Evaluation of continuous infusion of lidocaine on gastrointestinal tract function in normal horses.
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.
Rusiecki
Karen E
KE
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.
Nieto
Jorge E
JE
Puchalski
Sarah M
SM
Snyder
Jack R
JR
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
D008012:Lidocaine