title: Clinical and pharmacokinetic effects of regional or general anaesthesia on intravenous regional limb perfusion with amikacin in horses.
abstract: BACKGROUND
  Antimicrobial i.v. regional limb perfusion (IV-RLP) is clinically performed on anaesthetised or sedated horses with or without regional anaesthesia. To date, no scientific data are available on the clinical and pharmacokinetic effects of these anaesthetic protocols on antimicrobial IV-RLP, which is believed to result in better tourniquet efficiency due to decreased movement.
  
  
  OBJECTIVE
  To determine the effects of regional or general anaesthesia on the clinical and synovial pharmacokinetic parameters of amikacin administered by IV-RLP to horses.
  
  
  METHODS
  Experimental crossover study.
  
  
  METHODS
  Eight healthy horses received 4 treatments of amikacin IV-RLP in a randomised, blinded, crossover design: standing sedation without regional anaesthesia (CNT); standing sedation with i.v. regional anaesthesia; standing sedation with perineural regional anaesthesia (PNA); or general anaesthesia. Synovial fluid amikacin concentrations were measured over 24 h and regional pharmacokinetic parameters calculated. Heart and respiratory rates, visual analogue scale of discomfort, number of times the limb was lifted and number of additional sedations administered were recorded. Analysis of variance crossover analysis was applied with significance level at P < 0.05.
  
  
  RESULTS
  Amikacin concentrations and regional pharmacokinetic parameters did not differ significantly among treatments. Visual analogue scores (mean ± s.d.) were significantly lower with PNA (19 ± 15) vs. i.v. regional anaesthesia (69 ± 36) or CNT (81 ± 13; P < 0.001). Significantly less lifting of the limb (mean ± s.d.) occurred with PNA (20 ± 20) vs. CNT (54 ± 22; P < 0.04).
  
  
  CONCLUSIONS
  Perineural regional anaesthesia before IV-RLP was most effective in providing comfort to standing, sedated horses without significantly affecting the regional pharmacokinetic parameters of amikacin. High variability of synovial amikacin concentrations was present. The use of general anaesthesia for IV-RLP is not justified based on this study.
authors.affiliation: Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, South Africa.
authors.forename: A T
authors.initials: AT
authors.lastname: Mahne
authors.forename: E
authors.initials: E
authors.lastname: Rioja
authors.forename: H J
authors.initials: HJ
authors.lastname: Marais
authors.forename: N F
authors.initials: NF
authors.lastname: Villarino
authors.forename: L M
authors.initials: LM
authors.lastname: Rubio-Martinez
mesh_terms: D000583:Amikacin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000765:Anesthesia, Conduction / Q000662:veterinary*; D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D005260:Female; D006736:Horses / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D000900:Anti-Bacterial Agents; D000583:Amikacin
keywords: amikacin; general anaesthesia; horse; pharmacokinetics; regional anaesthesia; regional limb perfusion