on the optic nerve sheath diameter (ONSD) measured by ultrasonography.

METHODS

ONSD was measured with B-mode ultrasonography in 129 patients referred for duplex and color Doppler imaging of the carotid arteries. Internal carotid artery stenosis was graded on the basis of peak systolic flow velocity.

RESULTS

The mean ONSD was 3.04 ± 0.38 mm in the patients without or with <50% internal carotid artery stenosis and 2.46 ± 0.35 mm in those with >70% stenosis. There was an average difference of 0.58 mm between the ONSD of the patients with <50% and the patients with >70% stenosis.

CONCLUSION

ONSD is lower in patients with carotid artery stenosis. Carotid arteries should be investigated, especially in patients with cardiovascular risk factors or diseases, before interpreting ONSD values.

Mean value of B-mode optic nerve sheath diameter as an indicator of increased intracranial pressure: a systematic review and meta-analysis

Objectives

Timely diagnosis and treatment of increased intracranial pressure can decrease morbidity and prevent mortality. The present meta-analysis aims to determine the mean value of the ONSD measured in patients with various elevated ICP etiologies under different clinical settings, as well as comparing the value of ONSD between patients with and without elevated ICP.

Methods

This meta-analysis complied with the Preferred Reporting Items for Systematic Reviews and Meta-analysis Statement8. PubMed, Embase, and Cochrane Library were searched to identify ONSD measured by US for patients with increased ICP from establishment to October 2020.

Results

A total of 779 patients with elevated ICP among 22 studies were included in the present meta-analysis. Studies were published between 2003 and 2020. Eighteen were comparative (18/22, 81.8%), and four were single-armed study (4/22, 18.2%). Twenty were prospective studies (20/22, 90.9%). There was moderate-to-high heterogeneity based on the prediction ellipse area and variance logit of sensitivity and specificity.

Conclusions

The mean value of the ONSD among patients diagnosed with increased ICP was 5.82 mm (95% CI 5.58–6.06 mm). Variations were observed based on etiology of intracranial hypertension, clinical settings where ONSD was measured, and standards for diagnosing intracranial hypertension. The US-ONSD among patient with elevated ICP was significantly higher than the normal control. Although a cut-off value is not clearly determined, these mean values can be implemented to evaluate the sensitivity and specificity of US-ONSD in diagnosing intracranial hypertension in future studies.

Estimation of intracranial pressure by ultrasound of the optic nerve sheath in an animal model of intracranial hypertension

BACKGROUND

Ultrasound of the optic nerve sheath diameter (ONSD) has been used as a non-invasive and cost-effective bedside alternative to invasive intracranial pressure (ICP) monitoring. However, ONSD time-lapse behavior in intracranial hypertension (ICH) and its relief by means of either saline infusion or surgery are still unknown. The objective of this study was to correlate intracranial pressure (ICP) and ultrasonography of the optic nerve sheath (ONS) in an experimental animal model of ICH and determine the interval needed for ONSD to return to baseline levels.

METHODS

An experimental study was conducted on 30 pigs. ONSD was evaluated by ultrasound at different ICPs generated by intracranial balloon inflation, saline infusion, and balloon deflation, and measured using an intraventricular catheter.

RESULTS

All variables obtained by ONS ultrasonography such as left, right, and average ONSD (AON) were statistically significant to estimate the ICP value. ONSD changed immediately after balloon inflation and returned to baseline after an average delay of 30 min after balloon deflation (p = 0.016). No statistical significance was observed in the ICP and ONSD values with hypertonic saline infusion. In this swine model, ICP and ONSD showed linear correlation and ICP could be estimated using the formula: -80.5 + 238.2 × AON.

CONCLUSION

In the present study, ultrasound to measure ONSD showed a linear correlation with ICP, although a short delay in returning to baseline levels was observed in the case of sudden ICH relief.

Ultrasonographic measurement of the optic nerve sheath in the differential diagnosis and follow-up of migraine with and without aura: A pilot study

OBJECTIVE

Headache continues to be a common cause of emergency admissions. At first glance, primary headaches may not be distinguished from secondary headaches. This study aimed to evaluate the use of ultrasonic measurement of optic nerve sheath diameter (ONSD) in the clinical diagnosis of migraine patients during attack and during periods without attacks.

PATIENTS AND METHODS

This prospective study was conducted at the emergency department and neurology outpatient clinic of a tertiary hospital between October 2019 and January 2020. Patients diagnosed with episodic migraine and between ages 18-60 were included in the study. Migraine diagnosis and classification were based on criteria from the 2018 International Classification of Headache Disorders. ONSD measurement was performed with ultrasonography. ONSD measurements of the same migraine patients during attack and attack-free periods were compared with measurements of healthy volunteers.

RESULTS

A total of 82 participants consisting of 42 migraine patients and 40 control subjects were evaluated. In the control group, mean ONSD of the right eye was 4.88 ± 0.31 mm and mean ONSD of the left eye was 4.86 ± 0.31 mm. Mean ONSD measurement of the left eye was 4.80 ± 0.36 mm and mean ONSD of the right eye was 4.82 ± 0.37 during the attack period of the migraine patients. There was no significant difference between the migraine patients and the control group according to right and left eye ONSD measurements (attack-free period: p = 0.200, p = 0.448; attack period: p = 0.338, p = 0.660, respectively). There was no significant difference between ONSD measurements during the attack period and attack-free period in migraine patients (right eye p = 0.32; left eye p = 0.532).

CONCLUSION

The results of our study indicate that ONSD measurements may provide clinical insight into differential diagnosis preceding neuroimaging in migraine patients. On the other hand, since our study is the first on this topic, it should be noted that further studies are needed to come to a conclusion.

Comparative and retrospective evaluation of the predictive performance of optic nerve sheath thickness and optic nerve sheath diameter for traumatic brain injury using facial computed tomography

OBJECTIVE

To evaluate the predictive performance of optic nerve sheath thickness (ONST) on the outcomes of traumatic brain injury (TBI) and to compare the inter-observer agreement To evaluate the predictive performance of optic nerve sheath thickness (ONST) for traumatic brain injury (TBI) and to compare the predictive performance and inter-observer agreement between ONST and optic nerve sheath diameter (ONSD) on facial computed tomography (CT).

METHODS

We retrospectively enrolled patients with a history of facial trauma and who underwent both facial CT and brain CT. Two reviewers independently measured ONST and ONSD of each patient using facial CT images. Final brain CT with clinical outcome was used as the reference standard for TBI. Multivariate logistic regression analyses, receiver operating characteristic (ROC) curves, and intraclass correlation coefficients were used for statistical analyses.

