title: Effects of general anesthesia on myoelectric activity of the intestine in horses.
abstract: Myoelectric activity was monitored from the terminal ileum, cecum, and colonic pelvic flexure by use of AgpAgCl bipolar electrodes in 4 adult horses before, during, and after general anesthesia. Horses were anesthetized by way of 3 commonly used regimens, including xylazine (1.1 mg/kg of body weight) and ketamine hydrochloride (2.2 mg/kg); thiopental sodium (7.7 mg/kg), followed by halothane vaporized in oxygen; and thiopental sodium (2.5 g) in guaifenesin (100 mg/ml) solution given to effect, followed by halothane in oxygen. All 3 anesthetic regimens decreased intestinal spike-burst activity in the areas monitored. The slowest return to preanesthetic myoelectric activity was observed after xylazine and ketamine administration. After both of the barbiturate/halothane anesthetic regimens, there was a rebound increase in spike-burst frequency, without alteration in the proportion of propagative myoelectric events. All 3 anesthetic regimens appeared to reset the timing of the small and large intestinal migrating myoelectric complexes. By 9 hours after recovery from anesthesia, the effects of anesthesia, irrespective of regimen, had disappeared. Although anesthesia significantly (P less than 0.05) altered intestinal myoelectric activity, no particular anesthetic regimen had a prolonged effect. Results of our study indicate that the particular chosen regimen of general anesthesia is unimportant in development of motility disturbances in horses after anesthesia.
authors.affiliation: Department of Applied Veterinary Medicine, School of Veterinary Studies, Murdoch University, Western Australia.
authors.forename: G D
authors.initials: GD
authors.lastname: Lester
authors.forename: J R
authors.initials: JR
authors.lastname: Bolton
authors.forename: L K
authors.initials: LK
authors.lastname: Cullen
authors.forename: S M
authors.initials: SM
authors.lastname: Thurgate
mesh_terms: D000075:Acepromazine; D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D002432:Cecum / Q000502:physiology; D003106:Colon / Q000502:physiology; D004567:Electrodes, Implanted; D004576:Electromyography / Q000662:veterinary; D001330:Electronic Data Processing; D006140:Guaifenesin; D006221:Halothane; D006736:Horses / Q000502:physiology*; D007082:Ileum / Q000502:physiology; D007422:Intestines / Q000502:physiology*; D007649:Ketamine; D011897:Random Allocation; D013874:Thiopental; D014991:Xylazine
chemical_list: D014991:Xylazine; D006140:Guaifenesin; D000075:Acepromazine; D007649:Ketamine; D013874:Thiopental; D006221:Halothane