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Marzola F, Lochner P, Naldi A, Lemor R, Stögbauer J, Meiburger KM. Development of a Deep Learning-Based System for Optic Nerve Characterization in Transorbital Ultrasound Images on a Multicenter Data Set. ULTRASOUND IN MEDICINE & BIOLOGY 2023:S0301-5629(23)00169-2. [PMID: 37357081 DOI: 10.1016/j.ultrasmedbio.2023.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 05/16/2023] [Accepted: 05/21/2023] [Indexed: 06/27/2023]
Abstract
OBJECTIVE Characterization of the optic nerve through measurement of optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) using transorbital sonography (TOS) has proven to be a useful tool for the evaluation of intracranial pressure (ICP) and multiple neurological conditions. We describe a deep learning-based system for automatic characterization of the optic nerve from B-mode TOS images by automatic measurement of the OND and ONSD. In addition, we determine how the signal-to-noise ratio in two different areas of the image influences system performance. METHODS A UNet was trained as the segmentation model. The training was performed on a multidevice, multicenter data set of 464 TOS images from 110 subjects. Fivefold cross-validation was performed, and the training process was repeated eight times. The final prediction was made as an ensemble of the predictions of the eight single models. Automatic OND and ONSD measurements were compared with the manual measurements taken by an expert with a graphical user interface that mimics a clinical setting. RESULTS A Dice score of 0.719 ± 0.139 was obtained on the whole data set merging the test folds. Pearson's correlation was 0.69 for both OND and ONSD parameters. The signal-to-noise ratio was found to influence segmentation performance, but no clear correlation with diameter measurement performance was determined. CONCLUSION The developed system has a good correlation with manual measurements, proving that it is feasible to create a model capable of automatically analyzing TOS images from multiple devices. The promising results encourage further definition of a standard protocol for the automatization of the OND and ONSD measurement process using deep learning-based methods. The image data and the manual measurements used in this work will be available at 10.17632/kw8gvp8m8x.1.
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Affiliation(s)
- Francesco Marzola
- Biolab, Department of Electronics and Communications, Politecnico di Torino, Torino, Italy.
| | | | - Andrea Naldi
- Neurology Unit, San Giovanni Bosco Hospital, Turin, Italy
| | - Robert Lemor
- Department of Biomedical Engineering, Saarland University of Applied Sciences, Saarbrücken, Germany
| | | | - Kristen M Meiburger
- Biolab, Department of Electronics and Communications, Politecnico di Torino, Torino, Italy
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Uttanganakam S, Hansda U, Sahoo S, Shaji IM, Guru S, Topno N, Sahoo NK. Sonographic Optic Nerve Sheath Diameter as a Guide for Correction of Hyponatremia in the Emergency Department: A Cross-sectional Study. Indian J Crit Care Med 2023; 27:265-269. [PMID: 37378026 PMCID: PMC10291655 DOI: 10.5005/jp-journals-10071-24438] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/20/2023] [Indexed: 08/30/2024] Open
Abstract
BACKGROUND Monitoring sodium levels during the correction of hyponatremia is essential. There is cell swelling due to the movement of water from extracellular to intracellular by osmotic effect in hyponatremia. The cellular swelling in a closed space causes increased intracranial pressure (ICP). The raised ICP correlates with the optic nerve sheath diameter (ONSD). So, the research question was whether the ONSD can be used as a guide for the correction of hyponatremia. METHODS It was a prospective observational study conducted on patients with serum sodium below 135 mEq/L presented to the emergency department (ED). The ONSD was measured at the time of presentation and discharge of the patient. The receiver operating characteristic curve (ROC) and area under the curve (AUC) were used to test the predictive ability of the ONSD to diagnose hyponatremia. RESULTS A total of 54 subjects were included in the study. The mean sodium level was 109.3 mEq/L at presentation. The mean ONSD on the right side was 6.24 ± 0.71 mm and on the left side was 6.26 ± 0.64 mm at presentation to ED. The mean ONSD on the right side was 5.81 ± 0.58 mm and on the left side was 5.79 ± 0.56 mm at discharge. The ONSD was not able to predict the sodium level measured both by laboratory and POC methods. CONCLUSION The ONSD failed to predict the sodium level in patients with hyponatremia during the correction. The change in ONSD did not correlate with the change in sodium level. HOW TO CITE THIS ARTICLE Uttanganakam S, Hansda U, Sahoo S, Shaji IM, Guru S, Topno N, et al. Sonographic Optic Nerve Sheath Diameter as a Guide for Correction of Hyponatremia in the Emergency Department: A Cross-sectional Study. Indian J Crit Care Med 2023;27(4):265-269.
