Der Anaesthesist
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During sevoflurane anaesthesia cerebral blood flow is preserved or slightly decreased. Cerebral oxygen consumption is reduced to 50% under 1 MAC sevoflurane. Autoregulation of cerebral blood flow and responsiveness of cerebral blood flow to changes in Pa CO2 are widely preserved. ⋯ Recovery of cognitive and psychomotor functions seems to be faster and more complete after sevoflurane than after isoflurane anaesthesia. In inducing seizure like EEG or muscle activity, sevoflurane seems to be comparable with isoflurane. There is no limitation of sevoflurane use in patients with concomitant psychiatric or neurological diseases, and sevoflurane may be valuable addition in neurosurgery or carotid surgery.
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In obstetrics, general anaesthesia is increasingly being replaced by peridural anaesthesia. The cases where general anaesthesia is still used are those involving increased risk. It is therefore not surprising that, for example, maternal mortality in cases of caesarian section under general anaesthesia has not decreased. ⋯ In a comparison of sevoflurane and peridural anaesthesia, there was no difference in outcome for the child and the maternal results showed only the expected procedure-specific differences in circulatory parameters and early postoperative analgesia requirement. A second study involving continuous pEEG monitoring (SEF90) showed advantages of sevoflurane over isoflurane in the initial phase of surgery and in the recovery phase. However, the value of sevoflurane in obstetric anaesthesia will have to be confirmed in more extensive studies.
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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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Propofol is known to possess direct antiemetic effects. Its use for induction and maintenance of anaesthesia has been shown to be associated with a lower incidence of postoperative nausea and vomiting (PONV) when compared to any other anaesthetic drug or technique. ⋯ The possible effects of propofol on the cerebral cortex, its interactions with the dopaminergic and the serotoninergic systems are evaluated by the known clinical and basic science results. Finally, the advantages and disadvantages of using propofol to decrease the incidence of PONV in clinical practice are discussed.
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The cardiovascular effects of sevoflurane are similar to those of isoflurane with some minor exceptions. In contrast to isoflurane and particularly to desflurane, sevoflurane has not been associated with increases in heart rate in healthy volunteers and in patients. ⋯ In several multi-center studies of patients with coronary artery disease or at high risk for coronary artery disease receiving either sevoflurane or isoflurane for either cardiac or non-cardiac surgery, the incidence of myocardial ischemia and infarction did not differ between treatment groups. In both human and animal models, sevoflurane preserves cerebral blood flow and reduces cerebral metabolic rate, much like isoflurane.