Effects of sub-anaesthetic (low) dose ketamine infusion on intra-operative and postoperative pain in goats anaesthetized with diazepam-ketamine prior to rumenotomy

The study evaluated the effect of sub-anaesthetic ketamine on peri- operative pain in goats anaesthesized with diazepam-ketamine prior to rumenotomy. Nine West African dwarf goats used for the study were divided into three (3) groups (n=3). Group 1 received diazepam (0.5mg/kg IV) and ketamine (5mg/kg IV), group 2 received diazepam (0.5mg/kg IV), ketamine (5mg/kg IV) and continuous IV infusion (CRI) ketamine (20µg/kg/min) 30 minutes prior to rumenotomy and group 3 received diazepam (0.5mg/kg IV), ketamine (5mg/kg IV) and CRI ketamine (20µg/kg/min) followed by rumenotomy immediately. The mean rank pain scores of CRI ketamine groups 2 and 3 were lower than that of group 1 (control) during incision of rumen and suturing of skin, muscle and rumen. There were no significant difference in mean rank pain scores during incision of skin (P=0.239), muscle (P=0.76), peritoneum (P=1.0) and rumen (P=0.083). Mean rank pain scores of the groups were not significantly different during suturing of skin (P= 0.064) and muscle (P=0.064) but significantly different during rumen suturing (P=0.004). Respiratory rate (RR) of group 1 was significantly (p<0.05) higher than RR of other groups at 40 and 60 minutes IOP as well as at 60 minutes POS. At 80 minutes post-surgery, there was no significant difference in the RR across the groups (P˃0.05). On exertion of pressure on the site of incision wounds, goats in group 1 showed pain with outcry, those in group 2 showed no sign of pain while in group 3 moderate signs of pain were exhibited by goats. It was concluded that the sub-anaesthetic dose of ketamine infused (20µg/kg/min) did not effectively ameliorate intra-operative rumenotomy-induced pain in diazepam-ketamine anaesthesized goats. However less postoperative pain and hyperalgesia were recorded in the groups infused with low dose ketamine compared to the control group.Keywords: Diazepam, Ketamine, Pain, Rumenotomy, Sub-anaesthetic