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Affiliation(s)
- Sanjeed Uttanganakam
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Upendra Hansda
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Sangeeta Sahoo
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Ijas Muhammed Shaji
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Satyabrata Guru
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Nitish Topno
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
| | - Nishit Kumar Sahoo
- Department of Trauma and Emergency, All India Institute of Medical Sciences, Bhubaneswar, Odisha, India
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Lynch DG, Narayan RK, Li C. Multi-Mechanistic Approaches to the Treatment of Traumatic Brain Injury: A Review. J Clin Med 2023; 12:jcm12062179. [PMID: 36983181 PMCID: PMC10052098 DOI: 10.3390/jcm12062179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 03/18/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. Despite extensive research efforts, the majority of trialed monotherapies to date have failed to demonstrate significant benefit. It has been suggested that this is due to the complex pathophysiology of TBI, which may possibly be addressed by a combination of therapeutic interventions. In this article, we have reviewed combinations of different pharmacologic treatments, combinations of non-pharmacologic interventions, and combined pharmacologic and non-pharmacologic interventions for TBI. Both preclinical and clinical studies have been included. While promising results have been found in animal models, clinical trials of combination therapies have not yet shown clear benefit. This may possibly be due to their application without consideration of the evolving pathophysiology of TBI. Improvements of this paradigm may come from novel interventions guided by multimodal neuromonitoring and multimodal imaging techniques, as well as the application of multi-targeted non-pharmacologic and endogenous therapies. There also needs to be a greater representation of female subjects in preclinical and clinical studies.
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Affiliation(s)
- Daniel G. Lynch
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, USA
- Zucker School of Medicine at Hofstra/Northwell Health, Hempstead, NY 11549, USA
| | - Raj K. Narayan
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, USA
- Department of Neurosurgery, St. Francis Hospital, Roslyn, NY 11576, USA
| | - Chunyan Li
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, USA
- Zucker School of Medicine at Hofstra/Northwell Health, Hempstead, NY 11549, USA
- Department of Neurosurgery, Northwell Health, Manhasset, NY 11030, USA
- Correspondence:
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Extracorporeal Circulation and Optic Nerve Ultrasound: A Pilot Study. Medicina (B Aires) 2023; 59:medicina59030445. [PMID: 36984445 PMCID: PMC10058668 DOI: 10.3390/medicina59030445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/09/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
Background and Objectives: Cardiopulmonary bypass (CPB) is an extracorporeal circuit that provides surgical access to an immobile and bloodless area, allowing for technical and procedural advances in cardiothoracic surgery. CBP can alter the integrity of the blood–brain barrier and cause changes in intracranial pressure (ICP) postoperatively. Optical nerve sheath diameter (ONSD) measurement is among the alternative non-invasive methods for ICP monitoring. In this study, we aimed to evaluate the optic nerve sheath diameter measurements under the guidance of ultrasonography for ICP changes during the extracorporeal circulation process. Materials and Methods: The study population included 21 patients over 18 years of age who required extracorporeal circulation. Demographic data of the patients, such as age, gender, comorbidity, American Society of Anesthesiologists (ASA) classification and reason for operation (coronary artery disease or mitral or aortic valve disease) were recorded. The ONSD was measured and evaluated before the extracorporeal circulation (first time) and at the 30th minute (second time), 60th minute (third time) and 90th minute (fourth time) of the extracorporeal circulation. Non-invasive ICP (ICP ONSD) values were calculated based on the ONSD values found. Results: The mean ONSD values measured before the extracorporeal circulation of the patients were found to be 4.13 mm (3.8–4.6) for the right eye and 4.36 mm (4.1–4.7) for the left eye. Calculated nICPONSD values of 11.0 mm Hg (1.0–21.0) for the right eye and 10.89 mm Hg (1.0–21.0) for the left eye were found. It was observed that there was a significant increase in the ONSD and nlCPONSD values recorded during the extracorporeal circulation of all patients compared to the baseline values (p < 0.005). Conclusions: During extracorporeal circulation, ultrasound-guided ONSD measurement is an easy, inexpensive and low-complication method that can be performed at the bedside during the operation to monitor ICP changes.
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Trocha G, Bonilla A, Romero C, Palacios J, Molano-Gonzalez N. Ultrasound measurement of optic nerve sheath diameter in a healthy adult Colombian population. BMC Neurol 2023; 23:16. [PMID: 36639617 PMCID: PMC9837461 DOI: 10.1186/s12883-023-03062-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 10/12/2022] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Measurement of the optic nerve sheath diameter (ONSD) provides a rapid, safe, and easy method for detecting increased intracranial pressure (ICP). However, the normal mean and upper limit values may vary according to sex, age, ethnicity, and ultrasound technique. AIM We aimed to obtain the mean ONSD in a healthy Colombian adult population and to correlate it with demographic and anthropometric measures. METHODS In a prospective study using a 10-13 MHz linear ultrasound probe, eye transverse diameter (ETD) and ONSD in the transverse (ONSD-TP) and sagittal planes (ONSD-SP) were measured in healthy adult volunteers in Bogota, Colombia. RESULTS A total of 100 healthy subjects were included, with a mean age of 26,7 ± 8,3 years and 62 women. The mean ETD, ONSD-TP and ONSD-SP was 23.11 mm (95% confidence interval (CI): 22.90 mm-23.32 mm), 3.96 mm (95% CI: 3.85 mm-4.07 mm) and 4.0 mm (95% CI: 3.90 mm-4.11 mm), respectively. The ONSD in both planes ranged from 2.35 mm to 5.20 mm. There was a significant correlation between ONSD-SP and ONSD-TP (p < 0.0001) but no correlation between the ocular measures and demographic or anthropometric variables (p > 0.05). The intraclass correlation between the eyes was statistically significant. CONCLUSION Our study shows that ultrasound-measured ONSD in healthy adults in Colombia is similar to that found worldwide. An ONSD of 5.5 mm may be considered the upper limit for healthy adults in Colombia. ONSD can be measured in either plane; there is a good correlation between the two eyes; and ONSD is not modified by demographic or anthropometric characteristics.
