Intraoperative antinociception and postoperative analgesia following epidural anesthesia versus femoral and sciatic nerve blockade in dogs undergoing stifle joint surgery.

OBJECTIVE: To compare analgesic efficacy of preoperative epidural anesthesia with efficacy of femoral and sciatic nerve blockade in dogs undergoing hind limb orthopedic surgery. DESIGN: Prospective randomized blinded clinical study. ANIMALS: 22 dogs requiring stifle joint surgery. PROCEDURES: Dogs were premedicated with acepromazine and morphine, and anesthesia was induced with diazepam and propofol and maintained with sevoflurane in oxygen. Prior to surgery, a combination of 1.0% lidocaine solution with 0.25% bupivacaine solution was administered either into the lumbosacral epidural space (11 dogs) or perineurally along the femoral and sciatic nerves (11). Intraoperative nociception was assumed if heart rate or systolic blood pressure increased by > 10% from baseline, in which case fentanyl (2 µg/kg [0.9 µg/lb], IV) was administered as rescue analgesia. Following recovery from anesthesia, signs of postoperative pain were assessed every 30 minutes for 360 minutes from the time of local anesthetic administration via the modified Glasgow pain scale. Patients with scores > 5 (scale, 0 to 20) received hydromorphone (0.1 mg/kg [0.05 mg/lb], IV) as rescue analgesia and were then withdrawn from further pain scoring. RESULTS: Treatment groups did not differ significantly in the number fentanyl boluses administered for intraoperative rescue analgesia. Time to administration of first postoperative rescue analgesia was comparable between groups. Furthermore, there was no significant difference between groups in baseline pain scores, nor were there significant differences at any other point during the postoperative period. CONCLUSIONS AND CLINICAL RELEVANCE: Femoral and sciatic nerve blocks provided intraoperative antinociception and postoperative analgesia similar to epidural anesthesia in dogs undergoing stifle joint surgery.

Successful outcome of hepatectomy as treatment for liver lobe torsion in four domestic rabbits.

CASE DESCRIPTION: 4 rabbits (1.5 to 6 years old) were evaluated at the Angell Animal Medical Center from June 2007 to March 2009 because of nonspecific clinical signs including anorexia, lethargy, and decreased fecal output. CLINICAL FINDINGS: Physical examination revealed signs of pain in the cranial portion of the abdomen, gas distention of the gastrointestinal tract, and diminished borborygmi. Serum biochemical analyses and CBCs revealed moderately to markedly high alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities and mild to moderate anemia with polychromasia. Abdominal radiographic findings were nonspecific. Three of the 4 rabbits underwent abdominal ultrasonography; abnormalities in shape, size, echogenicity, and blood flow of the liver, indicative of liver lobe torsion, were detected. TREATMENT AND OUTCOME: All 4 rabbits underwent surgery, during which liver lobe torsion was confirmed and the affected liver lobe was resected. Histologic examination of sections of the excised lobe obtained from 3 of the 4 rabbits revealed severe, diffuse, acute to sub-acute hepatic ischemic necrosis. All rabbits recovered from surgery; owners reported that the rabbits were doing well 22 to 43 months after surgery. CLINICAL RELEVANCE: Liver lobe torsions in any species are rarely reported, yet 4 cases of liver lobe torsion in domestic rabbits were treated at 1 referral center in a 2-year period. In rabbits, clinical signs of this condition are nonspecific and results of additional tests, including abdominal ultrasonography and serum biochemical analysis, are necessary for diagnosis. Prompt diagnosis and hepatectomy of the affected lobe are recommended and appear to be associated with an excellent prognosis.

Ischemic postconditioning does not attenuate ischemia-reperfusion injury of rabbit small intestine.

OBJECTIVE: To determine whether ischemic postconditioning can attenuate intestinal ischemia-reperfusion (I-R) injury and has a beneficial effect on tissue blood flow during reperfusion. STUDY DESIGN: In vivo experimental study. ANIMALS: New Zealand White rabbits (n=6). METHODS: Rabbits were anesthetized with pentobarbital, to avoid the preconditioning effects of volatile anesthetics, and ventilated with room air. Rectal temperature, hemodynamics, and normocapnia were maintained. After celiotomy, 3 jejunal segments were isolated in each rabbit for the following groups: (1) control, (2) I-R, and (3) I-R with postconditioning. I-R was induced by a 45-minute occlusion of the segment jejunal artery followed by 2-hour reperfusion. The postconditioning segment had 4 cycles of 30-second reperfusion and 30-second reocclusion during the initial 4 minutes of reperfusion. Stable isotope-labeled microspheres were used to measure intestinal blood flow at baseline, end occlusion, and end reperfusion. At the end of reperfusion, intestine segments were harvested and the rabbits euthanatized. A semiquantitative histopathologic evaluation (0-5) was conducted by a single, blinded observer. Wet-to-dry weight ratios were calculated to assess intestinal edema. RESULTS: There was no significant difference in grade of necrosis, tissue wet-to-dry weight ratios, or blood flow at any time point between ischemic and postconditioning groups. CONCLUSIONS: Ischemic postconditioning was ineffective in this model of intestinal I-R. CLINICAL RELEVANCE: Further experimental studies will need to be performed before clinical application of postconditioning for intestinal ischemia.