Articles: general-anesthesia.
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Acta Anaesthesiol Scand · Nov 1991
Comparative StudyA comparison of median frequency, spectral edge frequency, a frequency band power ratio, total power, and dominance shift in the determination of depth of anesthesia.
Five numerical descriptors were derived from the electroencephalogram (EEG), recorded, and processed (Tracor Nomad) during emergence from isoflurane-nitrous oxide anesthesia. The five descriptors (median frequency, spectral edge frequency-90%, total power, a frequency band power ratio, and the ratio of frontal to occipital power) were compared for their ability to predict imminent arousal. Arousal was defined as spontaneous movement, coughing or eye opening. ⋯ For median frequency, spectral edge frequency-90%, total power, and the frequency band power ratio, thresholds that predicted imminent arousal with sensitivities of 90% and specificities of 82-90% could be identified. The data indicate that, even in the favorable circumstances of the present study (uniform anesthetic technique, post hoC identification of thresholds), none of several previously popularized EEG descriptors (median frequency, spectral edge frequency-90%, total power, a frequency band power ratio) can serve as a completely reliable sole predictor of imminent arousal. As presently derived, these EEG descriptors at best provide trend information to be used in concert with other clinical signs of depth of anesthesia.
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Ann Ostet Ginecol Med Perinat · Nov 1991
[Incidence and complications of the aspiration of gastric contents syndrome during cesarean section in general anesthesia].
Maternal mortality attributed to anaesthesia, decreased in the last twenty years, has in inhalation of gastric contents one of its principal causes. Pregnant women are considered "high risk". In this retrospective investigation we studied 12,380 patients undergoing caesarean section in general anaesthesia between January 1977 and December 1991. ⋯ The emergency procedure (8 cases) and a difficult tracheal intubation (4 cases) are the more important risk factors. In our clinical practice we used prevention in few cases (3.1%). Our results suggest the utility in obstetric anaesthesia of high doses of thiopental (5-6 mg/kg); these doses didn't change the principal neonatal parameters, while give in pregnant woman a light anaesthesia.
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The possibility of processing sensory information during general anesthesia and the ability to recall it postoperatively is of major ethical, medical and even theoretical importance. Auditory stimuli especially are perceived intraoperatively and remembered postoperatively. Neuropsychological experiments indicate that sensory information can be processed and recalled both at a conscious and at an unconscious level. ⋯ Therefore, future studies should focus on several different points. The anesthetic state should be defined exactly and the functional state of the auditory modality should be monitored when auditory information is presented to the patients. The recollection of intraoperative events should be investigated using implicit memory tests, because these are regarded as more sensitive than explicit memory tests.
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Hysteria as a cause of failure to recover consciousness following general anaesthesia is a rare event. This case report describes such an instance in a young, healthy 22-year-old female suffering severe dental phobia who was undergoing dental conservation. The literature is reviewed and a summary of the possible physiological mechanisms involved is given.