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Affiliation(s)
- Guillermo Trocha
- grid.488756.0Department of Neurology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Andrés Bonilla
- grid.488756.0Department of Neurology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Camilo Romero
- grid.488756.0Department of Neurology, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Jonathan Palacios
- grid.488756.0Department of Critical Care Medicine, Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia
| | - Nicolas Molano-Gonzalez
- grid.412191.e0000 0001 2205 5940Clinical Research Group, School of Medicine and Health Science, Universidad del Rosario, Bogotá, Colombia
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Snelling PJ, Jones P, Moore M, Gimpel P, Rogers R, Liew K, Ware RS, Keijzers G. Describing the learning curve of novices for the diagnosis of paediatric distal forearm fractures using point-of-care ultrasound. Australas J Ultrasound Med 2022; 25:66-73. [PMID: 35722050 PMCID: PMC9201201 DOI: 10.1002/ajum.12291] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Purpose The learning curve of nurse practitioners (NPs) to accurately diagnose paediatric distal forearm fractures using point-of-care ultrasound (POCUS) was investigated. Methods Each NP's learning curve was calculated as cumulative diagnostic accuracy against a number of scans performed. The curve's plateau represented the attainment of competency. Secondary outcomes were the comparisons before and after this cut-off of diagnostic accuracy, classification of diagnostic errors, pain scores, duration and preference. Results Five NPs performed 201 POCUS studies with diagnostic accuracy plateauing at 90%, providing a 'cut-off' point at scan 15. Accuracy of POCUS scanning before and after the fifteenth scan was 81% (95% CI 70%-89%) and 90% (95% CI 84%-94%), respectively, demonstrating 9% improvement (P = 0.07). There was a 10% reduction in image interpretation errors. After fifteen scans, POCUS became faster (mean difference (MD) 2.6 min [95% CI 2.0-3.3], P < 0.001), less painful (MD 0.61 points FPSR scale [95% CI 0.04-1.18], P = 0.04) and more preferred by NPs (63% vs 77%, P = 0.03). Discussion The learning curve of POCUS-novice NPs independently scanning paediatric distal forearm injuries plateaued with mean diagnostic accuracy of 90% after 15 scans, suggesting competency was attained at this cut-off, supported by higher accuracy, being faster, less painful and more preferred by NPs. Future training packages in forearm POCUS should further address image interpretation and provide ongoing expert feedback. Conclusions The findings from this study suggest that competency in paediatric distal forearm POCUS can be attained by novices after a short training course and approximately 15 scans.
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Affiliation(s)
- Peter J Snelling
- School of Medicine and Dentistry and Menzies Health Institute Queensland Griffith University Southport Queensland Australia.,Emergency Department Gold Coast University Hospital Southport Queensland Australia.,Sonography Innovation and Research (Sonar) Group Southport Queensland Australia.,Child Health Research Centre University of Queensland Southport Queensland Australia.,Emergency Department Queensland Children's Hospital South Brisbane Queensland Australia
| | - Philip Jones
- School of Medicine and Dentistry and Menzies Health Institute Queensland Griffith University Southport Queensland Australia.,Emergency Department Gold Coast University Hospital Southport Queensland Australia.,Emergency and Trauma Centre Royal Brisbane and Women's Hospital Herston Queensland Australia
| | - Mark Moore
- Emergency Department Queensland Children's Hospital South Brisbane Queensland Australia
| | - Peta Gimpel
- Emergency Department Queensland Children's Hospital South Brisbane Queensland Australia
| | - Rosemary Rogers
- Emergency Department Queensland Children's Hospital South Brisbane Queensland Australia
| | - Kong Liew
- Emergency Department Queensland Children's Hospital South Brisbane Queensland Australia
| | - Robert S Ware
- School of Medicine and Dentistry and Menzies Health Institute Queensland Griffith University Southport Queensland Australia
| | - Gerben Keijzers
- School of Medicine and Dentistry and Menzies Health Institute Queensland Griffith University Southport Queensland Australia.,Emergency Department Gold Coast University Hospital Southport Queensland Australia.,Faculty of Health Sciences and Medicine Bond University Gold Coast Queensland Australia
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7
