Der Anaesthesist
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Experimental evidence from various neuropsychological and neurophysiological fields indicates that an oscillatory brain mechanism in a frequency range of 30-40 Hz is necessary for adequate sensory information processing. An oscillatory component of that particular frequency range can also be observed in the mid-latency auditory evoked potentials. Thus general anesthesia can be defined as a suppression of sensory information processing, and the effect of the i.v. anesthetics, Propofol and ketamine, on auditory perception and auditory-evoked potentials was therefore studied. ⋯ In contrast to Propofol, ketamine does not alter auditory perception. Suppression of sensory information processing must take place at a higher cortical level in a dissociative manner. The persistence of a 30-40 Hz oscillation must be seen in connection with dreams and hallucinations as reported for the drug and may be interpreted as insufficient suppression of sensory information processing under ketamine anesthesia.
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Since ketamine has been incriminated as triggering malignant hyperthermia (MH) [3, 9, 13, 14, 18], but has still been used uneventfully in MH susceptible patients, we performed an in vitro study to examine the safety of ketamine for use in human MH. METHODS. Muscle specimens of 20 patients who had muscle biopsies to diagnose MH were investigated. ⋯ Analogous findings in frog sartorius muscles can be found in the literature. Whereas the effect of ketamine on indirectly stimulated muscle has been investigated by several authors, the underlying mechanism of ketamine-induced twitch suppression in directly stimulated muscles is not known. Inhibition of calcium release from or accelerated uptake into the sarcoplasmatic reticulum have been reported.
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Gallstone lithotripsy is a new and noninvasive therapeutic option for approximately 20% of patients who harbor cholesterol gallstones. Technologically advanced second-generation lithotripters such as the Dornier MPL 9000 device have greatly simplified biliary lithotripsy with a consecutive reduction in anesthetic requirements. Despite these technical improvements, patients still can experience considerable pain and discomfort during biliary ESWL. ⋯ If not, more alfentanil was allowed to accumulate until continuous treatment was tolerated. Further in- or decreases of the infusion rate were titrated according to patient response. Registered variables included the required alfentanil loading dose, maintenance and total doses, and the applied shock wave energy approximated by multiplication of shock wave number and voltage squared.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
[Cannulation of the internal jugular vein using 2 ultrasonic technics. A comparative controlled study].
The internal jugular vein (IJV) is a common access route to the central venous system. Anatomical landmarks (group I) are normally used for localization of the IJV. We have compared this method with two other methods based on ultrasonic waves to identify the IJV and the carotid artery (CA) (even in atypical positions). ⋯ One patient (group I) displayed a hematoma following inadvertent puncture of the CA. In one patient in group II the IJV and CA could not be distinguished as one was overlying the other. The echocamera provided improved localization of the IJV and the CA in comparison with the Doppler ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)