Der Anaesthesist
-
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.
-
Review Comparative Study
[Nephrotoxicity and fluoride from the viewpoint of the nephrologist].
Fluoride released from methoxyflurane (MOF) during its hepatic and extrahepatic metabolism has been regarded as the major culprit responsible for MOF-induced nephrotoxicity. In the isolated, perfused rat kidney model, admixture of 1500 mumol/l fluoride to the perfusate resulted in tubular and glomerular damage with concomitant anuria. Fluoride administration in Fischer 344 rats in vivo elicited a renal diabetes insipidus-like syndrome that had also been observed in patients after MOF anaesthesia. ⋯ The degree of nephrotoxicity correlates loosely with maximal serum fluoride levels, but can probably be modulated by further factors like intrarenal in situ formation of fluoride, urinary pH and flow, and especially, the presence of other nephrotoxins. This mitigates the importance of maximal fluoride serum levels, especially the 50 mumol threshold, as predictors of clinically relevant nephrotoxicity. To date, no nephrotoxic effects of sevoflurane could be demonstrated.
-
Case Reports
[Treatment reduction in intensive care. "Allowing the patient to die" by conscious withdrawal of medical procedures].
The conversion of an "attempt to treat" to "prolongation of dying" represents an important problem in modern intensive care. If the actual or presumed will of the patient is unknown, the physician has to decide about the extent of treatment in a paternalistic manner. In these difficult decisions the physician has to consider prognosis, and certainty of prognosis and has to carefully balance between the right to live and the right to die. ⋯ If the situation is hopeless and further medical interventions are futile, then allowing the patient to die by therapy reductions is not only a possibility but a mandatory act of humanity. In that case it does not matter whether new treatment modalities are abandoned or whether already instituted medical measures are withdrawn. In clinical practice, however, the "fine tuning" of therapy reduction has to be tailored to the individual case and largely depends on prognostic certainty.
-
The inhalational anaesthetic fluor-methyl-trifluor-1-(trifluoromethyl)-ethylether sevoflurane has been known for more than 20 years and is structurally related to the currently available volatile anaesthetics. This anaesthetic is characterized by a low blood/gas partition coefficient of 0.69 and high fat solubility, leading to a sharp rise in alveolar concentration and quick anaesthesia induction. As opposed to desflurane, sevoflurane does not boil at ambient temperature, thus making a special vaporizer unnecessary. ⋯ As opposed to methoxyflurane, which may be nephrotoxic due to its microsomal metabolism in kidney tissue, sevoflurane does not seem to cause clinical inhibition of renal function even at plasma fluoride levels above 50 mumol/l, a concentration thought to be associated with renal tubular impairment. A possible reason for this observation is lower metabolism of sevoflurane within renal tissues. Due to its quick onset and fast elimination, sevoflurane is an interesting new volatile anaesthetic offering various clinical advantages.
-
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.