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Korsbæk JJ, Hagen SM, Schytz HW, Vukovic-Cvetkovic V, Wibroe EA, Hamann S, Jensen RH. Transorbital sonography: A non-invasive bedside screening tool for detection of pseudotumor cerebri syndrome. Cephalalgia 2022; 42:1116-1126. [PMID: 35469442 DOI: 10.1177/03331024221094293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Our objective was to assess optic nerve sheath diameter (a marker of elevated intracranial pressure) and optic disc elevation (a marker of papilledema) in pseudotumor cerebri syndrome using transorbital sonography. METHODS The study was a prospective case-control study. We included patients with new-onset pseudotumor cerebri syndrome and matched healthy controls. All had fundoscopy, lumbar puncture with opening pressure and transorbital sonography. Sonography was assessed by a blinded observer. RESULTS We evaluated 45 patients and included 23 cases. We recruited 35 controls. Optic nerve sheath diameter was larger in pseudotumor cerebri syndrome compared to controls (6.3 ± 0.9 mm versus 5.0 ± 0.5 mm, p < 0.001) and so was optic disc elevation (0.9 ± 0.4 mm versus 0.4 ± 0.1 mm, p < 0.001). The optimal cut-off point for optic nerve sheath diameter was 6 mm with a sensitivity of 74% for prediction of pseudotumor cerebri syndrome and 68% for prediction of elevated opening pressure. Specificity was 94%. The optimal cut-off point for optic disc elevation was 0.6 mm. Sensitivity was 100% and specificity 83% for prediction of pseudotumor cerebri syndrome. CONCLUSION Optic disc elevation and optic nerve sheath diameter are increased in new-onset pseudotumor cerebri syndrome. Optic disc elevation achieved high specificity and excellent sensitivity for diagnosis of pseudotumor cerebri syndrome. Transorbital sonography (TOS) is a potential, non-invasive screening tool for pseudotumor cerebri syndrome in headache clinics.
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Affiliation(s)
- Johanne Juhl Korsbæk
- Danish Headache Center, Department of Neurology, Rigshospitalet, University of Copenhagen
| | - Snorre Malm Hagen
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen
| | - Henrik W Schytz
- Danish Headache Center, Department of Neurology, Rigshospitalet, University of Copenhagen
| | | | | | - Steffen Hamann
- Department of Ophthalmology, Rigshospitalet, University of Copenhagen
| | - Rigmor H Jensen
- Danish Headache Center, Department of Neurology, Rigshospitalet, University of Copenhagen
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Dadon Z, Butnaru A, Rosenmann D, Alper‐Suissa L, Glikson M, Alpert EA. Use of artificial intelligence as a didactic tool to improve ejection fraction assessment in the emergency department: A randomized controlled pilot study. AEM EDUCATION AND TRAINING 2022; 6:e10738. [PMID: 35493288 PMCID: PMC9045570 DOI: 10.1002/aet2.10738] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
OBJECTIVES Incorporating artificial intelligence (AI) into echocardiography operated by clinicians working in the emergency department to accurately assess left-ventricular ejection fraction (LVEF) may lead to better diagnostic decisions. This randomized controlled pilot study aimed to evaluate AI use as a didactic tool to improve noncardiologist clinicians' assessment of LVEF from the apical 4-chamber (A4ch) view. METHODS This prospective randomized controlled pilot study tested the feasibility and acceptability of the incorporation of AI as a didactic tool by comparing the ability of 16 clinicians who work in the emergency department to assess LVEF before and after the introduction of an AI-based ultrasound application. Following a brief didactic course, participants were randomly equally divided into an intervention and a control group. In each of the first and second sessions, both groups were shown 10 echocardiography A4ch clips and asked to assess LVEF. Following each clip assessment, only the intervention group was shown the results of the AI-based tool. For the final session, both groups were presented with a new set of 40 clips and asked to evaluate the LVEF. RESULTS In the "normal-abnormal" category evaluation, as related to own baseline accuracy assessment, the intervention group had an improvement in accuracy on 50 consecutive clip assessments compared with a decline in the control group (0.10 vs. -0.12, respectively, p = 0.038). In the "significantly reduced LVEF" category, the intervention group showed significantly less decline in clip assessment as compared to the control group (-0.03 vs. -0.12, respectively, p = 0.050). CONCLUSIONS A study involving AI incorporation as a didactic tool for clinicians working in the emergency department appears feasible and acceptable. The introduction of an AI-based tool to clinicians working in the emergency department improved the assessment accuracy of LVEF as compared to the control group.
