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 (IV), 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 PaCO2 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