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US 2002/0117176 A1Published application
Anaesthesia control system
AssigneeThe University Court of the University of Glasgow
InventorsHaralambos Mantzaridis, Gavin N.C. Kenny
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AssigneeThe University Court of the University of Glasgow
InventorsHaralambos Mantzaridis, Gavin N.C. Kenny
Estimating the term…
A system and method to obtain (19) unipolar EEG signals from electrodes (13) attached to a patient's head (14). The EEG signals are detected by the electrodes and transmitted over a patient cable (16) to the EEG data acquisition and analysis system (12). The system (12) generates all power spectrum, bispectrum, and higher-order spectrum arrays. These arrays are then used in conjunction with clinically predetermined coefficient arrays to produce diagnostic indices. These indices are sent to the host computer (18) and are displayed on the graphics display (2). Printed output of the diagnostic index is also available on the hard copy output device (22) which is connected to the microcomputer (18). The operator interacts with the acquisition and analysis components of the system by means of a user input device (24) with feedback on the graphics display (20).
A method of calculating an index indicative of anaesthetic depth, the method comprising subjecting a patient to a repetitive audio stimulus, monitoring auditory evoked potentials (AEP) produced by the patient, and providing a signal corresponding to the coarseness of the monitored AEP signal, and using said signal as said index indicative of anaesthetic depth.
A method as claimed in any preceding claim wherein the raw AEP signal is sampled at regular intervals to produce a digitised AEP signal.
A method as claimed in any preceding claim wherein an indication of coarseness is obtained by measuring the differences between neighbouring sample points.
A method of maintaining closed-loop control of an anaesthesia depth, the method comprising supplying a dosage of anaesthetic to a patient, calculating an anaesthetic depth index according to the above first aspect of the present invention, and using the value of the anaesthetic depth index to regulate the anaesthetic supply to maintain the anaesthesia depth index at or near a predetermined level.
A system for calculating an index of anaesthetic depth, the system comprising a signal generator for subjecting a patient to a repetitive audio stimulus, electroencephalographic (EEG) recording means for coupling to said patient for recording auditory evoked potential (AEP) signal from the patient, and computer means for receiving said AEP signal, and for processing said AEP signals and generating an index signal indicative of the coarseness of the recorded AEP signal, said index signal being representative of the depth of anaesthesia.
Dependencies are inferred from the claim text.