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Affiliation(s)
- Ziv Dadon
- Jesselson Integrated Heart CenterShaare Zedek Medical CenterJerusalemIsrael
| | - Adi Butnaru
- Jesselson Integrated Heart CenterShaare Zedek Medical CenterJerusalemIsrael
| | - David Rosenmann
- Jesselson Integrated Heart CenterShaare Zedek Medical CenterJerusalemIsrael
| | - Liat Alper‐Suissa
- Jesselson Integrated Heart CenterShaare Zedek Medical CenterJerusalemIsrael
| | - Michael Glikson
- Jesselson Integrated Heart CenterShaare Zedek Medical CenterThe Faculty of MedicineHebrew University of JerusalemJerusalemIsrael
| | - Evan A. Alpert
- Department of Emergency Medicine, Shaare Zedek Medical CenterThe Faculty of MedicineHebrew University of JerusalemJerusalemIsrael
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Johnson GGRJ, Jelic T, Derksen A, Unger B, Zeiler FA, Ziesmann MT, Gillman LM. Accuracy of Optic Nerve Sheath Diameter Measurements in Pocket-Sized Ultrasound Devices in a Simulation Model. Front Med (Lausanne) 2022; 9:831778. [PMID: 35308521 PMCID: PMC8924410 DOI: 10.3389/fmed.2022.831778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Transorbital sonographic measurement of optic nerve sheath diameter (ONSD) is an emerging non-invasive technique for the identification and monitoring of intracranial hypertension. In recent years, new pocket ultrasound devices have become available, and it is uncertain if they have the resolution to measure such small structures appropriately as compared to their predecessors. In this study, we measure the performance of three ultrasound units on a simulation model to establish their precision and accuracy. Methods ONSD was measured by three expert point-of-care sonographers using ultrasound machines three times on each of seven discrete ONS model sizes ranging from 3.5 to 7.9 mm. Two pocket ultrasounds (IVIZ, Sonosite, and Lumify, Philips) and one standard-sized portable ultrasound (M-Turbo, Sonosite) were used. Measurements were analyzed for mean error and variance and tested for significance using blocked covariance matrix regression analyses. Results The devices differed in their variances (Lumify: 0.19 mm2, M-Turbo: 0.26 mm2, IVIZ: 0.34 mm2) and their mean error (Lumify: -0.05 mm, M-Turbo: 0.10 mm, IVIZ: -0.10 mm). The difference in mean error between users is not significant (p = 0.45), but there is a significant difference in mean error between devices (p = 0.02). Conclusions Accurate ONSD measurement is possible utilizing pocket-sized ultrasound, and in some cases, may be more accurate than larger portable ultrasound units. While the differences in these devices were statistically significant, all three were highly accurate, with one pocket device (Lumify) outperforming the rest. Further study in human subjects should be conducted prior to using pocket ultrasound devices for in vivo diagnosis of intracranial hypertension.
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Affiliation(s)
| | - Tomislav Jelic
- Department of Emergency Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Angela Derksen
- Emergency Department, Seven Oaks General Hospital, Winnipeg, MB, Canada
| | - Bertram Unger
- Department of Internal Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Frederick A Zeiler
- Section of Neurosurgery, Department of Surgery, University of Manitoba, Winnipeg, MB, Canada.,Department of Anatomy and Cell Science, University of Manitoba, Winnipeg, MB, Canada.,Biomedical Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, MB, Canada.,Centre on Aging, University of Manitoba, Winnipeg, MB, Canada.,Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge, United Kingdom
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Optic Nerve Sheath Diameter Ultrasound: A Non-Invasive Approach to Evaluate Increased Intracranial Pressure in Critically Ill Pediatric Patients. Diagnostics (Basel) 2022; 12:diagnostics12030767. [PMID: 35328319 PMCID: PMC8946972 DOI: 10.3390/diagnostics12030767] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/15/2022] [Accepted: 03/15/2022] [Indexed: 01/16/2023] Open
Abstract
Early diagnosis of increased intracranial pressure (ICP) is crucial for prompt diagnosis and treatment of intracranial hypertension in critically ill pediatric patients, preventing secondary brain damage and mortality. Although the placement of an external ventricular drain coupled to an external fluid-filled transducer remains the gold standard for continuous ICP monitoring, other non-invasive approaches are constantly being improved and can provide reliable estimates. The use of point-of-care ultrasound (POCUS) for the assessment of ICP has recently become widespread in pediatric emergency and critical care settings, representing a valuable extension of the physical examination. The aim of this manuscript is to review and discuss the basic principles of ultra-sound measurement of the optic nerve sheath diameter (ONSD) and summarize current evidence on its diagnostic value in pediatric patients with ICP. There is increasing evidence that POCUS measurement of the ONSD correlates with ICP, thus appearing as a useful extension of the physical examination in pediatrics, especially in emergency medicine and critical care settings for the initial non-invasive assessment of patients with suspected raised ICP. Its role could be of value even to assess the response to therapy and in the follow-up of patients with diagnosed intracranial hypertension if invasive ICP monitoring is not available. Further studies on more homogeneous and extensive study populations should be performed to establish ONSD reference ranges in the different pediatric ages and to define cut-off values in predicting elevated ICP compared to invasive ICP measurement.
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Natile M, Simonet O, Vallot F, De Kock M. Ultrasound measurement of the optic nerve sheath diameter in traumatic brain injury: a narrative review. ACTA ANAESTHESIOLOGICA BELGICA 2021. [DOI: 10.56126/72.4.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background : Raised intracranial pressure (ICP) needs to be investigated in various situations, especially in traumatic brain injury (TBI). Ultra-sonographic (US) measurement of the optic nerve sheath diameter (ONSD) is a promising noninvasive tool for assessing elevated ICP.
Objectives : This narrative review aimed to explain the history of and indications forUS measurement of ONSD. We focused on the detection of elevated ICP after TBI and discussed the possible improvements in detection methods.
