Elevated Intracranial Pressure Diagnosis with Emergency Department Bedside Ocular Ultrasound

Diagnostic Accuracy of Ocular Ultrasonography in Identifying Raised Intracranial Pressure among Pediatric Population

INTRODUCTION

Role of CT scan, MRI, ophthalmoscopy, direct monitoring by a transducer probe in identifying raised intracranial pressure (ICP) in emergency department is limited. There are few studies correlating elevated optic nerve sheath diameter (ONSD) measured by point of care ultrasound (POCUS) with raised ICP in pediatrics emergencies. We studied the diagnostic accuracy of ONSD, crescent sign, and optic disc elevation in identifying increased ICP in pediatrics.

METHODS

Prospective observational study was done between April 2018 and August 2019 after ethics approval. Out of 125 subjects, 40 patients without clinical features of raised ICP were recruited as external controls and 85 with clinical features of raised ICP as study subjects. Their demographic profile, clinical examination, and ocular ultrasound findings were noted. This was followed by CT scan. Out of 85 patients, 43 had raised ICP (cases) and 42 had normal ICP (disease controls). Diagnostic accuracy of ONSD in identifying raised ICP was evaluated using STATA.

RESULTS

The mean ONSD in case group was 5.5 ± 0.6 mm, 4.9 ± 0.5 mm in disease control group and external control group was 4.8 ± 0.3 mm. Cut-off of ONSD for raised ICP at ≥4.5 mm had a sensitivity and specificity of 97.67% and 10.98%, while ≥5.0 mm showed a sensitivity and specificity of 86.05% and 71.95%. Crescent sign and optic disc elevation had good correlation with increased ICP.

CONCLUSION

ONSD ≥5 mm by POCUS identified raised ICP in pediatric population. Crescent sign and optic disc elevation may function as additional POCUS signs in identifying raised ICP.

Value of Optic Nerve Sheath Diameter in Diagnosis and Follow Up of Patients with Disturbed Conscious Level

Background

Ultrasonographic measurement of optic nerve sheath diameter is a simple, non-invasive, and reliable method of detecting elevated intracranial pressure (ICP) in critical patients. Optic nerve sheath communicates with the dura mater covering the brain and contains cerebrospinal fluid, allowing pressure transmission from the cranium. Therefore, changes in cerebrospinal fluid (CSF) pressure have been shown to produce changes in ONSD.

Objective

This study aimed to assess the accuracy of optic nerve sheath diameter (ONSD) in diagnosis and follow-up patients with disturbed conscious levels compared with CT brain and fundus examination.

Patients and Methods

One hundred forty-one participants were included in the study, classified into 76 cases admitted with disturbed conscious levels due to elevated ICP and 65 controls. All patients were subjected to CT brain and optic nerve US and fundus examination at the time of admission and follow-up after 48 h after proper management.

Results

The current study showed that ONSD is significant in predicting elevated ICP at the cut-off point of average ONSD of 5.19 mm with 97% sensitivity and 98% specificity, and the area under the curve (AUC) was 0.996. The present study revealed a significant inverse correlation between ONSD and GCS in patients with increased ICP.

Conclusion

Ultrasonic measurement of ONSD is a promising technique in diagnosing and following patients with disturbed conscious levels.

Optic Nerve Sheath Diameter Ultrasound for Raised Intracranial Pressure: A Literature Review and Meta-analysis of its Diagnostic Accuracy

Optic nerve sheath diameter (ONSD) ultrasound is becoming increasingly more popular for estimating raised intracranial pressure (ICP). We performed a systematic review and analysis of the diagnostic accuracy of ONSD when compared to the standard invasive ICP measurement.

METHOD

We performed a systematic search of PUBMED and EMBASE for studies including adult patients with suspected elevated ICP and comparing sonographic ONSD measurement to a standard invasive method. Quality of studies was assessed using the QUADAS-2 tool by two independent authors. We used a bivariate model of random effects to summarize pooled sensitivity, specificity, and diagnostic odds ratio (DOR). Heterogeneity was investigated by meta-regression and sub-group analyses.

