Postoperative pain management in dogs: Efficacy of pre-emptive analgesia with lignocaine and ketamine

The study was designed to evaluate the efficacy of epidural lignocaine and ketamine for post-operative pain management in experimental tibial fracture repair in 12 adult dogs divided in 3 equal groups. After atropine sulphate and triflupromazine groups premedication, normal saline (2 ml), lignocaine hydrochloride (2%) @ 4 mg/kg and ketamine hydrochloride (5%) @ 3 mg/kg wer e given epidurally at lumbosacral space in animals of groups 1, 2 and 3, re spectively, to assess their efficacy in pain management. Anaesthesia was in duced and maintained with thiopental sodium in all the groups. Left rib ia fracture created at proximal metaphysis was repaired with double pinning an d interfragmentory wiring, Wound hyperalgesia and swelling in animals of group I (normal saline) were significantly (P<0.05) higher than the group 3 (epidural ketamine). In grou p 2, wound hyperalgesia and swelling were lesser as compared to group 1 but higher than group 3. Movement associated pain scores showed early weight b earing on affected limb in animals of group 3 as compared to groups 1 and 2 . The results of this study suggest that epidural ketamine, if given preope ratively can pre-empt the post-operative hyperalgesia, swelling and pain. L ignocaine had only little beneficial effects.