RESULTS

Both ONST (P=0.002) and ONSD (P=0.001) on facial CT were significantly independent factors to distinguish between TBI and healthy brains; an increase in ONST and ONSD values corresponded with an increase in the risk of TBI by 8.9- and 7.6-fold, respectively. The predictive performances of the ONST (sensitivity, 96.2%; specificity, 94.3%; area under the ROC curve, 0.968) and ONSD (sensitivity, 92.6%; specificity, 90.2%; area under the ROC curve, 0.955) were excellent and exhibited similar sensitivity, specificity, and area under the curve (P=0.18-0.99). Interobserver and intraobserver intraclass correlation coefficients for ONST were significantly higher than those for ONSD (all P<0.001).

CONCLUSION

ONST on facial CT is a feasible predictor of TBI and demonstrates similar performance and superior observer agreement than ONSD. We recommend using ONST measurements to assess the need for additional brain CT scans in TBI-suspected cases.

Pseudotumour Cerebri Syndrome in China: A Cohort Study

Pseudotumour cerebri syndrome (PTCS) remains to be fully investigated in Chinese patients and our study reported PTCS-related clinical differences between Chinese patients and Western patients. This study enrolled 55 consecutive patients (females: 44, median age: 37 y, age range: 14–62 y) with PTCS diagnosed from October 2015 to December 2017. Nine (16.4%, females) patients had primary PTCS, and 46 (83.6%) had secondary PTCS (P = 0.001). At presentation, 81.8% of patients had grade >3 papilloedema, with 23.6% having diffusely constricted fields. Mean subarachnoid space around the optic nerve measured by retrobulbar ultrasonography during lumbar puncture was 1.12 ± 0.17 mm and decreased to 0.86 ± 0.11 mm after treatment. Optical coherence tomography (OCT) showed that 92.9% of eyes with intact macular ganglion cell-inner plexiform layer (GCIPL) at baseline had good outcomes after treatment. Patients’ demographic and clinical characteristics showed that secondary PTCS was more common than primary idiopathic intracranial hypertension in Chinese patients. Polycystic ovarian syndrome was the main associated factor in females. Poor visual function was common at presentation. Noninvasive ocular ultrasonography and OCT are the prognostic indicators of PTCS treatment in intracranial pressure and visual function, respectively, after PTCS treatment.

Bedside Optic Nerve Ultrasonography for Diagnosing Increased Intracranial Pressure: A Systematic Review and Meta-analysis

BACKGROUND

Optic nerve ultrasonography (optic nerve sheath diameter sonography) has been proposed as a noninvasive, quick method for diagnosing increased intracranial pressure.

PURPOSE

To examine the accuracy of optic nerve ultrasonography for diagnosing increased intracranial pressure in children and adults.

DATA SOURCES

13 databases from inception through May 2019, reference lists, and meeting proceedings.

STUDY SELECTION

Prospective optic nerve ultrasonography diagnostic accuracy studies, published in any language, involving any age group or reference standard.

DATA EXTRACTION

3 reviewers independently abstracted data and performed quality assessment.

DATA SYNTHESIS

Of 71 eligible studies involving 4551 patients, 61 included adults, and 35 were rated as having low risk of bias. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of optic nerve ultrasonography in patients with traumatic brain injury were 97% (95% CI, 92% to 99%), 86% (CI, 74% to 93%), 6.93 (CI, 3.55 to 13.54), and 0.04 (CI, 0.02 to 0.10), respectively. Respective estimates in patients with nontraumatic brain injury were 92% (CI, 86% to 96%), 86% (CI, 77% to 92%), 6.39 (CI, 3.77 to 10.84), and 0.09 (CI, 0.05 to 0.17). Accuracy estimates were similar among studies stratified by patient age, operator specialty and training level, reference standard, sonographer blinding status, and cutoff value. The optimal cutoff for optic nerve sheath dilatation on ultrasonography was 5.0 mm.

LIMITATION

Small studies, imprecise summary estimates, possible publication bias, and no evaluation of effect on clinical outcomes.

CONCLUSION

Optic nerve ultrasonography can help diagnose increased intracranial pressure. A normal sheath diameter measurement has high sensitivity and a low negative likelihood ratio that may rule out increased intracranial pressure, whereas an elevated measurement, characterized by a high specificity and positive likelihood ratio, may indicate increased intracranial pressure and the need for additional confirmatory tests.

PRIMARY FUNDING SOURCE

None. (PROSPERO: CRD42017055485).

Intracranial pressure in the American Alligator (Alligator mississippiensis): reptilian meninges and orthostatic gradients

The cranial meninges of reptiles differ from the more widely studied mammalian pattern in that the intraventricular and subarachnoid spaces are, at least partially, isolated. This study was undertaken to investigate the bulk flow of cerebrospinal fluid, and the resulting changes in intracranial pressure, in a common reptilian species. Intracranial pressure was measured using ocular ultrasonography and by surgically implanting pressure cannulae into the cranial subarachnoid space. The system was then challenged by: rotating the animal to create orthostatic gradients, perturbation of the vascular system, administration of epinephrine, and cephalic cutaneous heating. Pressure changes determined from the implanted catheters and through quantification of the optic nerve sheath were highly correlated and showed a significant linear relationship with orthostatic gradients. The catheter pressure responses were phasic, with an initial rapid response followed by a much slower response; each phase accounted for roughly half of the total pressure change. No significant relationship was found between intracranial pressure and either heart rate or blood flow. The focal application of heat and the administration of epinephrine both increased intracranial pressure, the latter influence being particularly pronounced.

The measurement of ultrasonographic optic nerve sheath diameter in patients with hyperglycemia

Background:

Diabetes mellitus is a disease associated with several complications in its acute and chronic stages.

Objective:

The aim of the study was to determine the treatment-associated changes in optic nerve sheath diameter in patients admitted to the emergency department due to one of the acute hyperglycemic complications of diabetes mellitus.

Materials and method:

Diabetic patients with serum glucose levels of 250 mg/dL or higher were included in the study. Healthy volunteers were included in the control group. Optic nerve sheath diameter was measured at 0th hour and at the end of the second hour. Blood samples were collected simultaneously with optic nerve sheath diameter measurements.

Results:

The study included 100 individuals. Group 1 included 50 patients and Group 2 included 50 healthy adults. Optic nerve sheath diameter was 4.5 ± 0.4 mm in Group 1 and 4.4 ± 0.5 mm in Group 2 in 0th hour, and no statistical difference was found between the groups (p = 0.162). In Group 1, optic nerve sheath diameter increased 0.6 ± 0.4 mm after the treatment. Of the patients in Group 1, 22 (44%) patients with diabetic ketoacidosis or hyperosmolar hyperglycemic state were assigned to Group 1A and 28 (56%) patients with isolated hyperglycemia were assigned to Group 1B. There was not a difference between the pre- and post-treatment optic nerve sheath diameter values of the patients in Group 1A and Group 1B. Optic nerve sheath diameter was observed to enlarge after treatment. The difference in optic nerve sheath diameter was 0.6 ± 0.4 mm in Group 1A and 0.5 ± 0.4 mm in Group 1B (p = 0.294).

