Continuous EEG Monitoring

OVERVIEW

  • emerging technique for neurological monitoring
  • not widely used

USES

  • increases sensitivity of detection non-convulsive seizures
  • determine depth of sedation
  • distinguish epileptic from non-epileptic motor activity
  • monitor dynamic changes in brain function e.g. ischemia, vasospasm, rebleeding
  • monitor treatment response (e.g. anti-epileptic drugs)
  • may have a role in prognostication of hypoxic brain injury, intracranial hemorrhage and TBI

INDICATIONS

Consider in patients at high risk of NCSE (~20% risk):

  • patients with seizures
  • patients with coma
  • intracranial haemorrhage
  • SAH
  • encephalitis
  • TBI
  • post cardiac arrest
  • hypoxic ischemic brain injury and metabolic disorders in paediatric patients

METHOD OF USE

Duration of monitoring

  • 24 hours monitoring if not comatose
  • 28-72 hours if comatose
  • If PLED present monitor >24 hours

Reducing interference

  • use of electrical filter
  • may require neuromuscular blockade of movement interference

In some circumstances a modified array or reduced channels may be needed (may reduce sensitivity)

PROS AND CONS

Advantages

  • monitors a dynamic situation
  • provides information at the bedside
  • high sensitivity

Disadvantages

  • labour and resource intensive
  • requires skilled interpretation
  • multiple sources of potential artifact in the ICU setting
    • environmental
      • airflow around bed
      • electrical devices
      • IV drip counters
    • patient factors
      • movements
      • skull defects or hematoma
      • excessive sweating
      • pacemaker interference

OTHER INFORMATION

Non-convulsive seizures

  • without cEEG >50% of non-convulsive status epilepticus (NCSE) is missed in ICUs
  • Non-convulsive seizures (NCS) occur in about 50% of patients with coma or convulsive status epilepticus
  • NCS occur in 8-37% of the general ICU population
  • associated with poorer prognosis and surrogates such as increased neuron-specific enolase and hippocampal atrophy

Sensitivity of cEEG

  • 56% of seizures occur in the first hour of cEEG
  • 88% of seizures occur in the first 24h of cEEG
  • 93% of seizures occur in the first 48h of cEEG

30 minute EEG

  • lacks sensitivity for detecting NCS and NCSE in ICU settings
  • may be used for risk stratification, e.g. if epileptiform discharges then extend monitoring
  • may be performed serially, with increased sensitivity the greater the frequency
  • an option in the absence of cEEG capacity, but still labour and resource intensive

CCC Neurocritical Care Series

Journal articles

  • Caricato A, Melchionda I, Antonelli M. Continuous Electroencephalography Monitoring in Adults in the Intensive Care Unit. Crit Care. 2018;22(1):75. [pubmed]
  • Friedman D, Claassen J, Hirsch LJ. Continuous electroencephalogram monitoring in the intensive care unit. Anesth Analg. 2009 Aug;109(2):506-23.PMID: 19608827.
  • Kennedy JD, Gerard EE. Continuous EEG monitoring in the intensive care unit. Curr Neurol Neurosci Rep. 2012 Aug;12(4):419-28. PMID: 22653639.
  • Sutter R. Are We Prepared to Detect Subtle and Nonconvulsive Status Epilepticus in Critically Ill Patients?. J Clin Neurophysiol. 2016;33(1):25-31. [pubmed]
  • Trinka E, Leitinger M. Which EEG patterns in coma are nonconvulsive status epilepticus?. Epilepsy Behav. 2015;49:203-22. [pubmed]

FOAM and web resources

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the  Clinician Educator Incubator programme, and a CICM First Part Examiner.

He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.

His one great achievement is being the father of three amazing children.

On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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