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, said method comprising the steps of:
- (a) establishing a desired hypnotic level to be provided in the patient;
(b) administering the hypnotic drug to the patient;
(c) obtaining EEG signal data from the patient;
(d) deriving at least one measure of the complexity of the EEG signal data;
(e) determining the hypnotic level existing in the patient from the complexity of the EEG signal data;
(f) comparing the hypnotic level existing in the patient to the desired hypnotic level; and
(g) controlling the administration of the hypnotic drug to the patient in accordance with the comparison of step (f).
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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, said method comprising the steps of:
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(a) establishing a desired hypnotic level to be provided in the patient;
(b) administering the hypnotic drug to the patient;
(c) obtaining EEG signal data from the patient;
(d) deriving at least one measure of the complexity of the EEG signal data;
(e) determining the hypnotic level existing in the patient from the complexity of the EEG signal data;
(f) comparing the hypnotic level existing in the patient to the desired hypnotic level; and
(g) controlling the administration of the hypnotic drug to the patient in accordance with the comparison of step (f). - 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, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54)
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28. Apparatus for administering an hypnotic drug to a patient, said apparatus comprising:
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(a) means for establishing a signal corresponding to a desired hypnotic level for the patient;
(b) an anesthetic delivery unit for administering the hypnotic drug to the patient;
(c) a sensor for obtaining EEG signal data from the patient;
(d) means coupled to said sensor for deriving at least one measure of the complexity of the EEG signal data, for determining the hypnotic level existing in the patient from the complexity of the EEG signal data, and for providing a signal corresponding to same; and
(e) a control unit including a comparator having inputs coupled to said elements (a) and (c) and an output coupled to element (b), said comparator comparing the signals corresponding to the hypnotic level existing in the patient and the signal corresponding to the desired hypnotic level and providing an output signal for controlling the anesthetic delivery unit and the administration of the hypnotic drug in accordance with the comparison.
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52. The apparatus according to claim wherein the storage means stores information relating to a previous anesthetization of the patient.
Specification