title: A comparison of cardiopulmonary effects and anaesthetic requirements of two dexmedetomidine continuous rate infusions in alfaxalone-anaesthetized Greyhounds.
abstract: OBJECTIVE
  To determine the effects of two dexmedetomidine continuous rate infusions on the minimum infusion rate of alfaxalone for total intravenous anaesthesia (TIVA), and subsequent haemodynamic and recovery effects in Greyhounds undergoing laparoscopic ovariohysterectomy.
  
  
  METHODS
  Prospective, randomized and blinded clinical study.
  
  
  METHODS
  Twenty-four female Greyhounds.
  
  
  METHODS
  Dogs were premedicated with dexmedetomidine 3 μg kg-1and methadone 0.3 mg kg-1intramuscularly. Anaesthesia was induced with IV alfaxalone to effect and maintained with a TIVA mixture of alfaxalone in combination with two different doses of dexmedetomidine (0.5 μg kg-1hour-1or 1 μg kg-1hour-1; groups DEX0.5 and DEX1, respectively). The alfaxalone starting dose rate was 0.07 mg kg-1minute-1and was adjusted (± 0.02 mg kg-1minute-1) every 5 minutes to maintain a suitable depth of anaesthesia. A rescue alfaxalone bolus (0.5 mg kg-1IV) was administered if dogs moved or swallowed. The number of rescue boluses was recorded. Heart rate, arterial blood pressure and arterial blood gas were monitored. Qualities of sedation, induction and recovery were scored. Differences between groups were tested for statistical significance using a Student's t test or Mann-Whitney U test as appropriate.
  
  
  RESULTS
  There were no differences between groups in sedation, induction and recovery quality, the median (range) induction dose of alfaxalone [DEX0.5: 2.2 (1.9-2.5) mg kg-1; DEX1: 1.8 (1.2-2.9) mg kg-1], total dose of alfaxalone rescue boluses [DEX0.5: 21.0 (12.5-38.8) mg; DEX1: 22.5 (15.5-30.6) mg] or rate of alfaxalone (DEX0.5: 0.12±0.04 mg kg-1minute-1; DEX1: 0.12±0.03 mg kg-1minute-1).
  
  
  CONCLUSIONS
  Co-administration of dexmedetomidine 1 μg kg-1hour-1failed to reduce the dose rate of alfaxalone compared with dexmedetomidine 0.5 μg kg-1hour-1in Greyhounds undergoing laparoscopic ovariohysterectomy. The authors recommend an alfaxalone starting dose rate of 0.1 mg kg-1minute-1. Recovery quality was good in the majority of dogs.
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain. Electronic address: setequica@hotmail.com.
authors.forename: Setefilla
authors.initials: S
authors.lastname: Quirós-Carmona
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Navarrete
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Domínguez
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: María Del Mar
authors.initials: MDM
authors.lastname: Granados
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Gómez-Villamandos
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Muñoz-Rascón
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Aguilar
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Funes
authors.affiliation: Anaesthesia Unit, Department of Animal Medicine and Surgery, Veterinary Faculty, University of Córdoba, Córdoba, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Morgaz
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007044:Hysterectomy / Q000662:veterinary; D008691:Methadone / Q000008:administration & dosage; D010052:Ovariectomy / Q000662:veterinary; D011229:Preanesthetic Medication / Q000379:methods / Q000662:veterinary*; D011277:Pregnanediones / Q000008:administration & dosage / Q000494:pharmacology*; D011446:Prospective Studies
chemical_list: D000777:Anesthetics; D011277:Pregnanediones; D020927:Dexmedetomidine; C006477:alphaxalone; D008691:Methadone
keywords: alfaxalone; anaesthesia; dexmedetomidine; laparoscopic ovariohysterectomy