Development of a behaviour-based measurement tool with defined intervention level for assessing acute pain in cats

OBJECTIVES: To develop a composite measure pain scale tool to assess acute pain in cats and derive an intervention score. METHODS: To develop the prototype composite measure pain scale-feline, words describing painful cats were collected, grouped into behavioural categories and ranked. To assess prototype validity two observers independently assigned composite measure pain scale-feline and numerical rating scale scores to 25 hospitalised cats before and after analgesic treatment. Following interim analysis the prototype was revised (revised composite measure pain scale-feline). To determine intervention score, two observers independently assigned revised composite measure pain scale-feline and numerical rating scale scores to 116 cats. A further observer, a veterinarian, stated whether analgesia was necessary. RESULTS: Mean +/- sd decrease in revised composite measure pain scale-feline and numerical rating scale scores following analgesia were 2.4 +/- 2.87 and 1.9 +/- 2.34, respectively (95% confidence interval for mean change in revised composite measure pain scale-feline between 1.21 and 3.6). Changes in revised composite measure pain scale-feline and numerical rating scale were significantly correlated (r=0.8) (P<0001). Intervention level score of >= 4/16 was derived for revised composite measure pain scale-feline (26.7% misclassification) and >= 3/10 for numerical rating scale (14.5% misclassification). CLINICAL SIGNIFICANCE: A valid instrument with a recommended analgesic intervention level has been developed to assess acute clinical pain in cats that should be readily applicable in practice.