Objective: To compare efficacy and safety of a continuous rate infusion of detomidine hydrochloride and romifidine hydrochloride for standing elective bilateral laparoscopic ovariectomy in mares.
Study design: Blinded, randomized prospective clinical study.
Animals: Eighteen healthy mares presenting for elective bilateral ovariectomy METHODS: Mares were randomly assigned to one of two sedation protocols. Prior to surgery, baseline head height, heart rate, respiratory rate, and postural sway were recorded. An IV loading dose of α2-agonist (46 μg/kg romifidine or 13.9 μg/kg detomidine) was administered. Standing sedation was maintained with a continuous rate infusion of the respective α2-agonist (126 μg/kg/h romifidine or 37.8 μg/kg/h detomidine). Intraoperative measurements included respiratory rate, heart rate, head height, postural sway, and response to surgical stimulus. Postoperatively, fecal output was recorded, and pain scoring was performed using composite pain score and visual analog scales.
Results: Three of 18 horses required additional α-2 agonists: one detomidine and two romifidine and butorphanol. Head height during surgery was lower (p < .001) in mares receiving detomidine. Postural sway around the vertical axis was greater in mares sedated with detomidine rather than romifidine (p = .013). No differences were detected in intraoperative heart rate, postoperative pain scores or postoperative fecal output between sedation techniques.
Conclusion: Comparable scores for surgical stimulation and sedation were measured in both sedation groups. No differences in postoperative analgesia or manure production were identified.
Clinical significance: Romifidine appears suitable as an alternative to detomidine and may limit ataxia and head drop in sedated horses.
© 2021 American College of Veterinary Surgeons.