title: Clinical evaluation of total intravenous anesthesia using a combination of propofol and medetomidine following anesthesia induction with medetomidine, guaifenesin and propofol for castration in Thoroughbred horses.
abstract: Seven Thoroughbred horses were castrated under total intravenous anesthesia (TIVA) using propofol and medetomidine. After premedication with medetomidine (5.0 µg/kg, intravenously), anesthesia was induced with guaifenesin (100 mg/kg, intravenously) and propofol (3.0 mg/kg, intravenously) and maintained with constant rate infusions of medetomidine (0.05 µg/kg/min) and propofol (0.1 mg/kg/min). Quality of induction was judged excellent to good. Three horses showed insufficient anesthesia and received additional anesthetic. Arterial blood pressure changed within an acceptable range in all horses. Decreases in respiratory rate and hypercapnia were observed in all horses. Three horses showed apnea within a short period of time. Recovery from anesthesia was calm and smooth in all horses. The TIVA-regimen used in this study provides clinically effective anesthesia for castration in horses. However, assisted ventilation should be considered to minimize respiratory depression.
authors.affiliation: Racehorse Clinic, Miho Training Center, Japan Racing Association, Inashiki-gun, Ibaraki 300–0439, Japan. KAZUOMI_OKU@jra.go.jp
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Oku
authors.forename: Masashi
authors.initials: M
authors.lastname: Kakizaki
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ono
authors.forename: Minoru
authors.initials: M
authors.lastname: Ohta
mesh_terms: D000768:Anesthesia, General / Q000662:veterinary; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001049:Apnea / Q000139:chemically induced / Q000662:veterinary; D001794:Blood Pressure / Q000187:drug effects; D005100:Expectorants / Q000008:administration & dosage / Q000494:pharmacology; D006140:Guaifenesin / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006736:Horses; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D009919:Orchiectomy / Q000662:veterinary*; D015742:Propofol / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*
chemical_list: D018686:Anesthetics, Intravenous; D005100:Expectorants; D006993:Hypnotics and Sedatives; D006140:Guaifenesin; D020926:Medetomidine; D015742:Propofol