Conclusion:

Pre-treatment optic nerve sheath diameter values of the patients who were diagnosed with one of the acute hyperglycemic complications of diabetes mellitus are not different from healthy adults. Furthermore, optic nerve sheath diameter values do not change with the severity of the disease. However, optic nerve sheath diameter values change with treatment. For this reason, optic nerve sheath diameter can be used to following the development of brain edema.

Increased Intracranial Pressure Damages Optic Nerve Structural Support

Optic nerve sheath diameter (ONSD) is used clinically as a noninvasive measure for elevated intracranial pressure (ICP). This study had two purposes: to investigate the immediate effects optic nerve sheath (ONS) dilation post-ICP increase on trabecular fibers connecting the optic nerve to the ONS and to document any changes in these fibers 30 days post-increased ICP. In a swine model, ICP was increased by inflating a Foley catheter balloon in the epidural space. Three control pigs received the catheter insertion without inflation (no increase in ICP) and four experimental pigs received the catheter with inflation (increased ICP). The control and two randomly selected pigs with increased ICP were euthanized immediately after the procedure. The two other pigs were euthanized 30 days post-catheter inflation. For all pigs, the ONS was removed and imaged using a scanning electron microscope, calculating percent porosity values. Porosity values for the experimental groups (Immediately measured [IM] μ = 0.5749; Delayed measured [DM] μ = 0.5714) were larger than the control group (μ = 0.4336) and statistically significant (IM vs. Control, p = 0.0018; DM vs. Control, p = 0.0092). There was no significant difference (p = 0.9485) in porosity of the DM group when compared with the IM group. This study demonstrated that the trabecular fibers immediately post-increased ICP (ONS dilation) were more porous than the control and remained statistically different (more porous) after 30 days. These results suggest a structural change that occurs in the ONS with elevations in ICP.

Determination of cerebral edema with serial measurement of optic nerve sheath diameter during treatment in children with diabetic ketoacidosis: a longitudinal study

Background Cerebral edema is a fatal complication that can occur in children with diabetic ketoacidosis (DKA). Its clinical signs are generally not explicit, and subclinical cerebral edema can occur. This study is one of the few longitudinal studies conducted to identify cerebral edema in patients with DKA by measuring the optic nerve sheath diameter (ONSD). The aim of this study was to investigate cerebral edema in children with DKA with serial measurement of ONSD, which is an early and reliable indicator of cerebral edema, and to monitor changes in ONSD during therapy. Methods The study was conducted by measuring ONSD ultrasonographically at baseline and during the course of therapy in patients with DKA. All participants were diagnosed and received therapy at our unit between May 2016 and June 2017. The study was registered with the Clinical Trials database, with a study number of NCT02937441. Measurements were obtained while the patients were in the supine position with their eyes closed, and axial transbulbar images of both eyes were obtained with a 6-15-MHz linear probe. Results The ONSD values of children with DKA changed during the treatment, reaching the highest values at 12-16 h of therapy, and the greatest ONSD was observed in children who had moderate and severe DKA. Conclusions During treatment of children with DKA, it is possible to predict cerebral edema by measuring ONSD, and this may contribute to clinical management, especially fluid treatment.

Dynamic assessment of cerebral blood flow and intracranial pressure during inversion table tilt using ultrasonography

CONTEXT

Inversion tables are used as treatment for back pain, but there is a lack of agreement on systemic effects of inversion.

OBJECTIVE

To assess intracranial pressure (ICP) and cerebral blood flow using ultrasonography during inversion table tilt.

METHODS

Optic nerve sheath diameter (ONSD), heart rate (HR), blood pressure, internal carotid artery (ICA) and middle cerebral artery (MCA) blood flow of participants were measured in 3 positions: supine before inversion, during inversion with head down, and supine post-inversion. ONSD was evaluated with ocular ultrasonography and blood flow (ICA and MCA) with Doppler ultrasonography.

RESULTS

The ONSD changed significantly between the supine position, at 3 min of inversion, and after returning to supine position (all P < .001). The post-inversion HR was less than pre-inversion (P = .03) and 3-min inversion HR (P = .003). There were significant changes in ICA and MCA flow caused by inversion, which affected blood flow velocity, resistance, and pulsatility index (all P ≤ .005).

CONCLUSION

Inversion caused significant changes in ICP and blood flow. Thus, increased chance of complications may exist when using inversion as a therapeutic tool or during surgical procedures in patients with previous history of elevated ICP. These results demonstrate that inversion therapy should be used with caution.

The Measurement of Elderly Volunteers' Optic Nerve Sheath Diameters by Ocular Ultrasonography

BACKGROUND AND OBJECTIVES

The optic nerve is a component of the central nervous system, and the optic nerve sheath is connected to the subarachnoid space. For this reason, intracranial pressure (ICP) increases are directly transmitted to the optic nerve sheath. Knowing the normal optic nerve sheath diameter (ONSD) range in a healthy population is necessary to interpret this measurement as a sign of intracranial pressure in clinical practice and research. In this study, we aimed to determine the standard ONSD value in healthy adultsaged65 years of age or older who had not previously been diagnosed with a disease that could increase the ICP.

MATERIALS AND METHODS

The right and left ONSD values and ONSD differences were compared, according to the gender of the patients. The patients were divided into 3 groups, according to their age. The age groups were assigned as follows: Group 1: 65-74 years of age; Group 2: 75-84 years of age; and Group 3: 85 years of age or older. The ONSDs and the ONSD difference between the left and right eyes of Group 1, Group 2 and Group 3 were compared.

RESULTS

The study included 195 volunteers. The mean ONSD of both eyes was 4.16±0.69 mm, and the difference between the ONSD of the left and right eyes was 0.16±0.18 mm. There was no difference between genders in terms of right ONSD, left ONSD, mean ONSD and ONSD difference between the left and right eyes. There was no correlation between age and ONSD and ONSD difference. When the age groups and ONSD were compared, no difference was found between the groups.

CONCLUSIONS

In conclusion, the ONSDs of both eyes do not vary with age in healthy adults aged65 years or older. ONSD does not vary between genders. The calculation of ONSD difference can be used to determine ICP increase.

Ultrasound measurements versus invasive intracranial pressure measurement method in patients with brain injury: a retrospective study

BACKGROUND

The invasive method for intracranial pressure measurement is 'gold standard' but not always feasible because the intraventricular catheter/ intraparenchymal micro transducer used in the measurement of intracranial pressure measurement may cause complications. Imaging modalities with clinical examination protocol have a lack of specificity and accuracy. The objective of the study was to compare the accuracy of diagnostic parameters of ultrasound measurements in patients with brain injury underwent invasive intracranial pressure measurement method.

