Objective To determine if intraperitoneal (IP) and incisional (SC) lidocaine or bupivacaine provide analgesia following ovariohysterectomy (OHE).
Study Design Prospective, randomized, controlled, blinded clinical trial.
Animals Thirty dogs presenting to the Veterinary Teaching Hospital for elective OHE.
Methods Dogs were pre-medicated with acepromazine and butorphanol, induced with thiopental and maintained with isoflurane. They were randomly assigned to three groups: 10 received 8.8 mg kg−1 2% lidocaine with epinephrine IP (LID); 10 received 4.4 mg kg−1 0.75% bupivacaine IP (BUP); and 10 received 0.9% saline IP (SAL) upon completion of OHE. All IP doses were standardized to 0.88 mL kg−1 with saline. An additional 2 mL of undiluted solution was placed SC prior to incisional closure. Dogs were scored at 0.5, 1, 2, 3, 6, 8 and 18 hours post-extubation by one observer. Dogs were evaluated using a visual analogue scale (VAS) for pain and sedation, and a composite pain scale (CPS) that included physiologic and behavioral variables. Dogs were treated with 0.22 mg kg−1 butorphanol + acepromazine if their VAS (pain) score was >50. Parametric variables were analyzed using Student's t-test or repeated measures anova as appropriate. Non-parametric variables were analyzed by χ2-test.
Results There were no significant differences in age, weight, incision length, surgery time, anesthesia time, or total thiopental dose among groups. Peak post-surgical pain scores for all groups occurred at 0.5 hours and returned to baseline by 18 hours. Dogs in the BUP group had significantly lower VAS-pain scores overall than dogs in the SAL group. Seven out of 10 dogs in the SAL group, 4/10 in the LID group and 2/10 in the BUP group were treated with supplemental acepromazine and butorphanol. No differences between groups were detected with the CPS. No adverse side-effects were observed.
Conclusions and clinical relevance Our findings support the use of IP and SC bupivacaine for post-operative analgesia following OHE in the dog.