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Comparison of accuracy of optic nerve ultrasound for the detection of intracranial hypertension in the setting of acutely fluctuating vs stable intracranial pressure: post-hoc analysis of data from a prospective, blinded single center study.
Crit Care 2012; 16(3):R79CC

Abstract

INTRODUCTION

Optic nerve sheath diameter (ONSD) measurement with bedside ultrasound has been shown in many studies to accurately detect high intracranial pressure (ICP). The accuracy of point-in-time ONSD measurement in the presence of ongoing fluctuation of ICP between high and normal is not known. Recent laboratory investigation suggests that reversal of optic nerve sheath distension may be impaired following bouts of intracranial hypertension. Our objective was to compare the accuracy of ONSD measurement in the setting of fluctuating versus stable ICP.

METHODS

This was a retrospective analysis of data from prospective study comparing ONSD to invasive ICP. Patients with invasive ICP monitors in the ICU underwent ONSD measurement with simultaneous blinded recording of ICP from the invasive monitor. Three measurements were made in each eye. Significant acute ICP fluctuation (SAIF) was defined in two different ways; as the presence of ICP both above and below 20 mmHg within a cluster of six measurements (Definition 1) and as a magnitude of fluctuation >10 mmHg within the cluster (Definition 2). The accuracy of point-in-time ONSD measurements for the detection of concurrent ICP >20 mmHg within clusters fulfilling a specific definition of SAIF was compared to the accuracy of ONSD measurements within clusters not fulfilling the particular definition by comparison of independent receiver operating characteristic (ROC) curves.

RESULTS

A total of 613 concurrent ONSD-ICP measurements in 109 clusters were made in 73 patients. Twenty-three (21%) clusters fulfilled SAIF Definition 1 and 17 (16%) SAIF Definition 2. For Definition 1, the difference in the area under the curve (AUC) of ROC curves for groups with and without fluctuation was 0.10 (P = 0.0001). There was a fall in the specificity from 98% (95% CI 96 to 99%) to 74% (63 to 83%) and in the positive predictive value from 89% (80 to 95%) to 76% (66 to 84%) with fluctuation. For Definition 2, also, there was a significant difference between the AUC of ROC curves of groups with fluctuation-magnitude >10 mmHg and those with fluctuation-magnitude 5 to 10 mmHg (0.06, P = 0.04) as well as <5 mmHg (0.07, P = 0.01).

CONCLUSIONS

Specificity and PPV of ONSD for ICP >20 mmHg are substantially decreased in patients demonstrating acute fluctuation of ICP between high and normal. This may be because of delayed reversal of nerve sheath distension.

Authors

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Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

22578001

Citation

Rajajee, Venkatakrishna, et al. "Comparison of Accuracy of Optic Nerve Ultrasound for the Detection of Intracranial Hypertension in the Setting of Acutely Fluctuating Vs Stable Intracranial Pressure: Post-hoc Analysis of Data From a Prospective, Blinded Single Center Study." Critical Care (London, England), vol. 16, no. 3, 2012, pp. R79.
Rajajee V, Fletcher JJ, Rochlen LR, et al. Comparison of accuracy of optic nerve ultrasound for the detection of intracranial hypertension in the setting of acutely fluctuating vs stable intracranial pressure: post-hoc analysis of data from a prospective, blinded single center study. Crit Care. 2012;16(3):R79.
Rajajee, V., Fletcher, J. J., Rochlen, L. R., & Jacobs, T. L. (2012). Comparison of accuracy of optic nerve ultrasound for the detection of intracranial hypertension in the setting of acutely fluctuating vs stable intracranial pressure: post-hoc analysis of data from a prospective, blinded single center study. Critical Care (London, England), 16(3), pp. R79. doi:10.1186/cc11336.
Rajajee V, et al. Comparison of Accuracy of Optic Nerve Ultrasound for the Detection of Intracranial Hypertension in the Setting of Acutely Fluctuating Vs Stable Intracranial Pressure: Post-hoc Analysis of Data From a Prospective, Blinded Single Center Study. Crit Care. 2012 May 11;16(3):R79. PubMed PMID: 22578001.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparison of accuracy of optic nerve ultrasound for the detection of intracranial hypertension in the setting of acutely fluctuating vs stable intracranial pressure: post-hoc analysis of data from a prospective, blinded single center study. AU - Rajajee,Venkatakrishna, AU - Fletcher,Jeffrey James, AU - Rochlen,Lauryn Renee, AU - Jacobs,Teresa Lee, Y1 - 2012/05/11/ PY - 2012/02/08/received PY - 2012/05/11/accepted PY - 2012/5/15/entrez PY - 2012/5/15/pubmed PY - 2015/6/24/medline SP - R79 EP - R79 JF - Critical care (London, England) JO - Crit Care VL - 16 IS - 3 N2 - INTRODUCTION: Optic nerve sheath diameter (ONSD) measurement with bedside ultrasound has been shown in many studies to accurately detect high intracranial pressure (ICP). The accuracy of point-in-time ONSD measurement in the presence of ongoing fluctuation of ICP between high and normal is not known. Recent laboratory investigation suggests that reversal of optic nerve sheath distension may be impaired following bouts of intracranial hypertension. Our objective was to compare the accuracy of ONSD measurement in the setting of fluctuating versus stable ICP. METHODS: This was a retrospective analysis of data from prospective study comparing ONSD to invasive ICP. Patients with invasive ICP monitors in the ICU underwent ONSD measurement with simultaneous blinded recording of ICP from the invasive monitor. Three measurements were made in each eye. Significant acute ICP fluctuation (SAIF) was defined in two different ways; as the presence of ICP both above and below 20 mmHg within a cluster of six measurements (Definition 1) and as a magnitude of fluctuation >10 mmHg within the cluster (Definition 2). The accuracy of point-in-time ONSD measurements for the detection of concurrent ICP >20 mmHg within clusters fulfilling a specific definition of SAIF was compared to the accuracy of ONSD measurements within clusters not fulfilling the particular definition by comparison of independent receiver operating characteristic (ROC) curves. RESULTS: A total of 613 concurrent ONSD-ICP measurements in 109 clusters were made in 73 patients. Twenty-three (21%) clusters fulfilled SAIF Definition 1 and 17 (16%) SAIF Definition 2. For Definition 1, the difference in the area under the curve (AUC) of ROC curves for groups with and without fluctuation was 0.10 (P = 0.0001). There was a fall in the specificity from 98% (95% CI 96 to 99%) to 74% (63 to 83%) and in the positive predictive value from 89% (80 to 95%) to 76% (66 to 84%) with fluctuation. For Definition 2, also, there was a significant difference between the AUC of ROC curves of groups with fluctuation-magnitude >10 mmHg and those with fluctuation-magnitude 5 to 10 mmHg (0.06, P = 0.04) as well as <5 mmHg (0.07, P = 0.01). CONCLUSIONS: Specificity and PPV of ONSD for ICP >20 mmHg are substantially decreased in patients demonstrating acute fluctuation of ICP between high and normal. This may be because of delayed reversal of nerve sheath distension. SN - 1466-609X UR - https://www.unboundmedicine.com/medline/citation/22578001/Comparison_of_accuracy_of_optic_nerve_ultrasound_for_the_detection_of_intracranial_hypertension_in_the_setting_of_acutely_fluctuating_vs_stable_intracranial_pressure:_post_hoc_analysis_of_data_from_a_prospective_blinded_single_center_study_ L2 - https://ccforum.biomedcentral.com/articles/10.1186/cc11336 DB - PRIME DP - Unbound Medicine ER -