Evaluation of the analgesic potential of serratus block associated with tap block in female dogs undergoing mastectomy.

Breast tumors are common in female dogs, and in most cases, unilateral mastectomy is the surgical technique. This procedure poses a considerable risk for the development of post-surgical chronic pain. Therefore, the animal must have a good analgesic plan during the intraoperative period. This study aimed to evaluate the analgesic potential of the serratus plane (SP) block when combined with the transversus abdominis plane (TAP) block during the intraoperative and postoperative periods in female dogs undergoing mastectomy. Eighteen female dogs, aged 5-15 years and weighing 4-77 lbs, with mammary tumors staged I-III, were referred for total unilateral mastectomy. These dogs were pre-medicated with 0.03 mg/kg intramuscular acepromazine, an anesthetic was induced with propofol, and maintained with isoflurane. The dogs were divided into two groups: in 10 dogs, TAP blocks were performed with a volume of 0.4 mL/kg, combined with SP blocks with a volume of 0.4 mL/kg of 0.25% bupivacaine intraoperatively, before starting surgery, and in another eight dogs, tumescent anesthesia was performed with a cold solution containing lactated Ringer's, 2% lidocaine without vasoconstrictor, and adrenaline in 15 mL/kg intraoperatively. During data collection, analysis, interpretation of results, and subject follow-up, no group exhibited a response to nociceptive stimuli during the intraoperative period. In the postoperative period, only one dog from group 1 presented with a score greater than 5, and a slight delay in anesthetic recovery was observed in dogs from group 2. The evaluation of parameters during and after surgery, combined with the low need for analgesics in most female dogs, indicated that the combination of TAP and SP blocks was effective for analgesic control. In conclusion, this combination is an alternative to promote analgesia and favor recovery in female dogs undergoing mastectomy.