Median nerve somatosensory evoked potential monitoring during carotid endarterectomy: Does reference choice matter?

Stephen J. Fried, Diane M. Smith, Alan D. Legatt

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Median nerve somatosensory evoked potential monitoring is commonly used during carotid endarterectomy to permit selective shunting in only those patients who are determined to have inadequate collateral flow after carotid cross-clamping. The N20 component is recorded from the CPc (contralateral centroparietal) electrode; either CPi (ipsilateral centroparietal) or Fpz (forehead) can be used as the reference. Because of the distribution of the subcortically generated N18 component, the CPc-Fpz derivation might record both the N20 and the N18 components and might therefore inadequately detect hemispheric ischemia after carotid cross-clamping. Somatosensory evoked potentials recorded were compared using these 2 derivations during 38 carotid endarterectomies to assess their ability to detect neurophysiologic changes after carotid cross-clamping. Although, as expected, the baseline N20 component was significantly larger when recorded with the CPc-Fpz derivation than with the CPc-CPi derivation (3.1 vs. 2.4 μV in the hemisphere ipsilateral to the clamped carotid, P < 0.001), there was no significant difference in the postclamp amplitude decline between the 2 derivations (8.7% vs. 8.6%, P = 0.82). It is concluded that CPc-Fpz is an acceptable derivation for recording postclamp hemispheric somatosensory evoked potential changes during carotid endarterectomy and may be advantageous because it provides a larger amplitude somatosensory evoked potential than the CPc-CPi derivation.

Original languageEnglish (US)
Pages (from-to)55-57
Number of pages3
JournalJournal of Clinical Neurophysiology
Volume31
Issue number1
DOIs
StatePublished - Feb 2014

Fingerprint

Somatosensory Evoked Potentials
Carotid Endarterectomy
Median Nerve
Constriction
Forehead
Electrodes
Ischemia

Keywords

  • Carotid endarterectomy
  • Intraoperative monitoring
  • Median nerve SEP
  • N20
  • Reference electrode
  • Somatosensory evoked potentials

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology
  • Physiology
  • Physiology (medical)

Cite this

Median nerve somatosensory evoked potential monitoring during carotid endarterectomy : Does reference choice matter? / Fried, Stephen J.; Smith, Diane M.; Legatt, Alan D.

In: Journal of Clinical Neurophysiology, Vol. 31, No. 1, 02.2014, p. 55-57.

Research output: Contribution to journalArticle

@article{8cce5d9731a64c95b69ccc475f553021,
title = "Median nerve somatosensory evoked potential monitoring during carotid endarterectomy: Does reference choice matter?",
abstract = "Median nerve somatosensory evoked potential monitoring is commonly used during carotid endarterectomy to permit selective shunting in only those patients who are determined to have inadequate collateral flow after carotid cross-clamping. The N20 component is recorded from the CPc (contralateral centroparietal) electrode; either CPi (ipsilateral centroparietal) or Fpz (forehead) can be used as the reference. Because of the distribution of the subcortically generated N18 component, the CPc-Fpz derivation might record both the N20 and the N18 components and might therefore inadequately detect hemispheric ischemia after carotid cross-clamping. Somatosensory evoked potentials recorded were compared using these 2 derivations during 38 carotid endarterectomies to assess their ability to detect neurophysiologic changes after carotid cross-clamping. Although, as expected, the baseline N20 component was significantly larger when recorded with the CPc-Fpz derivation than with the CPc-CPi derivation (3.1 vs. 2.4 μV in the hemisphere ipsilateral to the clamped carotid, P < 0.001), there was no significant difference in the postclamp amplitude decline between the 2 derivations (8.7{\%} vs. 8.6{\%}, P = 0.82). It is concluded that CPc-Fpz is an acceptable derivation for recording postclamp hemispheric somatosensory evoked potential changes during carotid endarterectomy and may be advantageous because it provides a larger amplitude somatosensory evoked potential than the CPc-CPi derivation.",
keywords = "Carotid endarterectomy, Intraoperative monitoring, Median nerve SEP, N20, Reference electrode, Somatosensory evoked potentials",
author = "Fried, {Stephen J.} and Smith, {Diane M.} and Legatt, {Alan D.}",
year = "2014",
month = "2",
doi = "10.1097/WNP.0000000000000024",
language = "English (US)",
volume = "31",
pages = "55--57",
journal = "Journal of Clinical Neurophysiology",
issn = "0736-0258",
publisher = "Lippincott Williams and Wilkins",
number = "1",

}

TY - JOUR

T1 - Median nerve somatosensory evoked potential monitoring during carotid endarterectomy

T2 - Does reference choice matter?

