title: Individual effect-site concentrations of propofol at return of consciousness are related to the concentrations at loss of consciousness and age in neurosurgical patients.
abstract: OBJECTIVE
  To investigate whether a patient's propofol effect-site concentration at return to consciousness (ROC) was related to the propofol effect-site concentration at loss of consciousness (LOC) and to patients' individual demographic parameters.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Operating room.
  
  
  METHODS
  31 ASA physical status I and II neurosurgical patients with Glasgow Coma Score > 15, and scheduled to receive total intravenous anesthesia with effect-site target controlled infusion (TCI) of propofol and remifentanil.
  
  
  METHODS
  A constant propofol infusion was administered until LOC. At LOC, remifentanil started with a plasma concentration target of 2.5 ng mL(-1).
  
  
  RESULTS
  Propofol concentration at LOC was 4.9 +/- 1 microg mL(-1). At ROC, propofol and remifentanil concentrations were 1.16 +/- 0.3 microg mL(-1) and 3.41 +/- 1.5 ng mL(-1). Significant correlation was observed between propofol concentrations at ROC and LOC, between propofol concentration at ROC and patient age (48.7 +/- 15 yrs), and between propofol concentrations at ROC and LOC, divided by patient's age.
  
  
  CONCLUSIONS
  The correlation between propofol concentrations at ROC and LOC was improved by inclusion of patient age data.
authors.affiliation: Division of Engineering, King's College London, London WC2R 2LS, UK. catarina.nunes@kcl.ac.uk
authors.forename: Catarina S
authors.initials: CS
authors.lastname: Nunes
authors.forename: David A
authors.initials: DA
authors.lastname: Ferreira
authors.forename: Luís
authors.initials: L
authors.lastname: Antunes
authors.forename: Francisco
authors.initials: F
authors.lastname: Lobo
authors.forename: Isabel A
authors.initials: IA
authors.lastname: Santos
authors.forename: Pedro
authors.initials: P
authors.lastname: Amorim
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000762:Anesthesia Recovery Period; D018686:Anesthetics, Intravenous / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003243:Consciousness / Q000187:drug effects; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D010880:Piperidines / Q000493:pharmacokinetics / Q000627:therapeutic use; D015742:Propofol / Q000493:pharmacokinetics* / Q000627:therapeutic use; D011446:Prospective Studies; D000077208:Remifentanil; D055815:Young Adult
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol