Postoperative analgesia time in dogs submitted to mastectomy and anesthetized with tumescent solutions of lidocaine or ropivacaine

Rocha, Fabiana Del LamaNunes, NewtonSantos, Paula Chiconi Dacunto dosIdo, Cléber KazuoSilva, Paloma do Espírito SantoAidar, Eveline Simões AzenhaSilva, Helen Roberta Amaral daPrada, Tiago Carmagnani

Background: Mastectomy, a procedure with high pain stimulation, is the treatment of choice for bitches with breast cancer. Tumescent anaesthesia is widely used for transoperative and postoperative analgesia in bitches submitted to mastectomy, because facilitates tissue divulsion, also contributing significantly for the rapid recovery of patients. Although, there is no consensus as to which local anesthetic to use and at what concentration it should be used. Herein was investigated which local anesthetics, lidocaine or ropivacaine, when used in tumescent solutions, could provide a more lasting analgesic effect in the postoperative period in bitches submitted to radical unilateral mastectomy. Materials, Methods & Results: Sixteen bitches were sedated with chlorpromazine (0.3 mg/kg) and meperidine (3 mg/kg) followed by anesthesia with propofol and isofluorane. Then, bitches were randomly assigned to two groups (n= 8 each): LG group, infused with 15 mL/kg of tumescence solution containing 0.1% lidocaine; and RG group, infused with 15 mL/kg of tumescence solution with 0.1% ropivacaine. The study was conducted in a double-blind fashion. Control group did not include, because the patients would be submitted to severe or unbearable pain, according to the short-form of the Glasgow pain Scale (CMPS-SF). The heart (HR) and respiratory (ƒ) rates, and systolic blood pressure (SBP) were measured in the pre-operative period and immediately after extubation (Mextub) and at 0.5 h, 1 h, 2 h, 4 h, 8 h, and 12 h after the extubation. Analgesic efficacy was assessed using the CMPS-SF and von Frey filaments. Both groups showed higher means for HR at 0.5 h (167 ± 7 in LG; 170 ± 7 in RG) than at 4 h (117 ± 7 in LG; 120 ± 7 in RG). CMPS-SF revealed higher medians (P = 0.038) at the Mextub and 12 h time points for the LG [5 (3-6) and 1 (0-2)] than for the RG [5 (2-5) and 0 (0-1)]. Discussion: Pain was excluded as a possible explanation...

1. Tumescent local anesthesia
2. Breast neoplasm
3. Pain
4. Local anesthetic
5. Dogs