Conclusions : US measurement of ONSD in TBI cases provides a qualitative but no quantitative assessment of ICP. Current studies usually calculate their own optimum cutoff value for detecting raised ICP based on the balance between sensitivity and specificity of the method when compared with invasive methods. There is no universally accepted threshold. We did not find any paper focusing on the prognosis of patients benefiting from it when compared with usual care. Another limitation is the lack of standardization. US measurement of ONSD cannot be used as the sole technique to detect elevated ICP and monitor its evolution, but it can be a useful tool in a multimodal protocol and it might help to determine the prognosis of patients in various situations.
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12
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Jeng BCP, de Andrade AF, Brasil S, Bor-Seng-Shu E, Belon AR, Robertis M, de-Lima-Oliveira M, Rubiano AM, Godoy DA, Teixeira MJ, Paiva WS. Estimation of intracranial pressure by ultrasound of the optic nerve sheath in an animal model of intracranial hypertension. J Clin Neurosci 2021; 86:174-179. [PMID: 33775322 DOI: 10.1016/j.jocn.2021.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/11/2021] [Accepted: 01/15/2021] [Indexed: 10/22/2022]
Abstract
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.
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Affiliation(s)
| | | | - Sérgio Brasil
- Division of Neurosurgery, University of São Paulo Medical School, São Paulo, Brazil.
| | - Edson Bor-Seng-Shu
- Division of Neurosurgery, University of São Paulo Medical School, São Paulo, Brazil
| | | | - Maira Robertis
- Laboratory of Experimental Surgery, University of São Paulo Medical School, São Paulo, Brazil
| | | | | | - Daniel Agustín Godoy
- Neurointensive Care Unit, Sanatorio Pasteur. Intensive Care Unit, Hospital Carlos G. Malbran, Catamarca, Argentina
| | | | - Wellingson Silva Paiva
- Division of Neurosurgery, University of São Paulo Medical School, São Paulo, Brazil; Hospital Samaritano, Americas Serviços Médicos, São Paulo, Brazil
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13
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Palermo J, Bojanowski M, Langevin S, Denault AY. Point-of-care handheld ophthalmic ultrasound in the diagnosis and evaluation of raised intracranial pressure and Terson syndrome: a description of two cases. Can J Anaesth 2020; 67:353-359. [PMID: 31758491 DOI: 10.1007/s12630-019-01531-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 09/11/2019] [Accepted: 10/02/2019] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Ultrasound (US) examination of the eye can be used to detect and monitor elevated intracranial pressure (ICP) and its consequences. Elevated ICP is transmitted to the contiguous optic nerve and its sheath (dura mater), thus underlying the development of papilledema and a widened sheath diameter. The US measurement of the optic nerve sheath diameter (ONSD) has previously been validated to diagnose and monitor raised ICP. The occurrence of vitreous hemorrhage in association with subarachnoid hemorrhage (SAH)-i.e., Terson syndrome-can also be easily diagnosed using ophthalmic US. Because of its relevance in anesthesia and critical care, we describe how to perform the technique illustrated by two cases. CASE PRESENTATIONS A 72-yr-old man with hydrocephalus secondary to a SAH developed raised ICP following the removal of an external ventricular drainage (EVD) system. Daily ONSD measurements using handheld US allowed us to diagnose and monitor the progression and resolution of the intracranial hypertension following the placement of a second EVD system. We also describe the steps used to obtain ONSD measurements during the ophthalmic US examination of a 53-yr-old woman who presented with a stage IV SAH with concomitant bilateral vitreous hemorrhages or Terson syndrome. CONCLUSION Ophthalmic US using a handheld device to measure and monitor ONSD at the bedside is useful in diagnosing and monitoring the progression of intracranial hypertension following EVD removal in a patient with hydrocephalus secondary to SAH. Ophthalmic US can also be used to identify concomitant vitreous hemorrhage that is associated with a worse prognosis.
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Affiliation(s)
- Jennifer Palermo
- Department of Anesthesiology, Université de Montréal, Montreal, QC, Canada
| | - Michel Bojanowski
- Department of Neurosurgery, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada
| | - Stéphan Langevin
- Department of Anesthesiology and Division of Critical Care, Institut Universitaire de Cardiologie et de Pneumologie, Quebec, QC, Canada
| | - André Y Denault
- Division of Critical Care, Centre Hospitalier de l'Université de Montréal, Montreal, QC, Canada.
- Department of Anesthesiology and Critical Care Division, Montreal Heart Institute, Université de Montréal, 5000 Belanger Street, Montreal, QC, H1T 1C8, Canada.
