Objective: This study aimed to compare the effects of low-dose subarachnoid injections of 2% lidocaine (LIDO) and 0.5% bupivacaine (BUPI) in goats.
Animals: 6 healthy, privately owned female goats.
Methods: In this randomized blind crossover clinical trial, each goat received 0.05 mL/kg-1 of LIDO, BUPI, or sterile saline solution into the lumbosacral subarachnoid space, with a seven-day washout. Cardiorespiratory variables, rectal temperature, and somatosensory (pinprick) and motor (ataxia) functions were recorded at baseline (time 0) and 2, 5, 10, 15, and 30 minutes after injection, then every 20 minutes until the goat was standing and able to walk. Time to regain somatosensory and motor functions was compared between treatments using Kaplan-Meier survival curves and the Cox proportional hazards model. Linear mixed-effects models were used to compare cardiorespiratory variables between treatments and over time. A P value ≤ .05 was considered significant.
Results: Somatosensory recovery was longer with BUPI, though not statistically significant. The median time to stand was 50 (50, 67) minutes after LIDO injection and 104 (101, 156) minutes after BUPI injection (P = .031). The median time to walk was 72 (54, 85) minutes after LIDO versus 225 (220, 245) minutes after BUPI injection (P = .031). Cardiovascular and respiratory variables showed no significant differences between treatments.
Clinical relevance: Despite prolonged ataxia with BUPI, pinprick sensation recovery did not differ. At reduced doses, both LIDO and BUPI are deemed acceptable for short procedures of the flank, pelvic limb, or tail in healthy goats.
Keywords: bupivacaine; caprine; lidocaine; motor blockade; subarachnoid.