Abstract
Objective
To evaluate effects of anesthesia induced with alfaxalone and maintained with alfaxalone,
dexmedetomidine and remifentanil infusions in foals.
Study design
Prospective, experimental study.
Animals
A group of six healthy foals [median (range) 11 (8–33) days] undergoing abdominal
surgery.
Methods
Intravenous (IV) dexmedetomidine (3–7 μg kg−1) provided sedation for insertion of a pulmonary artery catheter. IV anesthesia was
induced with alfaxalone (2 mg kg−1) and maintained with alfaxalone (6 mg kg−1 hour−1), dexmedetomidine (1 μg kg−1 hour−1) and remifentanil (3 μg kg−1 hour−1). Foals were endotracheally intubated and lungs were mechanically ventilated with
oxygen. Cardiac output (thermodilution), heart rate and systemic arterial pressure
were measured. Arterial and mixed venous blood was analyzed for PO2 and PCO2, and glucose, lactate and electrolyte concentrations. Anesthetic depth was subjectively
assessed. Systemic vascular resistance (SVR), oxygen utilization and intrapulmonary
shunt were calculated. Preinduction (PB) or 10 minutes postinduction (+10B) data were
used as baselines with one-way analysis of variance for repeated measures. Data are
mean ± standard deviation; significance was p ≤ 0.05.
Results
Duration of anesthesia was 129 ± 22 minutes. One foal was administered additional alfaxalone (0.5 mg kg−1) following induction. Cardiac index decreased to 107 ± 31 and 87 ± 21 mL kg−1 minute−1 at 60 and 80 minutes, respectively, compared with PB (157 ± 33 mL kg−1 minute−1). SVR increased to 1223 ± 166 dynes second−1 cm−5 at 80 minutes compared with +10B (704 ± 247 dynes second−1 cm−5). Mean arterial pressures were 63–128 mmHg. Time from stopping infusions to standing was 46–106 minutes. All foals were hypothermic (<36 °C) and three foals were administered atipamezole (0.05 mg kg−1) intramuscularly during recovery.
Conclusion
and clinical relevance Combined alfaxalone–dexmedetomidine–remifentanil provided suitable anesthesia to
permit laparotomy in foals. At the doses evaluated, prolonged recovery may occur.
Keywords
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References
- Evaluation of total intravenous anesthesia with propofol-guaifenesin-medetomidine and alfaxalone-guaifenesin-medetomidine in thoroughbred horses undergoing castration.J Vet Med Sci. 2017; 79: 2011-2018
- Review of hypoxaemia in anaesthetized horses: predisposing factors, consequences and management.Vet Anaesth Analg. 2017; 44: 397-408
- Drug disposition in the neonatal animal, with particular reference to the foal.Equine Vet J. 1984; 16: 364-367
- Prolonged anesthesia using sevoflurane, remifentanil and dexmedetomidine in a horse.Vet Anaesth Analg. 2013; 40: 521-526
- Blood concentrations of remifentanil during and after infusion in horses anesthetized with isoflurane and dexmedetomidine.Res Vet Sci. 2016; 107: 202-206
- Cardiopulmonary effects of an infusion of remifentanil or morphine in horses anesthetized with isoflurane and dexmedetomidine.Vet Anaesth Analg. 2014; 41: 346-356
- Comparison of lithium dilution and thermodilution cardiac output measurements in anaesthetised neonatal foals.Equine Vet J. 2002; 34: 598-601
- Alfaxalone for maintenance of anesthesia in ponies undergoing field castration: continuous infusion compared with intravenous boluses.Vet Anaesth Analg. 2017; 44: 832-840
- Anesthesia of the equine neonate in health and disease.Vet Clin North Am Equine Pract. 2015; 31: 567-585
- Alfaxalone and medetomidine intravenous infusion to maintain anaesthesia in colts undergoing field castration.Equine Vet J. 2013; 45: 315-319
- The pharmacokinetics and pharmacodynamics of the injectable anaesthetic alfaxalone in the horse.Vet Anaesth Analg. 2011; 38: 431-438
- Plasma pharmacokinetics and pharmacodynamics of alfaxalone in neonatal foals after an intravenous bolus of alfaxalone following premedication with butorphanol tartrate.Vet Anaesth Analg. 2012; 39: 503-510
- Alfaxalone for total intravenous anesthesia in horses.Vet Anaesth Analg. 2019; 46: 188-199
- Comparison of the influence of two different constant-rate infusions (dexmedetomidine versus morphine) on anesthetic requirements, cardiopulmonary function and recovery quality in isoflurane anesthetized horses.Res Vet Sci. 2013; 95: 1186-1194
- Blood glucose concentrations in critically ill neonatal foals.J Vet Intern Med. 2008; 22: 1223-1227
- Cardiopulmonary effects of diazepam-ketamine-isoflurane or xylazine-ketamine-isoflurane during abdominal surgery in foals.Am J Vet Res. 2009; 70: 574-580
- The effect of dexmedetomidine on nutrient organ blood flow.Anesth Analg. 1996; 83: 1160-1165
- Remifentanil in the horse: identification and detection of its major urinary metabolite.J Anal Toxicol. 2000; 24: 309-315
- Alfaxalone induction dose following administration of medetomidine and butorphanol in the dog.Vet Anaesth Analg. 2010; 37: 7-13
- Cardiopulmonary effects of two constant rate infusions of dexmedetomidine in isoflurane anaesthetized ponies.Vet Anaesth Analg. 2010; 37: 311-321
- Comparison of quality of recovery from anaesthesia in cats induced with propofol or alfaxalone.Vet Anaesth Analg. 2012; 39: 282-290
- Sedative and cardiopulmonary effects of dexmedetomidine infusions randomly receiving, or not, butorphanol in standing horses.Vet Rec. 2017; 181: 402
- Cardiorespiratory and anesthetic effects of combined alfaxalone, butorphanol, and medetomidine in Thoroughbred horses.J Equine Sci. 2016; 27: 7-11
- Pharmacology of sedative-analgesic agents: dexmedetomidine, remifentanil, ketamine, volatile anesthetics, and the role of peripheral mu antagonists.Crit Care Clin. 2009; 25: 451-469
- Cardiopulmonary effects and induction and recovery characteristics of isoflurane and sevoflurane in foals.J Am Vet Med Assoc. 2002; 221: 393-398
- Sedation and general anaesthesia of the foal.Equine Vet Educ. 2005; 15: 94-101
- An algorithm to describe the oxygen equilibrium curve for the Thoroughbred racehorse.Equine Vet J. 1994; 26: 500-502
- Systemic and pulmonary haemodynamics in normal neonatal foals.J Reprod Fertil Suppl. 1987; 35: 623-628
- Evaluation of five common induction protocols by comparison of hemodynamic responses to surgical manipulation in halothane-anesthetized horses.J Am Vet Med Assoc. 1996; 208: 252-257
- Hemodynamic function during neurectomy in halothane-anesthetized horses with or without constant dose detomidine infusion.Vet Surg. 1992; 21: 248-255
Article info
Publication history
Published online: January 21, 2019
Accepted:
January 9,
2019
Received in revised form:
January 9,
2019
Received:
July 5,
2018
Identification
Copyright
© 2019 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
