Der Anaesthesist
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About twenty years ago, Peter Stewart had already published his modern quantitative approach to acid-base chemistry. According to his interpretations, the traditional concepts of the mechanisms behind the changes in acid-base balance are considerably questionable. The main physicochemical principle which must be accomplished in body fluids, is the rule of electroneutrality. ⋯ Contrary for example, a decrease in [A(-)] (e. g. during hypoalbuminemia) leads to an increase in [Bic(-)] and therefore to an alcalosis (and vice versa). Thus, by Stewart's approach, completely new acid-base disturbances, like "hyperchloremic acidosis" or "hypoalbuminemic alcalosis" (which, of course, can also exist in combination) can be detected, which had been unrecognised by the classic acid-base concepts. Consequently, Stewart's analysis can lead to a better understanding of the mechanisms behind the changes in acid-base balance.
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The following article summarizes different aspects of local anesthetic effects that cannot be explained purely by a sodium channel blockade. Particularly remarkable is hereby their antiinflammatory activity, e.g. the inhibition of pathological changes such as excessive stimulation of the inflammatory system, without compromising the host defense system. ⋯ In addition, local anesthetics are known for their potency to minimize bronchial hyperreactivity, although details of the underlying mechanisms are not yet elucidated. These effects of local anesthetics may represent interesting prospects for which their relevance has to be determined.
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Numerous pathophysiological mechanisms are known to cause nausea or vomiting but their role for postoperative nausea and vomiting (PONV) is not quite clear. Volatile anesthetics, nitrous oxide and opioids appear to be the most important causes for PONV. Female gender, non-smoking and a history of motion sickness and PONV are the most important patient specific risk factors. ⋯ A or an antiemetic is reasonable and only a (very) high risk justifies the combination of several prophylactic antiemetic interventions. For the treatment of PONV an antiemetic should be chosen which has not been used prophylactically. The necessary doses are usually a quarter of those needed for prophylaxis.