Bupivacaine injection reduces pain medicine after dog eye removal

Abstract

OBJECTIVE: To evaluate the effectiveness of bupivacaine liposomal injectable suspension (BLIS), administered as a peri-incisional eyelid block, in reducing postoperative pain when compared to saline placebo in dogs undergoing enucleation. METHODS: Client-owned dogs undergoing enucleation were enrolled from April 2021 until January 2023 and randomly assigned to receive either BLIS or saline. Dogs were premedicated with hydromorphone and acepromazine, induced with propofol, and maintained with isoflurane. Following subconjunctival enucleation and immediately prior to incision closure, a peri-incisional injection with BLIS or saline was administered into the subcutaneous eyelid tissues. Pain scoring and algometry of the incision were conducted preoperatively by a masked observer and at 0, 1, 2, 4, 8, 24, 36, 48, and 72 hours postoperatively. Oral meloxicam was administered after the 8-hour time point. Rescue analgesia was given if a pain score ≥ 3 in any category or ≥ 10 total was recorded. RESULTS: 30 dogs completed the study (n = 15 in each treatment group). Dogs receiving BLIS had a significantly lower odds (OR, 0.14) of need for rescue and significantly lower odds (OR, 0.38) of having a higher pain score across the study. Administration of BLIS did not significantly impact mechanical threshold testing results. CONCLUSIONS: Treatment with BLIS reduced the need for rescue analgesia, and these dogs were more likely to have lower pain scores. CLINICAL RELEVANCE: BLIS may be useful as part of a multimodal pain management plan in dogs undergoing enucleation when administered as a peri-incisional eyelid block.