title: Effect of remifentanil on requirements for propofol administered by use of a target-controlled infusion system for maintaining anesthesia in dogs.
abstract: OBJECTIVE
  To evaluate the effect of remifentanil administered by use of a constant rate infusion on the predicted plasma concentration (Cp(predicted)) of propofol required to prevent awareness in 50% of anesthetized dogs (Cp50(predicted)).
  
  
  METHODS
  6 healthy dogs.
  
  
  METHODS
  Each dog received 2 treatments (1-week interval): induction and maintenance of anesthesia with propofol alone and induction of anesthesia with propofol and maintenance of anesthesia by use of propofol and a constant rate infusion of remifentanil (0.3 microg/kg/min). To induce anesthesia, propofol was administered by use of a target-controlled infusion system to achieve Cp(predicted) of 6.0 microg/mL. Propofol Cp(predicted) was adjusted in 0.5 microg/mL increments or decrements; the motor response to a supramaximal electrical nociceptive stimulus was assessed after each change to determine Cp50(predicted) (mean of the highest Cp(predicted) at which gross purposeful movement was detected in response to stimulation and the lowest Cp(predicted) at which such movement was not detected).
  
  
  RESULTS
  Mean +/- SD duration of anesthesia for dogs receiving propofol (148 +/- 35 minutes) and dogs receiving propofol-remifentanil treatment (141 +/- 28 minutes) did not differ. Overall mean propofol Cp(predicted) for induction of anesthesia was 6.0 +/- 0.5 microg/mL. For maintenance of anesthesia, propofol Cp50(predicted) was significantly reduced following addition of remifentanil to the protocol (2.0 +/- 0.5 microg/mL vs 0.9 +/- 0.4 microg/mL; 55% decrease).
  
  
  CONCLUSIONS
  In nonpremedicated dogs, propofol Cp50(predicted) of 6.0 microg/mL may be recommended for induction of anesthesia. Propofol requirements for maintaining target-controlled infusion system-based anesthesia were reduced via infusion of remifentanil at a rate of 0.3 microg/kg/min.
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, Faculdade de Medicina Veterinária e Zootecnia, Botucatu, São Paulo, 18618-000, Brazil.
authors.forename: Suzane L
authors.initials: SL
authors.lastname: Beier
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: de Araujo Aguiar
authors.forename: Pedro T G
authors.initials: PT
authors.lastname: Vianna
authors.forename: Cláudio R S
authors.initials: CR
authors.lastname: Mattoso
authors.forename: Flavio
authors.initials: F
authors.lastname: Massone
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D008297:Male; D010880:Piperidines / Q000008:administration & dosage* / Q000494:pharmacology*; D015742:Propofol / Q000008:administration & dosage* / Q000494:pharmacology*; D000077208:Remifentanil
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol