title: Combination of continuous intravenous infusion using a mixture of guaifenesin-ketamine-medetomidine and sevoflurane anesthesia in horses.
abstract: The anesthetic and cardiovascular effects of a combination of continuous intravenous infusion using a mixture of 100 g/L guaifenesin-4 g/L ketamine-5 mg/L medetomidine (0.25 ml/kg/hr) and oxygen-sevoflurane (OS) anesthesia (GKM-OS anesthesia) in horses were evaluated. The right carotid artery of each of 12 horses was raised surgically into a subcutaneous position under GKM-OS anesthesia (n=6) or OS anesthesia (n=6). The end-tidal concentration of sevoflurane (EtSEV) required to maintain surgical anesthesia was around 1.5% in GKM-OS and 3.0% in OS anesthesia. Mean arterial blood pressure (MABP) was maintained at around 80 mmHg under GKM-OS anesthesia, while infusion of dobutamine (0.39+/-0.10 microg/kg/min) was necessary to maintain MABP at 60 mmHg under OS anesthesia. The horses were able to stand at 36+/-26 min after cessation of GKM-OS anesthesia and at 48+/-19 minutes after OS anesthesia. The cardiovascular effects were evaluated in 12 horses anesthetized with GKM-OS anesthesia using 1.5% of EtSEV (n=6) or OS anesthesia using 3.0% of EtSEV (n=6). During GKM-OS anesthesia, cardiac output and peripheral vascular resistance was maintained at about 70% of the baseline value before anesthesia, and MABP was maintained over 70 mmHg. During OS anesthesia, infusion of dobutamine (0.59+/-0.24 microg/kg/min) was necessary to maintain MABP at 70 mmHg. Infusion of dobutamine enabled to maintaine cardiac output at about 80% of the baseline value; however, it induced the development of severe tachycardia in a horse anesthetized with sevoflurane. GKM-OS anesthesia may be useful for prolonged equine surgery because of its minimal cardiovascular effect and good recovery.
authors.affiliation: Department of Veterinary Surgery I, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yamashita
authors.forename: M
authors.initials: M
authors.lastname: Satoh
authors.forename: A
authors.initials: A
authors.lastname: Umikawa
authors.forename: A
authors.initials: A
authors.lastname: Tsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Yajima
authors.forename: S
authors.initials: S
authors.lastname: Tsubakishita
authors.forename: T
authors.initials: T
authors.lastname: Seno
authors.forename: S
authors.initials: S
authors.lastname: Katoh
authors.forename: Y
authors.initials: Y
authors.lastname: Izumisawa
authors.forename: T
authors.initials: T
authors.lastname: Kotani
mesh_terms: D000758:Anesthesia / Q000662:veterinary*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D004359:Drug Therapy, Combination; D006140:Guaifenesin / Q000008:administration & dosage; D006339:Heart Rate / Q000187:drug effects; D006736:Horses; D007262:Infusions, Intravenous / Q000662:veterinary; D007649:Ketamine / Q000008:administration & dosage; D020926:Medetomidine / Q000008:administration & dosage; D008738:Methyl Ethers / Q000008:administration & dosage; D012119:Respiration / Q000187:drug effects; D000077149:Sevoflurane
chemical_list: D008738:Methyl Ethers; D000077149:Sevoflurane; D006140:Guaifenesin; D007649:Ketamine; D020926:Medetomidine