AU - Fried, Stephen J.

AU - Smith, Diane M.

AU - Legatt, Alan D.

PY - 2014/2

Y1 - 2014/2

N2 - Median nerve somatosensory evoked potential monitoring is commonly used during carotid endarterectomy to permit selective shunting in only those patients who are determined to have inadequate collateral flow after carotid cross-clamping. The N20 component is recorded from the CPc (contralateral centroparietal) electrode; either CPi (ipsilateral centroparietal) or Fpz (forehead) can be used as the reference. Because of the distribution of the subcortically generated N18 component, the CPc-Fpz derivation might record both the N20 and the N18 components and might therefore inadequately detect hemispheric ischemia after carotid cross-clamping. Somatosensory evoked potentials recorded were compared using these 2 derivations during 38 carotid endarterectomies to assess their ability to detect neurophysiologic changes after carotid cross-clamping. Although, as expected, the baseline N20 component was significantly larger when recorded with the CPc-Fpz derivation than with the CPc-CPi derivation (3.1 vs. 2.4 μV in the hemisphere ipsilateral to the clamped carotid, P < 0.001), there was no significant difference in the postclamp amplitude decline between the 2 derivations (8.7% vs. 8.6%, P = 0.82). It is concluded that CPc-Fpz is an acceptable derivation for recording postclamp hemispheric somatosensory evoked potential changes during carotid endarterectomy and may be advantageous because it provides a larger amplitude somatosensory evoked potential than the CPc-CPi derivation.

AB - Median nerve somatosensory evoked potential monitoring is commonly used during carotid endarterectomy to permit selective shunting in only those patients who are determined to have inadequate collateral flow after carotid cross-clamping. The N20 component is recorded from the CPc (contralateral centroparietal) electrode; either CPi (ipsilateral centroparietal) or Fpz (forehead) can be used as the reference. Because of the distribution of the subcortically generated N18 component, the CPc-Fpz derivation might record both the N20 and the N18 components and might therefore inadequately detect hemispheric ischemia after carotid cross-clamping. Somatosensory evoked potentials recorded were compared using these 2 derivations during 38 carotid endarterectomies to assess their ability to detect neurophysiologic changes after carotid cross-clamping. Although, as expected, the baseline N20 component was significantly larger when recorded with the CPc-Fpz derivation than with the CPc-CPi derivation (3.1 vs. 2.4 μV in the hemisphere ipsilateral to the clamped carotid, P < 0.001), there was no significant difference in the postclamp amplitude decline between the 2 derivations (8.7% vs. 8.6%, P = 0.82). It is concluded that CPc-Fpz is an acceptable derivation for recording postclamp hemispheric somatosensory evoked potential changes during carotid endarterectomy and may be advantageous because it provides a larger amplitude somatosensory evoked potential than the CPc-CPi derivation.

KW - Carotid endarterectomy

KW - Intraoperative monitoring

KW - Median nerve SEP

KW - N20

KW - Reference electrode

KW - Somatosensory evoked potentials

UR - http://www.scopus.com/inward/record.url?scp=84894141706&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84894141706&partnerID=8YFLogxK

U2 - 10.1097/WNP.0000000000000024

DO - 10.1097/WNP.0000000000000024

M3 - Article

C2 - 24492447

AN - SCOPUS:84894141706

VL - 31

SP - 55

EP - 57

JO - Journal of Clinical Neurophysiology

JF - Journal of Clinical Neurophysiology

SN - 0736-0258

IS - 1

ER -