Bupivacaine: Morphological effects on spinal cords of cats and durations of spinal anesthesia in sheep

Summary Bupivacaine HCl, 0.25, 0.5 and 1.0%, was administered epidurally to cats and the duration of block recorded. Subsequent gross and microscopic examination of the spinal cords revealed morphological changes due to the presence of the polyethylene catheter in the epidural space. There was no evidence of drug-induced morphological changes. Spinal anesthesia with 0.25, 0.5 and 1.0% bupivacaine HCl was performed in sheep, and durations of sensory analgesia and motor block were recorded. Despite certain limitations, inherent in all animal models, the sheep is an excellent model for the study of spinal anesthetic agents.