title: Isoflurane MAC determination in dogs using three intensities of constant-current electrical stimulation.
abstract: OBJECTIVE
  To compare isoflurane minimum alveolar concentrations (MACs) in dogs determined using three intensities of constant-current electrical stimulation applied at the tail, and thoracic and pelvic limbs, and to compare isoflurane MACs obtained with all combinations of electrical stimulation and anatomic site with those obtained using the tail clamp as the noxious stimulus.
  
  
  METHODS
  Randomized trial.
  
  
  METHODS
  Six mixed-breed, adult female dogs aged 1-2 years and weighing 11.1 ± 4.4 kg.
  
  
  METHODS
  In each dog, MAC was determined by the bracketing method with the tail clamp (MACTAILCLAMP ), and three electrical currents (10 mA, 30 mA, 50 mA) at three anatomic sites (thoracic limb, pelvic limb, tail). Each MAC achieved with electrical stimulation was compared with MACTAILCLAMP using a mixed-model anova and Dunnett's procedure for multiple comparisons. The effects of current intensity and anatomic site on isoflurane MAC were tested using a mixed-model anova followed by Tukey's test for multiple comparisons (p < 0.05).
  
  
  RESULTS
  Mean MACTAILCLAMP was 1.69%. MACs achieved with currents of 30 mA and 50 mA did not differ independently of anatomic site. When currents of 10 mA were applied to the tail and thoracic limb, resulting MACs were lower than those obtained using currents of 30 mA and 50 mA. Currents of 30 mA and 50 mA provided MACs that did not differ from those of MACTAILCLAMP , whereas a current of 10 mA achieved the same result only for the pelvic limb.
  
  
  CONCLUSIONS
  Isoflurane MAC is affected by current intensity and anatomic site. Current intensities of 30 mA and 50 mA provided consistent results when applied to the tail, and thoracic and pelvic limbs that did not differ from those obtained using the tail clamp. Consequently, they can be used in place of the tail clamp in MAC studies in dogs.
authors.affiliation: Veterinary Surgery and Clinics Graduation Program, Veterinary College, Fluminense Federal University, Niterói, Brazil.
authors.forename: Marivaldo R
authors.initials: MR
authors.lastname: Figueiró
authors.affiliation: Veterinary Surgery and Clinics Graduation Program, Veterinary College, Fluminense Federal University, Niterói, Brazil.|Department of Small Animal Clinical Sciences, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
authors.forename: Joao Hn
authors.initials: JH
authors.lastname: Soares
authors.affiliation: Veterinary Surgery and Clinics Graduation Program, Veterinary College, Fluminense Federal University, Niterói, Brazil.
authors.forename: Fabio O
authors.initials: FO
authors.lastname: Ascoli
authors.affiliation: Laboratory for Study Design and Statistical Analysis, Virginia-Maryland Regional College of Veterinary Medicine, Polytechnic Institute and State University, Blacksburg, VA, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Werre
authors.affiliation: Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University Complutense, Madrid, Spain.
authors.forename: Ignacio Á
authors.initials: IÁ
authors.lastname: Gómez de Segura
mesh_terms: D018685:Anesthetics, Inhalation / Q000032:analysis*; D000818:Animals; D004285:Dogs / Q000378:metabolism*; D004558:Electric Stimulation; D005121:Extremities; D005260:Female; D007530:Isoflurane / Q000032:analysis*; D011650:Pulmonary Alveoli / Q000378:metabolism*; D013623:Tail
chemical_list: D018685:Anesthetics, Inhalation; D007530:Isoflurane
keywords: constant-current; dogs; isoflurane; minimum alveolar concentration; noxious stimulation