METHODS

Data of invasive intracranial pressure measurement method and ultrasound measurements of 185 patients with brain injury who required admission diagnosis were included in the analysis. Pearson correlation was tested for diagnostic parameters. Logistical regression analysis was performed for diagnostic parameters of death patients to evaluate independent parameter of mortality.

RESULTS

Straight sinus flow velocities, middle cerebral artery flow velocities, and optic nerve sheath diameter were correlated with intracranial pressure (p < 0.0001 for all). Arterial blood pressure (p = 0.127) and middle cerebral artery pulsatility index (p = 0.06) were not correlated with intracranial pressure. A total of 47 patients died during the study period. Intracranial pressure (p = 0.015) and optic nerve sheath diameter (p = 0.035) were found to be independent predictor of mortality.

CONCLUSIONS

Ultrasound measurement especially optic nerve sheath diameter can be successfully used instead of invasive intracranial pressure measurement method in patients with brain injury.

LEVEL OF EVIDENCE

III.

Severe yellow fever in Brazil: clinical characteristics and management

BACKGROUND

Little is known about clinical characteristics and management of severe yellow fever as previous yellow fever epidemics often occurred in times or areas with little access to intensive care units (ICU). We aim to describe the clinical characteristics of severe yellow fever cases requiring admission to the ICU during the 2018 yellow fever outbreak in São Paulo, Brazil. Furthermore, we report on preliminary lessons learnt regarding clinical management of severe yellow fever.

METHODS

Retrospective descriptive cohort study. Demographic data, laboratory test results on admission, clinical follow-up, and clinical outcomes were evaluated.

RESULTS

From 10 January to 11 March 2018, 79 patients with laboratory confirmed yellow fever were admitted to the ICU in a tertiary hospital in Sao Paolo because of rapid clinical deterioration. On admission, the median AST was 7,000 IU/L, ALT 3,936 IU/L, total bilirubin 5.3 ml/dL, platelet 74 × 103/mm3, INR 2.24 and factor V 37%. Seizures occurred in 24% of patients, even without substantial intracranial hypertension. The high frequency of pancreatitis and rapidly progressive severe metabolic acidosis were notable findings. 73% of patients required renal replacement therapy. The in-hospital fatality rate was 67%. Patients with diabetes mellitus had a higher case fatality rate (CFR) of 80%, while patients without diabetes had a CFR of 65%. Leading causes of death were severe gastrointestinal bleeding, epileptic status, severe metabolic acidosis, necrohemorrhagic pancreatitis, and multi-organ failure.

CONCLUSIONS

Severe yellow fever is associated with a high CFR. The following management lessons were learnt: Anticonvulsant drugs in patients with any symptoms of hepatic encephalopathy or arterial ammonia levels >70 μmol/L was commenced which reduced the frequency of seizures from 28% to 17%. Other new therapy strategies included early institution of plasma exchange. Due to the high frequency of gastric bleeding, therapeutic doses of intravenous proton pump inhibitors should be administered.

Variability of optic nerve sheath diameter in acute ischemic stroke

Background:

Stroke is the third leading cause of death and the first cause of disability in the world. It holds an important place in hospital admissions and health expenses in the industrialized world.

Objective:

The aim of the study was to evaluate the relationship between optic nerve sheath diameter and the findings of brain computerized tomography scans and brain diffusion-weighted imaging and investigate the variability of optic nerve sheath diameter measured by ultrasonography in acute ischemic stroke.

Methods:

Patients who had acute ischemic stroke were included in Group A. Healthy adults were included in Group B as the control group. In addition, according to computerized tomography scans and diffusion-weighted imaging findings, Group A was divided into three subgroups. Patients with normal computerized tomography and diffusion-weighted imaging were included in Group 1, patients with normal computerized tomography and ischemic area on diffusion-weighted imaging were included in Group 2, and patients with ischemic area on computerized tomography and diffusion-weighted imaging were included in Group 3.

Results:

A total of 100 patients were included in Group A and 100 healthy adults included in Group B. The optic nerve sheath diameter values of Groups A and B were 5.4 ± 0.6 and 4.2 ± 0.4 mm (p < 0.001), respectively. The optic nerve sheath diameter cutoff value for detection of acute ischemic stroke was determined as 4.7 mm. The sensitivity and specificity at this cutoff value were determined as 89% and 90%, respectively. According to computerized tomography scans and diffusion-weighted imaging findings, there were 18 patients in Group 1, 56 patients in Group 2, and 26 patients in Group 3. Time from onset of symptoms to presentation to emergency department was shortest in Group 1 (3.0 ± 1.8 h). The widest optic nerve sheath diameter was calculated in Group 3 (optic nerve sheath diameter: 5.7 ± 0.6 mm).

Conclusion:

This study demonstrates that the optic nerve sheath diameter increases in acute ischemic stroke and it increases earlier than computerized tomography and diffusion-weighted imaging alteration occur. Therefore, optic nerve sheath diameter can be applied to assist the diagnosis of acute ischemic stroke with other imaging techniques with equivocal/negative results and determination of appropriate treatment, especially in cases with normal computerized tomography scan and diffusion-weighted imaging.

The Influence of Cervical Collar Immobilization on Optic Nerve Sheath Diameter

BACKGROUND

Prior research has revealed that cervical collars elevate intracranial pressure (ICP) in patients with traumatic brain injury. Two recent small studies evaluated the change in optic sheath nerve diameter (ONSD) measured by ultrasound as a proxy for ICP following cervical collar placement in healthy volunteers.

OBJECTIVE

We sought to validate the finding that ONSD measured by ultrasound increases after cervical collar placement within an independent data set.

METHODS

This was a prospective, crossover study involving volunteers. Participants were randomized to either have the ONSD measured first without a cervical collar or initially with a cervical collar. Two sonographers performed independent ONSD diameter measurements. Continuous data were analyzed by matched-paired t-tests. Alpha was set at 0.05. The primary outcome parameter was the overall mean difference between ONSD measurements with the cervical collar on and off. Multiple linear regression was performed to examine the relationship between variables and the primary outcome parameter.

RESULTS

There were 30 participants enrolled in the study. Overall mean ONSD for participants without the collar was 0.365 ± 0.071 cm and with the collar was 0.392 ± 0.081 cm. The mean change in ONSD for participants with and without the collar was 0.026 ± 0.064 cm (95% confidence interval of difference: 0.015-0.038; P < 0.001). Multiple regression analysis did not identify any variables associated with the variation in ONSD observed for collar versus noncollar.

CONCLUSIONS

We confirmed that ONSD does vary by a measurable amount with placement of a rigid cervical collar on healthy volunteers when assessed by ultrasound.