RESULTS

We included 18 prospective studies (16 studies including 619 patients for primary outcome). Only one study was of low quality, and there was no apparent publication bias. Pooled sensitivity was 0.9 [95% confidence intervals (CI): 0.85-0.94], specificity was 0.85 (95% CI: 0.8-0.89), and DOR was 46.7 (95% CI: 26.2-83.2) with partial evidence of heterogeneity. The Area-Under-the-Curve of the summary Receiver-Operator-Curve was 0.93 (95% CI: 0.91-0.95, P < .05). No covariates were significant in the meta-regression. Subgroup analysis of severe traumatic brain injury and parenchymal ICP found no heterogeneity. ICP and ONSD had a correlation coefficient of 0.7 (95% CI: 0.63-0.76, P < .05).

CONCLUSION

ONSD is a useful adjunct in ICP evaluation but is currently not a replacement for invasive methods where they are feasible.

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.

Pulsatile Dynamics of the Optic Nerve Sheath and Intracranial Pressure: An Exploratory In Vivo Investigation

BACKGROUND

Raised intracranial pressure (ICP) may lead to increased stiffness of the optic nerve sheath (ONS).

OBJECTIVE

To develop a method for analyzing ONS dynamics from transorbital ultrasound and investigate a potential difference between patients with raised ICP vs normal ICP.

METHODS

We retrospectively analyzed data from 16 patients (≤12 years old) for whom ultrasound image sequences of the ONS had been acquired from both eyes just before invasive measurement of ICP. Eight patients had an ICP ≥20 mm Hg. The transverse motion on each side of the ONS was estimated from ultrasound, and Fourier analysis was used to extract the magnitude of the displacement corresponding to the heart rate. By calculating the normalized absolute difference between the displacements on each side of the ONS, a measure of ONS deformation was obtained. This parameter was referred to as the deformability index. According to our hypothesis, because deformability is inversely related to stiffness, we expected this parameter to be lower for ICP ≥20 mm Hg compared with ICP <20 mm Hg. The one-sided Mann-Whitney U test was used for statistical comparison.

RESULTS

The deformability index was significantly lower in the group with ICP ≥20 mm Hg (median value 0.11 vs 0.24; P = .002).

CONCLUSION

We present a method for assessment of ONS pulsatile dynamics using transorbital ultrasound imaging. A significant difference was noted between the patient groups, indicating that deformability of the ONS may be relevant as a noninvasive marker of raised ICP. The clinical implications are promising and should be investigated in future clinical studies.

ABBREVIATIONS

AUC, area under curveICP, intracranial pressureONS, optic nerve sheathONSD, optic nerve sheath diameterROC, receiver operating characteristic.

Optic nerve sheath diameter sonography for the diagnosis of increased intracranial pressure: a systematic review and meta-analysis protocol

INTRODUCTION

Increased intracranial pressure (ICP) is a significant neurological issue that may lead to permanent neurological sequelae. When evaluating patients with traumatic brain injury, it is crucial to identify those with high ICP in order to expedite ICP lowering measures and maintain adequate cerebral perfusion. Several measures are used to recognise patients with increased ICP including CT scan, MRI, ICP monitor, and lumbar puncture (LP). However, these tests can be invasive, associated with radiation exposure, contraindicated, or not readily available. Ultrasonography measurement of the optic nerve sheath diameter (ONSD) is proposed as a non-invasive and quick measure to identify high ICP. The aim of this systematic review and meta-analysis will be to examine the accuracy of ONSD sonography for increased ICP diagnosis.

METHODS AND ANALYSES

We will include published and unpublished randomised controlled trials, observational studies, and abstracts, with no publication type or language restrictions. Search strategies will be designed to peruse the MEDLINE, Embase, Web of Science, WHO Clinical Trials, ClinicalTrials.gov, CINAHL, and the Cochrane Library databases. We will also implement strategies to search grey literature. Two reviewers will independently complete data abstraction and conduct quality assessment. Included studies will be assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. We will construct the hierarchical summary receiver operating characteristic curve for included studies and pool sensitivity and specificity using the bivariate model. We also plan to conduct prespecified subgroup analyses to explore heterogeneity. The overall quality of evidence will be rated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE).

ETHICS AND DISSEMINATION

Research ethics board approval is not required for this study as it draws from published data and raises no concerns related to patient privacy. This review will provide a comprehensive assessment of the evidence on ONSD sonography diagnostic accuracy and is directed to a wide audience. Results from the review will be disseminated extensively through conferences and submitted to a peer-reviewed journal for publication.

PROSPERO REGISTRATION NUMBER

CRD42017055485.

CLINICAL TRIAL NUMBER

Trial registration number is NCT00783809.

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.