System and method for guidance of anesthesia, analgesia and amnesia

• US 20040079372A1
• Filed: 10/23/2002
• Published: 04/29/2004
• Est. Priority Date: 10/23/2002
• Status: Active Grant

• Current Assignee: New York University
• Original Assignee: New York University
• Inventors: John, Erwin R., Prichep, Leslie S.
• Granted Patent: US 7,089,927 B2
• Time in Patent Office: Days
• US Class Current: 128/204.18
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/374 Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves
• CPC Class Codes: A61B 5/38 Acoustic or auditory stimuli
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7405 using sound
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7455 characterised by tactile indication, e.g. vibration or electrical stimulation
• CPC Class Codes: A61B 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61M 16/01 specially adapted for anaesthetising A61M16/104, A61M16/18 take precedence
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/18 : Vaporising devices for anaesthetic preparations
• CPC Class Codes: A61M 16/201 : Controlled valves
• CPC Class Codes: A61M 2016/0661 : with customised shape
• CPC Class Codes: A61M 2202/048 : Anaesthetics see also A61M19/00
• CPC Class Codes: A61M 2210/0618 : Nose
• CPC Class Codes: A61M 2230/10 : Electroencephalographic signals
• CPC Class Codes: A61M 5/00 : Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests vaccination appliances for veterinary use A61D1/025 ; tube connectors, tube couplings, valves or branch units specially adapted for medical use A61M39/00; containers specially adapted for medical or pharmaceutical purposes A61J1/00; combinations of vial and syringe for mixing or transferring their contents A61J1/20; holders for containers for collecting, storing or administering blood or medical fluids A61J1/16
• CPC Class Codes: A61M 5/1407 : Infusion of two or more substances
• CPC Class Codes: A61M 5/142 : Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

A method for monitoring anesthetization of a patient, includes the steps of removably connecting a plurality of electrodes to the scalp of the patient and administering sufficient anesthesia to the patient so that the patient attains a plane of anesthesia selected by an operator. The brain waves of the patient are then amplified and digitized after the patient has been anesthetized, before beginning the medical procedure, to obtain a first set of digital data. The brain waves of the patient are then amplified and digitized during the medical procedure to provide a second set of digital data and the first and second sets of digital data are analyzed in at least one of a time domain and a frequency domain. Separate trajectories are then computed from the data analysis trajectories for at least two different indices of an anesthetic state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI). A system for providing anesthesia to a patient, includes a plurality of electrodes, a first arrangement allowing an operator to administer anesthesia to the patient until the patient has attained a selected plane of anesthesia and a second arrangement coupled to the electrodes for amplifying and digitizing brain waves of the patient after the patient has been anesthetized, before the medical procedure has been begun to obtain a first set of digital data, the second arrangement amplifying and digitizing ongoing brain waves of the patient during the medical procedure to provide a second set of digital data in combination with a third arrangement analyzing the first and second sets of digital data in at least one of a time domain and a frequency domain, a fourth arrangement computing from the data analysis separate trajectories for at least two different indices of a state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI), a fifth arrangement providing control signals when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia and a sixth arrangement automatically adjusting two different anesthetic agents administered to the patient based on the control signal to restore the patient to the selected plane of anesthesia.

Claims

1. A method for monitoring anesthetization of a patient undergoing a medical procedure, comprising the steps of:

(a) removably connecting a plurality of electroencephalograph (“

EEG”

) electrodes to a scalp of the patient;

(b) administering sufficient anesthesia to the patient so that the patient attains a plane of anesthesia selected by an operator;

(c) amplifying and digitizing brain waves of the patient after step (b) and before beginning the medical procedure to obtain a first set of digital data;

(d) amplifying and digitizing brain waves of the patient during the medical procedure to provide a second set of digital data;

(e) analyzing the first and second sets of digital data in at least one of a time domain and a frequency domain; and

(f) computing from the data analysis of step (e) separate trajectories for at least two different indices of an anesthetic state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI), wherein the DI corresponds to a depth of anesthesia of the patient, PI corresponds to a sensitivity of the patient to pain and MI corresponds to an ability of the patient to form and store memories.

2. The method as in claim 1, further comprising the steps of:

(g) providing a control signal when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia; and

(h) automatically, in response to the control signal, adjusting an amount of an anesthetic agent administered to the patient to restore the patient to the selected plane of anesthesia.

3. The method as in claim 2, wherein a plurality of anesthetic agents are administered to the patient with each of the anesthetic agents being directed primarily toward regulating a corresponding one of the indices, with the amount of each being controlled as a function of the trajectory corresponding to that index.

4. The method as in claim 2, wherein trajectories are computed for each of the DI, MI and the PI and wherein the plurality of anesthetic agents includes three anesthetic agents with each anesthetic agent being directed toward regulating a corresponding one of the DI, MI and PI.

5. The method as in claim 3, further comprising the step of:

computing an adaptive transfer function for each of the indices, wherein each transfer function reflects an effect on each selected trajectory of at least one of an addition and a reduction of the anesthetic agent directed primarily toward regulating the index corresponding to the selected trajectory.

6. The method as in claim 1, further comprising the step of displaying each of the trajectories.

7. The method as in claim 1, wherein the plurality of electrodes includes three electrodes.

8. The method as in claim 1, wherein in step (c) the frequency domain is analyzed using at least one of a Fast Fourier Transform (FFT) and an Inverse Fast Fourier Transform (IFF).

9. The method as in claim 1, further comprising the step of stimulating the patient to obtain evoked responses both before and during the medical procedure, the stimulations including an auditory stimulus at a first frequency F1 and a somatosensory stimulus at a second and different frequency F2.

