title: Minimum infusion rate and hemodynamic effects of propofol, propofol-lidocaine and propofol-lidocaine-ketamine in dogs.
abstract: OBJECTIVE
  To evaluate the effects of a constant rate infusion (CRI) of lidocaine alone or in combination with ketamine on the minimum infusion rate (MIR) of propofol in dogs and to compare the hemodynamic effects produced by propofol, propofol-lidocaine or propofol-lidocaine-ketamine anesthesia.
  
  
  METHODS
  Prospective, randomized cross-over experimental design.
  
  
  METHODS
  Fourteen adult mixed-breed dogs weighing 15.8 ± 3.5 kg.
  
  
  METHODS
  Eight dogs were anesthetized on different occasions to determine the MIR of propofol alone and propofol in combination with lidocaine (loading dose [LD] 1.5 mg kg(-1), CRI 0.25 mg kg(-1) minute(-1)) or lidocaine (LD 1.5 mg kg(-1), CRI 0.25 mg kg(-1) minute(-1)) and ketamine (LD 1 mg kg(-1), CRI 0.1 mg kg(-1) minute(-1)). In six other dogs, the hemodynamic effects and bispectral index (BIS) were investigated. Each animal received each treatment (propofol, propofol-lidocaine or propofol-lidocaine-ketamine) on the basis of the MIR of propofol determined in the first set of experiments.
  
  
  RESULTS
  Mean ± SD MIR of propofol was 0.51 ± 0.08 mg kg(-1) minute(-1). Lidocaine-ketamine significantly decreased the MIR of propofol to 0.31 ± 0.07 mg kg(-1) minute(-1) (37 ± 18% reduction), although lidocaine alone did not (0.42 ± 0.08 mg kg(-1) minute(-1), 18 ± 7% reduction). Hemodynamic effects were similar in all treatments. Compared with the conscious state, in all treatments, heart rate, cardiac index, mean arterial blood pressure, stroke index and oxygen delivery index decreased significantly, whereas systemic vascular resistance index increased. Stroke index was lower in dogs treated with propofol-lidocaine-ketamine at 30 minutes compared with propofol alone. The BIS was lower during anesthesia with propofol-lidocaine-ketamine compared to propofol alone.
  
  
  CONCLUSIONS
  Lidocaine-ketamine, but not lidocaine alone, reduced the MIR of propofol in dogs. Neither lidocaine nor lidocaine in combination with ketamine attenuated cardiovascular depression produced by a continuous rate infusion of propofol.
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, University of São Paulo State, São Paulo, Brazil.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Mannarino
authors.forename: Stelio P L
authors.initials: SP
authors.lastname: Luna
authors.forename: Eduardo R
authors.initials: ER
authors.lastname: Monteiro
authors.forename: Suzane L
authors.initials: SL
authors.lastname: Beier
authors.forename: Vanessa B
authors.initials: VB
authors.lastname: Castro
mesh_terms: D000771:Anesthesia, Intravenous / Q000379:methods / Q000662:veterinary*; D019162:Anesthetics, Combined / Q000008:administration & dosage*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007649:Ketamine / Q000008:administration & dosage*; D008012:Lidocaine / Q000008:administration & dosage*; D015742:Propofol / Q000008:administration & dosage*; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D007649:Ketamine; D008012:Lidocaine; D015742:Propofol