Measurement of changes in optic nerve sheath diameter using ultrasound and computed tomography scan before and after the ventriculoperitoneal shunt surgery in patients with hydrocephalus - A prospective observational trial

BACKGROUND

The standard methods for measuring intracranial pressure (ICP) are invasive in nature. Non invasive methods such as ONSD may help circumvent these complications and may serve as a surrogate marker for increased ICP. The primary aim of this study was to assess the ONSD (optic nerve sheath diameter) changes using ultrasonography (USG) and computed tomography (CT) scan in hydrocephalus patients before and after the insertion of VP shunt.

MATERIALS AND METHODS

A prospective observational study was conducted among 69 patients undergoing VP shunt surgery between the ages of 2 to 60 years. ONSD variation was measured by USG and CT scan both before and after the surgery. The difference in the pre-operative and post-operative ONSD measurement was analyzed using a paired t-test. Whereas, the measurements of ONSD were compared for agreement between two modalities (USG and CT) using Interclass correlation (ICC) and Bland Altman graph plot.

RESULTS

Among 69 patients 38 were males, 31 were females and 12 were under the age of 10 years. In the adult group, average preoperative and postoperative ONSD measurement by USG was 5.80 ± 0.63 mm and 4.52 ± 0.72 (p < 0.001) and by CT was 5.77 ± 0.83 mm and 4.49 ± 0.76 mm (p < 0.001) respectively. Similarly, in the pediatric population, average preoperative and postoperative ONSD measurement by USG was found to be 4.76 ± 1.14 mm and 3.90 ± 1.08 mm and by CT was found to be 4.75+/-1.11 mm and 3.85 ± 1.09 mm respectively (p <0.001).

CONCLUSION

In patients with hydrocephalus undergoing VP shunt surgery, we found a significant reduction in ONSD after the shunt insertion in both pediatric and adult population. We also found a good correlation between the USG and CT scan measurements of ONSD.

Ultrasonic Assessment of Optic Nerve Sheath to Detect Increased Intracranial Pressure

Purpose

Increased intracranial pressure (ICP) is one of the prevalent symptoms of trauma, especially traumatic headache, which requires quick action for the diagnosis and treatment. The optic nerve sheath diameter (ONSD) is a newly proposed technique for the detection of an increase in ICP. The aim of this study was to assess the efficacy of this new diagnostic method in patients with increased ICP induced by trauma.

Methods

This prospective study was conducted between December 2016 and February 2017. The patients with traumatic headache and who had been diagnosed with increased ICP using clinical signs and computed tomography scan were compared to the voluntary healthy group. In each patient, measurements were performed employing ultrasound three times on each eye in an axial region, and the mean of these sizes was obtained as the ONSD.

Results

A total of 112 participants were examined. The mean ONSD measurement of the patients and the voluntary healthy group was 6.01 ± 0.76 and 3.41 ± 0.56 mm in the right eye, 6.11 ± 0.75 and 3.39 ± 0.54 mm in the left eye, and 6.06 ± 0.75 and 4.02 ± 1.07 mm in both sides, respectively. The ONSD in the right and left sides had high and significant correlation in the patients (r = 0.929, P < 0.000) and voluntary healthy (r = 0.630, P < 0.000) group. The mean ONSD of one of the patients was 6.24 ± 0.56 mm, and in another patient with no clinical sign of increased ICP, the mean ONSD was 4.61 ± 0.09 mm.

Conclusions

Ultrasound performed on the diaphragm of the optic nerve with acceptable sensitivity can detect patients with an increase in ICP and can be efficacious in expediting the action needed to reduce ICP. Due to the sensitivity and specificity of the ultrasound and high accuracy of the diameter of optic nerve sheath in detecting increase in ICP, as well as considering the fact that ultrasound is a noninvasive and available technique; it can be performed at the patient's bedside.

Ocular Ultrasonography: A Useful Instrument in Patients with Trauma Brain Injury in Emergency Service

The measurement of the optic nerve sheath by ocular ultrasonography might be an indirect method to assess the quickly increase of the intracranial pressure in patients with moderate trauma brain injury, taking into account that an important proportion of these could develop the increase of the intracranial pressure in a hospital-acquired way. Therefore noninvasive, reliable, and convenient techniques are needed making the ocular ultrasonography a useful tool, due to the invasive monitoring elements' problems and the poor access to measure the intracranial pressure in emergency services. In spite of the limitations and few studies that exist to consider it as a possible early detection, this technique could work as a noninvasive one in the case that could not be possible to do invasive monitoring or when it is not recommended.

Association of optic nerve sheath diameter measurement with hyponatremia in emergency department

OBJECTIVE

Investigation of association of ONSD with hyponatremia in symptomatic patients.

METHODS

89 patients who were diagnosed to have hyponatremia (Na + <135 mmol/L) were prospectively analyzed and compared with 72 patients who have normal serum sodium levels presented to ED at the same time interval. Subjects' demographic properties including age and sex were recorded, as were admission symptoms, serum Na + level, and pre-treatment and post-treatment optic nerve sheath diameter (ONSD).

RESULTS

The mean age of the study population was 62.3 ± 17.6 years, and the control group 55.1 ± 20.0 years (p < 0.05). There was a significant difference between the patient group's pre-treatment and post-treatment OSNDs compared to the controls (p < 0.05). There was a significant negative correlation between the admission sodium level and ONSD in the patient group (p < 0.05). In the pre-treatment period, patients with symptoms had a significantly greater mean ONSD than those without symptoms (0.546 ± 0.068 mm vs 0.448 ± 0.081 mm; p < 0.05). The area under the curve was 0.870; the cut-off level calculated for hyponatremia was 0.49 mm, which had a sensitivity of 81% and a specificity of 81.9%.

CONCLUSION

Ultrasonic imaging of ONSD measurement in the emergency department appears to reflect changes consistent with ICP changes in hyponatremia and change in serum sodium.

Is initial optic nerve sheath diameter prognostic of specific head injury in emergency departments?

BACKGROUND

Emergency departments (EDs) are typically the first medical contact for patients with traumatic brain injury (TBI) and early diagnosis and treatment of intracranial pressure (ICP) in patients with neurotrauma primarily falls under the liability of emergency doctors. Monitoring ICP with optic nerve sheath diameter (ONSD) via tools has gained popularity among emergency service doctors. In this study, we aimed to evaluate the predictive value of ONSD for specific head injury on initial cranial tomography.

METHODS

CT scans of 176 patients with a known intracranial pathology were retrospectively analyzed and compared with normal control CTs of 182 patients presented to ED at the same time interval. The attending radiologist analyzed all initial brain CT scans and randomly sampled control CTs were similarly assessed by the second senior radiologist whom were blind to the patients' medical histories and circumstances of TBI at the time of measurement. ONSD was measured at a distance of 3 mm behind the eyeball, immediately below the sclera.

