Liposomal bupivacaine is both safe and effective when administered via local infiltration at surgical site and mesovarium for laparoscopic ovariectomy in mares

Liposomal local anaesthetic solutions may provide extended duration analgesia postoperatively but have not been assessed following intra-peritoneal local infiltration in any species.To evaluate two doses of 1.33% liposomal bupivacaine (LB) versus 0.75% bupivacaine HCL (BHCl) for analgesia following laparoscopic ovariectomy in mares.Prospective cohort study.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.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 LB40LB20BHCL; Composite Pain Scale scores LB40BHCL, LB20BHCL, BHCL and LB20 did not differ). Peritoneal fluid total protein was lower in LB40 vs LB20 and BHCL horses. No complications from LB administration were appreciated.Small patient sample size, lack of follow-up past 72h or histopathology.Analgesia duration was extended, and pain scores improved postoperatively with LB vs. BHCl in a dose-dependent fashion. Further clinical evaluation of extended duration local anaesthetics in horses for improved postoperative pain management is warranted. This article is protected by copyright. All rights reserved.