Use of the University of Melbourne Pain Scale to evaluate two post-surgical analgesia protocols in female dogs undergoing mastectomy

Abstract

Breast tumors in dogs comprise about 52% of neoplasms in dogs. Complete surgical removal, called mastectomy, is considered the treatment of choice. Postoperative pain for this procedure can be classified as moderate to severe, therefore requiring treatment with drugs that minimize pain. Preemptive analgesia is a method that consists of administering medications before painful stimulus and, thus, has stood out among analgesic protocols. Scales capable of evaluating pain in animals arose in view of the difficulty in its recognition in Veterinary Medicine. The pain scale of the University of Melbourne (UMPS) consists of the assessment of specific physiological and behavioral parameters related to pain, increasing its sensitivity and specificity. Therefore, the present study aimed to evaluate the effectiveness of two different preemptive analgesia protocols in controlling postoperative pain in dogs undergoing mastectomy, using UMPS. For this, the research included 16 female patients who were randomly divided into two groups (G1 and G2). The G1 group regarding the preemptive analgesia protocol with firocoxib associated with the transdermal fentanyl patch, was composed of 8 females. Thus, the remaining 8 females constituted the G2 group receiving preemptive analgesia with carprofen associated with transdermal fentanyl. In the postoperative period, patients were evaluated by applying the UMPS in 5 stages (T1, T2, T3, T12 and T24). The analgesic rescue was only carried out when the evaluation reached a score higher than 13. Therefore, among the 16 female dogs who participated in the research, 11 of them (68.75%) demonstrated adequate pain control, therefore, there was no need for rescue, 4 patients (25%) required analgesic rescue and 1 patient (6.25%) was disqualified from the research. However, it is concluded that the Pain Scale at the University of Melbourne is a good method for assessing the degree of pain in dogs and that transdermal fentanyl patch (Durogesic®) demonstrated good performance in pain control in association with both anti-inflammatory drugs , as long as it is in total adherence to the skin surface.