RESULTS

Right ONSD value was significantly higher in patients with herniation and SAH (p = 0,024 and 0,028, respectively). Left ONSD values was at the level of statistical significance and mean ONSD values was significantly higher in patients with SAH (p = 0.05 and 0.026, respectively). Right-left-mean ONSD values were statistically higher in study group with bilateral lesions on brain CT (p < 0,001). ONSD measurements and patient age were higher in patients who died (p < 0,001).

CONCLUSIONS

ONSD measurement on initial brain CT is lesion dependent and indicates mortality.

Comparison of ultrasonography and computed tomography in the determination of traumatic thoracic injuries

OBJECTIVE

In this study, the accuracy of bedside thoracic ultrasonography (TUSG) performed by emergency physicians with patients in the supine position was compared with that of thoracic computed tomography (TCT) for the determination of thoracic injuries due to trauma.

METHODS

Patients who suffered the multiple traumas, whose thoracic trauma was identified on physical examination or TCT imaging were included in the study. TUSG was performed following a physical examination by the emergency physician who managed the trauma patient. Subcutaneous emphysema, pneumothorax, pulmonary contusions (PCs), hemothorax, pericardial effusion and tamponade, sternal and clavicular fractures and rib fractures were identified by TUSG. TCT imaging was performed after the ultrasonography examination was completed.

RESULTS

Eighty-one patients were included in the study. TCT scans showed subcutaneous emphysema in 16 (19.8%) patients, pneumothorax in 21 (25.9%), PCs in 27 (33.3%), hemothorax in 20 (24.7%), sternum and clavicular fractures in 6 (7.4%) and rib fractures in 21 (25.9%). The sensitivity and specificity of ultrasonography varied for detecting the following pathologies: subcutaneous emphysema (56% and 95%), pneumothorax (86% and 97%), hemothorax (45% and 98%), PCs (63% and 91%), sternal fractures (83% and 97%), clavicular fractures (83% and 100%) and rib fractures (67% and 98%), respectively.

CONCLUSION

In conclusion, ultrasound was found to be highly specific but only moderately sensitive for the identification of thoracic injuries.

Adjunctive dexamethasone for the treatment of HIV-infected adults with tuberculous meningitis (ACT HIV): Study protocol for a randomised controlled trial

Background: Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Co-infection with HIV increases the risk of developing TBM, complicates treatment, and substantially worsens outcome. Whether corticosteroids confer a survival benefit in HIV-infected patients with TBM remains uncertain. Hepatitis is the most common drug-induced serious adverse event associated with anti-tuberculosis treatment, occurring in 20% of HIV-infected patients. The suggested concentration thresholds for stopping anti-tuberculosis drugs are not evidence-based. This study aims to determine whether dexamethasone is a safe and effective addition to the first 6-8 weeks of anti-tuberculosis treatment of TBM in patients with HIV, and investigate alternative management strategies in a subset of patients who develop drug induced liver injury (DILI) that will enable the safe continuation of rifampicin and isoniazid therapy.  Methods: We will perform a parallel group, randomised (1:1), double blind, placebo-controlled multi-centre Phase III trial, comparing the effect of dexamethasone versus placebo on overall survival in HIV-infected patients with TBM, in addition to standard anti-tuberculosis and antiretroviral treatment. The trial will be set in two hospitals in Ho Chi Minh City, Vietnam, and two hospitals in Jakarta, Indonesia. The trial will enrol 520 HIV-infected adults. An ancillary study will perform a randomised comparison of three DILI management strategies with the aim of demonstrating which strategy results in the least interruption in rifampicin and isoniazid treatment. An identical ancillary study will also be performed in the linked randomised controlled trial of dexamethasone in HIV-uninfected adults with TBM stratified by LTA4H genotype (LAST ACT).  Discussion: Whether corticosteroids confer a survival benefit in HIV-infected patients remains uncertain, and the current evidence base for using corticosteroids in this context is limited. Interruptions in anti-tuberculosis chemotherapy is a risk factor for death from TBM. Alternative management strategies in DILI may allow the safe continuation of rifampicin and isoniazid therapy.

Novel minimally invasive multi-modality monitoring modalities in neurocritical care

Elevated intracranial pressure (ICP) following brain injury contributes to poor outcomes for patients, primarily by reducing the caliber of cerebral vasculature, and thereby reducing cerebral blood flow. Careful monitoring of ICP is critical in these patients in order to determine prognosis, implement treatment when ICP becomes elevated, and to judge responsiveness to treatment. Currently, the gold standard for monitoring is invasive pressure transducers, usually an intraventricular monitor, which presents significant risk of infection and hemorrhage. These risks made discovering non-invasive methods for monitoring ICP and cerebral perfusion a priority for researchers. Herein we sought to review recent publications on novel minimally invasive multi-modality monitoring techniques that provide surrogate data on ICP, cerebral oxygenation, metabolism and blood flow. While limitations in various forms preclude them from supplanting the use of invasive monitors, these modalities represent useful screening tools within our armamentarium that may be invaluable when the risks of invasive monitoring outweigh the associated benefits.

Adjunctive dexamethasone for the treatment of HIV-infected adults with tuberculous meningitis (ACT HIV): Study protocol for a randomised controlled trial

Background: Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Co-infection with HIV increases the risk of developing TBM, complicates treatment, and substantially worsens outcome. Whether corticosteroids confer a survival benefit in HIV-infected patients with TBM remains uncertain. Hepatitis is the most common drug-induced serious adverse event associated with anti-tuberculosis treatment, occurring in 20% of HIV-infected patients. The suggested concentration thresholds for stopping anti-tuberculosis drugs are not evidence-based. This study aims to determine whether dexamethasone is a safe and effective addition to the first 6-8 weeks of anti-tuberculosis treatment of TBM in patients with HIV, and investigate alternative management strategies in a subset of patients who develop drug induced liver injury (DILI) that will enable the safe continuation of rifampicin and isoniazid therapy.  Methods: We will perform a parallel group, randomised (1:1), double blind, placebo-controlled multi-centre Phase III trial, comparing the effect of dexamethasone versus placebo on overall survival in HIV-infected patients with TBM, in addition to standard anti-tuberculosis and antiretroviral treatment. The trial will be set in two hospitals in Ho Chi Minh City, Vietnam, and two hospitals in Jakarta, Indonesia. The trial will enrol 520 HIV-infected adults. An ancillary study will perform a randomised comparison of three DILI management strategies with the aim of demonstrating which strategy results in the least interruption in rifampicin and isoniazid treatment. An identical ancillary study will also be performed in the linked randomised controlled trial of dexamethasone in HIV-uninfected adults with TBM stratified by LTA4H genotype (LAST ACT).  Discussion: Whether corticosteroids confer a survival benefit in HIV-infected patients remains uncertain, and the current evidence base for using corticosteroids in this context is limited. Interruptions in anti-tuberculosis chemotherapy is a risk factor for death from TBM. Alternative management strategies in DILI may allow the safe continuation of rifampicin and isoniazid therapy.

