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EEG-controlled closed-loop dosing of propofol in rats

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Presentation on theme: "EEG-controlled closed-loop dosing of propofol in rats"— Presentation transcript:

1 EEG-controlled closed-loop dosing of propofol in rats
Tzabazis A , Ihmsen H , Schywalsky M , Schwilden H   British Journal of Anaesthesia  Volume 92, Issue 4, Pages (April 2004) DOI: /bja/aeh102 Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

2 Fig 2 Performance of the feedback control expressed as the ratio of the measured effect and the set point. Each line represents one case. Time is given in minutes since the start of closed-loop control. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

3 Fig 3 Worst case and best case in this study. Time is given in minutes since the start of closed-loop control. The grey line shows the time course of the modified median frequency (mMEF); the black line depicts the cumulative dose of propofol. The set point of 3.0 (0.5) Hz is indicated by the dashed lines. MDPE, median performance error (PE); MDAPE, median absolute PE; D, divergence of the absolute PE; W, wobble of the PE. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

4 Fig 4 Cumulative doses for each animal during closed-loop infusion of propofol. The bold line represents the mean for all rats. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

5 Fig 5 Distribution of the individual effective therapeutic infusion rates (dots) for an effect of modified median frequency (mMEF)=3.0 (0.5) Hz and fitted to a normal distribution function (line). ED50, ED75 and ED95 (see text) can easily be derived from the plot. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

6 Fig 6 Typical EEG signals (one epoch of 8 s each) observed in rats: (1) before propofol administration the EEG was characterized by high activity in the α and β band; (2) at a propofol infusion rate of 0.3 mg kg−1 min−1 the EEG activity was shifted to lower frequencies; (3) at a propofol infusion rate of 0.6 mg kg−1 min−1 propofol spike patterns occurred. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions

7 Fig 1 Experimental setup. A surrogate parameter for anaesthetic depth is derived from the measured EEG and serves as an input for the control algorithm for propofol administration. The control algorithm consists of an adaptive pharmacokinetic/dynamic (PK/PD) model. The infusion rate is determined from the measured effect and the set point as defined by the user. British Journal of Anaesthesia  , DOI: ( /bja/aeh102) Copyright © 2004 British Journal of Anaesthesia Terms and Conditions


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