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

References and Links

LITFL

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


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

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

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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