Closed loop drug administration method and apparatus using EEG complexity for control purposes
First Claim
1. A method for administering an hypnotic drug to a patient to establish a desired hypnotic level in the patient, said method comprising the steps of:
- (a) establishing a reference signal corresponding to the desired hypnotic level to be provided established in the patient from the administration of the hypnotic drug;
(b) administering the hypnotic drug to the patient;
(c) obtaining EEG signal data resulting from cerebral activity of the patient and obtaining EMG signals resulting from muscle activity of the patient;
(d) deriving at least one measure of the complexity characteristics of the EEG signal data;
(e) deriving a measure of patient EMG activity;
(f) determining the hypnotic level existing in the patient from the complexity characteristics of the EEG signal data combined with the derived measure of patient EMG activity and providing a feedback signal corresponding to the hypnotic level existing in the patient;
(f)(g) comparing the feedback signal corresponding to the hypnotic level existing in the patient as a result of the administration of the hypnotic drug to the reference signal corresponding to the desired hypnotic level to be established in the patient from the administration of the drug to produce a control signal, indicative of the difference between the desired hypnotic level and the existing hypnotic level; and
(g)(h) controlling the administrationamount of the hypnotic drug administered to the patient in accordance with the comparison of step (f)control signal so that the hypnotic level of the patient is established and maintained at that corresponding to the reference signal.
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Abstract
A closed loop method and apparatus for controlling the administration of an hypnotic drug to a patient. Electroencephalographic (EEG) signal data is obtained from the patient. At least one measure of the complexity of the EEG signal data is derived from the data. The complexity measure may comprise the entropy of the EEG signal data. The EEG signal data complexity measure is used as the feedback signal in a control loop for an anesthetic delivery unit to control hypnotic drug administration to the patient in a manner that provides the desired hypnotic level in the patient. An EEG signal complexity measure obtained from the cerebral activity of the patient can be advantageously used in conjunction with a measure of patient electromyographic (EMG) activity to improve the response time of hypnotic level determination and of the feedback control of drug administration. A pharmacological transfer function may be used, along with pharmacokinetic and pharmacodynamic models.
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Citations
54 Claims
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1. A method for administering an hypnotic drug to a patient to establish a desired hypnotic level in the patient, said method comprising the steps of:
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(a) establishing a reference signal corresponding to the desired hypnotic level to be provided established in the patient from the administration of the hypnotic drug;
(b) administering the hypnotic drug to the patient;
(c) obtaining EEG signal data resulting from cerebral activity of the patient and obtaining EMG signals resulting from muscle activity of the patient;
(d) deriving at least one measure of the complexity characteristics of the EEG signal data;
(e) deriving a measure of patient EMG activity; (f) determining the hypnotic level existing in the patient from the complexity characteristics of the EEG signal data combined with the derived measure of patient EMG activity and providing a feedback signal corresponding to the hypnotic level existing in the patient;
(f)(g) comparing the feedback signal corresponding to the hypnotic level existing in the patient as a result of the administration of the hypnotic drug to the reference signal corresponding to the desired hypnotic level to be established in the patient from the administration of the drug to produce a control signal, indicative of the difference between the desired hypnotic level and the existing hypnotic level; and
(g)(h) controlling the administrationamount of the hypnotic drug administered to the patient in accordance with the comparison of step (f)control signal so that the hypnotic level of the patient is established and maintained at that corresponding to the reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. Apparatus for administering an hypnotic drug to a patient to establish a desired hypnotic level in the patient, said apparatus comprising:
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(a) means for establishing a reference signal corresponding to a the desired hypnotic level for to be established in the patient from the administration of the hypnotic drug;
(b) an anesthetic delivery unit for administering the hypnotic drug to the patient;
(c) a sensor means for obtaining EEG signal data resulting from the cerebral activity of the patient and for obtaining an EMG signal resulting from muscle activity of the patient;
(d) means coupled to said sensor means for deriving at least one measure of the complexity characteristics of the EEG signal data and for deriving a measure of EMG activity from the EMG signal, for determining the hypnotic level existing in the patient from the complexity characteristics of the EEG signal data combined with the derived measure of EMG activity, and for providing a feedback signal corresponding to same the hypnotic level existing in the patient; and
(e) a control unit including a comparator having inputs coupled to said elements (a) and (c) (d) and an output coupled to element (b), said comparator comparing the signals feedback signal corresponding to the hypnotic level existing in the patient as a result of the administration of the hypnotic drug and the reference signal corresponding to the desired hypnotic level to be established in the patient from the administration of the drug and providing an output signal to the anesthetic delivery unit, indicative of the difference between the reference and feedback signals, for controlling the anesthetic delivery unit and the administration amount of the hypnotic drug administered to the patient by the anesthetic delivery unit in accordance with the comparison output signal so that the hypnotic level of the patient is established and maintained at that corresponding to the reference signal. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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Specification