Der Anaesthesist
-
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.
-
The advantages of the addition of low-dose sufentanil to local anaesthetics in epidural analgesia during labour (improvement of analgesia, reduction of total dose of local anaesthetic, reduction of rate of instrumental delivery outweigh) far the disadvantages (pruritus, sedation, potential maternal and neonatal respiratory depression). In over 8000 cases, the addition of incremental sufentanil (7.5 micrograms) up to 30 micrograms has not caused any negative effects on newborns, and hence, the addition of sufentanil is justified; it may even be indicated. Sufentanil has not yet been registered for epidural analgesia in Germany, in contrast to other countries. ⋯ Pain during labour is no absolute indication for the addition of sufentanil, but there are considerable arguments for its superiority in comparison to other standard procedures: the side effects and complications are very limited. Justification of this method is relatively easy in view of the fact that sufentanil has already been registered for peridural analgesia in obstetrics in many other countries. Last but not least, the patient must give informed consent before any procedure can be performed.
-
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.
-
Cannulation of the axillary vein is claimed to be an effective and relatively safe access to the central venous (CV) system [2, 4, 5, 8]. However, anatomical landmarks recommended for venous location (Muskulus pectoralis minor, processus coracoideus) are probably hard to identify in the majority of intensive care (ICU) patients. This investigation evaluated unidirectional 8 MHz Doppler ultrasound (US) in locating the axillary vein. ⋯ Although ethical reasons did not allow a randomised comparison with the standard technique, location of the axillary vein by Doppler US is likely to improve cannulation results and reduce complications induced by "blind" needle probing. With a low US intensity score, the rate of successful punctures is lower and complication rates increase. In some patients, e.g., those with extended tumour operations involving the head and neck, CV access via the axillary vein may be of high clinical value.