title: Evaluation of continuous infusion of lidocaine on gastrointestinal tract function in normal horses.
abstract: OBJECTIVE
  To determine the effect of continuous infusion of lidocaine on fecal transit time in normal horses.
  
  
  METHODS
  Experimental randomized cross-over study.
  
  
  METHODS
  Healthy horses (n=6).
  
  
  METHODS
  Barium-filled microspheres were administered to horses by nasogastric intubation and feces were collected every 2 hours for 4 days. A bolus of 2% lidocaine (1.3 mg/kg) was administered randomly, followed by a continuous infusion of lidocaine (0.05 mg/kg/min) for 3 days or an equivalent volume of saline. The washout period was 10 days. Variables assessed included defecation frequency, weight of feces produced, intestinal transit time (number of microspheres observed on radiographs), fecal moisture content, borborygmus score, heart and respiratory rate, and signs of lidocaine toxicity (e.g., ataxia, CNS depression).
  
  
  RESULTS
  During the first 24 hours of lidocaine administration, mean (+/-SD) fecal output (10.8+/-6.9 kg) was decreased compared with controls (15+/-4.9 kg). Mean (+/-SEM) time for passing 50% of the barium-filled microspheres was shorter in controls (42+/-1.13 hours) compared with the lidocaine group (50+/-1.32 hours).
  
  
  CONCLUSIONS
  Continuous infusion of lidocaine increases the transit time of feces in normal horses.
  
  
  CONCLUSIONS
  Clinicians need to be aware of the effects of using a continuous infusion of lidocaine on the transit time of feces in normal horses, with a potential for exacerbating those effects when combined with drugs that decrease motility and in horses with medical colic (e.g., impaction) or where a diagnosis has not been made.
authors.affiliation: William R. Pritchard Veterinary Medical Teaching Hospital and the Comparative Gastroenterology Laboratory, Department of Surgical & Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Rusiecki
authors.forename: Jorge E
authors.initials: JE
authors.lastname: Nieto
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Puchalski
authors.forename: Jack R
authors.initials: JR
authors.lastname: Snyder
mesh_terms: D000818:Animals; D018592:Cross-Over Studies; D005260:Female; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000502:physiology*; D005772:Gastrointestinal Transit / Q000187:drug effects*; D006736:Horses / Q000502:physiology*; D007263:Infusions, Parenteral / Q000662:veterinary; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D011897:Random Allocation; D013997:Time Factors
chemical_list: D008012:Lidocaine