Articles: closed-circuit-anesthesia.
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Anesthesia and analgesia · Apr 2005
Randomized Controlled Trial Clinical TrialNon-zero basal oxygen flow a hazard to anesthesia breathing circuit leak test.
The non-zero basal flow (BF) of oxygen in anesthesia machines has been set to supply the basal metabolic requirement of oxygen. However, there is no scientific evidence of its necessity. In this study we sought to clarify whether non-zero BF affects leak detection during preanesthetic inspections. ⋯ The leak detection rate of leak test with BF was less than without BF (P < 0.01). We demonstrated that non-zero BF of oxygen decreases the leak detection rate and is an obstacle for leak detection, especially for small leaks. Therefore, we recommend that breathing circuit leak tests should be performed in the absence of BF of oxygen.
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The aim of this study was to detail the time-course, defined as the changes in end-tidal drug concentration with time, and consumption of inhaled anaesthetics when using a multifunctional closed-circuit anaesthesia machine in various drug delivery modes, and to compare it with a classical anaesthesia machine using an out-of-circle vaporizer under high and low fresh gas flow conditions. ⋯ A combination of the fastest time course and lowest consumption of sevoflurane and desflurane was found when using the Zeus apparatus in AC uptake mode.
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In order to reduce losses of gases through plastic components and to reduce nitrogen accummulation during closed system anaesthesia we investigated either 10 sets of anaesthetic tubing made of silicon as used in standard clinical practice and 10 sets made of latex, which are not used anymore due to concerns about latex allergies. The results were compared to each one set made of conventional industrial rubber. ⋯ If closed anaesthetic systems in the future will be used in intensive care therapy or in case of long lasting procedures in which closed system anaesthesia is proceeded, materials other than silicone should be investigated to avoid regular purging of system and consecutive losses of gas mixtures.
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Randomized Controlled Trial Comparative Study Clinical Trial
A new closed-loop control system for isoflurane using bispectral index outperforms manual control.
Automatic control of depth of hypnosis using the Bispectral Index (BIS) can help to reduce phases of inadequate control. Automated BIS control with propofol or isoflurane administration via an infusion system has recently been described, a comparable study with isoflurane administration via a vaporizer had not been conducted yet. Our hypothesis was that our new model based closed-loop control system can safely be applied clinically and maintains the BIS within a defined target range better than manual control. ⋯ Closed-loop control with BIS using isoflurane can safely be applied clinically and performs significantly better than manual control, even in phases with abrupt changes of stimulation that cannot be foreseen by the control system.