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14
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A New Inexpensive Simulation Model for Ultrasound Assessment of Optic Nerve Sheath Diameter. Can J Neurol Sci 2020; 47:543-548. [PMID: 32077384 DOI: 10.1017/cjn.2020.37] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Sonographic measurement of optic nerve sheath diameter (ONSD) is becoming increasingly accepted as a diagnostic modality to detect elevations in intracranial pressure. As this technique becomes more widespread, methods to address the inherent operator-dependent nature of this modality will need to be developed. We propose a novel low-cost model to accurately simulate sonographic ONSD measurement for purposes of training and assessment. METHODS We designed models composed of medical tubing of various diameters readily available from typical hospital supplies and suspended them in gelatin. The models were evaluated by ultrasound by three expert point-of-care sonographers using a standard linear array probe and technique proposed in the literature. RESULTS This model generates faithful simulation of the ONS that closely approximates in vivo images and can be used to produce accurate, reproducible measurements. Materials are low cost and easy to acquire and assemble. CONCLUSIONS Our model provides realistic simulated images of the ONS. Through comparison of sonographic measurements to the known tube diameters, this model serves as a promising inexpensive tool to teach the method of ultrasound assessment of ONSD or as a way to determine accuracy of this novel ultrasound technology.
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15
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Aspide R, Bertolini G, Albini Riccioli L, Mazzatenta D, Palandri G, Biasucci DG. A Proposal for a New Protocol for Sonographic Assessment of the Optic Nerve Sheath Diameter: The CLOSED Protocol. Neurocrit Care 2020; 32:327-332. [PMID: 31583527 DOI: 10.1007/s12028-019-00853-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Measuring and monitoring of intracranial pressure is considered standard of care in patients with suspected intracranial hypertension. Sonographic assessment of the optic nerve sheath diameter (ONSD) has been promising and potentially useful for noninvasive intracranial hypertension screening. ONSD measurements are easy to perform, repeatable at bedside, fast, low cost, and radiation-free. However, they are still burdened by inter-rater variability, lack of ultrasound (US) setting standardization (e.g., US frequency, focus depth, etc.), and possible artifacts. To overcome this problem, we propose the CLOSED protocol associated with equipment specifications, as a guide to minimize the occurrence of such artifacts enabling a more reliable and accurate measurement. We suggest that color Doppler could be used as a new standard evaluation for the ONSD.
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Affiliation(s)
- Raffaele Aspide
- Anesthesia and Neurointensive Care Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Via Altura, 3, 40139, Bologna, Italy.
| | - Giacomo Bertolini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Luca Albini Riccioli
- Neuroradiology Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Diego Mazzatenta
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
- Department of Neurosurgery, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Giorgio Palandri
- Department of Neurosurgery, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Daniele Guerino Biasucci
- Neurointensive Care Unit, Department of Emergency, Anesthesiology and Intensive Care Medicine, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
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16
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Ogle KY, Lewiss RE. Optic Nerve Sheath Ultrasonography: Should We Be Using It for Bedside Diagnosis of Increased Intracranial Pressure? Ann Intern Med 2019; 171:935-936. [PMID: 31739343 DOI: 10.7326/m19-2928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Kathleen Y Ogle
- George Washington University Hospital Washington, DC (K.Y.O.)
| | - Resa E Lewiss
- Thomas Jefferson University Hospital Philadelphia, Pennsylvania (R.E.L.)
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17
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Association of optic nerve sheath diameter measurement with hyponatremia in emergency department. Am J Emerg Med 2019; 37:1876-1879. [PMID: 30622006 DOI: 10.1016/j.ajem.2018.12.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/26/2018] [Accepted: 12/27/2018] [Indexed: 11/21/2022] Open
Abstract
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.
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18
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Betcher J, Becker TK, Stoyanoff P, Cranford J, Theyyunni N. Military trainees can accurately measure optic nerve sheath diameter after a brief training session. Mil Med Res 2018; 5:42. [PMID: 30572931 PMCID: PMC6300875 DOI: 10.1186/s40779-018-0189-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 12/05/2018] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Identification of elevated intracranial pressure is important following traumatic brain injury. We assessed the feasibility of educating military trainees on accurately obtaining optic nerve sheath diameter measurements using a brief didactic and hands-on training session. Optic nerve sheath diameter is a noninvasive surrogate marker for elevated intracranial pressure, and may be of value in remote military operations, where rapid triage decisions must be made without access to advanced medical equipment. METHODS Military trainees with minimal ultrasound experience were given a 5-min didactic presentation on optic nerve sheath diameter ultrasound. Trainees practiced optic nerve sheath diameter measurements guided by emergency physician ultrasound experts. Trainees then measured the optic nerve sheath diameter on normal volunteers. Following this, a trained physician measured the optic nerve sheath diameter on the same volunteer as a criterion standard. An average of three measurements was taken. RESULTS Twenty-three military trainees were enrolled. A mixed design ANOVA was used to compare measurements by trainees to those of physicians, with a mean difference of - 0.6 mm (P = 0.76). A Bland-Altman analysis showed that the degree of bias in optic nerve sheath diameter measures provided by trainees was very small: d = - 0.004 for the right eye and d = - 0.007 for the left eye. CONCLUSION This study demonstrates that optic nerve sheath diameter measurement can be accurately performed by novice ultrasonographers after a brief training session. If validated, point-of-care optic nerve sheath diameter measurement could impact the triage of injured patients in remote areas.
