Development of a scale to evaluate postoperative pain in dogs
Firth, A.M.; Haldane, S.L.
Journal of the American Veterinary Medical Association 214(5): 651-659
1999
ISSN/ISBN: 0003-1488 PMID: 10088012 Document Number: 498681
A pain assessment scale was developed for dogs, which incorporated physiological data (heart and respiratory rates) and behavioral responses (response to palpation, activity, mental status, posture, and vocalization). This pain scale was then applied to a study in which dogs were allocated to 2 groups, depending on the type of medication administered (acepromazine maleate only or acepromazine and butorphanol) before induction of general anaesthesia. 36 dogs undergoing routine ovariohysterectomy and 12 dogs undergoing general anaesthesia only were assessed. The 36 dogs that had ovariohysterectomy were allocated to 3 groups, members of which received butorphanol, carprofen, or no analgesic after surgery. Dogs were scored for signs of pain and videotaped at 0, 1, 2, 4, 6, 8, 12, and 18 h after surgery by an assessor who was blinded to the groups. Results were analysed for significant differences in pain scores for single categories and total pain scores among groups. Video segments were scrambled and then scored by a second external assessor to test the repeatability of the results, using the pain assessment scale. Mean total pain scores were significantly different between the group of dogs that underwent general anaesthesia only and each group of dogs that underwent general anaesthesia and surgery. Pain scores for the analgesic-treatment groups reflected the known onset and duration of action of the analgesic used. Agreement between the internal and external assessors was excellent and indicated high precision between the 2 assessors for the population of dogs as a whole. It is concluded that behavioural and physiological measurements can be used reliably to evaluate degree of pain in dogs during the postoperative period and their response to analgesics.