Der Anaesthesist
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Randomized Controlled Trial Clinical Trial
[The use of pulse oximetry in prilocaine induced methemoglobinemia].
During the last 15 years pulse oximetry has become a widely accepted method of monitoring during general and local anaesthesia. Pulse oximeters measuring with two wave-lengths are considerably affected by dyshaemoglobin. At concentrations up to 30%, CO-Hb cannot be distinguished from O2-Hb. ⋯ The reasons for the different sensitivity are probably the different algorithms used by the manufacturers. In spite of the good correlations we can not recommend Met-Hb estimation by pulse oximetry measurement with two wave-lengths, because the distinction of hypoxia and Met-Hb its not possible when hyperoxic conditions are not stable as they were in our controlled study. A low psO2 measured in patients with normal arterial blood gases can be an indication of Met-Hb, but the exact measurement of dyshaemoglobin is only possibly by using a co-oximeter.
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Pre-emptive analgesia is based on the idea that analgesia initiated before a nociceptive event will be more effective than analgesia commenced afterwards, and that its effects will outlast the pharmacological duration of action of the analgesic used. The idea of pre-emptive analgesia is based upon experimental neurophysiological work demonstrating that afferent nociceptive impulses result in alterations of central nervous system function. These changes, most easily elicited by C-fibre afferents, particularly affect the spinal dorsal horn. ⋯ Clinical studies have so far only used short-term analgesia. To permit extrapolation from the experimental to the clinical situation, pre-emption in the surgical context must correspond adequately to the duration and extent of the nociception involved. Studies of pre-emptive analgesia in a clinically relevant form, i.e. where nociception and analgesia are correctly matched, are called for.
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Pharmacological praemedication. In patients receiving regional anaesthetics induction of deep sedation prior to the performance of the block should be avoided because during the installation of the nerve block it is an advantage to have a cooperative patient. Adequate anxiolytic effects are achieved by oral administration of chloracepate (0.3-0.5 mg/kg body weight). ⋯ Pulse oxymetric monitoring of the potentially endangered respiratory function is obligatory. The individual transition to general anaesthesia is not easy to determine. Therefore, it is essential that, whenever the need arises, intubation and mechanical ventilation intervention procedures be carried out immediately.
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The goal of therapy in patients with severe head injury is to avoid secondary brain damage. Analgesia and sedation are an essential part of the therapy, and several drugs are in current use. However, few controlled clinical trials have been performed so far, and none of these drugs has proved to be superior. ⋯ More clinical studies are warranted. Gamma-hydroxybutyrate (GHB) is a physiological substance, which has only sporadically been investigated for sedation in patients with head trauma. The few available studies show beneficial res
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Randomized Controlled Trial Clinical Trial
[The effect of puncture needle on the subarachnoid catheter position in continuous spinal ansthesia].
The subarachnoid position of the microcatheter has an impact on the outcome of continuous spinal anaesthesia (CSA). The present prospective, randomised study investigated the influence of two different spinal needles on the radiographically documented subarachnoid positions of microcatheters in CSA. In addition, the influence of the subarachnoid position of the microcatheter on onset time of analgesia, dose requirement of local anaesthetics, and level of analgesia was examined. ⋯ CONCLUSIONS. Sprotte needles provide a higher number of cranially directed microcatheters, which are associated with faster onset of analgesia, lower dose requirement of local anaesthetics, and higher analgesic levels in CSA. The results suggest more effectiveness and probably more safety in microcatheter CSA using Sprotte needles for catheter insertion.