title: Thoracic epidural analgesia via the lumbosacral approach using multiport catheters with a low concentration of bupivacaine and morphine in sheep.
abstract: OBJECTIVE
  To determine the analgesic and systemic effects of thoracic epidural administration of bupivacaine (BP) and morphine (MP) in conscious sheep.
  
  
  METHODS
  Randomized, crossover, experimental study.
  
  
  METHODS
  Six healthy castrated sheep weighing between 40 and 50 kg.
  
  
  METHODS
  Each sheep received, via the lumbosacral approach, BP (0.5 mg kg(-1)), MP (0.1 mg kg(-1)), and BP plus MP (BPMP; 0.25 mg kg(-1) + 0.05 mg kg(-1)) in a randomized order. Heart rate, blood pressure, respiratory rate, blood gas analysis, skin temperature, rectal temperature, analgesia, sedation, and motor blockade were determined before treatment and at predetermined intervals until analgesia had disappeared.
  
  
  RESULTS
  The main areas of complete analgesia for the BP and BPMP treatments were the thorax and forelimb bilaterally. The median duration of analgesia was shorter with MP treatment (45 minutes; score 2) than with BP treatment (70 minutes) and BPMP treatment (140 minutes; p < 0.05). The BP and BPMP treatments caused motor block, and MP and BPMP treatments showed mild sedation. Significant decreases in systolic and diastolic arterial blood pressures were observed only with the BP treatment (p < 0.05). Epidural MP combined with the BP local anesthetic depressed ventilation but within acceptable limits in these clinically healthy sheep.
  
  
  CONCLUSIONS
  Thoracic epidural administration of BPMP to sheep resulted in longer duration of analgesia of the thorax and forelimbs bilaterally in conscious sheep than the administration of MP or BP alone. The incidence of complications was low, but side-effects such as depressed ventilation and muscle paralysis occurred and require appropriate management.
  
  
  CONCLUSIONS
  This technique should be considered as another method for the relief of postoperative pain after thoracic surgery in sheep.
authors.affiliation: Department of Veterinary Medicine, Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Campo Grande, Brazil. rafael.rossi@ufms.br
authors.forename: Rafael
authors.initials: R
authors.lastname: DeRossi
authors.forename: Ronaldo
authors.initials: R
authors.lastname: Pagliosa
authors.forename: Tiago C
authors.initials: TC
authors.lastname: Módolo
authors.forename: Felipe B
authors.initials: FB
authors.lastname: Maciel
authors.forename: Gustavo G
authors.initials: GG
authors.lastname: Macedo
mesh_terms: D015360:Analgesia, Epidural / Q000662:veterinary*; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D002045:Bupivacaine / Q000008:administration & dosage / Q000494:pharmacology*; D057785:Catheters; D018592:Cross-Over Studies; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D012756:Sheep
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine