Sacrococcygeal epidural administration of 0.5% bupivacaine in seven cats undergoing pelvic or hind limb orthopaedic procedures.

Background: Epidural administration of local anaesthetic agents provides good intraoperative antinociception for orthopaedic procedures of the pelvis and the pelvic limb. However, in cats the spinal cord extends approximately to the level of the first sacrococcygeal vertebra, and therefore the sacrococcygeal epidural could be a safer alternative to the lumbosacral epidural in cats. This case series describes perioperative analgesia and the haemodynamic status of seven client-owned cats that received sacrococcygeal epidural injection of 0.5% bupivacaine and underwent orthopaedic hind leg or pelvic surgeries under general anaesthesia.

Case presentation: Each cat received either 0.2 or 0.3 mL/kg of 0.5% bupivacaine with or without 0.2 mg/kg of morphine in the sacrococcygeal epidural space. Intraoperative antinociceptive response to surgical stimulus and haemodynamic changes were monitored and reported.

Conclusion: In these seven anaesthetised cats, 0.2 or 0.3 mL/kg of 0.5% bupivacaine, administered alone or in combination with morphine into the sacrococcygeal epidural space, enhanced antinociception so that intraoperative rescue analgesia was unnecessary in all but one cat. It also reduced the anticipated requirement for postoperative opioid use. However, a high incidence of hypotension was observed in the cats in this report, and hence intraoperative blood pressure monitoring should be considered mandatory in anaesthetised cats following epidural injection of local anaesthetic agents, regardless of injection site.