Adjunctive dexamethasone for the treatment of HIV-uninfected adults with tuberculous meningitis stratified by Leukotriene A4 hydrolase genotype (LAST ACT): Study protocol for a randomised double blind placebo controlled non-inferiority trial

Background: Tuberculosis kills more people than any other bacterial infection worldwide. In tuberculous meningitis (TBM), a common functional promoter variant (C/T transition) in the gene encoding leukotriene A4 hydrolase (LTA4H), predicts pre-treatment inflammatory phenotype and response to dexamethasone in HIV-uninfected individuals. The primary aim of this study is to determine whether LTA4H genotype determines benefit or harm from adjunctive dexamethasone in HIV-uninfected Vietnamese adults with TBM. The secondary aim is to investigate alternative management strategies in individuals who develop drug induced liver injury (DILI) that will enable the safe continuation of rifampicin and isoniazid therapy.  Methods: We will perform a parallel group, randomised (1:1), double blind, placebo-controlled,  multi-centre Phase III non-inferiority trial, comparing dexamethasone versus placebo for 6-8 weeks in addition to standard anti-tuberculosis treatment in HIV-uninfected patients with TBM stratified by LTA4H genotype. The primary endpoint will be death or new neurological event. The trial will enrol approximately 720 HIV-uninfected adults with a clinical diagnosis of TBM, from two hospitals in Ho Chi Minh City, Vietnam. 640 participants with CC or CT- LTA4H genotype will be randomised to either dexamethasone or placebo, and the remaining TT- genotype participants will be treated with standard-of-care dexamethasone. We will also perform a randomised comparison of three management strategies for anti-tuberculosis DILI. An identical ancillary study will also be perfomed in the linked randomised controlled trial of dexamethasone in HIV-infected adults with TBM (ACT HIV).  Discussion: Previous data have shown that LTA4H genotype may be a critical determinant of inflammation and consequently of adjunctive anti-inflammatory treatment response in TBM. We will stratify dexamethasone therapy according to LTA4H genotype in HIV-uninfected adults, which may indicate a role for targeted anti-inflammatory therapy according to variation in LTA4H C/T transition. A comparison of DILI management strategies may allow the safe continuation of rifampicin and isoniazid.

Effect of History of Mild Traumatic Brain Injury on Optic Nerve Sheath Diameter Changes after Valsalva Maneuver

Optic nerve sheath diameter (ONSD) measured by transocular ultrasound is a marker of real-time intracranial pressure (ICP). The objective of this study was to evaluate the association between optic nerve sheath (ONS) dilation after a Valsalva maneuver and a prior history of mild to moderate traumatic brain injury (mTBI) in a heterogeneous sample of participants. Participants were excluded if they had had a recent brain injury, were symptomatic from a prior brain injury, had a history consistent with severe TBI and/or had undergone intracranial surgery. Ninety-five participants with and without a history of mTBI were included in the study. Transocular ultrasound of the ONS was performed before and after a Valsalva maneuver. Differences in the ONSD before and after a Valsalva maneuver were analyzed and correlated to the participants' history of mTBI. Baseline ONSD measurements between groups were not statistically significant. Following Valsalva, participants with a history of mTBI had a statistically significant increase in the ONSD compared with participants with no history of mTBI. This significant difference persisted after controlling for age, race, and sex. This study demonstrated an association between a prior history of mTBI and dilation of the ONS after Valsalva maneuver in a sample of asymptomatic participants, which was not seen in participants without a history of mTBI.

Correlation of optic nerve sheath diameter with directly measured intracranial pressure in Korean adults using bedside ultrasonography

Objectives

The correlation of optic nerve sheath diameter (ONSD) as seen on ultrasonography (US) and directly measured intracranial pressure (ICP) has been well described. Nevertheless, differences in ethnicity and type of ICP monitor used are obstacles to the interpretation. Therefore, we investigated the direct correlation between ONSD and ventricular ICP and defined an optimal cut-off point for identifying increased ICP (IICP) in Korean adults with brain lesions.

Methods

This prospective study included patients who required an external ventricular drainage (EVD) catheter for ICP control. IICP was defined as an opening pressure over 20 mmHg. ONSD was measured using a 13 MHz US probe before the procedure. Linear regression analysis and receiver operator characteristic (ROC) curve were used to assess the association between ONSD and ICP. Optimal cut-off value for identifying IICP was defined.

Results

A total of 62 patients who underwent ONSD measurement with simultaneous EVD catheter placement were enrolled in this study. Thirty-two patients (51.6%) were found to have IICP. ONSD in patients with IICP (5.80 ± 0.45 mm) was significantly higher than in those without IICP (5.30 ± 0.61 mm) (P < 0.01). The IICP group showed more significant linear correlation with ONSD (r = 0.57, P < 0.01) compared to the non-IICP group (r = 0.42, P = 0.02). ONSD > 5.6 mm disclosed a sensitivity of 93.75% and a specificity of 86.67% for identifying IICP.

Conclusion

ONSD as seen on bedside US correlated well with directly measured ICP in Korean adults with brain lesions. The optimal cut-off point of ONSD for detecting IICP was 5.6 mm.

High-resolution transbulbar ultrasonography helping differentiate intracranial hypertension in bilateral optic disc oedema patients

PURPOSE

The enlargement of optic nerve sheath diameter (ONSD) has been proven to be related with raised intracranial pressure (ICP). No prospective study has been focused on utilizing retrobulbar ultrasonography in optic disc oedema patient presented to ophthalmologist.

METHODS

High-resolution transbulbar ultrasonography was performed in a cohort of patient presented with bilateral optic disc oedema. The subarachnoid space of optic nerve (SAS), ONSD and optic nerve diameter (OND) was measured prior to other ancillaries including lumbar puncture. Subjects were classified into increased intracranial pressure (IIP) and normal intracranial pressure (NIP) group according to the open cerebrospinal fluid pressure more than 200 mm H₂ 0. The SAS, ONSD and OND were compared between groups and with normal control. The sensitivity of SAS or ONSD change for predicating intracranial hypertension was assessed.

RESULTS

A total of 20 IIP, 25 NIP patients and 25 normal controls were evaluated. The mean SAS and ONSD measured in idiopathic intracranial hypertension group was significantly increased than that of NIP and controls (p < 0.001), whereas the OND showed no statistic difference between each group. The sensitivities using the SAS and ONSD for differentiating increased ICP in optic disc oedema patients were 0.99 and 0.97, respectively.

CONCLUSIONS

The enlarged SAS and ONSD measured by high-resolution transbulbar sonography are very sensitive parameters to predicate increased ICP in bilateral optic disc oedema patients.

