Der Anaesthesist
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Slices of the rabbit caudate nucleus were incubated with [3H]choline for 30 min and then superfused continuously with Mg(2+)-free medium at 37 degrees C. Stimulation with N-methyl-D-aspartate (NMDA) caused a concentration-dependent release of [3H]acetylcholine (ACh), which was abolished in the presence of MG2+. This release of ACh was exocytotic and mediated by action potentials. ⋯ At the neuropathologic level, Parkinson's disease is characterized by an overshoot of striatal cholinergic transmission due to the decreased inhibitory dopaminergic input from the substantia nigra. The well-known antiparkinsonian effect of memantine and amantadine is most probably due to a blockade of NMDA-receptor-linked ion channels on striatal cholinergic interneurons, leading in turn to a diminished release of ACh. Since ketamine diminished cholinergic neurotransmission to a similar degree to that achieved with memantine and amantadine and even more potently than the adamantanes, and that at concentrations far below those needed for its anaesthetic and analgesic properties, it seems worthwhile to test this drug as an antiparkinsonian agent clinically.
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Randomized Controlled Trial Comparative Study Clinical Trial
[Postoperative warming therapy in the recovery room. A comparison of radiative and convective warmers].
Hypothermia (Tcore < 36 degrees C) can be observed in 60%-80% of all admissions to the post-anaesthetic recovery unit. Effective warming devices may accelerate rewarming, improve patient comfort, and suppress shivering thermogenesis. This study was designed to compare the efficiency of warming devices in extubated postoperative patients and their effect on postoperative oxygen uptake (VO2). ⋯ External rewarming did not reduce the average load (mean VO2). Thus, concerning the goal of accelerating rewarming, it appears more rational to prevent intraoperative heat loss. For a comparison of efficiency of different warming devices, postoperative extubated patients do not appear to be an ideal model for study.
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Knowledge of normal and impaired pulmonary gas exchange is essential to the anaesthesiologist. Analysis of an arterial blood sample allows evaluation of whether or not pulmonary gas exchange is normal. For this purpose comparison with the oxygenation index or the alveolar-arterial PO2 difference is helpful. ⋯ In daily practice, venous admixture or intrapulmonary shunt can be calculated using arterial and mixed-venous blood. By analysing arterial and expired PCO2, dead-space ventilation can be determined, but extended analyses of VA/Q distribution are not possible in daily practice. However, knowledge of the principles of typical disturbances of pulmonary gas exchange in acute and chronic lung disease allows the use of therapeutic strategies based on the pathophysiological changes.
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Comparative Study Clinical Trial
[Inverse fick's principle in comparison to measurements of oxygen consumption in respiratory gases. Does intrapulmonary oxygen uptake account for differences shown by different system methods?].
Automated measurements of respiratory gas exchange recently became available for the determination of oxygen uptake (VO2) in critically ill patients. Whereas these metabolic gas monitoring systems (MBM) are assumed to measure total body VO2, the reversed Fick method in principle excludes intrapulmonary VO2. Previous clinical reports comparing VO2 measured by the reversed Fick principle (VO2Fick) with VO2 measured by MBM (VO2MBM) found that VO2MBM was significantly greater than VO2Fick. ⋯ RESULTS. Neither in the study group nor in the control group could a significant difference between methods be demonstrated. In patients with pneumonia the mean difference between methods (VO2Fick-VO2MBM) was 15.2 ml/min (4.2%); the double standard deviation of differences (2 SD) was 59.2 ml/min (19.2%).