Effects of a continuous rate infusion of butorphanol in isoflurane-anesthetized horses on cardiorespiratory parameters, recovery quality, gastrointestinal motility and serum cortisol concentrations

Abstract

Conception, design, intellectual and scientific content of the study; statistical analysis. ABSTRACT PURPOSE:To assess the cardiorespiratory parametes, recovery, gastrointestinal motility and serum cortisol concentrations in horses anesthetized with isoflurane with or without a continuous rate infusion (CRI) of butorphanol for orchiectomy. METHODS:Twelve adult, intact, male horses weighing 332 ± 55 kg were included in the study. Xilazine was administered as premedication. Anesthesia was induced with ketamine and midazolam and maintained with isoflurane. Butorphanol (0.025 mg kg -1 bolus) or an equivalent volume of saline (0.9%) was given intravenously followed by a CRI of butorphanol (BG) (13 µg kg -1 hour -1 ) or saline (CG). Cardiorespiratory variables were recorded before (T0) and every 15 minutes for 75 minutes after the start of infusion.Serum cortisol concentration was measured at T0 and 60 minutes, and 30 minutes and 19 hours after the horse stood up. Recovery from anesthesia was evaluated using a scoring system. Gastrointestinal motility was evaluated before anesthesia and during 24 hours after recovery. RESULTS:There were no significant differences between groups in cardiopulmonary variables, or recovery scores or serum cortisol concentrations. A reduction in gastrointestinal motility was recorded for 60 minutes in BG. CONCLUSIONS:Continuous rate infusion of butorphanol in horses anesthetized with isoflurane did not adversely affect the cardiopulmonary variables monitored, or recovery scores. A small but statistically significant reduction in gastrointestinal motility occurred in the butorphanol group.

Recovery of horses from general anaesthesia: A systematic review (2000–2020) of the influence of anaesthetic protocol on recovery quality

“…The addition of butorphanol, 111,112 alfaxalone, 148 propofol, 96 guaifenesin‐ketamine 121,122 or ketamine‐romifidine 120 to PIVA protocols did not improve QR in several studies.…”

Efeitos Hemodinâmicos Da Infusão Contínua De Butorfanol Em Cães Anestesiados Com Propofol

“…Em cães, a dose do butorfanol parece influenciar diretamente o cronotropismo cardíaco, visto que, em outro estudo, ao se utilizarem doses consideravelmente mais elevadas (0,1 e 0,2 mg/kg/min), constatou-se redução acentuada da variável, independente do uso prévio de atropina (4) . Já em equinos, taxas de infusão de 13 µg/kg/h (10) e 23,7 µg/kg/h (11) não foram capazes de induzir a bradicardia.…”

Recovery after General Anaesthesia in Adult Horses: A Structured Summary of the Literature

“…Whereas Chesnel and Clutton (2013) [240] reported uneventful recoveries after morphine CRIs (0.1-0.2 mg/kg/hr), experimental and clinical studies from another research group showed recoveries with excitement [242,245]. A butorphanol CRI did not influence recoveries, but the advantages of its use are limited [229,231,244]. A fentanyl CRI produced highly undesirable, potentially injurious excitatory behaviour [226].…”