Effects of epidural bupivacaine, bupivacaine-butorphanol and bupivacaine-morphine on postoperative analgesia for hind limb and pelvic orthopedic operations in dogs

The aim of this study was to compare the postoperative analgesic effects of epidural bupivacaine, bupivacaine-butorphanol and bupivacaine-morphine in hind limb and pelvic orthopedic operations in dogs. Three groups each containing 10 dogs were formed. Through the lumbosacral space, group B was administered bupivacaine, 1 mg kg-1; group BB was administered bupivacaine, 1 mg kg-1 and butorphanol, 0.25 mg kg-1; and group BM was administered bupivacaine, 1 mg kg-1 and morphine, 0.1 mg kg-1. Anaesthesia was induced with diazepam (0.2 mg kg-1) and propofol (5 mg kg-1) and maintenance with isoflurane in oxygen. Pain assessment was performed with the University of Melbourne Pain Scale (UMPS) by a blinded observer. Plasma cortisol levels were measured preoperatively and postoperatively. Postoperative pain scores were significantly lower at 2 hours in the group BM, and at 8 and 12 hours in the groups BB and BM compared to the group B (P=0.007). Group BM had a lower plasma cortisol level than the group B at 2 hours (P=0.002). Bupivacaine-butorphanol and bupivacaine-morphine use were shown to provide longer analgesia in the postoperative period; and the epidural administration of bupivacaine-butorphanol and bupivacaine-morphine was considered to be potentially useful in clinical practice.