title: Propofol decreases cerebral blood flow velocity in anesthetized children.
abstract: OBJECTIVE
  Propofol, by virtue of its favourable pharmacokinetic profile, is suitable for maintenance of anesthesia by continuous infusion during neurosurgical procedures in adults. It is gaining popularity for use in pediatric patients. To determine the effects of propofol on cerebral blood flow in children, middle cerebral artery blood flow velocity (Vmca) was measured at different levels of propofol administration by transcranial Doppler (TCD) sonography.
  
  
  METHODS
  Twelve ASA I or II children, aged one to six years undergoing elective urological surgery were randomized to receive one of two propofol dosing regimens. Half of the patients received propofol in an escalating fashion, initially targeting an estimated steady-state serum concentration of 3 microg x mL-1, which was then doubled. The other half received propofol designed initially to target the high concentration followed by the lower one. In each child anesthesia was induced and maintained with propofol according to the protocol, rocuronium was given to facilitate tracheal intubation, and a caudal epidural block was performed. A TCD probe was placed appropriately to measure Vmca. Cerebral blood flow velocity (CBFV), mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at both levels of propofol administration.
  
  
  RESULTS
  Twelve patients were studied. At the higher estimated target serum propofol concentration there were significant decreases in Vmca (17%, P < 0.001), MAP (6%, P < 0.002) and HR (8%, P < 0.05) when compared to the lower targeted concentration.
  
  
  CONCLUSIONS
  This study shows that a higher rate of propofol infusion is associated with lower CBFV and MAP values in children. Propofol's cerebral vasoconstrictive properties may be responsible for this finding.
authors.affiliation: Department of Anesthesia, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Cengiz
authors.initials: C
authors.lastname: Karsli
authors.forename: Igor
authors.initials: I
authors.lastname: Luginbuehl
authors.forename: Mark
authors.initials: M
authors.lastname: Farrar
authors.forename: Bruno
authors.initials: B
authors.lastname: Bissonnette
mesh_terms: D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D001783:Blood Flow Velocity / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D002648:Child; D002675:Child, Preschool; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D015742:Propofol / Q000494:pharmacology*
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol