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Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure.
Acad Emerg Med 2008; 15(2):201-4AE

Abstract

BACKGROUND

Measurements of the optic nerve sheath diameter (ONSD) using bedside ultrasound (US) have been shown to correlate with clinical and radiologic signs and symptoms of increased intracranial pressure (ICP).

OBJECTIVES

Previous literature has identified 5 mm as the ONSD measurement above which patients exhibit either clinical or radiologic signs of elevated ICP. The goals of this study were to evaluate the association between ONSD and ICP and to validate the commonly used ONSD threshold of 5 mm using direct measurements of ICP as measured by ventriculostomy.

METHODS

A prospective blinded observational study was performed using a convenience sample of adult patients in both the emergency department (ED) and the neurologic intensive care unit (ICU) who had invasive intracranial monitors placed as part of their clinical care. Ocular USs were performed with a 10(-5) MHz linear probe. Emergency physicians (EPs) with previous ocular US experience performed ONSD measurements while blinded to the contemporaneous ICP reading obtained directly from invasive monitoring. The association between ONSD and ICP was assessed with the Spearman rank correlation coefficient, and a receiver operator characteristic (ROC) curve was created to determine the optimal ONSD cutoff to detect ICP > 20 cm H2O.

RESULTS

Thirty-eight ocular USs were performed on 15 individual patients. Spearman rank correlation coefficient of ONSD and ICP was 0.59 (p < 0.0005) demonstrating a significant positive correlation. An ROC curve was created to assess the ability of ONSD to distinguish an abnormal ICP greater than 20 cm H2O. The area under the ROC curve was 0.93 (95% confidence interval [CI] = 0.84 to 0.99). Based on inspection of the ROC curve, ONSD > 5 mm performed well to detect ICP > 20 cm H(2)O with a sensitivity of 88% (95% CI = 47% to 99%) and specificity of 93% (95% CI = 78% to 99%).

CONCLUSIONS

Using an ROC curve the authors systematically confirmed the commonly used threshold of ONSD > 5 mm to detect ICP > 20 cm H2O. This study directly correlates ventriculostomy measurements of ICP with US ONSD measurements and provides further support for the use of ONSD measurements as a noninvasive test for elevated ICP.

Authors+Show Affiliations

Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA, USA. hkimberly@partners.orgNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Validation Studies

Language

eng

PubMed ID

18275454

Citation

Kimberly, Heidi Harbison, et al. "Correlation of Optic Nerve Sheath Diameter With Direct Measurement of Intracranial Pressure." Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine, vol. 15, no. 2, 2008, pp. 201-4.
Kimberly HH, Shah S, Marill K, et al. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med. 2008;15(2):201-4.
Kimberly, H. H., Shah, S., Marill, K., & Noble, V. (2008). Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Academic Emergency Medicine : Official Journal of the Society for Academic Emergency Medicine, 15(2), pp. 201-4. doi:10.1111/j.1553-2712.2007.00031.x.
Kimberly HH, et al. Correlation of Optic Nerve Sheath Diameter With Direct Measurement of Intracranial Pressure. Acad Emerg Med. 2008;15(2):201-4. PubMed PMID: 18275454.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. AU - Kimberly,Heidi Harbison, AU - Shah,Sachita, AU - Marill,Keith, AU - Noble,Vicki, PY - 2008/2/16/pubmed PY - 2008/2/29/medline PY - 2008/2/16/entrez SP - 201 EP - 4 JF - Academic emergency medicine : official journal of the Society for Academic Emergency Medicine JO - Acad Emerg Med VL - 15 IS - 2 N2 - BACKGROUND: Measurements of the optic nerve sheath diameter (ONSD) using bedside ultrasound (US) have been shown to correlate with clinical and radiologic signs and symptoms of increased intracranial pressure (ICP). OBJECTIVES: Previous literature has identified 5 mm as the ONSD measurement above which patients exhibit either clinical or radiologic signs of elevated ICP. The goals of this study were to evaluate the association between ONSD and ICP and to validate the commonly used ONSD threshold of 5 mm using direct measurements of ICP as measured by ventriculostomy. METHODS: A prospective blinded observational study was performed using a convenience sample of adult patients in both the emergency department (ED) and the neurologic intensive care unit (ICU) who had invasive intracranial monitors placed as part of their clinical care. Ocular USs were performed with a 10(-5) MHz linear probe. Emergency physicians (EPs) with previous ocular US experience performed ONSD measurements while blinded to the contemporaneous ICP reading obtained directly from invasive monitoring. The association between ONSD and ICP was assessed with the Spearman rank correlation coefficient, and a receiver operator characteristic (ROC) curve was created to determine the optimal ONSD cutoff to detect ICP > 20 cm H2O. RESULTS: Thirty-eight ocular USs were performed on 15 individual patients. Spearman rank correlation coefficient of ONSD and ICP was 0.59 (p < 0.0005) demonstrating a significant positive correlation. An ROC curve was created to assess the ability of ONSD to distinguish an abnormal ICP greater than 20 cm H2O. The area under the ROC curve was 0.93 (95% confidence interval [CI] = 0.84 to 0.99). Based on inspection of the ROC curve, ONSD > 5 mm performed well to detect ICP > 20 cm H(2)O with a sensitivity of 88% (95% CI = 47% to 99%) and specificity of 93% (95% CI = 78% to 99%). CONCLUSIONS: Using an ROC curve the authors systematically confirmed the commonly used threshold of ONSD > 5 mm to detect ICP > 20 cm H2O. This study directly correlates ventriculostomy measurements of ICP with US ONSD measurements and provides further support for the use of ONSD measurements as a noninvasive test for elevated ICP. SN - 1553-2712 UR - https://www.unboundmedicine.com/medline/citation/18275454/Correlation_of_optic_nerve_sheath_diameter_with_direct_measurement_of_intracranial_pressure_ L2 - https://doi.org/10.1111/j.1553-2712.2007.00031.x DB - PRIME DP - Unbound Medicine ER -