Articles: closed-circuit-anesthesia.
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It is a strange contradiction that increasingly sophisticated anaesthesia machines are developed meeting all requirements for rebreathing techniques and the highest safety standards, but the usual anaesthetic management is still based on the use of fresh gas flows that preclude substantial rebreathing. The advantages of rebreathing can only be realised if low-flow anesthesia techniques are adopted. Increasing acceptance of these methods is due to the availability of comprehensive anaesthetic gas monitoring. ⋯ The use of new inhalational anaesthetics such as desflurane that require comparatively high concentrations, or even xenon, will motivate to sparing use. Increasingly stringent health and safety regulations as well as sharpened ecological awareness will prompt anaesthetists to minimise all anaesthetic gas emission according to the possibilities of available equipment. Last but not least, the demand for economical working methods will be an argument for applying low-flow anaesthesia techniques.
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The purpose of this report is to describe a potentially hypoxic event which occurred during mask induction with the Bain circuit in a healthy. ASA I boy. Failure of induction occurred because a pop-off weight from a bubble bottle was lodged in the elbow connecting the Bain circuit to the mask and prevented gas flow. ⋯ Such an anaesthetic mishap could occur with any breathing circuit which is re-used. Although there was no serious misadventure, the potential for an hypoxic complication with either intra-venous induction of anaesthesia, or dislodging of the weight into the airway was significant. We conclude that the standard tests of system patency do not ensure safety.
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Sevoflurane reacts with CO2 absorbents, resulting in the generation of breakdown products. The concentrations of sevoflurane breakdown products in a low-flow system within 5 h have been reported, but concentrations in low-flow anesthesia exceeding 5 h or in closed-circuit anesthesia have not. In this study, the breakdown products of sevoflurane in closed-circuit anesthesia exceeding 5 h were examined. ⋯ Two breakdown products were detected in the patients anesthetized with sevoflurane using a closed-circuit technique. No abnormalities were observed during anesthesia, and no evidence of hepatic or renal dysfunction was noted in postoperative laboratory tests.
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Anaesthesiol Reanim · Jan 1994
Comparative Study[Anesthesia with the closed PhysioFlex system in comparison with conventional anesthesia procedures].
So far the anaesthetic technique of the closed circuit system in clinical routine could not be used adequately, because suitable mixtures of respiration gas components were not available and the maintenance of a sufficient gas volume in the anaesthetic circle system was not possible with the standard anaesthesia machines. The anaesthesia machine PhysioFlex was especially constructed to deliver anaesthetics in a closed circuit system. In this anaesthesia machine the concentrations of the respiratory gases and the gas volume in the circle system are automatically controlled by a feedback mechanism. ⋯ After the induction the desired inspiratory oxygen-concentration was reached within 5 minutes, the expiratory isoflurane-concentration within 10 minutes in the CC group and was maintained reliable. The consumption of liquid isoflurane was 12.9 ml/h in the HF group, 7.5 ml/h in the LF group and 5.3 ml/h in the CC group. The anaesthetic management was possible without any problems in all three groups.