Der Anaesthesist
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Postoperative nausea and vomiting (PONV) are still frequent side-effects after general anaesthesia. These unpleasant symptoms for the patients can be sufficiently reduced using a multimodal antiemetic approach. However, these efforts should be restricted to risk patients for PONV. Thus, predictive models are required to identify these patients before surgery. So far all risk scores to predict PONV are based on results of logistic regression analysis. Artificial neural networks (ANN) can also be used for prediction since they can take into account complex and non-linear relationships between predictive variables and the dependent item. This study presents the development of an ANN to predict PONV and compares its performance with two established simplified risk scores (Apfel's and Koivuranta's scores). ⋯ The improved predictive accuracy achieved by the ANN is clinically relevant. However, the disadvantages of this system prevail because a computer is required for risk calculation. Thus, we still recommend the use of one of the simplified risk scores for clinical practice.
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Regardless of their specific physico-chemical properties and chemical structures, all local anaesthetic agents block neuronal voltage-gated sodium channels, and thus suppress conduction in peripheral nerves. Since these ion channels ubiquitously appear in excitable membranes, systemic accumulation of local anaesthetic agents may affect the functional integrity of these structures. Clinically, local anaesthetic-induced systemic toxicity results in central nervous and cardiovascular malfunction. ⋯ In order to avoid systemic accumulation of local anaesthetic agents, several safety procedures have to be considered during the application of these drugs. The treatment of systemic toxicity is strictly dependent on the expression of symptoms. However, hypoxia and acidotic episodes must be avoided and must be treated aggressively.
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Chewing gum is a common habit. Based on two cases of esophageal obstruction during induction of general anesthesia, the importance of chewing gum for anesthesiology is outlined. ⋯ In the case of an obstacle in the oesophagus when inserting a nasogastric tube, an obstruction by a mass of chewing gum should be considered. Although the literature provides differing statements concerning the volume and acidity of gastric juice after chewing gum, the use of chewing gum should be included in preanesthetic NPO rules.