Abstract
Objective: To compare post-operative pain in cats after alfaxalone or ketamine- medetomidine anaesthesia for ovariohysterectomy (OHE) and physiologic parameters during and after surgery.
Study design: Prospective ‘blinded’ randomized clinical study.
Animals: Twenty-one healthy cats.
Methods: Cats were assigned randomly into two groups: Group A, anaesthesia was induced and maintained with alfaxalone [5 mg kg−1 intravenously (IV) followed by boli (2 mg kg−1 IV); Group MK, induction with ketamine (5 mg kg−1 IV) after medetomidine (30 μg kg−1 intramuscularly (IM)], and maintenance with ketamine (2 mg kg−1 IV). Meloxicam (0.2 mg kg−1 IV) was administered after surgery. Basic physiological data were collected. At time T = −2, 0, 0.5, 1, 2, 4, 6, 8, 12, 16, 20, and 24 hours post-operatively pain was assessed by three methods, a composite pain scale (CPS; 0–24 points), a visual analogue scale (VAS 0–100 mm), and a mechanical wound threshold (MWT) device. Butorphanol (0.2 mg kg−1 IM) was administered if CPS was scored ≥13. Data were analyzed using a general linear model, Kruskal–Wallis analyses, Bonferroni-Dunn test, unpaired t-test and Fisher's exact test as relevant. Significance was set at p < 0.05.
Results: VASs were significantly higher at 0.5, 1, 2, 4, and 20 hours in group A; MWT values were significantly higher at 8 and 12 hours in group MK. Post-operative MWT decreased significantly compared to baseline in both groups. There was no difference in CPS at any time point. Five cats required rescue analgesia (four in A; one in MK).
Conclusion and clinical relevance: Anaesthesia with ketamine-medetomidine was found to provide better post-surgical analgesia than alfaxalone in cats undergoing OHE; however, primary hyperalgesia developed in both groups. Alfaxalone is suitable for induction and maintenance of anaesthesia in cats undergoing OHE, but administration of additional sedative and analgesic drugs is highly recommended.
Kalchofner Guerrero, Karin S