Evaluation of lidocaine administration into the ovarian pedicle for the control of intraoperative and early postoperative pain during ovariohysterectomy in dogs.

OBJECTIVE: To evaluate effects of lidocaine 2% administration into the ovarian pedicle on intraoperative nociception and early postoperative pain in dogs undergoing ovariohysterectomy. STUDY DESIGN: Prospective, randomized, blinded clinical study. ANIMALS: A total of 20 healthy adult female dogs of different breeds. METHODS: Dogs were premedicated with acepromazine (0.02 mg kg-1) and morphine (0.5 mg kg-1) intramuscularly, anesthesia induced with propofol and maintained with isoflurane. Dogs were randomly assigned to be administered 2 mL of saline (group S) or lidocaine 2% (group L) into the mesovarium (1 mL each side). Heart rate (HR) and noninvasive systemic arterial pressure were recorded before surgery (T0), before (T1) and during ligation of the right ovarian pedicle (T2), before (T3) and during ligation of the left ovarian pedicle (T4). Rescue treatment (propofol) was administered if HR or systolic arterial pressure (SAP) increased by 20% compared with the previous time point. Pain, assessed with the Glasgow Composite Measure Pain Scale-Short Form (CMPS-SF) was recorded before premedication (baseline) and after extubation. Administration of postoperative rescue analgesia was recorded. RESULTS: In group S, HR was higher at T2 than T1 (112 ± 18 versus 89 ± 21 beats minute-1, p = 0.001) There were no significant differences between treatments at any time. SAP was higher at T2 than T1 in group S (110 ± 12 versus 100 ± 10 mmHg, p = 0.031). SAP was higher in group S than group L at T3 (113 ± 12 and 91 ± 10 mmHg, respectively, p = 0.001). No dogs required propofol intraoperatively. All dogs required postoperative rescue analgesia. Compared with baseline, CMPS-SF increased 60 minutes after extubation (group S; p = 0.019, group L; p = 0.043). CONCLUSIONS AND CLINICAL RELEVANCE: Administration of lidocaine 2% into the mesovarium did not reduce intraoperative nociception and did not improve postoperative analgesia.

Effects of dissociative anesthesia opioid-free protocols combined with local anesthesia, with or without flumazenil or atipamezole postoperatively, for orchiectomy in cats.

OBJECTIVE: To evaluate the anesthetic effects of two drug combinations with local anesthesia, with or without postoperative antagonists, for orchiectomy in cats. STUDY DESIGN: Prospective, randomized blinded clinical study. ANIMALS: A total of 64 healthy cats. METHODS: Cats were assigned to four equal groups: ketamine (5 mg kg-1) and dexmedetomidine (10 µg kg-1) were administered intramuscularly (IM), followed postoperatively with intravenous (IV) saline (5 mL; group KDS) or atipamezole (50 µg kg-1; group KDA); and ketamine (14 mg kg-1) with midazolam (0.5 mg kg-1) and acepromazine (0.1 mg kg-1) IM, with postoperative IV saline (5 mL; group KMAS) or flumazenil (0.1 mg kg-1; group KMAF). Lidocaine (2 mg kg-1) was divided between subcutaneous and intratesticular injection. Physiologic variables were recorded at time points during anesthesia. Ketamine rescue dose was recorded. The degree of sedation and the quality of recovery were evaluated postoperatively. RESULTS: Time to loss of pedal reflex was longer in groups KMAS and KMAF than in groups KDS and KDA (p = 0.010). Total rescue dose of ketamine was higher in KMAS and KMAF than in KDS and KDA (p = 0.003). Heart rate (HR) during anesthesia was higher in KMAS and KMAF than in KDS and KDA (p = 0.001). Times to head up (p = 0.0005) and to sternal recumbency (p = 0.0003) were shorter in KDA than in KDS, KMAS and KMAF. Lower sedation scores were assigned sooner to KDA than KDS, KMAS and KMAF (p < 0.001). Recovery quality scores were good in all groups. CONCLUSIONS AND CLINICAL RELEVANCE: Both anesthetic protocols allowed the performance of orchiectomy. Groups KMAS and KMAF required higher rescue doses of ketamine before injecting lidocaine. HR and oscillometric systolic pressure were minimally changed in groups KD and tachycardia was recorded in groups KMA. Only atipamezole shortened the anesthetic recovery.