Ultrasound non-invasive measurement of intracranial pressure in neurointensive care: A prospective observational study

BACKGROUND

The invasive nature of the current methods for monitoring of intracranial pressure (ICP) has prevented their use in many clinical situations. Several attempts have been made to develop methods to monitor ICP non-invasively. The aim of this study is to assess the relationship between ultrasound-based non-invasive ICP (nICP) and invasive ICP measurement in neurocritical care patients.

METHODS AND FINDINGS

This was a prospective, single-cohort observational study of patients admitted to a tertiary neurocritical care unit. Patients with brain injury requiring invasive ICP monitoring were considered for inclusion. nICP was assessed using optic nerve sheath diameter (ONSD), venous transcranial Doppler (vTCD) of straight sinus systolic flow velocity (FVsv), and methods derived from arterial transcranial Doppler (aTCD) on the middle cerebral artery (MCA): MCA pulsatility index (PIa) and an estimator based on diastolic flow velocity (FVd). A total of 445 ultrasound examinations from 64 patients performed from 1 January to 1 November 2016 were included. The median age of the patients was 53 years (range 37-64). Median Glasgow Coma Scale at admission was 7 (range 3-14), and median Glasgow Outcome Scale was 3 (range 1-5). The mortality rate was 20%. ONSD and FVsv demonstrated the strongest correlation with ICP (R = 0.76 for ONSD versus ICP; R = 0.72 for FVsv versus ICP), whereas PIa and the estimator based on FVd did not correlate with ICP significantly. Combining the 2 strongest nICP predictors (ONSD and FVsv) resulted in an even stronger correlation with ICP (R = 0.80). The ability to detect intracranial hypertension (ICP ≥ 20 mm Hg) was highest for ONSD (area under the curve [AUC] 0.91, 95% CI 0.88-0.95). The combination of ONSD and FVsv methods showed a statistically significant improvement of AUC values compared with the ONSD method alone (0.93, 95% CI 0.90-0.97, p = 0.01). Major limitations are the heterogeneity and small number of patients included in this study, the need for specialised training to perform and interpret the ultrasound tests, and the variability in performance among different ultrasound operators.

CONCLUSIONS

Of the studied ultrasound nICP methods, ONSD is the best estimator of ICP. The novel combination of ONSD ultrasonography and vTCD of the straight sinus is a promising and easily available technique for identifying critically ill patients with intracranial hypertension.

The comparison of point-of-care ultrasonography and radiography in the diagnosis of tibia and fibula fractures

OBJECTIVE

We aimed to compare the efficacy of Point-of-care ultrasonography (POCUS) with radiography in the diagnosis of tibia fracture (TF) and fibula fracture (FF), and determation of fracture characteristics.

METHODS

Patients aged 5-55 years who were admitted to ED due to low-energy, simple extremity trauma, who had a suspected TF and FF on physical examination were included in this prospective study. One physician performed POCUS examination. Other physician evaluated the radiography images. The obtained results were compared.

RESULTS

A total of 62 patients were included in the study. TF was detected in 21 patients by radiography and in 24 patients by POCUS. FF was detected in 24 patients by radiography and in 25 patients by POCUS. Ten of the patients had both TF and FF. Compared with radiography, sensitivity, specificity, PPV and NPV of POCUS in the detection of TF were 100%, 93%, 88% and 100% (95% CI, 91-100%), respectively. Compared with direct X-ray imaging, sensitivity, specificity, PPV and NPV of POCUS in the detection of FF were 100%, 97%, 96% and 100% (95% CI, 96-100%), respectively. We determined that POCUS is also successful in detection of fracture features such as angulation, step-off, extension into the joint space that can determine the treatment decision.

CONCLUSION

This study demonstrated that POCUS was found to be as successful as direct X-ray imaging in the diagnosis of TF and FF.

The comparison of radiography and point-of-care ultrasonography in the diagnosis and management of metatarsal fractures

OBJECTIVE

It was aimed to compare the efficacy of point-of-care ultrasonography (POCUS) with radiography in the diagnosis and management of metatarsal fracture (MTF).

METHODS

Patients aged 5-55 years admitted to emergency room due to low-energy, simple extremity trauma and had a suspected MTF, were included in this prospective study. Patients were evaluated by two different emergency physicians in the emergency room. The first physician performed POCUS examination. Second physician evaluated the radiography images. The obtained results were compared.

RESULTS

Seventy-two patients were enrolled in the study. Fracture was detected in 39% by radiography and in 43% of patients by POCUS. Multiple MTFs were identified in 5% of patients. Compared with radiography, POCUS had a sensitivity of 93%, specificity of 89%, positive predictive value of 84% and a negative predictive value of 95% (95% CI, 83-98%) in the detection of fractures. While soft tissue edema was seen in 61% of patients by POCUS, soft tissue edema with hematoma was detected in 14%. Compared with radiography, the sensitivity and specificity of POCUS in the decision for surgery were 100% and 98% (95% CI, 97-100%), respectively, whereas its sensitivity and specificity were both 100% in the decision for reduction.

CONCLUSION

In our study, we demonstrated that POCUS could be applied with success in the diagnosis and treatment of MTF in low-energy injuries. POCUS can be used as an alternative to radiography in the emergency rooms due to being easy to learn and practice and availability of soft tissue examination along with bone tissue examination.

The incidence of increased ICP in ICU patients with non-traumatic coma as diagnosed by ONSD and CT: a prospective cohort study

BACKGROUND

Unexplained coma after critical illness can be multifactorial. We evaluated the diagnostic ability of bedside Optic Nerve Sheath Diameter [ONSD] as a screening test for non-traumatic radiographic cerebral edema.

METHODS

In a prospective study, mixed medical-surgical intensive care units [ICU] patients with non-traumatic coma [GCS < 9] underwent bedside ultrasonographic ONSD measurements. Non-traumatic radiographic cerebral edema [NTRCE] was defined as > 5 mm midline shift, cisternal, sulcal effacement, or hydrocephalus on CT.

RESULTS

NTRCE was identified in 31 of 102 patients [30.4 %]. The area under the ROC curve for detecting radiographic edema by ONSD was 0.785 [95 % CI 0.695-0.874, p <0.001]. ONSD diameter of 0.57 cm was found to be the best cutoff threshold with a sensitivity 84 % and specificity 71 %, AUC 0.785 [95 % CI 0.695-0.874, p <0.001]. Using ONSD as a bedside test increased the post-test odds ratio [OR] for NTRCE by 2.89 times [positive likelihood ratio], whereas post-test OR for NTRCE decreased markedly given a negative ONSD test [ONSD measurement less than 0.57 cm]; negative likelihood ratio 0.22.

CONCLUSIONS

The use of ONSD as a bedside test in patients with non-traumatic coma has diagnostic value in identifying patients with non-traumatic radiographic cerebral edema.