Effects of lumbosacral epidural ketamine and lidocaine in xylazine-sedated cats

Abstract

In order to determine the analgesic and cardiovascular effects of the combination of epidural ketamine and lidocaine, 6 sedated cats were studied. Six healthy, young cats were used in a prospective randomised study. Each cat underwent 3 treatments, at least 1 week apart, via epidural injection: (1) ketamine (2.5 mg/kg), (2) lidocaine (4.0 mg/kg), and (3) ketamine (2.5 mg/kg) plus lidocaine (4.0 mg/kg). Epidural injections were administered through the lumbosacral space. Analgesia, motor block, sedation, heart rate, arterial blood pressure, respiratory rate and arterial oxygen saturation were measured. Rectal temperature was compared before and after sedation as well as after epidural administration of the drugs. Epidural administration of the ketamine/lidocaine combination induced prolonged analgesia extending from the coccygeal to the T13-L1 dermatomes, leading to severe ataxia. Cardiovascular effects were significant in all treatments: heart rate decreased, but there was a minimal reduction in arterial pressure. It was concluded that adding a dose of ketamine to epidural lidocaine in cats is feasible and effective.