Comparação entre técnicas de analgesia distintas em cadelas submetidas à mastectomia unilateral total em um hospital escola: um estudo retrospectivo

Abstract

Mammary tumors are the most prevalent neoplasm in female dogs. The treatment considered the gold standard is mastectomy, a procedure associated with high nociceptive stimulation in the intraoperative period. The proper use of anesthetic and analgesic techniques is important to avoid postoperative pain and decreased quality of life for the patient. The aim of this study was to make a comparison between different analgesia approaches evaluating vital parameters in response to transoperative nociception, and postoperative pain management in dogs submitted to Total Unilateral Mastectomy. The study included 276 anesthetic records of patients submitted to this procedure during 10 years in the Oncology routine of the Veterinary Hospital of UFMG. The data collected were age, weight, breed, analgesic protocol - locoregional blocks (0), continuous rate infusion (1) and locoregional blocks with systemic analgesia by CRI (2), premedication protocol (opioids only - 0, phenothiazines with opioid - 1, or -2 agonist with opioid - 2), induction protocol (propofol and others), use of NSAIDs and analgesics in the postoperative period, and need for trans and postoperative analgesic rescue. In addition to the variables HR, DAP, MAP, SAP, at an interval of 65 minutes, every 5 minutes (T1 to T13), and any cardiac alterations and the treatment implemented. This is a retrospective study. Linear models were adjusted for each response variable. With only significant predictor variables, the main effects of the predictor variables were tested, as well as the interactions. The mean value and its respective 95% confidence interval were then calculated for each group. Sidak's correction was applied in the multiple comparison tests. The mean age of the animals was 11.3 years old (± 2.7), and the weight was 12.3 kg (± 9.9). Mean HR was 98 bpm (± 29), SAP 109 mmHg (± 23), MAP 81 mmHg (± 20) and DAP 64 mmHg (± 19). The most used analgesia was 1, followed by 2 and 0, in that order. The most frequent premedication was 0, followed by 1 and 2, respectively. The ASA analysis showed most of the animals as II and III. Among the occurrences of cardiac alterations, 74.5% had bradycardia, 52.7% tachycardia, 96.4% did not have hypertension, and 85.1% had hypotension. There was a significant association between the premedication protocol and the analgesia protocol. For Bradycardia, the only significant variable was premedication; for Tachycardia, only ASA; for Hypotension, both age and pre medication; for Hypertension, no variable was significant; for tans cirurgic rescues, both MPA and analgesia; for HR, both ASA and time; for SAP, ASA, pre medication and analgesia were significant; for MAP they were ASA and pre medication; in DAP were ASA, pre medication and time. All methods evaluated in the study are similar on controlling nociception during total unilateral mastectomy in dogs. It was not possible to state whether the use of locoregional techniques is more effective in its treatment and whether there was a better quality of recovery in the use of this protocol when compared to systemic analgesia.