Der Anaesthesist
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Object of this review is to present the physiological principles, diagnostic techniques and therapeutic options that are related to modifications of oxygen delivery in sepsis. Despite intense research activities in this area, many topics regarding oxygen transport and oxygen consumption in sepsis are still not clear. For example, the often discussed shift of the critical value of oxygen delivery to higher values in sepsis has not been proven, yet. ⋯ Until now, it was not shown, whether the increase of oxygen delivery to supranormal levels reduces mortality in septic patients. It is also unknown, which catecholamine and which infusion solution is suitable for the treatment of septic patients. In future further research is necessary to solve the problems associated with sepsis therapy.
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The volume of preoperative screening investigations for outpatient anaesthesia ranges from few, selectively ordered investigations to extensive routine diagnostic procedures. It seem appropriate to reevaluate benefit and efficacy of routine preoperative assessment programs. The purpose of preoperative diagnostic is to assess the risk of anaesthesia and surgery for the patient. ⋯ The anaesthetist must be sufficiently informed in time to assess the perioperative risk of the patient and to alter anaesthetic management as necessary. According to the presented studies a clinical history and a through physical examination represent an effective method of screening for the presence of disease. Careful medical history evaluation and physical examination can avoid extensive investigations in apparently healthy individuals and the latter should only be ordered if indicated.
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Due to its low solubility and the high maximum concentration delivered by the vaporizer sevoflurane is especially suitable for the performance of low flow anaesthetic techniques. High flow phases for wash-in or wash-out of anaesthetic gases can be kept short, the difference between the volatile's concentration in the fresh gas and within the breathing system is comparatively small, and the time constants are short even during low flow anaesthesia. The monitoring, required to sufficiently ensure the safety of the patients, corresponds to the current obliging technical safety standards. ⋯ Thoroughly the use of sevoflurane with dry soda lime must be avoided, as this volatile in an extreme exothermic reaction is absorbed nearly totally and degraded to a considerable degree by dry carbon dioxide absorbent. The gaseous degradation products are pungent and possibly may be harmful to the patients. Only by low flow anaesthesia the use of sevoflurane will gain an economically and ecologically acceptable range of efficiency.
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Sevoflurane is a viable alternative to propofol and desflurane for both induction and maintenance of general anaesthesia in the ambulatory setting. As a result of sevoflurane's lack of respiratory irritant properties, it provides for a smooth induction and prompt emergence from outpatient anaesthesia. In addition, the relatively low incidence of post-operative nausea and vomiting facilitates "fast-tracking" after ambulatory surgery. Although no single anaesthetic agent is ideal, when sevoflurane is combined with other adjunctive drugs it can produce excellent surgical conditions for a wide variety of ambulatory surgical and diagnostic procedures.
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There are a number of assays available to study genetic toxicity of inhalation anaesthetics. Those discussed in this review are the Ames Salmonella mutagenesis test and assays for structural chromosome aberrations, micronuclei (MN) and sister chromatid exchanges (SCEs). None of these assays showed abnormalities induced by volatile inhalation anaesthetics. ⋯ Under these conditions occupational exposure is low even when using laryngeal mask airways and uncuffed tracheal tubes. Sevoflurane is a halocarbon, but is only partially halogenated and the only halogen it contains is fluorine. Sevoflurane, therefore, appears to have an insignificant effect on ozone depletion and its contribution to the greenhouse effect is negligible.