title: Anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in isoflurane-anaesthetized sheep.
abstract: OBJECTIVE
  To determine the anaesthetic and cardiorespiratory effects of a constant rate infusion of fentanyl in sheep anaesthetized with isoflurane and undergoing orthopaedic surgery.
  
  
  METHODS
  Prospective, randomised, 'blinded' controlled study.
  
  
  METHODS
  Twenty healthy sheep (weight mean 41.1 ± SD 4.5 kg).
  
  
  METHODS
  Sheep were sedated with intravenous (IV) dexmedetomidine (4 μg kg(-1) ) and morphine (0.2 mg kg(-1) ). Anaesthesia was induced with propofol (1 mg kg(-1)  minute(-1) to effect IV) and maintained with isoflurane in oxygen and a continuous rate infusion (CRI) of fentanyl 10 μg kg(-1)  hour(-1) (group F) or saline (group P) for 100 minutes. The anaesthetic induction dose of propofol, isoflurane expiratory fraction (Fe'iso) required for maintenance and cardiorespiratory measurements were recorded and blood gases analyzed at predetermined intervals. The quality of recovery was assessed. Results were compared between groups using t-tests or Mann-Whitney as relevant.
  
  
  RESULTS
  The propofol induction dose was 4.7 ± 2.4 mg kg(-1) . Fe'iso was significantly lower (by 22.6%) in group F sheep than group P (p = 0). Cardiac index (mean ± SD mL kg(-1)  minute(-1) ) was significantly (p = 0.012) lower in group F (90 ± 15) than group P (102 ± 35). Other measured cardiorespiratory parameters did not differ statistically significantly between groups. Recovery times and recovery quality were statistically similar in both groups.
  
  
  CONCLUSIONS
  Fentanyl reduced isoflurane requirements without clinically affecting the cardiorespiratory stability or post-operative recovery in anaesthetized sheep undergoing orthopaedic surgery.
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.forename: María del Mar
authors.initials: Mdel M
authors.lastname: Granados
authors.forename: Juan
authors.initials: J
authors.lastname: Morgaz
authors.forename: Rocío
authors.initials: R
authors.lastname: Navarrete
authors.forename: Andrés
authors.initials: A
authors.lastname: Fernández-Sarmiento
authors.forename: Rafael
authors.initials: R
authors.lastname: Gómez-Villamandos
authors.forename: Pilar
authors.initials: P
authors.lastname: Muñoz
authors.forename: Setefilla
authors.initials: S
authors.lastname: Quirós
authors.forename: José M
authors.initials: JM
authors.lastname: Carrillo
authors.forename: Ignacio
authors.initials: I
authors.lastname: López-Villalba
authors.forename: Juan M
authors.initials: JM
authors.lastname: Dominguez
mesh_terms: D000769:Anesthesia, Inhalation / Q000662:veterinary; D000771:Anesthesia, Intravenous / Q000662:veterinary; D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000494:pharmacology; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology; D006321:Heart / Q000187:drug effects*; D007530:Isoflurane; D008991:Monitoring, Physiologic / Q000662:veterinary; D009985:Orthopedics / Q000662:veterinary; D012137:Respiratory System / Q000187:drug effects*; D012756:Sheep / Q000601:surgery*
chemical_list: D019162:Anesthetics, Combined; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D007530:Isoflurane; D005283:Fentanyl
keywords: anaesthesia; cardiopulmonary; fentanyl; isoflurane; sheep