title: Intravenous 15% isoflurane lipid nanoemulsion for general anesthesia in dogs.
abstract: OBJECTIVE
  To investigate the efficacy of a new intravenous (IV) nanoemulsified isoflurane formulation for maintenance of general anesthesia in dogs.
  
  
  METHODS
  Prospective, crossover, experimental study.
  
  
  METHODS
  Seven healthy, mature, mixed-breed dogs, three male and four female, weighing 11.5 ± 1.5 kg.
  
  
  METHODS
  Anesthesia was induced with propofol for instrumentation. Measurements were obtained before administration of either inhaled isoflurane (Iso-I) or IV 15% isoflurane-loaded lipid nanoemulsion (Iso-nano). The minimum alveolar concentration (MAC) of isoflurane was determined using the 'up-and-down' technique. A tail clamp was applied every 15 minutes for a total time of 90 minutes and isoflurane administration was adjusted according to the response. Data were recorded at 30, 60 and 90 minutes for end-tidal isoflurane concentration (Fe´Iso), end-tidal carbon dioxide partial pressure (Pe'CO2), inspired isoflurane concentration (FIIso), arterial hemoglobin oxygen saturation (SaO2), peripheral hemoglobin oxygen saturation (SpO2), respiratory rate (fR), heart rate (HR), arterial blood pH, PaCO2, PaO2, base excess (BE), bicarbonate (HCO3-), systemic arterial pressure (sAP), and biochemical variables of blood urea nitrogen, alanine aminotransferase, creatine kinase and creatinine.
  
  
  RESULTS
  No significant differences between treatments were detected for HR, fR, SaO2or any biochemical variables (p > 0.05). In the Iso-nano treatment, sAP was significantly decreased throughout the study. Significant decreases in pH, Pe'CO2, BE and HCO3-were measured in the Iso-nano treatment. Isoflurane MAC was significantly lower in the Iso-nano than the Iso-I treatment. The dose of isoflurane (g hour-1) required to maintain general anesthesia did not differ significantly between treatments.
  
  
  CONCLUSIONS
  Administration of 15% isoflurane-loaded lipid nanoemulsion IV was effective in maintaining general anesthesia in dogs but did not reduce the amount of isoflurane necessary to maintain general anesthesia. Significant hypotension and nonrespiratory acidosis occurred with the injectable form.
authors.affiliation: Porto Alegre Clinical Hospital, Animal Medicine Postgraduate Program, Faculty of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. Electronic address: claudio.natalini@ufrgs.br.
authors.forename: Claudio C
authors.initials: CC
authors.lastname: Natalini
authors.affiliation: Porto Alegre Clinical Hospital, Animal Medicine Postgraduate Program, Faculty of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Carolina L
authors.initials: CL
authors.lastname: Krahn
authors.affiliation: Porto Alegre Clinical Hospital, Animal Medicine Postgraduate Program, Faculty of Veterinary Medicine, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Priscila B S
authors.initials: PBS
authors.lastname: Serpa
authors.affiliation: Companion Animal Health Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA, Australia.
authors.forename: Joanna E
authors.initials: JE
authors.lastname: Griffith
authors.affiliation: Faculty of Agronomy and Veterinary Medicine, Central Institute of Sciences, University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Ricardo Miyasaka
authors.initials: RM
authors.lastname: de Almeida
mesh_terms: D000768:Anesthesia, General / Q000379:methods / Q000662:veterinary*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D018592:Cross-Over Studies; D004285:Dogs; D004655:Emulsions; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D007530:Isoflurane / Q000008:administration & dosage*; D008055:Lipids / Q000008:administration & dosage*; D008297:Male; D050997:Nanomedicine; D011446:Prospective Studies
chemical_list: D018686:Anesthetics, Intravenous; D004655:Emulsions; D008055:Lipids; D007530:Isoflurane
keywords: acid-base; halogenated anesthetics; isoflurane; nanoemulsion; nanotechnology