Der Anaesthesist
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The main cause for the rise in cuff-pressure during anesthesia is the diffusion of nitrous oxide into the tube cuff. Gas-diffusion induced pressure changes in low pressure-high volume cuffs are registered continuously. Exposure of an air-filled cuff into an anaesthetic gas atmosphere in vitro shows, that there is an increase in cuff-pressure up to 150 mm Hg within 8 hours. ⋯ In intubated patients cuff-pressure increases even more. During anesthesia lasting 4--5 hours we recorded pressures up to 150 mm Hg, too. To prevent these high pressures we recommend the reducing of cuff-volume within defined times of anesthesia or, alternatively, the use of the anesthetic gas mixture as cuff inflating gas.
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The aim of the present investigations was to see, if halothane (h), enflurane (e), isoflurane (i), and methoxyflurane (m) exert cytostatic or cytotoxic effects. The experiments were performed on suspension cultures of an established line of Ehrlich ascites tumor cells, which were gased by a mixture of N2 (78%), O2 (20%), and CO2 (2%) to which the volatile anaesthetics in 5 different concentrations were added by vaporizers. Under standardized conditions (incubation time: 24 or 48 hrs; initial cell density: 2 X 10(5) cells/ml culture medium) the following results were obtained: 1. ⋯ With exception of m, which produced a significant decrease of the cellular protein content in the dose range 1.5-2.0 vol% and of the cellular DNA content in all concentrations applied the 3 other anaesthetics caused an increase of the cellular protein content and a somewhat smaller increase of the cellular nucleic acids content. The obtained results indicate that the effect of anaesthetic agents on dividing cells is not due to the same mode or site of action, but to an influence on different stage of the cell cycle, particularly the interphase. Colchicine-like c-mitosis were not obtained.
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During a three year period, pediatric patients 4 to 16 years old were post-operatively screened for anaesthesia-induced myoglobinuria. All investigated cases had general anaesthesia and received succinylcholine prior to intubation. Anaesthetics were predominantly performed for tonsillectomies and/or adenoidectomies. ⋯ Anaesthesia-induced myoglobinuria occurs more often than previously presented. This abnormal reaction to succinylcholine is not harmless in all cases. The possible genetic influence on total CPK and its isoenzymes is discussed.
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An intravenous infusion scheme was established in five healthy volunteers on the basis of pharmacokinetic analysis as described by J. G. Wagner. ⋯ An infusion model was developed for a therapeutic plasma concentration of 0.5 microgram/ml etomidate. An initial fast constant-rate infusion (8 mg/min) was followed by an infusion with 0.8 mg/min for the entire duration of the application. The measured plasma levels coincided fairly well with the predicted steady state plasma levels and were accompanied by a distinct hypnotic effect in all volunteers.