Der Anaesthesist
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Biography Historical Article
[Early contributions from Erlangen to the theory and practice of ether and chloroform anesthesia. 1. Heyfelder's clinical trial with ether and chloroform].
The era of modern anaesthesia in Germany began on January 24th, 1847. This day, professor in ordinary Johann Ferdinand Heyfelder anaesthetized a patient with sulphuric ether in the clinic of surgery and ophthalmology of the University of Erlangen. By March 17th, 1847, Heyfelder had performed 121 surgical procedures under ether. ⋯ Moreover its application was much easier for it needed no special apparatus. However, because of its great anaesthetic potency, Heyfelder particularly demanded great caution in the application of chloroform. Explicitely he expected an assistant for chloroformizations, whose only duty was to supervise the inhalations and the patient--a forerunner of the modern specialized anaesthesiologist.
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Sevoflurane breaks down in basic environments to form a vinyl ether known as Compound A. This compound is toxic in the rat, with an LC50 of about 400 ppm after 3 h exposure and with renal damage evident between 50 and 100 ppm. There is no valid current evidence that Compound A is toxic in man, and the rat may not be an appropriate model for determination of this breakdown product's toxic potential in humans. The main factors influencing the degree of patient exposure to Compound A include fresh gas flow, sevoflurane concentrations, absorber temperature and composition, and the patient's carbon dioxide production.
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Randomized Controlled Trial Multicenter Study Clinical Trial
[Comparison of sevoflurane and isoflurane in ambulatory surgery. Results of a multicenter study].
A multicenter, randomized, comparative phase III study evaluating the effect of sevoflurane versus isoflurane in adult outpatients was performed. The aim of the study was to compare (1) maintenance of anaesthesia and (2) how rapidly and easily the patients emerge from the anaesthetic and recover. ⋯ Sevoflurane was as safe as isoflurane for anaesthesia in adult outpatients. Patients who received sevoflurane had statistically significantly shorter recovery parameters than isoflurane patients.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
[The cardiovascular effects of sevoflurane].
The cardiovascular effects of sevoflurane as published from clinical and experimental studies are reviewed with respect to general haemodynamics and organ perfusion. Sevoflurane appears to be quite similar to isoflurane, with some minor exceptions. In adult patients and volunteers, sevoflurane has not been associated with increases in heart rate, whereas isoflurane and desflurane caused significant increases in heart rate at higher concentrations. ⋯ In several multi-center studies where patients with coronary artery disease or at high risk for coronary artery disease were randomised to receive either sevoflurane or isoflurane for cardiac or non-cardiac surgery, the incidence of myocardial ischaemia 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. Considering its favourable pharmacokinetic properties, the introduction of sevoflurane into clinical practice appears to be a promising extension of the anaesthetic spectrum.
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Midlatency auditory evoked potentials (MLAEP) are suppressed dose-dependently during anaesthesia with a variety of general anaesthetics. Therefore, MLAEP have been proposed to measure depth of anaesthesia and to indicate intraoperative awareness. Several studies give evidence of a close relationship between MLAEP and motor signs of wakefulness, intraoperative awareness, and explicit and implicit memory functions during general anaesthesia. ⋯ The new volatile anaesthetic sevoflurane leads to a dose-dependent increase in MLAEP peak latencies and a decrease in MLAEP amplitudes. At about 1.5 vol.% end-expiratory sevoflurane concentration, MLAEP are significantly suppressed and Nb latency is in the range of 68-80 ms. Therefore, from the present data and those from the literature, one may expect that sevoflurane at concentrations greater than 1.5 vol.% for general anaesthesia would be able to suppress awareness phenomena such as purposeful movements, auditory perception, intraoperative wakefulness and awareness, memory formation, and explicit and implicit recall of intraoperative events.