title: Analgesic and systemic effects of ketamine, xylazine, and lidocaine after subarachnoid administration in goats.
abstract: OBJECTIVE
  To determine the effects of ketamine hydrochloride, xylazine hydrochloride, and lidocaine hydrochloride after subarachnoid administration in goats.
  
  
  METHODS
  6 healthy goats.
  
  
  METHODS
  In each goat, ketamine (3 mg/kg), xylazine (0.1 mg/kg), lidocaine (2.5 mg/kg), and saline (0.9% NaCI) solution were injected into the subarachnoid space between the last lumbar vertebra and first sacral vertebra (time 0). Analgesic, ataxic, sedative, cardiovascular, and respiratory effects and rectal temperature were evaluated before (baseline) and 2, 5, 10, 15, and 30 minutes after administration and at 30-minute intervals thereafter as needed.
  
  
  RESULTS
  Administration of anesthetics induced varying degrees of analgesia. Onset of the analgesic effect was more delayed for xylazine (mean +/- SD, 9.5 +/- 2.6 minutes) than for ketamine (6.7 +/- 2.6 minutes) or lidocaine (3.5 +/- 1.2 minutes). Duration of analgesia induced by xylazine (88.3 +/- 15 minutes) was twice as long as the duration of analgesia induced by ketamine (48.8 +/- 13.5 minutes) but similar to that induced by lidocaine (66.5 +/- 31 minutes). Xylazine induced bradycardia, whereas ketamine caused a nonsignificant increase in heart rate. Xylazine induced a reduction in arterial pressure, whereas ketamine or lidocaine did not affect arterial pressure.
  
  
  CONCLUSIONS
  Subarachnoid administration of xylazine in goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flanks, and caudodorsal rib areas than administration of ketamine or lidocaine. However, xylazine caused bradycardia and respiratory depression. Additional studies are needed to determine whether the analgesia would be sufficient to allow clinicians to perform surgical procedures.
authors.affiliation: Department of Veterinary Medicine-Surgery and Anesthesiology, Faculty of Veterinary Medicine, Federal University of Mato Grosso do Sul State, Avenida Filinto Müller, Campo Grande, CEP 79070-900, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: DeRossi
authors.forename: Alexandre Lopes
authors.initials: AL
authors.lastname: Junqueira
authors.forename: Marcelo Paixão
authors.initials: MP
authors.lastname: Beretta
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000698:Analgesia / Q000662:veterinary; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000494:pharmacology*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001259:Ataxia / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation / Q000662:veterinary; D006041:Goats / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D007278:Injections, Spinal / Q000662:veterinary; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D013346:Subarachnoid Space; D014991:Xylazine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000316:Adrenergic alpha-Agonists; D000778:Anesthetics, Dissociative; D000779:Anesthetics, Local; D014991:Xylazine; D007649:Ketamine; D008012:Lidocaine