title: The effect of remifentanil on cerebral blood flow velocity in children anesthetized with propofol.
abstract: BACKGROUND
  Cerebrovascular stability and rapid anesthetic emergence are desirable features of a neuroanesthetic regimen. In this randomized crossover study the effect of a low-dose remifentanil infusion on cerebral blood flow velocity (CBFV) in children anesthetized with propofol was evaluated.
  
  
  METHODS
  Twenty healthy children aged 1-6 years undergoing urological surgery were enrolled. Following face mask induction with sevoflurane, anesthesia was maintained with a standardized propofol infusion. Rocuronium was used to facilitate tracheal intubation and normothermia, and normocapnia were maintained. All children received a caudal epidural block, and a transcranial Doppler probe was placed to measure middle cerebral artery blood flow velocity (Vmca). Each patient received a remifentanil regimen of 0.5 microg x kg(-1) followed by 0.2 microg x kg(-1) x min(-1) in a predetermined order of remifentanil + propofol or propofol alone. Vmca, mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously at equilibrium with and without remifentanil.
  
  
  RESULTS
  The combination of remifentanil and propofol caused an 8.1% decrease in MAP (P = 0.0005) and an 11.8% decrease in HR (P < 0.0001) compared with propofol alone. Vmca was not different between the two groups (P = 0.4041).
  
  
  CONCLUSIONS
  The addition of remifentanil to propofol anesthesia in children causes a reduction in MAP and HR without affecting CBFV. This may imply that cerebral blood pressure autoregulation is preserved in children under propofol and remifentanil anesthesia.
authors.affiliation: Department of Anaesthesia, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Lagace
authors.forename: Cengiz
authors.initials: C
authors.lastname: Karsli
authors.forename: Igor
authors.initials: I
authors.lastname: Luginbuehl
authors.forename: Bruno
authors.initials: B
authors.lastname: Bissonnette
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D001794:Blood Pressure / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007223:Infant; D008297:Male; D020768:Middle Cerebral Artery / Q000187:drug effects / Q000502:physiology; D010880:Piperidines / Q000494:pharmacology*; D015742:Propofol; D000077208:Remifentanil
chemical_list: D000701:Analgesics, Opioid; D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol