DETECTION OF ANOMALIES IN MEASUREMENT OF LEVEL OF HYPNOSIS

• US 20080317672A1
• Filed: 06/20/2007
• Published: 12/25/2008
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Viertio-Oja, Hanna E.
• Granted Patent: US 9,398,863 B2
• Time in Patent Office: Days
• US Class Current: 424/9.2
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/18 Vaporising devices for anaesthetic preparations
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 2230/10 Electroencephalographic signals
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G09B 23/28 for medicine
• CPC Class Codes: G16H 20/10 relating to drugs or medications, e.g. for ensuring correct administration to patients
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

The invention relates to detection of anomalies related to a measurement of the hypnotic level of a subject. In order to detect when a measure indicative of the hypnotic level of a subject is anomalous either due to a medical reason or due to an interference, the measure is monitored and state information indicative of the activity of the autonomous nervous system of the subject and drug effect information indicative of the hypnotic drug effect in the subject are employed to check whether the measure fulfills a predetermined consistency condition requiring that the measure changes consistently with at least one of the drug effect information and the state information. An anomaly, indicative of an abnormal change in the measure, is detected when the measure fails to fulfill the predetermined consistency condition.

Claims

1. A method for detecting an anomaly in a measurement of the hypnotic level of a subject, the method comprising:

monitoring a measure indicative of the hypnotic level in the subject;

receiving state information indicative of the activity of the autonomous nervous system of the subject;

receiving drug effect information indicative of the hypnotic drug effect in the subject;

checking whether the measure fulfills a predetermined consistency condition requiring that the measure changes consistently with at least one of the drug effect information and the state information; and

detecting an anomaly when the measure fails to fulfill the predetermined consistency condition, wherein the anomaly is indicative of an abnormal change in the measure.

2. A method according to claim 1, wherein the checking includes:

defining an estimate for the measure based on a model that depends on the state information and on the drug effect information; and

determining a variable indicative of the difference of the measure and the estimate,

wherein the detecting includes detecting an anomaly when the variable fails to remain within a predetermined value range.

3. A method according to claim 1, wherein:

the checking includes checking whether changes in the measure are consistent with changes in at least one of the drug effect information and the state information; and

the detecting includes detecting the anomaly when the checking indicates that the changes in the measure are inconsistent with both the drug effect information and the state information.

4. A method according to claim 3, further comprising:

deriving a rate of change in the measure; and

comparing the rate of change to a predetermined threshold value.

5. A method according to claim 4, wherein the checking is triggered when the comparing indicates that the rate of change exceeds the predetermined threshold value.

6. A method according to claim 1, further comprising:

administering a hypnotic drug to the subject; and

controlling the administering in response to the detecting.

7. A method according to claim 6, wherein the controlling includes freezing the administering to its current state.

8. A method according to claim 1, further comprising generating, in response to the detecting, an indication informing a user about the anomaly.

9. A method according to claim 1, further comprising deriving the measure from EEG signal data obtained from the subject.

10. A method according to claim 1, further comprising deriving the state information from plethysmographic and ECG signal data obtained from the subject.

11. A method according to claim 5, wherein the checking is aborted if it is detected that the measure behaves consistently with one of the drug effect information and the state information.

12. An apparatus for detecting an anomaly in a measurement of the hypnotic level of a subject, the apparatus comprising:

a monitoring unit configured to monitor a measure indicative of the hypnotic level in the subject;

a first interface unit configured to receive state information indicative of the activity of the autonomous nervous system of the subject;

a second interface unit configured to receive drug effect information indicative of the hypnotic drug effect in the subject; and

a calculation unit configured to;

perform a consistency check based on the drug effect information and the state information, thereby to check whether the measure fulfills a predetermined consistency condition requiring that the measure changes consistently with at least one of the drug effect information and the state information; and

detect an anomaly when the measure fails to fulfill the predetermined consistency condition, wherein the anomaly is indicative of an abnormal change in the measure.

13. An apparatus according to claim 12, wherein the measure is indicative of the entropy of EEG signal data obtained from the subject.

14. An apparatus according to claim 12, wherein the calculation unit is configured to:

define an estimate for the measure based on a model that depends on the state information and on the drug effect information;

determine a variable indicative of the difference of the measure and the estimate; and

detect an anomaly when the variable fails to remain within a predetermined value range.

15. An apparatus according to claim 12, wherein the calculation unit is configured to:

check whether changes in the measure are consistent with changes in at least one of the drug effect information and the state information and

detect the anomaly when the checking indicates that the changes in the measure are inconsistent with both the drug effect information and the state information.

16. An apparatus according to claim 15, wherein the calculation unit is further configured to:

derive a rate of change in the measure;

compare the rate of change to a predetermined threshold value; and

perform the consistency check when the rate of change exceeds the predetermined threshold value.

17. An apparatus according to claim 12, further comprising a drug delivery unit configured to administer at least a hypnotic drug to the subject.

18. An apparatus according to claim 17, further comprising a pharmacokinetic model operatively connected to the second interface unit.

19. An apparatus according to claim 12, further comprising an indicator unit configured to give an indication of the anomaly.

20. An apparatus for detecting anomaly in a measurement of the hypnotic level of a subject, the apparatus comprising:

monitoring means for monitoring a measure indicative of the hypnotic level in the subject;

first reception means for receiving state information indicative of the activity of the autonomous nervous system of the subject;

second reception means for receiving drug effect information indicative of the hypnotic drug effect in the subject; and

calculation means for performing a consistency check based on the drug effect information and the state information, the calculation means being configured (i) to check whether the measure fulfills a predetermined consistency condition requiring that the measure changes consistently with at least one of the drug effect information and the state information and (ii) to detect an anomaly when the measure fails to fulfill the predetermined consistency condition, wherein the anomaly is indicative of an abnormal change in the measure.

21. A computer program product for detecting anomalies in a measurement of the hypnotic level of a subject, the computer program product comprising:

a first program code portion configured to perform a consistency check based on drug effect information indicative of hypnotic drug effect in the subject and state information indicative of the activity of the autonomous nervous system of the subject, thereby to check whether a measure indicative of the hypnotic level of the subject fulfills a predetermined consistency condition requiring that the measure changes consistently with at least one of the drug effect information and the state information; and

a second program code portion configured to detect an anomaly when the measure fails to fulfill the predetermined consistency condition, wherein the anomaly is indicative of an abnormal change in the measure.

22. A computer program product according to claim 21, further comprising a third program code portion configured to derive the measure from EEG signal data obtained from the subject.

23. A computer program product according to claim 22, further comprising a fourth program code portion configured to derive the state information from plethysmographic and ECG signal data obtained from the subject.