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Affiliation(s)
- Joseph Betcher
- Department of Emergency Medicine, Mercy Health Muskegon, 1500 E Sherman Blvd, Muskegon, MI, 49444, USA.
| | - Torben K Becker
- Department of Critical Care Medicine, University of Pittsburgh Medical Center, 200 Lothrop St, Pittsburgh, PA, 15213, USA
| | - Peter Stoyanoff
- Department of Emergency Medicine, Hurley Hospital, 1 Hurley Plaza, Flint, MI, 48503, USA
| | - Jim Cranford
- Department of Psychiatry, University of Michigan, 1500 E Medical Center, Ann Arbor, MI, 48109, USA
| | - Nik Theyyunni
- Department of Emergency Medicine, University of Michigan, 1500 E Medical Center, Ann Arbor, MI, 48109, USA
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Sedille L, Pierre F, Pourrat O, Desseauve D. Keeping eyes on preeclampsia. Pregnancy Hypertens 2018; 13:286-290. [PMID: 30177067 DOI: 10.1016/j.preghy.2018.06.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 06/15/2018] [Accepted: 06/30/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Lucie Sedille
- Department of Obstetrics and Gynecology, University Hospital of Poitiers, CS 90577, 86021 Poitiers Cedex, France; Poitiers University, UFR Medicine and Pharmacy, Poitiers, France.
| | - Fabrice Pierre
- Department of Obstetrics and Gynecology, University Hospital of Poitiers, CS 90577, 86021 Poitiers Cedex, France; Poitiers University, UFR Medicine and Pharmacy, Poitiers, France.
| | - Olivier Pourrat
- Poitiers University, UFR Medicine and Pharmacy, Poitiers, France; ICU and Internal Medicine, University Hospital of Poitiers, CS 90577, 86021 Poitiers Cedex, France.
| | - David Desseauve
- Department of Obstetrics and Gynecology, University Hospital of Poitiers, CS 90577, 86021 Poitiers Cedex, France; Poitiers University, UFR Medicine and Pharmacy, Poitiers, France
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New Optic Nerve Sonography Quality Criteria in the Diagnostic Evaluation of Traumatic Brain Injury. Crit Care Res Pract 2018; 2018:3589762. [PMID: 29854448 PMCID: PMC5952494 DOI: 10.1155/2018/3589762] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 01/23/2018] [Accepted: 03/05/2018] [Indexed: 12/19/2022] Open
Abstract
Background New sonographic quality criteria to optimize optic nerve sheath diameter (ONSD) measurements were suggested. The latter were correlated to elevated intracranial pressure (ICP) in traumatic brain injury (TBI). Aim We investigated whether ONSD measurements were correlated to simultaneous ICP measurements in severe TBI. Methods Forty patients with severe TBI (Marshall Scale ≥II and GCS ≤8) participated in the study. All patients had an intraparenchymal ICP catheter inserted, while ONSD was measured bilaterally, upon admission and over the next 48 hours, based on the new sonographic criteria. A total of 400 ONSD measurements were performed, while mean ONSD values of both eyes were used in the analysis. Results ONSD measurements were strongly correlated to ICP values (r=0.74, p < 0.0001). Receiver operator curve (ROC) analysis revealed that the ONSD cutoff value for predicting elevated ICP was 6.4 mm when using the mean of both eyes (AUC = 0.88, 95% CI = 0.80 to 0.95; sensitivity = 85.3%, specificity = 82.6%). Linear regression analysis nested models revealed that sex (p=0.006) and height (p=0.04) were significant predictors of ONSD values. Conclusion When applying the new sonographic quality criteria, ONSD is strongly correlated to ICP in severe TBI. Whether to use such criteria to monitor ONSD as a proxy for ICP trend in TBI remains to be further explored.
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Ultrasonographic measurement of the optic nerve sheath diameter and its association with eyeball transverse diameter in 585 healthy volunteers. Sci Rep 2017; 7:15906. [PMID: 29162911 PMCID: PMC5698472 DOI: 10.1038/s41598-017-16173-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 11/08/2017] [Indexed: 11/23/2022] Open
Abstract
The optic nerve sheath diameter (ONSD) is considered as an indirect marker for intracranial pressure (ICP). However, the optimal cut-off value for an abnormal ONSD indicating elevated ICP and its associated factors have been unclear. Thus, we investigated normative values for the ONSD using ultrasonography and investigate the potential factors affecting it. We prospectively recruited healthy volunteers between September 2016 and March 2017. A total of 585 individuals were included, in which the mean ONSD was 4.11 mm [95% confidence interval (CI), 4.09–4.14 mm]. Although ONSD was correlated with sex (p = 0.015), height (p = 0.003), and eyeball transverse diameter (ETD) (p < 0.001) in simple linear regression analyses, multiple linear regression analysis revealed that only ETD was independently associated with ONSD (p < 0.001). Accordingly, we further established a normative value for the ONSD/ETD ratio and its associated factors. The mean ONSD/ETD ratio was 0.18 (95% CI, 0.18–0.18), but the ONSD/ETD ratio was not correlated with sex, height, weight, body mass index, and head circumference. Our findings suggest that the ONSD had a strong correlation with ETD, and ONSD/ETD ratio might provide more reliable data than ONSD itself as a marker of ICP.
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