title: Evaluation of the isoflurane-sparing effects of fentanyl, lidocaine, ketamine, dexmedetomidine, or the combination lidocaine-ketamine-dexmedetomidine during ovariohysterectomy in dogs.
abstract: OBJECTIVE
  To evaluate the isoflurane-sparing effects of an intravenous (IV) constant rate infusion (CRI) of fentanyl, lidocaine, ketamine, dexmedetomidine, or lidocaine-ketamine-dexmedetomidine (LKD) in dogs undergoing ovariohysterectomy.
  
  
  METHODS
  Randomized, prospective, blinded, clinical study.
  
  
  METHODS
  Fifty four dogs.
  
  
  METHODS
  Anesthesia was induced with propofol and maintained with isoflurane with one of the following IV treatments: butorphanol/saline (butorphanol 0.4 mg kg(-1), saline 0.9% CRI, CONTROL/BUT); fentanyl (5 μg kg(-1), 10 μg kg(-1) hour(-1), FENT); ketamine (1 mg kg(-1), 40 μg kg(-1) minute(-1), KET), lidocaine (2 mg kg(-1), 100 μg kg(-1) minute(-1), LIDO); dexmedetomidine (1 μg kg(-1), 3 μg kg(-1) hour(-1), DEX); or a LKD combination. Positive pressure ventilation maintained eucapnia. An anesthetist unaware of treatment and end-tidal isoflurane concentration (Fe'Iso) adjusted vaporizer settings to maintain surgical anesthetic depth. Cardiopulmonary variables and Fe'Iso concentrations were monitored. Data were analyzed using anova (p < 0.05).
  
  
  RESULTS
  At most time points, heart rate (HR) was lower in FENT than in other groups, except for DEX and LKD. Mean arterial blood pressure (MAP) was lower in FENT and CONTROL/BUT than in DEX. Overall mean ± SD Fe'Iso and % reduced isoflurane requirements were 1.01 ± 0.31/41.6% (range, 0.75 ± 0.31/56.6% to 1.12 ± 0.80/35.3%, FENT), 1.37 ± 0.19/20.8% (1.23 ± 0.14/28.9% to 1.51 ± 0.22/12.7%, KET), 1.34 ± 0.19/22.5% (1.24 ± 0.19/28.3% to 1.44 ± 0.21/16.8%, LIDO), 1.30 ± 0.28/24.8% (1.16 ± 0.18/32.9% to 1.43 ± 0.32/17.3%, DEX), 0.95 ± 0.19/54.9% (0.7 ± 0.16/59.5% to 1.12 ± 0.16/35.3%, LKD) and 1.73 ± 0.18/0.0% (1.64 ± 0.21 to 1.82 ± 0.14, CONTROL/BUT) during surgery. FENT and LKD significantly reduced Fe'Iso.
  
  
  CONCLUSIONS
  At the doses administered, FENT and LKD had greater isoflurane-sparing effect than LIDO, KET or CONTROL/BUT, but not at all times. Low HR during FENT may limit improvement in MAP expected with reduced Fe'Iso.
authors.affiliation: Department of Animal Health and Preventive Medicine, Faculty of Veterinary Medicine, Yucatan Autonomous University, Merida, Mexico; Department of Veterinary Anesthesiology, Faculty of Veterinary Medicine, Mexico State Autonomous University, Toluca, Mexico.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Gutierrez-Blanco
authors.forename: José M
authors.initials: JM
authors.lastname: Victoria-Mora
authors.forename: Jose A
authors.initials: JA
authors.lastname: Ibancovichi-Camarillo
authors.forename: Carlos H
authors.initials: CH
authors.lastname: Sauri-Arceo
authors.forename: Manuel E
authors.initials: ME
authors.lastname: Bolio-González
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Acevedo-Arcique
authors.forename: Gabriela
authors.initials: G
authors.lastname: Marin-Cano
authors.forename: Paulo V M
authors.initials: PV
authors.lastname: Steagall
mesh_terms: D000768:Anesthesia, General / Q000379:methods / Q000662:veterinary*; D019162:Anesthetics, Combined / Q000008:administration & dosage; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000818:Animals; D020927:Dexmedetomidine / Q000008:administration & dosage; D004285:Dogs / Q000601:surgery*; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage; D007044:Hysterectomy / Q000662:veterinary*; D007530:Isoflurane / Q000008:administration & dosage*; D007649:Ketamine / Q000008:administration & dosage; D008012:Lidocaine / Q000008:administration & dosage; D010052:Ovariectomy / Q000662:veterinary*
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D020927:Dexmedetomidine; D007649:Ketamine; D008012:Lidocaine; D007530:Isoflurane; D005283:Fentanyl
keywords: analgesia; anesthesia; balanced anesthesia; dog; isoflurane