Objective: This study aimed to determine whether an infiltrative block with liposomal bupivacaine was associated with less rescue analgesia administration and lower pain scores than a bupivacaine splash block after ovariohysterectomy in dogs.

Animals: Eligible dogs included those that were spayed as part of a veterinary teaching laboratory. Dogs were up to 7 years old and otherwise healthy. A total of 136 dogs were analyzed.

Methods: All dogs underwent ovariohysterectomy performed by veterinary students. Dogs received hydromorphone and acepromazine premedication, propofol induction, isoflurane maintenance, and an NSAID. Dogs were randomly allocated to receive either a splash block with standard bupivacaine or an infiltrative block with liposomal bupivacaine for incisional analgesia. Postoperatively, all dogs were assessed by a blinded evaluator using the Colorado State University-Canine Acute Pain Scale (CSU-CAPS) and Glasgow Composite Measures Pain Scale-Short Form (GCPS-SF). Dogs received rescue analgesia with buprenorphine if they scored ≥ 2 on the CSU-CAPS scale.

Results: Dogs that received liposomal bupivacaine had a significantly lower incidence of (P = .04) and longer time to (P = .03) administration of rescue analgesia. There was an overall time-averaged significant difference between groups for CSU-CAPS (P = .049) and GCPS-SF scores (P = .015), with dogs in the bupivacaine group being more likely to have an elevated pain score at some point for both scales.

Clinical relevance: The use of liposomal bupivacaine in an infiltrative block may decrease the need for rescue analgesia in dogs undergoing ovariohysterectomy compared to a bupivacaine splash block.