Effects of Continuous Rate Intravenous Infusion of Butorphanol on Physiologic and Outcome Variables in Horses after Celiotomy

Abstract

A randomized, controlled, blinded clinical trial was performed to determine whether butorphanol administered by continuous rate infusion (CRI) for 24 hours after abdominal surgery would decrease pain and surgical stress responses and improve recovery in horses. Thirty-one horses undergoing exploratory celiotomy for abdominal pain were randomly assigned to receive butorphanol CRI (13 g/kg/h for 24 hours after surgery; treatment) or isotonic saline (control). All horses received flunixin meglumine (1.1 mg/kg IV q12h). There were no significant differences between treatment and control horses in preoperative or operative variables. Treatment horses had significantly lower plasma cortisol concentration compared with control horses at 2, 8, 12, 24, 36, and 48 hours after surgery. Mean weight loss while hospitalized was significantly less for treatment horses than control horses, whether expressed as total decrease in body weight (13.9 Ϯ 3.4 and 27.9 Ϯ 4.5 kg, respectively) or as a percentage decrease in body weight (2.6 Ϯ 0.7 and 6.3 Ϯ 1.1%, respectively). Treatment horses were significantly delayed in time to first passage of feces (median times of 15 and 4 hours, respectively). Treatment horses had significantly improved behavior scores during the first 24 hours after surgery, consistent with the conclusion that they experienced less pain during that time. Butorphanol CRI during the immediate postoperative period significantly decreased plasma cortisol concentrations and improved recovery characteristics in horses undergoing abdominal surgery.Key words: Behavior; Colic; Cortisol; Pain management; Stress.I n recent years, there has been a growing interest in recognition and management of pain and surgical stress responses in veterinary medicine. [1][2][3][4][5][6] However, investigation of analgesia in horses has been largely limited to pharmacokinetic studies of drugs or the effects of these drugs in experimental models of induced pain. 5,7-14 Evaluations of analgesic efficacy in equine clinical patients are minimal and primarily focus on responses to nonsteroidal anti-inflammatory agents in horses with orthopedic pain or retrospective studies of responses of horses with colic to various analgesic medications. 5,12,[14][15][16][17] These studies have been complicated by difficulties in accurately assessing and quantifying pain in a nonverbal species. [2][3][4][5][6]16,[18][19][20] Horses undergoing exploratory celiotomy for acute abdominal pain usually receive flunixin meglumine, a nonsteroidal anti-inflammatory drug (NSAID), although doses and dose intervals have varied. In human beings, NSAID medications are considered insufficient for management of pain related to abdominal surgery and a combination of opiates Pullman, WA 99164; e-mail: dsellon@vetmed.wsu.edu. Submitted August 11, 2003; Revised December 9, 2003; Accepted January 16, 2004. Copyright and nonsteroidal analgesic agents is preferred as a multimodal plan for pain management. [21][22][23] Horses that do not exhibit classic behavioral signs of abd...

Systemic and anti-nociceptive effects of prolonged lidocaine, ketamine, and butorphanol infusions alone and in combination in healthy horses

“…We also observed a decrease in fecal weight during the final 24 hours of the 96-hour infusion for horses treated with butorphanol alone, after all of the beads had been passed. This supports prior work in healthy horses [20] and horses post-celiotomy [14], which also showed decreased fecal output. But, in healthy horses, a short duration butorphanol CRI did not significantly alter duodenal motility [13].…”

“…The opioid drug butorphanol, a kappa (OP2) agonist and competitive mu (OP3) antagonist, is commonly administered in the horse with varying success. No anti-nociceptive properties were noted in clinically normal horses in response to visceral distension or noxious thermal stimulus [13] but pain scores were significantly decreased in horses administered butorphanol as a constant rate infusion in the immediate post-operative period following exploratory laparotomy [14]. …”

Expression of cyclooxygenase-1 and -2 in the left dorsal colon after different durations of ischemia and reperfusion in horses

“…28 After recovery, horses were placed in a stall, monitored and scored for signs of pain according to an established scoring system, 12,29 and administered butorphanol (0.05 mg/kg, IM, q 4 h) to provide analgesia. 30 These horses were anesthetized again to collect tissues at 18 hours of reperfusion. All horses were euthanatized during anesthesia after final tissue collection with an overdose of pentobarbital sodium (88 mg/kg, IV).…”

Practical Fluid Therapy and Treatment Modalities for Field Conditions for Horses and Foals with Gastrointestinal Problems

“…Butorphanol can be administered as intermittent bolus doses or as a continuous infusion. 22 Butorphanol is often given as an initial IV bolus dose (0.01-0.02 mg/kg) for procedures in the field combined with alpha-2 agonists. If continuous pain control is needed, an infusion (0.013 mg/kg/h) can be started and has several benefits over intermittent bolus dosing, including smoother pain control and decreased negative effects of the medication.…”

“…If continuous pain control is needed, an infusion (0.013 mg/kg/h) can be started and has several benefits over intermittent bolus dosing, including smoother pain control and decreased negative effects of the medication. 22 Intermittent bolus administration of butorphanol can be given IV or IM.…”