System for automatic feedback-controlled administration of drugs
First Claim
1. Automatic feedback controlled apparatus for administering drugs to a subject to achieve a desired level of anesthesia, comprising:
- (a) means for sensing the subject'"'"'s EEG signal and for producing a response signal corresponding to said EEG signal;
(b) means for administering said drugs to the subject responsive to an actuating signal;
(c) preset means for establishing an order signal corresponding to the desired level of anesthesia;
(d) digital means connected to said sensing means, said means for administering and to said response signal producing means for identifying the drug/subject system model between said drug and said subject and for producing controller signals corresponding to said identified relationship; and
(e) a digital control loop connected to said means for sensing, means for administering, preset means and said digital means, for processing a difference signal, formed between said response signal and said order signal by a comparator, into a proportional component and an integral component of said difference signal to comprise said actuating signal, and further having means for establishing the ratio of proportional and integral components by said controller signals.
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Abstract
A system for automatic feedback controlled administration of drugs (SAFCAD) is disclosed for the control of administration of drugs responsive to real-time processed physiological or pharmacological signals. Control apparatus implemented by analog, digital, or optimal-adaptive digital means is described using various combinations of proportional, integral and derivative control loop processes. A preferred digital embodiment uses optimal-adaptive, proportional-integral control which includes on-line physiological system modeling and control loop parameter tuning for the administration of anesthetics such as thiopental.
278 Citations
11 Claims
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1. Automatic feedback controlled apparatus for administering drugs to a subject to achieve a desired level of anesthesia, comprising:
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(a) means for sensing the subject'"'"'s EEG signal and for producing a response signal corresponding to said EEG signal; (b) means for administering said drugs to the subject responsive to an actuating signal; (c) preset means for establishing an order signal corresponding to the desired level of anesthesia; (d) digital means connected to said sensing means, said means for administering and to said response signal producing means for identifying the drug/subject system model between said drug and said subject and for producing controller signals corresponding to said identified relationship; and (e) a digital control loop connected to said means for sensing, means for administering, preset means and said digital means, for processing a difference signal, formed between said response signal and said order signal by a comparator, into a proportional component and an integral component of said difference signal to comprise said actuating signal, and further having means for establishing the ratio of proportional and integral components by said controller signals. - View Dependent Claims (2, 3, 4, 5)
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6. A method for administering drugs to a subject to achieve a desired level of anesthesia for an extended period, comprising the steps of:
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(a) establishing a desired level of anesthesia to be attained and converting this into an order signal; (b) administering a controlled flow of drugs to said subject by controllable administering means; (c) sensing and processing the subject'"'"'s EEG signal to obtain a power response signal corresponding to the total power contained in the EEG signal; (d) determining the drug/subject system model between the administered drug and said subject by applying a pseudorandom test signal to said administering means causing a corresponding pseudorandom administration of said drug, and evaluating the corresponding pseudorandom component of said power response signal; and (e) forming an error signal as the difference between said order signal and said power response signal, and applying this error signal to electronic means having a combined proportional and integral operating mode for establishing the relative magnitudes of said proportional and integral factors in response to a predetermined function of said drug/subject system model as determined by said evaluated pseudorandom component of said power response signal. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification