Dynamic optic nerve sheath diameter responses to short-term hyperventilation measured with sonography in patients under general anesthesia

Kim, Jiyeon; Min, Hong-Gi; Ha, Seungil; Jeong, Hye-Won; Seo, Hyungseok; Kim, Joung-Uk

doi:10.4097/kjae.2014.67.4.240

Cited by 21 publications

(15 citation statements)

References 32 publications

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“…These changes in ONSD are direct representation of changes in ICP brought about by changes in CBF due to PaCO 2 changes. Our results correlate well with the study by Kim et al 15 They studied ONSD responsiveness at two levels of EtCO 2 , 40 and 50 mm Hg, each measured at 1 and 5 minutes, and observed significant changes in the diameter of ONSD. According to the available literature, the upper limit of ONSD used to define ICP greater than 20 mm Hg (raised ICP) ranges from 0.48 to 0.57 cm.…”

Section: Discussionsupporting

confidence: 92%

Changes in Optic Nerve Sheath Diameter in Response to Various Levels of End-Tidal Carbon Dioxide in Healthy Patients under General Anesthesia

Kapoor

Khandelwal

Mahajan

et al. 2018

Journal of Neuroanaesthesiology and Critical Care

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Background Intracranial pressure (ICP) monitoring is an essential component in management of traumatic brain-injured (TBI) patients. While invasive techniques are associated with many complications, noninvasive nature of ultrasonographic measurement of optic nerve sheath diameter (ONSD) is now becoming popular. Carbon dioxide (CO 2 ) alters the ICP by changing the size of cerebral vasculature. We aimed to assess the effect of (hypercarbia and hypocarbia) different levels of end-tidal carbon dioxide (EtCO 2 ) on ONSD. Methods Thirty adult patients aged between 18 and 65 years, undergoing brachial plexus injury surgery under general anesthesia, were enrolled. Following standard anesthetic protocol, ONSD was measured at different time points of EtCO 2 . ONSD was measured at EtCO 2 of 40 and then 30 mm Hg to assess change in ONSD due to hypocarbia (T hypocarbia ). Similarly, ONSD was measured at EtCO 2 of 50 mm Hg to assess change in ONSD due to hypercarbia (T hypercarbia ). The mean of three ONSD values at each time point was taken as the final value. The generalized estimating equation (GEE) was used to analyze correlation between different levels of EtCO 2 and ONSD. Results The calculated 95% confidence interval (CI) for the difference of two measures (T hypocarbia, EtCO 2 40 and 30 mm Hg) on ONSD was −0.056 to −0.036, and the calculated CI for the difference of other two measures (T hypercarbia, EtCO 2 40 and 50 mm Hg) on ONSD was 0.044 to 0.077, and thus were observed to be significant. Conclusions ONSD changes significantly in response to different EtCO 2 levels in healthy non-neurosurgical patients under general anesthesia. AbstractKeywords ► optic nerve sheath diameter ► end-tidal carbon dioxide ► intracranial pressure ► hypocapnia ► hypercapnia J Neuroanaesthesiol Crit Care 2018;5:94-97.

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Section: Discussionsupporting

confidence: 92%

Changes in Optic Nerve Sheath Diameter in Response to Various Levels of End-Tidal Carbon Dioxide in Healthy Patients under General Anesthesia

Kapoor

Khandelwal

Mahajan

et al. 2018

Journal of Neuroanaesthesiology and Critical Care

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“…Although the association between arterial CO 2 and ICP is well established, few studies have looked at the dynamic responsiveness of ONSD to acute changes in arterial CO 2 . Moreover, these studies were undertaken in patients whose lungs were mechanically ventilated, and who either had intracranial pathology or were anaesthetised .…”

