Use of lidocaine as a prokinetic agent cannot be supported by this study in normal horses; however, results may differ in clinically affected horses.

Lidocaine is administered as an intravenous infusion to horses for a variety of reasons, but no study has assessed plasma lidocaine concentrations during a 12-h infusion to horses. The purpose of this study was to evaluate the plasma concentrations and pharmacokinetics of lidocaine during a 12-h infusion to postoperative horses. A second purpose of the study was to evaluate the in vitro plasma protein binding of lidocaine in equine plasma. Lidocaine hydrochloride was administered as a loading dose, 1.3 mg/kg over 15 min, then by a constant rate IV infusion, 50 microg/kg/min to six postoperative horses. Lidocaine plasma concentrations were measured by a validated high-pressure liquid chromatography method. One horse experienced tremors and collapsed 5.5 h into the study. The range of plasma concentrations during the infusion was 1.21-3.13 microg/mL. Lidocaine plasma concentrations were significantly increased at 0.5, 4, 6, 8, 10 and 12 h compared with 1, 2 and 3 h. The in vitro protein binding of lidocaine in equine plasma at 2 microg/mL was 53.06+/-10.28% and decreased to 27.33+/-9.72% and 29.52+/-6.44% when in combination with ceftiofur or the combination of ceftiofur and flunixin, respectively. In conclusion, a lower lidocaine infusion rate may need to be administered to horses on long-term lidocaine infusions. The in vitro protein binding of lidocaine is moderate in equine plasma, but highly protein bound drugs may displace lidocaine increasing unbound concentrations and the risk of lidocaine toxicity.

The purpose of this article is to review the veterinary literature for various surgical procedures of the equine upper respiratory tract in an effort to evaluate the evidence supporting various therapies. This article focuses on the therapeutic benefit from more widely occurring conditions, such as laryngeal hemiplegia, dorsal displacement of the soft palate, arytenoid chondritis, and epiglottic entrapment.

Nineteen-gauge needles significantly increase the risk of joint contamination with hair compared to 20 g needles; non-lubricated 19 g needles have the greatest risk. All other needle types tested in this study have similar risks for tissue and hair contamination after arthrocentesis.

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