Dissociative Anaesthesia During Field and Hospital Conditions for Castration of Colts
ABSTRACT The principal aim of this study was to evaluate dissociative anaesthesia for castration of colts during field conditions. Three dissociative anaesthetic protocols were evaluated during castration of colts in an animal hospital. The protocol considered to be the most suitable was thereafter evaluated during castration of colts under field conditions. Respiratory and haemodynamic parameters and the response to surgery were determined during anaesthesia. All horses breathed air spontaneously during anaesthesia. Under hospital conditions 26 colts were randomised to receive one of three anaesthetic protocols: Romifidine and tiletamine-zolazepam (RZ); acepromazine, romifidine and tiletamine-zolazepam (ARZ); or acepromazine, romifidine, butorphanol and tiletamine-zolazepam (ARBZ). The surgeon was blinded to the anaesthetic protocol used and decided whether supplemental anaesthesia was needed to complete surgery. Under field conditions 31 colts were castrated during anaesthesia with the ARBZ protocol. All inductions, anaesthesia and recoveries were calm and without excitation under both hospital and field conditions. Surgery was performed within 5-20 minutes after the horses had assumed lateral recumbency during both hospital and field castrations. Under hospital conditions some horses needed supplemental anaesthesia with all three anaesthetic protocols to complete surgery. Interestingly, none of the horses castrated with protocol ARBZ under field conditions needed additional anaesthesia. Cardiorespiratory changes were within acceptable limits in these clinically healthy colts.
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ABSTRACT: The objective of this study was to determine the sedation, analgesia, and clinical reactions induced by an intravenous combination of romifidine and butorphanol in horses. The study was conducted on six saddle horses weighing 382 to 513 kg (mean ± SD; 449 ± 54 kg) and aged 6 to 14 years. The horses each underwent three treatments: intravenous romifidine 0.1 mg/kg body weight (RM; mean dose, 4.5 mL); intravenous butorphanol 0.05 mg/kg body weight (BT; mean dose, 2.4 mL); and intravenous romifidine 0.1 mg/kg body weight plus butorphanol 0.05 mg/kg body weight (RMBT; mean dose, 7.0 mL). The order of treatments was randomized. Heart rate, arterial pressure, respiratory rate, rectal temperature, sedation, and analgesia were measured at two times before treatments, 15 minutes apart (times –15 and 0) and at 5, 10, 15, 30, 45, 60, 75, 90, 120, 150, and 180 minutes after drug administration. The onset of sedation was approximately 5 minutes after intravenous injection of RM and RMBT, whereas BT did not present this effect. The duration of complete sedation was approximately 60 minutes for RMBT and approximately 35 minutes for RM. The RMBT treatment provided 30 minutes and the RM treatment 20 minutes of complete analgesia. Heart rate decreased significantly (P < .05) from basal values in the RM and RMBT treatments. Only RM caused significant decreases (P < .05) in the respiratory rate. Arterial pressure did not change significantly (P > .05) in any treatment. Intravenous administration of a romifidine−butorphanol combination to horses resulted in longer duration of sedation and analgesia than administration of romifidine or butorphanol alone. These effects probably resulted from a synergistic effect of the two drugs.Journal of Equine Veterinary Science 02/2009; 29(2):75-81. DOI:10.1016/j.jevs.2008.12.004 · 0.89 Impact Factor
Article: Field Anesthesia in the Equine[Show abstract] [Hide abstract]
ABSTRACT: Equine field practice commonly requires short- to medium-term anesthesia being induced in horses for either minor surgical or diagnostic procedures or for urgent medical care in emergency situations. Performing a general anesthetic in the field further increases the risk associated with equine anesthesia which already is high when compared with small animal or human anesthesia, even under best of hospital conditions. For this reason, cases for field anesthesia should be carefully selected and appropriate anesthesia protocols chosen by taking into account the peculiar setting of the location, the physical condition of the patient, and the specific circumstances of the surgical, diagnostic, or other procedures planned. This review provides an overview of the anesthetic techniques suitable for field anesthesia. First, the approach to the equine patient under field as compared with hospital conditions is addressed, followed by a detailed discussion of common field anesthetic protocols reported for use in adult horses and in foals. Finally, anesthetic protocols suitable for horses suffering injuries during or immediately after maximum exercise are addressed.Clinical Techniques in Equine Practice 06/2007; 6(2):111-119. DOI:10.1053/j.ctep.2007.05.003
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ABSTRACT: Objective To determine cardiovascular responses to administration of butorphanol in isoflurane-anesthetized horses.Study design Retrospective evaluation of anesthetic records.Animals Seventy-six horses anesthetized for a variety of clinical surgical procedures.Methods Anesthetic records of clinical equine patients anesthetized between January 1999 and December 2003 were searched. The records were reviewed for horses in which anesthesia was induced with ketamine and a benzodiazepine and maintained with isoflurane, and horses that received butorphanol intraoperatively. Exclusion criteria included horses in which the rate of infusion of an inotrope or end-tidal isoflurane concentration was changed 10 minutes before or after the butorphanol bolus. The horses were separated into two groups: group 1 horses received butorphanol at intervals as part of a balanced protocol, group 2 horses had ≥10% increase in heart rate (HR) or blood pressure within 10 minutes prior to butorphanol administration.Results Eighty-nine butorphanol administration events matched the criteria for inclusion, 49 in group 1 and 40 in group 2. There were no significant changes after butorphanol administration in systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), and heart rate (HR) in group 1, or in end-tidal carbon dioxide concentration or hemoglobin oxygen saturation in either group. There were significant decreases in SAP (p < 0.0001), MAP (p < 0.0005), and DAP (p < 0.0008) after butorphanol administration in group 2.Conclusions and clinical relevance The results presented here confirm that butorphanol can be administered to horses during isoflurane anesthesia without adverse effects on HR and arterial blood pressure. The results imply that butorphanol can deepen the plane of anesthesia and obtund sympathetic stimulation from a surgical procedure.Veterinary Anaesthesia and Analgesia 12/2007; 35(1):38 - 44. DOI:10.1111/j.1467-2995.2007.00355.x · 1.78 Impact Factor