The influence of demeanor on scores from two validated feline pain assessment scales during the perioperative period

Objective To evaluate the effects of demeanor on validated pain assessment scales. Study design Prospective, blind, clinical trial. Animal population Thirty three adult domestic cats scheduled for orchiectomy. Methods Cats were assessed for pain pre (baseline) and 1, 2, 4 hours postoperatively using two validated pain scales [Composite Measures Pain Scale-Feline (rCMPS-F) and UNESP-Botucatu multidimensional composite pain scale (psychomotor and pain expression subscales; U-B MCPS-psych and -painex)], and a demeanor scale. Return of sternal recumbency and postoperative feeding were recorded. Anesthesia consisted of a single intramuscular injection of dexmedetomidine-ketamine-hydromorphone with intratesticular lidocaine and atipamezole and meloxicam postoperatively. Following data collection, cats were assigned to two groups based on baseline demeanor scores (LO <= 5/21, 18 cats; HI >= 6/21, 15 cats) and data from each group compared. Results Baseline demeanor predicted pain scores with the U-B MCPS-psych scale: baseline [LO 0 (0-0), HI 2 (0-6), p = 0.0005], 1 hour [LO 1 (0-5), HI 3 (1-5), p = 0.02], and 4 hours [LO 0 (0-2), HI 1 (0-6), p = 0.01]. A similar pattern was observed with the rCMPS-F. This resulted in more crossings of the analgesic intervention threshold in the HI group: U-B UNESP-psych (9 versus 1, p = 0.005) and rCMPS-F (23 versus 3, p < 0.0001). In contrast, U-B MCPS-painex scores did not differ between LO/HI groups: baseline (p > 0.99), 1 hour (p = 0.34), 2 hours (p > 0.99) and 4 hours (p = 0.31). LO cats ate sooner (61% versus 33% by 1 hour, p < 0.0001) despite similar times to sternal recumbency (p = 0.48). Conclusions and clinical relevance Demeanor affected pain assessment with U-B UNESP-psych and rCMPS-F scales, but not U-B UNESP-painex scale. Demeanor had a significant effect on postoperative feeding. These data highlight the potential for demeanor to confound pain assessment.