Der Anaesthesist
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In cases of craniofacial and mandibulofacial malformations, which are mostly treated during childhood, difficult intubation conditions must generally be expected. In such cases, the laryngeal mask airway (LMA) an alternative instrument for use in endotracheal intubation is a new aid for ventilation. In certain instances, it can be used alone to induce general anaesthesia. Reports of endotracheal intubation by means of the LMA in adults have also been published. ⋯ Therefore, the LMA is not only a ventilation aid, but also a valuable tool in difficult intubation conditions. In our opinion, it is necessary to provide this tool in every anaesthetic unit.
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Diagnosis of a perioperative myocardial infarction (PMI) on the basis of measurement of the creatine kinase MB fraction (CKMB) alone is not always easy. Surgical traumatisation of muscle fibres can lead to false-positive elevations. Newly introduced laboratory tests for cardiac troponins seem to facilitate the diagnosis of PMI. We measured serum values of cardiac troponin T in 139 patients described in detail in part I and compared them with common diagnostic tools for myocardial infarction. ⋯ Troponin T is a highly specific marker for perioperative myocardial cell necrosis. Patients with raised levels preoperatively seem to be at higher risk for postoperative reinfarction and left ventricular failure. The prognostic value of such an elevation is not clearly defined, especially in patients with chronic renal failure.
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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.
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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.
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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.