Der Anaesthesist
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Sevoflurane is characterized by a low blood/gas partition coefficient of 0.69, only desflurane and nitrous oxide have lower blood/gas solubilities. Alveolar equilibration is fast, a feature useful for rapid induction of anesthesia. Because of its pleasant smell, mask induction is feasible and routinely used in clinical settings. ⋯ Pulmonal elimination of sevoflurane is rapid because of its low blood solubility. Clinical results showed that rapidity of recovery from sevoflurane anesthesia is equal to that of desflurane anesthesia. Physicochemical properties of sevoflurane allow its application in conventional vaporizers.
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The low blood/gas solubility, the rapid uptake and nonpungent odor permits mask induction with sevoflurane in adults. Depending on the induction techniques (tidal breathing, deep breaths or single-breath induction), the use of nitrous oxide and the concentration of inspired sevoflurane anesthesia can rapidly be induced within 41-178 s. Adverse effects like coughing, breath-holding or increased secretions occur with a low incidence of 2%-20%. ⋯ Although hypoxic pulmonary vasoconstriction is directly inhibited by volatile anesthetics in in vitro studies, this effect is usually of minor clinical consequence. The use of volatile anesthetics may be advocated because of their salutory effects on bronchomotor tone, high potency (allowing high inspired concentration of oxygen while avoiding awareness) and rapid adjustment of anesthetic depth. Sevoflurane possesses these attributes and may be useful for OLV.
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Sevoflurane, like all currently used volatile anaesthetics, is degraded by carbon dioxide absorbents. The most significant degradant is a haloalkene known trivially as "compound A". Compound A is nephrotoxic in rats and, at higher doses, in nonhuman primates, causing proximal tubular necrosis. ⋯ There have been no case reports of compound A-associated renal injuryin humans. In volunteers, one study found changes in experimental but not conventional renal markers, while other investigations show no significant changes in either standard or experimental markers. The mechanism of compound A nephrotoxicity in rats appears to involve metabolism to glutathione and cysteine conjugates, and their subsequent renal uptake and metabolism by pathways that are different in rats and humans.
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The total costs for a department of anaesthesia amount to a fraction of the total hospital budget that is proportional to the overall number of hospital departments; this means anaesthetic departments are in general not cost drivers. In the analysis of perioperative costs, anaesthesia accounts for about 10-15% of the total costs for the complete hospital stay, the exact proportion depending on the type of surgery. In the analysis of costs for the intraoperative period alone anaesthesia personnel contributes about 20%, and material costs about 10% of the total costs, while inhalational agents account for less than 1%. ⋯ The question of whether these effects and side effects translate into cost differences between agents depends largely on local factors, e.g., patient case mix, staffing, policy of discharge from the postanaesthetic care unit, and many others. We conclude that volatile anaesthetics account for only a minor portion of the budgets in the anaesthesia department and the hospital overall. The higher market price for the new agents that result in higher costs per MAC-hour may be compensated for by the economic impact of the fewer side effects and the shorter postanaesthesia stay in the hospital.
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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.