Ketamine-xylazine-acepromazine anesthesia and postoperative recovery in rats

We evaluated the effect of ketamine-xylazine-acepromazine anesthesia (31.25, 6.25, and 1.25 mg/kg subcutaneously, respectively) on postsurgical recovery in male Sprague-Dawley (Crl:SD) rats undergoing laparotomy with and without the postoperative analgesic ketorolac. Recovery was determined by changes in body weight (BW) and water intake. The time of ketorolac administration (5 mg/kg intramuscularly), 60 min after anesthetic injection, was based on return of the pedal withdrawal reflex in Long-Evans (HsdBlu:LE) rats undergoing stereotaxic surgery in a separate experiment. Results were compared with those of housing and anesthesia controls as well as of laparotomized rats receiving a single sugared treat for nonpharmacologic management of postoperative pain. Surgery took place on day 0; the first 24 h postsurgery was considered the "acute phase," and days 1 through 4 comprised the "recovery phase." Results suggest that 1) the anesthetic mixture is fast- and long-acting and provides sufficient immobility, loss of consciousness, and analgesia; 2) during the acute phase, rats subjected to laparotomy did not lose more BW than rats exposed to anesthesia alone; 3) water intake during both phases did not significantly differ between treatment groups; 4) postsurgical ketorolac administration did not minimize BW loss during the acute phase nor cause any adverse effects under this anesthetic regimen; and 5) provision of single sugared treats had salutary effects on BW recovery. This finding suggests that postsurgical BW loss after use of this anesthetic mixture is due to distress unrelated to pain; this nonpain distress may have masked potential beneficial effects of ketorolac.