Browsing by Author "Mahfouf, M."
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- Fuzzy modelling for controlled anaesthesia in hospital operating theatresPublication . Nunes, Catarina S.; Mahfouf, M.; Linkens, D.A.Balanced anaesthesia introduces the problem of drug interactions. In this paper, the effect concentrations of anaesthetic and analgesic drugs are used to model the pharmacodynamic interactions of the two drugs on the cardiovascular parameters, and on the auditory evoked potentials. An adaptive network-based fuzzy inference system is used to model the different signals. A stimulus model is used to establish the effects of surgical stimulus on the cardiovascular parameters. This model is constructed into a Mamdani type of fuzzy model, using anaesthetist’s knowledge described by fuzzy IF–THEN rules. Clinical data are used to construct the patient model.
- A fuzzy patient model in anaesthesiaPublication . Nunes, Catarina S.; Mahfouf, M.; Linkens, D. A.Balanced anaesthesia introduces the problem of drug interactions. In this article, the effect concentrations of anaesthetic and analgesic are used to model the pharmacodynamic interactions of the two drugs on the cardiovascular parameters, and on the auditory evoked potentials. An adaptive network-based fuzzy inference system is used to model the different signals. A stimulus model is used to establish the effects of surgical stimulus on the cardiovascular parameters. This model, is constructed into a Mamdani type of fuzzy model, using the anaesthetist knowledge described by fuzzy IF-THEN rules. Clinical data is used to construct the patient model.
- Monitoring and control of unconsciousness during clinical surgery: Auditory Evoked Potentials (AEP) versus the Clinical Gold Standard (CGS)Publication . Mahfouf, M.; Backory, J.; Abbod, M. F.; Nunes, Catarina S.; Linkens, D. A.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 cliche´. This does not, in any way, mean that the subject is trivial or ‘passe´’ 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.
- Multivariable fuzzy control for the simultaneous administration of the anaesthetic and the analgesic drugsPublication . Nunes, Catarina S.; Mahfouf, M.; Linkens, D. A.; Peacock, J.A multivariable fuzzy controller developed for the simultaneous administration of the anaesthetic drug (propofol) and the analgesic drug (remifentanil), is presented. The controller was designed in order to achieve a steady state level of depth of anaesthesia (DOA) and to reduce the amount of drug infused. The multivariable fuzzy controller is based on linguistic rules that interact with three decision tables, one of which represents a fuzzy PI controller. Optimisation using genetic algorithms was used to determine the scaling factors of the fuzzy PI controller. According to the different possibilities for the DOA level and for the surgical stimuli, the multivariable controller defines the required change in the infusion rates of the two drugs. A patient model of the interaction between propofol and remifentanil was used to test the multivariable controller. The controller was able to adjust the remifentanil infusion rate according to the stimulus intensity, and takes advantage of the synergistic interaction to the change adequately the propofol infusion rate. Propofol is titrated to lower infusion rates, decreasing the amount of drug infused, and speeding up recovery. In addition, the controller ensures adequate analgesia by titrating the remifentanil according to stimulus. The multivariable fuzzy controller was tested under different simulations, and responded efficiently to different induction profiles, set point changes and disturbances.