RESUMEN
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.
Asunto(s)
Anestesia General/veterinaria , Caballos/fisiología , Intestinos/fisiología , Acepromazina , Animales , Ciego/fisiología , Colon/fisiología , Electrodos Implantados , Electromiografía/veterinaria , Procesamiento Automatizado de Datos , Guaifenesina , Halotano , Íleon/fisiología , Ketamina , Distribución Aleatoria , Tiopental , XilazinaRESUMEN
Extracellular myoelectric activity from the terminal ileum, cecum, and colonic pelvic flexure was assessed in 4 adult horses. The collection and analysis of myoelectric data involved the development and use of a computer-based system. After collection, the myoelectric signal was digitally filtered to enhance the activity of interest. The smoothed signal was then processed by use of computer programs designed to identify and count spike-burst activity and estimate burst duration. The intense phases of myoelectric complexes also were identified. The propagation of myoelectric spike-burst activity was assessed over 3 electrode sites to identify the propagative patterns of intestinal motility. There was high correlation between the results of computer-based analysis and those of visual analysis. We concluded that the computer provides a fast, accurate, and reliable means of assessing myoelectric activity.
Asunto(s)
Caballos/fisiología , Intestinos/fisiología , Animales , Ciego/fisiología , Colon/fisiología , Electrodos Implantados/veterinaria , Electromiografía/veterinaria , Procesamiento Automatizado de Datos , Íleon/fisiologíaRESUMEN
A technique for measuring changes in the dimensions of elastomeric impression materials is described. The technique involves using holographic interferometry to determine the rate of dimensional change on setting of the materials. The total change in dimension is found by integration with time. The sensitivity of the technique allows accurate determination of these quantities. Holography involves no direct physical contact with the test sample and more than one sample can be tested at the same time under the same conditions. In a preliminary investigation, the technique was applied to several classes of commercially available impression materials. The results are compared with those obtained by other techniques.