title: The effect of intravenous lidocaine infusion on bronchoalveolar lavage cytology in equine recurrent airway obstruction.
abstract: BACKGROUND
  Lidocaine decreases neutrophilic inflammation in models of acute lung injury and decreases inflammation in asthmatic patients. Neutrophilic bronchiolitis develops in recurrent airway obstruction (RAO), but it remains unknown if lidocaine infusion decreases neutrophil migration into the airways.
  
  
  OBJECTIVE
  Lidocaine decreases neutrophilic inflammation as measured in BALF in RAO-affected horses.
  
  
  METHODS
  Six RAO-susceptible horses in remission.
  
  
  METHODS
  In a randomized cross-over design, horses received lactated Ringer's solution (LRS) IV or lidocaine hydrochloride IV with a minimum of 4 weeks at pasture between treatments. Treatments were delivered as continuous infusions beginning 4 hours before and for 68 hours during exposure to hay and straw challenge. Clinical score (CS, grade 0-8), maximal change in pleural pressure (∆Ppl(max) ), and bronchoalveolar lavage fluid (BALF) cytology were measured at baseline and the end of challenge (day 4). Plasma lidocaine concentrations were monitored daily.
  
  
  RESULTS
  At baseline, there were no significant differences in variables between treatments. Plasma lidocaine concentration was consistently > 1100 ng/mL. After challenge, CS increased significantly [baseline: 2/8 (2-3), [median (interquartile range)]; day 4: 4/8 (4-5) P = .0006] as did ∆Ppl(max) [baseline: 3.6 (2.63-4.95) cmH(2) 0; day 4: 9.62 (6.5-16) P = .0036], but there was no difference between treatments. Percentage of neutrophils was not different between treatments, but lidocaine infusion significantly increased BALF total cells [baseline: LRS 2.18 ± 0.82 × 10(5) cells/mL (mean ± SD), lidocaine 1.6 ± 0.3 × 10(5) , day 4: LRS 2.0 ± 0.88 × 10(5) , lidocaine 4.4 ± 2 × 10(5) (P = .0045)].
  
  
  CONCLUSIONS
  Lidocaine does not decrease neutrophilic inflammation in RAO.
authors.affiliation: Equine Pulmonary Laboratory, Large Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA. wilso716@cvm.msu.edu
authors.forename: M E
authors.initials: ME
authors.lastname: Wilson
authors.forename: C
authors.initials: C
authors.lastname: Berney
authors.forename: A L
authors.initials: AL
authors.lastname: Behan
authors.forename: N E
authors.initials: NE
authors.lastname: Robinson
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology*; D018592:Cross-Over Studies; D004333:Drug Administration Routes; D006734:Horse Diseases / Q000188:drug therapy* / Q000473:pathology; D006736:Horses; D007249:Inflammation / Q000188:drug therapy / Q000662:veterinary*; D008012:Lidocaine / Q000008:administration & dosage / Q000627:therapeutic use*; D008173:Lung Diseases, Obstructive / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D061567:Voltage-Gated Sodium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use
chemical_list: D061567:Voltage-Gated Sodium Channel Blockers; D008012:Lidocaine