10. The method as in claim 1, wherein the first set is a sample of at least one minute of artifact free data.

11. The method as in claim 1, further comprising the step of comparing the first and second sets to data derived from a control group of patients undergoing the same medical procedure and using the same anesthetic agent.

12. The method as in claim 3, wherein a first one of anesthetic agents primarily related to the MI is midazolam and a second anesthetic agent primarily related to the PI is remifentanyl and a third anesthetic agent primarily related to the DI is propofol.

13. The method as in claim 1, further comprising the step of computing the indices based on a comparison of one of the first and second sets of data with data representing population norms.

14. A method of providing anesthesia to a patient undergoing a medical procedure, comprising the steps of:

(a) removably connecting a set of a plurality of electroencephalograph (“

EEG”

) electrodes to a scalp of the patient;

(b) administering sufficient anesthesia to the patient for the patient to attain a plane of anesthesia selected by an operator;

(c) amplifying and digitizing brain waves of the patient during the medical procedure to provide a first set of digital data;

(d) analyzing the first set of digital data in a time domain and a frequency domain;

(e) computing from the data analysis separate trajectories for at least two different indices of a state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI); and

(f) providing a control signal when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia.

15. The method as in claim 14, further comprising the step of automatically, in response to the control signal, adjusting an amount of an anesthetic agent provided to the patient to restore the patient to the selected plane of anesthesia.

16. The method as in claim 15, wherein a plurality of anesthetic agents are administered to the patient, each of the anesthetic agents being primarily directed to correct digression of a corresponding one of the indices and being controlled based on the trajectory corresponding to that index.

17. The method as in claim 14, wherein the trajectories are computed for each of the DI, the MI and the PI.

18. The method as in claim 16, further comprising the step of computing an adaptive transfer function for each of the indices, each transfer function reflecting effects on each selected trajectory of at least one of addition and reduction of the corresponding anesthetic agent.

19. The method as in claim 14, further comprising the step of displaying each of the trajectories.

20. The method as in claim 14, wherein the plurality of EEG electrodes includes five electrodes connected to the forehead of the patient.

21. The method as in claim 14, wherein the frequency domain is analyzed using a Fast Fourier Transform (FFT) and an Inverse Fast Fourier Transform (IFFT).

22. The method as in claim 14, further comprising the step of stimulating the patient to obtain evoked responses both before and during the medical procedure, the stimulations including an auditory stimulus at a first frequency F1 and a somatosensory stimulus at a second frequency F2.

23. The method as in claim 14, further comprising the step of obtaining a second set of digital data including a predetermined adequate sample of artifact free reference data.

24. The method as in claim 14, further comprising the step of comparing one of the first and second sets of data to a third set of data representing a control group of patients undergoing the same medical procedure and using the same anesthesia.

25. The method as in claim 16, wherein the plurality of anesthetic agents includes first, second and third anesthetic agents, with the first anesthetic agent corresponding to the MI being midazolam and the second anesthetic agent primarily related to the PI being remifentanyl and the third anesthetic agent primarily related to the DI being propofol.

26. The method as in claim 17, further comprising the step of computing the indices as a function of current data and data representing a self-norm of the patient and as a function of a comparison of current data to population norms.

27. A method for providing anesthetization of a patient, comprising the steps of:

(a) removably connecting a set of at least two electroencephalograph (“

EEG”

) electrodes to a scalp of the patient;

(b) administering sufficient anesthesia to the patient so that the patient attains a plane of anesthesia selected by an operator;

(c) amplifying and digitizing brain waves of the patient after step (b) and before beginning a medical procedure to obtain a first set of digital data;

(d) amplifying and digitizing ongoing brain waves of the patient during the medical procedure to provide a second set of digital data;

(e) analyzing the first and second sets of digital data in at least one of a time domain and a frequency domain;

(f) computing from the data analysis of step (e) separate trajectories for at least two different indices of an anesthetic state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI); and

(g) providing a warning signal to the operator when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia to allow the operator to manually adjust an amount of an anesthetic agent administered to the patient to return the patient to the selected plane of anesthesia.

28. The method as in claim 27, wherein the trajectories are computed for each of the DI, the MI and the PI.

29. The method as in claim 28, further comprising the steps of:

administering a plurality of anesthetic agents to the patient, each of the anesthetic agents being directed primarily toward regulation of a corresponding one of the DI, MI and PI; and

computing an adaptive transfer function for each of the indices, wherein each transfer function reflects an effect on the selected trajectory of at least one of addition and reduction of the anesthetic agent primarily directed toward regulation of the index corresponding to the selected trajectory.

30. A system for providing anesthesia to a patient undergoing a medical procedure, comprising:

(a) a plurality of electroencephalograph (“

EEG”

) electrodes adapted to be connected to the scalp of a patient;

(b) a first arrangement allowing an operator to administer anesthesia to the patient until the patient has attained a selected plane of anesthesia;

(c) a second arrangement coupled to the electrodes for amplifying and digitizing brain waves of the patient after the patient has been anesthetized, before the medical procedure has been begun to obtain a first set of digital data, the second arrangement amplifying and digitizing ongoing brain waves of the patient during the medical procedure to provide a second set of digital data;

(d) a third arrangement analyzing the first and second sets of digital data in at least one of a time domain and a frequency domain;

(e) a fourth arrangement computing from the data analysis separate trajectories for at least two different indices of a state of the patient during the medical procedure, the indices being selected from a group including a Depth Index (DI), a Memory Index (MI) and a Pain Index (PI);

(f) a fifth arrangement providing control signals when any of the trajectories indicates that the patient is deviating from the selected plane of anesthesia; and

(g) a sixth arrangement automatically adjusting at least two different anesthetic agents administered to the patient based on the control signal to restore the patient to the selected plane of anesthesia, each of the anesthetic agents being primarily directed to correcting digression in a corresponding one of the indices.