Section: Discussionmentioning

confidence: 99%

Effects of acute controlled changes in end‐tidal carbon dioxide on the diameter of the optic nerve sheath: a transorbital ultrasonographic study in healthy volunteers

et al. 2017

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Transorbital ultrasonographic measurement of the diameter of the optic nerve sheath is a non-invasive, bed-side examination for detecting raised intracranial pressure. However, the ability of the optic nerve sheath diameter to predict acute changes in intracranial pressures remains unknown. The aim of this study was to examine the dynamic changes of the optic nerve sheath diameter in response to mild fluctuations in cerebral blood volume induced by changes in end-tidal carbon dioxide. We studied 11 healthy volunteers. End-tidal carbon dioxide was controlled by a model-based prospective end-tidal targeting system (RespirAct™). The volunteers' end-tidal carbon dioxide was targeted and maintained for 10 min each at normocapnia (baseline); hypercapnia (6.5 kPa); normocapnia (baseline 1); hypocapnia (3.9 kPa) and on return to normocapnia (baseline 2). A single investigator repeatedly measured the optic nerve sheath diameter for 10 min at each level of carbon dioxide. With hypercapnia, there was a significant increase in optic nerve sheath diameter, with a mean (SD) increase from baseline 4.2 (0.7) mm to 4.8 (0.8) mm; p < 0.001. On return to normocapnia, the optic nerve sheath diameter rapidly reverted back to baseline values. This study confirms dynamic changes in the optic nerve sheath diameter with corresponding changes in carbon dioxide, and their reversibly with normocapnia.

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“…The sheath enveloping the optic nerve is in continuity with the dura mater and the CSF‐containing subarachnoid space of the brain and, because the ONS is distensible, CSF pressure variations influence the volume of ONSD particularly in the anterior, retro‐bulbar compartment, about 3 mm behind the globe . There is a linear relationship between peri‐optic CSF pressure and ICP , and ONSD increases almost directly with ICP , as during osmotic therapy or following CO 2 variations .…”

Section: Optic Nerve Sheath Diameter (Onsd)mentioning

confidence: 99%

Non-invasive assessment of intracranial pressure

et al. 2015

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Monitoring of intracranial pressure (ICP) is invaluable in the management of neurosurgical and neurological critically ill patients. Invasive measurement of ventricular or parenchymal pressure is considered the gold standard for accurate measurement of ICP but is not always possible due to certain risks. Therefore, the availability of accurate methods to non-invasively estimate ICP has the potential to improve the management of these vulnerable patients. This review provides a comparative description of different methods for non-invasive ICP measurement. Current methods are based on changes associated with increased ICP, both morphological (assessed with magnetic resonance, computed tomography, ultrasound, and fundoscopy) and physiological (assessed with transcranial and ophthalmic Doppler, tympanometry, near-infrared spectroscopy, electroencephalography, visual-evoked potentials, and otoacoustic emissions assessment). At present, none of the non-invasive techniques alone seem suitable as a substitute for invasive monitoring. However, following the present analysis and considerations upon each technique, we propose a possible flowchart based on the combination of non-invasive techniques including those characterizing morphologic changes (e.g., repetitive US measurements of ONSD) and those characterizing physiological changes (e.g., continuous TCD). Such an integrated approach, which still needs to be validated in clinical practice, could aid in deciding whether to place an invasive monitor, or how to titrate therapy when invasive ICP measurement is contraindicated or unavailable.

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Dynamic optic nerve sheath diameter responses to short-term hyperventilation measured with sonography in patients under general anesthesia

Cited by 21 publications

References 32 publications

Changes in Optic Nerve Sheath Diameter in Response to Various Levels of End-Tidal Carbon Dioxide in Healthy Patients under General Anesthesia

Changes in Optic Nerve Sheath Diameter in Response to Various Levels of End-Tidal Carbon Dioxide in Healthy Patients under General Anesthesia

Effects of acute controlled changes in end‐tidal carbon dioxide on the diameter of the optic nerve sheath: a transorbital ultrasonographic study in healthy volunteers

Non-invasive assessment of intracranial pressure

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