Physiological, haemodynamic and biochemical changes during epidural bupivacaine alone or with buprenorphine for ovariohysterectomy in dogs

The study was conducted to evaluate physiological, haemodynamic and biochemical changes after epidural injection of bupivacaine alone or with buprenorphine for ovariohysterectomy in 12 dogs. The animals were divided into two groups, I and II. Premedication was done with atropine sulphate 0.04 mg/kg b.wt, i.m. followed by diazepam 0.3 mg/kg b.wt, i.v. The general anaesthesia was induced and maintained with propofol i.v. at 4 mg/kg and 2 mg/kg b.wt, respectively. Bupivacaine (0.5 mg/kg b.wt) alone was administered epidurally at lumbosacral space in group I animals and bupivacaine (0.5 mg/kg b.wt) and buprenorphine (0.05 mg/kg b.wt) were administered in group II animals. The physiological, haemodynamic and biochemical parameters were recorded before sedation, after epidural analgesia, immediately after surgery, 2 h and 6 h after surgery. Rectal temperature reduced significantly in both groups. Respiratory rate was significantly lower in both groups immediately after epidural analgesia followed by a gradual increase up to 6 h. The mean heart and pulse rates significantly (P<0.01) decreased immediately after epidural analgesia. A significant (P<0.05) reduction in SpO₂ was noticed in group II. There was no electrocardiographic change in all the intervals in both groups. The serum glucose level reduced significantly (P<0.01) after epidural analgesia followed by an increase up to 6 h after surgery in both groups. A significant (P<0.01) reduction in serum urea nitrogen was observed after epidural analgesia up to 6 h in group I and 2 h in group II animals after surgery. Serum creatinine level did not show any variation in both groups.