Articles: closed-circuit-anesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Emergence respiratory complications in children: a comparison between halothane and isoflurane.
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Use of a closed rebreathing circuit for anesthesia delivery offers several advantages: conservation of anesthetic agent, natural heating and humidification of inspired gases, less pollution, and improved monitoring. However, the technique requires careful control of the fresh gas and anesthetic delivery. An anesthesia delivery system has been developed which automatically controls fresh gas delivery, anesthetic delivery, and ventilation in order to regulate circuit volume, oxygen concentration, end-tidal anesthetic concentration, and end-tidal PCO2. ⋯ No further tuning was required for any of the other patients or controllers. During abdominal surgery, the end-tidal bellows position measurement and end-tidal anesthetic concentration measurement increased in variability. The cause of the variability and its elimination are discussed in the article.
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Anasth Intensivther Notfallmed · Feb 1990
Clinical Trial Controlled Clinical Trial[Fresh gas flow and artificial respiration in anesthesia. Technical requirements for the adequate use of rebreathing systems].
The majority of modern anaesthetic machines is designed for the rebreathing method. But frequently high fresh gas flows are employed, thus minimising the rebreathing fraction of expiratory gases. However, only by reducing the fresh gas flow substantially, the advantages of the rebreathing technique can be obtained. ⋯ The minute volume decreased markedly and significantly in the SULLA 808 group, whereas it remained nearly unchanged in the AV 1, the ELSA, and the VIVOLEC groups. The differences result from different modes of fresh gas delivery into the breathing circuit. If anaesthetic apparatus that maintain their tidal volume with different fresh gas flow rates are employed, rebreathing systems may be used judiciously by changing the fresh gas flow according to the individual uptake or any particular clinical requirement.
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Anasth Intensivther Notfallmed · Feb 1990
[Characteristics of the relative humidity and temperature in the inspiratory part of the Dräger circle system and their influence on the function of the ciliary epithelium].
Changes in relative humidity and temperature of the anaesthetic gases were measured in the inspiratory limb of the Dräger circle system next to the carbon dioxide absorber in 29 patients requiring ENT surgery under general anaesthesia. Immediately following intubation and prior to extubation, nasal and tracheal cytologic samples were taken with a brush technique and ciliary beat frequency was determined. At a fresh gas flow of 6 l/min, relative humidity increased from 57.6 +/- 1.5 to 62.5 +/- 1.8% (p less than 0.05) after 110 minutes. ⋯ Ciliary beat frequency remained unchanged at the end of anaesthesia as compared to control in tracheal as well as in nasal samples. It is concluded that the output of relative humidity and temperature in the circle system is not sufficient to prevent broncho-epithelial damage. Ciliary beat automaticity appears to behave according to an all or nothing principle.