Monitoring and control of unconsciousness during clinical surgery: Auditory evoked potentials (AEP) versus the clinical gold standard (CGS)

Abstract

Much has been said and written about the 'monitoring' and 'control' of depth of anaesthesia (DOA) in the last three decades or so, so much that the theme itself is becoming rather cliché. This does not, in any way, mean that the subject is trivial or 'passé' but merely reinforces the fact that it is rather challenging and full of pitfalls since it can also form the ideal test-bed for hardware/software innovations relating to signal processing and closed-loop control. While this was taking place in the four corners of the world, the medical as well as the engineering research communities were learning more and more of how far they could stretch the boundaries of such technologies in clinical situations when it came to achieving 'adequate anaesthesia'. In order to explore the powerful dichotomy associated with monitoring and control this paper will attempt to take the reader on an exploration journey, which starts with a rather simplistic (conservative) approach to closed-loop control of DOA via the monitoring of arterial blood pressure (the clinical gold standard-CGS approach or part of) followed by the more involved 'route', which implicates the use of audio-evoked potentials, which are normally extracted from the EEG signals. In addition to highlighting the merits/limitations of the above two techniques, this paper will also identify a list of worthwhile pointers to future research in monitoring and control of DOA.

Towards automation in anaesthesia: A review

“…In contrast, [29] uses signal do noise reduction techniques based on simulations and the underlying characteristics of the AEP. [30] is the most recent work with AEP processing, It shows multi-resolution wavelet analysis as a feature extraction method from recorded AEPs during anaesthesia. The combination of these features with a fuzzy logic rule-based inference has been shown to successfully predict the underlying DOA remarkably well.…”