Evaluation of intraperitoneal and incisional lidocaine or bupivacaine for analgesia following ovariohysterectomy in the dog

Abstract

Objective: To determine if intraperitoneal (i.p.) and incisional (s.c.) 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 i.p. (LID); 10 received 4.4 mg kg(-1) 0.75% bupivacaine i.p. (BUP); and 10 received 0.9% saline i.p. (SAL) upon completion of OHE. All i.p. doses were standardized to 0.88 mL kg(-1) with saline. An additional 2 mL of undiluted solution was placed s.c. 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 chi2-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 i.p. and s.c. bupivacaine for post-operative analgesia following OHE in the dog.