Journal of clinical monitoring and computing
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Although feedback control and automation has revolutionized many fields of human activity, it has yet to have a significant impact on healthcare, particularly when a patient is in the loop. Although there have been a number of studies concerned with closed-loop control of anesthesia, they have yet to have an impact on clinical practice. ⋯ Concepts such as modelling for control, feedback and uncertainty, robustness, feedback controller such as proportional-integral-derivative control, predictive control and adaptive control are briefly reviewed. Finally we discuss the safety issues around closed-loop control and discuss ways by which safe control can be guaranteed.
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J Clin Monit Comput · Feb 2014
An enriched simulation environment for evaluation of closed-loop anesthesia.
To simulate and evaluate the administration of anesthetic agents in the clinical setting, many pharmacology models have been proposed and validated, which play important roles for in silico testing of closed-loop control methods. However, to the authors' best knowledge, there is no anesthesia simulator incorporating closed-loop feedback control of anesthetic agent administration freely available and accessible to the public. Consequently, many necessary but time consuming procedures, such as selecting models from the available literatures and establishing new simulator algorithms, will be repeated by different researchers who intend to explore a novel control algorithm for closed-loop anesthesia. ⋯ This simulator could be a benchmark-testing platform for closed-loop control of anesthesia, which is of great value and has significant development potential. For convenience, this simulator is termed as Wang's Simulator, which can be downloaded from http://www. AutomMed.org .
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J Clin Monit Comput · Dec 2013
Case ReportsLeakage of sevoflurane from vaporizer detected by air monitoring system: a case report.
Leakage of inhalational anesthetic gases is an important issue not only to staff health but awareness during general anesthesia. After inhalation of sevoflurane commenced, the audible and visible alarm of our custom-made air monitoring system was activated. The system measured 2-4 ppm of sevoflurane. ⋯ After changing inhalational anesthesia to intravenous anesthesia, the concentration of sevoflurane decreased immediately to zero. The filling level on the vaporizer decreased faster than usual. A thorough check of the vaporizer after surgery identified a worn down seal in the filling device of the vaporizer.
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J Clin Monit Comput · Dec 2013
Quantification of the proportion of motor neurons recruited by transcranial electrical stimulation during intraoperative motor evoked potential monitoring.
Transcranial motor evoked potentials (TcMEPs) are widely used to monitor motor function during spinal surgery. However, they are much smaller and more variable in amplitude than responses evoked by maximal peripheral nerve stimulation, suggesting that a limited number of spinal motor neurons to the target muscle are excited by transcranial stimulation. The aim of this study was to quantify the proportion of motor neurons recruited during TcMEP monitoring under general anesthesia. ⋯ The average ratios (test:control) were 17.1 % (range 1.8-38 %) for the amplitudes and 21.6 % (range 2.9-40 %) for the areas. The activity of approximately 80 % of the motor units to the target muscle cannot be detected by TcMEP monitoring. Therefore, changes in evoked potentials must be interpreted cautiously when assessing segmental motor function with TcMEP monitoring.