Journal of clinical monitoring and computing
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J Clin Monit Comput · Jan 2002
Application of artificial neural networks as an indicator of awareness with recall during general anaesthesia.
Awareness with recall is a rare but serious complication of general anaesthesia with an incidence ranging from 0.1%-0.7%. In the absence of a reliable depth-of-anaesthesia monitor, attempts have been made to predict awareness from intraoperative haemodynamic monitoring data, with little success. Artificial neural networks can sometimes detect relationships between input and output variables even when conventional methods fail. Therefore, we subjected standard intraoperative monitoring data to both artificial neural models and conventional statistical methods in an attempt to predict awareness with recall. ⋯ A prediction indicating awareness by the network is very suggestive of true awareness and recall. Blood pressure and heart rate are significantly higher on average in patients with awareness than in patients without. In an individual patient, however, none of our artificial neural models can detect awareness sufficiently reliably.
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In mechanically ventilated patients the expiratory time constant provides information about respiratory mechanics. In the present study a new method, fuzzy clustering, is proposed to determine expiratory time constants. Fuzzy clustering differs from other methods since it neither interferes with expiration nor presumes any functional relationship between the variables analysed. Furthermore, time constant behaviour during expiration can be assessed, instead of an average time constant. The time constants obtained with fuzzy clustering are compared to time constants conventionally calculated from the same expirations. ⋯ In mechanically ventilated patients, expiratory time constant behaviour can be accurately assessed by fuzzy clustering. A good correlation was found between time constants obtained with fuzzy clustering and time constants obtained by conventional analysis. On the basis of the time constants obtained with fuzzy clustering, a clear distinction was made between patients with and without
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The World Wide Web is increasingly important for medical education. Internet served pages may also be used on a local hard disk or CD-ROM without a network or server. This allows authors to reuse existing content and provide access to users without a network connection. ⋯ Issues include file names, relative links, directory names, default pages, server created content, image maps, other file types and embedded programming. With care, it is possible to create server based pages that can be copied directly to CD-ROM. In addition, Web pages on CD-ROM may reference Internet served pages to provide the best features of both methods.