title: Effects of continuous rate infusion of butorphanol in isoflurane-anesthetized calves.
abstract: OBJECTIVE
  To assess the hemodynamic changes and bispectral index (BIS) following administration of a continuous rate infusion (CRI) of butorphanol in isoflurane-anesthetized calves.
  
  
  METHODS
  Eight calves weighing 110 ± 12 kg were included in the study. Anesthesia was induced with 5% isoflurane in O2 delivered via face mask and maintained with end-tidal concentration of 1.4%. IPPV was set to a peak inspiratory airway pressure of 15 cmH2O and respiratory rate of six breaths minute-1. Forty minutes after the start of anesthetic maintenance, 0.1 mg kg-1butorphanol was administered intravenously, followed by a CRI of 20 µg kg-1 minute-1. Hemodynamic variables and BIS were recorded before butorphanol administration (T0), and at 10, 20, 40 and 80 minutes following the CRI. Anesthesia was discontinued after the last recording and the calves were allowed to recover. The time to sternal recumbency (SRE) and standing (ST) were evaluated.
  
  
  RESULTS
  There were no significant differences between the moments in all hemodynamic variables and BIS. The time to SRE and ST was 9 ± 5 and 14 ± 7 minutes, respectively.
  
  
  CONCLUSIONS
  The continuous rate infusion did not produce clinically relevant changes in hemodynamic or bispectral index values compared to baseline in mechanically ventilated and unstimulated calves anesthetized at 1.4% isoflurane.
authors: Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Campo Grande, MS, Brazil.
authors: Marcelo Augusto de
authors: MA
authors: Araújo
authors: Department of Veterinary Medicine, Faculty Integrated, Campo Mourao, PR, Brazil.
authors: Verônica Batista de
authors: VB
authors: Albuquerque
authors: Faculty of Veterinary Medicine, São Paulo State University, Araçatuba, SP, Brazil.
authors: Maurício
authors: M
authors: Deschk
authors: Faculty of Veterinary Medicine, UNESP, Araçatuba, SP, Brazil.
authors: Thomas Alexander
authors: TA
authors: Trein
authors: Department of Veterinary Medicine, Faculty of Veterinary Medicine and Animal Science, UFMS, Campo Grande, MS, Brazil.
authors: Fabrício de Oliveira
authors: Fde O
authors: Frazílio
authors: Department of Clinical, Surgery and Animal Reproduction, Faculty of Veterinary Medicine, UNESP, Araçatuba, SP, Brazil.
authors: Paulo Sergio Patto dos
authors: PS
authors: Santos
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000769:Anesthesia, Inhalation / Q000662:veterinary; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002077:Butorphanol / Q000008:administration & dosage*; D002417:Cattle; D003243:Consciousness / Q000187:drug effects; D056805:Consciousness Monitors; D006439:Hemodynamics / Q000187:drug effects*; D007262:Infusions, Intravenous / Q000662:veterinary*; D007530:Isoflurane / Q000008:administration & dosage*; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D007530:Isoflurane; D002077:Butorphanol