EPIDURAL ADMINISTRATION OF BUPIVACAINE, MORPHINE, OR THEIR COMBINATION FOR POSTOPERATIVE ANALGESIA IN DOGS

Objective-To compare the analgesic effects of epidural administration of morphine (MOR), bupivacaine hydrochloride (BUP), their combination (COM), and 0.9% sterile NaCl solution (SAL) in dogs undergoing hind li mb orthopedic surgeries.Design-Blinded, randomized clinical trial. Ani mals-41 healthy dogs admitted for elective orthopedic surgeries involv ing the pelvis or hind limbs. Procedure-Analgesic and control agents w ere administered postoperatively prior to recovery from isoflurane ane sthesia. Ten dogs received MOR, 0.1 mg/kg of body weight; 10 received BUP, 0.5%, 1 ml/10-cm distance from the occipital protuberance to the lumbosacral space; 11 received COM; and 10 received SAL epidurally. Do gs were monitored for 24 hours after epidural injection for pain score , heart and respiratory rates, blood pressure, time to required admini stration of supplemental analgesic agent, total number of supplemental doses of analgesic agent required, and plasma concentrations of corti sol, MOR, and BUP. Results-Pain scores were significantly lower in dog s in the COM and BUP groups than in dogs in the SAL group. Pain scores also were significantly lower in dogs in the COM group than in dogs i n the MOR group. Time to required administration of supplemental analg esic agent was longer for dogs in the COM group than for dogs in the M OR and SAL groups. Total number of supplemental doses of analgesic age nt required was lower for dogs in the BUP and COM groups than for dogs in the SAL group. Clinical Implications-Postoperative epidural admini stration of COM or BUP alone provides longer-lasting analgesia, compar ed with MOR or SAL.