Role of preemptive epidural analgesia with lignocaine and pethidine in the management of postoperative inflammation and pain dogs

Twelve adult mongrel dogs of either sex weighing 13 to 22 kg were divided randomly in three equal groups. Atropine sulphate @ 0.65mg/animal and triflupromazine @ lmg/kg were given in animals of all the groups for premedication. After a gap of 10 min. normal saline (2 ml), lignocaine hydrochloride (2%) @ 4 mg/kg and pethidine hydrochloride (5%) @ 2 mg/kg were given epidurally at lumbosacral space in animals of groups I, II and III, respectively. Anaesthesia was then induced and maintained by repeated administration of thiopental sodium. A transverse fracture of tibia created at proximal metaphysis was repaired with cross pinning and interfragmentary wiring. Postoperatively all the animals were given streptopencillin @10 mg/kg b.i.d. for 5 days and diclofenac sodium @1 mg/kg i.m. for 3 days. To assess the efficacy of epidural drugs, postoperative wound hyperalgesia and movement associated pain and swelling were recorded in all the animals. Minimum wound hyperalgesia was recorded in animals of group III. It was always significantly (P<0.05) lesser than the group I up to day 7. In animals of group II also wound hyperalgesia was lesser as compared to group I but was higher than that of group III. Swelling increased up to a maximum of30.16% in group I, 28.5% in group II and only 19.56% in group III. Movement associated pain scores showed early weight bearing on affected limb in animals of group III as compared to that of group I and II. The results of this study suggested that epidural pethidine, if given preoperatively can preempt the postoperative hyperalgesia, swelling and pain in dogs operated for hind limb surgery. Lignocaine hydrochloride is also beneficial but its effects are not as potent as that produced by pethidine hydrochloride.