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Electroencephalograph variables, drug concentrations and sedation scores in children emerging from propofol infusion

Deirdre M Murray1, Gareth C Thorne, Ann E Rigby-Jones

  • 1Paediatric Intensive Care Unit, Royal Bristol Hospital for Children, Bristol, UK.

Paediatric Anaesthesia
|February 14, 2004
PubMed

Insights

Electroencephalography (EEG) variables, specifically the summed ratio (SR), correlated with propofol levels and arousal in children after cardiac surgery. This may offer a new way to monitor sedative depth, as standard sedation scores were unhelpful.

Area of Science:

  • Anesthesiology
  • Pediatric Critical Care
  • Neurophysiology

Background:

  • Inadequate sedation or oversedation is a significant challenge in pediatric intensive care.
  • Wide variations in drug response and lack of objective tests hinder accurate sedative depth assessment.
  • This pilot study aimed to find objective measures for sedative depth in children.

Purpose of the Study:

  • To identify correlates of propofol concentration and electroencephalographic (EEG) variables with observed behavior.
  • To evaluate the utility of EEG in monitoring sedative depth during propofol infusion reduction.
  • To assess the relationship between EEG, propofol levels, and clinical arousal in pediatric cardiac surgery patients.

Main Methods:

  • Prospective pilot study involving 10 children (5 months to 8 years) post-cardiac surgery.
  • Stepped reduction of propofol infusion rate from 4 mg.kg(-1).h(-1) in 1 mg.kg(-1).h(-1) increments every 30 minutes.
  • Simultaneous recording of EEG variables, propofol blood concentrations, and COMFORT sedation scores.

Main Results:

  • Mean whole blood propofol concentrations at arousal varied significantly [973 ng.ml(-1) (SD 523 ng.ml(-1))].
  • The summed ratio (SR) of high to low frequency EEG bands correlated with propofol infusion rate (R2=0.47) and blood concentration (R2=0.64).
  • SR differed significantly between deeply sedated states and pre-arousal periods (6.84 vs 1.55, P=0.00002), but showed no relation to COMFORT scores.

Conclusions:

  • Standard sedation scores (COMFORT) were unreliable for predicting arousal in this patient group.
  • The summed ratio (SR) demonstrated a strong correlation with propofol blood concentrations and clinical arousal.
  • SR shows potential as an objective tool for predicting arousal and guiding sedation management in pediatric patients.
Abstract

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