A comparison of subarachnoid buprenorphine or xylazine as an adjunct to lidocaine for analgesia in goats.

Objective: To test the hypothesis that subarachnoid administration of buprenorphine and lidocaine provides more intense and longer lasting perioperative analgesia with less side effects than xylazine and lidocaine in goats.
Study Design: Randomized, blinded, controlled study. STUDY ANIMALS: Ten healthy female goats randomly assigned to two groups of five animals each.
Methods: After sedation with acepromazine (0.1 mg kg(-1)) intravenously (i.v.), lidocaine 2% (0.1 mL kg(-1)) combined with either xylazine (0.05 mg kg(-1); Group X) or buprenorphine (0.005 mg kg(-1); Group B) were injected intrathecally at the lumbo-sacral junction prior to stifle surgery. Electrocardiogram, heart rate, direct systolic, mean, and diastolic arterial blood pressures, rectal temperature and arterial blood gases were recorded as were post-operative sedation and pain scores using a visual analogue and numeric rating scale, respectively. Data were analyzed with one-way ANOVA for repeated measures, one-way anova, Friedman's and Kruskal-Wallis tests as necessary (p < 0.05).
Results: Surgery was successfully performed under both analgesia protocols. Total pain and sedation scores were significantly lower in the B as compared with X group from 3-24 hours and 30-120 minutes, respectively after subarachnoid drug administration (SDA). Heart rate and arterial blood pressures decreased post SDA and were consistently lower in X versus B (p < 0.05). In B arterial blood gas parameters did not change post SDA, but in group X PaCO(2) increased slightly within 15 minutes of SDA and remained elevated for at least 3 hours (p < 0.05).
Conclusion: In these goats intrathecal administration of buprenorphine and lidocaine produced more profound and longer lasting analgesia with less sedation and hemodynamic and respiratory impairment than xylazine with lidocaine.
Clinical Relevance: In these goats undergoing hind limb surgery, subarachnoid buprenorphine/lidocaine offered more intense and longer lasting analgesia than a xylazine/lidocaine combination, with less sedation and impairment of cardiopulmonary function.