LAUSR

BACKGROUND Liposomal local anaesthetic solutions may provide extended duration analgesia postoperatively but have not been assessed following intra-peritoneal local infiltration in any species. OBJECTIVES To evaluate two doses of 1.33% liposomal bupivacaine (LB) versus 0.75% bupivacaine HCL (BHCl) for analgesia following laparoscopic ovariectomy in mares. STUDY DESIGN Prospective cohort study. METHODS Fifteen healthy Quarter Horse mares (age 2-20 years) with normal bilateral ovarian palpation and appearance were enrolled. Horses were restrained in standing stocks and administered an α-2 agonist, butorphanol, and flunixin meglumine, followed by a variable rate infusion of sedation with α-2 agonists. Bilateral paralumbar fossa ovariectomies were performed. Treatment with either 30 mL 0.75% BHCl followed by 20 or 40mL LB 13.3% (LB20, LB40) volume expanded with saline to 80mL total (n=6/group) or 80mL BHCl alone (n=3, BCHL) was infused around incision sites and each mesovarium (LB or BHCl) prior to ovariectomy. Horses were monitored 72h by physical examination, algometry, and pain scoring (Composite Pain Scale by Bussieres et al., Horse Grimace Scale). Abdominocentesis with peritoneal fluid analysis was performed at 72h. RESULTS Analgesia achieved with all treatment protocols allowed completion of ovariectomy procedures. Pressure algometry scores were lower in BHCl-treated horses versus both LB groups overall. Pain scores were improved with LB treated horses in a dose-dependent fashion (Horse Grimace Scale scores LB40