Randomised, prospective, blinded, clinical trial of opioid-free injectable anaesthesia with or without multimodal analgesia in kittens undergoing ovariohysterectomy

Abstract

Objectives This study compared an opioid-free injectable anaesthetic protocol with or without multimodal analgesia in kittens undergoing ovariohysterectomy. Methods In this prospective, randomised, blinded, clinical trial, 29 healthy kittens (mean ± SD weight 1.55 ± 0.46 kg; aged 10 weeks to 6 months) were included. Anaesthesia was performed with an intramuscular injection of ketamine (4 mg/kg), dexmedetomidine (40 μg/kg) and midazolam (0.25 mg/kg). In the multimodal group (MMG), cats (n = 14) received meloxicam (0.1 mg/kg SC) and intraperitoneal bupivacaine 0.25% (2 mg/kg), whereas the same volume of saline was administered in the control group (CG; n = 15). Atipamezole (0.4 mg/kg IM) was given 15 mins after ovariohysterectomy. Postoperative pain was assessed using the UNESP-Botucatu multidimensional feline pain assessment scale – short form. Rescue analgesia (buprenorphine 0.02 mg/kg IM in MMG/CG and meloxicam 0.1 mg/kg SC in CG) was administered if pain scores were ⩾4/12. Soft food intake (after 2 and 60 mins) was evaluated at specific time points postoperatively. Statistical analyses were performed with linear models and post-hoc pairwise comparison with Benjamini–Hochberg corrections ( P <0.05). Results The prevalence of rescue analgesia was higher in the CG (n = 15/15) than the MMG (n = 1/14; P <0.001). Pain scores at 1 h, 2 h and 4 h postoperatively were higher in the CG (4.1 ± 2.8, 4.8 ± 3.0 and 5.3 ± 1.2, respectively) than in the MMG (1.6 ± 1.0, 1.1 ± 1.0 and 0.9 ± 0.8, respectively; P <0.001). Food intake (%) at 1 h postoperatively was higher in the MMG after 2 and 60 mins (10.4 ± 9 and 71.9 ± 29, respectively) than in the CG (1.4 ± 2 and 13.9 ± 7, respectively; P <0.001). Conclusions and relevance This opioid-free protocol using multimodal analgesia produced adequate postoperative pain relief, while almost eliminating the need for rescue analgesia in kittens undergoing ovariohysterectomy. Pain decreased food intake.

An ethogram of acute pain behaviors in cats based on expert consensus

“…Changes in feeding behavior were considered reliable for assessing pain by expert consensus [ 20 ], although it requires knowledge of prior feeding patterns. ‘Not eating/no interest to food’ was considered highly relevant to pain-related behavior in our ethogram and reduced food intake (e.g., after dental surgical procedures) could be of clinical relevance as pain indicator in cats [ 13 , 44 ]. A recent study compared food intake in kittens (i.e., 10 weeks to 6 months of age) undergoing ovariohysterectomy using an opioid-free anesthetic protocol with or without multimodal analgesia.…”

“…A recent study compared food intake in kittens (i.e., 10 weeks to 6 months of age) undergoing ovariohysterectomy using an opioid-free anesthetic protocol with or without multimodal analgesia. Food intake (%) was significantly higher in non-painful than painful cats when it was evaluated for 2 minutes (15.2 vs 4.2, respectively) and 60 minutes (58.9 vs 29.9, respectively) postoperatively [ 44 ]. ‘Difficulty grasping or holding food’ was observed more frequently in painful when compared to non-painful cats undergoing multiple dental extractions in a multidisciplinary study [ 13 ].…”

Construct validity, responsiveness and reliability of the Feline Grimace Scale in kittens

“…The present study was conducted in parallel with a prospective, randomized, blinded clinical trial comparing an opioid-free injectable anesthetic protocol with or without multimodal analgesia in kittens undergoing OVH. 13 The study protocol was approved by the Comité d’éthique de l’utilisation des animaux (Animal Use Ethics Committee) of the Faculty of Veterinary Medicine, Université de Montréal (protocol 21-Rech-2132), performed in accordance with the Canadian Council on Animal Care and reported according to the ARRIVE guidelines. 14…”

2022 WSAVA guidelines for the recognition, assessment and treatment of pain

“…Kittens in the multi-modal group were administered meloxicam preoperatively and intraperitoneal bupivacaine intraoperatively. Prevalence of rescue analgesia was higher in the control group (n=15/15) than the multi-modal group (n=1/14) (Malo et al 2022). Reviews on the use of opioids in dogs and cats including clinical guidance, and misconceptions and controversies related to opioid analgesia are recommended as further reading (Steagall et al 2014, Bortolami & Love 2015, Simon & Steagall 2017, Kongara 2018).…”